Ventilator Weaning Calculator

Weaning readiness criteria assessment (RSBI, NIF, etc.).

Respiratory Rate (breaths/min)

Tidal Volume (mL)

NIF / MIP (cmH2O)

PaO2 (mmHg)

FiO2 (fraction)

PEEP (cmH2O)

Tab to move between fields

RSBI (breaths/min/L)

Minute Ventilation (L/min)8.1

P/F Ratio225

Readiness Score (%)100%

Criteria Met (of 5)5

Prediction (0=Not Ready, 1=Marginal, 2=Ready)2

How to Use This Calculator

Enter respiratory rate (breaths/min) and tidal volume (mL) from the ventilator display.
Enter NIF/MIP (cmH2O), PaO2 (mmHg), and FiO2 (fraction) from current ventilator settings and ABG.
Review the rapid shallow breathing index (RSBI = RR/VT) -- RSBI <105 supports weaning readiness.
Check P/F ratio (PaO2/FiO2) -- above 200 generally supports weaning consideration.
Review the composite readiness score and notes on factors that should be optimized before extubation.

How the result changes with Respiratory Rate (breaths/min)

Respiratory Rate (breaths/min)	RSBI (breaths/min/L)
9.6	21
24	53
40	89
54	120

Respiratory Rate (breaths/min): Spontaneous respiratory rate during breathing trial.
Tidal Volume (mL): Spontaneous tidal volume in milliliters.
NIF / MIP (cmH2O): Negative inspiratory force / maximal inspiratory pressure. More negative = stronger (≤ -20 is adequate).
PaO2 (mmHg): Arterial partial pressure of oxygen from ABG.
FiO2 (fraction): Fraction of inspired oxygen (0.21 = room air, 1.0 = 100%).
PEEP (cmH2O): Positive end-expiratory pressure setting.

RSBI (breaths/min/L): Rapid Shallow Breathing Index. < 105 predicts successful weaning (Yang & Tobin).
Minute Ventilation (L/min): RR × Vt. Ideally < 10 L/min for weaning.
P/F Ratio: PaO2/FiO2 ratio. ≥ 150–200 supports weaning readiness.
Readiness Score (%): Composite score (0-100%) based on how many weaning criteria are met.
Criteria Met (of 5): Number of weaning criteria satisfied out of 5.
Prediction (0=Not Ready, 1=Marginal, 2=Ready): Weaning prediction: 0 = not ready, 1 = marginal (consider SBT), 2 = likely ready.

Identify Input Parameters
4 parameters
Respiratory Rate (breaths/min) = 18, Tidal Volume (mL) = 450, NIF / MIP (cmH2O) = -25, PaO2 (mmHg) = 90 = 6 input(s) provided
Calculate RSBI
40 = 40
Calculate Minute Ventilation
Minute Ventilation = rr * vtLiters
8.1 = 8.1
Calculate P/F Ratio
P/F Ratio = pao2 / fio2
225 = 225