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Biomedical subjects

P K Caves

Publications and source records attributed to P K Caves.

At least 19 recordsLinked to original sources
PubMed1979

Role of angiotensin II in the development of peripheral vasoconstriction during cardiopulmonary bypass.

The possible relationship between angiotensin II -- the end product of the renin-angiotensin system, and the increase in peripheral vasoconstriction associated with cardiopulmonary bypass, has been investigated in 12 patients undergoing elective open-heart surgical procedures. Plasma angiotensin II (AII) levels were measured by radio-immunoassay at the start and the end of the period of cardiopulmonary bypass. Measurements of peripheral vascular resistance index were made at the times of AII sampling. Plasma AII levels rose during CPB from 78.0 to 231.3 pg.cm-3 (normal values less than 35 pg.cm-3). Peripheral vascular resistance index also rose during perfusion from 20.87 to 27.83 units. The rise in plasma AII levels and in peripheral vascular resistance index were correlated for each of the 12 patients. A highly significant correlation was obtained (r = 0.91; P less than 0.001). These results confirm the presence of parallel rises in plasma angiotensin II levels and in peripheral vasoconstriction during conventional non-pulsatile cardiopulmonary bypass, and suggest that increased plasma AII levels may be principal causative factor in the increased vasoconstriction associated with open-heart surgical procedures.

Adult↗
PubMed1978

Return to work after coronary artery surgery for angina.

The working habits of 115 consecutive patients who underwent coronary artery vein bypass grafting for angina were assessed. Only 25 patients worked up to the operation. Seven patients were housewives and seven retired. Sixty-eight patients had had to give up work because of their angina pectoris, and most of these had been off work for between six months and two years. After the operation 75 patients returned to full-time work, 59 within two to six months. These 75 patients included 23 of the 25 at work preoperatively and 47 of the 68 unable to work preoperatively. Most patients returned to their original occupation. We conclude that coronary artery surgery, as well as bringing symptomatic relief, increases the patient's ability to return to and maintain gainful employment.

Adult↗
PubMed1978

Anterior pituitary response to thyrotrophin-releasing hormone during open-heart surgery.

The anterior pituitary response to thyrotrophin-releasing hormone has been studied in 20 patients submitted to elective open-heart surgical procedures, and in six control patients submitted to closed mitral valvotomy. Standard non-pulsatile normothermic perfusion was used in all the open-heart cases. 400 microgram thyrotropin-releasing hormone was administered by intravenous injection during bypass, at 30 min post-bypass, and at 60 min post-bypass. The same dose (400 microgram) was given during closed mitral valvotomy (Control Group). Thyrotrophin-releasing hormone administration during bypass failed to produce a normal response from the anterior pituitary, in contrast to the normal response pattern seen in the control group (P less than 0.01). Thyrotrophin-releasing hormone given after the period of bypass produced responses within the normal range in the majority of patients. These results suggest that anterior pituitary hypofunction may exist during the period of extracorporeal circulation using non-pulsatile perfusion and that recovery of pituitary function is evident within the first hour post-extracorporeal circulation.

Cardiac Surgical Procedures↗
PubMed1978

Aortic valve replacement in rheumatoid aortic incompetence.

Rheumatoid aortic valve disease is uncommon. and there are few reports of valve replacement in this condition. Aortic valve replacement and partial pericardiectomy was performed in a patient with acute rheumatoid aortitis and aortic incompetence. Previous reports suggest that any patient with rheumatoid arthritis who develops cardiac symptoms should be carefully assessed for surgically treatable involvement of the pericardium or heart valves.

Animals↗
PubMed1978

Comparative studies of pulsatile and nonpulsatile flow during cardiopulmonary bypass. III. Response of anterior pituitary gland to thyrotropin-releasing hormone.

Previous studies have indicated that, during nonpulsatile cardiopulmonary bypass, the anterior pituitary gland fails to respond to the tropic stimulus of thyrotropin-releasing hormone (TRH). This is in contrast to the normal response seen during closed cardiac and general surgical procedures. The Stöckert pulsatile pump system described in Part I has been employed in a comparative study of TRH responses in 20 patients subjected to pulsatile or nonpulsatile perfusion during open-heart surgery. In the nonpulsatile group, a consistently subnormal response to TRH injection was again found. In the pulsatile group, however, the pituitary response to TRH was normal in nine patients out of 10. The quantitative difference between the groups was statistically highly significant (p less than 0.005). These results indicate that the subnormal pituitary function seen with nonpulsatile bypass may be prevented by the use of pulsatile perfusion.

Adult↗
PubMed1978

Comparative studies of pulsatile and nonpulsatile flow during cardiopulmonary bypass. I. Pulsatile system employed and its hematologic effects.

A new, commercially available roller pump system able to deliver pulsatile and nonpulsatile flow has been studied in patients undergoing elective open-heart surgical procedures. The pulsatile pump (Stöckert Instrumente) may be used with standard extracorporeal circuit equipment and consistently produces a peripheral arterial pulse pressure of 25 to 30 mm. Hg at mean flow rates of 3.5 to 4.0 L. per minute. Twenty patients, arbitrarily allocated to pulsatile or nonpulsatile groups, have been studied. There were no significant differences between the groups in respect of age, weight, bypass time, pump flow, or mean arterial pressure during bypass. Comparative studies of the hematologic effects of pulsatile and nonpulsatile perfusion were carried out. There was no evidence of increased hemolysis with pulsatile flow, nor was there increased depletion of red blood cells (RBC's) or platelets in the pulsatile group. This pulsatile pump system may therefore be used to produce pulsatile perfusion during cardiopulmonary bypass without the fear of producing excessive blood cell trauma.

Adult↗
PubMed1978

Comparative studies of pulsatile and nonpulsatile flow during cardiopulmonary bypass. II. The effects on adrenal secretion of cortisol.

Previous studies have indicated that a significant reduction in plasma cortisol levels occurs during nonpulsatile cardiopulmonary bypass as a result of adrenocorticol hypofunction. The Stöckert pulsatile pump system described in Part I has been employed in a comparative study of plasma cortisol levels in 20 patients subjected to pulsatile or nonpulsatile perfusion during open-heart surgery. The plasma cortisol response pattern in the nonpulsatile group was identical to the pattern previously described, with no significant rise in cortisol levels during the period of perfusion. In the pulsatile group, however, plasma cortisol levels rose significantly during perfusion, reaching a mean level at the end of perfusion which was highly significantly greater than that in the nonpulsatile group (p less than 0.001). Correction of the plasma cortisol values for the effect of hemodilution was performed and, again, corrected cortisol values indicated a highly significant increase in end-bypass levels in the pulsatile groups (p less than 0.001). These results clearly indicate that the reduction in cortisol secretion during nonpulsatile bypass may be prevented by the use of pulsatile perfusion.

Adrenal Glands↗
PubMed1977

Traumatic rupture of the ascending aorta and aortic valve following blunt chest trauma.

Traumatic rupture of the aorta at the level of the isthmus is a well-recognized injury following blunt chest trauma. By contrast, rupture of the ascending aorta and of the aortic valve in a road traffic accident is rare and does not appear to have been previously reported. The occurrence of such an injury in a 56-year-old man involved in a road traffic accident is reported. The diagnosis was made preoperatively following aortography and successful surgical correction involved aortic valve replacement with resection and grafting of the damaged area of the ascending aorta. The probable mechanisms involved in the production of this unusual injury are discussed.

Accidents, Traffic↗
PubMed1977

Pathological changes in spontaneous rupture of chordae tendineae.

Eight patients with spontaneous rupture of mitral chordae tendineae have been studied. In no case was there a predisposing cause. Seven showed pathological fibrosis of the papillary muscle relevant to the ruptured chordae. It is postulated that papillary msucle dysfunction secondary to fibrosis may cause stretching of chordae and subsequent rupture. Five patients had mucoid degeneration of their mitral valves. Mucoid change appeared to develop only when the clinical history indicated a lengthy period of valvular dysfunction.

Aged↗
PubMed1976

Anomalous origin of the left coronary artery from the pulmonary artery with coronary artery steal in adults. Report of two cases and review of the literature.

Patients with anomalous left coronary artery arising from the pulmonary artery rarely survive to adult life. Those who attain adulthood may present with angina indistinguishable from coronary artery disease and are liable to sudden death. Myocardial infarction, though rare in young adults, may occur and may be due to coronary artery steal. Accurate diagnosis requires coronary arteriography. Two further cases of coronary artery steal in adults with anomalous origin of the left coronary artery from the pulmonary artery are presented. In both patients aortocoronary bypass grafting using a reversed autogenous saphenous vein with closure of the origin of the anomalous left coronary artery was successfully performed. This operation provided complete symptomatic relief and may protect patients against the risk of sudden death.

Adolescent↗
PubMed1976

Surgical management of ventricular septal defect complicating myocardial infarction.

In an 18 month period six patients were treated by operation for ventricular septal defect occurring as a complication of acute myocardial infarction. Each septal defect occurred within one week of the myocardial infarct but the interval from infarction to operation ranged from 8 days to 7 months. All patients had intractable cardiac failure and two were in cardiogenic shock at the time of operation. Preoperatively right and left heart catheterisation with left ventriculography and biplane coronary arteriography was performed in every case. At operation the principle of "total correction" of all the cardiac defects was followed so that in addition to closure of the septal defect each patient required one or more additional operative procedures such as resection of left ventricular infarct or aneurysm, mitral valve replacement or coronary artery vein bypass grafts. All six patients survived operation but one died four weeks postoperatively from perforation of an acute peptic ulcer. In one patient the ventricular septal defect recurred and was successfully closed four months later. The surviving patients remain well at follow-up.

Acute Disease↗
PubMed1975

Left atrial myxoma: diagnosis, treatment, and cytological observations.

A patient first seen with cardiac cachexia was found to have a large left atrial myxoma. The diagnosis was first suggested by echocardiographic examination. Cure was achieved by surgery. Light and electron microscopic studies indicate a multipotential mesenchymal cell origin of myxomata.

Cardiac Catheterization↗
PubMed1975

Effect of intercostal nerve blockade during operation on lung function and the relief of pain following thoracotomy.

The use, during operation, of intercostal nerve blocks with lignocaine and bupivacaine for the relief of pain following thoracotomy was assessed in 138 patients. Irrespective of the method used to evaluate efficacy, it was not possible to demonstrate a lasting effect of clinical significance favouring either local anaesthetic agent. This form of treatment, although free from serious side effects, had no beneficial effects on lung function and is not recommended for the relief of pain following surgery.

Blood Pressure↗