H.D. de Boer

Train-of-four ratio recovery often precedes twitch recovery when neuromuscular block is reversed by sugammadex

Background: Sugammadex reverses rocuronium‐induced neuromuscular block (NMB). In all published studies investigating sugammadex, the primary outcome parameter was a train‐of‐four (TOF) ratio of 0.9. The recovery time of T1 was not described. This retrospective investigation describes the recovery of T1 vs. TOF ratio after the reversal of NMB with sugammadex.

A new approach to anesthesia management in myasthenia gravis: reversal of neuromuscular blockade by sugammadex

A neuromuscular blocking drug (NMBD) induced neuromuscular blockade (NMB) in patients with myasthenia gravis usually dissipates either spontaneously or by administration of neostigmine. We administered sugammadex to a patient with myasthenia gravis to reverse a rocuronium-induced profound NMB. NMBDs predispose such patients to severe postoperative residual paralysis and respiratory complications. Sugammadex binds steroidal NMBDs and, therefore reverses a rocuronium or vecuronium-induced NMB, without interfering with cholinergic transmission. A rapid and complete recovery from profound NMB was achieved and no adverse events were observed. This case suggests that sugammadex is a safe and effective antagonist of a rocuronium induced NMB blockade in patients with myasthenia gravis.

Pharmacodynamics of rocuronium 0.3 mg kg(-1) in adult patients with and without renal failure.

Background and aim: The neuromuscular effects of a bolus dose of rocuronium 0.6 mg kg−1 under propofol anaesthesia in renal failure patients are prolonged compared to healthy patients. The present study aims to describe the neuromuscular effects of 0.3 mg kg−1 rocuronium under propofol anaesthesia in patients with renal failure and to compare these effects with healthy control patients. Methods: With institutional approval and informed consent, 18 healthy patients and 18 patients with renal failure took part in this prospective open label study. The renal failure patients were undergoing either renal transplantation or insertion of a shunt. Rocuronium 0.3 mg kg−1 was given intravenously after induction of anaesthesia with propofol 1‐2 mg kg−1 and fentanyl 2 μg kg−1. Propofol 6‐12 mg kg−1 h−1 was used for maintenance of anaesthesia. Four acceleromyographic responses of the thumb after supramaximal stimulation of the ulnar nerve using surface electrodes at 2 Hz every 15 s were measured and recorded. The onset time, the time to recovery of the first twitch to 25% recovery and the time to a train‐of‐four ratio of 0.7 were all recorded. Wilcoxon rank sum testing was used to compare the pharmacodynamics and to see if medication, gender or electrolytes influenced the duration of the block. P < 0.05 was significant. Results: No statistical differences were seen in the neuromuscular blocking effects of rocuronium between the two groups but there was a significant difference (P < 0.00001) in the variability of the total duration of the block. Conclusions: Rocuronium 0.3 mg kg−1 is suitable for use in patients with renal failure when endotracheal intubation and neuromuscular block for a short period of time are needed. Tracheal intubation is facilitated within 4 min and the block can be antagonized within 20 min.

In vivo animal studies with sugammadex

A review is presented of animal studies of the selective steroidal neuromuscular blocking drug binding agent sugammadex. These studies demonstrate that sugammadex is faster in onset than the currently used acetylcholinesterase inhibitors, has no muscarinic effects, and is characterised by lack of adverse effects on other organs. These results offer support for the further development of sugammadex for clinical use in humans.

Reversal of rocuronium-induced neuromuscular block by sugammadex in neonates: 10AP1-3

Background and Goal of Study: Rocuronium is a commonly used neuromuscular blocking agent in clinical anaesthesia and it is administered in all age groups, including neonates. Sugammadex is the first selective relaxant binding agent designed to reverse a neuromuscular block induced by either rocuronium or vecuronium. Sugammadex has been investigated in adults and children older than 4 years of age. 1,2 However, there are no data available about the ef ficacy and safety of sugammadex reversal of a rocuronium-induced neuromuscular block in neonates. The goal of the study was to investigate the ef ficacy and safety of the use of sugammadex in neonates. Results and discussion: Twenty three patients were enrolled in the study and these patients were divided into two age groups, 1 day (n=8), mean weight (SD) 2.8 kg (0.1) and 1-7 days (n=15), mean weight (SD) 2.4 kg (0.8) respectively. The neuromuscular characteristics are shown in table 1. At the time of the end of surgery neuromuscular monitoring showed profound neuromuscular block in all patients. Accordingly sugammadex was administered in a dose of 4.0 mg/kg. Reversal of a profound rocuronium-induced neuromuscular block with sugammadex was fast in both age groups. The train-of-four ratio recovered to 0.9 within a few minutes. Residual curarization or re-curarization was not observed. Adverse events and changes in vital signs were not observed af ter sugammadex administration. Table 1. Summary of the total rocuronium dose, time of from the start of the administration of sugammadex (4.0 mg/kg) to recovery of the TOF ratio to 0.9 and the final TOF value by age group.

Anesthetic management in a child with Arnold–Chiari malformation and bilateral vocal cord paralysis

We report a case of a child who was scheduled for an emergency ventriculoperitoneal shunt procedure. The patient had a type II Arnold–Chiari malformation (ACM) and associated hydrocephalus and presented with near complete respiratory obstruction from bilateral abductor vocal cord palsy. Early diagnosis and management of airway abnormalities associated with ACM may be lifesaving. Chiari malformations and anesthesia management are discussed.

Takotsubo cardiomyopathy and anaesthesia: case report and review of the literature.

Takotsubo cardiomyopathy is an acute syndrome characterized by cardiac failure from disturbances in the contractility of the left ventricle. It is presumably caused by sympathetic over stimulation. We describe a case of postoperatively developed Takotsubo cardiomyopathy in a 69-year-old female. The syndrome developed in connection with awareness during complete residual paralysis. The literature on this syndrome is reviewed and implications for anaesthesia described.

Sugammadex and rescue reversal.

Sugammadex has been shown to reverse a deep neuromuscular block and re-establish breathing even when administered after only 3 min following a 1.0–1.2 mg.kg dose of rocuronium [1, 2]. It has been shown, even before sugammadex became available, that spontaneous breathing is resumed at a far earlier point in the recovery than to a train-of-four (TOF) ratio of 0.9 [3–5]. The average time of 2.2 min to a TOF ratio of 0.9 in a manikin, reported recently by Bisschops et al., is therefore much longer than would be required for resumption of spontaneous breathing [6]. Hogg et al. actually reported times of 40 and 48 s for return of diaphragmatic movement and recording of exhaled carbon dioxide in real patients after a 16 mg.kg dose of sugammadex in a simulated cannot intubate, cannot ventilate scenario (CICV) [2]. This was sufficient to allow the oxygen saturation to remain above 88% in all subjects following a three-minute period of 100% oxygen administration immediately before induction of anaesthesia. We were not clear from the article of Bisschops et al. when they decided it was a CICV situation, and why it took an average of 6.7 min to administer sugammadex? Intubation during a rapid sequence induction is usually performed 60 s after the administration of the neuromuscular blocking drug and the next 2 min are more than adequate to determine if it is a difficult intubation and ⁄ or ventilation scenario. This would allow sugammadex to be administered within 3 min of administration of rocuronium, as has been done in the simulated studies by Lee et al. and Hogg et al. [1, 2]. Pre-oxygenation allows for a significant period of time before the onset of desaturation [7, 8]. However, it is not clear if the effects of pre-oxygenation were factored into the study by Bisschops et al. [6]. The place where sugammadex is stored should be widely known, it should ideally be available in all operating theatres and, in particular, where out-of-hours emergency work is carried out. Sugammadex can be made available within a minute in such a setting. The choice of using rocuronium to facilitate intubation in the setting described by Bisschops et al. implies that sugammadex would be used to reverse the block rapidly if intubation and ⁄ or ventilation were to prove difficult. As such, everyone in that setting should have known where sugammadex was stored. It appears that some of the team members whom the investigators had chosen did not know about sugammadex. We consider it unacceptable that some of the team members would need to read the package insert at the time of such an emergency. The study by Bisschops et al., however, highlights an important practical issue about the use of sugammadex in emergency situations, and that is the calculation of the dose. Although it is easy to calculate the dose for reversing shallow or deep blocks during elective situations, it is clear that it can pose problems when trying to do this in an emergency situation. We would like to suggest a simplified dose regimen for using sugammadex, similar to what is done with neostigmine in standard practice. In the UK, it is probably customary to use the whole contents of a 2.5 mg ampoule of neostigmine for reversal of neuromuscular block. We suggest that the dose of sugammadex should be: 1 vial of 200 mg for superficial ⁄ shallow block; 2 vials of 200 mg for deep block; 3 vials of 500 mg for rescue reversal. This would provide an appropriate dose for patients weighing up to 100 kg and would cover a large majority of patients. This dose of sugammadex may be higher than that recommended for patients of low body weight, but there is no issue about the safety of sugammadex in these doses. The dose would have to be increased for heavier patients accordingly.

Priapism following continuous thoracic epidural anaesthesia: emergency or a benign condition?

Priapism is a rare complication of epidural anaesthesia, and the pathophysiology is poorly understood. In general, 95% of all priapism episodes is ischemic because of decreased penile blood flow, and therefore requires immediate treatment. A case is reported of a 45‐year‐old male patient in which a clear relation is demonstrated between continuous thoracic epidural analgesia and priapism after transabdominal nephrectomy. The level of epidural anaesthesia supports the theory that the erection is a consequence of increased penile blood flow, thus a relatively harmless condition. However, confirmation by serial cavernous blood gas analysis or colour duplex ultrasonography is mandatory. Until this hypothesis is confirmed, termination of epidural infusion is advised as a primary treatment.