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Flashcards in Immunity disorders & infections Deck (41)
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1

Zidovudine + corticosteroids 

severe myopathy 

respiratory muscle dysfunction

2

Nucleoside reverse transcriptase inhibitors

considerations

ex: Lemuvidine, Zidovudine (Nucleoside reverse transcriptase inhibitors)

  1. inhibition cytochrome P450 (zidovudine + corticosteroids = severe myopathy including respiratory muscle dysfunction)
  2. Lactic acidosis is a huge issue – may have a lower threshold for getting a blood gas
  3. Nausea, diarrhea, myalgia,
  4. ↑ LFTS, pancreatitis,
  5. peripheral neuropathy (possible nerve injury),
  6. renal toxicity,
  7. marrow suppression,
  8. anemia

3

HIV drug that decreases fentanyl clearance 

Protease inhibitors (ritonavir)

  • inhibition of CYP450 3A4 
    • ↓ fentanyl clearance ~ 67%
      • titrated fentany more conservatively
    • increased effects of versed
  • AVOID: meperidine, amiodarone, diazepam in all pts on PI therapy!

4

Protease inhibitors (ritonavir)

considerations

  1. Hyperlipidemia
  2. glucose intolerance → higher blood glucose levels
  3. abnormal fat distribution
  4. altered LFTs
  5. inhibition of CYP450 3A4 

5

Non-nucleoside analog reverse transcriptase inhibitors

considerations 

  • Delavirdine inhibits cytochrome P450
    • may ↑ concentrations
      • sedatives
      • antiarrhythmics
      • warfarin
      • Ca2+ channel blockers
  • Nevirapine induces cytochrome P450 by 98%!  
    • Make sure you are checking things like NMB

6

Integrase strand transfer inhibitors

considerations

appear well tolerated

7

Chemokine receptor 5 antagonists & entry inhibitors

considerations

interact with midazolam altering clearance & drug effect

8

HAART therapy and anesthesia

institution of HAART within 6 months of anesthesia & surgery actually ↑ M&M

9

Ritonavir (Protease inhibitor) & Interactions with Anesthetic Drugs

  • Midazolam: ↑ effects
    • sedation, confusion, respiratory depression
    • Small carefully titrated IV dosing O.K. (just do it very slowly and carefully- working in very tiny incraments one consents are signed)
  • Fentanyl: ↑ effects
    • sedation, confusion, respiratory depression
    • Start with low dose & titrate to pain
  • Avoid (pronounced effects → life threatening due to prolonged clearance)
    • Meperidine → metabolized to normeperidine → which affects CNS (seizures) even with one dose may end up with a toxic dose
    • Amiodarone (arrhythmias) → E½ life = 29 days - may not always think about this with ACLS but is something to keep in the back of your mind
    • Diazepam → long ½ life

10

sterilization product that destroys HIV 

Na+ hypochlorite

11

HIV and Lab results

  1. CD4 counts
    • low/ominous <200 mm3;
    • high/encouraging >500-700 mm3
    • if low, maybe want them to go and change drug regimen prior to surgery
  2. T lymphocyte counts
    • low/ominous 200 cells/mg
  3. Viral load evaluates therapy efficacy but unclear significance to anesthetic outcome – wont tell us how they will do under anesthesia, drugs will still effect all other systems of these patients
  4. CBC
  5. BMP
  6. coagulation studies
  7. CXR
  8. EKG+/- ECHO
  9. PFTs

12

TB drugs that are hepatotoxic

isonazid

Rifampin

Pyrazinamide

13

TB drugs that are hepatotoxic AND renal toxic and have significant drug interactions

Isoniazid

Rifampin

** these are also the most used**

14

Isoniazid adverse rxn

Hepatotoxicity

peripheral neurotoxicity

possible renal toxicity

drug interactions

15

Rifampin adverse rxn

  • Hepatotoxicity
  • renal toxicity
  • anemia
  • thrombocytopenia
  • gastrointestinal upset
  • drug interactions

16

Pyrazinamide adverse rxn

 

Hepatotoxicity

gastrointestinal upset

arthralgia 

17

Ethambutol adverse rxn

Ocular neuritis

18

when can a TB patient have an elective surgery

  1. 3 negative sputum smears
  2. improving symptoms
  3. clear chest X-ray

! must meet ALL 3 requirements to go to surgery !

19

when do you give antibiotics?

  • normal pt: within 1 hr before surgery
  • redose if surgery > 4 hrs 

20

besides antibiotics how else do you prevent infections

AVOID:

  • Hypothermia 
    • Cold pts develop infections at a much higher rate!
    • They also bleed more!!!
  • Hypocarbia 
    • promotes infection causes vasoconstriction which decreases blood flow
    • make sure you are not hyperventilating the patient
  • Hypoxia
  • hyperoxia 
    • concerning for free radical damage
  • Hyperglycemia
  • Blood transfusions
    •  if you can avoid it is its ideal – they are at higher risk to get an infection

21

Endocarditis prophilaxis - who gets it?

Patients who have:

  • Artificial heart valves
  • Prior history of endocarditis
  • Some congenital cardiac malformations
    • Cyanotic congenital heart disease (birth defects with O2 levels lower than normal), that has not been fully repaired, including children who have had a surgical shunts & conduits, or those with prosthetic device with a repaired
    • A congenital heart defect that's been completely repaired with artificial material or a device for the first six months after the repair procedure

    • Repaired congenital heart disease with residual defects, such as persisting leaks or abnormal flow at or adjacent to a prosthetic patch or prosthetic device

  • Damaged heart valves
  • Hypertrophic cardiomyopathy
  • A cardiac transplant which develops a problem in a heart valve

AND undergoing the following surgeries:

  • Dental or oral with perforation of the oral mucosa likely (dental extractions)
  • Invasive procedures of respiratory tract where respiratory mucosa perforated
    • I.e. Tonsillectomy, adenoids, abscess drainage
  • Procedure involving infection of GI/GU tract, skin/musculoskeletal tissue (not needed with routine procedures; colonoscopy, upper endoscopy, cystoscopy (removal of renal stones) or even bronchoscopy)
  • Cardiac Surgery
  • Hepatobiliary procedures with high risk of bacteremia

22

When and what do you give for endocarditis prophylaxis 

give up to 2 hours after if patient misses pre-procedure

  • Ampicillin 2 g IV (50 mg/kg pediatrics)
  • Cefazolin (Ancef) 1 g IV (50 mg/kg pediatrics)
  • Ceftriaxone (Rocephin) 1 g IV (50 mg/kg pediatrics)

If allergic to penicillins

  • Clindamycin 600 mg IV (20 mg/kg IV pediatrics)

23

Type I allergic rxn

Antigen-Antibody

  • IgE, mast cells, basophils degranulation → anaphylaxis
  • immune-mediated hypersensitivity

24

Type II allergic rxn

Cytotoxic-Complement Activation

  • IgG or IgM binding of the antigen-drug 
  • alternate pathway, kinin or plasmin activation
  • Type II usually manifest as hemolytic anemia, thrombocytopenia, neutropenia

25

Type III allergic rxn

Damage secondary to immune complex formation or deposition

Glomerulonephritis, vasculitis, arthralgias

26

Type IV allergic rxn

T lymphocyte mediated

delayed hypersensitivity type

27

Chemical Mediator allergic rxn

Chemical Mediator with no antigen-antibody reaction

mast cells & basophils activate in a non-immune reaction → anaphylactoid

I.e. MR, meperidine, morphine, etc. 

28

Anaphylactoid Reaction

manifests as histamine release

related to total dose of drug administered & rate of infusion

ex: muscle relaxants, opioids, & protamine

29

Anaphylactoid Reaction prophylaxis 

  • Corticosteroid
  • H1 & H2 receptor antagonist

I.e. decadron, benadryl, ranitidine 

30

Anaphylaxis

  • IgE mediated response
  • life threatening
    • Extravasation of up to 50% of intravascular fluid volume into the EC space possible

  • hypotension 1stsign
  • bronchospasm - seen as increased PIP
  • edema and airway swelling are late signs