Stephan R. Thilen

BACKGROUND: Postoperative residual neuromuscular blockade (PRNB) is defined as an adductor pollicis train-of-four ratio (TOFR) 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.

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.

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. 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. 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. 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.

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.

Patients undergoing elective surgery with anesthesia have preoperative and preanesthesia evaluations performed by their operating surgeon and anesthesia provider, respectively. The routine provision of these services is included in Medicare’s global fees to surgeons and anesthesia providers. A subset of patients also receives a formal preoperative medical consultation that is distinct from the routine preoperative evaluations by surgeons and anesthesia providers. Preoperative medical consultation, which may be billed separately to Medicare, is a common health care service.^1,2 However, for most surgical patients, there is no national guideline specifying criteria for referral for such consultations. Although it is recommended that patients with active cardiac conditions undergo further evaluation,³ it is not clear which considerations should trigger the referral of the much larger number of patients who are at low cardiac risk or scheduled to undergo low-risk surgical procedures. In fact, there is little information on how often preoperative consultation is performed among the vast number of patients who undergo elective low-risk procedures in the United States and how referral for consultation is influenced by characteristics at the level of the individual patient, the institution, and the geographic region.