One of the tools in the Acute Respiratory Distress Syndrome Network is a ratio between the tidal volume and predicted body weight (PBW).
The equations for predicted body weight are those of Devine and McCarron.
Parameters:
(1) tidal volume in mL
(2) sex
(3) body height in inches or centimeters
ideal body weight in kilograms for males =
= 50 + (2.3 * ((height in inches) - 60))
ideal body weight in kilograms for females =
= 45.5 + (2.3 * ((height in inches) - 60))
Alternatively:
ideal body weight in kilograms for males =
= 50 + (0.91 * ((height in cm) - 152.4))
ideal body weight in kilograms for females =
= 45.5 + (0.91 * ((height in cm) - 152.4))
ratio of tidal volume to predicted body weight =
= (tidal volume) / (predicted body weight in kg)
Interpretation:
• The range for the ratio is from 4 to 8 mL per kg, with 6 the usual target.
