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Biomedical subjects

A D Chant

Publications and source records attributed to A D Chant.

At least 19 recordsLinked to original sources
PubMed1992

Effect of aprotinin on neutrophil function after major vascular surgery.

High-dose aprotinin reduces blood loss and blood transfusion requirements during liver transplantation and cardiac and vascular surgery. The mechanism of the haemostatic effect of aprotinin is unclear. A general effect on the anti-inflammatory response may be involved. Because leucocyte activation is part of this process, white cell function was measured in patients undergoing aortic surgery who received high-dose aprotinin therapy (n = 10) and was compared with the results from controls who did not (n = 10). The test group received an intravenous bolus (2 x 10(6) kallikrein inhibitor units) of aprotinin after induction of anaesthesia followed by continuous infusion (0.5 x 10(6) kallikrein inhibitor units/h) until the end of the operation. Blood samples were obtained before operation, immediately after surgery, and 1 and 7 days after operation. Aprotinin maintained significantly better postoperative white cell function as measured by bipolar shape formation (P less than 0.001), unstimulated nitroblue tetrazolium (NBT) reduction (P less than 0.001) and chemotaxis (P less than 0.001). Endotoxin-stimulated NBT reduction was similar in both groups, indicating that neutrophils from treated individuals retained the capacity to respond to oxidative stimuli. Aortic surgery activates neutrophils in vivo, as reflected by impaired chemotaxis and increased superoxide production. Aprotinin protects the cells against this potentially deleterious effect without affecting their ability to respond when provoked. Whether this affects leucocyte interaction with coagulation pathways and contributes to the reduction in blood loss remains to be determined.

Aged↗
PubMed1992

Non-invasive monitoring of cardiac output changes during aortic cross-clamping for infrarenal reconstruction--a new technique using suprasternal Doppler-derived cardiac output.

There is a significant morbidity and mortality associated with elective infrarenal aortic reconstruction. To examine the value of continuous cardiac output monitoring for predicting those at risk, 40 consecutive patients were monitored using Doppler-derived cardiac output. The anaesthetist was blind to all information from the monitor and managed the patients using standard techniques. In 28 patients there were no observed changes, while in seven, cardiac output rose after aortic cross-clamping. In five patients a fall in cardiac output occurred after cross-clamping. No cardiac events or cardiac deaths occurred in the 35 patients who showed a rise or no change in cardiac output. However, there were three cardiac events, including one cardiac death in the group of five patients in whom a fall in cardiac output was observed. It would appear that intraoperative non-invasive Doppler-derived cardiac output monitoring successfully predicts high-risk patients who would perhaps benefit from more intensive pre-, peri- and postoperative care.

Aged↗
PubMed1991

Designing a doctor.

Explore the source record for details and available documents.

Education, Medical, Undergraduate↗
PubMed1991

Non-invasive Doppler-derived cardiac output: a validation study comparing this technique with thermodilution and Fick methods.

The high mortality and morbidity related to cardiac events remains a considerable problem in vascular surgery. Predicting high risk patients is difficult except perhaps by coronary angiography which is invasive, costly and impractical. It would be useful to have a technique which could easily measure cardiac output and stratify cardiac risk in patients needing vascular surgery. Doppler-derived cardiac output may be such a technique. It offers considerable advantages over Swan-Ganz thermodilution measurement in that it is non-invasive, continuous, inexpensive, and requires only limited technical skill and training. In order to assess and validate a Doppler cardiac output monitor (ACCUCOM 2, Datascope Medical Co. Ltd.), we undertook a prospective study comparing Doppler-derived measurements with those obtained by thermodilution and Fick methods. Twelve patients undergoing elective coronary angiography were studied. Swan-Ganz thermodilution catheters were inserted on completion of cardiac catheterisation and five consecutive thermodilution and Doppler measurements made in each patient. Oxygen saturation from pulmonary artery and aortic blood samples, and a single indirect Fick cardiac output, were calculated. Linear regression analysis for Doppler against thermodilution gave a correlation co-efficient (r) of 0.81 (p less than 0.002), and (r) for Doppler against the Fick method was 0.76 (p less than 0.02). Bland and Altman's statistical method showed the differences to be normally distributed. The mean difference (thermodilution minus Doppler) was 0.32 l/min SD 0.48 l/min, 95% confidence limits -0.64 to +1.28 l/min. Doppler-derived cardiac output compares well with traditional methods of measurement and may be a useful tool in the assessment and monitoring of the high risk vascular patient.

Adult↗
PubMed1990

Impact of duplex scanning on carotid endarterectomy.

Duplex ultrasound permits safe and accurate assessment of the extracranial vasculature. This paper reports the change in patterns of referral to a specialized vascular unit following its introduction; increased referrals were seen in all specialties except neurology. A widely available and reliable duplex service has revealed more extracranial vascular disease than was previously recognized, and has increased referrals for carotid endarterectomy, thereby increasing surgical workload.

Adult↗
PubMed1990

Prospective randomised evaluation of a new cell saving device in elective aortic reconstruction.

In order to evaluate the clinical and haematological implications of salvage autotransfusion using the Haemolite device (Haemonetics, Leeds, UK), 67 aortic reconstructions were studied. Bank blood transfused during the operation fell from a median of four units in the control group to zero using the cell saver (P less than 0.0001), and wound drainage decreased from 250 to 200 ml (P = 0.12). Evidence of fibrinolytic and platelet activation was found during salvage, but no bleeding diathesis was encountered. There was no morbidity or mortality related to the technique, and median hospital stay was reduced in autotransfused patients. The Haemolite is a safe effective device for autotransfusion in elective aortic surgery, and can substantially reduce exposure of both patients and staff to the dangers of homologous blood.

Aorta, Abdominal↗
PubMed1990

Ventilatory effects of hypoxia and adenosine infusion in patients after bilateral carotid endarterectomy.

1. We have studied the carotid body contribution to hypoxic respiratory drive, using a hypoxic/hyperoxic switching technique, and the ventilatory response to intravenous infusion of adenosine, a recently described respiratory stimulant, in five patients with bilateral carotid endarterectomy. 2. The contribution made by the carotid bodies to total ventilatory drive during hypoxia varied from 2.5% to 45.9%. 3. The ventilatory response to adenosine infusion varied from a 7% decrease to a 25% increase in ventilation. 4. Those patients with intact hypoxic ventilatory drive showed respiratory stimulation, whereas of the two patients with attenuated chemoreflexes, one showed no stimulation and the other depression of ventilation in response to adenosine infusion. 5. We conclude that adenosine exerts its respiratory stimulant effect via an action on the peripheral chemoreceptors. This may coexist with a centrally mediated respiratory depression that is masked when the carotid bodies are intact.

Adenosine↗
PubMed1990

The Southampton teaching triad: an audit of operative surgical instruction.

Clinical audit and regular morbidity and mortality meetings are required of all units involved in surgical training. Agreed standards of training are under discussion in the face of new examinations and have not at present been formally evaluated. In order to quantify the level of operative surgery instruction in this unit, a prospective 'Teaching Audit' has been undertaken, using an extension of the existing surgical audit. Results, which are presented as a standardised diagram, reflect the relationship between trainer and trainee. Problems, such as missed teaching opportunities, were identified. The method can be applied to any specialty, and may be useful in planning teaching resources and surgical training programmes.

Breast↗