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Coexisting 2016 > Immunity disorders & infections > Flashcards

Immunity disorders & infections Flashcards

1
Q

Zidovudine + corticosteroids

A

severe myopathy

respiratory muscle dysfunction

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2
Q

Nucleoside reverse transcriptase inhibitors

considerations

A

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
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3
Q

HIV drug that decreases fentanyl clearance

A

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!
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4
Q

Protease inhibitors (ritonavir)

considerations

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

Non-nucleoside analog reverse transcriptase inhibitors

considerations

A
  • 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
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6
Q

Integrase strand transfer inhibitors

considerations

A

appear well tolerated

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7
Q

Chemokine receptor 5 antagonists & entry inhibitors

considerations

A

interact with midazolam altering clearance & drug effect

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8
Q

HAART therapy and anesthesia

A

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

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9
Q

Ritonavir (Protease inhibitor) & Interactions with Anesthetic Drugs

A
  • 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
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10
Q

sterilization product that destroys HIV

A

Na+ hypochlorite

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11
Q

HIV and Lab results

A
  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
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12
Q

TB drugs that are hepatotoxic

A

isonazid

Rifampin

Pyrazinamide

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13
Q

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

A

Isoniazid

Rifampin

** these are also the most used**

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14
Q

Isoniazid adverse rxn

A

Hepatotoxicity

peripheral neurotoxicity

possible renal toxicity

drug interactions

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15
Q

Rifampin adverse rxn

A
  • Hepatotoxicity
  • renal toxicity
  • anemia
  • thrombocytopenia
  • gastrointestinal upset
  • drug interactions
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16
Q

Pyrazinamide adverse rxn

A

Hepatotoxicity

gastrointestinal upset

arthralgia

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17
Q

Ethambutol adverse rxn

A

Ocular neuritis

18
Q

when can a TB patient have an elective surgery

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

! must meet ALL 3 requirements to go to surgery !

19
Q

when do you give antibiotics?

A
  • normal pt: within 1 hr before surgery
  • redose if surgery > 4 hrs
20
Q

besides antibiotics how else do you prevent infections

A

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
Q

Endocarditis prophilaxis - who gets it?

A

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
Q

When and what do you give for endocarditis prophylaxis

A

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
Q

Type I allergic rxn

A

Antigen-Antibody

  • IgE, mast cells, basophils degranulation → anaphylaxis
  • immune-mediated hypersensitivity
24
Q

Type II allergic rxn

A

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
Q

Type III allergic rxn

A

Damage secondary to immune complex formation or deposition

Glomerulonephritis, vasculitis, arthralgias

26
Q

Type IV allergic rxn

A

T lymphocyte mediated

delayed hypersensitivity type

27
Q

Chemical Mediator allergic rxn

A

Chemical Mediator with no antigen-antibody reaction

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

I.e. MR, meperidine, morphine, etc.

28
Q

Anaphylactoid Reaction

A

manifests as histamine release

related to total dose of drug administered & rate of infusion

ex: muscle relaxants, opioids, & protamine

29
Q

Anaphylactoid Reaction prophylaxis

A
  • Corticosteroid
  • H1 & H2 receptor antagonist

I.e. decadron, benadryl, ranitidine

30
Q

Anaphylaxis

A
  • 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
31
Q

Anaphylaxis: Common Offenders

A
  • Antimicrobial agents
    • PCN → 90% of all allergic reactions & 97% of fatal reactions
  • Anesthetics
    • All anesthetic agents can cause anaphylactic reactions with the exception of ketamine & benzos
    • Thiopental has a low risk, but a very high mortality if they have an anaphylactic reaction
  • Radiocontrast dyes
  • Foods
    • I.e. peanuts
  • Insect venoms
    • Bee allergy
32
Q

Anaphylaxis: Anesthetic agents

A
  • Muscle relaxants
    • 50-60% of intra-op anaphylaxis occurances
    • actually much more likely to be casing than an antibiotic
  • protamine
    • seafood & salmon allergy
    • NPH insulin
  • Induction agents
    • Consider ketamine to prevent reaction in high risk patients
  • Antibiotics (10-15%)
  • Volatile anesthetics
  • Opioids
    • D/t histamine release
  • Local Anesthetics
    • esters more likely than amides
  • Blood → even with crossmatch
    • 3% of patients
  • Dextran/Hetastarch
  • Vascular grafts
    • DIC more than anaphylaxis
  • Latex
    • 15% periop
33
Q

Anaphylaxis: Differential Diagnosis

A
  • Pulmonary embolism
  • Pneumothorax – high peak inspiratory pressure
  • AMI
  • CVA
  • Hemorrhage
  • Aspiration
  • Pulmonary edema
  • Venous Air embolism
  • Vasovagal reaction
  • Medication overdose
  • Asthma → shouldn’t produce immediate cardiovascular collapse
  • Arrhythmia → one of the first signs from the muscle reactants these patients could become very bradycardic → may have a loss of profusion to the coronaries and look like an MI
  • Pericardial tamponade
  • Postextubation stridor
  • Sepsis
34
Q

Anaphylaxis: Signs & Symptoms

A
  • Rapid onset CV collapse often 1st sign → myocardial ischemia & dysrhythmias
  • Hypotension → up to 50% of the ICF moves to ECF secondary to capillary permeability changes + leukotrienes are negative inotropes)
    • this happens within minutes
    • Suspect anaphylaxis with sudden hypotension, +/- bronchospasm, following IV drug administration
  • Bradycardia may occur especially with muscle relaxants
  • Difficult intubation → laryngeal edema (usually this is if it is in the later phase – keep in mind if they have an LMA or are masking you will need to intubate immediately because it will get worse and worse)
  • ↑ PIP or inability to ventilate → bronchospasm
  • Flushing, urticaria

Ketamine → propofol → epi

All could work in severe situation

35
Q

anaphylaxis

most common offending abx

A
  1. β-lactam
    • Penicillin, Amoxicillin, Ampicillin, Meticillin
  2. quinolones
    • Ciprofloxacin, Levofloxacin, Ofloxacin, Moxifloxacin
  3. sulfonamides
  4. vancomycin
36
Q

Anaphylaxis: Prompt Intervention

A
  • Communication (let everyone know → surgeon, additional personnel)
    • should stop the case immediately until stable again
  • Stop administration of likely agent(s)
  • Oxygenation
  • Elevate legs if possible to promote blood flow to central circulation
  • Volume infusion → need at least 10-25 ml/kg
    • Colloids fluids (10 ml/kg) are preferred to crystalloid fluids (colloids may stay in the intravascular space more)
    • Fluids boluses over 20 minutes
37
Q

Anaphylaxis: Pharmacology

A
  • Epinephrine – (always always start with epi but sometimes it does fail)
    • Blocks inflammatory mediator release from sensitized cells
    • Restores cell membrane permeability
    • β-agonist effect = relaxation of bronchial smooth muscle, ↑ BP & ↑ inotropy
      • β2 → bronchodilation, ↓ histamine release from mast cells; also best to reverse bronchospasm
      • β1 → will help heart compensate &↑ inotropy
    • α1 stimulation → vasoconstriction & restore vascular integrity
  • Adult IV: 10 mcg-1 mg titrate q 1-2 minutes
    • Start with 10 mcg then double with each repeated dose
  • Children: 1-10 mcg/kg titrate q 1-2 minutes
38
Q

Anaphylaxis: if resistant to epinephrine

A
  • Glucagon: 1-5 mg bolus + infusion 1-2.5 mg/hr
    • ↑ cAMP promotes inotropic activity and helps with the bronchoconstriction
  • Norepinephrine: 0.05-0.1 mcg/kg/min
    • will not help the bronchospasm situation – but will help in shunting blood to central areas –emergency drug
  • Vasopressin: 2-10 unit bolus + infusion 0.01-0.1 unit/min infusion
    • moves blood to central circulation
39
Q

Anaphylaxis: secondary Pharmacology

A

Not necessarily life saving but will help slow down or stop reaction causing anaphylaxis

  • β2 agonists
    • albuterol if patient is still moving air
  • Histamine antagonism
    • Diphenhydramine (IV)(0.5-1 mg/kg IV) with Ranitidine 50 mg IV → better for prevention than for tx.
      • H1 & H2 need to be blocked together - has the best effect
  • Corticosteroids:
    • Enhances β-effects of other agents
    • Inhibits arachidonic acid release (↓ leukotrienes & prostaglandins)
    • Reduced activation of the complement system
    • Hydrocortisone is favored 250 mg IV (Methylprednisolone also OK 80 mg IV)
    • Children hydrocortisone 50-100 mg & methylprednisolone 2 mg/kg
    • Get them on board as soon as possible - wont see immediate effects
40
Q

Septic Patient - Anesthesia Optimization Goals

A

Delay case if not an absolute emergency

  1. Normal temperature
  2. Normal blood glucose
  3. MAP >65 mmHg
  4. CVP 8-12 mmHg
  5. Urine output adequate
  6. Normalized pH
    • correct metabolic acidosis - Plasmalite or Normasol- better compared to LR and NS because they are right at physiologic pH – it is maintained MUCH easier
  7. Mixed venous O2 Sat >70%
  8. Lower VT 6-8 ml/kg → to prevent barotrauma
  9. PIP < 30 cmH2O
  10. Hgb 7-9 g/dL
  11. Prevent additional infection
41
Q

Septic pt and epiduals

A

Don’t even try

Absolute contraindication to do an epidural anesthesia

  • Especially with hemodynamic instability → patient may not tolerate ↓ SVR
  • Epidural abscess if bacteremic blood introduced into epidural space

Coexisting 2016 (12 decks)

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