LAUSR

Supplemental Digital Content is available in the text BACKGROUND Previous studies have reported an association between the use of neuromuscular blocking (NMB) agents and postoperative pulmonary complications. Postoperative pulmonary function is a key indicator for postoperative pulmonary complications. Several sites can be used to assess depth and recovery from NMB. OBJECTIVES To investigate postoperative pulmonary function change in relation to train-of-four measurements at the adductor pollicis and corrugator supercilii muscles, and anaesthesia-related variables in orthopaedic patients undergoing hip or knee arthroplasty. DESIGN Observational study. SETTING University hospital. PATIENTS Orthopaedic patients undergoing hip or knee arthroplasty. MAIN OUTCOME MEASURES Postoperative pulmonary function tests in the postanaesthesia care unit. METHODS Patients scheduled for elective hip or knee arthroplasty received simultaneous corrugator supercilii and adductor pollicis measurements during anaesthesia conducted according to clinical standards. Forced expiratory volume in 1 s and forced vital capacity (FVC) were measured at the time of inclusion and postoperatively on the postanaesthesia care unit. Linear regression analysis was performed for association between risk factors and pulmonary function change. RESULTS A total of 35 patients were included. After exclusions, 20 patients remained for final analysis. Corrugator supercilii showed earlier NMB recovery than adductor pollicis. FVC decreased significantly after surgery from 2.9 ± 1.0 to 2.3 ± 1.0 (P < 0.01) and forced expiratory volume in 1 s decreased from 2.3 ± 0.9 to 1.6 ± 0.8 l (P < 0.01). Patient age was the only factor significantly related to FVC decrease after surgery (P = 0.019) with a cut-off value of 65 years. CONCLUSION Both corrugator supercilii and adductor pollicis failed to indicate recovery of pulmonary function after NMB. Age seems to be a risk factor for postoperative decline in pulmonary function. TRIAL REGISTRATION German Clinical Trials registry, DRKS-ID: DRKS00014305.