M. R. Gätke

Postoperative muscle paralysis after rocuronium: less residual block when acceleromyography is used

Background: Residual muscle paralysis after anesthesia is common after pancuronium, but less common following the intermediate‐acting drugs vecuronium and atracurium. Therefore, many anesthetists do not monitor neuromuscular function when using an intermediate‐acting agent. The purpose of this prospective, randomised and double‐blind study was to establish the incidence and degree of postoperative residual block following the use of rocuronium in patients not monitored with a nerve stimulator, and to compare it with results obtained in patients monitored using acceleromyography (AMG).

Surgical space conditions during low-pressure laparoscopic cholecystectomy with deep versus moderate neuromuscular blockade: a randomized clinical study.

BACKGROUND:Laparoscopic cholecystectomy performed during low intraabdominal pressure (<12 mm Hg) is associated with significantly less postoperative pain than standard pressure (≥12 mm Hg). The impact on surgical space conditions and safety of operating at lower pressures has not been adequately described, but deep neuromuscular blockade may be beneficial. We investigated if deep muscle relaxation would be associated with a higher proportion of procedures with “optimal” surgical space conditions compared with moderate relaxation during low-pressure (8 mm Hg) laparoscopic cholecystectomy. METHODS:In this assessor-blinded study, 48 patients undergoing elective laparoscopic cholecystectomy were administered rocuronium for neuromuscular blockade and randomized to either deep neuromuscular blockade (rocuronium bolus plus infusion maintaining a posttetanic count 0–1) or moderate neuromuscular blockade (rocuronium repeat bolus only for inadequate surgical conditions with spontaneous recovery of neuromuscular function). Patients received anesthesia with propofol, remifentanil, and rocuronium. The primary outcome was the proportion of procedures with optimal surgical space conditions (assessed by the surgeon as 1 on a 4-point scale). Secondary outcomes included the proportion of procedures completed at pneumoperitoneum 8 mm Hg and surgical space conditions on dissection of the gallbladder (numeric rating scale 0–100; 0 = optimal surgical space conditions; 100 = unacceptable surgical space conditions). RESULTS:Optimal surgical space conditions during the entire procedure were observed in 7 of 25 patients allocated to deep neuromuscular blockade and in 1 of 23 patients allocated to moderate blockade (P = 0.05) with an absolute difference of 24% between the groups (95% confidence interval, 4%–43%). Laparoscopic cholecystectomy was completed at pneumoperitoneum 8 mm Hg in 15 of 25 and 8 of 23 patients in the deep and moderate group, respectively (95% confidence interval, −2% to 53%; P = 0.08). Surgical space conditions during dissection of the gallbladder assessed by use of the numeric rating scale were 20 (10–50) (median [25%–75% range]) in the deep neuromuscular blockade group and 30 (10–50) in the moderate group (P = 0.58; Wilcoxon-Mann-Whitney odds, 1.2; 95% confidence interval, 0.6–2.5). No operations were converted to laparotomy. CONCLUSIONS:Deep neuromuscular blockade was associated with surgical space conditions that were marginally better than with moderate muscle relaxation during low-pressure laparoscopic cholecystectomy.

Neuromuscular blockade for optimising surgical conditions during abdominal and gynaecological surgery: a systematic review

The level of neuromuscular blockade (NMB) that provides optimal surgical conditions during abdominal surgery has not been well established. The aim of this systematic review was to evaluate current evidence on the use of neuromuscular blocking agents in order to optimise surgical conditions during laparoscopic procedures and open abdominal surgery.

Optimising abdominal space with deep neuromuscular blockade in gynaecologic laparoscopy – a randomised, blinded crossover study

Insufflation of the abdomen during laparoscopy improves surgical space, but may cause post‐operative shoulder pain. The incidence of shoulder pain is reduced using a lower insufflation pressure, but this may, however, compromise the surgical space. We aimed at investigating whether deep neuromuscular blockade (NMB) would enlarge surgical space, measured as the distance from the sacral promontory to the trocar in patients undergoing gynaecologic laparoscopy.

Postoperative shoulder pain after laparoscopic hysterectomy with deep neuromuscular blockade and low-pressure pneumoperitoneum: A randomised controlled trial.

BACKGROUND Postoperative shoulder pain remains a significant problem after laparoscopy. Pneumoperitoneum with insufflation of carbon dioxide (CO2) is thought to be the most important cause. Reduction of pneumoperitoneum pressure may, however, compromise surgical visualisation. Recent studies indicate that the use of deep neuromuscular blockade (NMB) improves surgical conditions during a low-pressure pneumoperitoneum (8 mmHg). OBJECTIVE The aim of this study was to investigate whether low-pressure pneumoperitoneum (8 mmHg) and deep NMB (posttetanic count 0 to 1) compared with standard-pressure pneumoperitoneum (12 mmHg) and moderate NMB (single bolus of rocuronium 0.3 mg kg−1 with spontaneous recovery) would reduce the incidence of shoulder pain and improve recovery after laparoscopic hysterectomy. DESIGN A randomised, controlled, double-blinded study. SETTING Private hospital in Denmark. PARTICIPANTS Ninety-nine patients. INTERVENTIONS Randomisation to either deep NMB and 8 mmHg pneumoperitoneum (Group 8-Deep) or moderate NMB and 12 mmHg pneumoperitoneum (Group 12-Mod). Pain was assessed on a visual analogue scale (VAS) for 14 postoperative days. MAIN OUTCOME MEASURES The primary endpoint was the incidence of shoulder pain during 14 postoperative days. Secondary endpoints included area under curve VAS scores for shoulder, abdominal, incisional and overall pain during 4 and 14 postoperative days; opioid consumption; incidence of nausea and vomiting; antiemetic consumption; time to recovery of activities of daily living; length of hospital stay; and duration of surgery. RESULTS Shoulder pain occurred in 14 of 49 patients (28.6%) in Group 8-Deep compared with 30 of 50 (60%) patients in Group 12-Mod. Absolute risk reduction was 0.31 (95% confidence interval 0.12 to 0.48; P = 0.002). There were no differences in any secondary endpoints including area under the curve for VAS scores. CONCLUSION Deep NMB and low-pressure pneumoperitoneum (8 mmHg) reduced the incidence of shoulder pain after laparoscopic hysterectomy in comparison to moderate NMB and standard-pressure pneumoperitoneum (12 mmHg). TRIAL REGISTRATION Clinicaltrials.gov identifier: NCT01722097.

Is deep neuromuscular blockade beneficial in laparoscopic surgery? Yes, probably

Deep neuromuscular blockade during laparoscopic surgery may provide some clinical benefit. We present the ‘Pro‐’ argument in this paired position paper.

Response to succinylcholine in patients carrying the K-variant of the butyrylcholinesterase gene.

BACKGROUND:Succinylcholine is usually metabolized quickly by the butyrylcholinesterase enzyme (BChE) but genetic variants of BChE may prolong the duration of action. The Kalow (K) variant is the most common mutation in the butyrylcholinesterase gene (BCHE), being present in 25% of Caucasians. The significance of the K-variant for the duration of action of succinylcholine has not been well studied. Our hypothesis was that the duration of action of succinylcholine would be prolonged in patients heterozygous for the K-variant genotype compared with the normal genotype (wild-type). METHODS:We included 70 adult surgical patients who received succinylcholine 1 mg/kg for rapid sequence induction. Neuromuscular monitoring was performed using ulnar nerve stimulation and acceleromyography. Duration of action of succinylcholine was defined as the time to 90% recovery of first twitch in train-of-four (T1 90%), BChE activity was determined, and the presence of BCHE K and A (atypical) variants were determined using DNA analysis. RESULTS:The wild-type BCHE was present in 38 patients, and 21 were heterozygous for the K-variant. Mean (SD) T1 90% in patients heterozygous for the K-variant, 11.6 (3.5) minutes, was longer than in patients with the wild-type genotype, 9.5 (2.7) minutes (P = 0.023), with a mean (95% confidence interval) difference of 2.1 (0.3–4.0) minutes. Patients heterozygous for the K-variant had a BChE activity of 5978 U/L compared with 7703 U/L in the wild-type group (P = 0.0045). CONCLUSION:We conclude that the mean duration of action of succinylcholine is prolonged for the patient heterozygous for the K-variant allele by at most 4 minutes relative to the wild-type, but this difference is small relative to the wide variability and overlap in recovery times among all patients.

Tracheal intubation with a flexible fibreoptic scope or the McGrath videolaryngoscope in simulated difficult airway scenarios: a randomised controlled manikin study.

BACKGROUND Flexible fibreoptic endoscopic (FFE) intubation is considered the ‘gold-standard’ when difficult airway management is anticipated. Several videolaryngoscopes have been developed to facilitate intubation by laryngoscopy. OBJECTIVE The aim of the study was to compare the performance of the McGrath series 5 videolaryngoscope (McGrath videolaryngoscope) and the FFE for tracheal intubation in manikins with a simulated difficult airway, hypothesizing that the McGrath videolaryngoscope intubation would prove faster than FFE intubation. DESIGN A randomised controlled study. SETTING The Danish Institute for medical simulation between December 2009 and June 2010. PARTICIPANTS Twenty-eight anaesthesia residents participating in the Danish mandatory 3-day airway management course. INTERVENTIONS All participants received instructions and training in the use of the McGrath videolaryngoscope and FFE. The participants then performed tracheal intubation on a SimMan manikin once with the McGrath videolaryngoscope and once with the FFE in three difficult airway scenarios: (1) pharyngeal obstruction; (2) pharyngeal obstruction and cervical rigidity; (3) tongue oedema. MAIN OUTCOME MEASURES We measured successful intubations, defined as intubation within 120 s, and time to tracheal intubation. RESULTS The trachea was intubated within 120 s with the McGrath videolaryngoscope in 25 out of 27 (93%), 25 out of 28 (89%) and 18 out of 28 (64%) occasions compared with 11 out of 28 (40%), 11 out of 28 (40%) and 16 out of 28 (57%) with the FFE in scenarios (1), (2) and (3), respectively. Time to tracheal intubation was shorter with the McGrath videolaryngoscope in scenarios (1) and (2) than with the FFE (Wilcoxon signed rank sum test, P < 0.0001). CONCLUSION The McGrath videolaryngoscope is a valuable device with higher success rate and a quicker performance in simulated difficult airways. In patients, videolaryngoscopy may have a role in difficult airway algorithms, but the optimal device has yet to be found.

Objective neuromuscular monitoring of neuromuscular blockade in Denmark: an online‐based survey of current practice

Neuromuscular blocking agents are commonly used during general anaesthesia but can lead to postoperative residual neuromuscular blockade and associated morbidity. With appropriate objective neuromuscular monitoring (objNMM) residual blockade can be avoided. In this survey, we investigated the use of objNMM in Denmark.

Validation of subjective rating scales for assessment of surgical workspace during laparoscopy

Recently, studies have focused on how to optimize laparoscopic surgical workspace by changes in intra‐abdominal pressure, level of muscle relaxation or body position, typically evaluated by surgeons using subjective rating scales. We aimed to validate two rating scales by having surgeons assess surgical workspace in video sequences recorded during laparoscopic surgery.