Intrinsic PEEP During Mechanical Ventilation of Patients With Obesity

Intrinsic PEEP During Mechanical Ventilation of Patients With Obesity. Influence of Low Respiratory Rate With Unchanged Minute Volume.

It is demonstrated that expiratory flow limitation and as a consequence, intrinsic positive end-expiratory pressure (PEEP) is present in grossly obese subjects especially in the supine position. The investigators tried to investigate the effect of low respiratory rate and high tidal volume on the intrinsic PEEP and gas exchange for obese subjects undergoing general anesthesia.

Impaired gas exchange is a common anesthetic problem in obese subjects. It is demonstrated that expiratory flow limitation and as a consequence, intrinsic positive end-expiratory pressure (PEEPi) is present in grossly obese subjects especially in the supine position. It is known that there is a significant negative correlation between PEEPi present and PaO2. Therefore, the investigators postulated that if the reduce the PEEPi by reducing the respiratory rate in obese subjects, the impaired gas exchange might improve.

The investigators tried to research the effect of low respiratory rate and high tidal volume on the intrinsic PEEP and gas exchange for obese subjects undergoing general anesthesia.

Inclusion Criteria:

• ASA class I or II obesity, Body-mass index > 27.5 undergoing laparoscopic cholecystectomy

Exclusion Criteria:

• patients with severe cardiopulmonary disease peak inspiratory pressure > 40 in the study setting