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Biomedical subjects

G D Murray

Publications and source records attributed to G D Murray.

At least 109 records · Page 6Linked to original sources
PubMed1991

Comparison of two methods for predicting difficult intubation.

Two methods of predicting difficult laryngoscopy were compared prospectively. Mallampati class and Wilson risk-sum were determined before operation and laryngeal view graded in 675 patients. Both tests identified five of 12 difficult laryngoscopies; twice as many patients were predicted to be difficult by Mallampati classification than by Wilson risk-sum. Inter-observer variation was minimal using Wilson risk-sum, but considerable for Mallampati classification. We prefer the Wilson risk-sum for assessment of the airway, while noting that both tests have poor sensitivities.

Adolescent↗
PubMed1991

Evaluation of potential pharmacodynamic and pharmacokinetic interactions between verapamil and propranolol in normal subjects.

1. Potential pharmacodynamic and pharmacokinetic interactions between verapamil and propranolol were evaluated in two double-blind, randomised, balanced, crossover studies employing the same six healthy males. 2. The first study examined the effect of repeated propranolol administration on the pharmacodynamics and pharmacokinetics of verapamil after single oral and intravenous doses. The second explored the pharmacodynamics and pharmacokinetics of verapamil and propranolol alone and in combination after single and repeated oral doses. 3. The magnitude of the prolongation of PR interval induced by oral and intravenous verapamil was not affected by pre-treatment with propranolol. When verapamil and propranolol were co-administered as single doses, effects on PR interval were additive but, following repeated doses, a trend towards greater than additive prolongation was seen. The arithmetic sum of the effects of the two drugs was 23% (95% C.I. 8-38%) but the measured increase after the combination was 40% (95% C.I. 26-54%). 4. The extent of reduction in heart rate and blood pressure at rest and after exercise following repeated doses of propranolol was not influenced by single oral or intravenous doses of verapamil. The heart rate and blood pressure responses to single and repeated oral doses of verapamil and propranolol in combination were significantly greater than those after either drug alone and approximated to the arithmetic sum of the individual responses. 5. Although repeated administration of propranolol reduced hepatic blood flow as assessed by indocyanine green clearance, there was no evidence of an interaction between the drugs at this level. 6. The pharmacokinetics of verapamil and norverapamil were not significantly affected by prior propranolol. After single doses of verapamil and propranolol in combination, the maximum plasma concentration of propranolol was increased and the oral clearance of verapamil reduced. No pharmacokinetic interaction was observed after repeated doses. 7. These findings provide little evidence of a pharmacodynamic or pharmacokinetic interaction between verapamil and propranolol in normal subjects. Most of the haemodynamic responses to these drugs in combination can be explained by additive drug effects but an interaction affecting AV conduction after repeated doses cannot be excluded. The minor pharmacokinetic interaction between the drugs is unlikely to be relevant to the pharmacodynamic changes.

Adult↗
PubMed1991

Cross-sectional assessment of caries and periodontitis risk within the same subject.

Dental caries and chronic periodontitis may be synergistically associated, negatively associated, or completely independent. The present report examines this relationship by comparing the susceptibility to chronic periodontitis and caries within the same individual. From an 800-patient sample, a periodontitis risk score was derived by radiographic assessment of bone loss in quarters of optimum bone height and obtaining for each subject a mean score based on all measurable surfaces. Similarly the caries risk was determined radiographically from the total decayed and filled teeth (DFT), as a percentage of the total teeth measured. The Mantel-Haenszel technique was used for analysis of the relationship between periodontitis and caries and data was stratified on four categories of age, sex, and numbers of teeth present. This analysis revealed no systematic patterns, indicating that the risks of caries and periodontal diseases are unrelated (chi 2 = 0.00; 1 df; P greater than 0.50). In addition, a regression analysis, which was controlled for sex and age, indicated a marked lack of association between caries and periodontitis (P = 0.94). Thus, although these common diseases share putative etiologic factors such as oral hygiene practices and dental attendance pattern, the major risk factors are probably quite different.

Adolescent↗
PubMed1991

Hemodynamic effects of a single moderate dose of alcohol in elderly subjects.

The effects of 0.5 g ethanol/kg body weight and of an iso-volumic control drink were compared in eight normotensive subjects aged 70-96 years. Blood alcohol concentration reached a mean (+/- SEM) maximum of 44.4 +/- 5.0 mg/dl at 50 minutes after the start of drinking. Compared to control, alcohol increased mean sitting and standing heart rates by 3.4 +/- 1.3 (p = .08) and 5.4 +/- 1.9 (p less than .05) beats/minute, respectively; mean venous haematocrit rose by 3.9 +/- 1.3% (p less than .05). There were no significant changes in sitting or standing systolic or diastolic blood pressures after alcohol compared to the control drink. A single moderate dose of alcohol has only minor haemodynamic effects in normotensive elderly subjects. The rise in heart rate after alcohol may be a reflex response that helps to maintain blood pressure in the face of reduced circulating plasma volume due to alcohol-induced diuresis.

Aged↗
PubMed1991

The Acute Infarction Ramipril Efficacy (AIRE) Study: rationale, design, organization, and outcome definitions.

The rationale, design, organization, and outcome definitions of the Acute Infarction Ramipril Efficacy (AIRE) Study are described prospectively. A total of 2,000 patients (1,000 per treatment group) will be recruited to this multicenter, multinational, double-blind, randomized, placebo-controlled study investigating the effect of oral treatment with ramipril (2.5 or 5 mg twice daily) on the total mortality of survivors of an acute myocardial infarction (AMI) with early clinical evidence of heart failure. Secondary outcomes of the study include progression to severe/resistant heart failure (at which time the patient will be withdrawn from the study treatment), reinfarction, and stroke. Treatment will be initiated in hospital between day 3 and day 10 following AMI, and follow-up continued for an average of 15 months and a minimum of 6 months. The study data will be analyzed on an intention-to-treat basis: a single formal interim analysis will be conducted after 175 deaths. An Independent Adjudicating Panel will act as the overall ethical supervisory body for the study and will retain the randomization code. An International Steering Committee will be responsible for the clinical definitions of the secondary study outcomes, and will regularly review progress of the study. We believe that early treatment with ramipril may reduce the total mortality of patients surviving an AMI with clinical evidence of heart failure.

Acute Disease↗
PubMed1990

Meta-analysis.

Explore the source record for details and available documents.

Humans↗
PubMed1990

Statistical comparison of two methods of clinical measurement.

The comparison of two measurement techniques, neither of which can be regarded as being a 'gold standard', is fundamental to much basic research. This apparently simple problem raises many statistical difficulties, which are reviewed in this paper in the context of anorectal manometry. It is concluded that a recently developed approach focusing on the agreement between the two techniques is far superior to the more conventional approach based on correlation. However, until the benefits of the new analysis are more widely recognized (and it is hoped that this paper is a step towards that goal), it is argued that it is useful to present both analyses in such comparisons of measurement techniques.

Air↗
PubMed1990

How we should approach the future.

There is little doubt that there are still major problems with the statistical aspects of published medical research. This paper argues that it is not sufficient to teach statistics to medical undergraduates, when the bulk of their courses are being taught by the very same individuals who continue to undertake and publish substandard research. Instead, any undergraduate teaching needs to advance in parallel with courses given to the clinical staff within medical schools.

Computer-Assisted Instruction↗
PubMed1990

Propranolol in the prevention of recurrent variceal hemorrhage in cirrhotic patients. A controlled trial.

A double-blind controlled study of long-acting propranolol in the secondary prevention of variceal hemorrhage was conducted in 81 cirrhotic patients. After the index hemorrhage, all patients were treated with injection sclerotherapy on one occasion to secure hemostasis and then randomized within 72 h to propranolol or placebo therapy which was continued for 2 yr. Study endpoints were severe recurrence of variceal hemorrhage or death. Forty-two patients did not fulfill the entry criteria for the study. Thirty-eight patients received propranolol of whom 18 (47%) had further hemorrhage, 14 died, eight had side-effects (2 withdrawals), and 3 did not complete follow-up. Forty-three patients received placebo of whom 33 (77%) had further hemorrhage, 19 died, 5 had side-effects (2 withdrawals), and 5 failed to complete follow-up. The median time from onset of hemorrhage to starting drug therapy was 6 days for both groups. Life table analysis showed an equivalent incidence of further hemorrhage in both groups over the first 60 days, following which the propranolol group did consistently better than the placebo group. There was a significantly lower incidence of rebleeding in modified Child's C patients receiving propranolol (39%) than those on placebo (90%). No statistically significant effect on mortality was seen. In this study, propranolol reduced the incidence of late recurrence of variceal hemorrhage in patients with cirrhosis.

Double-Blind Method↗
PubMed1990

Haemostatic abnormalities and outcome in patients with operable breast cancer.

The predictive value for cancer recurrence of five measurements of haemostatic activity was studied in 89 patients with operable breast cancer. Neither preoperative nor sequential measurements up to 9 months postoperatively of fibrinopeptide A, fibrin fragment B beta 15-42, fibrinogen and serum fibrin(ogen) degradation products nor the fibrin plate lysis assay correlated with early recurrent disease. B beta 15-42 values were higher preoperatively in patients with oestrogen receptor positive tumours (P = 0.017). Mean B beta 15-42 values rose postoperatively (P = 0.003), largely because of an increase in patients with oestrogen receptor negative tumours.

Adult↗
PubMed1990

The effects of treating hypertension following aneurysmal subarachnoid hemorrhage.

We investigated in a consecutive series of 134 patients with aneurysmal subarachnoid hemorrhage whether institution of antihypertensive treatment was related to the incidence of cerebral ischemia and rebleeding. The aim of hypertensive treatment was to reduce the diastolic blood pressure to levels below 100 mm Hg. There was no difference in outcome between patients with or without antihypertensive drugs. Rebleeding was less frequent in patients with antihypertensive treatment (12/80 patients (15%) versus 18/54 patients (33%) without anti-hypertensive treatment (p = 0.012)). Nevertheless, patients with anti-hypertensive treatment had, on average, still higher blood pressures than untreated patients. Conversely, infarction occurred more often in patients with anti-hypertensive treatment (34/80 patients (43%) versus 12/54 (22%) without antihypertensives (p = 0.03)). This relationship was partly explained by co-existing hyponatremia. Our results suggest that the need for antihypertensive treatment is questionable, since the prevention of rebleeding is offset by an increased risk of cerebral infarction.

Antihypertensive Agents↗
PubMed1990

Left ventricular hypertrophy and mortality in hypertension: an analysis of data from the Glasgow Blood Pressure Clinic.

Three thousand seven hundred and eighty-three patients with non-malignant hypertension attending the Glasgow Blood Pressure Clinic between 1968 and 1983 were followed prospectively for an average of 6.5 years. Left ventricular hypertrophy (LVH) was present at the outset in 34.5% of the men, and 12.8% had ST-T changes. The corresponding figures for women were 21.5% and 8.8%. The prevalence of LVH increased with the severity of hypertension and was higher for a given blood pressure level in men than in women. All-cause age-adjusted mortality, expressed as deaths per 1000 patient-years, was 27.6 for men with normal electrocardiographs, 43.2 for men with LVH only (P less than 0.001) and 56.9 for men with LVH and ST-T changes (P less than 0.001). Similar trends were seen in women. The excess risk associated with LVH, with or without ST-T changes, could not be explained by age, increased blood pressure at referral to the clinic, or smoking habit, when these factors were considered either separately or in combination (regression analysis). Thus, our study demonstrates that LVH, with or without ST-T changes is an independent risk factor for mortality in hypertensive patients.

Age Factors↗
PubMed1989

Effect of oral nimodipine on cerebral infarction and outcome after subarachnoid haemorrhage: British aneurysm nimodipine trial.

OBJECTIVE: To determine the efficacy of oral nimodipine in reducing cerebral infarction and poor outcomes (death and severe disability) after subarachnoid haemorrhage. DESIGN: Double blind, placebo controlled, randomised trial with three months of follow up and intention to treat analysis. To have an 80% chance with a significance level of 0.05 of detecting a 50% reduction in an incidence of cerebral infarction of 15% a minimum of 540 patients was required. SETTING: Four regional neurosurgical units in the United Kingdom. PATIENTS: In all 554 patients were recruited between June 1985 and September 1987 out of a population of 1115 patients admitted with subarachnoid haemorrhage proved by the results of lumbar puncture or computed tomography, or both. The main exclusion criterion was admission to the neurosurgical units more than 96 hours after subarachnoid haemorrhage. There were four breaks of code and no exclusions after entry. One patient was withdrawn and in 130 treatment was discontinued early. All patients were followed up for three months and were included in the analysis, except the patient who had been withdrawn. INTERVENTIONS: Placebo or nimodipine 60 mg was given orally every four hours for 21 days to 276 and 278 patients, respectively. Treatment was started within 96 hours after subarachnoid haemorrhage. END POINTS: Incidence of cerebral infarction and ischaemic neurological deficits and outcome three months after entry. MEASUREMENTS: Demographic and clinical data, including age, sex, history of hypertension and subarachnoid haemorrhage, severity of haemorrhage according to an adaptation of the Glasgow coma scale, number and site of aneurysms on angiography, and initial findings on computed tomography were measured at entry. Deterioration, defined as development of a focal sign or fall of more than one point on the Glasgow coma scale for more than six hours, was investigated by using clinical criteria and by computed tomography, by lumbar puncture, or at necropsy when appropriate. All episodes of deterioration and all patients with a three month outcome other than a good recovery were assessed by a review committee. MAIN RESULTS: Demographic and clinical data at entry were similar in the two groups. In patients given nimodipine the incidence of cerebral infarction was 22% (61/278) compared with 33% (92/276) in those given placebo, a significant reduction of 34% (95% confidence interval 13 to 50%). Poor outcomes were also significantly reduced by 40% (95% confidence interval 20 to 55%) with nimodipine (20% (55/278) in patients given nimodipine v 33% (91/278) in those given placebo). CONCLUSIONS: Oral nimodipine 60 mg four hourly is well tolerated and reduces cerebral infarction snd improves outcome after subarachnoid haemorrhage.

Administration, Oral↗
PubMed1989

Comparison of enalapril and atenolol in mild to moderate hypertension.

PURPOSE: Short-term therapy with angiotensin converting enzyme (ACE) inhibitors for hypertension is effective and well tolerated, and compared with beta blockers, may cause fewer adverse reactions. Furthermore, enalapril has been observed to have a greater effect on systolic blood pressure than beta blockers. We therefore decided to compare the ACE inhibitor enalapril and the beta blocker atenolol as monotherapy in a double-blind study of patients with mild to moderate hypertension. PATIENTS AND METHODS: After a four-week placebo run-in period, 162 patients were allocated randomly to receive atenolol (50 to 100 mg daily) or enalapril (20 to 40 mg daily) for 12 weeks. To assess the influence of these drugs on quality of life, a series of psychologic tests was performed, and a subset of patients also underwent treadmill exercise and pulmonary function tests. RESULTS: In 147 patients who completed the study, enalapril reduced supine blood pressure by 19/12 mm Hg, compared with 9/7 mm Hg for atenolol (p less than 0.001/p less than 0.005). The modest blood pressure response to atenolol was not due to poor compliance. A target blood pressure of 140/90 mm Hg or less was achieved by 35 percent of enalapril-treated atenolol (p less than 0.01). The frequency and severity of adverse effects with the two drugs were similar, and few important differences emerged from the quality-of-life assessments. CONCLUSION: At the doses used, enalapril induced a greater short-term blood pressure response than atenolol; long-term studies of its safety and efficacy are required.

Adolescent↗
PubMed1989

International study of ketanserin in Raynaud's phenomenon.

PURPOSE: The effects of ketanserin on primary or secondary Raynaud's phenomenon due to connective tissue disease were studied in a large, international group of patients. PATIENTS AND METHODS: The study population consisted of 222 patients from 10 countries. After a run-in period of one month of placebo therapy, patients were randomly assigned in a double-blind manner to receive ketanserin 40 mg three times daily (n = 113) or placebo (n = 109) for three months. Total finger blood flow was measured in 41 patients in a warm and cool room before and during treatment. Vasospastic episodes were assessed by diaries and global evaluations. RESULTS: A significant reduction of 34% in frequency of episodes occurred with ketanserin, compared to 18% with placebo (p = 0.011). There was a 1% reduction in duration of episodes with ketanserin therapy, compared to a 2% increase with placebo therapy, but this finding was not statistically significant (p = 0.29). No difference was observed in severity of attacks. Global evaluations by investigators (p = 0.03) and patients (p less than 0.01) showed an overall benefit with ketanserin compared to that seen with placebo. Patients with primary or secondary Raynaud's phenomenon responded similarly to treatment. No changes in total finger blood flow were found. CONCLUSION: Ketanserin significantly improves the subjective symptoms of patients with primary or secondary Raynaud's phenomenon and is an appropriate agent to use in this disease when conservative measures fail.

Blood Pressure↗
PubMed1989

Short-term tranexamic acid treatment in aneurysmal subarachnoid hemorrhage.

Antifibrinolytic treatment for 4 weeks after a subarachnoid hemorrhage has been shown to have no effect on outcome since a reduction in the rate of rebleeding was offset by an increase in ischemic events. To determine if a shorter course (4 days) of antifibrinolytic treatment before the expected onset of ischemic complications might reduce the rate of rebleeding yet avoid ischemic complications, we prospectively studied a series of 119 patients with subarachnoid hemorrhage; 479 patients with subarachnoid hemorrhage from our previous randomized double-blind study (238 treated with placebo, 241 with long-term tranexamic acid) served as historical control groups. At 3 months' follow-up, the outcome of patients treated with short-term tranexamic acid was not different from that of patients treated with long-term tranexamic acid. The rate of rebleeding (24 of 119, 20%) was near that with placebo (56 of 238, 24%). In contrast, the rate of cerebral infarction (33 of 119, 28%) was almost identical to that after long-term tranexamic acid (59 of 241, 24%), although mortality from cerebral infarction was reduced. Compared with historical control groups, treatment with tranexamic acid for 4 days fails to reduce the incidence of rebleeding but still increases the rate of cerebral infarction.

Cerebral Angiography↗
PubMed1989

Effect of fludrocortisone acetate in patients with subarachnoid hemorrhage.

In this study with randomized controls, we administered fludrocortisone acetate to 46 of 91 patients with subarachnoid hemorrhage in an attempt to prevent excessive natriuresis and plasma volume depletion. Fludrocortisone significantly reduced the frequency of a negative sodium balance during the first 6 days (from 63% to 38%, p = 0.041). A negative sodium balance was significantly correlated with decreased plasma volume during both the first 6 days (p = 0.014) and during the entire 12-day study period (p = 0.004). Although fludrocortisone treatment tended to diminish the decrease in plasma volume, the difference was not significant (p = 0.188). More patients in the control group developed cerebral ischemia (31% vs. 22%) and, consequently, more control patients were treated with plasma volume expanders (24% vs. 15%), which may have masked the effects of fludrocortisone on plasma volume. Fludrocortisone therefore reduces natriuresis and remains of possible therapeutic benefit in the prevention of delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage.

Clinical Trials as Topic↗