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Biomedical subjects

T Treasure

Publications and source records attributed to T Treasure.

At least 91 records · Page 5Linked to original sources
PubMed1994

Which patients will not benefit from further intensive care after cardiac surgery?

In intensive care units, a predictive model that identified patients who are certain to die would spare suffering and free resources for more productive work. In a prospective study to determine factors which might predict the outcome of a protracted stay in intensive care units, information was collected for 162 patients who remained in intensive care longer than 48 hours after cardiac surgery. Of these patients, 21% presented as emergencies, 35% as urgent cases, and 44% as elective cases. They were drawn from 2256 adult patients operated upon during a 12-month period in three UK centres. 115 patients (71%) who were in intensive care for more than 48 hours survived to be discharged. The median duration of stay was 6 days (range 3-90 days) and the median duration of hospital stay was 21 days (7-111 days). An existing algorithm developed and calibrated to predict outcome for general patients in intensive care was applied to forecast outcomes. Contrary to expectations, the algorithm performed well for patients after cardiac surgery. In identifying deaths in intensive care and before hospital discharge, the specificities for death at various intervals after admission were all 97% or more. There is little scope for improving the algorithm's ability to forecast longer term outcome. Furthermore, if it were to be introduced to aid decisions about withdrawal of treatment, the potential saving in intensive care bed-days would be small--less than 3% overall.

APACHE↗
PubMed1994

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Cardiac Surgical Procedures↗
PubMed1994

Pacing thresholds of temporary epicardial electrodes: variation with electrode type, time, and epicardial position.

We compared the variation in pacing thresholds of two widely used temporary pacing electrodes at different epicardial sites in 67 patients after coronary artery operations performed with either cardioplegia or ventricular fibrillation. In 33 patients, a bare, braided pacing wire (DW) was placed on the right ventricle and a Medtronic localized epicardial electrode (MED), on each ventricle. In the other 34 patients, the DW wire was placed on the right atrium and a MED electrode, on each atrium. Pacing thresholds were measured at the time of placement; at 1 hour, 6 hours, and 12 hours postoperatively; and daily for 4 days. The pacing thresholds (mean +/- standard error of the mean) at implantation were as follows: DW wire = 0.93 +/- 0.08 V and MED electrode = 0.63 +/- 0.1 V in the ventricles and DW = 1.28 +/- 0.18 V and MED = 0.65 +/- 0.09 V in the atria. On the fourth postoperative day, the pacing thresholds were DW = 2.08 +/- 0.21 V and MED = 1.19 +/- 0.22 V in the ventricles and DW = 2.33 +/- 0.29 V and MED = 1.04 +/- 0.09 V in the atria. The pacing thresholds of both types of wire increased significantly over time, but this deterioration was more pronounced with the braided wire both on the ventricle and on the atrium. The pacing threshold patterns were not affected by chamber side or mode of myocardial preservation. The braided ventricular wire failed to capture after 24 hours in 9 of 30 patients, whereas the localized epicardial electrode captured in all instances (p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Pacing, Artificial↗
PubMed1994

Comparison of two strategies for myocardial management during coronary artery operations.

Despite the current trend for using blood cardioplegia, ventricular fibrillation with intermittent ischemia is still used as a strategy to manage the myocardium with impressive results. These two methods of myocardial management were compared in 40 patients undergoing elective coronary artery operations using creatine kinase MB isoforms and troponin T assays. Each patient was randomized to have either cold blood cardioplegia (n = 20) or ventricular fibrillation with intermittent ischemia (n = 20) for myocardial management during the construction of distal anastomoses. Until recently, the comparison of different methods of myocardial management has been hindered by the lack of a specific and sensitive marker of myocardial damage. Analysis of creatine kinase MB isoforms (MB2, cardiac tissue form; MB1, plasma-modified form) and cardiac-specific troponin T (a structural protein) has been shown to improve the sensitivity for the detection of myocardial damage. There were no significant differences between the two groups in age, sex ratio, extent of disease, or left ventricular function. Blood samples for analysis were collected before cross-clamp application and at time intervals up to 48 hours after. Median peak creatine kinase MB2 activity was found to be significantly higher in the blood cardioplegia group compared with ventricular fibrillation (26.5 U/L versus 19.5 U/L, respectively, p = 0.04). Although median peak troponin T concentration was higher in the blood cardioplegia group, the difference failed to reach significance (2.2 ng/mL versus 1.6 ng/mL, p = 0.15).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Pericardiectomy using an ultrasonic dissector.

We report the case of a 73-year-old man on whom we performed pericardiectomy for calcified constrictive pericarditis using an ultrasonic dissector. It seems unlikely that others have not used the technique, but it does not feature in the standard operative descriptions.

Aged↗
PubMed1994

Pre-operative aspirin decreases platelet aggregation and increases post-operative blood loss--a prospective, randomised, placebo controlled, double-blind clinical trial in 100 patients with chronic stable angina.

Aspirin has an established benefit in reducing the incidence of coronary events and vein graft occlusion. We have now assessed the risk of pre-operative aspirin in a prospective, randomised, double-blind clinical trial in 100 patients scheduled for elective coronary artery surgery. Any prescribed aspirin and non-steroidal anti-inflammatory drugs were discontinued 2 weeks pre-operatively and these were replaced by a randomly assigned tablet of either aspirin 300 mg daily or placebo taken until the day of surgery. Patient compliance was confirmed by serum and urinary salicylate analysis. The two groups were similar in demographic characteristics, bypass time, number of grafts placed and number of internal mammary arteries used. All patients survived to be discharged home (see Table). Aspirin decreases platelet aggregation to arachidonic acid and to collagen both pre- and post-operatively. The benefit of pre-operative aspirin has to be balanced against the risk of increasing post-operative blood loss, re-exploration for excessive bleeding and transfusion requirements.

Aspirin↗
PubMed1994

Aprotinin inhibits fibrinolysis, improves platelet adhesion and reduces blood loss. Results of a double-blind randomized clinical trial.

The present recommendation is that aprotinin should be started before cardiac surgery, but as bleeding is only a problem in a minority, most patients are treated unnecessarily. In a prospective, randomised, double-blind trial we have studied the use of aprotinin, given only to the minority of patients who bled significantly post-operatively and who had not received prophylactic aprotinin. Sixty patients, who bled in excess of 400 ml in the first 3 h post-operatively were randomised to receive either aprotinin (2 x 10(6) KIU loading dose followed by an infusion of 0.5 x 10(6) KIU/h for 4 h) or placebo, in addition to conventional treatment. The demographic characteristics and the surgical procedures performed were similar in the two groups. Haematological variables were measured (A) before and (B) at the end of the infusion. Three patients were re-explored for excessive bleeding in each group and one patient died in each group. The patients in the aprotinin group bled significantly less and had higher haemoglobin levels on discharge than the patients in the placebo group. The tissue plasminogen activator antigen decreased and the fibrinogen level increased in the aprotinin group. In addition, aprotinin increased the number of surface GPIb platelet receptors as estimated by flow cytometry (36% versus 5%, P < 0.01) and maintained the platelet von Willebrand Factor activity (vWF). There was no significant difference in D-dimers, fibrin(ogen) degradation products, plasma vWF activity and antigen, platelet vWF antigen, platelet aggregation (to collagen, arachidonic acid, platelet activating factor and ristocetin), platelet count or transfusion of blood products between the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Influence of endothelium and surgical preparation on responses of human saphenous vein and internal thoracic artery to angiotensin II.

1. The saphenous vein (SV) and internal thoracic artery (ITA) are the most commonly used conduits for coronary artery bypass surgery (CABS). The ITA shows better long term patency than the SV, at least in part due to their different responses to agonists, as well as physical differences between the ITA and SV at the time of grafting. 2. Angiotensin II (A II), a potent endogenous vasoconstrictor circulates at augmented levels during and after CABS, but little is known about the effects of A II on the SV and ITA. 3. We studied the contractile effects of A II on SV and ITA as intact rings from a heterogeneous group of patients undergoing CABS. Two groups of SV samples were studied; freshly excised SV (FSV) with no further manipulation and SV that had been surgically prepared for use as a bypass conduit (PSV). We also assessed the function of the endothelium in FSV, PSV and ITA, by measuring the relaxation of preconstricted rings to bradykinin. In some tissues endothelial presence was examined histologically. 4. Surgical preparation of SV affected the contractile ability of the smooth muscle, as PSV contracted less than FSV to potassium chloride (KCl, 90 mM) (P < 0.0001). Loss of endothelial function was seen in 25% of FSV, 50% of PSV and 33% of ITA. 5. A II caused concentration dependent contractions in all rings, over the same concentration range (1 nM-100 nM). In rings of FSV the presence of functional endothelium attenuated the response, median values with endothelium being less than half that without endothelium (P < 0.0007, at 100 nM).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

QT interval in anorexia nervosa.

OBJECTIVES: To determine the incidence of a long QT interval as a marker for sudden death in patients with anorexia nervosa and to assess the effect of refeeding. To define a long QT interval by linear regression analysis and estimation of the upper limit of the confidence interval (95% CI) and to compare this with the commonly used Bazett rate correction formula. DESIGN: Prospective case control study. SETTING: Tertiary referral unit for eating disorders. SUBJECTS: 41 consecutive patients with anorexia nervosa admitted over an 18 month period. 28 age and sex matched normal controls. MAIN OUTCOME MEASURES: maximum QT interval measured on 12 lead electrocardiograms. RESULTS: 43.6% of the variability in the QT interval was explained by heart rate alone (p < 0.00001) and group analysis contributed a further 5.9% (p = 0.004). In 6 (15%) patients the QT interval was above the upper limit of the 95% CI for the prediction based on the control equation (NS). Two patients died suddenly; both had a QT interval at or above the upper limit of the 95% CI. In patients who reached their target weights the QT interval was significantly shorter (median 9.8 ms; p = 0.04) relative to the upper limit of the 60% CI of the control regression line, which best discriminated between patients and controls. The median Bazett rate corrected QT interval (QTc) in patients and controls was 435 v 405 ms.s-1/2 (p = 0.0004), and before and after refeeding it was 435 v 432 ms.s1/2 (NS). In 14(34%) patients and three (11%) controls the QTc was > 440 ms.s-1/2 (p = 0.053). CONCLUSIONS: The QT interval was longer in patients with anorexia nervosa than in age and sex matched controls, and there was a significant tendency to reversion to normal after refeeding. The Bazett rate correction formula overestimated the number of patients with QT prolongation and also did not show an improvement with refeeding.

Adolescent↗
PubMed1994

An unusual cause of dysphagia: a vascular ring.

A 40 year old woman presented with dysphagia which was due to one of the forms of vascular ring. Her symptoms were relieved by relatively conservative surgery. The means of diagnosis and the surgical approach are discussed.

Abnormalities, Multiple↗