Search PubMed⌕ Search

Biomedical subjects

S L Snowdon

Publications and source records attributed to S L Snowdon.

45 records · Page 3Linked to original sources
PubMed1981

Comparison of respiratory characteristics during enflurane and halothane anaesthesia.

The effects of enflurane on certain respiratory characteristics were compared with those of halothane in 70 patients during anaesthesia with spontaneous breathing using a specially designed circuit. The rate of respiration with enflurane (mean 22 b.p.m.) was slower than with halothane (mean 31 b.p.m.; P less than 0.001) and the tidal volume greater (enflurane mean 240 ml, halothane 180 ml; P less than 0.05). There was no statistically significant difference in the minute volume of ventilation or end-tidal carbon dioxide concentration between the two agents. The effects of a narcotic premedication were observed in 16 patients in the study. The main effect was to produce slowing of respiratory rate (enflurane mean 16 b.p.m.; halothane 18 b.p.m.). The value of the respiratory pattern compared with the measurement of heart rate and arterial pressure as a clinical guide during anaesthesia is discussed.

Adolescent↗
PubMed1981

Blood pressure changes resulting from aortography.

Patients requiring aortography frequently suffer from generalized arteriosclerosis. Uncontrolled hypotension is therefore clearly undesirable, especially if associated with myocardial depression. Significant hypotension was observed following the use of conventional ionic contrast media, Urografin 370 and Cardioconray, and occurred following every injection in this study. Metrizamide, a non-ionic contrast medium, was found to be associated with a smaller fall in blood pressure of a shorter duration.

Aortography↗
PubMed1981

Cardiovascular and renal effects of enflurane and halothane in the dog.

A comparison between the effects of increasing concentrations of enflurane and halothane on cardiovascular and renal function in the artificially ventilated dog showed that both agents produced myocardial depression which was directly related to the concentration administered. Depression was more marked, and occurred at a lower minimum alveolar concentration (MAC) value with enflurane. No significant difference was found between the effects of the two agents on renal blood flow, glomerular filtration rate, renal vascular resistance or urine production at anaesthetic concentrations of 1 MAC. However, there was evidence of sudden depression of renal function as concentrations of enflurane were raised above 1 MAC, but with halothane a similar deterioration did not appear until the concentration of the inhalational agent reached 2 MAC.

Anesthesia, Inhalation↗
PubMed1975

The circle system without absorber. Use with controlled ventilation.

An investigation is described into the performance of two types of circle system used without a carbon dioxide absorber in both the laboratory and in the operating theatre with controlled ventilation. The newer system was found to be more efficient than the old but in both types of system the tidal volume was found to be very important, a large tidal volume resulted in increased efficiency. The possibility of predicting arterial blood carbon dioxide using this system is briefly discussed, and rules are suggested for the use of the system.

Absorption↗
PubMedDate not supplied

Failure of a ventilator alarm to detect patient disconnection.

An East Ventilator pressure monitor, Model VPM, used with an East Radcliffe PNA I Ventilator, failed to detect a patient disconnection at the distal end of the catheter mount. An investigation was undertaken to show why this system failed by measuring pressure and flow whilst using a variety of catheter mounts. It was concluded that the use of the East Ventilarm pressure monitor in conjunction with a pressure generator ventilator is unsuitable for detecting disconnections at the distal end of the catheter mount, the most frequent site of disconnection. Possible alternative methods of detecting this type of disconnection are suggested.

Catheterization↗