Biomedical subjects
M Lye
Publications and source records attributed to M Lye.
Is there a relationship between supine systemic blood pressure and orthostatic hypotension in the elderly?
The relationship between blood pressure and orthostatic hypotension was studied in 48 elderly patients with orthostatic hypotension and 29 healthy age-matched controls. Individuals were designated as hypertensive (systolic > 160 and or diastolic > 90 mmHg) or normotensive on the basis of supine blood pressure levels. Systolic, diastolic and mean blood pressures, heart rate, stroke volume, cardiac output, cardiac index and total peripheral resistance were measured every 5 min before, during and after 10 min head-up tilt to 70 degrees. Eighteen orthostatic hypotension subjects and six controls were hypertensive, while 30 orthostatic hypotension subjects and 23 controls were normotensive. There were no differences between hypertensive and normotensive patients in mean age, weight, height or body surface area. Mean systolic blood pressure in orthostatic hypotension subjects was higher than in controls (148.8 +/- 3.6 vs. 137.5 +/- 3.34 mmHg). Mean diastolic pressure was not different (79.1 +/- 2.0 vs. 79.0 +/- 2.0 mmHg). There were no differences between patients with or without hypertension in the haemodynamic changes produced by head-up tilt. Heart rates in orthostatic hypotension subjects with hypertension were significantly lower throughout the study when compared with normotensive orthostatic hypotension patients. Further, the increases in heart rate on tilting were significantly smaller (8.4 +/- 1.9 vs. 14.5 +/- 1.8 beats/min). Control hypertensive subjects had significantly higher mean cardiac output and cardiac index compared with non-hypertensives from before and during tilt. We conclude that hypertension is not related to the development or the degree of orthostatic hypotension in the elderly.(ABSTRACT TRUNCATED AT 250 WORDS)
Arterial oxygen saturation and posture in acute stroke.
Patients with acute stroke are at risk of hypoxaemia and the degree of oxygen desaturation may depend on posture. Using a fingertip pulse oximeter, we studied the effects of different nursing positions on arterial oxygen saturation (SaO2) in ten elderly patients within 48 hours of a hemiplegic stroke and 10 age-matched controls admitted to hospital with other acute illnesses. Mean SaO2 was consistently higher in the controls than the stroke patients in all recumbent positions, but when patients were propped up the difference between the groups was statistically insignificant. The difference between semirecumbent and lying SaO2 values was then tested in a further nine stroke patients. Overall the mean SaO2 was significantly higher and, in at least four cases, the duration of episodes of desaturation (SaO2 < 90%) was substantially less when the patients were propped up. We suggest that, wherever possible, acute stroke patients should be nursed sitting up to minimize the risk of oxygen desaturation and possible aggravation of ischaemic brain damage.
Effect of xamoterol in a patient with idiopathic autonomic failure.
We report the effect of xamoterol on autonomic, humoral and haemodynamic function in a patient with idiopathic autonomic neuropathy. Xamoterol produced marked symptomatic improvement, slightly increased heart rates in the sitting, supine and upright tilt positions and higher blood pressures while seated and on recovery from upright tilt. There were, however, no differences in blood pressure responses following a meal or during head-up tilt. We suggest that before ascribing symptomatic benefit to xamoterol in this condition, objective haemodynamic improvement should be recorded. Further studies of treatment in idiopathic autonomic failure require to be placebo controlled.
Attitudes of elderly patients to medical students.
The attitudes of elderly patients towards clinical teaching of medical students was assessed by a structured interview carried out by a doctor unknown to the patient immediately prior to discharge. One hundred and thirty alert patients were approached on three acute geriatric medicine wards in the Royal Liverpool (Teaching) Hospital. A total of 106 (81.5%) patients were suitable for inclusion in the study (mean age, 80.2 years). Twenty-nine per cent did not know what a medical student was despite having been interviewed and examined by one. Fifty-nine per cent of patients had no prior knowledge that clinical teaching occurred. Fourteen patients (13 women, 1 man, P < 0.05) objected to being examined. Nineteen women patients were examined by a man student without a chaperone. Students usually (95%) asked permission to interview and examine the patients whereas doctors only asked patients in the context of bedside teaching (33%). Elderly patients were sympathetic towards ('They have to learn') and positive about ('It's good to have them') medical students. However, 29% of patients were not aware that a medical student was going to be a doctor despite being interviewed and examined. We suggest that the term should be used either with explanation or abandoned in favour of 'student doctor'. The level of awareness of clinical teaching was poor and examination of women patients without a chaperone caused distress and should be rectified.
Bacteriuria in non-catheterized elderly patients in the first eight days of hospital stay.
One hundred and sixty-one non-catheterized consecutive acute geriatric admissions were screened for bacteriuria on the day following admission, both in the morning and in the afternoon and seven days later--morning and afternoon. The prevalence of bacteriuria was 29% on admission. A correlation between bacteriuria and leucocyturia was shown. The patients were admitted with a variety of medical illnesses but in no case was a diagnosis of urinary-tract infection made prior to admission. There was a significant relationship between incontinence and bacteriuria on admission; 12% of abacteriuric patients became bacteriuric between day 1 and day 7 following admission. Escherichia coli accounted for 51% of the isolates on admission to hospital. Bacteriuria was associated with increased mortality within 1 year following admission to hospital.
Haemodynamic and neurohumoral responses in elderly patients with postural hypotension.
Haemodynamic and neurohumoral responses to head-up tilt were measured in 28 elderly patients with postural hypotension (EPPH) and 12 healthy elderly subjects (HE). There were no differences in catecholamines between the groups and only noradrenaline increased on tilt (P less than 0.001). Plasma renin activity and aldosterone were similar in HE and EPPH in the supine and tilt positions. In both groups vasopressin increases (P = 0.032), and plasma volume decreases were the same (P = 0.673). Supine EPPH had higher heart rates (P = 0.019) but similar cardiac indices (P = 0.621). Both had similar changes on tilting (P = 0.975 and P = 0.341). Stroke volume decrease was higher in HE (35%) than EPPH (23%; P less than 0.001). HE showed an increase in peripheral resistance on tilting with no change in EPPH (P = 0.005). EPPH had larger coefficients of variation for all variables. The differences in haemodynamic responses and the similarity of neurohumoral responses during tilting suggest end-organ failure in EPPH with individual variations. Postural hypotension in old age is not a single entity.
Serum leucine-enkephalin in bronchial carcinoma and its relation to tumour location.
Serum concentrations of the opioid peptide leucine-enkephalin were measured by radioimmunoassay in 30 patients with histologically confirmed bronchial carcinoma and 10 control subjects. This peptide, which is present in greatest amounts in the central and autonomic nervous systems, has previously been found in bronchial neoplasms. The mean serum concentration of leucine-enkephalin was significantly greater in the patients with carcinoma (1035 pg/ml) than in the control subjects (426 pg/ml). In the 23 patients with a tumour in non-apical regions of the lung, however, the mean concentration of the peptide (422 pg/ml) did not differ significantly from that in control subjects; serum concentrations in the seven patients with an apical neoplasm (mean 3050 (range 1259-5820) pg/ml) were significantly greater than values in either the control subjects or the patients with non-apical lung tumours. All seven subjects with an apical tumour had one or more features of Horner's syndrome and the three with all four components of the syndrome had the highest serum concentrations. Serum concentrations of leucine-enkephalin were unrelated to tumour type or presence of metastatic disease. No patient had evidence of metastases in the central nervous system or adrenal glands. Raised serum concentrations of leucine-enkephalin in patients with an apical tumour probably reflect invasion of cervical sympathetic ganglia with release of the peptide into the circulation rather than elaboration of the peptide by the neoplasm.
Plasma growth hormone and digital clubbing in carcinoma of the bronchus.
Growth hormone is a secretory product of some primary bronchial neoplasms and has been associated with the development of hypertrophic pulmonary osteoarthropathy and acromegaly in occasional patients with such tumours; it has not, however, generally been considered important in the pathogenesis of digital clubbing. Plasma levels of growth hormone at the time of diagnostic bronchoscopy were measured in 60 patients with histologically proved bronchial carcinoma, divided according to whether clubbing was present (n = 21) or absent (n = 39), and in 13 control subjects undergoing the same procedure but with no neoplasm. The median plasma level of growth hormone ( and interquartile range) was 0.74 (0.5-1.0) mU/l in five control subjects with no pulmonary disease, 0.83 (0.4-1.3) mU/l in eight subjects with non-neoplastic pulmonary disease, 1.1 (0.6-3.3) mU/l in patients with carcinoma but without clubbing, and 3.1 (0.8-9.0) mU/l in 21 patients with carcinoma and clubbing. The highest growth hormone level was seen in a patient with a small cell carcinoma and pronounced clubbing; levels had fallen to normal by the time chemotherapy was completed and clubbing completely resolved. Thus growth hormone or a similar substance might have a role in the pathogenesis of clubbing in patients with bronchial neoplasms.
Hypernatraemia in the elderly patient.
The elderly are at risk of developing hypernatraemia because of age-related changes in renal function and body composition. The pathophysiology and aetiology of hypernatraemia are reviewed with emphasis on iatrogenic factors. A rational approach to management is discussed and clear guidelines for treatment described.
Clinical prognostic indices of fatality in elderly patients admitted to hospital with acute pneumonia.
Acute pneumonia in the elderly is a common and serious condition. The importance of key clinical features and physical signs presenting to the junior hospital doctor was prospectively assessed in 100 consecutive patients admitted acutely to two hospitals. The most significant finding is that elderly patients with pneumonia who are found to be acutely confused at the time of presentation or who gave a previous history of chronic brain failure are much more likely to die than others. Thus such patients should be assessed with particular attention to the early diagnosis and vigorous treatment of pneumonia.
Pharmacokinetics of lisinopril (MK521) in healthy young and elderly subjects and in elderly patients with cardiac failure.
The pharmacokinetics of lisinopril were determined in 6 healthy young, 6 healthy elderly and 6 elderly patients with cardiac failure. Lisinopril (5 mg day-1) was administered for 7 days. Plasma lisinopril concentration was measured at 1, 2, 4, 6, 8 and 24 h on days 1 and 7 of the study. The two elderly groups had higher serum lisinopril concentrations than the healthy young subjects (P less than 0.05). There were no significant differences in any of the areas under the curve (AUC) for lisinopril plasma concentration (over time) between the healthy young and healthy elderly groups. The healthy young patients had AUC values on day 7 lower than elderly patients with cardiac failure (P less than 0.01). Creatinine clearance was correlated with lisinopril clearance (r = 0.63; P = 0.006) and with AUC on day 7 (r = -0.67; P = 0.004). Lisinopril clearance was different in the three groups (P less than 0.05): healthy young patients had the highest and elderly patients with cardiac failure the lowest values. Thus, in the elderly a reduced renal clearance of lisinopril leads to higher and more sustained blood levels. In elderly patients with cardiac failure, renal function should be estimated before lisinopril is prescribed as a reduction in dose may be appropriate.
Diuretics and potassium in the elderly.
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Inappropriate prescribing in the elderly.
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Variability of blood pressure in postural hypotension in the elderly.
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Cardiovascular haemodynamics and the response of vasopressin, aldosterone, plasma renin activity and plasma catecholamines to head-up tilt in young and old healthy subjects.
Increasing age impairs the regulation of blood pressure during posture change. The neuro-humoral and cardiovascular responses to head-up tilt were analysed in carefully-screened young and healthy elderly individuals. Mean blood pressure was significantly higher in the elderly but there were no differences in total peripheral resistance, heart rate, stroke volume and cardiac index. Age-related interactions were observed in the control of mean blood pressure, heart rate and stroke volume. Total peripheral resistance increased and cardiac index decreased but there was no difference in their control in the young and old. Noradrenaline, vasopressin, plasma renin activity and aldosterone all increased in response to the tilt. These observations indicate differences in the neuroendocrine responses and cardiovascular haemodynamics of young and old healthy individuals to head-up tilt and are particularly important because of all observations were made simultaneously in the same subject. It is suggested that a similar approach should be adopted in the investigation of patients with postural hypotension.
Are cervical spine radiographs of value in elderly patients with vertebrobasilar insufficiency?
Radiographs of the cervical spine of 32 elderly patients clinically diagnosed as having vertebrobasilar insufficiency secondary to cervical spondylosis were compared with 32 age- and sex-matched controls. The mean age was 77.6 years. There was no significant difference in the severity of the radiological changes between the two groups as judged by the narrowing of disc space and marginal osteophyte formation. It is concluded that there is no place for routine examination of the cervical spine in patients thought to have vertebrobasilar insufficiency secondary to cervical spondylosis.
Analysis of circadian rhythms by fitting a least squares sine curve.
A method that fits a least squares sine curve to both point and averaged time series data is described. The method includes a full regression analysis and extends the current "cosinor" approach. Developments include estimation of the linear trend and fitting secondary wave forms.