MONITORING AND REVERSAL OF NEUROMUSCULAR BLOCKADE: A COMPARISON OF CLINICAL VERSUS QUALITATIVE ASSESSMENTS

MONITORING AND REVERSAL OF NEUROMUSCULAR BLOCKADE: A COMPARISON OF CLINICAL VERSUS QUALITATIVE ASSESSMENTS

Abstract

Background: Inadequate recovery from neuromuscular blockade also referred to as residual paralysis has been strongly associated with the use of NMBD especially long-acting neuromuscular blocking drug (NMBD) when clinical test such as head-lift for 5 seconds were used for confirmation of adequate recovery of neuromuscular function. More recently subjective (visual/ tactile) monitoring of NMBD with the aid of peripheral nerve stimulator (PNS) in the peri-operative period has not been found to confer any added advantage in the reduction of residual paralysis when used intraoperatively for monitoring of NMBD.
Objectives: This study aimed to compare suitable method between clinical assessment and subjective assessment for monitoring and reversal of neuromuscular block in seventy American Society of Anaesthesiologists (ASA) I and II patients using safe extubation time interval, time to achieve adequate neuromuscular function and frequency of residual paralysis between the two groups.
Methods: This randomized controlled double-blinded study conducted at the Lagos State University Teaching Hospital (LASUTH) comprised of two groups of 35 surgical patients each (Control group – clinical test and Study group – nerve stimulator). Induction of anaesthesia was achieved with intravenous propofol 2.5mg/kg and intravenous fentanyl 1.5 μg/kg after pre-oxygenation for 5 minutes. Airway was secured with endotracheal tube after administration of intravenous pancuronium 0.1mg/kg and onset of intubation noted and compared between the two groups. Anaesthesia was maintained with halothane 0.75% in 100% oxygen and all patients were ventilated mechanically.
Results: The incidence of residual paralysis after 30 minutes in the recovery room was 30% in both groups. The incidence of residual in clinical assessment group was 43% while the incidence in peripheral nerve stimulator group was 17% (p = 0.001). The mean time interval in minutes for onset of intubation in the clinical assessment group was 2.46 ± 1.31 minutes, the mean time interval in minutes for onset of intubation in the PNS group was 3.49 ± 1.07 minutes (p = 0.001). The mean extubation time interval in minutes for the both control and study group was 11.36 ± 2.71 and 9.28 ± 2.57 minutes respectively (p = 0.01). Mean time interval to achieve adequate recovery of neuromuscular function in minutes for the control group was 41.36 ± 6.08 minutes while the mean time interval of 39.28 ± 3.61 minutes was recorded for the study group (p = 0.013).
Twenty (57.7%) patients in the control group and eight (22.9%) patients in the study group at a TOFC count of 4 had a TOF ratio of less than 0.7 (70%) at 20 minutes. Fifteen (42.9%) patients in the control group and six (17.1%) patients in the study group at a TOFC count of 4 had a TOF ratio of less than 0.7 (70%) at 30 minutes. This result shows a statistically significant difference between the two groups (p = 0.003).
A total number of twenty one patients (30%) had complications associated with residual paralysis in the two groups at TOFC of 4. Fifteen (43%) patients in the control group had hypoxia (oxygen saturation of < 92% on room air oxygen) and six (17%) of the patient in the study group (p = 0.001). Fourteen (66%) patients had hypoxia at SpO2 ≤ 92% on room air oxygen in both groups, nine (64%) in the control group and five (36%) in the study group (p > 0.05). Four patients (19%) had irregular shallow breathing in both groups, three patients in the control group and one patient in the study group, three patients with irregular breathing was resolved by supplemental facemask oxygen and one re-intubated and manually ventilated in the operating room. Three (14%) of the patients in the control group had hypoventilation at RR of less than 8 cycles/minutes that was resolved with re-intubation and manual ventilation in the operating room. None of the patients had aspiration pneumonitis from residual paralysis in the recovery room and there was no atelectasis recorded in the patients on the ward.
Conclusions: A high disparity in the incidence of residual paralysis was observed between the two groups in this study. The incidence of residual was more in the control group that was monitored with clinical test than in the study group monitored subjectively (tactile) assessment with PNS. The study group patients recorded faster recovery of neuromuscular function than the control group comparing the time interval to achieve adequate neuromuscular and extubation time interval. This study clearly demonstrated the advantages of PNS monitoring (subjectively) over clinical assessment in the reversal and monitoring of neuromuscular block. Surveys have shown lack of routine use of PNS monitors by Anaesthetist for monitoring of neuromuscular block due to complexity, fragility and time to set it up and in poor resource country “cost.” There is a need for careful re-examination and re-evaluation of the principles regarding monitoring and reversal of neuromuscular blockade in our sub-region when NMBD are administered.

MONITORING AND REVERSAL OF NEUROMUSCULAR BLOCKADE: A COMPARISON OF CLINICAL VERSUS QUALITATIVE ASSESSMENTS

Sharing is caring!