2023 American Society of Anesthesiologists Practice Guidelines for Monitoring and Antagonism of Neuromuscular Blockade: A Report by the American Society of Anesthesiologists Task Force on Neuromuscular Blockade.

These practice guidelines provide evidence-based recommendations on the management of neuromuscular monitoring and antagonism of neuromuscular blocking agents during and after general anesthesia. The guidance focuses primarily on the type and site of monitoring and the process of antagonizing neuromuscular blockade to reduce residual neuromuscular blockade.

Evaluation of a Protocol for the Management of Maintenance and Reversal of Rocuronium Block Using Neostigmine or Sugammadex.

BACKGROUND: Postoperative residual neuromuscular blockade (PRNB) is defined as an adductor pollicis train-of-four ratio (TOFR) <0.9. It is a common postoperative complication when nondepolarizing muscle relaxants are either not reversed or reversed with neostigmine. PRNB has been reported in 25% to 58% of patients who receive intermediate-acting nondepolarizing muscle relaxants, and it is associated with increased morbidity and decreased patient satisfaction. We conducted a prospective descriptive cohort study during the implementation of a practice guideline that included the selective use of sugammadex or neostigmine. The primary study aim of this pragmatic study was to estimate the incidence of PRNB at arrival to the postanesthesia care unit (PACU) when the practice guideline is followed. METHODS: We enrolled patients undergoing orthopedic or abdominal surgery requiring neuromuscular blockade. Rocuronium administration was guided by surgical requirements and based on ideal body weight, with dose reductions for women and/or age >55 years. Only qualitative monitoring was available to the anesthesia providers, and selection of sugammadex or neostigmine was guided by tactile assessments of the response to train-of-four (TOF) stimulation by a peripheral nerve stimulator. Neostigmine was administered if no fade was detected in the TOF response at the thumb. Deeper blocks were reversed with sugammadex. The prespecified primary and secondary end points were the incidence of PRNB at arrival to the PACU, defined as a normalized TOFR (nTOFR) < 0.9, and severe PRNB, defined as nTOFR <0.7 on arrival to the PACU. Anesthesia providers were blinded to all quantitative measurements made by research staff. RESULTS: Analysis included 163 patients, and 145 underwent orthopedic and 18 abdominal surgeries. Of the 163 patients, 92 (56%) were reversed with neostigmine and 71 (44%) with sugammadex. The overall incidence of PRNB at PACU arrival was 5 of 163 or 3% (95% confidence interval [CI], 1-7). The incidence of severe PRNB in PACU was 1% (95% CI, 0-4). Three of the 5 subjects with PRNB had TOFR <0.4 at time of reversal but were given neostigmine since anesthesia providers detected no fade by qualitative assessment. CONCLUSIONS: The use of a protocol that specifies rocuronium dosing and selective use of sugammadex versus neostigmine based on qualitative assessment of TOF count and fade allowed us to achieve an incidence of PRNB of 3% (95% CI, 1-7) at PACU arrival. Quantitative monitoring may be needed to further reduce this incidence.

Management of Muscle Relaxation With Rocuronium and Reversal With Neostigmine or Sugammadex Guided by Quantitative Neuromuscular Monitoring.

BACKGROUND: The optimal pharmacological reversal strategy for neuromuscular blockade remains undefined even in the setting of strong recommendations for quantitative neuromuscular monitoring by several national and international anesthesiology societies. We evaluated a protocol for managing rocuronium blockade and reversal, using quantitative monitoring to guide choice of reversal agent and to confirm full reversal before extubation. METHODS: We conducted a prospective cohort study and enrolled 200 patients scheduled for elective surgery involving the intraoperative use of rocuronium. Providers were asked to adhere to a protocol that was similar to local practice recommendations for neuromusculalr block reversal that had been used for >2 years; the protocol added quantitative monitoring that had not previously been routinely used at our institution. In this study, providers used electromyography-based quantitative monitoring. Pharmacological reversal was accomplished with neostigmine if the train-of-four (TOF) ratio was 0.40 to 0.89 and with sugammadex for deeper levels of blockade. The primary end point was the incidence of postoperative residual neuromuscular blockade (PRNB), defined as TOF ratio <0.9 at time of extubation. We further evaluated the difference in pharmacy costs had all patients been treated with sugammadex. RESULTS: A total of 189 patients completed the study: 66 patients (35%) were reversed with neostigmine, 90 patients (48%) with sugammadex, and 33 (17%) patients recovered spontaneously without pharmacological reversal. The overall incidence of residual paralysis was 0% (95% CI, 0-1.9). The total acquisition cost for all reversal drugs was United States dollar (USD) 11,358 (USD 60 per patient) while the cost would have been USD 19,312 (USD 103 per patient, 70% higher) if sugammadex had been used in all patients. CONCLUSIONS: A protocol that includes quantitative monitoring to guide reversal with neostigmine or sugammadex and to confirm TOF ratio ≥0.9 before extubation resulted in the complete prevention of PRNB. With current pricing of drugs, the selective use of sugammadex reduced the total cost of reversal drugs compared to the projected cost associated with routine use of sugammadex for all patients.

Comparison of train-of-four count by anesthesia providers versus TOF-Watch® SX: a prospective cohort study.

PURPOSE: Qualitative monitoring of neuromuscular blockade using the train-of-four (TOF) count is widely used to determine the timing and dose of reversal agents for neuromuscular blockade. We compared TOF count measured manually by anesthesia providers with that determined by TOF-Watch® SX. METHODS: This prospective observational cohort study included patients who were American Society of Anesthesiologists physical status III or less and undergoing elective surgery. During recovery from an intubating dose of rocuronium or vecuronium, the TOF count was measured every 15 sec using TOF-Watch SX. Anesthesia providers assessed the TOF count twice at each level of TOF-count, 15 sec after the TOF-Watch SX count increased to the next level and then two to five minutes later. RESULTS: In 75 patients, 687 observations were collected. There was agreement between the TOF-Watch SX and the subjective assessment by the provider in 386 (56%) of these observations. The agreement was 87% at TOF counts of 0 and 4. In the 409 observations at TOF counts 1, 2, and 3, the agreement was 36%. Among the 264 observations with disagreement at these TOF counts, providers assessed a higher TOF count in 254 (96%) observations and a lower count in 10 (4%) observations compared with the TOF-Watch SX. CONCLUSION: Anesthesia providers report higher values of TOF count compared with the TOF-Watch SX, especially at intermediate levels of neuromuscular blockade. Since the dosing guidelines for the timing and dose of reversal agents are based on the TOF count derived from the TOF-Watch SX, a manually assessed TOF count may lead to inadequate dosing and/or premature administration of reversal agents.

Ventilation by mask before and after the administration of neuromuscular blockade: a pragmatic non-inferiority trial.

BACKGROUND: Test ventilating prior to administration of neuromuscular blockade (NMB) in order to avoid a cannot intubate-cannot ventilate situation is a classic anesthesia teaching. The primary aim of our study was to show that facemask ventilation (FMV) after NMB was not inferior to FMV prior to NMB with respect to exhaled gas volumes before and after their administration. METHODS: This study was approved by the University of Washington Human Subjects Division (Seattle, Washington, USA). Written informed consent was obtained from all patients. Measurements of tidal volume (Vte) as well as other respiratory parameters during FMV were made for 60 s after induction of anesthesia and again after NMB. Difficult, impossible, inadequate, and dead-space only mask ventilation was graded using published definitions. Difficult intubation was defined as >2 attempts at intubation. The primary outcome was non-inferiority in Vte during both study periods defined as a mean difference of <50 mL. Multivariate analysis was performed to assess for interaction between operator experience, patient risk factors for difficult mask ventilation, exhaled volumes, and use of airway adjuncts. RESULTS: Two-hundred and ten patients were studied. Overall, FMV improved after NMBD. The mean (SD) Vte in mL/breath increased from 399 (169) to 428 (166) (mean dif. 30 mL, p = 0.001) and the minute ventilation in L/min from 5.6 (2.5) to 6.3 (2.5) (mean dif. 0.6, p < 0.001). No patient who was difficult to ventilate after induction became impossible after NMB. DISCUSSION: In patients at risk for or judged to be a difficult FMV by clinical grading scales, tidal volumes improved after administration of NMBDs. None of these patients exhibited a decline in ventilation or became impossible to ventilate after NMBDs. Several limitations are noted, including the use of hand-delivered breaths and inability to account for time-related changes in ventilation conditions independent of NMBDs. CONCLUSION: We conclude that FMV is no worse after NMB than before and is likely to improve airway conditions. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02237443 . Registered August 28, 2014.

Patterns of preoperative consultation and surgical specialty in an integrated healthcare system.

BACKGROUND: Many patients scheduled for elective surgery are referred for a preoperative medical consultation. Only limited data are available on factors associated with preoperative consultations. The authors hypothesized that surgical specialty contributes to variation in referrals for preoperative consultations. METHODS: This is a cohort study using data from Group Health Cooperative, an integrated healthcare system. The authors included 13,673 patients undergoing a variety of common procedures-primarily low-risk surgeries-representing six surgical specialties, in 2005-2006. The authors identified consultations by family physicians, general internists, pulmonologists, or cardiologists in the 42 days preceding surgery. Multivariable logistic regression was used to estimate the association between surgical specialty and consultation, adjusting for potential confounders including the revised cardiac risk index, age, gender, Deyo comorbidity index, number of prescription medications, and 11 medication classes. RESULTS: The authors found that 3,063 (22%) of all patients had preoperative consultations, with significant variation by surgical specialty. Patients having ophthalmologic, orthopedic, or urologic surgery were more likely to have consultations compared with those having general surgery-adjusted odds ratios (95% CI) of 3.8 (3.3-4.2), 1.5 (1.3-1.7), and 2.3 (1.8-2.8), respectively. Preoperative consultations were more common in patients with lower revised cardiac risk scores. CONCLUSION: There is substantial practice variation among surgical specialties with regard to the use of preoperative consultations in this integrated healthcare system. Given the large number of consultations provided for patients with low cardiac risk and for patients presenting for low-risk surgeries, their indications, the financial burden, and cost-effectiveness of consultations deserve further study.

Intraoperative neuromuscular monitoring site and residual paralysis.

BACKGROUND: Residual paralysis is common after general anesthesia involving administration of neuromuscular blocking drugs (NMBDs). Management of NMBDs and reversal is frequently guided by train-of-four (TOF) monitoring. We hypothesized that monitoring of eye muscles is associated with more frequent residual paralysis than monitoring at the adductor pollicis. METHODS: This prospective cohort study enrolled 180 patients scheduled for elective surgery with anticipated use of NMBDs. Collected variables included monitoring site, age, gender, weight, body mass index, American Society of Anesthesiologists physical status class, type and duration of surgery, type of NMBDs, last and total dose administered, TOF count at time of reversal, dose of neostigmine, and time interval between last dose of NMBDs to quantitative measurement. Upon postanesthesia care unit admission, we measured TOF ratios by acceleromyography at the adductor pollicis. Residual paralysis was defined as a TOF ratio less than 90%. Multivariable logistic regression was used to account for unbalances between the two groups and to adjust for covariates. RESULTS: 150 patients received NMBDs and were included in the analysis. Patients with intraoperative TOF monitoring of eye muscles had significantly greater incidence of residual paralysis than patients monitored at the adductor pollicis (P < 0.01). Residual paralysis was observed in 51/99 (52%) and 11/51 (22%) of patients, respectively. The crude odds ratio was 3.9 (95% CI: 1.8-8.4), and the adjusted odds ratio was 5.5 (95% CI: 2.1-14.5). CONCLUSIONS: Patients having qualitative TOF monitoring of eye muscles had a greater than 5-fold higher risk of postoperative residual paralysis than those monitored at the adductor pollicis.

Neuromuscular Blockade Monitoring.

Neuromuscular monitoring is essential for optimal management of neuromuscular blocking drugs. Postoperative residual neuromuscular blockade continues to occur with an unacceptably high incidence and is associated with adverse patient outcomes. Use of a peripheral nerve stimulator and subjective tactile or visual assessment is useful for intraoperative management of neuromuscular blockade, especially when the patient's hand is accessible. Quantitative monitoring is necessary for confirmation of adequate reversal and for identification of patients who have recovered spontaneously and therefore should not receive pharmacologic reversal agents. Guidelines, as well as more user-friendly monitoring equipment, have created momentum toward improving routine perioperative neuromuscular monitoring.

Surgical specialty and preoperative medical consultation based on commercial health insurance claims.

BACKGROUND: Surgical patients are sometimes referred for preoperative evaluations by consultants in other medical specialties, although consultations are unnecessary for many patients, particularly for healthy patients undergoing low-risk surgeries. Surgical specialty has been shown to predict usage of preoperative consultations. However, evidence is generally limited regarding factors associated with preoperative consultations. This study evaluates surgical specialty and other predictors of preoperative consultations. METHODS: This retrospective cohort study analyzed surgery claims of 7400 privately insured patients in Washington, United States, from eight surgical specialties. We estimated log-Poisson generalized estimating equation models that regress whether a patient received a consultation on surgical specialty and covariates accounting for the data's hierarchical structure with patients nesting within surgeons, and surgeons nesting within provider organizations. Covariates include age, gender, Deyo comorbidity index, surgical risk, and geographic factors. RESULTS: Overall, 485 (6.6%) patients had a preoperative consultation. The incidence of preoperative consultation varied significantly by surgical specialty. Orthopedics, neurosurgery, and ophthalmology had 3.9 (95% CI 2.4, 6.5), 2.3 (95% CI 1.1, 4.5), and 2.3 (95% CI 1.1, 4.6) times greater adjusted likelihoods of preoperative consultation than general surgery, respectively. The adjusted likelihoods of consultation for gynecology, urology, otolaryngology, and vascular surgery were not statistically different from general surgery. The following covariates were associated with greater likelihood of preoperative consultation: greater age, higher surgical risk, having one or more comorbidities vs. none, and small rural towns vs. urban areas. More than 75% of all consultations were provided to patients with a Deyo comorbidity index of 0 or 1. Low surgical risk patients had 0.3 (95% CI 0.3, 0.5) times the likelihood of preoperative consultation of intermediate and high-risk patients overall. CONCLUSIONS: The likelihood of preoperative consultation varied fourfold (an absolute 9% points) across surgical specialties. Most consultations were provided to patients with low comorbidity and with low or intermediate surgical risk. To improve usage of preoperative consultations as an evidence-based practice, future research should determine how the health outcomes effects of preoperative consultations vary depending on comorbidity burden and surgical risk.

Qualitative Neuromuscular Monitoring: How to Optimize the Use of a Peripheral Nerve Stimulator to Reduce the Risk of Residual Neuromuscular Blockade.

This review provides recommendations for anesthesia providers who may not yet have quantitative monitoring and sugammadex available and thus are providing care within the limitations of a conventional peripheral nerve stimulator (PNS) and neostigmine. In order to achieve best results, the provider needs to understand the limitations of the PNS. The PNS should be applied properly and early. All overdosing of neuromuscular blocking drugs should be avoided and the intraoperative neuromuscular blockade should be maintained only as deep as necessary. The adductor pollicis is the gold standard site and must be used for the pre-reversal assessment, also when the ulnar nerve and thumb were not accessible intraoperatively. Spontaneous recovery should be maximized and neostigmine should be administered after a TOF count of 4 has been confirmed at the adductor pollicis. Extubation should not occur within 10 min after administration of an appropriate dose of neostigmine.

Preoperative Consultations.

Preoperative consultation is an important intervention that likely has most benefits for intermediate-risk to high-risk patients undergoing major surgery. Consultation rates are likely increasing and there is significant practice variation in the use of consultation. Consultations should be available within a well-organized and coordinated process of preoperative assessment. Preoperative consults should be accessible to anesthesia and surgical teams involved in the procedure and to the providers involved in postoperative care. The role of preoperative consultation should evolve as a rational approach and emerge as a value-based service. New payment methodologies are likely to facilitate appropriate use of this important resource.

Preoperative consultations for medicare patients undergoing cataract surgery.

IMPORTANCE: Low-risk elective surgical procedures are common, but there are no clear guidelines for when preoperative consultations are required. Such consultations may therefore represent a substantial discretionary service. OBJECTIVE: To assess temporal trends, explanatory factors, and geographic variation for preoperative consultation in Medicare beneficiaries undergoing cataract surgery, a common low-risk elective procedure. DESIGN, SETTING, AND PARTICIPANTS: Cohort study using a 5% national random sample of Medicare part B claims data including a cohort of 556,637 patients 66 years or older who underwent cataract surgery from 1995 to 2006. Temporal trends in consultations were evaluated within this entire cohort, whereas explanatory factors and geographic variation were evaluated within the 89,817 individuals who underwent surgery from 2005 to 2006. MAIN OUTCOMES AND MEASURES: Separately billed preoperative consultations (performed by family practitioners, general internists, pulmonologists, endocrinologists, cardiologists, nurse practitioners, or anesthesiologists) within 42 days before index surgery. RESULTS: The frequency of preoperative consultations increased from 11.3% in 1998 to 18.4% in 2006. Among individuals who underwent surgery in 2005 to 2006, hierarchical logistic regression modeling found several factors to be associated with preoperative consultation, including increased age (75-84 years vs 66-74 years: adjusted odds ratio [AOR], 1.09 [95% CI, 1.04-1.13]), race (African American race vs other: AOR, 0.71 [95% CI, 0.65-0.78]), urban residence (urban residence vs isolated rural town: AOR, 1.64 [95% CI, 1.49-1.81]), facility type (outpatient hospital vs ambulatory surgical facility: AOR, 1.10 [95% CI, 1.05-1.15]), anesthesia provider (anesthesiologist vs non-medically directed nurse anesthetist: AOR, 1.16 [95% CI, 1.10-1.24), and geographic region (Northeast vs South: AOR, 3.09 [95% CI, 2.33-4.10]). The burden of comorbidity was associated with consultation, but the effect size was small (<10%). Variation in frequency of consultation across hospital referral regions was substantial (median [range], 12% [0-69%]), even after accounting for differences in patient-level, anesthesia provider-level, and facility-level characteristics. CONCLUSIONS AND RELEVANCE: Between 1995 and 2006, the frequency of preoperative consultation for cataract surgery increased substantially. Referrals for consultation seem to be primarily driven by nonmedical factors, with substantial geographic variation.