Immunity & Infections Flashcards

Question

Anaphylaxis: Anesthetic agents

Answer 1

1. **Opioids** → D/t histamine release 2. **Local Anesthetics** →esters more likely than amides 3. **Induction agents** → * Consider **ketamine** to prevent reaction in high risk patients 4. **Muscle relaxants** * **50-60%** of intra-op anaphylaxis occurances * actually much more likely to be casing than an antibiotic 5. **Volatile anesthetics** 6. **Antibiotics** (**10-15%**) → * Penicillin **90%** of all allergic reactions + **97%** of fatal reactions 7. **Blood** → even with crossmatch (**3**% of patients) 8. **Dextran/Hetastarch** 9. **protamine** * **seafood** & **salmon** allergy * **NPH** insulin 10. **Vascular grafts** → DIC more than anaphylaxis 11. **Latex** → 15% periop

Answer 2

(first think...what could cause or be a manifestation of **hypotension**) 1. **Arrhythmia** → **Bradycardia** → hypotension → decreased coronary profusion 2. May look like an **MI** (ST changes?) 3. **CVA** 4. **Hemmorage** (may also cause hypotension) 5. **Vasovagal reaction** * **** (anything that decreases venous return, uterine manipulation, SVC compression 6. **Pericardial tamponade** (Then think anything that couls cause **decrease O₂** or **increaseCO₂**) 1. **Pulmonary embolism** 2. **Pneumothorax** (high peak inspiratory pressure) 3. **Asthma** → shouldn’t produce immediate cardiovascular collapseAspiration 4. **Pulmonary edema** 5. **Postextubation stridor** (Then the others that dont quite fit!) 1. **Venous Air embolism** 2. **Medication overdose** 3. **Sepsis**

Answer 3

* Flushing, urticaria (often missed d/t drapes) * Rapid onset **CV collapse** often 1st sign → * myocardial **ischemia** & **dysrhythmias** * **Hypotension** → up to **50%** of the **intravascular** fluid moves to **extracellular** fluid 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 **later** but if they have an LMA/ or masking you will need to **intubate** **immediately** because it will get worse) * **↑ PIP** or **inability** **to** **ventilate** → **bronchospasm** * first measure = **↑ inhaled anesthetics** * could use: **Ketamine** → **propofol** → **epi** ## Footnote All could work in severe situation

Answer 4

1. **_Most common offenders include:_** * β-lactam (PCN, cephalosporins) * quinolones * sulfonamides * vancomycin 2. **_Prior to administration_** * look at patients skin for pre-existing **rash** or skin condition * If they develop a rash = may be a reaction to abx 3. **Patients with a history of allergy** (food, asthma, drugs) 1. have **increased** **incidence** of anapylaxis 2. may be **genetic** predisposition to increased **IgE** antibodies 4. **If someone has a PCN allergy:** * they are **3-4x** more likely to have an allergic reaction to **ANY** **drug**! 5. **NKDA**/**previous** **unevetntful** exposure does not mean no allergy * Often **one** exposure needed to make IgE * It is the **subsequent** exposure that is the problem ## Footnote

Answer 5

* **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**

Answer 6

* **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

Answer 7

* **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

Answer 8

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

Answer 9

**Delay case if not an absolute emergency** 1. Normal temperature 2. Normal blood glucose 3. MAP **\>65 mmHg** 4. CVP **8-12 mmHg** 5. Hgb **7-9 g/dL** 6. Urine output adequate 7. **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 8. Mixed venous O₂ Sat **\>70%** 9. Lower VT **6-8 ml/kg** → to prevent barotrauma 10. PIP **\<30** 11. Prevent additional infection

Answer 10

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

Answer 11

**Sepsis Definition** 1. Sepsis is a large term representing a **spectrum of diseases** where there are **pathogenic microorganisms in the body** 2. Severity depends on **organ** involvement and the extent of systemic inflammatory resposnse _Anesthesia management:_ **Intervascular fluid and hemodynamic status guides management** 1. **_Pre-op focus_** 1. ABG, Vital Signs, mental status, vasopressors, sedation, pain management 2. Need at least **2 large bore IVs** 3. Make sure **PRBCs** are in OR refrigerator (physically look!) 2. **_Monitors_** 1. Standard + 2. **A-line PRE induction** 3. **CVP/PA** (lower threshold if **TEE** available)

Answer 12

**Goal = maintain SVR** 1. No specific ideal technique 2. agents that will help maintain SVR * Etomidate (conster the risk of adrenal supression) * Ketamine 3. Consider length of immobility before administering **Succinycholine** d/t possible hyerkalemian

Answer 13

Goal is to maintain SVR 1. No Ideal technique 2. **Fluid resuscitation** (bolus) 1. crystalloind 500-1000mL 2. colloid 300-500mL 3. **Inotropic or vasoconstricter support** if needed * Epi * **Norepi** (first on algorythm **0.05-0.5 mcg/kg/min**) * Dopamine * Dobutamine * Vasopressin 4. Consider **hydrocortisone** for **unresponsive** **shock**

Answer 14

they will likely remain intubated and go to the ICU