Anaesthesia for day-stay laparoscopy

The effects of neuromuscular block on peak airway pressure and abdominal elastance during pneumoperitoneum

Administration of muscle relaxants is considered as necessary to prevent high intraabdominal and peak inspiratory pressures induced by pneumoperitoneum during laparoscopy. In the present study, we hypothesized that neuromuscular block does not alter pulmonary or abdominal elastic properties in pigs receiving general anesthesia. To test this hypothesis, changes in peak airway pressure and abdominal elastance during intraabdominal CO(2), insufflation from 0 to 15 mm Hg were recorded in anesthetized pigs, with or without muscle relaxants. A 100% increase in peak inspiratory airway pressure was obtained. This was unaffected by neuromuscular block induced by atracurium (13.2 +/- 5.0 mm Hg vs 25.0 +/- 4.8 mm Hg for the control group and 12.6 +/- 5.0 mm Hg vs 23.5 +/- 6.2 mm Hg for the paralyzed group). Abdominal pressure/volume relationships were independent of muscle relaxant administration (calculated elastance was 3.98 +/- 1.56 mm Hg/L without muscle relaxant vs 3.86 +/- 1.37 mmHg/L in the atracurium group). We conclude that high peak inspiratory airway pressures and intraabdominal pressures during laparoscopy are not affected by neuromuscular block. These findings also question the necessity of muscle relaxants in clinical anesthetic practice during laparoscopic surgery.

[Gynecologic laparoscopy with or without curare]

OBJECTIVE

To assess physiological changes and operating conditions during general anaesthesia with or without neuromuscular blockade in patients undergoing gynaecologic laparoscopy.

STUDY DESIGN

Prospective, randomized, double-blind study.

PATIENTS

Fifty non-obese patients, mean age 31 years, randomly allocated into either a group of 25 with curare (AC) or a group of 25 without curare (SC).

METHODS

All patients were anaesthetized with propofol (2.5 mg.kg-1), sufentanil (0.4 microgram.kg-1) midazolam (2 mg) and N2O-O2. In addition, those of the AC group were given atracurium 0.25 mg.kg-1 for intubation, followed by additional boluses to maintain twitch height < 10% of the control value. Blood pressure, heart rate, peak airway pressure, end-tidal carbon dioxide pressure were recorded before and during pneumoperitoneum maintained at a pressure of 15 mmHg. Operating conditions were assessed at 10-min intervals, using a four point scale.

RESULTS

In both groups, blood pressure and heart rate decreased following induction. The decrease in blood pressure was more important in the SC group at 5 min and before pneumoperitoneum (25 vs 15%); P < 0.05). The time course of PETCO2 and peak airway pressures were similar between groups. Operating conditions were not influenced by the muscle relaxant.

CONCLUSIONS

Neuromuscular blockade influences neither most of the clinical haemodynamic and respiratory changes induced by pneumoperitoneum for gynaecologic laparoscopy not the operating conditions.