Do we have to hyperventilate during laparoscopic surgery?

PURPOSE The purpose of this study was to assess the effects of hyperventilation on patients undergoing laparoscopic surgeries on haemodynamics, partial pressure of carbon dioxide and acid base status. METHODS 60 patients undergoing laparoscopic surgeries under General Anaesthesia were randomized into two groups, "control group" ventilated with tidal volume of 10 ml/kg and respiratory rate of 12/minute and "study group" same tidal volume with respiratory rate of 15/ minute. Hemodynamic variables (heart rate and mean arterial pressure) recorded and End tidal C02, PaC02, pH and Bicarbonate estimation done before, during and after C02 pneumoperitoneum and analyzed. RESULTS There was no significant difference in hemodynamic variables but there was linear increase in ETC02 and PaC02 measurements in higher normal levels in control group (ETC02 33.3+/-3.20, 37.93+/-3.95 and 43.20+/-3.40; PaC02 30.08+/-2.35, 34.80+/-4.01 and 41.94+/-3.66 mmHg before, during, and after pneumoperitoneum respectively) compared to study group in which these parameters were in lower normal levels (ETC02 33.33+/-4.11, 28.00+/-4.10 and 36.73+/-2.49 mmHg and PaC02 31.80+/-2.73, 29.36+/-3.16 and 35.15+/-1.32 mmHg before, during, and after pneumoperitoneum respectively). There was highly significant difference in these parameters when intergroup comparison was done during and after pneumoperitoneum period. pH and bicarbonate levels were within normal limits but there was decreasing tendency towards acidosis side in control group. CONCLUSION 10-15% increment in Minute Volume is beneficial during C02 pneumoperitoneum to prevent adverse effects of hypercarbia and acidosis.