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Acute Respiratory Distress Syndrome (ARDS)

Last updated 11 May 2026 · Critical care
🎧 ARDS deep-dive podcast — "Diagnosing and Treating Severe ARDS"

📋 Key Information Summary

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  • ARDS definition: Acute onset (≤1 week) bilateral opacities on chest imaging not fully explained by effusions, lobar/lung collapse, or nodules, with respiratory failure not fully explained by cardiac failure or fluid overload, with a PaO2/FiO2 ratio ≤300 mmHg on ≥5 cmH2O PEEP.
  • Berlin severity classification: Mild (200 < PaO2/FiO2 ≤300), Moderate (100 < PaO2/FiO2 ≤200), and Severe (PaO2/FiO2 ≤100) — all measured on ≥5 cmH2O PEEP.
  • Leading causes in Australia: Pneumonia (most common), sepsis (non-pulmonary), aspiration, trauma, massive transfusion, pancreatitis, and near-drowning.
  • Lung-protective ventilation is the cornerstone of management: Tidal volume 6 mL/kg IBW, plateau pressure (Pplat) <30 cmH2O, and driving pressure <15 cmH2O.
  • Prone positioning for ≥16 hours/day is mandatory for all patients with moderate-to-severe ARDS (PaO2/FiO2 ≤150) and strongly recommended for mild ARDS with refractory hypoxaemia.
  • Conservative fluid strategy after initial resuscitation — target even or mildly negative cumulative fluid balance to reduce ventilator days and ICU length of stay.
  • Neuromuscular blockade (cisatracurium) may be considered in the first 48 hours for severe ARDS with refractory hypoxia or dyssynchrony, though routine use for 48-hour infusions is no longer standard after the ROSE trial.
  • ECMO (VV-ECMO) should be considered when conventional therapy fails — refer to a designated ECMO centre (Melbourne, Sydney, Brisbane, Adelaide, Perth). EOLIA criteria: PaO2/FiO2 <50 for >3 hours or <80 for >6 hours despite optimal therapy.
  • Venous thromboembolism prophylaxis is essential — use enoxaparin 40 mg SC daily (renal-adjusted) or unfractionated heparin 5,000 units SC BD unless contraindicated.
  • Aboriginal and Torres Strait Islander peoples experience higher rates of pneumonia, sepsis, and delayed access to critical care — rural and remote communities face significant barriers to ECMO and specialist retrieval services.
  • Early rehabilitation (within 72 hours of ICU stabilisation) reduces post-intensive care syndrome, ICU-acquired weakness, and improves functional recovery at 6 months.
  • Nutrition targets: Commence enteral nutrition within 24–48 hours, target 25–30 kcal/kg/day and 1.2–2.0 g protein/kg/day; avoid parenteral nutrition in the first 7 days unless enteral route is contraindicated.
  • In-hospital mortality remains 35–45% for severe ARDS in Australian ICUs. Early recognition, protocolised lung-protective ventilation, and escalation to specialist centres improve outcomes.
🎬 ARDS clinical explainer — "The ARDS Clinical Pathway"

Introduction & Australian Epidemiology

Acute Respiratory Distress Syndrome (ARDS) is a life-threatening form of respiratory failure characterised by acute, diffuse, inflammatory lung injury leading to increased pulmonary vascular permeability, increased lung weight, and loss of aerated lung tissue. ARDS represents a spectrum of severity and is a common reason for ICU admission in Australian hospitals, accounting for approximately 10–15% of all ICU admissions and up to 23% of mechanically ventilated patients.

The landmark ARDSNet trial (2000) demonstrated a 22% relative reduction in mortality with low tidal volume ventilation (6 mL/kg IBW versus 12 mL/kg IBW), establishing lung-protective ventilation as the standard of care. Despite advances, ARDS remains under-recognised globally — the LUNG SAFE study found that 40% of ARDS cases were not identified by clinicians.

Australian Incidence and Burden

  • The incidence of ARDS in Australian and New Zealand ICUs is estimated at 82–95 cases per 100,000 population per year (ANZICS data).
  • In-hospital mortality: mild ARDS ~27%, moderate ARDS ~32%, severe ARDS ~45%.
  • The COVID-19 pandemic significantly increased ARDS presentations, with Victorian and NSW ICUs managing surge capacity during 2020–2022.
  • Aboriginal and Torres Strait Islander Australians have a 1.5–2× higher incidence of severe pneumonia and sepsis (the leading triggers of ARDS) compared with non-Indigenous Australians.
  • ICU bed availability in rural and remote Australia is limited — retrieval services (e.g., Royal Flying Doctor Service, NSW Air Ambulance, QGAP) are critical for timely escalation.

Common Aetiological Triggers

Pulmonary (Direct) Extrapulmonary (Indirect)
Community-acquired pneumonia (bacterial, viral including SARS-CoV-2, influenza) Non-pulmonary sepsis (e.g., intra-abdominal, urinary)
Aspiration of gastric contents Major trauma / burns
Inhalational injury (smoke, toxic gas) Massive transfusion (≥10 units pRBCs in 24 hours)
Pneumocystis jirovecii pneumonia (immunocompromised) Acute pancreatitis
Pulmonary contusion Drug overdose (opioids, salicylates, tricyclics)
Near-drowning Cardiopulmonary bypass (post-cardiac surgery)
Acute Respiratory Distress Syndrome (ARDS) infographic — Berlin definition, oxygenation severity, lung-protective ventilation, prone positioning, ECMO criteria, and Australian intensive-care context
Tap or click image to enlarge — Acute Respiratory Distress Syndrome: pathophysiology, Berlin definition, severity, ventilator strategy, and rescue therapies.
ARDS infographic, full size

Berlin Definition — Diagnostic Criteria & Severity Classification

The Berlin Definition (2012) replaced the earlier American–European Consensus Conference (AECC) criteria and provides a more reliable framework for ARDS diagnosis and severity stratification. The definition has four required components and three severity categories.

Required Criteria (All Four Must Be Met)

1
Timing
Acute onset within 1 week of a known clinical insult, or new or worsening respiratory symptoms.
2
Chest Imaging
Bilateral opacities on chest X-ray or CT scan not fully explained by effusions, lobar/lung collapse, or nodules. CT typically demonstrates ground-glass opacification with dependent consolidation.
3
Origin of Pulmonary Oedema
Respiratory failure not fully explained by cardiac failure or fluid overload. Requires objective assessment (echocardiography) where no risk factor for ARDS is present. NT-proBNP <300 pg/mL or BNP <100 pg/mL argues against hydrostatic oedema.
4
Oxygenation — PaO2/FiO2 Ratio
Must be measured on ≥5 cmH2O PEEP (via NIV or invasive ventilation). If ABG unavailable, SpO2/FiO2 ratio ≤315 can be used as a surrogate (corresponds to PaO2/FiO2 ≤300).

Berlin Severity Classification

Mild
PaO2/FiO2 201–300 mmHg
Typically manageable with non-invasive ventilation (NIV/CPAP) or low-level invasive PEEP. Mortality approximately 27%. May be managed outside ICU in select patients with close monitoring.
Setting: HDU or ICU with close respiratory monitoring
Moderate
PaO2/FiO2 101–200 mmHg
Requires invasive mechanical ventilation with lung-protective strategy. Consider prone positioning early. Mortality approximately 32%. Higher likelihood of multi-organ dysfunction.
Setting: ICU with mechanical ventilation
Severe
PaO2/FiO2 ≤100 mmHg
Refractory hypoxaemia despite optimal ventilation. High mortality (~45%). Consider early referral for ECMO. Prone positioning mandatory. Neuromuscular blockade may be required. Most benefit from centralised care at tertiary centres.
Setting: Tertiary ICU with ECMO capability
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Key exclusion: ARDS cannot be diagnosed if respiratory failure is fully explained by cardiac failure or fluid overload alone. Always perform focused echocardiography (FATE/FOCUS) to assess LV function and exclude cardiogenic pulmonary oedema when clinical context is unclear.

Risk Factors for ARDS

Direct Lung Injury Indirect Lung Injury Patient-Related Risk Factors
Pneumonia (most common) Sepsis (non-pulmonary) Chronic alcohol abuse (3× increased risk)
Aspiration Polytrauma / burns Smoking (current)
Inhalation injury Massive transfusion Obesity (BMI >30)
Pulmonary contusion Pancreatitis Diabetes mellitus (type 2)
Near-drowning Cardiopulmonary bypass Immunosuppression

Mechanical Ventilation — Lung-Protective Strategy

Lung-protective ventilation is the single most important intervention that improves survival in ARDS. The strategy centres on low tidal volumes, limited plateau pressures, and appropriate PEEP to prevent both ventilator-induced lung injury (VILI) from volutrauma/barotrauma and atelectrauma from cyclic alveolar collapse.

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Standard lung-protective ventilation: Tidal volume 6 mL/kg IBW, plateau pressure <30 cmH2O, driving pressure <15 cmH2O, respiratory rate adjusted to maintain pH >7.20 (up to 35 breaths/min). These parameters are supported by the ARDSNet and ART trials and form the basis of ANZICS and CICM recommendations.

Ideal Body Weight (IBW) Calculation

Tidal volume is set according to ideal body weight (IBW), not actual body weight, to avoid volutrauma in obese patients and underventilation in underweight patients.

Parameter Formula (Males) Formula (Females)
IBW (kg) 50 + 0.91 × (height in cm − 152.4) 45.5 + 0.91 × (height in cm − 152.4)

Ventilator Settings — Step-by-Step Protocol

1
Mode
Volume-controlled ventilation (VC-AC) or pressure-controlled ventilation (PC-AC). Both are acceptable if tidal volume and plateau pressure targets are met. Set tidal volume to 6 mL/kg IBW (range 4–8 mL/kg IBW).
2
Plateau Pressure Limit
Measure Pplat with an inspiratory hold of 0.5 seconds. Target <30 cmH2O. If Pplat ≥30: reduce tidal volume in decrements of 1 mL/kg (minimum 4 mL/kg), increase I:E ratio, or consider neuromuscular blockade.
3
Driving Pressure (ΔP)
ΔP = Pplat − PEEP. Target <15 cmH2O. Driving pressure is an independent predictor of mortality (Amato et al., 2015). If ΔP ≥15, reduce VT or adjust PEEP.
4
Respiratory Rate
Set RR to achieve minute ventilation targets while maintaining pH >7.20. Acceptable range 20–35 breaths/min. Allow permissive hypercapnia (PaCO2 up to 60–70 mmHg) if pH >7.20. Avoid RR >35 due to auto-PEEP risk.
5
FiO2 and PEEP
Target SpO2 88–95% (acceptable range). Use the lowest FiO2 to achieve target. Titrate PEEP per ARDSNet PEEP/FiO2 table. Maintain PEEP ≥5 cmH2O to prevent derecruitment. High PEEP strategies (e.g., PEEP 12–15) may benefit moderate-severe ARDS.

ARDSNet PEEP / FiO2 Titration Table

FiO2 0.3 0.4 0.4 0.5 0.5 0.6 0.7 0.7 0.8 0.9 1.0
PEEP (cmH2O) 5 5 8 8 10 10 10 12 14 14 14–18
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Permissive hypercapnia: Elevated PaCO2 (up to 60–70 mmHg) is acceptable when using low tidal volumes, provided pH remains >7.20. Sodium bicarbonate infusion may be considered if pH <7.15 despite maximising ventilation. Avoid in patients with respiratory acidosis-driven lactic acidosis — these require increased minute ventilation or ECMO.

Non-Invasive Ventilation (NIV) in ARDS

  • NIV (BiPAP/CPAP) may be trialled in mild ARDS only (PaO2/FiO2 200–300) in patients without haemodynamic instability, multi-organ failure, or altered consciousness.
  • HFNO (high-flow nasal oxygen) at up to 60 L/min may be used in mild ARDS, particularly in immunocompromised patients where intubation risk is high (FLORALI trial).
  • Failure criteria: If PaO2/FiO2 <150 after 1–2 hours of NIV/HFNO, or RR >30, or haemodynamic instability, proceed to invasive ventilation. Delayed intubation increases mortality.

Rescue Oxygenation — Apnoeic Oxygenation

  • During intubation of ARDS patients, use apnoeic oxygenation (15 L/min via nasal prongs + 15 L/min via ETT in pharynx) to extend safe apnoea time.
  • Pre-oxygenate with 100% FiO2 for ≥3 minutes in a semi-recumbent position, or use NIV/CPAP for pre-oxygenation.
  • Have a failed intubation plan — video laryngoscope as first-line device in ICU intubations (difficult airway more likely in critically ill, obese, or oedematous patients).

Advanced Therapies — Prone Positioning, Neuromuscular Blockade, Recruitment, ECMO

Prone Positioning

Prone positioning is one of the most effective interventions for moderate-to-severe ARDS. The PROSEVA trial (2013) demonstrated an absolute mortality reduction of 16.8% (28-day mortality 16% vs 32.8%) in patients with PaO2/FiO2 <150 when prone sessions lasted ≥16 hours per day.

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Mandatory in moderate-to-severe ARDS: All patients with PaO2/FiO2 <150 on FiO2 ≥0.6 and PEEP ≥5 cmH2O should receive prone positioning for ≥16 hours/day. Continue until PaO2/FiO2 >150 consistently in the supine position for ≥4 hours after a prone session.
  • Technique: Minimum 3–5 staff required. Use a prone positioning bed or mattress overlay. Secure ETT, central lines, chest drains, and urinary catheter. Pad pressure points (face, shoulders, pelvis, knees). Reposition arms every 2 hours.
  • Duration: ≥16 hours per session (20 hours preferred). Typically 1–2 sessions may be required; some patients need prolonged prone ventilation over days.
  • Monitoring: Continuous SpO2, ETCO2, arterial line BP. Check ETT position after each turn. Monitor for ETT displacement, loss of IV access, brachial plexus injury, and pressure injuries.
  • Contraindications: Unstable spinal fracture, open abdomen, haemodynamic instability requiring escalating vasopressors (relative), severe facial/neck burns, recent sternotomy (relative — discuss with cardiac surgery).

Neuromuscular Blocking Agents (NMBAs)

The role of NMBAs in ARDS has evolved. The ACURASYS trial (2010) showed benefit with 48-hour cisatracurium infusion in severe ARDS, but the larger ROSE trial (2019) found no difference in 90-day mortality with routine NMBA use. Current practice favours early, short-term use for specific indications rather than a blanket 48-hour protocol.

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Cisatracurium
Nimbex® · Neuromuscular blocking agent (benzylisoquinolinium)
Adult dose Loading: 0.15 mg/kg IV bolus; Maintenance: 1–3 μg/kg/min continuous infusion
Indications in ARDS Refractory hypoxaemia, ventilator dyssynchrony despite deep sedation (RASS −4 to −5), high transpulmonary pressures
Duration Short-term (24–48 hours); reassess daily. Do not use routinely for all ARDS patients.
Renal adjustment Hofmann elimination — no renal dose adjustment required
Key monitoring Train-of-four (TOF) monitoring; must have deep sedation (RASS −5) before commencing. Monitor for ICU-acquired weakness (prolonged use >48 hours).
PBS status ✔ PBS General Benefit (injectable)
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Never paralyse without deep sedation: Cisatracurium must only be administered when the patient is deeply sedated (RASS −5). Paralysis without adequate sedation causes extreme distress, tachycardia, and is ethically unacceptable. Document concurrent sedation level every 4 hours.

Recruitment Manoeuvres

Recruitment manoeuvres (RMs) aim to reopen collapsed alveoli. The ART trial (2017) showed that a staircase recruitment manoeuvre with PEEP titration did not reduce mortality and may have caused harm (barotrauma, haemodynamic compromise). Current recommendations are cautious.

  • Sustained inflation: CPAP 35–40 cmH2O for 30–40 seconds. Simple but may cause haemodynamic compromise and barotrauma. Not routinely recommended.
  • Staircase / incremental PEEP recruitment: Increase PEEP in steps of 5 cmH2O (with constant driving pressure) while monitoring compliance. Not recommended as a routine strategy (ART trial).
  • Practical approach: A single brief sustained inflation (30 cmH2O for 30 seconds) may be used transiently after disconnect events (suctioning, prone turn) to restore oxygenation. Titrate PEEP using a decremental PEEP trial after recruitment if attempted.
  • Contraindications: Barotrauma (pneumothorax), haemodynamic instability, bullous lung disease, raised intracranial pressure.

Extracorporeal Membrane Oxygenation (ECMO)

Venovenous ECMO (VV-ECMO) provides gas exchange when the lungs are unable to maintain adequate oxygenation and/or ventilation despite maximal conventional therapy. The EOLIA trial (2018) showed a trend towards improved survival with early ECMO in severe ARDS, though the crossover rate complicates interpretation. Meta-analyses suggest a significant mortality benefit.

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ECMO referral criteria (EOLIA / CESAR-based): Refer early to a designated ECMO centre when:
• PaO2/FiO2 <50 mmHg for >3 hours OR PaO2/FiO2 <80 mmHg for >6 hours despite optimal therapy (including prone positioning)
• Uncompensated hypercapnia with pH <7.20 despite maximising ventilation
• Excessive plateau pressures (>30 cmH2O despite VT 4 mL/kg IBW)
• Murray Lung Injury Score ≥2.5–3.0
• Reversible underlying cause (avoid ECMO in irreversible multi-organ failure)

Australian ECMO Centres

  • Victoria: The Alfred Hospital, Royal Melbourne Hospital
  • New South Wales: Royal Prince Alfred Hospital, St Vincent's Hospital, Westmead Hospital
  • Queensland: Prince Charles Hospital, Royal Brisbane and Women's Hospital
  • South Australia: Royal Adelaide Hospital
  • Western Australia: Royal Perth Hospital, Fiona Stanley Hospital
  • Tasmania, NT, ACT: Retrieval and transfer to mainland ECMO centres via RFDS, NETS, or state retrieval services.

Adjunctive Pharmacotherapies

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Corticosteroids (Dexamethasone / Methylprednisolone)
Dexmethasone® / Solumedrol® · Anti-inflammatory
Evidence Dexamethasone 6 mg daily (as per RECOVERY trial for COVID-19 ARDS) reduced mortality. Methylprednisolone 1 mg/kg/day for 14 days with taper may reduce duration of ventilation in non-COVID ARDS (Meduri et al.; Dexa-ARDS trial 2020 showed benefit with dexamethasone in non-COVID ARDS).
Adult dose Dexamethasone 6 mg IV/PO daily for up to 10 days (COVID-19); Methylprednisolone 1 mg/kg/day IV (non-COVID) for 14 days then taper over 7–14 days
PBS status ✔ PBS General Benefit
Caution Monitor blood glucose closely (steroid-induced hyperglycaemia is common). Check for active infection/tuberculosis. Avoid in immunocompromised without infectious disease input.
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Inhaled Pulmonary Vasodilators
iNO (INOmax®) / Inhaled Epoprostenol (Flolan®) · Rescue therapy
iNO dose 10–20 ppm via dedicated delivery circuit. Titrate by 5 ppm increments to a maximum of 40 ppm based on SpO2/PaO2 response.
Inhaled epoprostenol 10–50 ng/kg/min via vibrating mesh nebuliser. Increasingly used as a cheaper alternative to iNO in Australian ICUs.
Evidence Reduces PVR and improves V/Q matching in refractory hypoxaemia. Rescue therapy only — no mortality benefit. Use as a bridge to ECMO or to improve oxygenation during prone positioning or transport.
PBS status ✘ Not PBS-listed (hospital funded)

Supportive Care — Fluid Management, Nutrition, Sedation, Complications, Rehabilitation

Fluid Management

The FACTT trial demonstrated that a conservative fluid strategy (targeting even or mildly negative cumulative fluid balance after initial resuscitation) reduced ventilator days and ICU length of stay without increasing non-pulmonary organ failure. Liberal fluid administration worsens pulmonary oedema and prolongs mechanical ventilation.

1
Resuscitation Phase (0–6 hours)
If sepsis-related ARDS: follow ANZICS/SSCG guidelines. 25–30 mL/kg crystalloid bolus (Hartmann's or Plasmalyte-148). Reassess after each bolus — target MAP ≥65 mmHg, urine output ≥0.5 mL/kg/hr, lactate clearance.
2
Stabilisation Phase (6–48 hours)
Switch to restrictive strategy. Maintenance fluids at 1 mL/kg/hr (up to 80 mL/hr). Use vasopressors (noradrenaline first-line) to maintain MAP rather than additional fluid boluses.
3
De-escalation Phase (>48 hours)
Target even or mildly negative cumulative fluid balance. Consider frusemide infusion (0.5–1 mg/kg/hr) or intermittent boluses for fluid removal. Monitor CVP trend, lactate, renal function.
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Fluid choice: Balanced crystalloids (Hartmann's solution, Plasmalyte-148) are preferred over 0.9% sodium chloride (normal saline) in ARDS, as large-volume NS causes hyperchloraemic acidosis and may worsen renal outcomes (SMART trial, SALT-ED trial). Avoid hydroxyethyl starch (HES) — the VISEP and 6S trials showed increased renal failure and mortality in sepsis.

Nutrition

Early enteral nutrition (EN) within 24–48 hours of ICU admission reduces infectious complications, maintains gut mucosal integrity, and may reduce duration of mechanical ventilation. Parenteral nutrition (PN) should be avoided in the first 7 days unless the enteral route is contraindicated (ESPEN/ANZICS guidelines).

Parameter Recommendation
Timing Commence EN within 24–48 hours (if haemodynamically stable on low-dose vasopressors, EN can proceed)
Route Nasoenteric (post-pyloric/nasojejunal preferred if gastric residual >250 mL repeatedly). Nasogastric acceptable as first-line.
Caloric target Indirect calorimetry where available. Otherwise: 25–30 kcal/kg/day (use IBW). In acute phase (first 7 days), consider permissive underfeeding (up to 70% of target).
Protein target 1.2–2.0 g protein/kg/day (IBW). Higher protein intake (≥1.5 g/kg) is associated with reduced mortality in ARDS.
Monitoring Gastric residual volumes (GRV) every 4–6 hours; hold EN if GRV >500 mL. Monitor phosphate, magnesium, potassium (refeeding risk).
Omega-3 fatty acids Not routinely recommended. The OMEGA trial and subsequent meta-analyses showed no benefit from EPA/DHA supplementation in ARDS.

Sedation and Analgesia

ARDS patients require deeper sedation than general ICU patients, particularly during prone positioning and when using NMBAs. However, daily sedation interruption and minimising sedation depth when safe reduces ventilator days, delirium, and ICU length of stay (eCASH concept: early Comfort using Analgesia, minimal Sedation, and maximal Humane care).

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Fentanyl
Sublimaze® · Opioid analgesic
Adult dose 25–100 μg IV bolus PRN; Infusion: 25–200 μg/hr titrated to BPS/CPOT target
Rationale First-line analgesic in ARDS. Short-acting, haemodynamically stable. No histamine release. Preferred over morphine in renal impairment.
PBS status ✔ PBS General Benefit (injectable)
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Propofol
Diprivan® · Sedative-hypnotic
Adult dose 5–50 μg/kg/min IV infusion. Titrate to RASS target (typically −2 to −4 in ARDS; −5 if NMBAs in use).
Caution Propofol infusion syndrome (PRIS) risk at doses >80 μg/kg/min for >48 hours. Monitor CK, lactate, triglycerides. Dose limit <4 mg/kg/hr (<67 μg/kg/min).
PBS status ✔ PBS General Benefit (injectable)
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Dexmedetomidine
Precedex® · α2-agonist sedative
Adult dose Loading: 1 μg/kg IV over 10 min; Maintenance: 0.2–0.7 μg/kg/hr
Rationale Reduces delirium incidence. Facilitates lighter sedation with preserved respiratory drive. Useful for sedation weaning and during daily sedation interruption trials.
Caution Bradycardia and hypotension. Avoid in severe haemodynamic instability.
PBS status ⚠ PBS Authority Required (ICU use)

Delirium Prevention and Management

  • Assess using CAM-ICU (Confusion Assessment Method for ICU) twice daily.
  • Non-pharmacological strategies: lightening sedation daily, early mobilisation, sleep hygiene (reducing noise and light at night), reorientation, family presence, hearing aids and glasses where applicable.
  • Avoid antipsychotics routinely. Haloperidol 2.5–5 mg IV/IM may be used for acute agitation with safety risk. Quetiapine 12.5–25 mg PO/NG BD may be considered for hypoactive delirium (limited evidence).
  • Avoid benzodiazepines as primary sedative — associated with increased delirium, longer ventilation, and worse outcomes (MIDEX/PRODEX trials).

Venous Thromboembolism (VTE) Prophylaxis

⚠️
VTE prophylaxis is mandatory in all ARDS patients unless active bleeding or severe coagulopathy. ARDS patients are at extremely high risk of DVT/PE due to immobility, inflammation, and endothelial injury.
  • First-line: Enoxaparin 40 mg SC once daily (adjust for weight: 0.5 mg/kg if >100 kg; 30 mg daily if <50 kg or eGFR <30 mL/min/1.73 m²).
  • Renal impairment (eGFR <30): Unfractionated heparin (UFH) 5,000 units SC BD, or enoxaparin 30 mg SC daily with anti-Xa level monitoring (target 0.2–0.5 IU/mL).
  • Mechanical prophylaxis: Intermittent pneumatic compression (IPC) devices on lower limbs. Use in combination with pharmacological prophylaxis or as sole method if anticoagulation contraindicated.

Prevention of Stress Ulceration

  • Stress ulcer prophylaxis with a proton pump inhibitor (PPI) is recommended for mechanically ventilated patients >48 hours with additional risk factors (coagulopathy, shock, corticosteroids).
  • Pantoprazole 40 mg IV/PO daily (PBS General Benefit). Omeprazole 20 mg PO/NG is an alternative.
  • The PEPTIC trial (2020) showed no significant difference in 90-day mortality between PPI and H2RA; PPI remains preferred due to superior acid suppression.

Ventilator-Associated Pneumonia (VAP) Prevention

  • Elevate head of bed to 30–45° (except during prone positioning).
  • Daily oral care with chlorhexidine 0.12% solution (evidence is mixed; many Australian ICUs use it per NSQHS Standards).
  • Subglottic suctioning ETT where available.
  • Daily sedation interruption and spontaneous breathing trials to assess readiness for extubation.
  • Closed suction systems, heat-movent exchangers (HME) with filter, and minimising circuit disconnections.

Early Rehabilitation in ARDS

ICU-acquired weakness (ICU-AW) affects up to 40–50% of ARDS patients and is the strongest predictor of poor functional outcome at 6–12 months. Early rehabilitation, commencing within 72 hours of ICU stabilisation, is a key component of the recovery bundle.

Day 1–3
Passive range-of-motion exercises (PROM) in all limbs. Positioning changes. Occupational therapy assessment. Assess sedation level for wakefulness windows.
Day 3–7
Active-assisted exercises. Sitting in bed (edge-of-bed sitting). Cycle ergometry (passive/active) where available. Speech pathology review for swallowing and communication.
Day 7–14
Standing (with physiotherapy support). Transfer to chair. Active resistance exercises. In-bed cycling. Consider mobilising with ventilator support (if stable on moderate settings).
Post-ICU
Progressive ambulation. Ward-based rehabilitation. Referral to post-ICU follow-up clinic. Psychosocial support for post-intensive care syndrome (PICS). 6-minute walk test at 6 weeks.
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Post-ICU follow-up: Refer all ARDS survivors to a multidisciplinary ICU follow-up clinic (available at major tertiary hospitals in Sydney, Melbourne, Brisbane). Screen for PTSD, depression, anxiety (using PCL-5, PHQ-9, GAD-7), cognitive impairment, and persistent physical disability. Up to 50% of ARDS survivors experience significant psychological morbidity at 12 months.

Aboriginal and Torres Strait Islander Health Considerations

Aboriginal and Torres Strait Islander Health
Higher burden of disease
Aboriginal and Torres Strait Islander Australians experience 1.5–2 times higher rates of pneumonia, sepsis, and chronic lung disease (including bronchiectasis and post-tuberculosis lung disease) — the leading triggers of ARDS. The AIHW reports significantly higher ICU admission rates for respiratory failure in Indigenous Australians, particularly in the Northern Territory and Far North Queensland.
Remote and rural access
Many Aboriginal and Torres Strait Islander communities are located in remote and very remote areas with limited access to ICUs and mechanical ventilation. Retrieval times of 6–24 hours (via RFDS or NT/QLD retrieval services) may delay definitive care. Early stabilisation and referral from remote health clinics (using CARPA Standard Treatment Manual protocols) is critical.
ECMO access
There are no ECMO-capable facilities in the Northern Territory, and limited access in remote Queensland and Western Australia. Patients requiring ECMO from these regions need inter-hospital transfer to Darwin (Royal Darwin Hospital for stabilisation) then to southern ECMO centres. The retrieval logistics (fixed-wing aircraft, specialist ECMO transport teams) add significant time — early recognition and referral is essential.
Chronic disease comorbidities
Higher prevalence of chronic kidney disease (CKD stages 3–5), type 2 diabetes, rheumatic heart disease, and chronic lung disease in Indigenous Australians increases ARDS mortality risk. Renal impairment affects drug dosing (enoxaparin, cisatracurium — though cisatracurium does not require renal adjustment). Cardiac comorbidities (RHD) complicate fluid management and echocardiographic interpretation.
Communication and cultural safety
Language barriers are common — many patients speak English as a second, third, or fourth language. Interpreter services (e.g., Aboriginal Interpreter Service in NT, available 24/7) must be used for informed consent, family meetings, and end-of-life discussions. Involving family and community in care decisions aligns with culturally safe practice. The concept of "Sorry Business" (bereavement and mourning) may affect family availability and decision-making timelines.
End-of-life care considerations
Community and family input is central to goals-of-care discussions. Advance care planning may be limited; engage Aboriginal Health Workers and Liaison Officers (AHWLOs) early. Where possible, facilitate family presence at the bedside, including from remote communities (via patient-assisted travel schemes). Culturally appropriate end-of-life care should be discussed sensitively and proactively.
Post-ICU rehabilitation
Access to post-ICU rehabilitation, outpatient physiotherapy, and psychological support services is significantly reduced in remote communities. Telehealth rehabilitation programs (where available) and community-based health worker–led recovery programs can partially address this gap. Referral to Aboriginal Community Controlled Health Organisations (ACCHOs) for ongoing follow-up is recommended.

📚 References

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  2. 2. The Acute Respiratory Distress Syndrome Network. Ventilation with lower tidal volumes as compared with traditional tidal volumes for acute lung injury and the acute respiratory distress syndrome. N Engl J Med. 2000;342(18):1301-1308.
  3. 3. Guérin C, Reignier J, Richard JC, et al. Prone positioning in severe acute respiratory distress syndrome. N Engl J Med. 2013;368(23):2159-2168.
  4. 4. Papazian L, Forel JM, Gacouin A, et al. Neuromuscular blockers in early acute respiratory distress syndrome. N Engl J Med. 2010;363(12):1107-1116.
  5. 5. National Heart, Lung, and Blood Institute PETAL Clinical Trials Network; Moss M, Huang DT, Brower RG, et al. Early neuromuscular blockade in the acute respiratory distress syndrome. N Engl J Med. 2019;380(21):1997-2008.
  6. 6. Combes A, Hajage D, Capellier G, et al. Extracorporeal membrane oxygenation for severe acute respiratory distress syndrome (EOLIA). N Engl J Med. 2018;378(21):1965-1975.
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