static_lung_compliance: Static Lung Compliance (Cstat) Calculator

In cliot: Clinical Indices and Outcomes Tools

Static Lung Compliance (Cstat) Calculator

Description

Calculates the Static Lung Compliance (Cstat) of a mechanically ventilated patient. Static compliance represents the distensibility of the lungs and chest wall when there is no airflow (static conditions). It is calculated using the tidal volume, plateau pressure, and positive end-expiratory pressure (PEEP).

Usage

static_lung_compliance(tidal_volume, plateau_pressure, peep)

Arguments

tidal_volume	Numeric. The exhaled tidal volume in milliliters (mL).
plateau_pressure	Numeric. The plateau pressure (Pplat) measured during an inspiratory pause in cmH2O.
peep	Numeric. The Positive End-Expiratory Pressure (PEEP) in cmH2O.

Details

The formula used is:

C_{stat} = \frac{V_T}{P_{plat} - PEEP}

Where:

• C_{stat} is Static Compliance (mL/cmH2O)

• V_T is Tidal Volume (mL)

• P_{plat} is Plateau Pressure (cmH2O)

• PEEP is Positive End-Expiratory Pressure (cmH2O)

Normal static compliance in intubated patients is typically 50-80 mL/cmH2O. Values < 30 mL/cmH2O are often seen in severe ARDS.

Value

A list containing:

Static_Compliance_mL_cmH2O	The calculated static lung compliance.
Interpretation	Clinical interpretation of the compliance value.

References

Suter PM, Fairley B, Isenberg MD. Optimum end-expiratory airway pressure in patients with acute pulmonary failure. N Engl J Med. 1975;292(6):284-289. doi:10.1056/NEJM197502062920604

Examples

# Example 1: Normal Compliance
# Vt 500 mL, Pplat 15 cmH2O, PEEP 5 cmH2O
# Cstat = 500 / (15 - 5) = 50 mL/cmH2O
static_lung_compliance(500, 15, 5)

# Example 2: Low Compliance (ARDS)
# Vt 400 mL, Pplat 25 cmH2O, PEEP 10 cmH2O
# Cstat = 400 / (25 - 10) = 26.7 mL/cmH2O
static_lung_compliance(400, 25, 10)

cliot documentation built on Dec. 1, 2025, 1:06 a.m.