Anesthesiology

HIV patients

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What should the Anesthesiologist Should Know Prior to the Operative Procedure

Background

Human immunodeficiency virus (HIV), the causative viral organism of acquired immunodeficiency syndrome (AIDS), was first recognized over 20 years ago, and has since infected approximately 50 million people worldwide. In the United States, there are between 850,000 to 1 million cases of HIV/AIDS, with 40,000 new infections documented per year. Each year, 15,000 patients die of HIV/AIDS-related complications. Almost 30% of new infections occur among women, and 82% of new infections occur in ethnic/racial minorities, predominantly among African Americans.

The most common mode of infection is sexual transmission through genital mucosa. The last decade has seen significant advances in treatment and therapy for the disease with significant effect on life expectancy. As such, the clinician needs to understand the disease, numerous new drug therapies and drug interactions, opportunistic and associated infections, and infection control techniques, in order to plan appropriate anesthetic interventions for surgery. It has been estimated that 20% to 25% of HIV-positive patients will require surgery during their illness.

Microbiology

HIV-1 is a retrovirus of the lentivirus family, containing a single-strand RNA. After entering the cell, the viral RNA is copied by a reverse transcriptase, enabling the virus to produce double-stranded DNA, which then integrates into the host’s cells. Infection is characterized by cytopathic action, a long latency period, and persistent viremia. There is a rapid rise in viremia within the first 4-11 days of infection, spreading to the lymphoid organs and central nervous system. The CD4+ T lymphocytes are infected early, and the remaining cell count helps define disease progression. Plasma viral load is initially extremely high, and then declines in the clinical latency period, lasting on average 6-12 years. As the CD4+ lymphocyte counts decline, viral loads again increase in the terminal patient.

Ultimately, a rising viral count, extreme compromise of the immune system, and a CD4+ cell count of fewer than 200 cells/mL heralds the onset of AIDS. A CD4+ cell count of less than 200 likely places a patient at a higher surgical risk. Farzio et al. suggest a 6-month postoperative mortality rate of 13.3% if the CD4+ cell count was fewer than 50 cells/mL versus a 0.8% mortality rate if the cell count was less than 200 cell/uL. While advances in medical care and pharmaceutical therapy in the last decade have changed these estimates, low CD4+ cell counts should alert the anesthesiologist to the gravity of the disease.

Diagnosis

Diagnosis of HIV infection involves identification of different antibodies to envelope glycoproteins or the p24 antigenic core. Specific HIV antibodies can be detected serologically 2-8 weeks following infection. The first to appear are immunoglobulin M (IgM) to the viral envelope glycoprotein. Following this, immunoglobulin G (IgG) to p24 core antigen and gp120 appear. These antibodies are detected using the enzyme-linked immunosorbent essay (ELISA) and more specific Western blot test. Viral load determination through DNA or HIV RNA polymerase chain reaction amplification is used for diagnostic quantification and monitoring of HIV treatment.

1. What is the urgency of the surgery?

What is the risk of delay in order to obtain additional preoperative information?

It is estimated that 20% to 25% of HIV-positive patients will require surgery during their illness, and this number is likely to rise with advances in medical management of HIV. While no specific guidelines exist regarding the implications and risk of delay of surgery for additional preoperative management, diagnostic studies, and clinical monitors of disease burden, likely the clinician can apply the same paradigm as with most ongoing, chronic medical conditions. The clinician must balance the urgency of the procedure and indication with the need for additional preoperative testing, treatment of infections, and monitoring of progression of disease.

If surgery is indicated, then evaluation and possible delay should proceed as with all other patients, with specific emphasis on functional capacity, type of surgery, and clinical evaluation of cardiopulmonary disease burden.

2. Preoperative evaluation

The most common complications of HIV and HIV-related treatments of concern to the anesthesiologist include central and peripheral nervous system, pulmonary, cardiac, gastrointestinal, hematological, renal, and endocrine and metabolic abnormalities. Preoperative evaluation should focus specifically on these organ systems, with possible further diagnostic testing if indicated. Additionally, a thorough knowledge of HIV-related medications and their potential for interaction with perioperative medications is indicated for each patient.

  1. Medically unstable conditions warranting further evaluation are the same as with all other patients presenting for surgical intervention, and involve consideration of the nature of the procedure, patient risk factors, and the urgency of the procedure. As outlined in the most recent American Heart Association/American College of Cardiology (AHA/ACC) guidelines.

  2. Delaying surgery may be indicated if any of the following conditions exist: unstable angina, recent myocardial infection or active ischemia, congestive heart failure, unstable arrhythmias, stroke, transient ischemic attack (TIA), chronic obstructive pulmonary disease (COPD) exacerbation, or other unstable conditions. Specifically, opportunistic infections causing pulmonary (i.e., Pneumocystis carinii pneumonia), cardiac (i.e., myocarditis), or renal (medication-related) abnormalities may warrant delay of nonemergent procedures until underlying conditions can be optimized.

3. What are the implications of co-existing disease on perioperative care?

N/A

b. Cardiovascular system

Background

Patients with HIV infections are living longer, and the extent of involvement of the cardiovascular system is increasingly apparent. Cardiac involvement is multifactorial, and includes chronic viral infections, drug therapy, and immunosuppresion. AIDS has an increasingly recognized association with several cardiac abnormalities:

  1. Accelerated coronary artery disease: Antiretroviral therapy commonly causes dyslipidemias, particularly the protease inhibitors, and often has a severe atherogenic profile. The end-result of HAART (highly active antiretroviral) therapy is an increase in low-density lypoprotein (LDL) and triglycerides and a decrease in high-density lypoprotein (HDL). Patients on this therapy are at unique risk of major cardiovascular disease despite their often relatively young age.

  2. Cardiomyopathy: In the pre-HAART era, dilated cardiomyopathy was described in 30%-40% of AIDS patients. This incidence has likely significant decrease with advances and widespread adoption of HAART. However, some antiretroviral therapy can be cardiotoxic and cause decreased contractility.

  3. Pulmonary hypertension (PH): PH is a rare but serious consequence of HIV. The incidence is approximately 1/200.

  4. Myocarditis: Has been commonly associated with advanced disease and was found in 40%-52% of patients who died of HIV. No specific organism was found in 80% of patients, but in others, Toxoplasma gondii, Cryptococcal neoformans, and Mycobacterium tuberculosis were found. Myocarditis can also be related to viral and neoplastic (i.e., lymphoma, Kaposi’s sarcoma) diseases.

  5. Pericardial effusions: Occurs in 11% of asymptomatic AIDS patients prior to the introduction of HAART, but this therapy has significantly reduced the incidence.

  6. Hypercoagulability: The literature contains reports of thrombotic episodes and various predisposing abnormalities related to a hypercoagulable state that correlate with the severity of HIV disease. The coexistence of HIV-related illness, such as malignancies and autoimmune diseases, as well as antiretroviral therapy itself, may also predispose these patients to thrombotic phenomenon.

  7. Anemia/thrombocytopenia: Occurs in 2.8% of patients with a CD4+ T cell count of >700 cells/mL, but increased to 10.8% when cell counts decreased below 250. This may develop as a result of HIV-related immune thrombocytopenia, retroviral infection of bone marrow progenitors, or drug-induced bone marrow suppression (i.e., zidovudine/AZT).

Preoperative evaluation

In general, preoperative evaluation of the HIV-patient with cardiac disease is similar to non-HIV patients with significant risks for cardiovascular disease.

Early identification of cardiovascular disease in the HIV patient. This is easily accomplished with a clinical history (functional status, changes in exercise tolerance, fatigue), focused physical exam (bruits, murmurs, fundoscopy), prior electrocardiography (ECG) or noninvasive stress testing if available, and possibly speaking with patient’s cardiologist, primary care physician, or infectious disease specialist.

Further diagnostic testing if warranted (i.e., active unstable condition, changes anesthetic management, important surgical implications). A baseline ECG and/or chest x-ray is warranted in younger patients with suspicion of cardiac disease.

Appropriate preoperative optimization of comorbid cardiovascular conditions.

  • Ischemic coronary disease - Medical management includes aspirin, beta blockade, statins, nitrates, etc. The benefits of preoperative revascularization based on American Heart Association/American College of Cardiology (AHA/ACC) Guidelines is likely only based on functional status and the nature of the surgical procedure.

  • Cardiomyopathy and myocarditis – These conditions are managed medically with specific attention to treatment of underlying causes or infections, and symptomatic control with diuretics.

  • Pericardial effusions may require drainage if there is significant impairment of cardiac function or functional capacity.

Perioperative risk reduction strategies

The goals of the perioperative physician are to maintain an adequate balance of myocardial oxygen supply and demand, while minimizing the risk to any areas of vulnerable myocardium.

  1. Intraoperative monitoring is based on patient’s underlying conditions. No additional monitoring is required. If significant cardiovascular disease is present, full monitoring (arterial line, central venous catheter, transesophageal echocardiographic [TEE]) may be warranted.

  2. Intraoperative management of HIV patients with significant cardiac disease is identical to management of all other patients with coronary artery disease. Goals should be on maximizing myocardial oxygen supply and reducing oxygen demand. Supply may be increased with increasing FiO2, transfusions as necessary, and reduction of heart to maximize diastolic perfusion. Demand can be reduced by augmenting heart rate, contractility, and afterload. Ideal preload conditions are based on ejection fraction, right- versus left-sided disease, and presence/absence of significant pericardial effusion.

  3. Patients with significant degrees of hemodynamic compromise related to pericardial effusion or tamponade present significant anesthetic challenges. As with all tamponade, the physiologic goals are to maintain adequate preload and afterload, as well as maintaining elevated heart rate as the primary determinants of cardiac output. Often, patients can be sufficiently anesthetized utilizing vagolytic or sympathomimetics medications, such as ketamine, pancuronium, ephedrine, and epinephrine.

c. Pulmonary

Preoperative evaluation

Perioperative pulmonary complications in the HIV patient are primarily related to coexisting opportunistic infections. HIV/AIDS patients are at significant risk of developing pulmonary infections that can rapidly progress into respiratory failure if not treated appropriately. The primary causes include Pneumocystis carinii, bacterial, tuberculosis, aspergillosis, Cytomegalovirus (CMV), and herpetic infections. These can progress to respiratory distress and failure, pneumatocoeles, pneumothoraces, and acute respiratory distress syndrome (ARDS). Further, tuberculosis, whose incidence is increasing among women with HIV of child-bearing age, may present significant risks to other patients and health care workers if not appropriate identified, treated, and contained.

Preoperative evaluations should focus on identification of pulmonary disease, evaluation of the degree of respiratory compromise, and consideration of type and location of procedure given a patient’s pulmonary status. Unless suspecting acute infection or pulmonary compromise, pulmonary testing or imaging may be unnecessary and delay surgery. In patients with significant degrees of pulmonary compromise or those undergoing higher-risk procedures, further workup with chest x-ray, chest computerized tomography, resting arterial blood gases, pulmonary function tests, and other diagnostic studies may be indicated. If the patient has known pulmonary infection, anesthesiologist should be aware of the treatment and degree of residual pulmonary involvement. Also, as patients with HIV/AID have improved life expectancy, the presence of other chronic lung diseases such as asthma, COPD, and bronchiectasis (from recurrent infections) should be anticipated.

Perioperative risk reduction strategies

  1. Identification of presence of pulmonary infections. An HIV/AIDS patient with a CD4+ T cell lymphocyte count of <200 cells/mL is at high risk of developing PCP or Mycobacterium avium complex pneumonias, and often is on prophylactic antibiotics. A chest x-ray in an otherwise relatively asymptomatic patient may be warranted if clinical suspicion for pulmonary involvement exists.

  2. Assess the degree of pulmonary compromise. Respiratory failure related to opportunistic infections may require aggressive pulmonary support or intubation, often necessitating delay of planned procedure.

  3. Assess the urgency, type, and location of procedure. Prolonged procedures or ones that may expose patient to significant risk of post-operative respiratory failure (i.e. thoracotomy, upper abdominal surgery) may necessitate delay until recovery of pulmonary function.

  4. If anti-infectives are being instituted either prophylactically (i.e., for PCP pneumonia) or for treatment, these should be continued leading up to, during, and after the procedure.

  5. Steroids are often used in the treatment of PCP pneumonia, and these should be continued perioperatively. The use of stress dose steroids is not routinely recommended, but is at the discretion of the perioperative provider.

  6. If possible, consider regional technique with sedation to avoid airway instrumentation, mechanical ventilation, and intravenous (IV) medications or narcotics that can alter pulmonary mechanics.

  7. If a general anesthetic is chosen, appropriate attention should be paid to altered gas exchange from pneumonia, presence of secretions that can cause alteration in pulmonary mechanics and pressures, and the need for intraoperative pulmonary toilet (bronchodilators, recruitment, bronchoscopy).

  8. The clinician should be aware that aerosolized pentamidine can cause significant perioperative bronchospasm.

  9. An arterial line may be useful to evaluate gas exchange.

  10. Postoperatively, continued pulmonary toilet, incentive spirometry, and nebulizer treatments may be required. Antibiotics should be continued. If patient has severe preoperative respiratory failure but required a surgical intervention, consider the need for possible postoperative continued intubation and/or mechanical ventilation.

  11. While no special equipment is required, at the conclusion of the procedure, all equipment should be cleaned with appropriate anti-infective solutions. Similarly, patients with known or suspected tuberculosis should remain on appropriate precautions during the transport and the perioperative period in order to reduce the risk of transmission to other patients and health care workers.

d. Renal-GI

Preoperative evaluation

HIV patients are at risk for developing various renal diseases caused by HIV infection, viral hepatitis, drug abuse, antiretroviral drugs, and dehydration. Although it is difficult to estimate, approximately 30% of HIV patients have some form of kidney disease. HIV-associated nephropathy is a clearly identified clinicopathologic syndrome. Nearly 1% of patients with end-stage renal disease (ESRD) in the United States and Europe are infected with HIV. Furthermore, kidney diseases that are distinct from HIV, such as those related to diabetes or hypertension (which can be related to many antiretroviral medications), are likely to develop among HIV-infected patients, since most of these patients now survive for many years and suffer from the long-term consequences of these diseases. Preoperative evaluation of HIV patients with kidney disease involves:

  1. Identification of the presence and/or degree of compromise of kidney function. Tests commonly used to identify and quantify renal disease include baseline serum creatinine, estimated glomerular filtration rate (based on the Cockcroft-Gault calculation), urine electrolytes and protein, as well as renal ultrasound or biopsy. Often, due to muscle wasting and chronic malnutrition, serum creatinine levels may not be indicative of actual glomerular function.

  2. Etiology. HIV-associated nephropathy (nephrotic syndrome), HIV infection, viral infection, drug abuse, antiretroviral drugs (especially adefovir foscarnet, and indinavir), underlying comorbid or medication-related condition such as diabetes, dyslipidemias, advanced vascular disease.

  3. Treatment. Management of volume status, electrolyte abnormalities, anemia/thrombocytopenia, renal replacement therapy (including frequency, last dialysis, volume status, need for transfusions, type of replacement, and access), management of associated comorbid conditions such as diabetes, hypertension.

  4. Evaluation of most current electrolyte profiles including creatinine, glomerular filtration rate (GFR), calcium and phosphate, degree of anemia/thrombocytopenia with implicated renal dysfunction-induced platelet dysfunction, and coagulation studies if indicated. Advanced renal disease often occurs and may in fact hasten underlying cardiovascular disease; appropriate clinical suspicion and diagnostic studies should be pursued.

Perioperative risk reduction strategies

Primary aim is to avoid secondary injury to the kidneys. Often, urinary output is used a general marker of perioperative intravascular rescuscitation.

  1. Continuation of renal-related medications in the perioperative period (i.e., Renagel, PhosLo, calcium supplementation)

  2. Adequate perioperative hydration, with careful attention to preoperative volume status. This may require judicious use of volume and resuscitation, and monitoring of central pressures or transesophageal echocardiography may be indicated based on the surgery and degree of fluid shifts anticipated.

  3. Maintenance of renal perfusion pressure, with avoidance of excessive and prolonged hypotension or alternatively, high vasopressor use.

  4. Maintenance of adequate urine output may be accomplished with fluid resuscitation and/or diuretics.

  5. Medicationsshould be adjusted for degree of renal impairment. Avoid renally-clearedmedications if possible (pancuronium, morphine, etc.)

  6. Postoperativemonitoring of urine output and kidney function is indicated. If patientis on preoperative renal replacement therapy, plans should beimplemented in coordination with patient’s nephrologist for continuationpostoperatively.

e. Neurologic

Background

Neurological involvement begins within days of the initial infection. HIV has been isolated from the cerebrospinal fluid (CSF) during primary infection. It is unknown what determines the extent of neurological involvement. It is speculated that some strains of the virus are particularly neurotropic.

About 30% of adults and 50% of children suffering from AIDS will develop neurological disorders. Virtually all patients have evidence of central nervous system infection, regardless of the presence and/or degree of symptoms.

Blood studies are often needed to exclude concomitant diabetes mellitus, vitamin deficiencies, alcoholism, hereditary diseases, and other infectious sources (i.e., Lyme disease).

  1. Acute disease: Related to acute infection with neurotropic HIV virus.

    • Vacuolar myelopathy - sensory disturbances, spasticity and hyperreflexia

    • Peripheral neuropathy - distal, symmetric numbness, tingling, painful dyesthesias and paresthesias, concomitant myopathy

    • Brachial neuritis

    • Cauda equina syndrome

    • Guillain-Barré syndrome

    • Headaches

    • Photophobia

    • Acute meningoencephalitis

    • Depression

    • Irritability

    • Cranial nerve neuropathies

  2. Latent phase: Likely an autoimmune process triggered by HIV

    • Chronic inflammatory demyelinating neuropathies resembling a subacute Guillain-Barré syndrome

    • Autonomic dysfunction: may appear with or without central nervous system (CNS) abnormalities. May present with uncommon autonomic disturbances such as orthostatic syncope, hypotension, and diarrhea.

  3. Chronic/late disease: Caused by wide variety of opportunistic infections or immunocompromise-related neoplasm.

    • Meningitis: Cryptococcus, tuberculosis, syphilitic, herpes simplex vrius (HSV), CMV

    • Toxoplasmosis

    • CNS lymphoma

    • AIDS encephalopathy or AIDS dementia complex – cognitive, motor, behavior changes

    • Vacuolar myelopathy – sensory disturbances, spasticity, and hyperreflexia

    • Segmental (focal) myelopathy

    • Myopathy

    • Peripheral neuropathy

    • Progressive multifocal leukoencephalopathy

Preoperative evaluation

  1. A careful history and physical exam can alert the clinician to neurological abnormalities, as well as a discussion with the patient and their primary care physician, infectious disease specialist, or neurologist. It is important to identify and document the presence or absence of neurological abnormalities preoperatively in order to monitor if changes occur perioperatively.

  2. The stage of patient’s HIV (early vs.late, CD4+ count, viral load) can alert the clinician for what types of neurological abnormalities to anticipate (both known and unknown), and adjust the anesthetic plan accordingly.

  3. Careful review of any preoperative diagnostic studies including computed tomography (CT), magnetic resonance imaging (MRI),electroencephalography (EEG), electromyography (EMG), LP, and muscle or brain biopsy can aide in reviewing the diagnosis and understanding the current level of treatment.

  4. HIV infection, intracranial masses, or opportunistic infections (especially toxoplasmosis) may cause cerebral edema, cerebral hemodynamic disturbances, and increased intracranial pressure. A careful history and physical exam, including a fundoscopic examination are warranted, as well as further workup (LP, CT scan) if clinical suspicion exists. This can be difficult to establish as headache, nausea, vomiting, and photophobia can be relatively nonspecific symptoms in the perioperative period. Often, these infections respond quickly to medical therapy and surgery should be postponed whenever possible when they are present.

  5. Signs and symptoms of autonomic dysfunction should be elicited preoperatively if present.

  6. Appropriate identification and documentation of preoperatively neurological deficits, paresthesias,neuropathies, etc. is extremely important for both perioperative care and from a medicolegal standpoint. Peripheral neuropathy is the most frequent neurological complication in HIV patient, affecting up to 35% of patients with AIDS and clinically manifests as a polyneuropathy and myopathy.

Perioperative risk reduction strategies

  1. Careful review of the preoperative evaluation and changes from baseline on the day of the planned procedure.

  2. Standard monitoring is indicating, as well as potentially an arterial line if concern exists for changes inintracranial pressure or autonomic dysfunction.

  3. Although no specific contraindications exists, one should carefully review the presence and extent of concomitant myopathy, myelopathy, and Guillain-Barré syndrome,which can significant impact the use of both non-depolarizing and depolarizing muscle relaxants. The complications associated with the use of succinylcholine (hyperkalemia) are only a potential risk; no such complications have yet been reported in the literature. While not an absolute contraindication, succinylcholine should be used with caution. Similarly, if significant musculoskeletal disease exists, then establishment of full muscle strength should precede extubation,otherwise patients may require post-operative mechanical ventilation.

  4. Patients with HIV and especially later stage AIDS, AIDS encephalopathy, or AIDS-related dementia complex tend to be more sensitive to opioids and benzodiazepines, reflecting the extent of neurological involvement. The probable mechanism is based on increased interleukin-1 levels causing an increased GABA-mediator production. Similarly, these patients are at significant risk of postoperative delirium. While a regional technique may be an option, due to the nature of the procedure or patient cooperation and need for sedation this may be unfeasible. Postoperative delirium should be treated appropriately, treating all secondary causes (i.e., pain, full bladder), frequent reorientation, and low-dose antipsychotic medications as needed.

  5. As peripheral neuropathy is the most common neurological complication of HIV/AIDS, careful attention should be paid to positioning of the patient in the perioperative period. Meticulous attention should be paid to padding pressure points or other vulnerable areas. Patients with significant spasticity may present unique difficulties with position,and should be maintained in as neutral position as possible.

  6. The clinician should be prepared for any acute changes in intracranial pressure, especially if concerns existed preoperatively. This includes avoiding large changes in cerebral perfusion pressure (i.e., during intubation and extubation) and therapeutic maneuvers if concern for suchchanges exist (hyperventilation, elevating the head of the bed, diuretics). Neuraxial anesthesia is contraindicated in patients with known or suspected elevated intracranial pressures or CNS infections.

  7. The clinician should be prepared for possible cardiovascular abnormalities in patients with significant degrees of autonomic dysfunction. A preoperative arterial line may be useful, and maintaining a deep level of anesthesia may be indicated to avoid wide changes in blood pressure.

  8. Medications for the treatment of neurological disorders (especially seizure medications, treatments for spatisticity) can cause significant interaction with multiple anesthetic drugs, particularly at the level of liver metabolism (i.e., muscle relaxants), often decreasing the duration of action. Frequent twitch monitoring is indicated if muscle relaxation is required.

  9. The majority of medications for the treatment of neurological disorders should be continued in the perioperative period. Treatment for CNS infections should be maintained.

  10. Postoperatively it is important to continue to monitor the neurological examination of the patient, with specific attention to baseline abnormalities and the development of new deficits. If new deficits should arise in the perioperative period, further diagnostic workup in coordination with neurologic or infectious disease consultation is warranted.

f. Endocrine

Background

The course of HIV and AIDS can be complicated by a variety of endocrine and metabolic abnormalities. Causes include direct effect of HIV on the endocrine gland, opportunistic infections and neoplasm, or antiretroviral drugs. Common endocrine abnormalities include:

  1. Adrenal insufficiency. Primary or secondary adrenal insufficiency is the most serious complication of HIV/AIDS. Secondary causes include infection (CMV, Nisseria meningitis) or drugs (ketoconazole, rifampin, etomidate). The incidence of clinical or biochemical adrenal insufficiency in patients with HIV disease is in fact much lower than the incidence of adrenal involvement found at autopsy, despite a number of case reports reporting the association.

  2. Hypogonadism. Commonly due to hypogonadotrophic hypogonadism or primary testicular failure.

  3. Pancreatic dysfunction. May result in hypoglycemia (from hyperinsulinemia) or diabetes (from hypoinsulinemia). The endocrine pancreatic disturbance of most clinical importance in HIV infection occurs in patients receiving pentamidine treatment for PCP. Pentamidine-induced hypoglycemia is extremely common in patients with advanced HIV disease treated for PCP (14% to 28%); this incidence is much higher than in non-HIV-infected patients treated with pentamidine for PCP (a range of 6.2% to 9.1%). Moreover, symptomatic hypoglycemia is more common among patients with advanced HIV disease (25%) than among non-HIV-infected patients.

  4. Pentamidine is a potent beta cell toxin. Destruction of beta cells may result in an unphysiologic release of stored insulin with resulting hypoglycemia. Patients experiencing pentamidine hypoglycemia can also therefore develop diabetes mellitus, with or without ketoacidosis. Itis important to recognize that the long tissue half-life of pentamidine can result in hypoglycemia days or weeks after discontinuing atherapeutic course. The true incidence of pentamidine hypoglycemia is therefore likely to be even greater than estimated from in-hospitalstudies.

  5. Thyroid function tests in HIV/AIDS patients may be abnormal, although clinical hypothyroidism is rare. This may be consistent with “sick euthyroid syndrome.”

  6. Anterior pituitary disorders. Centrally mediated hyperinsulinemic hypoglycemia may result as a complication of protease inhibitor treatment.

  7. Posterior pituitary disorders. Isolated hyponatremia is very common in patients with advanced HIV disease, is associated with poor prognosis, and is most frequently due to SIADH (syndrome of inappropriate antidiuretic hormone secretion) or renal salt-wasting, although adrenal insufficiency occasionally is the cause.

Preoperative evaluation

  1. A careful history, physical exam, and basic electrolytes panel can often indicate the presence of an endocrine disorder. Evaluation should focus on indicators of adrenal insufficiency (hyponatremia, hyperkalemia, postural hypotension, cortisol levels), pancreatic disturbances (hypo- or hyperglycemia, ketones, anion gap), and pituitary disturbances (especially hyponatremia or protease inhibitor-induced hypoglycemia).

  2. The presence of endocrine abnormalities should warrant communication with patient’s primary care physician, infectious disease specialist, or endocrinologist regarding current treatment and continued management. Often, aid can be provided for the perioperative period.

  3. Recent infection with PCP, use of protease inhibitors, or treatment with pentamidine should alert the clinician for possible perioperative issues with blood sugar control. Assess the baseline issues with blood sugar (hypo- or hyperglycemia, ketoacidosis) and current management (insulin, diet, frequent need for hypoglycemic rescue).

  4. Similarly use of recent anti-infectives such as ketoconazole or rifampin should alert the clinician for possible adrenal insufficiency.

Perioperative risk reduction strategies

  1. Review the patient’s underlying endocrine abnormalities and current treatments.

  2. Patient with preexisting adrenal insufficiency can be on maintenance steroids, although this is often avoided to present worsening of an already immunosuppressed condition. These should be continued in the perioperative period. The use of stress-dose steroids is unclear, but likely should be considered depending on the nature of the procedure, the degree of insufficiency, degree of anticipated surgical stress, and understood risks in an already immunocompromised host.

  3. The use of adrenal-suppressing medications should be avoided in all HIV/AIDS patients if possible, given the possibility of subacute adrenal insufficiency manifesting in the perioperative period. Specifically, induction agents such as etomidate and several anti-infective medications should be avoided if possible. The clinician should consider alternatives such as ketamine. If adrenal-suppressing medications are used, this should be communicated to the postoperative team, in case signs of symptoms of adrenal insufficiency develop.

  4. If patients develop signs and symptoms of adrenal insufficiency, treatment is essentially the same as in other clinical settings. Stress doses (180 to 200 mg of hydrocortisone in divided doses) are indicated during acute illnesses.

  5. Patients with known pancreatic dysfunction should have their blood sugar monitoring closely in the perioperative period, with particular attention to the avoidance of hypoglycemia. Dextrose should be immediately available in patients with hypoglycemia, and potentially a continuous intravenous infusion postoperatively until the patient is able to tolerate oral intake. Hyperglycemia should be treated by avoidance of high dextrose solutions, and insulin as needed. The use of “tight” glucose control is likely unnecessary. If patients are on insulin preoperatively, their regimen should be adjusted according to their fasting status. Patients prone to ketoacidosis should be maintained on some level of insulin, with an appropriate supplemental dextrose source.

  6. Hyponatremia presents a unique challenge in the perioperative period. Likely the goals of care are not to worsen the degree of hyponatremia by large volume infusions of hypotonic solution. Careful attention should be paid in situations where nonintravenous administration of hypotonic solution occurs (i.e., TURP [transurethral resection of the prostate]). Sodium level should be monitored closely in the perioperative period, and if symptomatic, treatment with hypertonic or normal saline should be initiated.

g. Additional systems/conditions which may be of concern in a patient undergoing this procedure and are relevant for the anesthetic plan (eg musculoskeletal in orthopedic procedures, hematologic in cancer patient)

Gastrointesinal system

Preoperative evaluation

HIV/AIDS patients commonly experience gastrointestinal complications of the disease. Common complications include:

  1. Esophagitis: Common caused by infection such as Candida albicans, CMV, herpes simplex, Mycobacterium avium-intracellulare. Malignancies, such as KS and lymphoma, and non-HIV-related disorders, such as acid-reflux esophagitis, can also occur. As with infections in other parts of the intestinal tract, the CD4 count can be used to direct the evaluation. Candida and HSV esophagitis are predominantly identified in patients with CD4 cell count less than 200 cells/mL. CMV and idiopathic ulcers are noted almost exclusively below a CD4 cell count of100 cells/mL. Although not all are symptomatic, the most common complaint is dysphagia or odynophagia.

  2. Diarrhea: The most common gastrointestinal (GI) symptom in patients with HIV. In outpatient studies, the prevalence of diarrhea ranged from 0.9 to 14%. Prevalence was increased in homosexual men and individuals with lower CD4 cell counts. In hospitalized individuals with advanced HIV, 50% of all patients had diarrhea.Cryptosporidium, Microsporidium, Isospora belli ,Giardia, CMV, Shigella, Campylobacter, or Clostridium difficile are all important infectious causes of diarrhea.

    HIV patients are also predisposed to small bowel overgrowth; the prevalence in patients with HIV-associated diarrhea was as high as 38%. Reported evidence suggests that HIV itself may be an indirect diarrheal pathogen because viral proteins have been found in the gut, termed “AIDS Enteropathy.” In patients with early HIV disease, medications are a common cause of diarrhea, especially protease inhibitors, including nelfinavir and saquinavir. The diarrhea is often self-limited, lasting less than 2 to 4 weeks from initiation of medication use.

    Weight loss: The CDC (Centers for Disease Control and Prevention) classifies wasting as an AIDS diagnosis when a patient presents with involuntary weight loss of more than 10% of baseline body weight, plus either chronic diarrhea or chronic weakness and fever in the absence of infection or a condition other than HIV disease. This may be due to either inadequate caloric intake or increased metabolic demand, often seen with progressive disease.

  3. Gastrointestinal bleeding: GI bleeding in patients with HIV disease is as likely to arise from lesions not unique to HIV infection as from HIV-associated opportunistic infections or neoplasm, occurring in less than 1% of HIV patients. Unique causes of gastrointestinal bleeding in the HIV patient are CMV-induced small bowel or colonic vasculitis, Candida and herpes esophagitis, or enteritis associated with Salmonella, Shigella, Campylobacter, or Cryptosporidium. Neoplasia such as Kaposi’s sarcoma and primary intestinal lymphoma may also cause bleeding.

  4. Hepatic abnormalities: Most patients will experience hepatobiliary manifestations at some point during the course of their HIV disease, with hepatomegaly and/or jaundice in 50% and abnormal liver function tests in over 80%. Common infectious causes include HIV itself, CMV, Epstein-Barr virus, MAC, extrapulmonary tuberculosis, Bartonella hensalae-related peliosis hepatitis, cryptococcal infections (disseminated cryptococcal meningitis),Pneumocystis carinii, and co-infections with HBV and HCV (hepatitis B and C viruses). Noninfectious etiologies include Kaposi’s sarcoma, extranodal presentation of non-Hodgkin’s lymphoma, and medications (including HAART, trimethoprin-sulfamethoxazole).

  5. Biliary abnormalities: Biliary abnormalities in patients with AIDS fall into three general categories: non-HIV-associated conditions of the bile duct (cholelithiasis, benign bile duct strictures, periampullary neoplasm of the bile duct), acalculous cholecystitis (linked to CMV and Cryptosporidium infections), and AIDS cholangiopathy.

Perioperative risk reduction strategies

  1. Esophageal reflux is common amongst many HIV/AIDS patients, which may increase the risk for pulmonary aspiration on induction of general anesthesia. Patients with infective esophagitis may indeed have functional esophageal dysmotility. A careful history is indicated.

  2. A careful history and physical examination are important in patients with chronic diarrhea and/or weight loss. The degree of malnourishment can be assessed. Hypoproteinemia can affect multiple free drug levels.

  3. Medications including anti-infectives used for the treatment of gastrointestinal disorders should be continued in the perioperative period if no surgical contraindications exist.

  4. Care should be taken with oropharyngeal and esophageal manipulation in patients with significant amount of Candida or herpes esophagitis. Repeated manipulation can cause trauma, edema, or bleeding, further complicating airway management.

  5. The value of routine use of liver function tests and coagulation profile is unclear. These should be pursued if suspicion for dysfunction exists preoperatively, or extensive surgery with blood loss and fluid shifts are expected. Perioperative correction of coagulopathy is dependent on the clinical degree of bleeding and/or planned procedures (i.e., neuraxial blockade). Underlying cirrhosis and liver failure should be managed appropriately as outlined elsewhere.

  6. Underlying biliary abnormalities can bediagnosed with liver function tests, ultrasound, orendoscopically. Attention should be paid for signs and symptoms ofhepatic involvement of biliary disease.

HIV and pregnancy

Background

Nationwide seroprevelance of HIV during pregnancy is 1.7/100 pregnancies. Majority of pediatric HIV infections resulted from vertical transmission of the virus from the mother to the infant – 4.4% during pregnancy, 60% during delivery, 35.6% during breastfeeding. From 15% to 40% of infants born to HIV-positive mothers will become infected in the perinatal period without treatment.

Rates of transmission are increased by breaks in placental barrier, prolonged rupture of membranes (> 4 hours), high cervicovaginal viral load (may not correlate with systemic load), lack of zidovudine (AZT) treatment, and vaginal delivery. The intrauterine risk of transmission is not altered by maternal AZT therapy. In recent years, vertical transmission has declined more than 60%. Maternal plasma HIV RNA levels is the best predictor of the risk of perinatal HIV transmission (< 500 viral copies/mL)

Prevention of vertical transmission

  1. Routine HIV testing should be offered and repeated if needed during pregnancy (Increase from 51% to 80% detection rate before delivery)

  2. HAART

    • Starting or continuting HAART to maximal suppression during pregnancy - may affect timing and choice of therapy but is ot a contraindication or reason to postpone therapy.

    • Little information regarding fetal toxicity

    • Efavirenz (Sustiva) is often avoided in the first trimester of pregnancy (FDA [United States Food and Drug Administration] Pregnancy Category "D - positive evidence of fetal risk) due to risk of neural tube defects.

  3. Zidovudine (AZT) chemoprophylaxis during labor and delivery

    • Reduction in vertical transmission from 25.5% to 8.3%

    • Should be offered routinely to all HIV+ parturients during labor and delivery, as well as continued neonatal treatment for 24-48 hours.

  4. American College of Obstetricians and Gynecologists recommendations for cesarean delivery for HIV-positive parturients.

    • Elective cesarean delivery combined with HAART may decrease vertical transmission to <5%

    • Elective cesarean should be offered to all HIV patients, especially those with > 1000 viral copies/mL

    • Mode of delivery should be individually assessed and are the viral load tested every 3 months

    • Routine cesarean delivery may be problematic in rural hospitals with higher complication rates related to cesarean delivery

    • Generally ought to be performed prior to 38 weeks before possibility of onset of labor or rupture of membranes

Preoperative evaluation

Review HIV status, current treatment, viral loads, and CD4+ count

Review of history and physical, with careful attention to airway exam, timing of last oral intake, other comorbid conditions, and HIV- and HAART-related complications.

If in labor or with rupture of membranes, review use of AZT.

Perioperative risk reduction strategies

1. No evidence to suggest that pregnancy alters the course of HIV infection

2. Given the possibility of exposure to body fluids, careful attention should be paid by all who interact with the patient regarding universal precautions

3. If desired, continue AZT dosing.

4. No evidence to suggest contraindications or timing to neuraxial techniques in the HIV-positive parturient.(See discussion below)

5. Occasionally the anesthesiologist may be asked to assist in neonatal resuscitation. Management includes any attempts to minimize the infant’s exposure to maternal blood and genital secretions – avoid percutaneous umbilical cord sampling, fetal scalp clips, fetal scalp monitoring, delivery techniques that could produce abrasions in the infant’s skin (i.e., vacuum or forceps), and immediate removal of maternal blood and fluids from the infant.

4. What are the patient's medications and how should they be managed in the perioperative period?

Generally most antiretroviral medications (HAART) should be continued in the perioperative period. Most patients on HAART have been on such regimens with the supervision of their infectious disease or HIV specialist in order to maintain low viral loads and optimize their CD4+ count. Although abrupt discontinuation for short periods of time (1-3 days) is unlikely to contribute to any significant change in the burden of disease, prolonged discontinuation (due to surgical interventions, ability to tolerate oral intake, postoperative ileus) should merit consultation for an alternative intravenous regimen. However, all effort should be made to resume the original medication regimen as soon as possible postoperatively.

Further, patients are often on prophylactic or therapeutic antibiotics in the perioperative period; these should be continued as well, unless specific contraindications exist.

h. Are there medications commonly seen in patients undergoing this procedure and for which should there be greater concern?

There are several common classes of medications used to treat HIV/AIDS. They are often used in combination, some of which are available as a single dose.

  1. Nucleoside analog reverse transcriptase inhibitors (NRTIs)

    • Common drugs - Zidovudine (AZT), didanosine (ddi), zalcitabine (ddC), lamivudine (3Tc), adefovir

    • Mechanism - Inhibits the complention of reverse transcription by binding to viral RNA

    • Common side effects

      • Peripheral neuropathy - up to 30% of patients treated with zalcitabien (ddC), least incidence with lamivudine (3Tc), combined HAART often improves HIV virus-related neuropathy, often reversible on cessation of therapy

      • Myopathy

      • Bone marrow suppression - seen with zidovudine (AZT).

  2. Non-nucleoside reverse transcriptase inhibotors (NNRTIs)

    • Common drugs - Nevirapine, efavirenz, delavirdine

    • Mechanism - Inhibits the enzyme reverse transcriptase by direct binding. High rate of resistance with lone therapy.

    • Common side effects

      • Skin rash/Steven-Johnson syndrome

      • Cytochrome P450 enzyme induction - may decrease serum levels of some anesthetics and sedatives such as midazolom and fentanyl, commonly seen with nevirapine.

      • Efavirenz (Sustiva) is often avoided in the first trimester of pregnancy (FDA Pregnancy Category "D" - positive evidence of fetal risk) due to risk of neural tube defects

  3. Protease Inhibitors

    • Common drugs - saquinavir, indinavir, ritonavir, nelfinavir, amprenavir

    • Mechanism - inhibits the HIV protease from binding to active cleavage site.

    • Common side effects

      • Hyperglycemia

      • Peripheral neuropathy

      • Obstructive uropathy

      • Elevated liver enzymes

      • Hypertriglyceridemia

      • Competitive inhibitors of cytochrome P450 enzymes - may increse the effects of drugs metabolized by similar enzymes such as midazolam, fentanyl, amiodarone, and quinidine. In previous studies, the risk of respiratory despression with fentanyl over a longer period of time seemed more likely in patients taking ritonavir. With even small bolus doses, it may be advisable to maintain respiratory monitoring for longer periods than usual.

  4. Other newer classes of antiretroviral medications include:

    • Fusion inhibitors prevent HIV from entering target cells. Drugs of this class bind to the HIV envelope protein gp41, which is involved in viral entry. By blocking the interactions between regions of the gp41 molecule, fusion inhibitors interfere with the conformational change (folding) of the envelope molecule required for fusion with the target cell membrane. Enfuvirtide (ENF) is an FDA-approved fusion inhibitor.

    • Chemokine coreceptor antagonists also prevent the entry of HIV into target cells. They bind to coreceptors on the surface of CD4 cells. By doing so, they block a required step in viral entry. In contrast to drugs from other classes, which act on viral enzymes, coreceptor antagonists bind human proteins. Maraviroc (MVC) is currently the only available medication of this class.

    • Integrase inhibitors bind a viral enzyme known as integrase and interfere with the incorporation of reverse-transcribed HIV DNA into the chromosomes of host cells. Raltegravir (RAL) is an FDA-approved integrase inhibitor.

i. What should be recommended with regard to continuation of medications taken chronically?

Cardiac: Cardiac medications are common in the HIV population given the longer life expectancy and the risk of accelerated cardiovascular disease. Aspirin, beta-blockers, statins, calcium channel blockers, and system vasodilators are used commonly. Most should be continued in the perioperative period. A possible except may be ACE (angiotensin-converting-enzyme) inhibitors, which may exacerbate anesthesia-mediated vasodilatation. IV pentamidine can induce ventricular arrhythmias, and should be continued with caution and appropriate monitoring.

Pulmonary: Bronchodilators and inhaled corticosteroids should be continued as prescribed perioperatively to minimize the risk of bronchospasm and pulmonary complications. Many HIV patients, especially those with advanced disease, are on prophylactic or therapeutic antibiotics to prevent against opportunistic infections such as PCP or MAC; these should also be continued perioperatively. Aerosolized pentamidine can occasionally induce bronchospasm, and should be used with caution in the immediate perioperative period.

Renal: As discussed above, HIV as well as HAART is associated with significant renal dysfunction. Medications used to manage renal dysfunction should be continued perioperatively.

Neurologic: In general, medications used to treat HIV-related neurological disorders should be continued in the perioperative period. The clinician should be aware that many of these medications such as anti-epileptic medications can alter the pharmacokinetics of anesthesia-related medications. Further, there can be synergistic effects between several medications used for neurological conditions such as spasticity and anesthetic sedatives. Caution should be used if neurological medications are held, as these could precipitate a worsening or rebound of symptoms.

Psychiatric: The psychosocial impact of living with HIV/AIDS is often underappreciated. Many patients suffer from depression, anxiety, and other psychological disturbances. Many of these are compounded by neurologic conditions. If possible, psychiatric medications should be continued perioperatively.

j. How to modify care for patients with known allergies -

N/A

k. Latex allergy- If the patient has a sensitivity to latex (eg. rash from gloves, underwear, etc.) versus anaphylactic reaction, prepare the operating room with latex-free products.

N/A

l. Does the patient have any antibiotic allergies.

N/A

m. Does the patient have a history of allergy to anesthesia?

N/A

5. What laboratory tests should be obtained and has everything been reviewed?

No specific guidelines exist for use of routine preoperative laboratory testing in HIV patients. As with most other chronic medical conditions, the clinician should consider the patient’s baseline history and physical exam, and the nature of the surgical procedure. However, given the numerous interactions between HIV, opportunistic infections, and HAART, evaluation of complete blood count, clotting functions, electrolytes, and liver function testing are important to the preoperative assessment of the HIV patient.

Verification of the viral load and CD4+ count is important as this is useful in risk assessment. Advanced HIV infection, especially when accompanied by opportunistic infections and/or malignancies, may complicated the perioperative course and management.

Specific laboratory values of note include:

1. Hemoglobin levels: Anemia may be the part of the chronic nature of HIV, but may also be related to opportunistic infections of bone marrow suppression from HAART (especially the NRTIs). Transfusion thresholds are based on clinical situation including comorbidities, end organ damage, ongoing bleeding, or other signs and symptoms of inadequate oxygen carrying capacity. As patients with HIV have longer life expectancies, comorbid conditions such as cerebrovascular and cardiovascular disease may alter the transfusion threshold.

2. Electrolytes

a. Hyponatremia - as discussed earlier, HIV can be assocated with hyponatremia due to pituitary dysfunction or central nervous system infections. Also this can be indicative of ongoing adrenal insufficiency.

b. Creatinine - creatinine can often ber elevated in the setting of dehydration, especially in patients with chronic diarrhea. Further, due to HIV wasting, serum creatinine may not be indicative of actual renal function due to the lack of muscle mass. Other electrolytes abnormalities such as hypocalcemia and hyperphosphatemia can accompany renal dysfunction.

3. Coagulation panel: Coagulation abnormalites are often associated with liver dysfunction, although these do not become apparent until significant degrees of liver insufficiency occur. These can be as a result of infections (HBV, HCV, CMV) or medications (HAART, anti-epileptics). These can be manifest as ongoing unexplained surgical bleeding, especially after extensive procedurs. Further thrombocytopenia can often accompany HIV, due to bone marrow suppression from HIV or HAART or direct infection of megakaryocytes.

4. Imaging: Preoperative chest x-ray and ECG are generally indicated given the risk of accelerated cardiac disease and ongoing opportunistic infections. Stress tests, echocardiograms, pulmonary function tests, and other diagnostic studies are at clinical discretion as indicated.

5. Other tests: Thyroid function tests, lipid panel, glucose.

Intraoperative Management: What are the options for the anesthetic management and how to determine the best technique?

The approach to the HIV/AIDS patient who presents for surgery should be similar to the that of any patient with a major systemic disease with multiple end-organ involvement (i.e. hypertension, diabetes mellitus). When planning an anesthetic for a patient who has HIV/AIDS, as in any patient with a major illness, a careful review of the disease process and the current status of the patient’s disease and management is vital. HIV infection is a multiorgan disease with complex therapeutic options. A general, neuraxial, regional, or combined anesthetic can be used safely and successfully only after careful assessment of the patient’s status, type of surgery, coexisting disease, medications, and patient preference. Studies have failed to shown a difference in outcome specific to the HIV population.

Neuraxial/regional anesthesia

Regional and neuraxial anesthesia had previously been controversial, with fears that such techniques would allow spread of the virus of the peripheral and central nervous systems. However, these techniques have been used extensively in HIV patients without unique or adverse sequelae. Likely this stems from the fact that central nervous system infection occurs within days of infection, and thus the risk of introducing viral load into the nervous system is unfounded.

Benefits

Related primarily to the general benefits of any neuraxial/regional technique.

  1. Regional anesthesia may be particularly beneficial in limiting parenteral opioids and other medications that can have significant interactions with antiretroviral therapy (i.e. protease inhibitors).

  2. May reduce issues with postoperative delirium or postoperative cognitive decline in those with central nervous system infections, neoplasm, AIDS encephalopathy, or AIDS-related dementia complex.

  3. Provides excellent intraoperative and post-operative pain control, especially with continuous catheter techniques.

  4. Beneficial in parturients for labor and delivery due to excellent analgesia and maternal satisfaction, generally precluding the need for airway management.

  5. Avoids airway management in those with significant amounts of oropharyngeal infection, which can lead to trauma, edema, and bleeding.

  6. Avoids issues with postoperative nausea and vomiting, which can be difficult to control in the setting of HIV, infection, and antiretroviral therapy.

Drawbacks

Related to absolute and relative contraindications for neuraxial/regional anesthesia.

  1. Contraindicated in those with elevated intracranial pressure (i.e., CNS toxoplasmosis, CNS lymphoma).

  2. Relatively contraindicated in the presence of infection.

  3. Many patients are on aspirin and other platelet-inhibitors for accelerated cardiac disease that may preclude the use of neuraxial technique or require advanced planning.

  4. Technical difficulties in patients with severe spasticity.

  5. Patients with baseline neurological deficits and/or peripheral neuropathy can present a unique challenge to the clinician performing a neuraxial or regional technique.

  6. May not be feasible in the delirious or demented patient, as a result of infection or AIDS encephalopathy/dementia-complex.

  7. Coagulopathy can exist in those with significant HIV-related liver dysfunction or thrombocytopenia related to HIV or antiretroviral medications.

  8. Interference with respiratory mechanics (i.e., high spinal, loss of accessory muscles) can be detrimental to those with concomitant pulmonary infections, neoplasm, or significant degrees of myopathy and muscle wasting.

  9. May cause significant hypotension, which can be detrimental in those with accelerated cardiovascular disease.

  10. May not be feasible from surgical standpoint.

Issues to emphasize

  1. Requires careful evaluation of patient’s status, coexisting diseases, and HIV-related complications.

  2. The use of an epidural blood patch is appropriate when indicated to treat post-dural puncture headache. Despite the above-discussed theoretical risk, there are no unique contraindications to this procedure in the HIV-seropositive patient. Although conservative management should be considered initially, there is no evidence to suggest that there are any unique risks of epidural blood patches in the HIV patient.

Benefits

Related primarily to the overall benefits of any general anesthetic.

  1. Provides a secure airway and ability to mechanically ventilate the patient, which may be ideal with compromised respiratory function from infections.

  2. May be ideal for patients with elevated intracranial pressure from infections or neoplasm.

  3. Allows for operative management of delirious or demented patients.

  4. No specific contraindications in the setting of coagulopathy or other multiorgan system dysfunction.

  5. May be better suited to surgical procedure (i.e., laparotomy, prolonged tourniquet time, etc.

  6. Maybe ideal for patients with significant neuropathy, myopathy, orspasticity, which can preclude use of a neuraxial/regional technique.

Drawbacks

Revolve around patient’s underlying comorbid conditions.

  1. Presence of significant pulmonary disease and infection can present challenges for intraoperative gas exchange, bronchospasm, and ability to extubate at the conclusion of the procedure.

  2. Changes in hemodynamics can causesignificant cardiovascular disturbances, especially in light ofaccelerated cardiac disease in the HIV patient.

  3. May or may not further the need for invasive monitoring.

  4. Unclear interaction of anesthetic agents (especially muscle relaxants) in patients with significant myopathy.

  5. Patients with peripheral neuropathy mayhave exacerbation of their symptoms under general anesthesia. The causeis multifactorial, but the clinician should ensure all areas of pressureare padded and protected.

  6. Common medications in the HIV population(antiretroviral, antibiotics, antiepileptic, anti-spasticity) caninteract with both the pharmacokinetics and pharmacodynamics ofanesthetic medications.

  7. Airway manipulation in patients with significant amounts of Candida, herpes,or CMV infection involving the oro- and hypopharynx can experiencesignificant amounts of trauma, bleeding, and edema which may complicateairway management and ability to extubate.

Issues to emphasize

  1. As with neuraxial/regional technique, requires careful evaluation of the patient and patient preference, with particular attention to cardiopulmonary reserve.

  2. Often dictated by the nature of the surgical procedure.

Monitored anesthesia care

Often the ability to perform a monitored anesthesia care depends on the nature of the procedure and the ability of the patient to tolerate the procedure in a sedated fashion. If surgically feasible, this precludes the risks of both general and neuraxial/regional anesthesia. However, one must take into account the overall comorbidities and HIV-related complications, as well as patient and surgical preference. Otherwise, no unique considerations are applicable. A monitored anesthesia care can be performed safely in the HIV-positive patient.

Benefits

  1. Avoids the overall risks of general and neuraxial/regional anesthesia as well as those specific to the HIV population.

  2. Avoids issues with airway manipulation, as discussed above.

  3. Can perform regardless of coagulation status.

  4. Often can be performed regardless of multiorgan system dysfunction.

  5. Generally well tolerated by patients with significant cardiopulmonary compromise.

  6. Avoids complications related to underlying baseline peripheral neuropathy of neurological diseases.

Drawbacks

  1. Often not feasible for a given procedure.

  2. Appropriate levels of sedation may be difficult to achieve, exposing patients to ranges of under- and oversedation, which can lead to larygnospasm, bronchospasm, aspiration, and other pulmonary complications.

  3. May be technically difficult in patients with delirium or dementia related to HIV/AIDS.

  4. May not be feasible in patients with significant degrees of spasticity, myopathy, or neuropathy.

  5. Still requires administration of anesthetic and sedatives, which may be poorly tolerated in those with underlying neurological abnormalities or who have altered pharmacokinetics/pharmacodynamics related to antiretroviral and antibiotic medications.

Issues to emphasize

  1. Requires careful planning and cooperation on behalf of surgeon, anesthesiologist, and patient.

  2. Often not surgically feasible.

6. What is the author's preferred method of anesthesia technique and why?

Based on a thorough evaluation of the literature and clinical experience, general, neuraxial, regional, monitored anesthesia care, or a combination technique can be performed safely in patients with HIV/AIDS. The performance of any of these techniques requires careful thought and consideration of the patient’s clinical status, the degree of immunologic compromise, the presence of opportunistic infections, degree of end-organ dysfunction (related to the virus itself, opportunistic infections, and medications), current medical therapy, as well as other coexisting comorbid conditions, many of which are enhanced by the HIV disease process. The clinician must thoroughly evaluate all of these areas, and with consideration of the surgical issues and patient’s preference, create an appropriate and safe anesthetic plan for each patient.

The goals of anesthesia care in those living with HIV are to provide appropriate and safe anesthesia, analgesia, and amnesia, facilitate the surgical procedure, and attempt to minimize the perioperative risks. As the life expectancy of those living with HIV/AIDS is increasing in the Western world, likely more and more patients will be living with multiple comorbid conditions both related and unrelated to HIV. As with all other chronic, long-term medical conditions, the clinician must take into account the entire clinical picture and create a successful anesthetic technique for the patient with HIV.

Of note, regardless of the type of anesthesia provided, prophylactic antibiotics should be administered to all HIV patients based on the proposed surgical procedure and patient comorbidities. While HIV/AIDS itself presents no changes to established recommendations, patient should continue any preoperative antibiotic regimens in the perioperative period, be it prophylactic (PCP, MAC) or therapeutic (toxoplasmosis).

What are the most common intraoperative complications and how can they be avoided/treated?

Pulmonary complications

Can occur specifically in the AIDS patient with opportunistic lung infections, such as PCP, tuberculosis, or MAC. As these conditions are usually treatable, surgical procedures should be postponed if feasible until improvement of pulmonary status. This decision should be made in light of the patient’s status and urgency of the procedure. Intraoperatively, a neuraxial/regional technique may be preferred. Otherwise, maximize oxygen delivery through altered FiO2 and mechanical ventilation with appropriate amounts of ventilatory pressure and positive end-expiratory pressure (PEEP), generally aiming for low-tidal volume ventilation while preserving adequate gas exchange.

Inhaled or systemic bronchodilators, repeated suction and pulmonary toilet, and bronchoscopy may be needed to enhance pulmonary mechanics and gas exchange.

Cardiac complications

Can occur in all HIV and non-HIV patients, although HIV patients on antiretroviral therapy are at higher risk given accelerated cardiac disease. Perioperative maneuvers to optimize patients are identical to others with significant coronary disease- namely, optimizing myocardial oxygen supply and demand. This can be accomplished by maximizing medical therapy preoperatively, providing hemodynamic stability perioperatively, maintaining an appropriate hemoglobin level, and avoiding tachycardia (as the heart is perfused in diastole), shivering (which can significant increase myocardial oxygen demand), severe pain, and hypo- and hypertension (which can alter coronary perfusion pressure gradients). Invasive monitoring should be established if indicated.

Perhaps the most strategic maneuver is to maintain a strong clinical suspicion of cardiac disease preoperatively in all HIV patients, regardless of age or duration of disease.

Neurological complications

Can be difficult to distinguish in the perioperative period, especially in those patients with preexisting neurological diseases and deficits. The clinician should perform a careful physical exam preoperatively to establish and document any and all neurological deficits, including descriptions of paresthesias, sensory loss, etc. One should establish if there are any signs and symptoms of increased intracranial pressure. Intraoperatively, all areas should be checked, padded, and protected as deemed necessary. Patients with significant myopathy and/or spasticity may require additional time and effort to maintain a neutral position.

The use of muscle relaxants, as discussed previously, should be used with caution in those with underlying muscle wasting, myopathy, or other musculoskeletal disease. Cerebrovascular dynamics should be stable in those with concern for elevated intracranial pressure; any changes should be dealt with in an urgent fashion with elevating the head of bed, hyperventilation, and osmolar diuretic therapy. An arterial line with the transducer zeroed at the level of the external auditory meatus may be beneficial for monitoring cerebral perfusion pressure (MAP – CVP [central venous pressure]/ICP [intracranial pressure).

a. Neurologic

N/A

b. If the patient is intubated, are there any special criteria for extubation?

Extubation criteria for the HIV/AIDS patient are identical to other patients. One must ensure adequate return of muscle function (including possible reversal of muscle relaxants), return of basic airway reflexes, adequate analgesia, hemodynamic stability, and ability to maintain adequate gas exchange, with no surgical precludements to extubation. In patients with significant pulmonary compromise from opportunistic infections, one must ensure gas exchange and pulmonary mechanics are ideal. If the concern exists, consider the need for continued post-operative intubation and mechanical ventilation.

c. Postoperative management

What analgesic modalities can I implement?

Any and all modalities of analgesia are acceptable in the HIV patient. Clinician must be cognizant that HIV patients with neurological disease as well as those on antiretroviral therapy may exhibit atypical responses to analgesics (prolonged or shortened duration). In these patients, alternative modalities (neuraxial, regional, non-opioid medications) should be considered. Again, as previously discussed, neuraxial and regional techniques are acceptable in the HIV population.

What level bed acuity is appropriate?

Postoperative care is determined by the patient’s preoperative and perioperative course. Significant blood loss, difficulties with gas exchange, or neurological issues may warrant intensive care unit (ICU)-level care. Patients with significant cardiac disease undergoing intermediate- to high-risk surgery may warrant ICU-level or telemetry care. Uncomplicated surgical courses in otherwise asymptomatic patients can be managed on general wards.

What are common postoperative complications, and ways to prevent and treat them?

  1. General: As discussed earlier, regardless of the surgical procedure, there is an increase in 6-month postoperative mortality in HIV patient with CD4+ cell count <50 cells/μL. If feasible, consider delaying procedure and infectious disease consultation until a more aggressive antiretroviral therapy can be initiated.

  2. Pulmonary: As discussed previously, HIV/AIDS patients are at a high risk of pulmonary complications independent of the nature of their surgical procedure in the presence of significant lung infection. Postoperatively, patients should continue with aggressive pulmonary toilet (incentive spirometery, bronchodilators, ambulation). If pulmonary status is tenuous, consider postoperative intubation and mechanical ventilation. An arterial line with serial arterial blood gases may be useful perioperatively if significant issues with gas exchange and pulmonary mechanics exist.

    Appropriate antibiotics should be continued in those with known pulmonary infection. HIV, infection, and neoplasm are all associated with the risk of pulmonary embolism.

  3. Cardiac: Given the risk of cardiac disease in this population, cardiac complications are a known risk, especially in intermediate- and high-risk procedures. Postoperative, patients should continue on their preoperative medical therapy if feasible, particularly aspirin, statins, and beta-blockers. Adequate pain control, supplemental oxygen, adequate postoperative hemoglobin levels, avoidance of shivering, large variations in blood pressure, and tachycardia are important in maintaining an adequate balance of myocardial oxygen supply and demand. If any concerns exist for perioperative ischemia, a standard 12-lead ECG and chest x-ray should be obtained.

    If significant, further cardiac workup (cardiac enzymes, echocardiography, cardiology consultation) is warranted, and possible need for invasive monitoring and ICU-level care. Those patients with significant cardiac disease who underwent intermediate- and high-risk procedures may require post-operative telemetry monitoring.

  4. Neurological: As mentioned, HIV patients can have a wide variety of neurological conditions, many undergoing non-neurotherapeutic procedures. With preexisting neurological deficits, central lesions, or neuropathy, patients should be awakened and extubated when deemed appropriate, and a careful neurological examination should be performed, with specific attention to exacerbations of prior deficits or new-onset deficits. General, neuraxial, and regional anesthesia can all cause exacerbations of underlying neurological conditions; the etiology is likely multifactorial. Any changes from preoperative exam should warrant neurological and infectious disease consultation and likely further imaging or diagnostic studies.

    If a patient underwent a neuraxial or regional technique (either single-shot or continuous), serial neurological exams should be performed in a similar fashion to ensure complete resolution of blockade. Patients with elevated intracranial pressure (undergoing non-neurosurgical procedures) should be awaken, extubated, and examined as soon as possible to detect any changes in exam. Any worsening should prompt immediate neurological and neurosurgical consultation and further diagnostic studies.

  5. Psychological: Patients with HIV can suffer from significant delirium and dementia. These can be related to direct neurological consequences of HIV, or in advance stages, infection and AIDS-related dementia complex. Overt dementia may in fact preclude the ability of the patient to provide consent preoperatively. Postoperative delirium and cognitive dysfunction are not uncommon in these circumstances. These are also variable on the nature, extensiveness, and invasiveness of the procedure, as well as the level and duration of hospitalization. Patients should be frequently reoriented during the perioperative periods, and secondary causes of delirium or worsening dementia (such as infection, pain, dehydration) should be addressed. Low doses of antipsychotic medication may be used to alleviate delirium.

  6. Postoperative infections: As occurs with many surgical patients, infections can develop postoperatively. Commonly, these occur at the surgical site, in the lungs, genitourinary system, or implanted hardware. In an HIV-positive patient with low viral loads and adequate CD4+ counts, these can be treated similarly to non-HIV patients. In patients with AIDS, high viral loads, and low CD4+ cell counts, these infections can often be more complicated and cause significant amounts of physiologic derangements. One should consider broader-spectrum antibiotics as well as coverage for organisms unique to the immunocompromised host, such as protozoal and fungal organisms. Infectious disease consultation is likely warranted.

  7. Body fluids exposure: All health care workers can be exposed to body fluids of those infected with HIV at any point. This can include blood, urine, pulmonary secretions, or needle sticks. It is important to highlight the need to observe universal precautions for all patients and all workers in order to minimize any risk of exposure. Should exposure occur, one should immediately cleanse the area with soap and irrigation, and express bleeding into the area if possible with percutaneous exposure. Follow institutional protocols for dealing with body fluid exposure. The anesthesiologist who is exposed in the operating room should immediately call for assistance prior to seeking care in order for another practitioner to continue caring for the patient.

What's the Evidence?

Evron, S, Glezerman, M. "Human immunodeficiency virus: anesthetic and obstetric considerations". Anesth Analg. vol. 98. 2004. pp. 503-511.

Hughes, SC. "HIV and Anesthesia". Anesthesiol Clin N Am. vol. 22. 2004. pp. 379-404.

Mehta, NJ, Khan, IA, Mehta, RN. "HIV-related pulmonary hypertension: Analytic review of 131 cases". Chest. vol. 118. 2000. pp. 1133-41.

Prendergast, BD. "HIV and cardiovascular medicine". Heart. vol. 89. 2003. pp. 793-800.

Fine, DM, Perazella, MA, Lucas, GM, Atta, MG. "Renal disease in patients with HIV Infection: Epidemiology, pathogenesis and management". Drugs. vol. 68. 2008. pp. 963-980.

Gupta, SK, Eustace, JA, Winston, JA. "Guidelines for the management of chronic kidney disease in HIV-infected patients: recommendations of the HIV Medicine Association of the Infectious Diseases Society of America". Clin Infect Dis. vol. 40. 2005. pp. 1559-85.

Cello, JP, Sande, MA, Volberding, PA. "The medical management of AIDS". WB Saunders. 1997. pp. 181-195.

Hughes, SC, Dailey, PA. "Human immunodeficiency Virus and obstetric anesthesia". Anesthesiol Clin N Am. vol. 16. 1998. pp. 397-418.

Tom, DJ, Gulevich, SJ, Shapiro, HM. "Epidural blood patch in the HIV-positive patient: Review of clinical experience". Anesthesiology. vol. 76. 1992. pp. 943-7.

Simpson, DM, Tagliatti, M. "Neurologic manifestations of HIV infection". Ann Int Med. vol. 121. 1994. pp. 769-785.

Olkkola, KT, Palkama, VJ, Neuvonen, PJ. "Ritonavir’s role in reducing fentanyl clearance and prolonging its half-life". Anesthesiology. vol. 91. 1999. pp. 681-5.

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