permissive hypercapnia


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permissive hypercapnia

Critical care An approach to management of acute respiratory failure in which the tidal volume–VT is lower–5-8 mL/kg than that conventionally used–10-15 mL/kg, the arterial Pco2 is allowed to rise above the 'normal' of 40 mm Hg, and no attempts are made to compensate for subsequent changes in blood pH–respiratory acidosis, the deleterious effects of which may have been overestimated
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.

permissive hypercapnia

Intentional limiting of airway pressures and tidal volumes during mechanical ventilation, thereby allowing PaCO2 to rise above normal, in order to minimize the risk of lung injury.

CAUTION!

Permissive hypercapnia should be avoided in patients who may not tolerate high carbon dioxide levels or acidosis, e.g., patients with sickle cell anemia or those with high intracranial pressures.
See also: hypercapnia
Medical Dictionary, © 2009 Farlex and Partners
References in periodicals archive ?
The mortality rates can be reduced by the application of permissive hypercapnia and a lung-preserving MV strategy, such as low VT and optimal PEEP support, which will keep the alveoli open.
Low mortality rate in adult respiratory distress syndrome using low-volume, pressure-limited ventilation with permissive hypercapnia: a prospective study.
Pros and cons of permissive hypercapnia in patients with subarachnoid haemorrhage and ARDS.
Effects of permissive hypercapnia on transient global cerebral ischemia-reperfusion injury in rats.
In a more recent editorial discussing therapeutic hypercapnia and sepsis, (3) Swenson, while acknowledging that permissive hypercapnia can have a positive effect in some cases, posed a caution: There is a concern that "therapeutic hypercapnia may impair host defenses against pathogens surely to be encountered by mechanically ventilated patients." (3)
Swenson (3) also gives some important historical context to the issue of permissive hypercapnia, pointing out that when blood-gas analysis became available almost 60 years ago, it "revealed surprisingly profound hypercapnia." An example he notes: "a (p[CO.sub.2] (a) >150 mmHg) [with a pH of 7] without negative consequences involving one-lung ventilation." And yet, with this ability to measure blood-gas parameters, it was almost 30 years before permissive hypercapnia was studied, he adds.
A number of measures are taken to establish permissive hypercapnia. The PaCO2 is permitted to increase, while the pH is allowed to decrease as a result of sedating the patient.
Tromethamine buffer modifies the depressant effect of permissive hypercapnia on myocardial contractility in patients with acute respiratory distress syndrome.
Permissive hypercapnia in ARDS and its effect on tissue oxygenation.