Mechanical ventilation tool

ARDS strategy, tidal volume, and PEEP/FiO₂ guidance

ARDSNet Calculator & Assistant

Use this ARDSNet calculator to estimate predicted body weight, generate lung-protective tidal volume targets, and compare a current PEEP/FiO₂ combination against the low-PEEP and high-PEEP ARDSNet tables.

Built for ICU clinicians, respiratory therapists, students, and anyone learning practical ARDS ventilation strategy. Pair it with our IBW calculator, P/F ratio & oxygenation index tool, A–a gradient calculator, ARDSNet protocol guide, permissive hypercapnia guide, permissive hypercapnia ICU guide, and the Desired VE calculator.

Open IBW CalculatorCheck P/F RatioRead ABG Guide
Protocol goal
6 mL/kg PBW
Oxygenation target
PaO₂ 55–80
PEEP/FiO₂ examples
30% / +5 · 40% / +5 · 40% / +8

Initial Vent Settings

ARDSNet predicted body weight uses sex and height, not actual body weight.

How to use this ARDSNet tool

  • Enter sex and height to estimate predicted body weight and lung-protective tidal volume targets.
  • Use the 4–6 mL/kg range to anchor ARDSNet-style low tidal volume ventilation.
  • Enter PaO₂, FiO₂, and PEEP to compare the patient’s current settings with the ARDSNet PEEP/FiO₂ table.
  • Reassess plateau pressure, pH, oxygenation, hemodynamics, and synchrony after any ventilator change.

Related PulmTools resources

Titration Assistant

Goal range: PaO₂ 55–80 mmHg or SpO₂ 88–95%. Need the protocol logic behind it? Review the ARDSNet PEEP/FiO₂ table guide.

ARDSNet Protocol Reference

Inclusion criteria

Acute onset of
1. PaO₂/FiO₂ ≤ 300 (corrected for altitude)
2. Bilateral (patchy, diffuse, or homogeneous) infiltrates consistent with pulmonary edema
3. No clinical evidence of left atrial hypertension

Part I: Ventilator setup and adjustment

1. Calculate predicted body weight (PBW):
 Males = 50 + 2.3 × [height (inches) - 60]
 Females = 45.5 + 2.3 × [height (inches) - 60]
2. Select any ventilator mode
3. Set ventilator settings to achieve initial Vₜ = 8 ml/kg PBW
4. Reduce Vₜ by 1 ml/kg at intervals ≤ 2 hours until Vₜ = 6 ml/kg PBW
5. Set initial rate to approximate baseline minute ventilation (not > 35 bpm)
6. Adjust Vₜ and RR to achieve pH and plateau pressure goals below

Oxygenation goal: PaO₂ 55–80 mmHg or SpO₂ 88–95%

Use a minimum PEEP of 5 cm H₂O. Consider incremental FiO₂/PEEP combos.
Lower PEEP/higher FiO₂ tier:
 FiO₂ 0.3 / 0.4 / 0.4 / 0.5 / 0.5 / 0.6 / 0.7 / 0.7 / 0.8 / 0.9 / 1.0
 PEEP 5 / 5 / 8 / 8 / 10 / 10 / 10 / 12 / 14 / 14 / 18–24

Higher PEEP/lower FiO₂ tier:
 FiO₂ 0.3 / 0.3 / 0.3 / 0.3 / 0.3 / 0.4 / 0.4 / 0.5 / 0.5 / 0.6 / 0.8 / 0.9 / 1.0
 PEEP 5 / 8 / 10 / 12 / 14 / 14 / 16 / 16 / 18 / 20 / 22 / 22 / 24

Plateau pressure goal: ≤ 30 cm H₂O

Check Pplat (0.5s insp. pause) q4h and after any PEEP/Vt change:
• If Pplat > 30: ↓ Vₜ in 1 ml/kg steps (min = 4 ml/kg)
• If Pplat < 25 and Vₜ < 6: ↑ Vₜ in 1 ml/kg steps until Pplat ≥ 25 or Vₜ = 6
• If Pplat < 30 and breath stacking or dyssynchrony: ↑ Vₜ to 7–8 ml/kg if Pplat stays ≤ 30

pH goal: 7.30–7.45

Acidosis management (pH < 7.30):
If pH 7.15–7.30: Increase RR until pH > 7.30 or PaCO₂ < 25 (maximum set RR = 35).
If pH < 7.15: Increase RR to 35. If pH remains < 7.15, VT may be increased in 1 ml/kg steps until pH > 7.15.
May give NaHCO₃.

Alkalosis management (pH > 7.45): Decrease vent rate if possible.

I : E ratio goal

Recommend that duration of inspiration be ≤ duration of expiration.

Part II: Weaning

A. Conduct a spontaneous breathing trial daily when:

  1. FiO₂ ≤ 0.40 and PEEP ≤ 8 OR FiO₂ ≤ 0.50 and PEEP ≤ 5.
  2. PEEP and FiO₂ ≤ values of previous day.
  3. Patient has acceptable spontaneous breathing efforts.
  4. Systolic BP ≥ 90 mmHg without vasopressor support.
  5. No neuromuscular blocking agents or blockade.

B. Spontaneous Breathing Trial (SBT):

If all above criteria are met and subject has been in the study for at least 12 hours, initiate a trial of up to 120 minutes of spontaneous breathing with FiO₂ ≤ 0.5 and PEEP ≤ 5:

  1. Place on T-piece, trach collar, or CPAP ≤ 5 cm H₂O with PS ≤ 5.
  2. Assess for tolerance as below for up to two hours:
    • SpO₂ ≥ 90 and/or PaO₂ ≥ 60 mmHg
    • Spontaneous VT ≥ 4 ml/kg PBW
    • RR ≤ 35/min
    • pH ≥ 7.3
    • No respiratory distress, such as tachycardia, marked accessory muscle use, abdominal paradox, diaphoresis, or marked dyspnea
  3. If tolerated for at least 30 minutes, consider extubation.
  4. If not tolerated, resume pre-weaning settings.

Definition of unassisted breathing

Different from the spontaneous breathing criteria as PS is not allowed

  • Extubated with face mask, nasal prong oxygen, or room air
  • T-tube breathing
  • Tracheostomy mask breathing
  • CPAP ≤ 5 cm H₂O without pressure support or IMV assistance

ARDSNet quick questions

What tidal volume does ARDSNet usually target?

ARDSNet commonly targets about 6 mL/kg predicted body weight, with reduction toward 4 mL/kg when needed to control plateau pressure.

What oxygenation goal does ARDSNet use?

A typical ARDSNet oxygenation target is PaO₂ about 55–80 mmHg or SpO₂ about 88–95%, using paired PEEP and FiO₂ adjustments. For the actual ladder structure, see our ARDSNet PEEP/FiO₂ table explanation.

Why pair this with ABG and oxygenation tools?

ARDS ventilation is easier to manage when you look at acid-base status, oxygenation severity, and gas exchange together. Review the ABG interpretation guide, P/F ratio tool, and A–a gradient calculator.