The effect of suxamethonium on the intragastric pressure in infants and children

Cricoid Pressure Controversies

Since cricoid pressure was introduced into clinical practice, controversial issues have arisen, including necessity, effectiveness in preventing aspiration, quantifying the cricoid force, and its reliability in certain clinical entities and in the presence of gastric tubes. Cricoid pressure–associated complications have also been alleged, such as airway obstruction leading to interference with manual ventilation, laryngeal visualization, tracheal intubation, placement of supraglottic devices, and relaxation of the lower esophageal sphincter. This review synthesizes available information to identify, address, and attempt to resolve the controversies related to cricoid pressure. The effective use of cricoid pressure requires that the applied force is sufficient to occlude the esophageal entrance while avoiding airway-related complications. Most of these complications are caused by excessive or inadequate force or by misapplication of cricoid pressure. Because a simple-to-use and reliable cricoid pressure device is not commercially available, regular training of personnel, using technology-enhanced cricoid pressure simulation, is required. The current status of cricoid pressure and objectives for future cricoid pressure–related research are also discussed.

Precurarisation in infants and children less than three years of age

Sixty patients less than three years of age about to undergo adenoidectomy or endoscopy were divided into three groups of 20 each according to age (0-11 months, 12-23 months, 24-35 months). Before the induction of anaesthesia with thiopentone, either tubocurarine 0.05 mg X kg-1 or normal saline was given at random in a double-blind fashion. Three minutes later, the children received succinylcholine 1.5 or 1.0 mg X kg-1, respectively. Muscle movements were graded according to a four-point scale. Blood was sampled for creatine kinase (CK) activity before anaesthesia and on the following morning. When all age groups were combined, there was a significant reduction of muscle movements in patients who had received tubocurarine pretreatment. Serum CK activity rose significantly when saline pretreatment was used in children over the age of one year but not in the infants, despite the presence of muscle movements following succinylcholine administration.

Enflurane inhibits muscle fasciculations caused by suxamethonium in children

Eighty-three children with a mean age of 2.7 years were anaesthetized with either thiopental 5 mg/kg followed by suxamethonium 1.5 mg/kg i.v. or with enflurane 5 vol% in 70% nitrous oxide in oxygen via a face mask. In the enflurane group, venepuncture was performed when the children were unconscious, 1.8 +/- 0.05 (s.e.) min after the start of anaesthesia. After enflurane, suxamethonium 1, 1.5 or 2 mg/kg was administered i.v. for endotracheal intubation. The incidence and duration of muscle fasciculations after suxamethonium were significantly lower (P less than 0.01) in the enflurane groups than in the thiopental group. The fasciculation index was significantly lower (P less than 0.01) in the enflurane groups than in the thiopental group. In the enflurane groups, intubating conditions were better (P less than 0.05) in the children treated with suxamethonium 2 mg/kg than in those treated with suxamethonium 1 mg/kg.

Succinylcholine, fasciculations and myoglobinaemia

The prophylactic effectiveness of a small "self-taming" dose of succinylcholine (0.1 mg X kg-1), of d-tubocurarine (0.05 mg X kg-1), and of pancuronium (0.02 mg X kg-1) on succinylcholine-induced fasciculations and myoglobinaemia was studied in 64 healthy children (ages two to nine years), anaesthetized with halothane, nitrous oxide and oxygen. Serum myoglobin was analyzed by radioimmunoassay and taken as a tracer of muscle damage. No correlation was found between the serum levels of myoglobin and the incidence of muscle fasciculations. Self-taming with succinylcholine decreased the incidence of fasciculations (p = 0.001) but did not decrease the succinylcholine-induced myoglobinaemia (p = 0.224). D-tubocurarine (0.05 mg X kg-1) and pancuronium (0.02 mg X kg-1) both significantly reduced the myoglobinaemia and the fasciculations produced by succinylcholine. The pancuronium pretreated group presented less variable values of serum myoglobin which, when compared to the control group, had a more significant p value (p less than 0.001) than for d-tubocurarine pretreated group (p = 0.003). Muscle fasciculations and increased myoglobin levels were observed in children less than four years old who received succinylcholine. The prophylaxis of acute rhabdomyolytic renal failure due to succinylcholine (seven cases reported in the medical literature) is considered.

Reduction of gastric acid secretion. The efficacy of pre-anaesthetic oral cimetidine in children

Cimetidine 10 mg/kg orally was given at varying times from 60 to 240 minutes pre-operatively to 100 healthy children between the ages of 6 months and 14 years. Cimetidine proved to be most effective when given between 120 and 180 minutes before the induction of anaesthesia. All patients in this group had a gastric pH of more than 2.5 and the mean volume aspirated was also significantly lower than that in the control group. The average peak blood concentration after 10 mg/kg oral cimetidine in four healthy children was 3.25 micrograms/ml (range 1.20-4.80) and occurred 75 minutes after administration (range 60-120 minutes). In these patients the mean (SD) half-life of cimetidine was 138 (18) minutes. The reduction of gastric juice volume and acidity produced by 10 mg/kg oral cimetidine given 120-180 minutes prior to induction of anaesthesia has important clinical implications.