PGIM MD Anaesthesiology flashcards

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

Difficult mask ventilation predictors

MOANS: poor Mask seal, Obesity or airway Obstruction, Age over 55, No teeth, and Stiff lungs. Each factor increases difficulty; two or more warrant an alternative airway plan before induction.

CICO emergency management

When intubation and oxygenation both fail, declare cannot-intubate-cannot-oxygenate, call for help, and perform emergency front-of-neck access with a scalpel-bougie-tube or cannula technique without further intubation attempts.

Suxamethonium dose and duration

1 to 1.5 mg/kg intravenously gives intubating conditions in 45 to 60 seconds and lasts 5 to 10 minutes. It is hydrolysed by plasma cholinesterase, so atypical genotypes prolong block.

Sugammadex reversal dose

Sugammadex 16 mg/kg reverses rocuronium given at 1.2 mg/kg for rapid sequence induction; 2 mg/kg reverses moderate block and 4 mg/kg reverses deep block, guided by train-of-four monitoring.

Laryngospasm treatment

Remove the stimulus, apply 100% oxygen with continuous positive airway pressure and jaw thrust, and deepen anaesthesia. If it persists, give propofol 0.5 to 1 mg/kg or suxamethonium 0.5 to 1 mg/kg intravenously.

Maximum lidocaine dose

Lidocaine 3 mg/kg without adrenaline and 7 mg/kg with adrenaline in adults. For a 70 kg patient this is 210 mg plain or 490 mg with adrenaline, so a 2% solution (20 mg/mL) allows 10.5 or 24.5 mL.

Lipid emulsion for LAST

Give 20% lipid emulsion 1.5 mL/kg bolus followed by 0.25 mL/kg/min infusion for local anaesthetic systemic toxicity. Stop injection, oxygenate, control seizures, and avoid vasopressin, calcium channel blockers and beta-blockers.

Epidural adrenaline test dose

15 micrograms of adrenaline in the test dose produces a rise in heart rate within 20 to 40 seconds if the catheter is intravascular. Aspiration alone is unreliable because vessels collapse on suction.

Epidural blood patch

Inject 15 to 20 mL of autologous blood at the level of dural puncture for post-dural puncture headache. It is effective in about 70 to 90 percent of patients after one patch and can be repeated.

Septic shock criteria

Sepsis with vasopressor requirement to maintain mean arterial pressure at least 65 mmHg and serum lactate above 2 mmol/L despite adequate fluid resuscitation, according to the Sepsis-3 definition.

ARDS Berlin definition

Acute onset within one week, bilateral opacities not fully explained by effusion, collapse or nodule, not primarily cardiac, and PaO2/FiO2 ratio 300 or less with PEEP at least 5 cmH2O.

Lung-protective ventilation settings

Tidal volume 6 mL/kg predicted body weight, plateau pressure 30 cmH2O or less, and PEEP titrated to oxygenation. These settings reduce mortality in acute respiratory distress syndrome and are used in most ventilated patients.

Hyperkalaemia with ECG changes

Give calcium gluconate 10% 10 to 30 mL for membrane stabilisation, then insulin 10 units with 25 g glucose, then nebulised salbutamol. Dialysis is required for refractory or renal failure cases.

Oxygen delivery equation

DO2 equals cardiac output multiplied by arterial oxygen content, where CaO2 equals 1.34 times haemoglobin times arterial saturation plus 0.003 times PaO2. Normal delivery is about 1000 mL/min.

Alveolar gas equation

PAO2 equals FiO2 times (barometric pressure minus 47) minus PaCO2 divided by 0.8. At sea level on room air with PaCO2 5.3 kPa, alveolar oxygen is about 13.3 kPa.

Oxyhaemoglobin curve right shift

Affinity falls and oxygen unloading increases with raised temperature, raised CO2, increased 2,3-DPG and acidosis. Fetal haemoglobin and carboxyhaemoglobin shift the curve left, increasing affinity.

Cerebral blood flow autoregulation

Normal cerebral blood flow is about 50 mL/100 g/min and is autoregulated between mean arterial pressures of 60 and 160 mmHg. Flow changes about 4 percent per mmHg of PaCO2 within 20 to 80 mmHg.

Closing capacity significance

Closing capacity exceeds functional residual capacity in supine adults around age 45 and in infants. This causes airway closure, shunt and hypoxaemia during anaesthesia and in the postoperative period.

Propofol induction profile

1.5 to 2.5 mg/kg intravenously produces hypnosis in 30 to 60 seconds. It causes hypotension and apnoea, has antiemetic effect at low dose, and has a short context-sensitive half-time with infusion.

Volatile agent MAC values

Minimum alveolar concentration is about 2.0 percent for sevoflurane, 1.15 percent for isoflurane and 6.0 percent for desflurane. MAC falls with pregnancy, hypothermia, opioids and increasing age.

Hagen-Poiseuille flow relationship

Flow is proportional to the fourth power of radius and inversely proportional to length and viscosity. Halving a tube's radius reduces laminar flow sixteen-fold, explaining resistance in narrow airway devices.

Half-life from volume and clearance

Elimination half-life equals 0.693 times volume of distribution divided by clearance. A large volume of distribution or low clearance prolongs half-life and delays offset of drug effect.

Pulse oximetry limitations

Two wavelengths, 660 and 940 nm, distinguish oxyhaemoglobin and deoxyhaemoglobin. Readings are falsely normal or misleading with carboxyhaemoglobin, methaemoglobin, poor perfusion, motion and nail polish.

One-lung ventilation hypoxaemia

Check tube position first, apply PEEP 5 cmH2O to the dependent lung, and consider continuous positive airway pressure to the non-dependent lung or intermittent two-lung ventilation. Keep tidal volume 4 to 6 mL/kg.

Carotid endarterectomy anaesthesia goals

Maintain mean arterial pressure at or above baseline to preserve cerebral perfusion. Regional cervical plexus block allows awake neurological monitoring, and hypotension and hypercarbia should be avoided.

Protamine reversal of heparin

Give 1 mg protamine per 100 units of heparin. Rapid administration can cause hypotension, bradycardia, pulmonary hypertension and anaphylactoid reactions, so give slowly with monitoring.

Bariatric surgery drug dosing

Dose most anaesthetic drugs by lean body weight rather than total body weight. Suxamethonium and neostigmine are dosed by total body weight. Use ramped position and opioid-sparing multimodal analgesia.

Magnesium sulphate in pre-eclampsia

Loading dose 4 g intravenously over 20 minutes followed by 1 g per hour infusion prevents eclampsia. Monitor reflexes, respiratory rate and urine output, and have calcium gluconate available for toxicity.

Paediatric tracheal tube size

Uncuffed tube internal diameter equals age divided by 4 plus 4; cuffed tube equals age divided by 4 plus 3.5. The narrowest point is the cricoid ring in young children.

Paediatric maintenance fluids

The 4-2-1 rule gives 4 mL/kg/h for the first 10 kg, 2 mL/kg/h for the next 10 kg, and 1 mL/kg/h thereafter. Use isotonic crystalloid and avoid routine glucose-containing solutions.

Neonatal resuscitation ratio

If heart rate remains below 60 per minute after effective ventilation with 100% oxygen, start chest compressions at a ratio of 3 compressions to 1 breath, reassessing heart rate every 60 seconds.

Postoperative apnoea in ex-premature infants

Infants born prematurely are at risk of postoperative apnoea until about 60 weeks postmenstrual age. Admit for monitoring with apnoea alarms and caffeine prophylaxis where local protocol indicates.