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Effect of CO 2 pneumoperitoneum on ventilation‐perfusion relationships during laparoscopic cholecystectomy
Author(s) -
Andersson L.,
Lagerstrand L.,
Thörne A.,
Sollevi A.,
Brodin LÅ.,
OdebergWernerman S.
Publication year - 2002
Publication title -
acta anaesthesiologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.738
H-Index - 107
eISSN - 1399-6576
pISSN - 0001-5172
DOI - 10.1034/j.1399-6576.2002.460513.x
Subject(s) - pneumoperitoneum , medicine , supine position , anesthesia , pulmonary shunt , shunt (medical) , cholecystectomy , insufflation , perfusion , cardiology , surgery , laparoscopy , hemodynamics
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 (PaO 2 ) in patients without heart or lung disease. The aim of the present study was to further explore the relationship between ventilation‐perfusion (V˙ A /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 V˙ A /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 PaO 2 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 V˙ A /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.