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Erschienen in:
01.11.2009
Effect of different intra-abdominal pressure levels on QT dispersion in patients undergoing laparoscopic cholecystectomy
Erschienen in: Surgical Endoscopy | Ausgabe 11/2009
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Background
Hemodynamic changes caused by carbon dioxide (CO2) insufflation occur frequently in patients who undergo laparoscopic surgery. One indicator of these changes is corrected QT dispersion (QTcd), an index of myocardial function. Prolongation of QTcd has been associated with cardiovascular morbidity and mortality. We compared the effects of high-pressure (15 mmHg) and low-pressure (7 mmHg) CO2 pneumoperitoneums on the QT interval, the rate-corrected QT interval (QTc), the QT dispersion (QTd), and the corrected QT dispersion (QTcd) during laparoscopic cholecystectomy.
Methods
Twenty consecutive patients were in a low-pressure pneumoperitoneum group and 32 were in a high-pressure pneumoperitoneum group. A 12-lead electrocardiogram was used to monitor cardiac variables. In all patients, serial electrocardiograms were recorded before anesthesia induction (baseline), immediately after the pneumoperitoneum had been created, every 15 minutes during CO2 insufflation, and 5 minutes after deflation. Two observers measured the QT intervals independently, and the QTcd was calculated using Bazett’s formula.
Results
The QT interval and the QTc interval did not change significantly during the study in either group. The QTd and QTcd in the high-pressure pneumoperitoneum group increased significantly during CO2 insufflation and were significantly higher in the high-pressure pneumoperitoneum group compared with the low-pressure pneumoperitoneum group. Changes caused by CO2 insufflation were reversible.
Conclusions
Statistically significant increases of QTd and QTcd, which are associated with an increased risk of arrhythmias and cardiac events, occur during CO2 insufflation in both high-pressure and low-pressure pneumoperitoneums. QTd and QTcd were significantly higher in the high-pressure pneumoperitoneum group than they were in the low-pressure pneumoperitoneum group. QT interval changes were not related to anesthetic agents, surgical stress, hypercapnia, or duration of CO2 insufflation. Increased intra-abdominal pressure may have caused these changes.