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

Residual neuromuscular blockade in the ICU: a prospective observational study and national survey

Residual neuromuscular blockade is associated with significant morbidity. It has been widely studied in anaesthesia; however, the incidence of residual neuromuscular blockade in patients managed in the ICU is unknown. We conducted a prospective observational study in a tertiary ICU to determine the incidence of residual neuromuscular blockade using quantitative accelerographic monitoring. We tested for residual neuromuscular blockade (defined as a train-of-four ratio < 0.9) before cessation of sedation in anticipation of tracheal extubation. We also surveyed 16 other ICUs in New Zealand to determine their use of neuromuscular monitoring. A total of 191 patients were included in the final analysis. The incidence (95%CI) of residual neuromuscular blockade was 43% (36-50%), with a similar incidence observed in non-postoperative and postoperative patients. There was a lower risk of residual neuromuscular blockade with atracurium than rocuronium (risk ratio (95%CI) of 0.39 (0.12-0.78)) and a higher risk with pancuronium than rocuronium (1.59 (1.06-2.49)). Our survey shows that, in New Zealand ICUs, monitoring of neuromuscular function is rarely carried out before tracheal extubation. When neuromuscular monitoring is undertaken, it is based on individual clinician suspicion and performed using qualitative measurements. No ICU reported using a quantitative monitor or a clinical guideline. The results demonstrate a high incidence of residual neuromuscular blockade in our ICU patients and identify the type of neuromuscular blocking drug as a possible risk factor. Monitoring neuromuscular function before tracheal extubation is not currently the standard of care in New Zealand ICUs. These data suggest that residual neuromuscular blockade may be an under-recognised problem in ICU practice.

A fresh look at paralytics in the critically ill: real promise and real concern

Neuromuscular blocking agents (NMBAs), or “paralytics,” often are deployed in the sickest patients in the intensive care unit (ICU) when usual care fails. Despite the publication of guidelines on the use of NMBAs in the ICU in 2002, clinicians have needed more direction to determine which patients would benefit from NMBAs and which patients would be harmed. Recently, new evidence has shown that paralytics hold more promise when used in carefully selected lung injury patients for brief periods of time. When used in early acute respiratory distress syndrome (ARDS), NMBAs assist to establish a lung protective strategy, which leads to improved oxygenation, decreased pulmonary and systemic inflammation, and potentially improved mortality. It also is increasingly recognized that NMBAs can cause harm, particularly critical illness polyneuromyopathy (CIPM), when used for prolonged periods or in septic shock. In this review, we address several practical considerations for clinicians who use NMBAs in their practice. Ultimately, we conclude that NMBAs should be considered a lung protective adjuvant in early ARDS and that clinicians should consider using an alternative NMBA to the aminosteroids in septic shock with less severe lung injury pending further studies.

[Prolonged residual paralysis after a single intubating dose of rocuronium: an unexpected cause]

Postoperative curarization following a single dose of rocuronium is a known risk quickly diagnosed through the monitoring of neuromuscular blockade. Different etiologies can cause a prolonged block. We report the case of a misdiagnosis of prolonged neuromuscular blockade by a failure in the monitoring system of curarization.

[Extremely prolonged neuromuscular block after a single dose of rocuronium]

Postoperative curarization in patients has been established. Nevertheless, extremely prolonged neuromuscular blockades are rare. We report the case of a prolonged neuromuscular blockade (lasting 10 hours) following a single dose of rocuronium, in an elderly patient with severe renal failure. We have studied the possible causes of prolonged curarization, and discussed the interest of the use of sugammadex in such cases.

Extremely prolonged neuromuscular blockade after rocuronium: a case report

It is known that the duration of rocuronium action can be prolonged in elderly patients and that such action shows important interindividual variability. We report a case of prolonged neuromuscular block lasting 11 h, in a woman subjected to kidney transplantation. The possible causes of such prolonged action, inherent to the drug, or related to external factors, are commented.

Infusions of rocuronium and cisatracurium exert different effects on rat diaphragm function

OBJECTIVE

Aminosteroidal and benzylisoquinoline neuromuscular blocking agents are used in the intensive care unit to facilitate mechanical ventilation. The use of these agents has been associated with development of critical illness myopathy; however, the relative frequency of myopathy development among agents is not known. The aim of our study was to compare the effects of 24 h infusion of rocuronium or cisatracurium on the diaphragm in mechanically ventilated rats.

DESIGN

Randomized, controlled experiment.

SETTING

Basic animal science laboratory.

SUBJECTS

Male Wistar rats, 14 weeks old.

INTERVENTIONS

Rats were divided into four groups to receive either saline, rocuronium (low dose) or cisatracurium (low or high dose).

MEASUREMENTS AND RESULTS

After 24 h, in vitro diaphragm tetanic force was decreased after rocuronium (-33% vs. saline), while the force was more preserved after cisatracurium, even in the high-dose group. Cross-sectional areas of the different diaphragm and gastrocnemius fibers were unaltered. Diaphragmatic MURF-1 mRNA was increased after rocuronium (+44% vs. saline), while unchanged in both cisatracurium groups. Calpain activity was increased after rocuronium (+75% vs. saline) and unchanged in the cisatracurium groups. MURF-1 mRNA expression and calpain activity were negatively correlated with diaphragm force.

CONCLUSIONS

Cisatracurium infusion during controlled mechanical ventilation exerted less detrimental effects on diaphragm function and proteolytic activity than infusion of rocuronium, even with the higher effective dose. These data suggest that increased calpain activity and increased activation of the ubiquitin proteasome system play a role in the different effects of these agents.

Magnesium sulphate as an adjuvant to total intravenous anesthesia in septorhinoplasty: a randomized controlled study

BACKGROUND

The current study was designed to assess the effect of magnesium sulphate infusion on hemodynamic parameters, neuromuscular blocking, propofol consumption, serum concentration of magnesium ions, and recovery from anesthesia during total intravenous anesthesia.

METHODS

For this study, 60 patients undergoing septorhinoplasty operations were randomly allocated to receive magnesium sulphate (group M) or saline (group C) intravenously. The patients in group M received 15% magnesium sulphate 50 mg/kg in 100 ml of saline, and those in group C received an equal volume of saline before induction of anesthesia followed by 8 mg/kg/h infusion of either magnesium sulphate (group M) or an equal volume of saline (group C) until the end of surgery. Anesthesia was induced and maintained with propofol, remifentanil infusions, and vecuronium in both groups.

RESULTS

Propofol requirements were significantly lower in group M than in group C (p < 0.05). The hemodynamic variables were similar in the two groups. The neuromuscular potency of vecuronium was greater in group M than in group C (p < 0.05). The verbal numeric scale values for pain were found to be significantly lower in group M than in group C (p < 0.05). Whereas the serum magnesium was in the normal range at the induction of anesthesia in the both groups, it was significantly lower in group C than in group M postoperatively (p < 0.05).

CONCLUSION

Magnesium sulphate can be used safely as an adjuvant to total intravenous anesthesia for day case surgeries, with the effect from potentialization of neuromuscular blockade taken into consideration.

Influence of acute normovolaemic haemodilution on the dose-response relationship, time-course of action and pharmacokinetics of rocuronium bromide

BACKGROUND

Acute normovolaemic haemodilution (ANH) is an effective strategy for avoiding or reducing allogeneic blood transfusion. We aimed to study its effect on the pharmacological profile of rocuronium.

METHODS

In two study centres, 28 patients undergoing major surgery with ANH were matched with 28 control patients. In the dose-response groups, using the mechanomyograph, neuromuscular block of six consecutive incremental doses of rocuronium 50 microg kg(-1), followed by 300 microg kg(-1), was evaluated. In the pharmacokinetics groups, serial arterial blood samples were withdrawn for rocuronium assay after a single dose of rocuronium 600 microg kg(-1).

RESULTS

ANH resulted in a shift to the left of rocuronium dose-response curve. Rocuronium effective dose(95) (ED(95)) was 26% lower (P<0.05) in the ANH group [283.4 (92.0) microg kg(-1)] compared with the control group [383.5 (127.3) microg kg(-1)]. Times from administration of last incremental dose until 25% of first response of train-of-four (TOF) recovery (Dur(25)) and 0.8 TOF ratio recovery (Dur(0.8)) were 28% longer in the ANH group [39.9 (8.4), 66.7 (14.2) min] compared with the control group [31.1 (6.6), 52.1 (15.8) min] (P<0.01, P<0.05), respectively. Volume of distribution was higher (P<0.01), central clearance was lower (P<0.05) and terminal elimination half-life was longer (P<0.0001) in the ANH group [234.97 (47.11) ml kg(-1), 4.70 (0.94) ml kg(-1) min(-1), 77.29 (12.25) min] compared with the control group [181.22 (35.73) ml kg(-1), 5.71 (1.29) ml kg(-1) min(-1), 56.86 (10.05) min, respectively].

CONCLUSION

ANH resulted in prolongation of rocuronium time-course of action, thus careful monitoring of neuromuscular block is recommended in patients who undergo ANH.