In a recent issue of the European Journal of Anaesthesiology, Madsen et al.1 presented a randomised controlled trial, evaluating the effect of deep neuromuscular blockade and low-pressure pneumoperitoneum in laparoscopic hysterectomy. The authors concluded that deep neuromuscular blockade and low-pressure pneumoperitoneum (8 mmHg) reduced the incidence of postoperative shoulder pain as compared to standard pressure pneumoperitoneum (12 mmHg) with standard neuromuscular blockade. This finding is in accordance with a recent review and meta-analysis, showing that the use of low-pressure pneumoperitoneum correlates with clinically relevant, lower overall and referred shoulder pain scores.2 In this meta-analysis, all included studies were performed with standard neuromuscular blockade regardless of the intraperitoneal pressure. Therefore, it seems reasonable to assume that the use of deep neuromuscular blockade does not influence postoperative pain scores and that it only facilitates the use of low-pressure pneumoperitoneum. However, in a recent study by Castro et al.3 it was shown that sugammadex, in combination with deep neuromuscular blockade, reduced postoperative pain after laparoscopic bariatric surgery.
Based on current evidence, postoperative pain scores may be reduced by the use of low-pressure pneumoperitoneum as well as the use of deep neuromuscular blockade. In our view, the study by Madsen et al.1 does not reveal whether lower referred pain scores after laparoscopy should be attributed to the use of deep neuromuscular blockade, low-pressure pneumoperitoneum or a combination of both. In the discussion section, Madsen et al.1 state that their results were mainly because of the lower insufflation pressure, as there seems no rational explanation for an analgesic effect of deep neuromuscular blockade or sugammadex. Although it remains speculative, deep neuromuscular blockade may in theory have an analgesic effect during laparoscopy. Deep neuromuscular blockade facilitates maximum stretching of abdominal wall muscle fibres during laparoscopy. This leads to an increased abdominal wall compliance that may reduce pressure-related postoperative pain.
In conclusion, current evidence shows that the use of low-pressure pneumoperitoneum reduces pain scores after laparoscopy. The question of whether the use of deep neuromuscular blockade influences postoperative pain scores after laparoscopy remains unanswered. This issue should be pursued in future clinical trials.
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1. Madsen MV, Istre O, Staehr-Rye AK, Springborg HH, Rosenberg J, Lund J, Gätke MR. Postoperative shoulder pain after laparoscopic hysterectomy with deep neuromuscular blockade and low-pressure pneumoperitoneum: a randomised controlled trial. Eur J Anaesthesiol
2. Özdemir-van Brunschot DM, van Laarhoven KC, Scheffer GJ, et al. What is the evidence for the use of low-pressure pneumoperitoneum? A systematic review. Surg Endosc
2015; [Epub ahead of print]. DOI: 10.1007/s00464-015-4454-9.
3. Castro DS Jr, Leão P, Borges S, et al. Sugammadex reduces postoperative pain after laparoscopic bariatric surgery: a randomized trial. Surg Laparosc Endosc Percutan Tech