Efficacy of ultrasound-guided lower extremity nerve block combined with general anesthesia with laryngeal mask airway in patients undergoing total knee arthroplasty

Abstract

Objective To evaluate the efficacy of uhrasound-guided lower extremity nerve block combined with general anesthesia with laryngeal mask airway in patients undergoing total knee arthroplasty.Methods Forty ASA Ⅰ-Ⅲ patients of both sexes,aged 52-80 yr,weighing 67-94 kg,undergoing total knee arthroplasty under general anesthesia,were randomly divided into 2 groups(n=20 each).Group Ⅰ received combined intravenous-inhalational anesthesia with endotracheal tube.Group Ⅱ received lower extremity nerve block guided by ultrasound and then combined intravenous-inhalational anesthesia with laryngeal mask airway.HR was maintained at 50-100bpm,MAP was maintained at the preoperative baseline level(increase or decrease amplitude<20%of the baseline level)during operation and in pestanesthesia care unit(PACU)and vasoaetive drugs(atropine,esmolol,efedrina,urapidil or labetalol)were given when necessary.The patients received patient-controlled intravenous analgesia with tramedol and lornoxicam(background infusion 2 ml/h,bolus dose 1 ml,lockout interval 15 min)after operation and VAS score was maintained at≤2.The requirement for vasoactive drugs during operation and in PACU,PACU stay length,and consumption of analgesics and occurrence of nausea and vomiting within 24 h after operation were recorded.Results Compared with group Ⅰ,the requirement for all vasoaetive drugs during operation and for esmolol,urapidil and labetalol in PACU was significantly reduced,PACU stay length Was significantly shortened,and the consumption of analgesics and incidence of nausea and vomiting were significantly reduced in group Ⅱ(P<0.01).Conclusion Ultrasound-guided lower extremity nerve block combined with general anesthesia with laryngeal mask airway provides better emcacy with fewer complications and less consumption of postoperative analgesics than general anesthesia with endotracheal tube in patients undergoing total knee arthroplasty. Key words: Ultrasonography; Nerve block; Laryngeal masks; Anesthesia,general; Arthroplasty,replacement,knee