EDAIC Part I flashcards

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

MAC definition

Minimum alveolar concentration at one atmosphere that prevents movement in response to a standard surgical stimulus in 50 percent of patients. It is a measure of potency and inversely correlates with lipid solubility.

Oxygen delivery equation

DO2 equals cardiac output multiplied by arterial oxygen content. Arterial content is 1.34 times haemoglobin times saturation plus 0.003 times PaO2, so anaemia and low output both reduce delivery.

Train-of-four ratio

Ratio of the fourth to the first evoked twitch in response to four supramaximal stimuli. A ratio above 0.9 indicates adequate recovery of neuromuscular function, whereas 0.7 leaves significant residual block.

Malignant hyperthermia trigger

Volatile anaesthetic agents and suxamethonium trigger uncontrolled skeletal muscle calcium release through a ryanodine receptor defect. Earliest signs are rising end-tidal carbon dioxide, tachycardia, and masseter spasm before hyperthermia appears.

Dantrolene dosing

Malignant hyperthermia is treated with dantrolene 2.5 mg/kg intravenously, repeated until symptoms resolve up to a total of 10 mg/kg. It inhibits ryanodine receptor calcium release and must accompany cooling and 100 percent oxygen.

Lipid emulsion rescue

Intravenous 20 percent lipid emulsion 1.5 mL/kg bolus followed by infusion is the antidote for local anaesthetic systemic toxicity, particularly bupivacaine-induced refractory ventricular arrhythmias and cardiac arrest.

Laryngospasm treatment

Remove the stimulus, apply 100 percent oxygen with continuous positive airway pressure, deepen anaesthesia with propofol, then give suxamethonium 0.5 to 1 mg/kg if obstruction persists. Negative-pressure pulmonary oedema is a complication.

Berlin ARDS definition

Acute onset within one week of a known insult, bilateral opacities not explained by cardiac failure, and PaO2/FiO2 of 300 mmHg or less with PEEP at least 5 cmH2O. Severity is graded mild, moderate, or severe.

Sepsis-3 definition

Life-threatening organ dysfunction caused by a dysregulated host response to infection, operationalised as a SOFA score increase of at least two points. qSOFA identifies risk but is not diagnostic of sepsis.

Lung-protective ventilation targets

Tidal volume 6 mL/kg predicted body weight, plateau pressure 30 cmH2O or less, and driving pressure 15 cmH2O or less. These settings reduce ventilator-induced lung injury and mortality in acute respiratory distress syndrome.

Prone positioning indication

In moderate to severe ARDS with PaO2/FiO2 below 150 mmHg, prone positioning for at least 16 hours daily improves oxygenation and reduces mortality. It recruits dorsal lung and reduces ventral strain.

SOFA score components

Six organ systems scored: respiration, coagulation, liver, cardiovascular, central nervous system, and renal. Each scores 0 to 4, and a rise of two or more points defines sepsis in suspected infection.

Vasopressor first line

Noradrenaline is the first-line vasopressor in septic shock, targeting mean arterial pressure of 65 mmHg. Vasopressin is added to reduce noradrenaline requirement, and dobutamine is used for persistent myocardial depression.

Apfel PONV score

Four risk factors: female sex, non-smoker, history of postoperative nausea or motion sickness, and postoperative opioids. Each adds roughly 20 percent risk, guiding multimodal prophylaxis with dexamethasone, ondansetron, and droperidol.

Revised cardiac risk index

Six predictors of perioperative cardiac events: ischaemic heart disease, heart failure, cerebrovascular disease, insulin-treated diabetes, creatinine above 177 micromol/L, and high-risk surgery. Three or more indicate elevated risk.

Functional capacity threshold

Four metabolic equivalents, equivalent to climbing a flight of stairs, permits most surgery without further cardiac testing. Poor functional capacity warrants cardiopulmonary exercise testing or pharmacological stress imaging.

Starling equation

Fluid flux equals the filtration coefficient times the difference between hydrostatic and oncotic pressure gradients, modified by the reflection coefficient. In sepsis, glycocalyx damage lowers the reflection coefficient and worsens oedema.

P50 value

The partial pressure of oxygen at which haemoglobin is 50 percent saturated, normally about 26.6 mmHg. A right shift from acidosis, hypercapnia, or pyrexia reduces affinity and improves tissue oxygen unloading.

Propofol induction dose

1.5 to 2.5 mg/kg intravenously in a healthy adult. It causes hypotension through venodilation and myocardial depression, so the dose is reduced by 30 to 50 percent in hypovolaemia, elderly, or ASA III-IV patients.

Ketamine in shock

1 to 2 mg/kg intravenously preserves airway tone and sympathetic drive, making it useful in hypovolaemic or septic shock. It is a bronchodilator but raises secretions and can cause emergence phenomena.

Suxamethonium hyperkalaemia risk

Depolarising blockade releases potassium; dangerous rises occur in burns after 24 hours, denervation injuries, prolonged immobility, and critical illness. Bradycardia occurs with repeat dosing, and intraocular pressure rises transiently.

Morphine metabolites

Morphine is glucuronidated to morphine-6-glucuronide, an active metabolite that accumulates in renal failure and causes delayed sedation and respiratory depression. Fentanyl is about 100 times more potent and has no active metabolites.

Naloxone limitation

Naloxone reverses opioid effects but has a shorter half-life than most opioids, so renarcotisation can occur. It is titrated in small 40 microgram boluses and followed by infusion or repeat dosing with monitoring.

CICO management

Cannot intubate, cannot oxygenate is declared after failed intubation and supraglottic rescue. Emergency front-of-neck access with a scalpel-bougie-tube technique is performed rather than repeating unsuccessful attempts.

Anaphylaxis under anaesthesia

Common triggers are neuromuscular blockers, antibiotics, chlorhexidine, and latex. Treat with titrated adrenaline 50 microgram boluses, 20 mL/kg fluid, and stop the trigger; send mast cell tryptase within one hour and at 24 hours.

Adrenaline anaphylaxis dose

Intramuscular adrenaline 0.5 mg of 1:1000 solution into the anterolateral thigh for general anaphylaxis. Under anaesthesia, titrated intravenous boluses of 50 micrograms are used because the patient is already monitored and cannulated.

Cricoid pressure evidence

Sellick manoeuvre is used in rapid sequence induction to reduce aspiration risk but has weak evidence for benefit and can worsen laryngoscopic view. It is released if ventilation or intubation is impeded.

Rapid sequence induction

Pre-oxygenation followed by a fast-acting induction agent and suxamethonium or high-dose rocuronium, with avoidance of positive pressure ventilation before intubation. Used when aspiration risk is high, such as full stomach or obstruction.

Sugammadex reversal

A modified gamma-cyclodextrin that encapsulates rocuronium and vecuronium, reversing deep block within minutes. Dose is 2 mg/kg for train-of-four count 2, 4 mg/kg for post-tetanic count 1 to 2, and 16 mg/kg for immediate rescue.

Neostigmine ceiling effect

Neostigmine inhibits acetylcholinesterase but has a ceiling effect and cannot reverse deep block. It is given only when train-of-four count is at least 2, with glycopyrrolate to prevent bradycardia and secretions.

Post-dural puncture headache

Occurs after dural puncture, worse upright and relieved lying flat. Conservative treatment includes fluids, caffeine, and bed rest; an epidural blood patch of 15 to 20 mL autologous blood is definitive and effective.