Anesthesia for laparoscopic surgery

Spinal-general anaesthesia decreases neuroendocrine stress response in laparoscopic cholecystectomy

OBJECTIVE

A randomized clinical study to compare the stress response to laparoscopic cholecystectomy during spinal-general anaesthesia and epidural- general anaesthesia.

METHODS

Women undergoing elective laparoscopic chole cystectomy were assigned to receive either spinal anaesthesia (SA group; n = 12) or epidural anaesthesia (EA group; n = 12), in addition to general anaesthesia. Plasma concentrations of cortisol, adrenocorticotrophic hormone (ACTH), noradrenaline, adrenaline and total catecholamines were measured pre- and intraoperatively.

RESULTS

Intraoperative cortisol, noradrenaline and total catecholamine levels were significantly lower in the SA group compared with the EA group. When pre- and intraoperative values were compared, the SA group showed a decrease in adrenaline, noradrenaline and total catecholamine levels, and the EA group showed an increase in ACTH and noradrenaline levels.

CONCLUSIONS

The type of regional anaesthesia significantly affected the stress response: spinal anaesthesia produced a more favourable endocrine response than epidural anaesthesia. Spinal-general anaesthesia may reduce postoperative morbidity in laparoscopic cholecystectomy.

Effects of adding small amounts of oxygen to a carbon dioxide-pneumoperitoneum of increasing pressure in rabbit ventilation models

OBJECTIVE

To evaluate the metabolic consequences of the addition of oxygen to the CO(2)-pneumoperitoneum.

DESIGN

Prospective randomized study in rabbits. After 30 minutes of ventilation pneumoperitoneum was maintained for 90 minutes with pure CO(2) or CO(2) with 2% or 6% of oxygen. The intraperitoneal pressure was increased from 10 to 15 and 20 mm Hg every 30 minutes. Ventilation rate was either fixed or a progressive hyperventilation. End points were changes in arterial blood gases (Pco(2), Po(2)), pH, acid-base balance (actual base excess [ABE], standard bicarbonate [SBC], standard base excess [SBE], hydrogen carbonate [HCO(3)(-)], concentration of total carbon dioxide [Tco(2)]); oxygen and oximetry (oxyhemoglobin [O(2)Hb], oxygen saturation [So(2)], reduced hemoglobin [RHb], total oxygen concentration [To(2)], and oxygen tension at half saturation assessing hemoglobin oxygen affinity [p50]); and lactate concentrations assayed every 15 minutes.

SETTING

University research center.

ANIMALS

Twenty-four adult female New Zealand white rabbits.

INTERVENTION(S)

Anesthesia, mechanical ventilation, and pneumoperitoneum.

RESULT(S)

The effects of CO(2)-pneumoperitoneum on all end points increased with the elevated intraperitoneal pressure and were more pronounced when ventilation was fixed. Changes were less when 2% or 6% of oxygen had been added to the CO(2)-pneumoperitoneum. With use of logistic regression, the addition of oxygen, intraperitoneal pressure, and ventilation were found to be independent variables affecting Pco(2), pH, ABE, SBE, HCO(3)(-), O(2)Hb, So(2), p50, and end-tidal CO(2).

CONCLUSION(S)

The metabolic consequences of the combined effect of increased intraperitoneal pressure and CO(2)-pneumoperitoneum were less when 2% to 6% of oxygen was added or when animals were hyperventilated. We suggest that metabolic and mesothelial hypoxemia caused by CO(2) absorption can be reduced by adding small amounts of oxygen and by hyperventilation.