Immunity and Sepsis Flashcards
(41 cards)
1
Q
Zidovudine + corticosteroids
A
severe myopathy
respiratory muscle dysfunction
2
Q
Nucleoside reverse transcriptase inhibitors
considerations
A
- inhibition cytochrome P450 (zidovudine + corticosteroids can = severe myopathy including respiratory muscle dysfunction)
- Lactic acidosis is a huge issue – may have a lower threshold for getting a blood gas
- Nausea, diarrhea, myalgia,
- ↑ LFTS, pancreatitis,
- peripheral neuropathy (possible nerve injury),
- renal toxicity,
- marrow suppression,
- anemia
3
Q
HIV drug that decreases fentanyl clearance
A
Protease inhibitors (ritonavir)
inhibition of CYP450 3A4
(↓ fentanyl clearance ~ 67%)
titrated fentany more conservatively
4
Q
Protease inhibitors (ritonavir)
considerations
A
- Hyperlipidemia
- glucose intolerance → higher blood glucose levels
- abnormal fat distribution
- altered LFTs
- inhibition of CYP450 3A4
5
Q
Non-nucleoside analog reverse transcriptase inhibitors
considerations
A
- Delavirdine inhibits cytochrome P450
- may ↑ concentrations
- sedatives
- antiarrhythmics
- warfarin
- Ca2+ channel blockers
- may ↑ concentrations
- Nevirapine induces cytochrome P450 by 98%!
- Make sure you are checking things like NMB
6
Q
Integrase strand transfer inhibitors
considerations
A
appear well tolerated
7
Q
Chemokine receptor 5 antagonists & entry inhibitors
considerations
A
interact with midazolam altering clearance & drug effect
8
Q
HAART therapy and anesthesia
A
institution of HAART within 6 months of anesthesia & surgery actually ↑ M&M
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 sighned)
- Fentanyl: ↑ effects
- sedation, confusion, respiratory depression
- Start with low dose & titrate to pain
-
Avoid (pronounced effects → life threateningàdue 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
Q
sterilization product that destroys HIV
A
Na+ hypochlorite
11
Q
HIV and Lab results
A
- CD4 counts
- low/ominous
- high/encouraging >500-700 mm3
- if low, maybe want them to go and change drug regimen prior to surgery
- T lymphocyte counts
- low/ominous 200 cells/mg
- 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
- CBC
- BMP
- coagulation studies
- CXR
- EKG+/- ECHO
- PFTs
12
Q
TB drugs that are hepatotoxic
A
isonazid
Rifampin
Pyrazinamide
13
Q
TB drugs that are hepatotoxic AND renal toxic and have significant drug interactions
A
Isoniazid
Rifampin
** these are also the most used**
14
Q
Isoniazid adverse rxn
A
Hepatotoxicity
peripheral neurotoxicity
possible renal toxicity
drug interactions
15
Q
Rifampin adverse rxn
A
Hepatotoxicity
renal toxicity
anemia
thrombocytopenia
gastrointestinal upset
drug interactions
16
Q
Pyrazinamide adverse rxn
A
Hepatotoxicity
gastrointestinal upset
arthralgia
17
Q
Ethambutol adverse rxn
A
Ocular neuritis
18
Q
when can a TB patient have an elective surgery
A
- 3 negative sputum smears
- improving symptoms
- 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
Type III allergic rxn
Damage secondary to **immune complex formation** or deposition
**Glomerulonephritis**, **vasculitis**, **arthralgias**
26
Type IV allergic rxn
**T lymphocyte** mediated
## Footnote
**delayed hypersensitivity type**
27
Chemical Mediator allergic rxn
Chemical Mediator with **no antigen-antibody reactio**n
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**
31
Anaphylaxis: Common Offenders
* **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
Anaphylaxis: Anesthetic agents
* **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
Anaphylaxis: Differential Diagnosis
* 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
Anaphylaxis: Signs & Symptoms
* 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
## Footnote
Ketamine → propofol → epi
All could work in severe situation
35
anaphylaxis
most common offending abx
1. β-lactam
2. quinolones
3. sulfonamides
4. vancomycin
36
Anaphylaxis: Prompt Intervention
* **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
Anaphylaxis: Pharmacology
* **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 revers bronchospasm
* **β1** → will help **heart** compensate
* **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
Anaphylaxis: if resistant to epinephrine
* **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
Anaphylaxis: secondary Pharmacology
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
Septic Patient - Anesthesia Optimization Goals
**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
10. Hgb **7-9 g/dL**
11. Prevent additional infection
41
Septic pt and epiduals
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
