William L. McNiece

Respiratory obstruction from uvular edema in a pediatric patient.

A 20-month-old 10.8-kg boy was admitted as an outpatient for electroretinography under general anesthesia. He had an uneventful anesthetic with tracheal intubation at age 6 months for electroretinography. There was no family history of anesthesia-related problems. He had no known allergies and was receiving no medicines. He had a recent history of mild coryza without other evidence of upper respiratory tract infection. Preoperative physical examination and complete blood count were normal except for mild coryza. After establishment of an intravenous infusion and the intravenous administration of atropine, anesthesia was induced with thiopental followed by succinylcholine. After ventilation with 100% oxygen by mask, the trachea was intubated uneventfully with a 4.0-mm inside diameter orotracheal tube. Anesthesia was maintained with halothane and nitrous oxide-oxygen using assisted ventilation. At the conclusion of the 50-min procedure, the anesthetic gases were discontinued, and after demonstration of the presence of protective airway reflexes, the pharynx was suctioned and the trachea extubated. The chdd was taken to the recovery room and placed in a mist tent with an F I ~ ~ of 0.26. The recovery room course was uneventful, and after a 45-min stay, he was dressed and carried in an upright position to an adjacent waiting area. Forty-five minutes later as the child was moved from a recumbent to upright po-

Anaesthesia and pyruvate dehydrogenase deficiency

A ten-month-old infat with pyruvate dehydrogenase deficiency received anaesthesia on two occasions, once for a laparotomy and once for a trachecstomy. During both anaesthetics (different techniques) she developed an increase in arterial lactate levels and a metabolic acidosis. Pyruvate dehydrogenase deficiency results in the inability to metabolize pyruvate with resultant accumulation of pyruvate and lactate. Inhibition of gluconeogenesis, which may be produced by halothane and thiopentone, will also increase lactate levels. Other causes of increased lactate levels are hypocarbia and high carbohydrate intake. In this patient hypocarbia may have produced increased lactate levels and increased the metabolic acidosis. Recommendations include avoidance of halogenated anaesthetics, avoidance of lactate containing solutions, maintenance of normocarbia, and stress-free anaesthesia.RésuméUn enfant de dix mois déficient en déshydrogénase pyruvique a été anesthesia à deux occasions; pour laparotomie et pour trachéotomie. Deux techniques différentes ont été utilisées. Lors de deux opérations, il a développé une acidose métabolique et une élévation des concentrations artérielles d’acide lactique. La déficience enzymatique en déshydrogénase pyruvique produit une altération du métabolisme de l’acide pyruvique avec comme résultat accumulation d’acide pyruvique et d’acide lactique.L’inhibition de la glyconéogénèse que l’on peut rencontrer avec l’halothane et le thiopental, provoquera aussi chez ces malades une augmentation des concentrations d’acide lactique. D’autres causes d’acidose lactique comprennent l’hypocarbie et l’apport imponant de glucides. Chez ce patient, l’hypocarbie peut avoir augmenté l’acidose métabolique et les concentrations d’acide lactique.Nous recommandons d’éviter les halogènes ainsi que les solutions contenant de l’acide lactique, de maintenir une normocarbie et d’administrer une anesthésie suffisamment profonde pour protéger du stress chirurgical.

Effect of thiopental and succinylcholine on serum potassium concentrations in children.

Succinylcholine increases serum potassium levels in normal adults by 0.25-0.8 mEq/L (1,2). The magnitude of the increase in potassium is decreased when thiopental or methohexital are used for induction of anesthesia (3,4). Pretreatment with diazepam, hexafluorenium, pancuronium, or fazadinium also prevents succinylcholine-induced serum increases in potassium (2,5-7). Henning and Bush found that after halothane induction of anesthesia, succinylcholine increased serum potassium by a mean of 0.45-0.48 mEq/L in children (8). Keneally and Bush reported that potassium increased by an average of 0.23 mEq/L following succinylcholine after thiopental induction (4 mg/kg) in children less than 5 yr old (9). There were no significant changes in children 6-16 yr old. In these studies of children, premedication was not controlled and alveolar ventilation was not monitored. In the present study we examined the effects of succinylcholine on venous serum potassium concentrations after thiopental induction (6 mgkg) of general anesthesia in healthy, unpremedicated children. Ventilation was controlled to maintain end-tidal C02 within the normal range.

Anaesthetic implications of neonatal necrotizing enterocolitis

A retrospective analysis of infants with necrotizing enterocolitis was done to evaluate the effects of preoperative abnormalities upon anaesthesia and mortality. Mortality was significantly increased in infants weighing less than 1500 grams (p < .001). Sixty-nine per cent of the infants had hyaline membrane disease and 35 per cent had platelet counts less than 50 x 109 cells/litre (50,000/mm3). Perioperative problems include peritonitis, sepsis, hypovolaemia, acidosis, and prematurity. Other ramifications of prematurity and anaesthesia are discussed.RésuméLes auteurs ont fait la revision des dossiers de trente deux enfants opérés pour entéro-colite nécrosante du nouveau-né. Le but de l’étude était de mettre en évidence l’impact des anomalies pré-opératoires sur la mortalité et la conduite de l’anesthésie. La mortalité totale a été de 53 pour cent (17/32). On a observé entre autres: 1) une mortalité plus élevée (p < 0.001) chez les bébés de moins de 1500 g. 2) un syndrome de membrane hyaline chez 69 pour cent des patients et 3) un décompte plaquettaire inférieur à 50 x 109/litres (50,000/mm3) dans 35 pour cent des cas. Parmi les principaux problèmes péri-opératoires, on a relevé la péritonite, l’état septique, l’hypovolémie, l’acidose et la prématurité. La conduite de l’anesthésie et les problèmes liés à la prématurité sont discutés.