Perioperative and cardiac surgical ICU

Caring for the surgical patient in ICU: safe theatre handover and early complications, malignant hyperthermia and LAST, post-CABG and valve care, bleeding, tamponade and arrest after cardiac surgery (CALS), epicardial pacing, and frailty and obesity — with Indian practice notes.

6 topics

01
Post-operative handover and early complications
Taking a safe theatre-to-ICU handover, the first 30 minutes after arrival, and a systematic approach to the common early post-operative problems: hypoxaemia, hypotension, oliguria, hypothermia, pain, PONV, delirium and myocardial injury after non-cardiac surgery (MINS).
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02
Malignant hyperthermia and local anaesthetic systemic toxicity
Two rare but lethal anaesthetic emergencies that can present in theatre, recovery or ICU: malignant hyperthermia (stop triggers, dantrolene 2.5 mg/kg, cool, treat hyperkalaemia) and LAST (airway, seizure control, 20% lipid emulsion, modified ACLS).
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03
Post-CABG and valve surgery care
The first 24 hours after cardiac surgery: arrival bundle, haemodynamic and metabolic targets, early extubation, recognising low cardiac output syndrome versus vasoplegia, post-operative AF, transfusion thresholds and valve-specific points.
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04
Bleeding, tamponade and cardiac arrest after cardiac surgery
Distinguishing surgical from coagulopathic bleeding, a targeted (viscoelastic-guided) correction bundle, when to call for re-exploration, recognising post-operative tamponade, and the cardiac-surgery-specific arrest protocol (CALS/STS: three shocks, pace, resternotomy within 5 minutes).
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05
Epicardial pacing wires and temporary pacing
How to read and set a temporary pacing box after cardiac surgery: modes (AAI, VVI, DDD, asynchronous), output and sensitivity thresholds, daily checks, troubleshooting failure to capture or sense, and safe wire removal.
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06
Frailty and obesity in the surgical ICU patient
Assessing frailty with the Clinical Frailty Scale and using it to shape goals and post-operative care, and the practical ICU management of the obese surgical patient: weight scalars for drug dosing, airway and ventilation, OSA, VTE and pressure care.
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Drugs in this module

Doses written for this module's context. The same drug may read differently in another module.

Dantrolene sodium

Ryanodine receptor (RYR1) antagonist; skeletal muscle relaxant

Indications: Malignant hyperthermia crisis
Adult dose: 2.5 mg/kg IV bolus as fast as possible; repeat 1 mg/kg (or 2.5 mg/kg per MHAUS) every 5–10 min until hypermetabolism resolves; usual total up to 10 mg/kg, more if still needed. Then 1 mg/kg every 4–6 h (or 0.25 mg/kg/h infusion) for 24 h to prevent recrudescence.
Preparation (India): Classic vials: 20 mg dantrolene + 3 g mannitol, each reconstituted with 60 mL sterile water (not saline/dextrose) — slow to dissolve; assign several people. Newer 250 mg/5 mL formulation (Ryanodex) dissolves fast but is rarely available in India. MHAUS recommends 36 × 20 mg vials stocked where triggering agents are used.
Cautions: Thrombophlebitis (large vein); muscle weakness; avoid with calcium-channel blockers (hyperkalaemia, myocardial depression). Mannitol content causes diuresis.
Monitoring: ETCO₂, temperature, K⁺, CK, myoglobinuria, ABG, urine output.

Lipid emulsion 20% (intravenous fat emulsion)

Lipid sink / metabolic rescue

Indications: Local anaesthetic systemic toxicity (LAST) with significant cardiovascular or neurological toxicity
Adult dose: >70 kg: 100 mL bolus over 2–3 min, then 200–250 mL over 15–20 min. ≤70 kg: 1.5 mL/kg (lean body weight) bolus over 2–3 min, then 0.25 mL/kg/min. If still unstable: repeat bolus once or twice and/or double infusion rate. Upper limit about 12 mL/kg.
Preparation (India): 20% soya-based lipid emulsions (100 mL, 250 mL, 500 mL bags) are available as parenteral nutrition products; keep one in theatre and in the LAST kit. Propofol is NOT a substitute.
Cautions: Lipaemia interferes with lab tests; pancreatitis, fat overload with excess doses.
Monitoring: ECG, BP, neurological status; continue monitoring ≥4–6 h after a cardiovascular event (≥2 h after seizure only).

Protamine sulfate

Heparin reversal agent

Indications: Reversal of residual heparin after cardiopulmonary bypass ('heparin rebound') or heparin overdose
Adult dose: 1 mg neutralises ~100 units of heparin. After CPB, top-up doses typically 25–50 mg slow IV guided by ACT/heparin assay; give slowly (≤5 mg/min); single dose ≤50 mg.
Preparation (India): 10 mg/mL ampoules (5 mL = 50 mg) commonly available.
Cautions: Hypotension, anaphylaxis, catastrophic pulmonary hypertension (risk: fish allergy, protamine-insulin use, vasectomy, prior exposure). Excess protamine is itself anticoagulant.
Monitoring: ACT, aPTT, BP, pulmonary artery pressure if available.

Tranexamic acid

Antifibrinolytic

Indications: Prevention/treatment of bleeding in cardiac surgery and post-operative haemorrhage
Adult dose: Cardiac surgery protocols vary: commonly 10–30 mg/kg IV load with or without infusion; for post-operative bleeding 1 g IV over 10 min (may repeat). Reduce in renal impairment.
Preparation (India): 500 mg/5 mL ampoules widely available and cheap.
Renal / hepatic: Renally excreted: reduce dose in AKI.
Cautions: Seizures (dose-related, especially high-dose regimens in open-chamber surgery), thrombosis.
Monitoring: Drain output, neurological status.

Desmopressin (DDAVP)

Vasopressin V2 analogue; releases von Willebrand factor/factor VIII

Indications: Bleeding with platelet dysfunction (antiplatelet drugs, uraemia, von Willebrand disease) after cardiac surgery
Adult dose: 0.3 mcg/kg IV in 50 mL saline over 20–30 min (single dose; tachyphylaxis with repeats).
Preparation (India): 4 mcg/mL ampoules; availability variable.
Cautions: Hypotension if given fast, hyponatraemia, thrombosis.
Monitoring: BP, sodium.

Noradrenaline (norepinephrine)

Alpha-1 > beta-1 agonist vasopressor

Indications: Vasoplegia after cardiopulmonary bypass; post-operative hypotension with adequate filling
Adult dose: 0.05–0.5 mcg/kg/min IV infusion titrated to MAP (often 65–80 mmHg after cardiac surgery per surgeon).
Preparation (India): 2 mg/2 mL ampoules (check base vs bitartrate labelling); 4 mg in 50 mL = 80 mcg/mL; 8 mg in 50 mL = 160 mcg/mL.
Cautions: Extravasation; excess afterload on a failing LV; mesenteric/digital ischaemia at high doses.
Monitoring: Arterial line, lactate, urine output, cardiac output where measured.

Adrenaline (epinephrine)

Alpha and beta agonist; inotrope/vasopressor

Indications: Low cardiac output syndrome after cardiac surgery; anaphylaxis; cardiac arrest (with modified dosing after cardiac surgery)
Adult dose: Infusion 0.01–0.2 mcg/kg/min. Arrest after cardiac surgery: CALS/STS advise against routine 1 mg boluses; if used, consider small doses (e.g. 50–100 mcg) only after shocks/pacing/resternotomy are being addressed.
Preparation (India): 1 mg/mL ampoules; common infusion 4 mg in 50 mL (80 mcg/mL).
Cautions: Tachyarrhythmias, lactic acidosis (beta-2 effect), hyperglycaemia; rebound hypertension and graft/suture bleeding with bolus doses.
Monitoring: ECG, arterial line, lactate, glucose.

Vasopressin

V1 receptor agonist

Indications: Vasoplegia after cardiopulmonary bypass refractory to noradrenaline
Adult dose: 0.01–0.04 units/min IV infusion (fixed dose, not weight-based).
Preparation (India): 20 units/mL ampoules; 20 units in 50 mL = 0.4 units/mL (0.03 units/min = 4.5 mL/h).
Cautions: Digital, mesenteric and coronary ischaemia at higher doses; hyponatraemia.
Monitoring: MAP, peripheral perfusion, sodium.

Methylene blue (methylthioninium chloride)

Guanylate cyclase / nitric oxide synthase inhibitor

Indications: Rescue for catecholamine-refractory vasoplegia after cardiopulmonary bypass
Adult dose: 1–2 mg/kg IV over 20–60 min; may be followed by an infusion in some protocols.
Preparation (India): 1% (10 mg/mL) ampoules; availability varies.
Cautions: Contraindicated in G6PD deficiency (haemolysis) — relevant in India; serotonin syndrome with SSRIs/SNRIs/MAOIs/linezolid; falsely low SpO₂ readings; blue-green urine.
Monitoring: SpO₂ (unreliable transiently), methaemoglobin, haemolysis screen.

Dobutamine

Beta-1 agonist inotrope

Indications: Low cardiac output syndrome after cardiac surgery
Adult dose: 2.5–10 mcg/kg/min IV infusion (up to 20 mcg/kg/min).
Preparation (India): 250 mg/20 mL ampoule; 250 mg in 50 mL = 5,000 mcg/mL.
Cautions: Tachyarrhythmias, AF, hypotension from beta-2 vasodilation, myocardial oxygen demand.
Monitoring: Heart rate and rhythm, cardiac index, lactate, ScvO₂.

Milrinone

Phosphodiesterase-3 inhibitor (inodilator)

Indications: Low cardiac output with high SVR or pulmonary hypertension/RV dysfunction after cardiac surgery
Adult dose: 0.125–0.5 mcg/kg/min IV; loading dose (50 mcg/kg) usually omitted because of hypotension.
Preparation (India): 10 mg/10 mL ampoule; 10 mg in 50 mL = 200 mcg/mL.
Renal / hepatic: Renally cleared: reduce in AKI (long half-life).
Cautions: Hypotension (often needs noradrenaline), arrhythmias.
Monitoring: MAP, arrhythmias, renal function.

Amiodarone

Class III antiarrhythmic

Indications: Post-operative AF (rhythm control or prophylaxis); VF/pVT after defibrillation
Adult dose: AF: 150–300 mg (or 5 mg/kg) IV over 20–60 min, then 900 mg over 24 h (≤1.2 g/day). Arrest: 300 mg IV after the third shock (CALS: after three stacked shocks).
Preparation (India): 150 mg/3 mL ampoules; dilute in 5% dextrose; central line preferred for infusions >2 mg/mL.
Cautions: Hypotension, bradycardia, QT prolongation, phlebitis; drug interactions (warfarin, digoxin).
Monitoring: ECG, QTc, BP, LFTs and thyroid function with prolonged use.

Metoprolol

Cardioselective beta-1 blocker

Indications: Rate control and prevention of post-operative AF after cardiac surgery (if not hypotensive or low output)
Adult dose: IV 2.5–5 mg over 2 min, repeat every 5 min to 15 mg. Oral 12.5–50 mg twice daily (restart early after cardiac surgery).
Preparation (India): Injection 1 mg/mL (5 mL); tablets 25/50 mg (tartrate) and extended-release succinate.
Cautions: Hypotension, low cardiac output, bradycardia/heart block, bronchospasm.
Monitoring: HR, BP, cardiac output.

Atropine

Antimuscarinic

Indications: Symptomatic bradycardia (if no pacing wires or while setting up pacing)
Adult dose: 0.5–1 mg IV, repeat every 3–5 min to a maximum of 3 mg.
Preparation (India): 0.6 mg/mL ampoules.
Cautions: Ineffective in denervated (transplanted) heart; tachycardia, urinary retention, delirium.
Monitoring: HR, rhythm.

Isoprenaline (isoproterenol)

Non-selective beta agonist

Indications: Bradycardia/heart block when pacing is unavailable or failing; bridge to temporary pacing
Adult dose: 0.5–10 mcg/min IV infusion titrated to heart rate.
Preparation (India): Ampoule strengths vary (e.g. 2 mg/mL or 0.2 mg/mL) — check label; e.g. 2 mg in 50 mL = 40 mcg/mL (1 mcg/min = 1.5 mL/h).
Cautions: Tachyarrhythmias, hypotension (beta-2 vasodilation), myocardial ischaemia.
Monitoring: ECG, BP.

Ondansetron

5-HT3 antagonist antiemetic

Indications: Prophylaxis and treatment of PONV
Adult dose: 4 mg IV at end of surgery or for treatment; may repeat once after 6 h (use a different class if prophylaxis failed).
Preparation (India): 2 mg/mL ampoules; 4/8 mg tablets and orally disintegrating forms.
Cautions: QT prolongation, constipation, headache.
Monitoring: QTc if other QT-prolonging drugs.

Paracetamol (acetaminophen)

Non-opioid analgesic/antipyretic

Indications: Multimodal post-operative analgesia
Adult dose: 1 g IV/PO every 6 h (max 4 g/day); 15 mg/kg if <50 kg; max 3 g/day in hepatic risk, malnutrition or chronic alcohol use.
Preparation (India): IV 1 g/100 mL bottles; 500/650 mg tablets.
Renal / hepatic: Reduce in hepatic impairment, low body weight.
Cautions: Hepatotoxicity; IV dosing errors in low-weight patients.
Monitoring: LFTs if prolonged high dose.

6 topics

Post-operative handover and early complications

Malignant hyperthermia and local anaesthetic systemic toxicity

Post-CABG and valve surgery care

Bleeding, tamponade and cardiac arrest after cardiac surgery

Epicardial pacing wires and temporary pacing

Frailty and obesity in the surgical ICU patient

Drugs in this module

Module references (20)