부산대학교 도서관

Background: Previous studies have shown that pneumoperitoneum transiently reduces venous admixture as assessed by a calculation based on the shunt formula, and increases arterial oxygen tension (PaO2 ) in patients without heart or lung disease. The aim of the present study was to further explore the relationship between ventilation-perfusion (VA /Q) before and during pneumoperitoneum by using the multiple inert gas technique. Methods: Nine patients without heart or lung disease (ASA I), with a mean age of 42 years, scheduled for laparoscopic cholecystectomy were included. After premedication and induction of anaesthesia, radial artery and pulmonary artery catheters were introduced percutaneously. The VA /Q relationships were evaluated by the multiple inert gas elimination technique before and during pneumoperitoneum to obtain a direct measure of the pulmonary shunt. Results: Induction of pneumoperitoneum decreased the pulmonary shunt from 5.8 (4.5) to 4.1 (3.2)% (P <0.05) and increased PaO2 from 21.7 (5.9) to 24.7 (4.8) kPa (P <0.01). During surgery, the shunt increased from 3.2 (2.8) to 5.2 (3.4)% to the same level as before pneumoperitoneum induction. No area with low VA /Q was seen. Dead space ventilation amounted to 20.0 (1.2)% in the supine position and did not change during the investigation. Conclusions: In patients without heart or lung disease, pneumoperitoneum at an intra-abdominal pressure level of 11–13 mmHg causes a transient reduction of the pulmonary shunt. The mechanisms underlying the present finding remain to be elucidated. [ABSTRACT FROM AUTHOR]