Is deliberate hypotension a safe technique for orthopedic surgery?: a systematic review and meta-analysis of parallel randomized controlled trials

Abstract

Abstract Background Deliberate hypotension has been shown to reduce the intraoperative bleeding and the need for allogeneic blood transfusion, and improve the surgical field, but there is still controversy on its clinical safety. This systematic review was designed to assess the safety and benefits of deliberate hypotension for orthopedic surgery. Methods The review met the requirements of the PRISMA guidelines. The Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, CINAHL, ISI Web of Science, ScienceDirect, and four Chinese databases (China National Knowledge Infrastructure, Wanfang, vip citation database, and updated version of China Biology Medicine disc from January 1, 2000 to January 1, 2019) were searched. All parallel randomized controlled trials comparing the effects of using deliberate hypotension with not using deliberate hypotension on clinical outcomes of patients undergoing orthopedic surgery were selected. The primary outcome was overall mortality. The secondary outcomes were the intraoperative blood loss, blood transfusion volume, and serious adverse postoperative events. Results A total of 30 studies with 36 comparisons (1454 participants) were included in meta-analysis. Two studies with 120 participants reported overall mortality and the result was zero (low-quality evidence). The use of deliberate hypotension reduced the intraoperative blood loss (mean difference, − 376.7; 95% CI − 428.1 to − 325.3; I 2 = 94%; 29 studies, 36 comparisons, and 1398 participants; low-quality evidence) and blood transfusion volume (mean difference, − 242.5; 95% CI − 302.5 to − 182.6; I 2 = 95%; 13 studies, 14 comparisons, and 544 participants; low-quality evidence). Six studies with 286 participants reported the occurrence of serious adverse postoperative events and the result was zero (low-quality evidence). Subgroup analyses according to age groups, controlled mean artery pressure levels, types of orthopedic surgeries, different combinations of other blood conservative method, and hypotensive methods mostly did not explain heterogeneity; significant differences were identified in almost all subgroups. Conclusions Based on the available evidence, it is still unclear whether or not deliberate hypotension is a safe technique for orthopedic surgery due to limited studies with very small sample size, though it may decrease the intraoperative blood loss and blood transfusion volume irrespective of age groups, controlled mean artery pressure levels, types of surgeries, hypotensive methods, or different combinations of other blood conservation strategies. Trial registration PROSPERO CRD42016045480.

Keywords

• Deliberate hypotension
• Orthopedic surgery
• Randomized controlled trial
• Meta-analysis