Post-tetanic Count Research Articles

Evaluation of Surgical Conditions During Laparoscopic Surgery in Patients With Moderate vs Deep Neuromuscular Block

Abstract Background The routine use of neuromuscular blocking agents reduces the occurrence of unacceptable surgical conditions. In some surgeries, such as retroperitoneal laparoscopies, deep neuromuscular block (NMB) may further improve surgical conditions compared with moderate NMB. In this study, the effect of deep NMB on surgical conditions was assessed. Methods Twenty-four patients undergoing elective laparoscopic surgery for prostatectomy or nephrectomy were randomized to receive moderate NMB (train-of-four 1–2) using the combination of atracurium/mivacurium, or deep NMB (post-tetanic count 1–2) using high-dose rocuronium. After surgery, NMB was antagonized with neostigmine (moderate NMB), or sugammadex (deep NMB). During all surgeries, one surgeon scored the quality of surgical conditions using a five-point surgical rating scale (SRS) ranging from 1 (extremely poor conditions) to 5 (optimal conditions). Video images were obtained and 12 anaesthetists rated a random selection of images. Results Mean (standard deviation) SRS was 4.0 (0.4) during moderate and 4.7 (0.4) during deep NMB (P Conclusions Application of the five-point SRS showed that deep NMB results in an improved quality of surgical conditions compared with moderate block in retroperitoneal laparoscopies, without compromise to the patients’ peri- and postoperative cardiorespiratory conditions. Trial registration The study was registered at clinicaltrials.gov under number NCT01361149.

Efficacy of Sugammadex for the Reversal of Moderate and Deep Rocuronium-induced Neuromuscular Block in Patients Pretreated with Intravenous Magnesium

Magnesium enhances the effect of rocuronium. Sugammadex reverses rocuronium-induced neuromuscular block. The authors investigated whether magnesium decreased the efficacy of sugammadex for the reversal of rocuronium-induced neuromuscular block. Thirty-two male patients were randomized in a double-blinded manner to receive magnesium sulfate (MgSO4) 60 mg/kg or placebo intravenously before induction of anesthesia with propofol, sufentanil, and rocuronium 0.6 mg/kg. Neuromuscular transmission was monitored using TOF-Watch SX acceleromyography (Organon Ltd., Dublin, Ireland). In 16 patients, sugammadex 2 mg/kg was administered intravenously at reappearance of the second twitch of the train-of-four (moderate block). In 16 further patients, sugammadex 4 mg/kg was administered intravenously at posttetanic count 1 to 2 (deep block). Primary endpoint was recovery time from injection of sugammadex to normalized train-of-four ratio 0.9. Secondary endpoint was recovery time to final T1. Average time for reversal of moderate block was 1.69 min (SD, 0.81) in patients pretreated with MgSO4 and 1.76 min (1.13) in those pretreated with placebo (P = 0.897). Average time for reversal of deep block was 1.77 min (0.83) in patients pretreated with MgSO4 and 1.98 min (0.58) in those pretreated with placebo (P = 0.572). Times to final T1 were longer compared with times to normalized train-of-four ratio 0.9, without any difference between patients pretreated with MgSO4 or placebo. Pretreatment with a single intravenous dose of MgSO4 60 mg/kg does not decrease the efficacy of recommended doses of sugammadex for the reversal of a moderate and deep neuromuscular block induced by an intubation dose of rocuronium.

Evaluation of surgical conditions during laparoscopic surgery in patients with moderate vs deep neuromuscular block

BackgroundThe routine use of neuromuscular blocking agents reduces the occurrence of unacceptable surgical conditions. In some surgeries, such as retroperitoneal laparoscopies, deep neuromuscular block (NMB) may further improve surgical conditions compared with moderate NMB. In this study, the effect of deep NMB on surgical conditions was assessed. MethodsTwenty-four patients undergoing elective laparoscopic surgery for prostatectomy or nephrectomy were randomized to receive moderate NMB (train-of-four 1–2) using the combination of atracurium/mivacurium, or deep NMB (post-tetanic count 1–2) using high-dose rocuronium. After surgery, NMB was antagonized with neostigmine (moderate NMB), or sugammadex (deep NMB). During all surgeries, one surgeon scored the quality of surgical conditions using a five-point surgical rating scale (SRS) ranging from 1 (extremely poor conditions) to 5 (optimal conditions). Video images were obtained and 12 anaesthetists rated a random selection of images. ResultsMean (standard deviation) SRS was 4.0 (0.4) during moderate and 4.7 (0.4) during deep NMB (P<0.001). Moderate block resulted in 18% of scores at the low end of the scale (Scores 1–3); deep block resulted in 99% of scores at the high end of the scale (Scores 4 and 5). Cardiorespiratory conditions were similar during and after surgery in both groups. Between anaesthetists and surgeon, there was poor agreement between scores of individual images (average κ statistic 0.05). ConclusionsApplication of the five-point SRS showed that deep NMB results in an improved quality of surgical conditions compared with moderate block in retroperitoneal laparoscopies, without compromise to the patients’ peri- and postoperative cardiorespiratory conditions. Trial registrationThe study was registered at clinicaltrials.gov under number NCT01361149.

Effect of pneumoperitoneum on the recovery from intense neuromuscular blockade by rocuronium in healthy patients undergoing laparoscopic surgery.

BackgroundThis study investigated the effect of pneumoperitoneum on the recovery from intense neuromuscular blockade by rocuronium in healthy patients undergoing laparoscopic abdominal surgery.MethodsThirty adult patients undergoing laparoscopic abdominal surgery were studied. Anesthesia was induced with 1.5 mg/kg of propofol, 12 ug/kg of alfentanil and 0.6 mg/kg of rocuronium and maintained with 2 vol% of sevoflurane and 0.05-0.2 µg/kg/min remifentanil. The neuromuscular relaxation was monitored by Train-of-Four (TOF) and post-tetanic count (PTC). Additional rocuronium of 0.2 mg/kg was administered for deep neuromuscular blockade at 30 min after pneumoperitoneum. Before (PPpre) and 30 min after pneumoperitoneum (PPpost), PTC was measured at 6 min intervals. The relationship between PTC and the time interval to reappearance of T1 response was observed.ResultsThe mean ± SD of the intervals between the detection of 4 counts of the PTC and the first response to TOF stimulation was 13.0 ± 1.1 min and 16.4 ± 6.3 min PPpre and PPpost, respectively (P = 0.20). There were significant negative relationships between PTC observed and the time interval to reappearance of T1 response (adjusted R2 = 0.869, P < 0.001 for PPpre data, and adjusted R2 = 0.561, P < 0.001 for PPpost data). Comparing the difference of regression equation between PPpre and PPpost data using a parallelism test, there was no statistically significant difference (P = 0.193).ConclusionsThis study showed that PP with intra-abdominal pressure at the level of 13-14 mmHg did not affect the recovery from intense neuromuscular blockade by rocuronium in healthy patients undergoing laparoscopic abdominal surgery.

Sugammadex 4.0 mg kg–1 Reversal of Deep Rocuronium-Induced Neuromuscular Blockade: A Multicenter Study in Chinese and Caucasian Patients

Objective: Maintenance of deep Neuro Muscular Blockade (NMB) until the end of surgery may be beneficial in some surgical procedures. The selective relaxant binding agent sugammadex rapidly reverses deep levels of rocuronium-induced NMB. The purpose of this study was to evaluate the efficacy and safety of sugammadex 4.0 mg kg–1 for reversal of deep rocuronium-induced NMB in Chinese and Caucasian patients. Methods: This was an open-label, multicenter, prospective Phase III efficacy study in adult American Society of Anesthesiologists Class 1-3 patients scheduled for surgery under general anesthesia and requiring deep NMB. All patients received intravenous propofol and opioids for induction and maintenance of anesthesia, and a single intubation dose of rocuronium 0.6 mg/kg, with maintenance doses of 0.1-0.2 mg/kg as required. Sugammadex 4.0 mg/kg was administered after the last dose of rocuronium, at a target blockade depth of 1-2 post-tetanic counts. The primary efficacy endpoint was time from sugammadex administration to recovery of the train-of-four (TOF) ratio to 0.9. Safety was also evaluated. Results: Overall, 115 Chinese and 36 Caucasian patients were treated. Geometric mean (95% confidence interval) times to recovery of the TOF ratio to 0.9 were 2.3 (2.1 to 2.6) minutes and 1.4 (1.3 to 1.6) minutes in Chinese and Caucasian patients, respectively. Adverse events were reported in 57% of Chinese patients and 64% of Caucasian patients. Conclusion: This study demonstrates that sugammadex 4.0 mg kg–1 provides effective and rapid reversal of deep rocuronium-induced NMB in Chinese and Caucasian patients. Efficacy equivalence between the two populations cannot be claimed.

Prediction of Optimal Reversal Dose of Sugammadex after Rocuronium Administration in Adult Surgical Patients

The objective of this study was to determine the point after sugammadex administration at which sufficient or insufficient dose could be determined, using first twitch height of train-of-four (T1 height) or train-of-four ratio (TOFR) as indicators. Groups A and B received 1 mg/kg and 0.5 mg/kg of sugammadex, respectively, as a first dose when the second twitch reappeared in train-of-four stimulation, and Groups C and D received 1 mg/kg and 0.5 mg/kg of sugammadex, respectively, as the first dose at posttetanic counts 1–3. Five minutes after the first dose, an additional 1 mg/kg of sugammadex was administered and changes in T1 height and TOFR were observed. Patients were divided into a recovered group and a partly recovered group, based on percentage changes in T1 height after additional dosing. T1 height and TOFR during the 5 min after first dose were then compared. In the recovered group, TOFR exceeded 90% in all patients at 3 min after sugammadex administration. In the partly recovered group, none of the patients had a TOFR above 90% at 3 min after sugammadex administration. An additional dose of sugammadex can be considered unnecessary if the train-of-four ratio is ≥90% at 3 min after sugammadex administration. This trial is registered with UMIN000007245.

Monitoring of intense neuromuscular blockade in a pig model

Intense neuromuscular blockade (NMB) measured by post tetanic count (PTC) was monitored, reversed and verified in this pig model. In a cross-over assessor blinded design six pigs were randomized to either no NMB followed by intense NMB, or intense NMB followed by no NMB. Neuromuscular measurements were performed with acceleromyography [train-of-four (TOF) Watch SX]. In all pigs, the response to TOF nerve stimulation was stable and intense NMB (PTC 0-1) was established with rocuronium 3mg/kg. For reversal, the pigs received sugammadex 20-35mg/kg and returned to TOF-ratio above 0.90 within 2.15min after injection. We established a pig model for monitoring intense NMB with surface stimulation electrodes and acceleromyography. We verified total relaxation of the diaphragm and the abdominal muscles at the PTC 0-1 by suction test and with surface electromyography. This pig model is suitable for studies with experimental abdominal surgery with monitoring of intense NMB, and where relaxation of the diaphragm and the abdominal muscles are required.

Neuromuskuläres Monitoring

The effect of muscle relaxants varies among people and the extent, the duration and recovery from the neuromuscular block varies. Clinical tests cannot determine the effect of muscle relaxants which is only possible with neuromuscular monitoring. The relaxometry procedure measures the muscular response to electrical stimulation of the corresponding motor nerve and the adductor pollicis muscle is mostly used; however, this muscle is not representative for other muscle groups, such as the muscles of the larynx and diaphragm. The muscles of the larynx and diaphragm are more resistant against nondepolarizing muscle relaxants than the adductor pollicis muscle. The train of four (TOF) is used at the beginning of surgery for monitoring of the optimal time for tracheal intubation; moreover, the TOF is used during surgery for monitoring of the muscle blockade and at the end of surgery for monitoring recovery. Monitoring of deep muscular blockades, however, is only possible with the posttetanic count (PTC) when there are no TOF counts. The PTC allows repetition and higher doses of muscle relaxants during abdominal surgery; therefore, conditions for surgery are optimal and cumulation of muscle relaxants is avoided.

A temporary decrease in twitch response following reversal of rocuronium-induced neuromuscular block with a small dose of sugammadex in a pediatric patient

We report a temporary decrease in twitch response following reversal of rocuronium-induced neuromuscular block with a small dose of sugammadex in our dose-finding study in pediatric patients. A 19-month-old female infant (9.6 kg, 80 cm) was scheduled for elective cheiloplasty surgery. Anesthesia was induced with nitrous oxide 50 % and sevoflurane 5 % and maintained with air, oxygen, sevoflurane 3 %, and fentanyl (total, 3 μg/kg). Neuromuscular monitoring was performed at the adductor pollicis muscle after induction of anesthesia but before the administration of rocuronium. Total dose of rocuronium during the surgery was 0.9 mg/kg. Neuromuscular block was reversed with 0.5 mg/kg sugammadex when one response was observed with post-tetanic count stimulation. Twitch responses after sugammadex administration showed a temporary decrease after its initial recovery. Maximum decreases in twitch responses were observed 17 min after initial dose of sugammadex. Twitch responses recovered to their control values after additional doses of 3.5 mg/kg sugammadex (4 mg/kg in total). Time from sugammadex administration to maximum decreases in twitch responses is earlier than has been reported in adults (20–70 min). It is demonstrated that following neuromuscular block reversal with insufficient dose of sugammadex, there is a possibility of the recurrence of residual paralysis within less than 20 min in pediatric patients.

Reversal of rocuronium induced neuromuscular block with sugammadex or neostigmine: a large observational study

This 'real-life' study aimed to analyze the time from the start of neostigmine or sugammadex administration to recovery to a train of four ratio (TOFr) of 0.9 in a real-life in patients receiving rocuronium. The secondary aims were to assess the proportion of patients: presenting TOFr < 0.9 after 5, 10, and 20 min from reversal agent administration, receiving opioids for intraoperative analgesia and extubated in the post-anesthesia care unit (PACU). This was a multisite, prospective, nonrandomized, observational real-life study. Reversal agent was administered at either T2 reappearance or at a post-tetanic count of 1 or 2. Drugs dosages were free according to each investigator's usual practice. Three hundred fifty-nine patients were enrolled onto the study. Time from reversal administration to TOFr to 0.9 is significantly faster in the sugammadex group than in the neostigmine group (shallow block: 2.2 vs. 6.9 min, respectively; P < 0.0001; deep block: 2.7 vs. 16.2 min, respectively; P < 0.0001). The number of patients with TOFr < 0.9 at 5, 10, and 20 min post-reversal agent administration was higher in the neostigmine than in the sugammadex group. Just five patients did not receive opioids. All patients were extubated in the operative room except for a single patient in the sugammadex group who was extubated following PACU admission. This real-life study confirms that reversal time is faster in patients receiving sugammadex than in those receiving neostigmine. TOFr < 0.9 20 min after reversal was only present in patients treated with neostigmine.

Overview of the Introduction of Neuromuscular Monitoring to Clinical Anaesthesia

Muscle relaxants were introduced into clinical practice in the early 1940s. From 1949, assessments were being made of the efficacy of various agents in awake volunteers, usually the researchers themselves. From the early to mid 1950s, while interest in using muscle relaxants was keen, concern emerged in the surgical literature that there was a higher mortality rate seen in patients receiving muscle relaxants. In fairness, the major article highlighted lack of randomisation, bias and confounding variables but this was largely regarded as showing a toxicity associated with muscle relaxants. By 1961 the matter had been settled that muscle relaxants were not toxic but required careful management and administration. Perhaps fortuitously, measurement of the degree of muscle relaxation was introduced to clinical practice with the use of nerve stimulation. These were measured responses to single twitch stimulus or tetanic stimulation. In 1970, train-of-four ratio was introduced, then in 1981 post-tetanic count, and in 1989 double burst stimulation. This article reviews the introduction of these techniques.

Post-tetanic burst count and train-of-four during recovery from vecuronium-induced intense neuromuscular block under different types of anaesthesia

Post-tetanic burst count and train-of-four during recovery from vecuronium-induced intense neuromuscular block under different types of anaesthesia

Accelographic and mechanical post-tetanic count and train-of-four ratio assessed at the great toe

Accelographic and mechanical post-tetanic count and train-of-four ratio assessed at the great toe

Sugammadex Dosing in Bariatric Patients

We read with interest the article by Llauradó et al .1focusing on the efficiency of ideal body weight–adjusted sugammadex dosing in patients undergoing bariatric surgery. The authors report a high incidence of slow responders and outliers leading to a potential risk of recurarization; they consider ideal body weight–adjusted dosing of sugammadex as unsafe. However, we feel that a significant lack of clarity in both design and methods makes it difficult to draw any conclusion from that study.First, patients in the deep-block group had a posttetanic count (PTC) ⩽ 2, thus including also those with no response to PTC. According to the good clinical research practice for pharmacodynamic studies of neuromuscular blocking agents, deep block is defined as no response to train-of-four stimulation but at least one response to the 15 PTC stimulations.2This definition is used because PTC1 is the deepest neuromuscular block that can be precisely defined; as soon as no response to PTC is detectable, neuromuscular block can no longer be quantified. Indeed, it may be close to return of the first PTC response, but it may also be much more intense, with no return to the first PTC answer for a long period. This heterogeneous group of neuromuscular blockade with no response to PTC is summarized as intense blockade.2Although the recommended dose of sugammadex to antagonize moderate or deep block is 2 and 4 mg/kg, respectively, only a few studies focused on sugammadex dosing for intense neuromuscular block, i.e. , when no response to PTC can be detected.3,4They proposed a dose between 8 and 16 mg/kg depending on the elapsed time interval between rocuronium injection and start of reversal. In the present study, however, these patients were also treated with 4 mg/kg ideal body weight sugammadex. Thus, independently of whether sugammadex dosing is based on real or ideal body weight, it was significantly underdosed in patients with no response to PTC. This may have contributed to the “outliers” observed by Llauradó et al . Second, all patients in the present study had either a PTC ⩽ 2 or a train-of-four count ≥ 2. Not 1 of the 120 patients included in this observational study has a neuromuscular block level in between, that is, corresponding to 3–15 PTC or a train-of-four count of 1. This is at least surprising and let suppose an active control rather than a real observation. Third, induction of anesthesia was not standardized; some patients received succinylcholine, whereas others did not. This, however, does not facilitate the interpretation of the results. How can the authors exclude that some of the patients in their study were “slow responders” or “outliers” because of impaired plasmacholinesterase activity leading to slow succinylcholine metabolism rather than a delayed response to sugammadex-induced reversal? Fourth, there may be a bias in the patient’s group assignment. According to the authors, the level of neuromuscular block at the end of surgery determined whether the patients were assigned to deep or moderate block group. However, the total dose of rocuronium was identical in both groups, and surgical time was slightly longer in the deep-block group. Thus, despite the same dose of rocuronium and somewhat longer surgical procedure, 43 patients had a profound block, whereas the remaining 77 patients had a shorter duration but only a moderate neuromuscular block. Interindividual variability to neuromuscular blocking agents is large and the group assignment let suppose that patients more “resistant” to rocuronium were assigned to the moderate group, whereas patients more “sensitive” to rocuronium were assigned to the deep group. Finally, if the train-of-four ratio did not reach 0.9 within 2 or 3 min, respectively, a second dose of sugammadex was given. This, however, did not allow to draw any conclusions on either the risk of recurarization or the time course of an ideal body weight–adjusted sugammadex dosing.Denis Schmartz, M.D.,*Philippe Guerci, M.D., Thomas Fuchs-Buder, M.D., Ph.D.*CHU de Nancy, Hôpital Brabois Adultes, Institut Lorrain du Coeur et des Vaisseaux Louis Mathieu, France. d.schmartz@chu-nancy.fr

In Reply

We read with interest the valuable comments of Schmartz et al ., which require some clarifications.Succinylcholine was used in 14 patients (three in deep blockade [DB] and 11 in moderate blockade [MB]). After excluding patients administered succinylcholine, main data, expressed as median (range) and [percentile 10–90] were total dose of rocuronium (mg), 107.5 (70–290) [85.5–148.7] DB versus 100 (50–180) [68–157] MB, P = 0.169; total dose of sugammadex (mg), 250 (120–520) [200–454] DB versus 150 (100–320) [110–273] MB, P < 0.001; dose of sugammadex per real body weight (mg/kg), 2.30 (1.12–4.42) [1.51–3.925] DB versus 1.2272 (0.88–3.37) [1.0224–2.3638] MB, P < 0.001; time to train-of-four ratio of 0.9 s, 168.5 (20–460) [80–338] DB versus 111.5 (28–300) [49.7–213] MB, P < 0.001. In DB, 16 (40%) patients required a second dose of sugammadex and 14 (21%) in MB, P = 0.047. These results are not different from data presented.1Even if some activity of succinylcholine would be present, it was not determining the results of the study.Sugammadex is able to quickly reverse a neuromuscular blockade (by <2 min); increasing the dose does not hasten recovery.2In our protocol, if the train-of-four ratio was less than 0.9, a second dose of sugammadex was administered after 3 min for DB and 2 min for MB. More than 20% and approximately 40% of patients with MB and DB, respectively, required a second dose. Delayed response to sugammadex is pointed out in most of the publications related to sugammadex administration to lean patients. In addition, the combination of underdose and delayed response has been associated with recurarization.3In favor of safety, tracheal extubation has to be performed when the train-of-four ratio 0.9 target is achieved. A delayed response to sugammadex (target not achieved at the expected time) makes tracheal extubation more challenging, especially in the morbid obese, who are at risk of potential airway serious complications; therefore, requiring close surveillance and neuromuscular monitoring.In the first draft to ANESTHESIOLOGY, “Profound Blockade” was defined as “posttetanic count ≥ 1 to T1 appearance,” literal translation of the text in the observational study protocol (approval reference SAB-SUG-2011-01). Reviewers asked for a better description of DB, so we remade figure 1, modifying the definition of DB by using the number of twitches in the posttetanic count (posttetanic count = 0–12 twitches); however, on the draft we send and in the final draft version, “posttetanic count = 0–2 twitches” were written (this error was also reproduced in the text). This has created difficulty in interpreting methods. We apologize for that. Reviewing our database, all patients with DB had almost one twitch at posttetanic response count; therefore, no patient had intense neuromuscular blockade.Even not significant, slightly more rocuronium was administered to patients with DB (even more after excluding patients administered succinylcholine). As it has been indicated, the interindividual variability to neuromuscular blocking agents is large, even more for rocuronium.4This variability could be facilitated by the association with sevoflurane in our patients.When large doses of rocuronium have been used, we do not know how much rocuronium is still available after sugammadex administration. Redistribution of rocuronium might explain delayed response, or even outliers; however, this statement remains to be demonstrated.Antoni Sabate, M.D., Ph.D.,*Sandra Llaurado, M.D.*Reanimation and Pain Clinic, Hospital Universitari de Bellvitge, Universitat de Barcelona Health Campus, Barcelona, Spain. asabatep@bellvitgehospital.cat

Effect of variations in depth of neuromuscular blockade on rating of surgical conditions by surgeon and anesthesiologist in patients undergoing laparoscopic renal or prostatic surgery (BLISS trial): study protocol for a randomized controlled trial

BackgroundSurgical conditions in laparoscopic surgery are largely determined by the depth of neuromuscular relaxation. Especially in procedures that are confined to a narrow working field, such as retroperitoneal laparoscopic surgery, deep neuromuscular relaxation may be beneficial. Until recently, though, deep neuromuscular block (NMB) came at the expense of a variety of issues that conflicted with its use. However, with the introduction of sugammadex, rapid reversal of a deep NMB is feasible. In the current protocol, the association between the depth of NMB and rating of surgical conditions by the surgeon and anesthesiologist is studied.Methods/designThis is a single-center, prospective, randomized, blinded, parallel group and controlled trial. Eligible patients are randomly assigned to one of two groups: (1) deep NMB (post-tetanic count, one or two twitches; n = 12) and (2) moderate NMB (train-of-four, 1 to 2 twitches, n = 12) by administration of high-dose rocuronium in Group 1 and a combination of atracurium and mivacurium in Group 2. The NMB in Group 1 is reversed by 4 mg/kg sugammadex; the NMB in Group 2 by 1 mg neostigmine and 0.5 mg atropine. Patients are eligible if they are over 18 years, willing to sign the informed consent form, and are scheduled to undergo an elective laparoscopic renal procedure or laparoscopic prostatectomy. A single surgeon performs the surgeries and rates the surgical conditions on a five-point surgical rating scale (SRS) ranging from 1 (poor surgical conditions) to 5 (excellent surgical conditions). The intra-abdominal part of the surgeries is captured on video and a group of five anesthesiologists and ten surgical experts will rate the videos using the same SRS. The primary analysis will be an intention-to-treat analysis. Evaluation will include the association between the level of NMB and SRS, as obtained by the surgeon performing the procedure and the agreement between the scoring of the images by anesthesiologists and surgeons.DiscussionWe aim to show that under the right conditions the perceived opposing goals of surgeons and anesthesiologists (optimal surgical conditions vs. optimal postoperative conditions) may be met without compromise to either.Trial registrationClinicalTrials.gov identifier NCT01631149.

Epidural Bupivakainin Propofol, Alfentanil, Veküronyum Dozlarına ve Nöromusküler Blok Üzerine Etkisi: Randomize Prospektif, Tek Kör Klinik Çalışma

Objective: This study was planned to ascertain the effects of epidural bupivacaine on the doses of propofol, alfentanil and vecuronium used for the maintenance for general anesthesia in patients receiving thoracic epidural anesthesia (TEA) combined with total intravenous anesthesia (TIVA) in thoracic surgery. In addition, the impacts of TEA on duration, intensity, reversal and the characteristics of residual block related to vecuronium-induced neuromuscular blockade was investigated. Material and Methods: Thirty patients scheduled for thoracic surgery were randomly assigned into two groups. Group 1 received TIVA combined with TEA, whereas Group 2 obtained TIVA solely. Epidural bupivacaine (0.375%) was given 6 mL/h following 1.5 mL/segment bupivacaine (0.5%) bolus in Group 1. General anesthesia was provided with propofol, alfentanil and vecuronium in both groups. Propofol dose was adjusted to maintain bispectral index (BIS) value between 45 and 60, whereas alfentanil dose was titrated according to the hemodynamic parameters. Following neuromuscular monitoring and stabilization of response to the neuromuscular stimulus, 0.1 mg/kg vecuronium was injected intravenously in 5 seconds. The responses to train of four (TOF) stimulation (TOF1 and TOF2), posttetanic count (PTC), and TOF rate (TOFR) values were recorded. The neuromuscular blockade was reversed after closure of surgical incision and the fourth response to TOF during recovery. The residual block was assessed in surgical intensive care unit for 30 minutes. Results: Alfentanil amount used in the maintenance was significantly less in Group 1 compared to Group 2 (p<0.05), whereas there was no difference between the groups for propofol and vecuronium doses (p>0.05). There was no statistically significant difference between the groups with respect to the onset time of vecuronium, TOF1 time following induction, and duration of the clinical effects of vecuronium used for induction and maintenance (p>0.05). Conclusion: It was demonstrated that epidural bupivacaine decreased the requirement of alfentanil without alterations in propofol and vecuronium doses in patients undergoing thoracic surgery in our study. We also suggest that in the present dose, epidural bupivacaine has no effect on duration, intensity, reversal or the characteristics of residual block related to vecuronium-induced neuromuscular blockade.

The effects of magnesium sulfate on neuromuscular blockade by cisatracurium during induction of anesthesia

During the induction of anesthesia, patients are at risk of aspiration while awaiting full muscle relaxation. Magnesium has been shown to have synergistic effects with neuromuscular blocking drugs. We tested if magnesium, as an adjunct, increases the speed of onset of muscle relaxation, thereby decreasing the risk of aspiration. Eighty-eight American Society of Anesthesiologists (ASA) physical status 1 or 2 patients were randomly assigned to three groups. Group Mg-0 received 100mL of normal saline, whereas groups Mg-25 and Mg-50 received magnesium sulfate at doses of 25 and 50mg/kg, respectively. Anesthesia was induced with thiopental 5mg/kg and cisatracurium 0.15mg/kg. A peripheral nerve stimulator and single-twitch test was performed on the ulnar nerve until the twitch responses to stimulation had disappeared, and the times were recorded. Then the patients were intubated and anesthesia was maintained with 100μg/kg/min of propofol. The intensity of blockade was measured at regular time intervals with the post-tetanic count test. The mean times to muscle relaxation in groups Mg-0, Mg-25, and Mg-50 were 226, 209, and 188s, respectively (P=0.047). The intensity of the block increased with the dose of magnesium, and remained highest in group Mg-50 at all times measured (P<0.05). The speed of onset and the intensity of muscle relaxation increased as higher doses of magnesium were used. The increased speed of onset of muscle relaxation produced by magnesium is not substantial enough to justify its use in combination with cisatracurium in rapid sequence induction.

Improved recovery profiles in sinonasal surgery Sugammadex: Does it have a role?

ObjectiveSinonasal surgery is one of the shared airway surgeries that are not uncommonly complicated intra or postoperatively. The proper anesthetic management of these cases plays a crucial role creating a bloodless field. Sugammadex is a new selective relaxant binding drug as it provides a rapid decrease in free rocuronium in the plasma and at nicotinic receptor that help proper awakening of these patients which is extremely important for minimizing the postoperative respiratory complications. The aim of this study is to compare recovery profile in sinonasal surgery in patients reversed by conventional anticholine esterase (Neostigmine) versus those reversed by Sugammadex.MethodsThis study included 40 patients ASA physical status I and II aged 20–45 years with chronic sinusitis undergoing endoscopic sinus surgery with or without septoplasty, hypotensive anesthesia to maintain MAP (50–60 mm Hg), muscle relaxation throughout the procedure at 1–2 posttetanic count (PTCs) by rocuronium infusion, and anesthetic depth maintained using BIS (50–60). Patients were allocated randomly into two equal groups to receive either Sugammadex 4 mg/kg (group I) or Neostigmine 0.05 mg/kg and atropine 0.02 mg/kg (group II) as a reversal agent, and assessment of postoperative respiratory complications was performed using the Postoperative Respiratory System Evaluation Score (PRSES) at 1st and 5th minutes after extubation.ResultsThe reversal time showed highly significant difference between the two groups. Patients in the Sugammadex group could reach a TOF of 0.9 in a mean time 2.47 (0.51) min versus 24.21 (4.7) min for the Neostigmine group; postoperative respiratory complications, the Sugammadex group and the Neostigmine group did not differ statistically; however, more patients in Neostigmine group showed respiratory complications at 1st and 5th minutes after extubation as shown by PRSES Scoring System.ConclusionThis study showed that the use of Sugammadex in reversing rocuronium induced neuromuscular block in patients undergoing functional endoscopic surgery is superior to Neostigmine. Further studies are required to weigh the cost benefit relationship of the use of Sugammadex in routine clinical practice.

A randomised controlled trial comparing sugammadex and neostigmine at different depths of neuromuscular blockade in patients undergoing laparoscopic surgery*

Deep neuromuscular blockade during certain surgical procedures may improve operating conditions. Sugammadex can be used to reverse deep neuromuscular blockade without waiting for spontaneous recovery. This randomised study compared recovery times from neuromuscular blockade induced by rocuronium 0.6 mg.kg(-1), using sugammadex 4 mg.kg(-1) administered at 1-2 post-tetanic count (deep blockade) or neostigmine 50 μg.kg(-1) (plus atropine 10 μg.kg(-1)) administered at the re-appearance of the second twitch of a train-of-four stimulation (moderate blockade), in patients undergoing laparoscopic surgery. The primary efficacy variable was the time from the start of sugammadex/neostigmine administration to recovery of the train-of-four ratio to 0.9. Patients receiving sugammadex recovered 3.4 times faster than patients receiving neostigmine (geometric mean (95% CI) recovery times of 2.4 (2.1-2.7) and 8.4 (7.2-9.8) min, respectively, p<0.0001). Moreover, 94% (62/66) of sugammadex-treated patients recovered within 5 min, vs 20% (13/65) of neostigmine-treated patients, despite the difference in the depth of neuromuscular blockade at the time of administration of both drugs. The ability to provide deep neuromuscular blockade throughout the procedure but still permit reversal at the end of surgery may enable improved surgical access and an enhanced visual field.