Anne B. Hill

Incidence of choledochoduodenal sphincter spasm during fentanyl-supplemented anesthesia.

One hundred patients were studied prospectively to assess the incidence of spasm of the choledochoduodenal sphincter during biliary tract surgery performed under a fentanyl-supplemented anesthetic technique. The incidence of failure of passage of contrast medium into the duodenum was 3%. In each of the three patients with cholangiographic evidence of sphincter spasm, contrast medium flowed freely into the duodenum after the intravenous administration of 2 mg of glucagon. It is concluded that spasm of the choledochoduodenal sphincter is an uncommon occurrence during fentanyl-supplemented anesthesia and that this method of anesthesia is suitable for biliary tract surgery.

A Hypoxic Pulmonary Vasoconstrictor Response in Dogs during and after Infusion of Sodium Nitroprusside

The effect of sodium nitroprusside (SNP) on the pulmonary vasoconstrictor response to alveolar hypoxia was assessed by measuring the redistribution of blood flow in response to unilateral hypoxia. Ten dogs were anesthetized with thiopental and pentobarbital and a double-lumen endotracheal tube was inserted to permit separate ventilation of right and left lungs. Tidal volumes were maintained constant and redistribution of blood flow to each lung was followed by recording the radioactivity of mixed expired gas during the continuous intravenous infusion of 133Xe. The pulmonary vasoconstrictor response was tested by ventilating the left lung with oxygen, 7 per cent, followed by 100 per cent nitrogen before, during and after an intravenous infusion of SNP. The experimental sequence was then repeated. Unilateral hypoxia consistently decreased blood flow to the hypoxic lung (P<0.02), and there was no significant difference in flows during nonhypoxic conditions. Following infusion of SNP at a rate sufficient to decrease the mean arterial pressure to 80 torr there was a significant increase in flow (P<0.01) to the nonhypoxic lung in response to both degrees of hypoxia. The second infusion of SNP blunted the pulmonary vasoconstrictor response to anoxia (P<0.001), but the first infusion produced no significant blunting of response to either level of hypoxia. Arterial oxygen tension values increased significantly (P<0.05) during hypoxic conditions following SNP infusion and were significantly decreased (P<0.05) during the second infusion of SNP. These results suggest that SNP may increase arterial hypoxemia by depressing the homeostatic diversion of blood flow away from hypoxic areas of the lung; on discontinuation of SNP, there may be an increased protective response to hypoxia.

Plasma levels and cardiovascular effects of nitroglycerin in pregnant sheep

The cardiovascular effects and blood levels of intravenous nitroglycerin in mother and foetus were studied in normotensive and hypertensive ewes. Although nitroglycerin produced a reduction in uterine blood flow following a decrease in blood pressure, there was little if any incidence of adverse effects in the foetus. Nitroglycerin was detected in all but two samples of foetal arterial blood but the foetal/maternal artery ratio was only 0.04. Nitroglycerin merits further evaluation for the treatment of acute hypertensive episodes in the preeclamptic patient.RésuméLes effets cardiovasculaires et le niveau sanguin maternel et foetal de la nitroglycérine ont été étudiés chez la brebis normotensive et hypertensive. Bien que la nitroglycérine ait causé une diminution du débit sanguin utérin à la suite de la baisse de la tension artérielle, on n’a pu constater que peu ou pas d’effets nocifs sur le foetus. La nitroglycérine a été détectée dans tous les échantillons de sang artériel foetal à l’exception de deux et le rapport entre le sang foetal et maternel n’a été que de 0.04. La nitroglycérine mérite une évaluation plus approfondie pour le traitement de la crise hypertensive de la parturiente pré-éclamptique.

SEVERE HYPERTENSION ASSOCIATED WITH PANCURONIUM IN A PATIENT WITH A PHAEOCHROMOCYTOMA

There are a number of factors to consider in choosing a muscle relaxant for patients with a phaeochromocytoma. It has been suggested that pancuronium is the muscle relaxant of choice.1-3 This report describes a severe hypertensive response associated with pancuronium in a patient undergoing surgery for the removal of a phaeochromocytoma.RésuméOn doit tenir compte de plusieurs facteurs lorsqu’il faut administrer un myorésolutif pour l’anesthésie du malade porteur de phéochromocytome. On a préténdu que le pancuronium pouvait être le myorésolutif de choix. Cette observation décrit une crise hypertensive grave associée au pancuronium survenue chez un patient pendant l’exérèse d’un phéochromocytome.

Helium-oxygen mixtures in airway obstruction due to thyroid carcinoma.

The management of a patient with severe airway obstruction secondary to a thyroid mass is reported. When breathing room air the patient appeared in severe respiratory distress but when inspiring 22 per cent oxygen in helium she reported almost instantaneous relief and there was a marked decrease in respiratory rate, and increase in tidal volume and arterial oxygen tension. This improvement was to be expected because in situations where turbulent flow predominates a decrease in the density of inspired gases will result in an increase inflow rates. Contrary to established dogma a marked improvement was sustained when the patient was breathing 50per cent oxygen in helium. The concentraton of oxygen in helium was adjusted to obtain subjective relief for the patient in conjunction with adequate oxygenation.RésuméLa conduite devant une obstruction des voies aériennes secondaire à une masse thyroidienne est décrite. Quand la patiente respirait de l’air il apparaissait une détresse respiratoire sévère cependant lorsqu’elle inspirait un mélange de 22 pour cent doxygène et helium elle notait presqu’ instantanément un soulagement avec une diminu-tion marquée de la fréquence respiratoire et une augmen-tation de volume courant et de la tension oxygine artérielle. Cette amélioration était prévisible car pour des situations où le flot turbulant prédomine une diminu-tion de la densité des gaz inspirés provoquera une augmentation du flot. Contrairement au dogme dijd établi une amélioration marquée était soutenue lorsque la patiente respirait un melange de 50 pour cent oxygène et helium. La concentration d’oxygène et helium étail ajustée afin d’obtenir un soulagement subjectif et une oxygénation adequate.

A Comparison of Methods of Blood Withdrawal and Sample Preparation for Potassium Measurements

The effect on measured potassium values of a number of factors involved in sample acquisition and preparation were investigated. Measured potassium values in either plasma or serum were not influenced by the site of sample withdrawal, the presence of a tourniquet, or the time elapsed between blood sampling and analysis. However, increasing heparin concentrations and/or volumes decreased potassium values. The highest values were obtained in samples obtained in a syringe that had been washed with minimum volumes of heparin. It is concluded that this common clinical practice is based on a sound scientific rationale.

Effect of protamine on plasma ionized calcium in the dog.

Ten anaesthetized, heparinized healthy adult dogs were infused with protamine sulphate 3 mg.kg-1 and plasma ionized calcium was measured. A significant (p < 0.01) decrease in ionized calcium occurred which preceded the maximal reduction in cardiac output and systemic arterial pressure. The clinical implications of these results are discussed.RéSUMéOn a mesuré le calcium plasmatique ionisé après l’administration de sulfate de protamine à la dose de 3 mg.kg-1 chez dix chiens normaux, héparinisés, sous anesthésie générale. On a observé une diminution significative (p < 0.01) du calcium ionisé. Cette diminution précédait la diminution maximale du débit cardiaque et de la pression artérielle que l’on a observée. Les implications cliniques de ces résultats sont discutées.

Termination of cardiopulmonary bypass facilitated by insulin

A 61‐year old woman with severe coronary artery disease underwent three‐vessel coronary bypass surgery. Difficulty was encountered in terminating cardiopulmonary bypass, but there was dramatic improvement following the administration of intravenous insulin. The use of insulin to facilitate termination of cardiopulmonary bypass is discussed.