Femoral nerve blocks for the treatment of acute prehospital pain: a systematic reviewwith meta-analysis.

BACKGROUND: Pain management is one of the most importantinterventions in the emergency medical services. The femoral nerve block (FNB) is,amongst other things, indicatedfor pre- and post-operative painmanagementfor patients withfemoral fractures but its role in the prehospital setting has not beendetermined.The aim of this review was to assess the effect and safety of the FNB in comparison to other formsof analgesia (or no treatment) for managingacute lower extremity painin adult patients in the prehospital setting. METHODS: A systematic review (PROSPERO registration (CRD42018114399))was conducted. The Cochrane and GRADE methods were used to assess outcomes. Two authors independently reviewed eachstudy for eligibility, extracted the data and performed risk of bias assessments. RESULTS: Four studies with a total of 252 patients were included. Two RCTs (114 patients) showed thatFNB may reduce pain moreeffectively than metamizole (mean difference 32 mm on a 100 mm VAS (95% CI 24 to 40)). One RCT (48 patients) compared the FNB with lidocaine and magnesium sulphate to FNB with lidocaine aloneandwasonly included here for information regarding adverse effects. Onecase series included 90 patients.Few adverse events werereportedin the included studies.The certainty of evidence was very low. We found no studies comparing FNB to inhaled analgesics, opioids or ketamine. CONCLUSIONS: Evidence regarding the effectiveness and adverse effects ofprehospital FNB is limited.Studiescomparing prehospital FNB to inhaled analgesics, opioids or ketamine are lacking. EDITORIAL COMMENT: In this systematic review, use of femoral nerve blocks in the prehospital setting was assessed. The quantity and quality of evidence was very low with no firm evidence for benefit or harm, and more research is needed.