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Biomedical subjects

L McDonald

Publications and source records attributed to L McDonald.

At least 91 records · Page 5Linked to original sources
PubMed1978

Determination of brain death via pulsatile echoencephalography.

For cerebral death to occur there must be many levels of cerebral function destroyed. Cortical and subcortical irreversible damage is evident by unresponsiveness to any stimuli. Brain stem and basal ganglia damage is indicated by absence of spontaneous respirations, cephalic reflexes, and thus cerebral circulation. All elements of the criteria for cerebral death must be met. The decision should be made by the attending physician in consultation with his peers. The life support mechanisms should be discontinued after the diagnosis of cerebral death has been made. Absence of pulsatile echoes means absence of cerebral circulation and cerebral function, or a definitive diagnosis of cerebral death. It is a final parameter in the criteria and allows definite measures to be taken. But it behooves one to remember that this phenomenon of cerebral death makes organ donation and transplantation possible. It has not been created in order to supply the needs for organ transplant!

Adult↗
PubMed1977

Mitral regurgitation in coronary heart disease.

Mitral reguritation is a relatively common finding in coronary heart disease. In this series of 127 patients, selected with a view to coronary or left ventricular surgery on the basis of severity of symptoms, the incidence was 39 (31%). Mitral regurgitation is significantly more common in patients with a history or electrocardiographic evidence of previous myocardial infarction. Clinically it may present as a pan- or late systolic or even a mid-systolic, ejection type murmur at the apex or at the left sternal edge; but in 39 per cent of the patients with angiographic mitral regurgitation no murmur was present. Angiographically important mitral regurgitation (grades 2-4/4) was usually associated with a systolic murmur; this finding was independent of ejection fractions. Left ventricular enlargement clinically or radiographically is likely to accompany mitral regurgitation but left atrial enlargement (electrocardiographically or on chest x-ray) is a more reliable pointer to mitral regurgitation and pulmonary venous hypertension is even more strongly suggestive of its presence. The electrocardiographic signs of papillary muscle infarction were rare in this series (15%) and were not related to angiographic mitral regurgitation. There was no difference in the incidence of mitral regurgitation in association with anterior or inferior myocardial infarction or in distribution of coronary artery disease. There is, however, a higher incidence of mitral regurgitation in more severe coronary arterial disease (P less than 0-05). The incidence of mitral regurgitation is significantly higher with reduction in left ventricular ejection fraction (P less than 0-001), with rise in the left ventricular end-diastolic pressure (P less than 0-02), and with abnormal contraction patterns, but the severity of mitral regurgitation is not significantly related to these findings.

Adult↗
PubMed1975

Coronary heart-attacks in East London.

All cases of cardiac infarction, acute coronary insufficiency and sudden death occurring in residents of the London Borough of Tower Hamlets below age 65 were registered over nearly three years, and survivors were followed up for one year. The attack-rate in men aged 45-64 years was 1 per 100 per annum but the recurrence-rate in survivors was 1 per 100 per month. Immigrants from Asia had more than the average, and those from the Carribean one tenth of the average attack-rate. Although it was unusual for general practitioners to manage cases at home by choice, nonetheless two-thirds of the deaths happened outside hospital and half of these were not witnessed. Half of those suffering coronary heart-attacks had a previous history of coronary disease and a sizable minority were already unfit for work. Approximately half of those attacked were alive at one year.

Acute Disease↗
PubMed1972

Venous graft surgery in treatment of coronary heart disease.

Sixty-seven patients have had aortocoronary venous graft bypass surgery by one surgeon for the relief of symptoms of severe coronary heart disease, including eight emergency operations. The overall operative, hospital, and late mortality was low in patients with favourable myocardial function and no previous myocardial infarction. There was a 7% mortality in patients with a normal preoperative chest radiogram, 8% mortality when the left ventricular end-diastolic pressure was normal preoperatively, and a 5% mortality in patients who had normal left ventricular angiograms. The overall mortality in all elective operations for cardiac pain resistant to medical treatment was 15.8%. 89% of survivors improved; 67% are pain-free. Exercise tolerance in survivors is increased by 135%, atrial pacing results are improved by 10%. Left ventricular end-diastolic pressure is unchanged. Left ventricular function on angiography is improved. The improvement in left ventricular function assessed objectively correlates positively with vein-graft patency, as does freedom from angina pectoris.

Adult↗