Expiratory flow limitation in morbidly obese postoperative mechanically ventilated patients.

Full Abstract

Although obesity promotes tidal expiratory flow limitation (EFL), with concurrent dynamic hyperinflation (DH), intrinsic PEEP (PEEPi) and risk of low lung volume injury, the prevalence and magnitude of EFL, DH and PEEPi have not yet been studied in mechanically ventilated morbidly obese subjects. In 15 postoperative mechanically ventilated morbidly obese subjects, we assessed the prevalence of EFL [using the negative expiratory pressure (NEP) technique], PEEPi, DH, respiratory mechanics, arterial oxygenation and PEEPi inequality index as well as the levels of PEEP required to abolish EFL. In supine position at zero PEEP, 10 patients exhibited EFL with a significantly higher PEEPi and DH and a significantly lower PEEPi inequality index than found in the five non-EFL (NEFL) subjects. Impaired gas exchange was found in all cases without significant differences between the EFL and NEFL subjects. Application of 7.5 +/- 2.5 cm H2O of PEEP (range: 4-16) abolished EFL with a reduction of PEEPi and DH and an increase in FRC and the PEEPi inequality index but no significant effect on gas exchange. The present study indicates that: (a) on zero PEEP, EFL is present in most postoperative mechanically ventilated morbidly obese subjects; (b) EFL (and concurrent risk of low lung volume injury) is abolished with appropriate levels of PEEP; and (c) impaired gas exchange is common in these patients, probably mainly due to atelectasis.

Author information

Author/s: Koutsoukou, A (A); Koulouris, N (N); Bekos, B (B); Sotiropoulou, C (C); Kosmas, E (E); Papadima, K (K); Roussos, C (C);

Affiliation: Critical Care Department and Pulmonary Services, Evangelismos General Hospital, University of Athens Medical School, Athens, Greece. koutsoukou(-atsign-)yahoo.gr

Journal and publication information

Publication Type: Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't

Journal: Acta anaesthesiologica Scandinavica (Acta Anaesthesiol Scand), published in Denmark. (Language: eng)

Reference: 2004-Oct; vol 48 (issue 9) : pp 1080-8

Dates: Created 2004/09/08; Completed 2004/12/22; Revised 2006/11/15;

PMID: 15352952, status: MEDLINE (last retrieval date: 2/18/2009, IMS Date: )

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