Residual neuromuscular block in the postanesthesia care unit: incidence, risk factors, and effect of neuromuscular monitoring and reversal agents.

BACKGROUND: The aim of this study was to determine the incidence of residual neuromuscular block (RNMB) in a tertiary care hospital. Secondary goals were to examine the characteristics of the use of intraoperative neuromuscular monitoring (NMM) and different reversal agents by the attending anesthesiologists, and to determine the factors related to the patient and perioperative processes on the development of RNMB.

METHODS: The patients' arrival time at the postanesthesia care unit was accepted as point zero (T0). The acceleromyography of the patients' adductor pollicis muscle was monitored for NMM. Train of four ratios (TOFRs) were recorded at 0, 10, 20, and 30 min. A TOFR < 0.9 was defined as RNMB. Patients' demographic and perioperative data were also recorded.

RESULTS: A total of 216 patients completed the study. RNMB was observed in 47 patients (21.8%). Seventy-eight patients (36%) were followed up with NMM. Neostigmine and sugammadex were used in 174 (80.5%) and 42 (19.5%) patients, respectively, and they were both underdosed (21.2 ± 3.0 mcg/kg and 1.5 ± 0.7 mg/kg, respectively). Use of neostigmine and absence of NMM were risk factors for RNMB (p: 0.01 and 0.001, respectively) along with the number of additional doses (>1 doses, p ≤ 0.02) and the timing of the last dose of rocuronium (<88 min, p ≤ 0.01). None of the patients who received both NMM and sugammadex experienced RNMB.

DISCUSSION: The RNMB incidence was found to be 21.8%. The main reasons of it were the lack of intraoperative NMM and inappropriate use of reversal agents. Despite strong recommendations, the use of NMM is still insufficient and reversal agents are still underdosed.