Effects of the beach chair position, positive end-expiratory pressure, and pneumoperitoneum on respiratory function in morbidly obese patients during anesthesia and paralysis.

Abstract

BACKGROUND:

The authors studied the effects of the beach chair (BC) position, 10 cm H2O positive end-expiratory pressure (PEEP), and pneumoperitoneum on respiratory function in morbidly obese patients undergoing laparoscopic gastric banding.

METHODS:

The authors studied 20 patients (body mass index 42 +/- 5 kg/m2) during the supine and BC positions, before and after pneumoperitoneum was instituted (13.6 +/- 1.2 mmHg). PEEP was applied during each combination of position and pneumoperitoneum. The authors measured elastance (E,rs) of the respiratory system, end-expiratory lung volume (helium technique), and arterial oxygen tension. Pressure-volume curves were also taken (occlusion technique). Patients were paralyzed during total intravenous anesthesia. Tidal volume (10.5 +/- 1 ml/kg ideal body weight) and respiratory rate (11 +/- 1 breaths/min) were kept constant throughout.

RESULTS:

In the supine position, respiratory function was abnormal: E,rs was 21.71 +/- 5.26 cm H2O/l, and end-expiratory lung volume was 0.46 +/- 0.1 l. Both the BC position and PEEP improved E,rs (P < 0.01). End-expiratory lung volume almost doubled (0.83 +/- 0.3 and 0.85 +/- 0.3 l, BC and PEEP, respectively; P < 0.01 vs. supine zero end-expiratory pressure), with no evidence of lung recruitment (0.04 +/- 0.1 l in the supine and 0.07 +/- 0.2 in the BC position). PEEP was associated with higher airway pressures than the BC position (22.1 +/- 2.01 vs. 13.8 +/- 1.8 cm H2O; P < 0.01). Pneumoperitoneum further worsened E,rs (31.59 +/- 6.73; P < 0.01) and end-expiratory lung volume (0.35 +/- 0.1 l; P < 0.01). Changes of lung volume correlated with changes of oxygenation (linear regression, R2 = 0.524, P < 0.001) so that during pneumoperitoneum, only the combination of the BC position and PEEP improved oxygenation.

CONCLUSIONS:

The BC position and PEEP counteracted the major derangements of respiratory function produced by anesthesia and paralysis. During pneumoperitoneum, only the combination of the two maneuvers improved oxygenation.

• Authors: Franco Valenza, Federica Vagginelli, Alberto Tiby, Silvia Francesconi, Giulio Ronzoni, Massimiliano Guglielmi, Marco Zappa, Ezio Lattuada, Luciano Gattinoni
• Journal: Anesthesiology (Anesthesiology) Vol. 107 Issue 5 Pg. 725-32 (Nov 2007) ISSN: 0003-3022 [Print] United States
• PMID: 18073547 (Publication Type: Clinical Trial, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Oxygen

Topics

• Adult
• Anesthesia, Intravenous
• Blood Gas Analysis
• Blood Pressure
• Body Mass Index
• Female
• Gastroplasty (methods)
• Heart Rate
• Humans
• Laparoscopy
• Lung Volume Measurements
• Male
• Obesity, Morbid (physiopathology, surgery)
• Oxygen (blood)
• Paralysis (chemically induced)
• Pneumoperitoneum, Artificial (methods, statistics & numerical data)
• Positive-Pressure Respiration (methods, statistics & numerical data)
• Posture
• Respiration
• Supine Position
• Tidal Volume