The use of d-tubocurarine in neonatal anaesthesia

Reevaluation and update on efficacy and safety of neostigmine for reversal of neuromuscular blockade

Postoperative residual neuromuscular block is a serious threat which endangers the patient safety. Neostigmine has been the most commonly used anticholinesterase for the pharmacological reversal of neuromuscular blockade. Although newer agents have been introduced recently, neostigmine has some irreplaceable advantages, including broad-spectrum reversal of all nondepolarizing neuromuscular blocking drugs, low cost, and availability of more related data for clinical practice to refer to. Neostigmine is also noticed to have some drawbacks, such as the inability to reverse profound and deep blockade, potential induction of muscle weakness, cardiovascular adverse effects, and so on. Data on the usage of neostigmine in the geriatric and the pediatric population are still insufficient. Some discrepancies are observed in the results from previous studies which need further investigation. However, recent studies offer some renewed information. Regarding both efficacy and safety, the key for successful reversal of neuromuscular blockade is to use neostigmine “appropriately,” optimizing the dosage and timing of administration under close monitoring.

Half a century of anesthesia for children: An interview with Dr. Nishan G. 'Nick' Goudsouzian

The career of Dr Nishan Goudsouzian spanned half a century of pediatric anesthesia. His 50 years saw seminal contributions to the use of neuromuscular blocking agents in children, the development of proton beam therapy and magnetic resonance imaging for pediatric cancer, the introduction of the laryngeal mask airway, an explosion in the volume and depth of knowledge about pediatric anesthesia, the expansion of formal training in pediatric anesthesia, and the widening of academic efforts to improve anesthetic care for children worldwide. Based on interviews with Dr Goudsouzian, this article reviews the contributions of this Robert M. Smith Award winner to the development of pediatric anesthesia.

Pediatric Anesthesia Historical Perspective

This article examines how anesthesia evolved to serve the needs of children. Discussion includes milestones in technologic advancement related to pediatric anesthetic care and how collaboration among pediatric surgeons, neonatologists, and pediatric anesthesiologists has helped our specialty to progress. Conversely, the significant contributions of pediatric anesthesiology to pediatric critical care medicine, pain management, and pediatric public health care are also presented.

Edrophonium antagonism of cisatracurium-induced neuromuscular block: dose requirements in children and adults

This randomized, controlled study compared edrophonium dose requirements to antagonize cisatracurium-induced neuromuscular block in children and adults. Sixty children, aged two to 10 years, and 60 adults aged 20 to 60 years, all subjects ASA physical status 1 or 2, having propofol, fentanyl and isoflurane-N2O anaesthesia, were studied. Cisatracurium 0.1 mg x kg(-1) was given for muscle relaxation. Neuromuscular block was monitored with accelerometry. Edrophonium 0.1, 0.2, 0.4 or 1 mg x kg(-1) or no anticholinesterase (controls) was given by random allocation to antagonize 90% neuromuscular block in each of the study groups (n=12). Atropine 5 to 10 microg x kg(-1) was given according to edrophonium dose. Onset time of cisatracurium-induced block in children was mean (SD) 2.4 (0.8) versus 4.1 (2.3) minutes in adults, P<0.01. The times to 10% spontaneous recovery of the first twitch (T1) were respectively, 28.4 (5.2) and 41.8 (6.1) minutes in children and adults, P<0.01. Spontaneous and antagonist assisted neuromuscular recovery was more rapid in children. Adequate neuromuscular recovery (train of four (TOF) ratio 80%) was achieved in children at 3 and 10 minutes after edrophonium 1.0 mg kg(-1) and 0.4 mg x kg(-1), respectively. A TOF ratio of 80% was not achieved, within 10 minutes, with any of the four dose levels of edrophonium in adults. The dose of edrophonium to achieve a TOF ratio of 80% (ED(TOF-80)) after 5 and 10 minutes in children were, respectively, mean (SD) 0.85 (0.38) and 0.38 (0.19) mg x kg(-1). The equivalent ED(TOF-80) in adults was outside the edrophonium dose range studied.

Can the human neonate mount an endocrine and metabolic response to surgery?

Little is known of the ability of the human newborn infant to mount an endocrine and metabolic response to surgical trauma. Blood concentrations of glucose, lactate, pyruvate, alanine, hydroxybutyrate, acetoacetate, and glycerol together with plasma concentrations of insulin, glucagon, adrenaline, and nonadrenaline were measured in 33 infants (26 term, 7 preterm) subjected to surgery during the neonatal period. The results show that newborn infants can indeed mount a substantial endocrine and metabolic stress response, the main features of which are hyperglycemia and hyperlactatemia associated with the release of catecholamines and the inhibition of insulin secretion. There are specific differences between preterm and term neonates and between neonates anesthetised by different anesthetic techniques in the pattern of this response.

Dose requirement of d-tubocurarine and metocurine used for chronic respiratory paralysis in neonates

Nondepolarizing muscle relaxants are being used with increasing frequency in neonatal intensive care units. However, information concerning the chronic use of these agents and their dose requirements of d-tubocurarine and metocurine in neonates in whom respiratory paralysis was used as an adjunct to mechanical ventilation. All infants with gestational age greater than or equal to 38 wk demonstrated a dramatic daily increase in dose requirement of metocurine during the initial 8 days. However, infants with gestational age greater than or equal to 33 wk did not demonstrate a statistically significant daily increase in dose requirement. The 4 infants who received metocurine for more than 10 days exhibited a plateau of the dose requirement after 8-10 days. In contrast to the infants receiving metocurine, infants who received d-tubocurarine did not demonstrate a significant change in daily dose requirement. Four infants who received metocurine and four who received d-tubocurarine had acute renal failure and were not included in the above analysis. These infants had a significantly decreased dose requirement compared to the expected dose requirement for infants of comparable gestational age. There was no relationship between the dose requirement and the pH, serum potassium, or the use of aminoglycoside antibiotics.

Respiratory paralysis to improve oxygenation and mortality in large newborn infants with respiratory distress

The nonsynchronous respiratory efforts of neonates with surgically correctable disorders may inhibit effective mechanical ventilation. The records of 25 infants treated with metocurine for muscular paralysis to improve mechanical ventilation were reviewed. All patients were greater than 35 (37.6 +/- 2.1) weeks gestation and 2.27 (2.98 +/- .47) kg. All required ventilatory support with an FiO2 of 100%. The mortality rate of this group of infants was 20% as compared with 73% (p < .001) in a similar group of 26 infants managed without paralysis. In 10 of the 25 infants treated with metocurine, pre- and 1 hr postparalysis paO2 values were available. The mean paO2 prior to paralysis was 62 (45--111) mm Hg and the mean post-paralysis paO2 was 144 (75--227) mm Hg, representing at 132% increase in paO2 (p < .001). The mean dosage for metocurine was 3.5 (1.45--6.79) mg/kg/day; however, those requiring paralysis for greater than 7 days showed a dramatically increasing requirement. These preliminary data suggest that respiratory paralysis reduces right-to-left shunting, improves paO2 and decreases mortality in large infants with severe respiratory distress requiring ventilatory support.

Pharmacology and use of muscle relaxants in infants and children

Succinylcholine is a short-acting depolarizing neuromuscular blocker used to facilitate intubation; pancuronium is a longer-acting, nondepolarizing agent commonly employed to control ventilation in pediatric patients. The neuromuscular block produced by both drugs may be modified by patient age, acid-base and electrolyte status, body temperature, and drugs such as aminoglycoside antibiotics; adjustment in dose or in technique of administration may be required. Cardiovascular side-effects, primarily arrhythmias, are occasionally associated with the use of either agent. In contrast to that of succinylcholine, the paralysis from pancuronium is pharmacologically reversible with the combination of atropine and neostigmine.

Paediatric pharmacology

Infants and children differ pharmacologically from adults because the progressive maturation of various systems during development leads to variations in drug action and dosage. These differences are reviewed. Pharmacogenetic factors which affect anaesthesia and the problems of drug overdosage, as seen in paediatric intensive care units, are briefly considered.