Canadian journal of anaesthesia = Journal canadien d'anesthésie
-
Randomized Controlled Trial Comparative Study Clinical Trial
Clear fluids three hours before surgery do not affect the gastric fluid contents of children.
This prospective, randomized, single-blind study of 121 healthy children aged 2 to 12 yr investigated the effect of clear fluids on gastric contents. Gastric fluid volume and pH were measured immediately following the induction of general anaesthesia and were not significantly affected by the ingestion of unlimited clear fluids up to three hours preoperatively. ⋯ Gastric fluid volume (ml.kg-1) increased in both the control and study groups as age increased, P less than 0.005. It is concluded that drinking clear fluid up to three hours before scheduled surgery does not have a measurable effect on gastric volume and pH of healthy children of ages 2 to 12 yr.
-
Comparative Study
Occurrence of gastroesophageal reflux on induction of anaesthesia does not correlate with the volume of gastric contents.
In an attempt to explain the discrepancy between the high number of patients said to be at risk of aspiration pneumonitis and the low reported incidence of this anaesthetic complication, 100 ASA physical status I-II elective surgical patients were studied. The volume of fluid present in the stomach at the time of induction of anaesthesia was correlated with gastroesophageal reflux (GER) detected by visual inspection of the pharynx and by continuous measurement of upper oesophageal pH. Mean gastric volume was 30 +/- 28 ml (range 0-210 ml). ⋯ No GER was detected during induction of anaesthesia in our sample of 100 patients. Furthermore, patient age, duration of preoperative fasting, body mass index, cigarette smoking, alcohol consumption, preoperative anxiety, and a history of preoperative GER were not correlated with significant modifications of gastric volume or pH. We conclude that the low incidence of aspiration pneumonitis in elective surgical patients may be explained in part by the very low risk of GER, despite gastric fluid volumes of more than 0.4 ml.kg-1 in a high proportion of this patient population.
-
Case Reports
Negative pressure pulmonary oedema: a potential hazard of muscle relaxants in awake infants.
We report two cases of healthy infants who were given an IV intubating bolus of a nondepolarizing muscle relaxant (0.1 mg.kg-1 vecuronium) at the beginning of an inhalational induction of anaesthesia. Shortly after the introduction of low concentrations of gaseous agents, both infants exhibited airway obstruction although inspiratory muscle activity was still vigorous. The airway obstruction was due to approximation of the tongue to the posterior pharyngeal wall, and was easily corrected by insertion of an oral airway. ⋯ It is postulated that paralysis of glossal muscles occurred prior to diaphragmatic paralysis, creating upper airway obstruction while preserving inspiratory muscle activity. This can rapidly lead to negative pressure pulmonary oedema in the small infant. Meticulous attention to the maintenance of an unobstructed upper airway is required if muscle relaxants are administered to the awake infant.
-
The changes in the arterial to end-tidal carbon dioxide gradient. P(a-ET)CO2, were studied in postoperative cardiac surgery patients from the time of admission to the intensive care unit, during changing cardiorespiratory support, up to the time of tracheal extubation. Individual factors evaluated for their effects on P(a-ET)CO2 included rate of mechanical ventilation, infusion of vasoactive agents (nitroglycerin, nitroprusside, dopamine, dobutamine, and metariminol), and associated changes in haemodynamic pathophysiology (cardiac index, pulmonary artery pressure, pulmonary vascular resistance index, systemic vascular resistance index, and pulmonary capillary wedge pressure). ⋯ For many of the individual patients, however, the relationship between PaCO2 and ETCO2 did not maintain a significant correlation throughout the study period. In the postoperative cardiac surgery patient population P(a-ET)CO2 follows a normal distribution and PaCO2 and ETCO2 maintain a statistically significant correlation. However, when evaluating individual patients, this relationship has wide variability.
-
This case report describes intraoperative anaphylaxis occurring in a fourteen-year-old female with spina bifida in which latex surgical gloves were incriminated as the aetiologic agent. The patient was non-atopic but since eight years of age she had developed localized angioedema and urticarial skin reactions on exposure to rubber. She had previously undergone several uneventful surgical procedures. ⋯ Subsequent investigations for allergies demonstrated a strongly positive skin prick test and RAST to latex antigen, with negative results to anaesthetic agents, antibiotics and inhalant allergens. During two later operations prophylaxis consisting of diphenhydramine, ranitidine and hydrocortisone appeared to prevent further reactions. Latex should be considered as a cause of life-threatening intraoperative allergic reactions in patients with a history of rubber allergy or frequent exposure to latex products.