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Biomedical subjects

H A Dudley

Publications and source records attributed to H A Dudley.

At least 19 recordsLinked to original sources
PubMed1979

Sequential patterns of haemodynamic and metabolic changes in experimental hypovolaemic shock. I. Responses to acute haemorrhage.

Little is known about cardiorespiratory changes during the development of hypovolaemia. This study attempts to provide such information and compares the period of bleeding with that of established hypovolaemia. Eleven anaesthetized and ventilated greyhounds were bled and analyses of cardiopulmonary function made at fixed intervals both during and after haemorrhage. Six sequential patterns of cardiopulmonary and metabolic change were recognized. It was apparent that bleeding caused the first three phases of change, recovery from the effects of bleeding the next two and steady hypovolaemia the last. The event of bleeding is the main factor that elevates total peripheral resistance and reduces tissue perfusion with consequent lowering of oxygen consumption and alkalosis secondary to impaired carbon dioxide production; when bleeding ceases these changes partially reverse in a manner characteristic of that induced by the reinfusion of shed blood; and hypovolaemia per se has a relatively weak influence. These findings provide an explanation for disparities in previous published reports and have obvious clinical implications.

Animals↗
PubMed1979

Sequential patterns of haemodynamic and metabolic changes in experimental hypovolaemic shock. II. Responses to reinfusion of shed blood.

The haemodynamic and metabolic effects which follow the infusion of blood in experimental hypovolaemia have not been studied in detail. The 10 dogs that survived 90 min of hypovolaemia in a study of bleeding (Pardy and Dudley, 1979) were investigated during and shortly after the reinfusion of shed blood using the same techniques. Data from 9 animals were suitable for analysis. As with bleeding, 6 sequential phases were identified; reinfusion of blood was completed in the fifth phase. Initial reinfusion was associated with a rapid improvement in haemodynamic and metabolic status, although mean arterial pH fell because carbon dioxide production increased. Maximum metabolically effective tissue perfusion was probably attained in phase II, but haemodynamic improvement continued until phase IV. Arterial pH did not rise above the pre-infusion value until phase V, and this rise was the result of a fall in PaCO2 secondary to a reduction in physiological dead space and an increase in buffering capacity. Pulmonary artery pressure was superior to systemic artery pressure as a predictor of cardiac output during blood volume restoration. A number of conclusions pertaining to clinical practice are drawn.

Animals↗
PubMed1978

Assessment of suture materials for intestinal use by an extramucosal implant technique and a quantitative histological evaluation.

Six suture materials, 5 of which are in common use for intestinal suture, were implanted in the small and large bowel of the rabbit, and thereafter the durability of their tensile strength and the histological reaction produced were assessed at standard times over 64 days. Absorbable sutures (catgut and polyglycolic acid) lose strength too rapidly to provide reliable sole support, though the synthetic absorbable produces only a slight reaction. Non-absorbables maintain their strength. Only minor differences exist between the reactions produced by different non-absorbables. Other considerations such as handling characteristics or the results of clinical work should be borne in mind in the selection of the optimum suture material.

Animals↗
PubMed1978

Osmolar output in the peri-operative period.

The hourly urine volume and urine concentration of seven patients undergoing major abdominal surgery were measured during the operative and postoperative periods. From these, the hourly osmolar output was calculated. The results show that the osmolar output, 700 mOsm/day, in the peri-operative period is less than that of a 70 kg man consuming a normal 2000 calorie diet. Calculation of the osmolar output might help in the differentiation of postoperative oliguria and renal dysfunction.

Abdomen↗
PubMed1977

Micro-ergonomics.

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Ergonomics↗