Monitoring intraoperative neuromuscular blockade and blood pressure with one device (TOF-Cuff): A comparative study with mechanomyography and invasive blood pressure

Methods for Clinical Monitoring of Neuromuscular Transmission in Anesthesiology - A Review

The administration of general anesthesia is a crucial aspect of surgery. However, it can pose significant risks to patients, such as respiratory depression and prolonged neuromuscular blockade. To avoid such complications, it is essential to monitor neuromuscular transmission during anesthesia. While clinical tests have been used for decades to evaluate muscle function, they are now known to be unreliable, and relying on them increases the risk of postoperative complications. Thankfully, there are now six methods available for neuromuscular monitoring during anesthesia: mechanomyography, acceleromyography, electromyography, kinemyography, phonomyography, and compressomyography. Each of these methods differs in terms of their approach and methodology, and their importance in clinical practice varies accordingly. Mechanomyography involves measuring the mechanical response of a muscle to nerve stimulation, while acceleromyography measures the acceleration of muscle contraction. Electromyography records the electrical activity of muscles, while kinemyography tracks muscle movement. Phonomyography records the sound waves produced by contracting muscles, and compressomyography involves monitoring the pressure changes in a muscle during contraction. Overall, understanding the differences between these methods and their clinical significance is crucial for anesthesiologists. This review aims to provide an updated understanding of the current methods available for neuromuscular monitoring during anesthesia, so that anesthesiologists can make informed decisions about patient care and reduce the risk of postoperative complications.

Quantitative Neuromuscular Monitoring and Postoperative Outcomes: A Narrative Review

Over the past five decades, quantitative neuromuscular monitoring devices have been used to examine the incidence of postoperative residual neuromuscular block in international clinical practices, and to determine their role in reducing the risk of residual neuromuscular block and associated adverse clinical outcomes. Several clinical trials and a recent meta-analysis have documented that the intraoperative application of quantitative monitoring significantly reduces the risk of residual neuromuscular blockade in the operating room and postanesthesia care unit. In addition, emerging data show that quantitative monitoring minimizes the risk of adverse clinical events, such as unplanned postoperative reintubations, hypoxemia, and postoperative episodes of airway obstruction associated with incomplete neuromuscular recovery, and may improve postoperative respiratory outcomes. Several international anesthesia societies have recommended that quantitative monitoring be performed whenever a neuromuscular blocking agent is administered. Therefore, a comprehensive review of the literature was performed to determine the potential benefits of quantitative monitoring in the perioperative setting.

Clinical Practice Guideline for the Management of Neuromuscular Blockade: What Are the Recommendations in the USA and Other Countries?

Purpose of Review

This review addresses various societal guidelines, standards, and consensus statements regarding optimal neuromuscular blockade management. We discuss the historical evolution of neuromuscular management as a means of identifying possible future trends.

Recent Findings

While a recent international panel of experts has called for abandoning clinical assessment and subjective evaluation using a peripheral nerve stimulator in favor of adopting quantitative monitoring, few anesthesia societies mandate similar practices at the moment.

Summary

The current status of neuromuscular monitoring in the world is still variable and unsatisfactory. Nevertheless, a positive trend can be observed in the anesthesia community to adopt and learn this neglected technique. The development of user-friendly monitoring devices should also help this process, but anesthesia national societies still need to do a lot to replace outdated and substandard practices.

Neuromuscular monitoring during modified rapid sequence induction: A comparison of TOF-Cuff® and TOF-Scan®

BACKGROUND

Acceleromyometry is the clinical standard for quantitative neuromuscular monitoring, mostly using the stimulation pattern train-of-four (TOF). TOF-Cuff®, a recently introduced neuromuscular monitor with stimulating electrodes integrated within a blood pressure cuff, assesses the muscular response in the upper arm.

METHODS

The time from administration of a neuromuscular blocking agent to TOF-ratio 0% during modified rapid sequence induction was compared between TOF-Cuff® and acceleromyometry (TOF-Scan®). Included were 26 adults with body mass index <35 kg/m². TOF-Scan® and TOF-Cuff® were simultaneously fitted on patients' opposite arms. The mean difference to TOF-ratio 0% was compared using the one sample t-test (p < 0.05) and Bland-Altman plots.

RESULTS

After anesthesia induction, atracurium 0.9 mg/kg (±0.08) i.v. was administered. The mean time to TOF ratio 0% for TOF-Scan® was 140.4 s (±34.3), and 132.7 s (±32.5) for TOF-Cuff®, with a mean difference of 5.4 (95% CI: -9.9 to 20.7, p = 0.472). The maximum difference between the two modalities was 135 s when the TOF-Cuff® was faster and 60 s when the TOF-Scan® was faster.

CONCLUSIONS

No statistically significant systematic difference was found between TOF-Scan® and TOF-Cuff®. However, there was high variability and wide limits of agreement. The two devices cannot be used interchangeably.

Assessment of spontaneous neuromuscular recovery: A comparison of the TOF-Cuff® with the TOF Watch SX®

BACKGROUND

TOF-Cuff^® is a modified blood pressure cuff used to monitor neuromuscular block. We compared the assessment of spontaneous neuromuscular recovery between TOF-Cuff^® (test device) and TOF Watch SX^® (reference device).

METHODS

Forty patients aged 18-65 years undergoing elective surgery were enrolled. TOF-Cuff^® was installed on an upper arm and the TOF Watch SX^® on the thumb of the opposite side. Anaesthesia was induced and maintained with intravenous propofol and sufentanil. After induction, the devices were calibrated and continuous train-of-four (TOF) stimulation was started. A single intravenous dose of rocuronium (0.6 mg kg^-1 ) was administered for intubation. The primary outcome was total recovery time (time in minutes from the injection of rocuronium to a normalized TOF ratio of 90%). Agreement between the two devices was calculated using mean difference and limits of agreement.

RESULTS

The primary outcome could be analysed in 27 patients because of 13 exclusions due to neuromuscular block reversal for shorter procedure surgical time, necessity of reinjection of rocuronium or technical failures of one of the two devices. Median total recovery time with the test device was 45 minutes (interquartile range [IQR] 38.5-61.5) and 63 minutes (IQR 51.1-74.5) with the reference device. Total recovery time with the test device was on average 16.4 minutes shorter (limits of agreement, -6.1 to 39); increasing total recovery time was associated with increasing difference. The TOF ratio of the reference device was on average 0.59 (SD 0.23) when the test device indicated complete recovery. The TOF ratio of the test device was on average 0.98 (SD 0.03) when the reference device indicated complete recovery.

CONCLUSION

When compared with the TOF Watch SX^® , TOF-Cuff^® overestimates spontaneous recovery of a rocuronium-induced neuromuscular block.

Placement of TOF-Cuff® on the lower leg for neuromuscular and blood pressure monitoring during anesthetic induction for shoulder surgeries

The aim of this study was to compare two devices for neuromuscular monitoring during anesthetic induction. TOF-Cuff^® was installed on the lower leg stimulating the tibial nerve, while the more conventional TOF-Scan^® was installed over the ulnar nerve at the wrist.

Methods

Twenty adult patients were enrolled in this prospective, controlled study. Train-of-four (TOF) was recorded every 15 s until TOF ratio of 0%. Mean arterial blood pressure (MAP) was assessed with TOF-Cuff® and with standard anesthesia monitoring from the brachial artery. MAP was measured before and after anesthetic induction. Time to TOF ratio = 0% was compared with one-sample t test and Bland–Altman plots.

Results

Patients received 0.53 ± 0.09 mg atracurium per kg body weight intravenously. Mean time to TOF ratio = 0% was 150.8 s (± 43.7) for TOF-Scan^®, and 174.4 s (± 42.7) for TOF-Cuff^® (p = 0.1356). Bias was − 15.9 (95% confidence interval − 37.5 to 5.6) with 95% limits of agreement of − 95.2 to 63.3. Twenty-five percent of the patients had a technical issue with a TOF-Cuff^® measurement. For MAP, mean difference was 1.4 (95% confidence interval − 2.4 to 5.2) with 95% limits of agreement of − 22.7 to 25.5.

Conclusion

The time from administration of a common dose of atracurium to a TOF ratio of 0% assessed with TOF-Cuff® stimulating the tibial nerve compared to TOF-Scan® stimulating the ulnar nerve showed large limits of agreement in Bland–Altman analysis. There was a high failure rate with TOF-Cuff® measurements on the lower leg.

Enabling Heart Self-Monitoring for All and for AAL-Portable Device within a Complete Telemedicine System

During the last decades there has been a rapidly growing elderly population and the number of patients with chronic heart-related diseases has exploded. Many of them (such as those with congestive heart failure or some types of arrhythmias) require close medical supervision, thus imposing a big burden on healthcare costs in most western economies. Specifically, continuous or frequent Arterial Blood Pressure (ABP) and electrocardiogram (ECG) monitoring are important tools in the follow-up of many of these patients. In this work, we present a novel remote non-ambulatory and clinically validated heart self-monitoring system, which allows ABP and ECG monitoring to effectively identify clinically relevant arrhythmias. The system integrates digital transmission of the ECG and tensiometer measurements, within a patient-comfortable support, easy to recharge and with a multi-function software, all of them aiming to adapt for elderly people. The main novelty is that both physiological variables (ABP and ECG) are simultaneously measured in an ambulatory environment, which to our best knowledge is not readily available in the clinical market. Different processing techniques were implemented to analyze the heart rhythm, including pause detection, rhythm alterations and atrial fibrillation, hence allowing early detection of these diseases. Our results achieved clinical quality both for in-lab hardware testing and for ambulatory scenario validations. The proposed active assisted living (AAL) Sensor-based system is an end-to-end multidisciplinary system, fully connected to a platform and tested by the clinical team from beginning to end.

Neuromuscular monitoring: an update

This review makes an advocacy for neuromuscular blockade monitoring during anaesthesia care, by: (i) describing the fundamental principles of the methods currently available, at the same time emphasizing quantitative recording measurements; (ii) describing the different ways in which muscles respond to the effect of neuromuscular blockade and their use in clinical practice; (iii) presenting results of different studies on timing and agents of neuromuscular block reversal, including a recommendation for sugammadex use and experimental results with calabadion and (iv) in the end emphasizing the need for implementing neuromuscular monitoring as a practice that should be used every time a neuromuscular block is required.