| Non-invasive respiratory support |
| Non-invasive ventilation |
| Commence early in patients with mild–moderate ARDS If available, helmet over face mask NIV may be better tolerated Uptitrate PEEP, aiming to optimise the work of breathing Titrate pressure support to target Vt 6–8 ml/kg PBW Monitor closely for changes in tidal volume, minute ventilation, acid–base, work of breathing, hypoxaemia, and haemodynamics Assess success or failure of strategy within 1–2 h of commencement Do not delay intubation when indicated, otherwise continue to review frequently |
| High-flow oxygen |
| Commence early in patients with mild ARDS Consider high-flow oxygen preferentially over NIV in patients with high sputum load Target flows 40–60 L/min, as tolerated |
| Invasive mechanical ventilation |
| Tidal volume |
| Target Vt 6 (4–8) ml/kg PBW If P ≥ 16 cmH2O (after PEEP optimisation), consider targeting lower (4–6 ml/kg PBW) range if RR and acid–base allow If known or high risk for RV dysfunction (see below) and acid–base allows (minimise hypercapnoea), target 4–6 ml/kg PBW to reduce mean airway pressure |
| Plateau pressure |
| During passive ventilation, target Pplat < 30 cmH2O If high pleural pressures present (e.g. abdominal distension, central obesity), higher Pplat may be appropriate (e.g. 30–35 cmH2O); consider use of oesophageal manometry if available If known or high risk for RV dysfunction, following PEEP optimisation, target Pplat < 26–28 cmH2O, or as low as safely able |
| Positive end-expiratory pressure |
| PEEP–FiO2 table reasonable starting point immediately following intubation, prior to assessment of respiratory mechanics, recruitability, and personalised PEEP titration Lower range of PEEP–FiO2 table if non-recruitable and concerns for RV or ICP, higher range if anticipating high pleural pressures (e.g. abdominal distension, central obesity) Assess recruitability and benefit of higher PEEP in moderate–severe ARDS Avoid high-PEEP strategy in patients with mild and/or focal ARDS Create and follow local guidelines on PEEP assessment based on local tools and expertise Reassess optimal PEEP regularly, to include change in clinical status and/or following new intervention that may alter respiratory mechanics (e.g. prone position, NMBA) |
| Controlled mode |
| Volume or pressure targeted mode as per familiarity of the clinician and unit Consider hybrid mode (e.g. assist control) upfront to aid patient–ventilator synchrony Set appropriate pressure and volume alarms as per targets determined above |
| Oxygen targets |
| Target SpO2 90–95% and/or PaO2 60–80 mmHg Higher end of target range desirable in patients with acute RV dysfunction |
| Permissive hypercapnoea |
| Maintain pH > 7.25 In patients with or at risk of RV dysfunction, tolerance of a permissive hypercapnoea requires serial assessment of haemodynamics and RV function |
| Non-ventilatory management |
| Prone positioning |
| Early (< 36 h from invasive mechanical ventilation and ARDS diagnosis) in patients with PaO2/FiO2 < 150 mmHg on optimised PEEP and FiO2 ≥ 0.6 Daily sessions ≥ 12 h per day, continuing until PaO2/FiO2 ≥ 150 mmHg, PEEP ≤ 10 cmH2O and FiO2 ≤ 0.6 for ≥ 4 h after supination Lack of observable benefit (oxygenation or other) is not an indication to discontinue prone positioning. Discontinue only if safety concerns develop (significant haemodynamic instability, worsening respiratory mechanics, etc.) Neuromuscular blockade is not required by default, but may be appropriate in some cases |
| Neuromuscular blockade |
| Consider in early (< 48 h) severe (PaO2/FiO2 ≤100 mmHg) ARDS with hypoxaemia Use in moderate–severe ARDS (PaO2/FiO2 ≤150 mmHg) with an indication for deep sedation (patient–ventilator dyssynchrony and/or high respiratory drive and effort) Use if impaired respiratory mechanics, after a trial bolus favouring potential benefit Review cessation at 48 h |
| Steroids |
| Use if indicated by other pathology with proven or likely benefitInsufficient evidence to support routine use in ARDS |
| Fluid management |
| In patients without shock, a conservative fluid strategy (targeting neutral cumulative fluid balance) initiated early is preferred over diuresis later |
| Cardiorespiratory monitoring |
| Ventilation: non-invasive |
| Clinical assessment of work of breathing and dyspnoea score RR, Vt, minute ventilation, consciousness, heart rate, andblood pressure Oxygenation and acid–base assessment (continuous SpO2 monitoring and intermittent blood gas analysis) Assess circuit leaks, patient tolerance, and pressure areas |
| Ventilation: invasive |
| Passive: PEEPt, Pplat, P (computed from Pplat–PEEPt), Vt (adjusted to PBW), RR Spontaneous efforts; Vt, RR, magnitude of efforts (local institution dependent), patient–ventilator synchrony by ventilator waveform analysis and/or invasive monitoring (e.g. oesophageal manometry) All: continuous pulse oximetry and end-tidal CO2 monitoring where available, correlate with intermittent blood gas analysis as indicated |
| Right ventricle |
| Echocardiographic assessment indicated if (i) pneumonia, (ii) P ≥ 18 cmH2O, (iii) PaO2/FiO2 < 150 mmHg, (iv) PaCO2 ≥ 48 mmHg, (v) shock, and (vi) known or likely pre-existing RV disease Serial echocardiography and/or PAC-based haemodynamic monitoring to guide interventions during IMV if (i) baseline echo is concerning for RV dysfunction, (ii) plan for permissive hypercapnoea, (iii) moderate–severe shock, or (iv) cardiorespiratory deterioration Monitor for shock, renal failure, congestive hepatopathy, and positive fluid balance |
