Anesthetic Considerations for the HIV+ Patient
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Transcript of Anesthetic Considerations for the HIV+ Patient
Anesthetic Considerations
for the HIV+ Patient
Veronica Y. Amos PhD CRNA
October 2014
Prevalence
In 2011, an estimated 1.1 million persons in the U.S. were living with HIV infection
1 in 6 (15.8%) are unaware they are HIV positive
Incidence
Centers for Disease Control (CDC) estimated that approximately 50,000 people are newly infected with HIV
HIV versus AIDS
HIV: Human Immunodeficiency Virus - a retrovirus that specifically infects several kinds of cells in the human body, the most important is the CD4 T-Lymphocyte
HIV versus AIDS
AIDS: Acquired Immunodeficiency Syndrome - When an individual’s CD4 T-Lymphocyte cell count has fallen below 200, and/or the individual has developed some specific and opportune infections.
HIV Targets T Cells
T cells act as the host that the HIV virus needs in order to replicate
CD4 Receptor Site
CD4 is a protein on the surface of the T cell. HIV’s gp120 antigen is a mirror image of the CD4 protein.
HIV Takes Control
of T Cells
Viral RNA needs to become DNA in order to start the replication process. Reverse transcriptase allows the RNA to borrow material from the cell and to "write backwards" a chain of viral DNA.
CD4 Values
Normal: 600 -1200 cells per cubic mm of blood
Meds not needed: 600-350
Increased risk: 350-200 (meds may be started)
Risk for opportunistic infections: less than 200
Viral Load
This test detects and/or measures the amount (viral load) of RNA of the HIV in the blood
Viral Load
Untreated and uncontrolled HIV viral loads can range as high as one million or more copies/mL. A low viral load is usually between 40 to 200 copies/mL, depending on the type of test used.
Viral Load
A viral load result that reads “undetectable” does not mean that one is cured.
Adverse Drug Effects from Antiretroviral Drugs (ARVs)
1. Mitochondrial dysfunction
2. Metabolic abnormalities
3. Bone marrow suppression
4. Allergic reactions
Interaction of ARVs with Other
DrugsPropofol and NRTIs may both potentially promote mitochondrial toxicity and lactic acidosis and it may be best to avoid propofol “infusions” in patients receiving ARVs
Pharmacokinetic Interactions
Primarily due to liver enzyme induction or inhibition, particularly the CYP450 3A4 enzyme
PIs and NNRTIs are the most commonly implicated group of ARVs in drug interactions. Enzyme induction or inhibition can affect the action of several classes of anesthetic drugs
Opioids
The effects of fentanyl may be enhanced by ritonavir (protease inhibitor) due to both liver enzyme inhibition and induction
Enzyme inhibition reduces fentanyl clearance and enzyme induction increases metabolism to active metabolites such as normeperidine
Benzodiazepines
Saquiniar (PI) can inhibit midazolam’s metabolism
Combination of PI and NNRTIs – excessive sedation
Other DrugsCalcium Channel Blockers may have enhanced hypotensive effects due to enzyme inhibition
Local anesthetics such as lidocaine may have increased plasma levels due to enzyme inhibition
Neuromuscular blocker effects may be prolonged, even from a single dose of vecuronium
Other Drugs
Proton Pump Inhibitors, and to a lesser extent antacids and H2 blockers, may adversely affect the absorption of the PI atazanavir
PIs impair the metabolism of the cardiac drugs amiodarone and quinidine
Preferable
Etomidate, atracurium, remifentanil and desflurane are not dependent on CYP450 hepatic metabolism, and therefore, may be preferable drugs
Blood Transfusions
There is evidence that allogenic blood transfusion in the HIV infected patient can lead to transfusion-related immunomodulation (TRIM) and can result in an increase in HIV viral load
Pain
Pain is common in advanced HIV disease and can be very difficult to treat. The etiology of this pain can be multi-factorial, including opportunistic infections such as herpes simples, peripheral neuropathy and drug-related pain
Organ Involvement
Organ involvement in HIV infection may be a direct consequence of HIV infection because of an opportunistic infection or neoplasm, or related to other causes such as side effects of the medications
Respiratory
Prevalence of underlying pulmonary disease is increased due to the increased risk for bacterial pneumonia and the high prevalence of smoking
Respiratory
Both upper and lower airway may be involved with HIV infection:
- Bronchitis, sinusitis, pneumonia (PCP)
- TB, myobacteria and fungal infections
- Airway obstruction (Kaposi’s sarcoma)
Risks/Recommendations
Risk for postoperative pneumonia is increased
Carefully evaluate for respiratory complications in the peri-operative period: HIV+ patients with active PCP or a history of PCP are at increased risk for a spontaneous pneumothorax
Cardiovascular
Increased prevalence of CAD from metabolic dysfunction due to HIV infection and/or ART
QT prolongation or other cardiac abnormalities may occur in advanced HIV and/or ART (methadone, anti-arrhythmics, PI, antipsychotics)
Cardiovascular
- Dilated cardiomyopathy
- Pericardial effusions
- Endocarditis and valvular lesions
- Acute coronary syndrome
- Vasculitis
- Pulmonary hypertension
Recommendations
Assess for CAD preoperatively
Perform a careful review of preoperative ECG results
Gastrointestinal - Difficulty or pain on swallowing
- Increased gastric emptying times
- Bleeding tendency on airway instrumentation/NGT placement
- Diarrhea with associated electrolyte dysfunction & dehydration
- Hepatobiliary impairment
- Pancreatitis
Hepatic
Increased prevalence of hepatic dysfunction from ART or from preexisting liver disease
Risks/Recommendations
Co-infection with HBV or HCV may predispose to increased bleeding due to coagulopathy or thrombocytopenia
Assess preoperatively and dose anesthetics, antibiotics, and other medications accordingly
RenalIncreased prevalence of renal dysfunction from HIV-associated nephropathy
- Acute and chronic disease
- Drug-induced nephrotoxicity, HTN, & diabetes
- HIV-associated nephropathy
Recommendations
Assess for renal dysfunction preoperatively due to possible impact on dosing, selection of anesthetics, and peri-operative antibiotics
Neurological
- Neurocognitive impairment
- Encephalopathy
- Autonomic neuropathy
- Seizures
Endocrine & Metabolic
- Lipodystrophy (truncal obesity, buffalo hump)
- Raised plasma triglycerides, cholesterol, glucose
- Disorders of the hypothalamic-pituitary-adrenal axis (Cushings/Addisons)
- Hyponatremia due to syndrome of inappropriate antidiuretic hormone or adrenal failure
- Hypo/hyperthyroidism
- Lactic acidosis
Hematological
- Anemia
- Neutropenia with severe immunosuppession
- Thrombocytopenia
- Persistent generalized lymphadenopathy
- Hematological malignancies
- Coagulation abnormalities
Recommendations
Consult with hematologist prior to procedure when platelet count approaches 50,000
MRSA
Community-acquired is more common in MSM than in the general population
Recommendations
Good history of previous MRSA infections
Use vancomycin instead of cefazolin for prophylaxis with a positive history of MRSA
HIV Infected Parturient
The advances in HIV treatment have also brought down the rate of mother-to-child HIV transmission significantly. If the mother takes appropriate medical precautions, including taking HIV drugs, the rate of transmission can be reduced from about 25 percent to below 2 percent. In addition, studies have shown that being pregnant will not make HIV progress faster in the mother
HIV Infected Parturient
HIV infection does not contraindicate the administration of neuraxial anesthesia analgesia during labor and/or for a cesarean section). HIV is a neurotropic virus, and the CNS is infected early in the course of the disease.
HIV Infected Parturient
Vertical transmission is increased when CD4 (T-cell counts) decrease below 400 mL and viral load increases over 1000 copies/mL
Elective C-Sections combined with antiretroviral therapy has reduced vertical transmission to <5%
HIV Infected Parturient
Risk factors for vertical transmission include prolonged preterm rupture of membranes (>4 hrs), chorioamnionitis, presence of STD, lack of maternal antiviral therapy, and obstetrical invasive procedures such as cervical cerclage and amniocentesis
Key Points to Remember
If the HIV patient is on a cocktail and they are told to hold a HIV med before surgery….they need to discontinue them all and restart them all together
Key Points to Remember
Occasionally with surgical intervention there may be a temporary or transient increase, also called a blip, in viral load. In people whose viral load is less than 50 copies, blips are a frequent occurrence and is not associated with a sustained increase in viral load.
Risk for Occupational Transmission of HIV
Percutaneous exposure – approx 0.3%
Mucous membrane exposure – approx 0.09%
Occupational Exposure to HIV
Places you at risk:
Percutaneous injury (needlestick or cut with a sharp object)
Contact of mucous membrane or non-intact skin
Blood, tissue, or other body fluids (cerebrospinal, synovial, pleural, peritoneal, pericardial, and amniotic fluid)
Remember
Just because a source patient has an undetectable serum viral load – it does not eliminate the possibility of HIV transmission or the need for post-exposure prophylaxis (PEP ) & follow-up testing
Recommendations
PEP is recommended
Start PEP medication regimens as soon as possible (within 72 hrs) after occupational exposure & continue for a 4-week duration
PEP should contain 3 (or more) ART drugs that have the fewest side-effects & are best tolerated
Follow-up TestingHIV testing at baseline, 6 weeks, 12 weeks, 6 months post-exposure
Complete blood count, renal and hepatic function tests at baseline and 2 weeks
HIV test results should preferable be given to the exposed healthcare provider at face to face appointments