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Biomedical subjects

W L Roy

Publications and source records attributed to W L Roy.

22 records · Page 2Linked to original sources
PubMed1985

Intraoperative aspiration in a paediatric patient.

Aspiration around uncuffed endotracheal tubes in paediatric patients is an uncommon event. Uncuffed endotracheal tubes are commonly used in paediatrics even when the risk of gastric aspiration is significant. A case history is presented of an 81/2-year-old who aspirated during a laparotomy for bowel obstruction. The patient was intubated with an uncuffed #6.0 Portex endotracheal tube. A small leak was noted during positive pressure ventilation. The aspiration was significant such that the patient required 24 hours of positive end-expiratory pressure (PEEP) in an intensive care unit. Uncuffed endotracheal tubes are used because post-intubation stridor is minimized, the lungs are compliant and the funnel-shaped trachea is more likely to secure the airway from aspiration. An uncuffed tube however, does not completely seal the airway, particularly in the presence of an audible "leak." As a result of this case, we now consider the use of a cuffed endotracheal tube in children whenever a 5.5 internal diameter or larger is required. When the risk of pulmonary aspiration is present, the cuff is inflated to reduce the likelihood of contamination of the airway.

Airway Obstruction↗
PubMed1985

Fentanyl pharmacokinetics and hemodynamic effects in preterm infants during ligation of patent ductus arteriosus.

A bolus of 30 micrograms X kg-1 fentanyl was given to nine preterm infants (gestational age 31.8 +/- 4.7 weeks, weight 1100 +/- 309 g) for induction of anesthesia for ligation of a patent ductus arteriosus. Thirty minutes after the injection, fentanyl plasma concentrations were between 7.7 and 13.6 ng X ml-1. Elimination half-life was 6-32 hr (mean +/- SD, 17.7 +/- 9.3). Systolic blood pressure remained stable throughout surgery. There was a gradual increase in heart rate from 159 +/- 12 min-1 at the time of skin incision to 173 +/- 15 min-1 at the time of skin closure (P less than 0.05). Fentanyl plasma concentrations remained virtually unchanged between 30 min (10.6 +/- 1.9 ng X ml-1) and 120 min (9.6 +/- 1.6 ng X ml-1); whereas at the end of surgery most infants moved and breathed spontaneously. This phenomenon can be explained by redistribution of fentanyl from brain into pharmacodynamically inert tissues.

Anesthesia, Intravenous↗
PubMed1979

Myocardial ischemia during non-cardiac surgical procedures in patients with coronary-artery disease.

The purpose of this study was to determine the incidence of ST-segment depression during anesthesia and operation. Graded exercise testing has demonstrated a high correlation between ST-segment depression and myocardial ischemia. Therefore, 11 patients without and 29 patients with known coronary-artery disease were monitored during surgical procedures with a commercially available exercise electrocardiographic monitor (Viagraph). Comparisons were made between this device, which monitored lead V5, and the standard operating room monitor, which monitored lead 11. Eleven of 29 patients in the disease group demonstrated significant ST depression. Nine of the 11 ischemic episodes were not recognized on the standard operating room monitor. Retrospective review of anesthetic records of those 11 patients with ST-segment depression revealed rate--pressure product values greater than 11,000 for ten of them. Postoperatively, three of the 11 patients with significant ST-segment depression had changing electrocardiograms compatible with ischemia. None of the control group demonstrated significant ST-segment depression. The incidence of ischemia was 38 per cent during anesthesia and operation in the coronary-artery-disease group. Lead V5 analysis is superior to lead 11 analysis in detecting ST-segment depression. The period in which intubation is performed is one of the highest-risk intervals during anesthesia and operation, particularly when it is associated with an increased rate--pressure product.

Anesthesia, General↗