permissive hypercapnia
A lung-protective strategy allowing elevated CO2 levels to avoid ventilator-induced lung injury from high pressures or volumes.
Full Definition
Permissive hypercapnia is a ventilatory strategy that accepts higher than normal CO2 levels (hypercapnia) to avoid potentially injurious high airway pressures or tidal volumes. This approach prioritizes lung protection over normal blood gas values, typically allowing PaCO2 to rise to 50-80 mmHg or pH to decrease to 7.20-7.25. The strategy is commonly employed in ARDS management, severe asthma, and other conditions where conventional ventilation might cause barotrauma or volutrauma. While generally well-tolerated, permissive hypercapnia is contraindicated in patients with increased intracranial pressure, severe cardiac dysfunction, or significant metabolic acidosis.
Usage
Usage note: Distinguish from pathological hypercapnia; requires specific contraindication screening.
In Context
- "Permissive hypercapnia was employed to maintain plateau pressures below 30 cmH2O in this ARDS patient." — Lung-protective ventilation protocol
- "The patient's pH of 7.22 was acceptable under the permissive hypercapnia strategy." — Blood gas interpretation note