EHPLE Anesthesia flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

MAC definition

Minimum alveolar concentration at 1 atm that prevents movement in 50% of patients in response to a standard surgical stimulus; a measure of volatile anesthetic potency.

Oxygen content formula

CaO2 = (1.34 × hemoglobin × oxygen saturation) + (0.003 × PaO2); dissolved oxygen contributes little to total content at normal hemoglobin.

Local anesthetic mechanism

Weak bases block voltage-gated sodium channels from inside the axon, preventing depolarization; inflamed acidic tissue reduces the uncharged fraction and slows onset.

Closing capacity

Closing volume plus residual volume; it rises with age and exceeds functional residual capacity in supine adults, causing airway closure and shunt.

RCRI components

Revised Cardiac Risk Index: ischemic heart disease, heart failure, cerebrovascular disease, insulin-treated diabetes, creatinine >2 mg/dL, and high-risk surgery; each scores one point.

STOP-BANG score

Screening tool for obstructive sleep apnea: snoring, tiredness, observed apnea, hypertension, BMI >35, age >50, neck circumference >40 cm, and male sex.

ASA fasting guidelines

Clear liquids 2 hours, breast milk 4 hours, infant formula and nonhuman milk 6 hours, light meal 6 hours, and fatty or fried meal 8 hours before anesthesia.

Metformin perioperative

Generally continued through surgery; held if contrast dye or significant renal dysfunction is present because of lactic acidosis risk.

Difficult airway predictors

Mallampati III–IV, thyromental distance <6 cm, mouth opening <3 cm, limited cervical extension, and obesity suggest difficult laryngoscopy.

Succinylcholine contraindications

Hyperkalemia, burns or denervation beyond 24–48 hours, malignant hyperthermia susceptibility, and pseudocholinesterase deficiency; risk of fatal hyperkalemia or prolonged paralysis.

Capnography confirmation

Sustained waveform capnography confirms tracheal intubation; it is the standard and should be used with bilateral breath sounds and chest rise.

RSI technique

Rapid sequence induction uses a rapidly acting induction agent plus succinylcholine or rocuronium 1.2 mg/kg with cricoid pressure to reduce aspiration risk.

Oxygen flush valve

Delivers 35–75 L/min directly to the breathing circuit, bypassing the vaporizer; can cause barotrauma if used during inspiration.

Pulse oximetry limitations

Unreliable with poor perfusion, motion, methemoglobin, and carboxyhemoglobin; relies on differential absorption of red and infrared light.

Soda lime function

Absorbs carbon dioxide via an exothermic reaction; color change from white to violet indicates exhaustion but is unreliable, so CO2 monitoring is preferred.

Oxygen analyzer check

Should read 21% in room air and near 100% with a full oxygen circuit; a low reading indicates a hypoxic mixture.

Propofol induction

Dose 1.5–2.5 mg/kg IV; causes hypotension and apnea and has no analgesic effect; rapid onset and offset.

Spinal anesthesia

Typically uses hyperbaric bupivacaine 0.75% 1.5–3 mL; block level depends on baricity, patient position, and dose.

Epidural test dose

3 mL of lidocaine 1.5% with epinephrine 1:200,000; a heart rate rise >20 bpm suggests intravascular injection.

Interscalene block

Reliably anesthetizes the shoulder but spares the ulnar nerve and causes ipsilateral phrenic nerve palsy in most patients.

Malignant hyperthermia

Presents with rising end-tidal CO2, tachycardia, masseter spasm, and hyperthermia; treat with dantrolene 2.5 mg/kg IV and stop triggering agents.

LAST treatment

Local anesthetic systemic toxicity: perioral numbness, tinnitus, seizures, and cardiac arrest; treat with 20% lipid emulsion 1.5 mL/kg bolus.

Anaphylaxis under anesthesia

Presents as hypotension, bronchospasm, and rash; epinephrine 10–100 mcg IV boluses is first-line, with fluid resuscitation.

Sudden ETCO2 drop

Suggests pulmonary embolism, venous air embolism, or circuit disconnection; assess and act immediately with hemodynamic support.

PONV risk factors

Female sex, nonsmoking, history of PONV, and opioid use; multimodal prophylaxis uses ondansetron, dexamethasone, and droperidol.

Opioid respiratory depression

Presents with decreasing respiratory rate and sedation; naloxone 0.04–0.4 mg IV titrated is the antidote.

Multimodal analgesia

Combines acetaminophen, NSAIDs, local anesthetics, and opioids to reduce opioid requirements and side effects.

ERAS principles

Enhanced recovery after surgery emphasizes early mobilization, early oral intake, opioid-sparing analgesia, and regional techniques.

OSA perioperative risk

Patients have increased sensitivity to opioids and anesthetics; use CPAP, regional techniques where possible, and extended monitoring.

Aortic stenosis anesthesia

Patients are preload-dependent and prone to hypotension; maintain sinus rhythm, preload, and afterload.

Informed consent

Requires capacity, disclosure of risks and alternatives, and voluntary agreement; it is a process, not a signature alone.

WHO surgical checklist

Includes sign-in, time-out, and sign-out phases; it reduces surgical morbidity and mortality through structured communication.