Influence of variations in arterial PCO2 on surgical conditions during laparoscopic retroperitoneal surgery

Abstract

BackgroundAlthough deep neuromuscular block (post-tetanic-count 1-2 twitches) improves surgical conditions during laparoscopic retroperitoneal surgery compared with standard block (train-of-four 1-2 twitches), the quality of surgical conditions varies widely, often related to diaphragmatic contractions. Hypocapnia may improve surgical conditions. Therefore we studied the effect of changes in arterial carbon dioxide concentrations on surgical conditions in patients undergoing laparoscopic surgery under general anaesthesia and deep neuromuscular block. MethodsForty patients undergoing elective laparoscopic surgery for prostatectomy or nephrectomy received propofol/remifentanil anaesthesia and deep neuromuscular block with rocuronium. Patients were randomized to surgery under hypocapnic or hypercapnic conditions. During surgery, the surgical conditions were evaluated using the 5-point Leiden-Surgical Rating Scale (L-SRS) ranging from 1 (extremely poor conditions) to 5 (optimal conditions) by the surgeon, who was blinded to group. ResultsMean (sd) arterial carbon dioxide concentrations were 4.5 (0.6) [range: 3.8–5.6] kPa under hypocapnic and 6.9 (0.6) [6.1–8.1] kPa under hypercapnic conditions. The L-SRS did not differ between groups: 4.84 (0.4) [4-5] in hypocapnia and 4.77 (0.4) [3.9–5] in hypercapnia. Ninety-nine percent of ratings were good or excellent irrespective of treatment. ConclusionsDeep neuromuscular block provides good to optimal surgical conditions in laparoscopic retroperitoneal urological surgery, independent of the level of arterial PCO2. Clinical trial registrationNCT01968447.