The use of neuromuscular blocking drugs in adult cardiac surgery: results of a national postal survey

A Retrospective Pilot Comparison Trial Investigating Clinical Outcomes in Cardiac Surgical Patients Who Received Sugammadex Reversal During 2018 to 2021

OBJECTIVES

To compare the number of eligible urgent and elective cardiac surgical patients who could be extubated successfully within 6 hours of surgery and who received sugammadex versus those who did not.

DESIGN

This retrospective pilot study compared outcomes in cardiac surgical patients undergoing cardiopulmonary bypass between 2018 to 2021 who received sugammadex versus those who did not.

SETTING

At a tertiary-care hospital in the Northshore of Chicago.

PARTICIPANTS

A total of 358 elective or urgent cardiac surgical patients who underwent cardiopulmonary bypass (by 1 cardiac surgeon) and were extubated within 24 hours of the end of surgery at Evanston Hospital in Evanston, IL, were included.

INTERVENTIONS

Data were examined in the following 2 groups of patients: those who were administered sugammadex and those who were not.

MEASUREMENTS AND MAIN RESULTS

After performing propensity matching for age, sex, body mass index, kidney or liver disease, the number of preoperative conditions (defined as the sum of the presence of the following medical conditions: diabetes, immunosuppressive disease, on home oxygen, on inhaled bronchodilator, or sleep apnea), number of patients who underwent elective or urgent surgery in each group, surgery time, cardiopulmonary bypass duration, number of intraoperative blood products, use of intraoperative midazolam and propofol, a statistically significant increase in the percentage of patients in the sugammadex group were extubated within 6 hours of the end of surgery versus those who did not receive sugammadex (96.67% v 81.33%, p = 0.0428). In addition, there was a statistically significant reduction in time to extubation (hours) (4.72 ± 2.92) v (3.57± 1.96 p = 0.0098) in the sugammadex group. All other outcomes did not meet statistical significance.

CONCLUSION

This retrospective study suggested that using sugammadex reversal in cardiac surgical patients undergoing cardiopulmonary bypass may result in more patients meeting the Society of Thoracic Surgery benchmark extubation criteria within 6 hours of the end of surgery.

Plasma rocuronium concentration in cell salvage blood following cardiac surgery: a case series

PURPOSE

The aim of the study was to evaluate the plasma rocuronium concentration in autologous blood transfusion obtained from the cell salvage (CS) system following cardiac surgery with cardiopulmonary bypass (CPB).

METHODS

This prospective observational study was conducted in a university teaching hospital from July to November 2020. Patients undergoing general anesthesia for cardiac surgery with CPB were enrolled in the study. After separation from CPB, residual blood remaining in the extracorporeal system was collected as the control sample. The second sample (CS blood) was collected from the autologous blood transfusion obtained after completion of the CS system with Cell Saver® Elite®. Hematocrit values of both samples were also examined.

RESULTS

Ten subjects (aged 57-86 years) were enrolled in this study. Plasma rocuronium concentrations (ng/ml) were significantly lower in the CS blood (94.0 ± 77.5) compared to the control (2950 ± 812.2) (p = 0.002). Hematocrit values (%) were significantly higher in the CS blood (75.2 ± 11.3) compared to the control (40.2 ± 10.2) (p = 0.002).

CONCLUSION

Autologous blood transfusion obtained from CS system following cardiac surgery with CPB, only retained a small amount of plasma rocuronium concentration, therefore, the risk of autologous blood transfusion contributing to clinically relevant residual neuromuscular blockade postoperatively should be considered to be low.

TRIAL REGISTRATION

This trial was registered in the University Hospital Medical Information Network under registration number UMIN000040877 (registration date; June 24, 2020).

Postoperative awake paralysis in the intensive care unit after cardiac surgery due to residual neuromuscular blockade: a case report and prospective observational study

PURPOSE

We report a case of awake paralysis due to residual neuromuscular blockade (NMB) in the intensive care unit (ICU) in a patient following fast-track cardiac surgery. As a result of this case, we performed a prospective quality assurance audit to investigate the incidence of residual paralysis in the ICU in a similar population of cardiac surgery patients.

CLINICAL FEATURES AND AUDIT METHODS

A 73-yr-old woman (69 kg) underwent coronary artery bypass surgery under anesthesia induced with intravenous sufentanil 25 µg, midazolam 5 mg, ketamine 25 mg, and rocuronium 100 mg (followed by two additional 50-mg doses during surgery) and maintained with sevoflurane. Postoperatively in the ICU, the patient was initially sedated with propofol (50 mg·hr(-1)) but failed to awaken 90 min after its cessation. As train-of-four neurostimulation showed residual paralysis, she was re-sedated. Neostigmine 3 mg and glycopyrrolate 0.6 mg were administered, and she was extubated 30 min later. During this episode of residual paralysis, the patient was conscious and reported explicit memory of the events. She was discharged on day 7 without psychological distress related to her postoperative awake paralysis. We subsequently performed a prospective audit in 50 consecutive patients to determine the timing of NMB dosing and to quantify the incidence of residual paralysis after fast-track cardiac surgery.

RESULTS

Of the 50 patients studied, 24 (48%) had received an NMB during the last hour of surgery and 33 (66%) had evidence of residual paralysis during the immediate postoperative period.

CONCLUSION

Postoperative residual paralysis after fast-track cardiac surgery was common in our institution and likely contributed to the reported case of postoperative awake paralysis. We suggest that an NMB not be administered after intubation in fast-track patients. If given, however, it must be well communicated to the ICU team upon ICU admission. We further recommend routine assessment of neuromuscular function before sedation is weaned prior to extubation.

Haemodynamic differences between pancuronium and vecuronium in an experimental pig model

OBJECTIVE

To compare baseline cardiovascular function in anesthetised pigs using either pancuronium or vecuronium as a neuromuscular blocker.

STUDY DESIGN

Retrospective, non-randomized comparison.

ANIMALS

Norwegian Land Race pigs (Sus scrofa domesticus) weighing mean 42 ± SD 3 kg.

METHODS

One hundred and sixteen animals from four different research protocols premedicated with identical doses of ketamine, diazepam, atropine and isoflurane, and anaesthetised with pentobarbital, fentanyl, midazolam and N(2)O were arranged into three uniform groups with respect to neuromuscular blocking agent: pancuronium bolus of 0.063 mg kg(-1) followed by 0.14 mg kg(-1) hour(-1) (n = 54), low-dose vecuronium 0.4 mg kg(-1) /0.2 mg kg(-1) hour(-1) (n = 29) and high-dose vecuronium 0.6 mg kg(-1) /0.3 mg kg(-1) hour(-1) (n = 33).

RESULTS

The majority of cardiovascular parameters demonstrated no significant differences between groups. For heart rate, there was an overall group difference, p = 0.036. Dromotropy was low in the pancuronium group, with an increased normalised PR-interval compared to the high-dose vecuronium group, median 0.200 interquartile range (0.190, 0.215) versus 0.182 (0.166, 0.199), p < 0.05. Left ventricular compliance was increased in pancuronium-treated animals, demonstrated as a reduction in the nonlinear end-diastolic pressure volume relationship β compared to both vecuronium groups, 0.021 (0.016, 0.025) versus 0.031 (0.025, 0.046) and 0.031 (0.022, 0.048), p < 0.05. The linear end-diastolic pressure volume relationship EDPVR(lin) was reduced as well in the pancuronium group, compared to the low-dose vecuronium group, 0.131 (0.116, 0.169) versus 0.181 (0.148, 0.247), p < 0.05.

CONCLUSIONS

There are only minor haemodynamic differences when using pancuronium compared to vecuronium in the fentanyl-pentobarbital-midazolam-N(2)O anesthetised domestic pigs. Furthermore, increasing doses of vecuronium have minimal haemodynamic effects.

CLINICAL RELEVANCE

Experimental studies in pigs using either pancuronium or vecuronium as a neuromuscular blocking agent are comparable with regard to cardiac and haemodynamic performance.

Early Treatment with Intranasal Neostigmine Reduces Mortality in a Mouse Model of Naja naja (Indian Cobra) Envenomation

Objective. Most snakebite deaths occur prior to hospital arrival; yet inexpensive, effective, and easy to administer out-of-hospital treatments do not exist. Acetylcholinesterase inhibitors can be therapeutic in neurotoxic envenomations when administered intravenously, but nasally delivered drugs could facilitate prehospital therapy for these patients. We tested the feasibility of this idea in experimentally envenomed mice. Methods. Mice received intraperitoneal injections of Naja naja venom 2.5 to 10 times the estimated LD50 and then received 5 μL neostigmine (0.5 mg/mL) or 5 μL normal saline by nasal administration. Animals were observed up to 12 hours and survivors were euthanized. Results. 100% of control mice died. Untreated mice injected with 2.5× LD50 Naja naja died at average 193 minutes after injection, while 10 of 15 (67%) of treated mice survived and were behaviorally normal by 6 hours (P < 0.02). In the 5× LD50 group, survival was prolonged from 45 minutes to 196 minutes (P = 0.01) and for 10× LD50 mice, survival increased from 30 to 175 minutes (P < 0.02). Conclusion. This pilot suggests that intranasal drugs can improve survival and is the first direct demonstration that such an approach is plausible, suggesting means by which treatment could be initiated before reaching the hospital. Further investigation of this approach to neurotoxic and other types of envenomation is warranted.

[Moroccan survey about neuromuscular relaxant blocking drugs use and reversal management]

OBJECTIVE

To determine current clinical neuromuscular use in Morocco anesthetic practice.

STUDY DESIGN

Clinical practice survey.

METHODS

Anesthesiologists were invited to answer anonymously to question about neuromuscular blocking agents (NMBA): pharmacology, monitoring and antagonism drug use. Corrected yates test was used to compare qualitative parameters and variance analysis for quantitative parameters. P<0.05 was considered as significant.

RESULTS

We had 171 answers, 54% were paramedics (n=93) and 46% (n=78) were physicians (20% global effective in Morocco). Fifty-five percent were seniors. Vecuronium was the most NMBA used in Morocco for 51% of the anesthesiologists. Mean action time of NMBA was underestimate in more than 60% of the staff questioned specially for seniors (24.6%) than juniors (19.2%). Residual neuromuscular blockade was evaluated only by clinical and spirometric parameters in 72%. TOF monitor was used in 18% more in military hospitals (36%) and insurance clinics (40%) than private hospitals (12.5%). Administration of reversal drugs was systematic in 5.8% of anesthesiologists, frequent for 36.3% and rare for 55%.

CONCLUSIONS

This study show an underestimation of residual neuromuscular blockade, poor neuromuscular monitor use and lack of knowledge of NMBA specially for senior anesthesiologists and in private hospitals. We should elaborate Moroccan guideline for NMBA use and provide formal training programs for our anesthetic staff.

Residual neuromuscular block: lessons unlearned. Part I: definitions, incidence, and adverse physiologic effects of residual neuromuscular block

In this review, we summarize the clinical implications of residual neuromuscular block. Data suggest that residual neuromuscular block is a common complication in the postanesthesia care unit, with approximately 40% of patients exhibiting a train-of-four ratio <0.9. Volunteer studies have demonstrated that small degrees of residual paralysis (train-of-four ratios 0.7-0.9) are associated with impaired pharyngeal function and increased risk of aspiration, weakness of upper airway muscles and airway obstruction, attenuation of the hypoxic ventilatory response (approximately 30%), and unpleasant symptoms of muscle weakness. Clinical studies have also identified adverse postoperative events associated with intraoperative neuromuscular management. Large databased investigations have identified intraoperative use of muscle relaxants and residual neuromuscular block as important risk factors in anesthetic-related morbidity and mortality. Furthermore, observational and randomized clinical trials have demonstrated that incomplete neuromuscular recovery during the early postoperative period may result in acute respiratory events (hypoxemia and airway obstruction), unpleasant symptoms of muscle weakness, longer postanesthesia care unit stays, delays in tracheal extubation, and an increased risk of postoperative pulmonary complications. These recent data suggest that residual neuromuscular block is an important patient safety issue and that neuromuscular management affects postoperative outcomes.

Anesthesia in adult cardiac surgery without maintenance of muscle relaxants: a randomized clinical trial

There may be no need for muscle paralysis during cardiac surgery when adequate anesthesia is provided. We studied intra- and post-operative conditions during cardiac surgery without maintenance muscle relaxant therapy. Eighty adult patients who were candidates for elective coronary artery bypass graft surgery were randomly allocated into two groups. In the noMR or study group (noMR group; n = 40) only an intubation dose of cisatracurium (0.15 mg kg(-1)) was administrated, as opposed to the control group (MR group; n = 40), who had a continuous infusion added to the intubation dose. The anesthesia level was maintained at a Bispectral score of 40-50 using a propofol infusion. A remifentanil infusion was titrated to control patient hemodynamic response. During surgery, any minor (fine body or respiratory muscle movements) or major (coarse body movements or bucking/caught) movements were recorded. Postoperatively, analgesia was provided by remifentanil. The surgical condition was classified into three states: good (no movement), acceptable (minor movements), or poor (major movements). Anesthesia, surgery and postoperative characteristics were compared between the two groups. Statistical analysis was performed in only 78 patients (noMR = 38, MR = 40). The demographic and preoperative characteristics of the two groups were comparable. Intra-operative propofol consumption was the same, but significantly more remifentanil was used in the noMR group (p = 0.001). Post-operative characteristics and complication rates did not differ between the two groups. There were no movements in the MR group patients, while in the noMR group one patient had major movement and three had minor movements. We concluded that omitting maintenance muscle relaxants in adult cardiac surgery or eliminating residual muscle paralysis at the end of the surgery without improving early outcome can increase patient intra-operative movement risk.

Muscle relaxation does not influence venous oxygen saturation during cardiopulmonary bypass

STUDY OBJECTIVE

To examine whether the omission of neuromuscular blocking drugs during cardiopulmonary bypass (CPB) is associated with increased anesthetic requirements, higher frequency of intraoperative movements, and lower venous oxygen saturation (SvO(2)).

DESIGN

Prospective, randomized study.

SETTING

Large community hospital.

PATIENTS

30 ASA physical status III and IV patients scheduled for cardiac surgery.

INTERVENTIONS

Patients were randomized to one of two groups: group 1 (n = 15) received a 3xED(95) bolus dose of cisatracurium at induction and thereafter no more neuromuscular blocking drug; group 2 (n = 15) received a continuous infusion of cisatracurium during the entire procedure.

INTERVENTIONS

Both groups received a standardized anesthetic with bispectral index-guided propofol target-controlled infusion and a remifentanil infusion steered by hemodynamic changes. Venous oxygen saturation was continuously determined during CPB.

MEASUREMENTS AND MAIN RESULTS

Propofol consumption was 5.4 +/- 1.7 and 4.4 +/- 1.0 mg/(kg/h) in groups 1 and 2, respectively (P = 0.07). Remifentanil consumption was 0.15 +/- 0.05 and 0.17 +/- 0.05 mug/(kg/min) in groups 1 and 2, respectively (P = 0.19). In groups 1 and 2, no patient recalled any intraoperative phenomena; none moved or had diaphragmatic contractions. During CPB, SvO(2) was 81.3 +/- 3.2% (76%-85%) in group 1 and 80.6 +/- 3.1% (73%-85%) in group 2 (P = 0.53).

CONCLUSIONS

Omitting the continuous administration of neuromuscular blocking drugs during CPB did not increase anesthetic requirements. No intraoperative movements occurred, nor was there decreased SvO(2).

Prolonged (more than ten hours) neuromuscular blockade after cardiac surgery: report of two cases

PURPOSE

We examine two cases of prolonged neuromuscular blockade (NMB) after cardiac surgery. To the best of our knowledge, these are the first reported cases of complete paralysis lasting more than ten hours after surgery.

CLINICAL FEATURES

We attribute the extended durations of NMB (more than ten hours) to high doses of NMB drugs in combination with magnesium sulphate and moderate renal failure. Advanced age, hepatic disease, aminoglycoside exposure, hypocalcemia, and possible interaction between rocuronium and pancuronium may have played minor roles.

CONCLUSION

We should avoid administering large doses of NMB agents, even in the context of planned postoperative ventilation. If NMB is not monitored intraoperatively in patients who are at risk of prolonged NMB, then train-of-four response should be measured in the intensive care unit. Adequate sedation should be provided until proper recovery of neuromuscular function is documented.