Neuromuscular blocking drugs in pediatric anesthesia

Safety and Efficacy of Sugammadex for Neuromuscular Blockade Reversal

Since its first human use in 2005, the γ-cyclodextrin sugammadex (Org 25969) has had the potential to become the reversal agent of choice, for rocuronium- or vecuronium-induced neuromuscular blockade. Sugammadex binds to the aminosteroid neuromuscular blocker, encapsulating it and extracting it from the neuromuscular junction, effectively ceasing activity and allowing neuromuscular transmission to recover rapidly. Phases I–III and subsequent trials have found sugammadex to be safe and effective in a wide range of doses and for the reversal of a range of depth of muscle relaxation in healthy volunteers and a variety of disease states. Sugammadex use may allow refinement of anesthetic practice and improvement in surgical conditions, through the maintenance of deep neuromuscular blockade right to the end of surgery, with subsequent rapid reversal. Debate remains about the use of sugammadex in the treatment of rocuronium anaphylaxis and airway emergencies. The high price of sugammadex currently prohibits its routine use, but if the price falls, after expiry of its patent, it may become cost-effective as a readily available agent in certain specific clinical situations. Serious adverse reactions have occurred in less than 1% of patients and are most commonly because of hypersensitivity. No deaths have been reported, but caution is advised in neonates, pediatrics, and pregnancy where data are lacking.

Continuous-infusion neuromuscular blocking agents in critically ill neonates and children

Neuromuscular blocking agents (NMBAs) are often administered as a prolonged (> 24 hrs) continuous infusion in infants and children in the intensive care unit for a variety of reasons including facilitation of oxygenation and ventilation. No guidelines on the use of NMBAs in pediatric patients are available yet in the United States; however, pediatric guidelines are available in the United Kingdom. Based on a 2007 U.S. survey, the most commonly used nondepolarizing NMBAs for sustained neuromuscular blockade in critically ill children are pancuronium and vecuronium. Recent national drug shortages involving NMBAs have been reported for atracurium, cisatracurium, pancuronium, rocuronium, and vecuronium. Therefore, to explore alternative options for neuromuscular blockade, we conducted a literature search to identify articles evaluating prolonged use (> 24 hrs) of NMBAs administered by continuous infusion. The search was limited to English-language articles in the MEDLINE (1950-August 2010), EMBASE (1988-August 2010), International Pharmaceutical Abstracts (1970-August 2010), and Cochrane Library (1996-August 2010) databases. Relevant abstracts, reference citations, and manufacturers' product information were also reviewed. A total of 13 reports representing 208 children were included in the analysis. Many of the reports described wide interpatient variability in dosing for the specific NMBAs evaluated. Selection of the most appropriate NMBA should be based on the patient's clinical status, potential adverse effects, and pharmacoeconomics. All patients receiving sustained neuromuscular blockade should be monitored routinely to ensure that dosing is appropriate in order to obtain the desired level of blockade. The goal is to use the lowest dose possible in an effort to limit adverse effects or prolonged blockade.

Neuromuscular block and current treatment strategies for its reversal in children

Even though neuromuscular blocking agents are an essential part of balanced anesthesia and the risks of residual paralysis are well documented, many anesthetists seldomly monitor neuromuscular block. Classical reversal agent neostigmine is unable to antagonise a deep neuromuscular block and is rather slow to antagonise even a moderate block. These caveats may have introduced a practice to use muscle relaxants mainly for an endotracheal intubation. This review presents current views on the effects of muscle relaxants and their reversal agents in pediatric patients. This may help clinicians to reconsider the value of muscle relaxants during anesthesia in children.

Pre-operative irreducible C1-C2 dislocations: intra-operative reduction and posterior fixation. The "always posterior strategy"

BACKGROUND

According to Menezes' algorithm, pre-operative dynamic neuroradiological investigation in C1-C2 dislocations (C1C2D) instability is strongly advocated in order to exclude those patients not eligible for posterior fixation and fusion without previous anterior trans-oral decompression. Anterior irreducible compression due to C1C2D instability, it is said, needs trans-oral anterior decompression. We reviewed our experience in order to refute such a paradigm.

METHODS

The study involves 23 patients who were operated on for cranio-vertebral junction (CVJ) instability; all of them had C1C2D of varying degree on x-ray, computerised tomography (CT) and magnetic resonance (MR) imaging of the CVJ. Pre-operatively, irreducible C1C2D was demonstrated only in 3 patients, (2 with Down's Syndrome, one of them was harbouring os odontoideum, 1 Rheumatoid Arthritis), i.e. 13.04%; the remaining 19 (86.9%) had reducible C1-C2 dislocation. After an unsuccessful traction test conducted in the pre-operative phase under sedation, it was possible to completely reduce the C1C2D (with a combination of axial traction with light extension of the neck on the chest and a light flexion of the head on the neck by using a Mayfield head holder) and proceed to posterior fixation in all the patients under general anaesthesia using a precise "timing sequences fixation technique". Wiring (C0 and C3 were fixed first being stretched up to approximately 10 lbs, then C2 in order to pull up this vertebra last by forcing approximately 8 lbs) or screw fixation methods were used to achieve fusion along with post-operative external orthosis and neuroradiological assessment of the C1C2D. The instrumentation produced a lever and pulley effect which assisted reduction of the dislocation.

FINDINGS

At follow up (range 34-55 months-mean 45.33 months) the clinical picture was improved or stable in all patients.

CONCLUSIONS

Pre-operative irreducibility of the C1C2D should not be an absolute indication for trans-oral decompression. An attempt to reduce the dislocation under general anaesthesia and during posterior fixation should be attempted in Down's syndrome, os odontoideum and rheumatoid arthritis.

Anesthesiological and intensive care considerations in children undergoing extensive cerebral excision procedure for congenital epileptogenic lesions

INTRODUCTION

Epilepsy is a relatively common condition in childhood with a generally favorable prognosis of the affected population. Nevertheless, a significant minority of the treated children do not respond to the medical treatment so that surgical treatment is necessary. While minor surgical procedures have a negligible incidence of mortality, major ones may carry a significant risk of perioperative complications. The leading cause of mortality is represented by hemorrhagic derangements after high intraoperative and postoperative blood loss, mostly in very young patients. Therefore, restoration of euvolemia, detection and correction of related bleeding disorders represent the major concern for pediatric neuroanesthesiologists and intensivists throughout the perioperative period. The present report is focused on the anesthesia and intensive care management of the surgical epileptic patient.

CONCLUSION

Authors recommend that these high-risk procedures should be performed in highly experienced centers where pediatric neurosurgery is performed daily.