Safety and effectiveness of adding fentanyl or sufentanil to spinal anesthesia: systematic review and meta-analysis of randomized controlled trials

Introduction: Spinal infusions of either fentanyl or sufentanil have been reported in interna-tional reports, articles, and scientific events worldwide. This study aimed to determine whether intrathecal fentanyl or sufentanil offers safety in mortality and perioperative adverse events. Methods: MEDLINE (via PubMed), EMBASE, CENTRAL (Cochrane library databases), gray litera-ture, hand-searching, and clinicaltrials.gov were systematically searched. Randomized con -trolled trials with no language, data, or status restrictions were included, comparing the effectiveness and safety of adding spinal lipophilic opioid to local anesthetics (LAs). Data were pooled using the random-effects models or fixed-effect models based on heterogeneity. Results: The initial search retrieved 4469 records; 3241 records were eligible, and 3152 articles were excluded after reading titles and abstracts, with a high agreement rate (98.6%). After read-ing the full texts, 76 articles remained. Spinal fentanyl and sufentanil significantly reduced post-operative pain and opioid consumption, increased analgesia and pruritus. Fentanyl, but not sufentanil, significantly reduced both postoperative nausea and vomiting, and postoperative