Analgo-Sedation First Principle
Treat pain before sedation. Assess analgesia using CPOT (Critical-care Pain Observation Tool) or NRS before initiating or escalating sedation. Undertreated pain drives agitation and inadvertent extubation.
PICS Prevention & Sedation Bundles
ABCDEF Bundle — PICS Prevention
- A — Assess, prevent & manage pain using validated scales (CPOT/NRS/BPS) before initiating sedation
- B — Both SAT & SBT — Spontaneous Awakening Trials (SAT) paired with Spontaneous Breathing Trials (SBT) daily
- C — Choice of sedation/analgesia — Minimise benzodiazepines; prefer dexmedetomidine or propofol; target lightest effective sedation depth
- D — Delirium monitoring & management — Assess using CAM-ICU or ICDSC. Non-pharmacological measures first (reorientation, sleep hygiene, mobilisation)
- E — Early exercise & mobility — Active/passive physiotherapy even during mechanical ventilation reduces ICU-acquired weakness
- F — Family engagement & empowerment — Reduce isolation; family presence reduces delirium incidence
Sedation Assessment Scales
RASS — Richmond Agitation-Sedation Scale
| Score | Label | Description |
|---|---|---|
| +4 | Combative | Violent, danger to staff |
| +3 | Very agitated | Pulls tubes, aggressive |
| +2 | Agitated | Non-purposeful movement, fights ventilator |
| +1 | Restless | Anxious but movements not aggressive |
| 0 | Alert & calm | Target for most awake patients |
| -1 | Drowsy | Sustained eye-opening >10s to voice |
| -2 | Light sedation | Brief eye-opening to voice — target range for ventilated patients |
| -3 | Moderate sedation | Movement to voice, no eye-opening |
| -4 | Deep sedation | No response to voice; movement to physical stimulation |
| -5 | Unarousable | No response to voice or physical stimulation |
Target RASS -2 to 0 for most ventilated patients. Deep sedation (≤-3) associated with increased delirium, ventilator days and PICS.
SAS — Sedation-Agitation Scale
| Score | Label | Description |
|---|---|---|
| 7 | Dangerous agitation | Pulls at ETT, thrashing, climbing out of bed |
| 6 | Very agitated | Requires restraint; biting ETT |
| 5 | Agitated | Anxious, calmed by voice |
| 4 | Calm & cooperative | Calm, awake, follows commands |
| 3 | Sedated | Difficult to arouse, awakens to verbal |
| 2 | Very sedated | Arouses to physical stimuli but does not communicate |
| 1 | Unarousable | Minimal response to stimuli |
SAS target: 3–4 for ventilated patients. SAS 4 is equivalent to RASS 0.
Opioid Analgesics in Critical Care
Opioids — Analgo-Sedation Foundation
Morphine Opioid — mu agonist
- Active metabolite: morphine-6-glucuronide (M6G) — accumulates in renal failure causing prolonged sedation and respiratory depression
- Avoid in renal impairment (CrCl <30 mL/min) — use fentanyl or hydromorphone instead
- Histamine release — may cause hypotension; IV bolus should be given slowly
Fentanyl Opioid — short-acting
- Preferred opioid in renal failure — no active metabolites
- Hepatic metabolism via CYP3A4 — dose reduction in hepatic failure
- Highly lipophilic — context-sensitive half-life increases significantly with prolonged infusions (accumulation in fat stores)
- Dose: 25–100 mcg/h IV infusion; bolus 25–50 mcg IV PRN
Remifentanil Ultra-short acting opioid
- Metabolised by non-specific plasma and tissue esterases — organ-independent elimination
- Ultra-short context-sensitive half-life (3–5 min) regardless of infusion duration
- Infusion only — no bolus dosing; rapid offset allows neurological assessment without sedation hold
- Particularly useful for neurological ICU patients requiring frequent GCS assessment
- Tolerance and opioid-induced hyperalgesia may develop with prolonged use
Hydromorphone Opioid — semi-synthetic
- Alternative to morphine in renal failure (metabolites less clinically significant than M6G)
- 5–7× more potent than morphine
- Dose: 0.2–0.6 mg IV q2-4h PRN or 0.2–0.5 mg/h infusion
Sedative Agents
Sedative Medications
Propofol GABA-A agonist
- Mechanism: potentiates GABA-A receptor — hypnotic, amnestic, no analgesic effect
- Short-acting with rapid onset and offset — suitable for short-term sedation and neuro assessment
- 30% lipid emulsion vehicle — monitor triglycerides (at least every 48h during infusion)
- Provides approximately 1.1 kcal/mL — account for in nutritional calculations
- Dose: 0.5–4 mg/kg/h (light sedation); max 4–5 mg/kg/h
Propofol Infusion Syndrome (PRIS)
Risk factors: >5 mg/kg/h for >48h, high doses in children, concurrent catecholamines/corticosteroids. Presentation: metabolic acidosis, rhabdomyolysis, hyperkalaemia, cardiac failure (new right bundle branch block, ST changes), lipaemia, hepatomegaly, renal failure. Monitor CK and triglycerides. Fatal if unrecognised — stop infusion immediately if suspected.
Dexmedetomidine Alpha-2 agonist
- Mechanism: selective alpha-2 adrenoceptor agonist (locus coeruleus) — sedation without respiratory depression
- Produces cooperative sedation — patients arousable and able to follow commands
- Reduces delirium incidence compared to benzodiazepines (MENDS, SEDCOM trials)
- Analgesic-sparing and opioid-sparing properties
- Useful for ventilator weaning and facilitating SAT/SBT
- Dose: 0.2–1.5 mcg/kg/h; loading dose optional (1 mcg/kg over 10 min — frequently omitted to avoid haemodynamic instability)
Side Effects
Bradycardia and hypotension are the most clinically significant adverse effects. Use with caution in patients with pre-existing bradycardia, heart block, or haemodynamic instability. Monitor HR and BP closely during initiation and dose titration.
Midazolam GABA-A agonist — benzodiazepine
- Mechanism: positive allosteric modulator of GABA-A receptor — sedation, anxiolysis, amnesia, anticonvulsant
- Long context-sensitive half-life — accumulates with prolonged infusions; particularly in elderly, obese, and hepatic impairment
- Active metabolite: alpha-hydroxy-midazolam — accumulates in renal failure
- Increases delirium incidence compared to non-benzodiazepine agents
- Role: short-term procedural sedation, status epilepticus, as adjunct when other agents insufficient
- Preferred benzodiazepine in ICU when benzodiazepines are indicated (versus lorazepam — propylene glycol vehicle toxicity in high-dose infusions)
Key Principle
Vasopressors increase SVR (systemic vascular resistance) via alpha-1 receptor activation. Inotropes increase myocardial contractility via beta-1 receptor activation. MAP target in septic shock: ≥65 mmHg (higher targets may be considered in chronic hypertension).
First-Line & Adjunct Vasopressors
Noradrenaline (Norepinephrine)
First-line vasopressorSeptic shockCentral line required
- Mechanism: alpha-1 >> beta-1 agonist — potent vasoconstriction, mild positive inotropy
- Dose: 0.01–3.0 mcg/kg/min IV infusion; start at 0.05–0.1 mcg/kg/min and titrate to MAP ≥65 mmHg
- Preparation: typically 4 mg/50 mL (80 mcg/mL) or 8 mg/50 mL (160 mcg/mL) in 5% dextrose
- Central venous access required — peripheral extravasation causes tissue necrosis
- Supported by Surviving Sepsis Campaign as vasopressor of first choice in septic shock
- Reflex bradycardia may occur at high doses
Extravasation Warning
Must be administered via a dedicated central venous catheter lumen. Peripheral administration is a temporary emergency measure only. Phentolamine (alpha-blocker) is the antidote for extravasation necrosis.
Vasopressin (ADH Analogue)
Adjunct to noradrenalineNoradrenaline-sparing
- Mechanism: V1 receptor agonist on vascular smooth muscle — vasoconstriction independent of adrenergic receptors
- Fixed dose: 0.03–0.04 units/min — no dose titration (unlike catecholamines)
- Added when noradrenaline dose exceeds 0.25 mcg/kg/min to achieve noradrenaline-sparing effect
- VASST trial: vasopressin + noradrenaline vs noradrenaline alone — no mortality difference overall; trend to benefit in less severe septic shock
- Reduces splanchnic blood flow at higher doses — monitor for mesenteric ischaemia
- Also used in vasodilatory shock post-cardiac surgery
Adrenaline (Epinephrine)
Anaphylaxis / Cardiac arrestRefractory shock
- Mechanism: alpha-1 + beta-1 + beta-2 agonist — potent vasoconstriction and inotropy
- First-line agent in anaphylaxis: IM 0.5 mg (1:1000) — not IV outside cardiac arrest/ICU
- Cardiac arrest: 1 mg IV every 3–5 min (1:10,000)
- ICU infusion: 0.01–1.0 mcg/kg/min for refractory septic or cardiogenic shock
- Arrhythmogenic at higher doses — increases myocardial oxygen demand
Lactic Acidosis — Lactate Unreliable
Adrenaline causes Type B lactic acidosis by stimulating aerobic glycolysis. Serum lactate is an unreliable marker of tissue perfusion and resuscitation adequacy when adrenaline is infused. Do not use lactate clearance as a resuscitation endpoint.
Dobutamine
Inotrope — cardiogenic shockLow CO states
- Mechanism: beta-1 > beta-2 agonist — positive inotrope and chronotrope; peripheral vasodilation (beta-2)
- Dose: 2.5–20 mcg/kg/min IV infusion; titrate to cardiac output/CI target
- Increases contractility and reduces afterload — improves CI in cardiogenic shock
- Side effects: tachycardia (dose-dependent), may worsen hypotension (vasodilation) in volume-depleted patients
- Often combined with noradrenaline in mixed cardiogenic/distributive shock
- Tachyphylaxis may develop after 72–96h of continuous infusion
Dopamine
Dose-dependent effectsLess favoured in sepsis
- Low dose (1–5 mcg/kg/min): predominantly dopaminergic (DA1/DA2) — historically used for "renal protection" — not supported by evidence
- Moderate dose (5–10 mcg/kg/min): beta-1 dominant — inotropic effect
- High dose (>10 mcg/kg/min): alpha-1 dominant — vasoconstriction
- SOAP II trial: dopamine associated with higher rate of arrhythmias and increased 28-day mortality in cardiogenic shock subgroup vs noradrenaline
- Generally not preferred over noradrenaline in septic shock per Surviving Sepsis Campaign
Milrinone
PDE-3 inhibitorRight heart failure
- Mechanism: phosphodiesterase-3 inhibitor — increases intracellular cAMP → positive inotropy + vasodilation (inodilator)
- Does not act on adrenergic receptors — useful when beta-receptors are downregulated (chronic heart failure, post-cardiac surgery)
- Pulmonary vasodilation — reduces RV afterload; preferred in right ventricular failure, pulmonary hypertension
- Loading dose: 50 mcg/kg over 10 min (often omitted to avoid hypotension); maintenance 0.375–0.75 mcg/kg/min
- Renally cleared — dose reduction required in renal impairment
- Significant hypotension risk — requires careful volume status optimisation
Vasopressor Dose Calculator
Interactive Vasopressor Dose Calculator
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NMB Monitoring Requirement
All patients receiving neuromuscular blocking agent (NMBA) infusions must have continuous sedation (target RASS -4 to -5) and analgesia. Administer NMBA only after confirming adequate sedation — paralysed patients cannot communicate distress. Monitor with train-of-four (TOF) stimulation.
Depolarising NMBAs
Suxamethonium (Succinylcholine)
RSI agentDepolarising
- Mechanism: nicotinic ACh receptor agonist at NMJ — depolarising block; fasciculations occur prior to paralysis
- Dose for RSI: 1.5 mg/kg IV (some protocols 1.0–2.0 mg/kg)
- Onset: 45–60 seconds; Duration: 5–10 minutes (short-acting due to hydrolysis by plasma pseudocholinesterase)
- Ideal for RSI — rapid onset, brief duration, rapid recovery if intubation fails
HYPERKALAEMIA — Absolute Contraindications
Suxamethonium causes potassium release (~0.5 mEq/L normal rise). In the following conditions, massive hyperkalaemia (potentially fatal cardiac arrest) may occur — AVOID suxamethonium:
Burns (>24–48h post-injury, risk persists weeks to months) | Prolonged immobility / muscle disuse | Denervation injuries (spinal cord injury, stroke, peripheral nerve injury — upregulation of extrajunctional ACh receptors) | Crush injuries | Prolonged ICU stay with muscle wasting | Rhabdomyolysis | Neuromuscular diseases (muscular dystrophies)
Non-Depolarising NMBAs
Non-Depolarising Agents — Comparison
Rocuronium Modified RSI agent
- RSI dose: 1.2 mg/kg IV — onset 60–90 seconds (slower than suxamethonium at standard dose but comparable at high dose)
- Standard intubating dose: 0.6 mg/kg; maintenance 0.1–0.2 mg/kg bolus PRN or 0.3–0.6 mg/kg/h infusion
- Duration at RSI dose: 60–90 minutes
- Preferred alternative to suxamethonium when suxamethonium is contraindicated
- Reversible with sugammadex at any depth of block — key advantage for RSI
- Hepatically eliminated — prolonged duration in liver failure; dose reduction required
Vecuronium Intermediate-acting
- Dose: 0.1 mg/kg IV intubating dose; maintenance 0.01–0.02 mg/kg/h infusion
- Duration: 25–40 minutes at intubating dose
- Hepatic and renal elimination — accumulates in organ failure
- Active metabolite (3-desacetylvecuronium) accumulates in renal failure causing prolonged block
- Reversed by neostigmine (partial reversal) or sugammadex
Cisatracurium Organ-independent elimination
- Dose: 0.15–0.2 mg/kg IV intubating dose; maintenance 1–3 mcg/kg/min infusion
- Elimination: Hofmann degradation (spontaneous temperature- and pH-dependent chemical breakdown) + ester hydrolysis — completely organ-independent
- Preferred NMBA for patients with renal and hepatic failure — no dose adjustment required
- Preferred agent for prolonged ICU paralysis (ARDS protocol)
- Laudanosine metabolite: CNS excitatory — clinically irrelevant at therapeutic doses
ICU Indications for NMB Infusions
Clinical Indications & Evidence
Severe ARDS (P:F ratio <150)
- ACURASYS trial (2010): Early 48h cisatracurium infusion improved 90-day mortality in severe ARDS (P:F <150) vs placebo
- ROSE trial (2019): Cisatracurium with light sedation — no mortality benefit vs light sedation alone; questioned routine NMB use in ARDS
- Current practice: Consider early 48h NMB in severe ARDS with P:F <150 if patient-ventilator dyssynchrony persists despite optimised sedation
- Reduces ventilator-induced lung injury (VILI) by preventing effort-induced injury
Other ICU Indications
- Refractory intracranial hypertension — prevents ICP spikes from agitation/coughing
- Status asthmaticus — reduces dynamic hyperinflation and barotrauma
- Status epilepticus (refractory) — facilitates EEG-guided management (NMB abolishes motor activity; EEG monitoring mandatory)
- Therapeutic hypothermia / targeted temperature management — prevents shivering
- Facilitation of prone positioning in ARDS
- Tetanus with severe muscle spasms
Monitoring & Reversal
Train-of-Four (TOF) Monitoring
- Apply peripheral nerve stimulator to ulnar nerve (adductor pollicis) or facial nerve
- 4 supramaximal stimuli at 2 Hz — count twitches visible
- 4/4 twitches: no significant block
- 3/4 twitches: ~75% receptors blocked
- 2/4 twitches: ~80% receptors blocked
- 1/4 twitches: ~90% receptors blocked
- 0/4 twitches: >95% receptors blocked — deep block
- ICU infusion target: 1–2 twitches (90–95% block)
Reversal Agents
Sugammadex Cyclodextrin encapsulator
- Mechanism: encapsulates rocuronium/vecuronium — forms stable complex, removed from NMJ, excreted renally
- Reverses any depth of block including deep block (advantage over neostigmine)
- RSI rescue dose (immediate reversal): 16 mg/kg IV
- Deep block reversal (1 twitch): 4 mg/kg IV
- Moderate block reversal (2 twitches): 2 mg/kg IV
- Does not reverse suxamethonium or cisatracurium
Neostigmine + Atropine/Glycopyrrolate Anticholinesterase
- Mechanism: inhibits acetylcholinesterase — increases ACh at NMJ
- Only reliably reverses moderate block (≥2 twitches) — cannot reverse deep block
- Dose: neostigmine 0.04–0.07 mg/kg + glycopyrrolate 0.2 mg per 1 mg neostigmine (to prevent muscarinic effects: bradycardia, bronchospasm, excessive secretions)
- Does not reverse sugammadex-encapsulated rocuronium
Antibiotic Stewardship Principles
De-escalation strategy: initiate broad-spectrum coverage empirically, then narrow based on culture and sensitivity results. Avoid prolonged broad-spectrum therapy. Use procalcitonin (PCT) to guide duration — target PCT-guided discontinuation when PCT falls >80% from peak or absolute value <0.5 mcg/L.
Pharmacokinetic / Pharmacodynamic Principles
Time-Dependent Killing
- Efficacy depends on %T>MIC — time free drug concentration exceeds MIC
- Drug classes: beta-lactams (penicillins, cephalosporins, carbapenems), vancomycin, clindamycin
- Optimisation strategy: extended infusion or continuous infusion (not higher doses)
- Beta-lactam extended infusion (e.g., meropenem 1g over 3h q8h vs 30 min q8h) increases %T>MIC and clinical cure rates
- In critical illness: augmented renal clearance (ARC) can dramatically reduce drug exposure — monitor and dose accordingly
Concentration-Dependent Killing
- Efficacy depends on AUC:MIC or Peak:MIC
- Drug classes: aminoglycosides (Cmax:MIC), fluoroquinolones (AUC:MIC), metronidazole
- Aminoglycosides: once-daily extended interval dosing (ODD) achieves high Cmax:MIC — superior bactericidal efficacy, reduced nephrotoxicity vs multiple daily dosing
- ODD dosing using Hartford nomogram — plot 8/12/18h post-dose level
- Prolonged post-antibiotic effect (PAE) — bacterial suppression continues after drug level falls below MIC
Broad-Spectrum ICU Antibiotics
Beta-Lactam Antibiotics
Piperacillin-Tazobactam (Tazocin) Broad-spectrum penicillin + BLI
- Coverage: gram-negative (including Pseudomonas), gram-positive, anaerobes
- ICU indications: HAP/VAP, intra-abdominal infections, complicated UTI, febrile neutropenia
- Dose: 4.5g q6h IV (or 4.5g q8h extended infusion over 4h — PK/PD optimisation)
- Renal dose adjustment required (CrCl <20 mL/min)
- BLISS trial: piperacillin-tazobactam not non-inferior to meropenem for ESBL bloodstream infections — use carbapenems for confirmed ESBL
Meropenem / Imipenem-Cilastatin Carbapenem
- Broadest-spectrum beta-lactams — reserved for resistant organisms
- Indications: ESBL producers, Pseudomonas aeruginosa, Acinetobacter, severe intra-abdominal/polymicrobial infections
- Meropenem: 1–2g q8h IV; extended infusion (over 3h) recommended for resistant organisms or ARC
- Imipenem: associated with seizures at higher doses — use meropenem for CNS infections
- Preserve carbapenems — de-escalate to narrower agents once cultures available
Anti-MRSA Agents
Vancomycin Glycopeptide — MRSA first-line
- Mechanism: inhibits cell wall synthesis (binds D-Ala-D-Ala terminus)
- Indications: MRSA infections, gram-positive infections in beta-lactam allergy, C. difficile (oral vancomycin)
- Dosing: weight-based loading dose (25–35 mg/kg); maintenance guided by AUC/MIC monitoring
- Modern TDM: AUC-guided dosing (AUC/MIC target 400–600 mg·h/L) recommended over trough-only monitoring (ASHP/IDSA/SIDP 2020 guidelines)
- Traditional trough target: 15–20 mg/L — associated with nephrotoxicity without improved efficacy
- Nephrotoxicity: synergistic with aminoglycosides, loop diuretics, contrast — monitor SCr, urine output
- Infusion-related: Red Man Syndrome (rate-dependent histamine release) — infuse over minimum 60 min (1g over 60 min, 1.5g over 90 min, 2g over 120 min)
Linezolid Oxazolidinone — MRSA alternative
- Mechanism: inhibits 50S ribosomal subunit — bacteriostatic (bactericidal against streptococci)
- Excellent oral bioavailability (100%) — suitable for step-down from IV
- Advantage over vancomycin: superior lung penetration (VAP), VRE coverage, no nephrotoxicity
- Dose: 600 mg IV/PO q12h
- MAO inhibitor properties — serotonin syndrome risk with SSRIs, SNRIs, tramadol, fentanyl — review concurrent medications
- Bone marrow suppression with prolonged use (>2 weeks) — monitor FBC weekly
- Duration <28 days recommended; dose adjustment not required in renal/hepatic failure
Last-Resort & Resistant Organism Agents
Colistin (Polymyxin E) Last-resort — XDR organisms
- Mechanism: disrupts outer membrane of gram-negative bacteria — polymyxin
- Reserved for: CRE (carbapenem-resistant Enterobacterales), XDR Acinetobacter baumannii, XDR Pseudomonas aeruginosa
- Dose: based on colistin base activity (CBA) — loading dose 9 MU CBA, then 4.5 MU q12h (renal dose adjustment essential)
- Nephrotoxicity: occurs in 30–50% of patients — monitor SCr q24-48h; avoid concurrent nephrotoxins
- Neurotoxicity: perioral paraesthesias, neuromuscular blockade — monitor
- Combination therapy recommended (with meropenem/rifampicin/fosfomycin) — colistin monotherapy inadequate
Aminoglycosides (Gentamicin / Amikacin) Concentration-dependent
- Gram-negative coverage including Pseudomonas; synergistic with beta-lactams for gram-positive endocarditis
- Once-daily extended interval dosing (ODD): gentamicin 5–7 mg/kg q24h; amikacin 15–20 mg/kg q24h
- Monitoring: 8h post-dose level plotted on Hartford nomogram to determine dosing interval (q24h/q36h/q48h)
- Nephrotoxicity and ototoxicity — concentration-trough dependent; ODD reduces risk
- Avoid if CrCl <30 mL/min or impractical to monitor — single-dose use may be justified in severe gram-negative sepsis
Antifungal Agents
Antifungal Therapy in ICU
Fluconazole Triazole — Candida first-line
- Coverage: Candida albicans, C. tropicalis, C. parapsilosis (non-krusei/non-glabrata)
- Dose: 400–800 mg IV/PO loading, then 200–400 mg daily; 800 mg/day for candidaemia
- Not active against C. krusei (intrinsic resistance) or many C. glabrata isolates
- Excellent oral bioavailability — early oral step-down feasible
- Multiple drug interactions via CYP2C9/CYP3A4 inhibition — check interactions (warfarin, phenytoin, tacrolimus)
Caspofungin / Anidulafungin Echinocandins — broad Candida
- Mechanism: inhibit beta-1,3-glucan synthase — disrupts fungal cell wall
- Coverage: all Candida spp. (including fluconazole-resistant), some Aspergillus
- First-line for invasive candidiasis in critically ill patients (2016 IDSA guidelines)
- Caspofungin: 70 mg loading then 50 mg daily IV; no renal dose adjustment
- Anidulafungin: 200 mg loading then 100 mg daily IV — no hepatic dose adjustment
- Minimal drug interactions; well-tolerated
Voriconazole Triazole — invasive aspergillosis
- First-line for invasive pulmonary aspergillosis in ICU
- Dose: 6 mg/kg q12h × 2 doses (loading), then 4 mg/kg q12h IV; oral 200 mg q12h
- TDM required: trough target 1–5.5 mg/L — non-linear pharmacokinetics (CYP2C19 polymorphism causes significant variability)
- Visual disturbances (photopsia), hepatotoxicity, QTc prolongation, photosensitivity
- IV formulation contains sulphobutylether-beta-cyclodextrin vehicle — avoid in renal failure (accumulates) — use oral formulation or liposomal amphotericin B
High-Alert Medications
These medications bear a heightened risk of causing significant patient harm when used in error. Independent double-check is mandatory before administration. Most require dedicated IV lines, continuous monitoring and clearly documented indications and target parameters.
Insulin Infusions
Insulin Infusion Protocol — NICE-SUGAR
NICE-SUGAR Trial (NEJM 2009)
Intensive glycaemic control (target 4.5–6.0 mmol/L) increased 90-day mortality vs conventional control. Hypoglycaemia (<2.2 mmol/L) was significantly more common and independently associated with increased mortality.
- Glycaemic target for critically ill patients: 6–10 mmol/L (108–180 mg/dL)
- Avoid glucose <4.4 mmol/L — associated with increased mortality
- Monitoring frequency: Q1–2h during active titration; Q2–4h once stable in target range
- Insulin infusion: use protocol-driven sliding scale — fixed algorithms reduce hypoglycaemia incidence
- Commence when blood glucose >10 mmol/L on 2 consecutive readings
- Enteral/parenteral nutrition changes require re-titration of insulin infusion rate
- Continuous glucose monitoring (CGM) devices: increasing use in ICU — validate against ABG/point-of-care glucose
- Hypoglycaemia management: 50 mL of 50% dextrose IV, recheck in 15 minutes, adjust insulin infusion
Electrolyte Replacements
Intravenous Potassium
Never give IV potassium as undiluted bolus — Cardiac Arrest Risk
Concentrated potassium chloride (KCl) injection must ALWAYS be diluted before administration. Undiluted KCl directly induces fatal cardiac arrhythmias.
- Peripheral IV: maximum 40 mmol/L concentration; maximum 10 mmol/h via peripheral line
- Central IV: up to 40 mmol/h via central line with continuous ECG monitoring
- Rates >10 mmol/h: mandatory continuous ECG monitoring — risk of VF/VT
- Standard replacement: 40 mmol KCl in 100 mL NaCl 0.9% over 1h via central line with ECG monitoring
- Target serum K+ in ICU: 3.5–5.0 mmol/L (maintain >4.0 mmol/L in arrhythmia-prone patients)
- Recheck serum K+ 1–2h after significant replacement infusion
Magnesium Sulphate
- Eclampsia/pre-eclampsia: loading 4g IV over 15–20 min, then 1–2g/h maintenance infusion; therapeutic level 2–3.5 mmol/L
- Refractory VF/VT (hypomagnesaemia or torsades de pointes): 2g IV over 1–2 min
- Severe acute asthma/bronchospasm: 2g IV over 20 min (single dose)
- Target serum Mg2+: 0.7–1.0 mmol/L; ICU replacement target 1.0–1.5 mmol/L in cardiac patients
- Toxicity signs (Mg2+ >3.5 mmol/L): loss of deep tendon reflexes (first sign), respiratory depression, cardiac arrest
- Antidote for Mg2+ toxicity: calcium gluconate 10 mL of 10% IV (antagonises Mg2+ at NMJ and cardiac membrane)
Anticonvulsants & Antiarrhythmics
IV Phenytoin / Fosphenytoin
Rate Limitation — Cardiac Toxicity Risk
IV phenytoin must be administered at ≤50 mg/min in adults (≤1 mg/kg/min in children). Faster infusion rates cause hypotension, bradycardia, heart block, and cardiac arrest ("purple glove syndrome" with extravasation).
- Always administer in 0.9% NaCl — precipitates immediately in dextrose solutions
- Incompatible with most other IV medications — dedicated IV line required
- ECG monitoring and blood pressure monitoring mandatory during infusion
- Loading dose: 15–20 mg/kg IV at ≤50 mg/min; maintenance 4–6 mg/kg/day
- Therapeutic range: 10–20 mg/L (total); correct for albumin in hypoalbuminaemia
- Fosphenytoin (prodrug): safer infusion rate up to 150 mg PE/min, compatible with dextrose — preferred when available
Amiodarone
- Dose: VF/VT arrest — 300 mg IV bolus (central preferred); SVT/AF — 5 mg/kg over 20–60 min, then 900 mg over 24h
- Central venous access strongly preferred — highly irritant, causes phlebitis and thrombophlebitis peripherally
- QTc prolongation monitoring — avoid with other QT-prolonging drugs (fluoroquinolones, azithromycin, haloperidol)
- Hypothyroidism or hyperthyroidism (37% iodine by weight) — monitor TFTs during prolonged use
- Pulmonary toxicity: acute (within weeks, ARDS-like) or chronic — monitor chest X-ray and DLCO
- Hepatotoxicity: elevated LFTs — monitor during loading and ongoing therapy
- Extremely long half-life (40–55 days) — toxicity may manifest weeks after discontinuation
Heparin & Thrombolysis
Heparin Infusions (UFH)
- Therapeutic anticoagulation target: APTT 1.5–2.5× control (typically 60–100 seconds)
- Loading dose: 80 units/kg IV bolus; initial infusion 18 units/kg/h — adjust per weight-based nomogram
- APTT monitoring: 6h after each rate change, then q24h when stable
- HIT (Heparin-Induced Thrombocytopenia) surveillance: platelet count on Days 5–10 of heparin therapy
- 4T score for HIT probability — if high/intermediate, stop heparin immediately, switch to argatroban or fondaparinux
- HIT is prothrombotic — do not simply discontinue and observe; alternative anticoagulation required
- Antidote: protamine sulphate (1 mg per 100 units heparin given in preceding 2–3h)
Thrombolysis (tPA / Alteplase)
Contraindications Checklist Required
Must complete formal contraindications checklist before administration. Intracranial haemorrhage risk 0.5–3%. Always check BP — hypertension must be treated before and during thrombolysis.
- STEMI: 0.9 mg/kg (max 90 mg) — 10% as bolus over 1 min, remainder over 60 min
- Ischaemic stroke: 0.9 mg/kg (max 90 mg) — same protocol; must be within 4.5h of symptom onset
- Massive PE: 100 mg over 2h (or 0.6 mg/kg over 15 min in cardiac arrest)
- BP targets: maintain BP <185/110 mmHg before/during, <180/105 mmHg for 24h post-infusion
- No anticoagulation for 24h post-alteplase (stroke) — restart heparin 24h post if head CT clear
- Absolute contraindications: active intracranial bleed, recent (<3 months) intracranial surgery/trauma/stroke, intracranial neoplasm, suspected aortic dissection, active significant bleeding
GCC Clinical Context
GCC ICU Pharmacology Practices
- Vancomycin AUC-guided monitoring adopted across major GCC tertiary centres (aligned with ASHP/IDSA/SIDP 2020 guidelines)
- High prevalence of CRE (carbapenem-resistant Enterobacterales) and CRAB (carbapenem-resistant Acinetobacter baumannii) in GCC hospitals — robust antibiotic stewardship programmes mandated by MOH and hospital accreditation bodies
- Colistin use remains prevalent for XDR organisms — combination regimens standard of care
- National antibiotic stewardship programmes in Saudi Arabia (SCFHS/MOH), UAE (DHA/HAAD/DOH), Qatar, Kuwait, Bahrain, Oman aligned with WHO AMR action plans
- Joint Commission International (JCI) and CBAHI accreditation require documented stewardship programmes, medication reconciliation, and high-alert medication protocols
- PICS (Post-Intensive Care Syndrome) awareness increasing — ABCDEF bundle implementation growing across GCC ICUs
DHA / DOH / SCFHS Exam Focus Areas
- Vasopressor mechanisms and appropriate first-line selection (noradrenaline for septic shock)
- RASS scale targets and sedation hold protocols (SAT/SBT)
- Suxamethonium hyperkalaemia contraindications — burns, denervation, immobility
- Propofol infusion syndrome (PRIS) risk factors and monitoring
- Vancomycin therapeutic drug monitoring (AUC vs trough-only)
- NICE-SUGAR glycaemic target (6–10 mmol/L) and hypoglycaemia avoidance
- IV potassium safety: never undiluted, concentration limits, ECG monitoring
- Amiodarone toxicities: thyroid, pulmonary, hepatic, QTc
- Cisatracurium Hofmann elimination — organ-independent clearance
- Dexmedetomidine: cooperative sedation, alpha-2 mechanism, bradycardia/hypotension SE
- Sugammadex 16 mg/kg for immediate reversal of RSI-dose rocuronium
- Adrenaline interference with lactate in septic shock monitoring
MCQ Practice Questions — DHA/DOH/SCFHS Style
Q1.A 58-year-old patient in the ICU has been on a propofol infusion at 6 mg/kg/h for 72 hours. Arterial blood gas shows pH 7.22, lactate 4.8 mmol/L, and creatine kinase is 12,000 U/L. What is the most likely diagnosis?
C — Propofol Infusion Syndrome (PRIS). Key features: high-dose propofol (>5 mg/kg/h) for >48h, metabolic acidosis, elevated CK (rhabdomyolysis), lactic acidosis. Stop propofol immediately and switch to alternative sedation. Monitor for cardiac failure and renal failure.
Q2.A ventilated patient in septic shock requires noradrenaline titration. His weight is 80 kg. The infusion is running at 10 mL/h using a 4 mg/50 mL preparation. What is his current noradrenaline dose in mcg/kg/min?
B — 0.167 mcg/kg/min. Calculation: 4 mg/50 mL = 80 mcg/mL. Rate 10 mL/h = 10/60 mL/min = 0.167 mL/min. Dose = 80 mcg/mL × 0.167 mL/min = 13.33 mcg/min. Per kg = 13.33/80 = 0.167 mcg/kg/min.
Q3.A 45-year-old patient with extensive burns from 4 weeks ago requires emergency intubation. Which neuromuscular blocking agent should be AVOIDED?
B — Suxamethonium. Burns >24–48h cause upregulation of extrajunctional ACh receptors. Suxamethonium causes massive potassium release from these receptors → fatal hyperkalaemia. Use rocuronium 1.2 mg/kg as the RSI agent. The risk persists for weeks to months post-burn.
Q4.According to the NICE-SUGAR trial, what is the recommended blood glucose target range for critically ill ICU patients?
B — 6.0–10.0 mmol/L. The NICE-SUGAR trial (NEJM 2009) demonstrated that tight glycaemic control (4.5–6.0 mmol/L) increased 90-day mortality compared to conventional control (6–10 mmol/L). Hypoglycaemia was significantly more frequent in the tight control group and independently associated with mortality.
Q5.A patient receiving vancomycin for MRSA bacteraemia has a measured AUC of 680 mg·h/L. Based on current ASHP/IDSA/SIDP 2020 guidelines, this is:
C — Supra-therapeutic. AUC/MIC target is 400–600 mg·h/L (assuming MIC = 1 mg/L). AUC of 680 mg·h/L exceeds this range and is associated with increased risk of nephrotoxicity without additional clinical benefit. The dose should be reduced. Trough-only monitoring (target 15–20 mg/L) is no longer recommended as the primary TDM strategy.
Q6.Dexmedetomidine is described as producing "cooperative sedation." Which receptor mechanism explains why patients remain rousable with this agent?
B — Alpha-2 adrenoceptor agonism at the locus coeruleus. This mimics natural sleep pathways (unlike GABA agonists which produce drug-induced sedation). Patients are sedated but can be aroused to follow commands. No respiratory depression — a key advantage in ICU. Main side effects: bradycardia and hypotension.
Q7.Which antimicrobial agent undergoes Hofmann elimination (organ-independent degradation), making it the preferred neuromuscular blocking agent for patients with combined renal and hepatic failure?
C — Cisatracurium. Hofmann elimination is a spontaneous, temperature- and pH-dependent chemical degradation that does not require renal or hepatic function. Cisatracurium is therefore the NMBA of choice for prolonged ICU infusions and for patients with organ failure, as accumulation does not occur regardless of renal or liver impairment.
Q8.A nurse is preparing to administer IV phenytoin 1g for seizure management. Which of the following is correct?
B — 0.9% NaCl at maximum 50 mg/min with continuous ECG monitoring. Phenytoin precipitates in dextrose solutions (never use glucose-containing diluents). Maximum rate is 50 mg/min in adults to prevent hypotension, bradycardia and cardiac arrest. Continuous BP and ECG monitoring are mandatory throughout the infusion.
Q9.The SOAP II trial compared dopamine versus noradrenaline in shock. What was the main finding that changed practice?
B — Dopamine was associated with significantly more arrhythmic events (24.1% vs 12.4%) and higher 28-day mortality in the cardiogenic shock subgroup compared to noradrenaline. This confirmed noradrenaline as the vasopressor of choice, with dopamine not recommended as first-line therapy in septic shock per Surviving Sepsis Campaign guidelines.
Q10.Remifentanil is chosen over fentanyl for a neurological ICU patient requiring daily sedation holds for GCS assessment. What pharmacokinetic property makes remifentanil most suitable for this purpose?
B — Ultra-short context-sensitive half-life (3–5 min). Remifentanil is metabolised by non-specific plasma and tissue esterases — its offset is independent of infusion duration (unlike fentanyl which accumulates in prolonged infusions). This allows neurological assessment within minutes of reducing or stopping the infusion without formal sedation holds, which is a significant advantage in neurocritical care.