The need for artificial hearts.

Chronic immunosuppression, allograft coronary disease, and restricted availability of donor organs continue to limit the scope of cardiac transplantation. Meanwhile increasingly favourable experience with implantable blood pumps used as a bridge to transplant has reintroduced the concept of permanent mechanical cardiac support. Existing models (for example, the Thermo Cardiosystems Heartmate device) are now used for such support in patients who are not candidates for transplantation. Miniaturised axial flow pumps such as the Jarvik 2000 fit within the failed left ventricle and provide an exciting prospect for the treatment of heart failure in the future. Preliminary experience suggests that the "offloaded" left ventricle may recover. Mechanical blood pumps can be used before the onset of multisystem failure and removed if the myocardium recovers. This "bridge to recovery" concept should be tested in patients with recoverable cardiomyopathy and those with coronary disease and poor left ventricular function where an implantable pump can be used in conjunction with myocardial revascularisation.

Platelet responses to cardiopulmonary bypass. Assessment by a shear stress activation technique.

Platelet responses before and during cardiopulmonary bypass were studied using a shear stress activation technique. Whole blood was passed through a 10 microns micro-porous filter and the percentage of platelets retained was determined. Retention in control subjects (n = 20, age 62 +/- 11 years) was 65.2 +/- 15.1%. Patients with ischaemic heart disease (n = 20, age 61 +/- 9 years) had significantly higher retention at 82.6 +/- 13.2%, p less than 0.001. In valvular heart disease (n = 15, age 57 +/- 14 years) the retention rate was 43.5 +/- 15.4%, lower than both controls and ischaemic heart disease patients (p less than 0.001). In vitro haemodilution had no significant effect on platelet retention. High retention rates were maintained in patients undergoing coronary artery surgery. During valve surgery retention increased before aortic cross-clamp removal (83.5 +/- 13.4%) compared with baseline values (p less than 0.001) and remained high 24 hours postoperatively (79.6 +/- 9.4%). Platelet retention also increased within 20 minutes of thoracotomy without cardiopulmonary bypass (n = 10, age 57 +/- 8 years, 79.3 +/- 11.6% versus 61.6 +/- 10.9% baseline, p less than 0.01) and remained high 24 hours postoperatively. Significant differences in platelet responses, assessed by shear stress activation, were demonstrated between healthy controls and patients with ischaemic and valvular heart disease. Surgery, with or without extracorporeal circulation, caused a significant increase in platelet retention.

Trauma centres and the efficient use of financial resources.

The economic aspects of trauma centres were examined using published results and local financial data to discover if such institutions are an efficient use of resources. The cost of trauma centre care depends upon the number of centres built. An 'ideal' system in the UK of eight centres will cost 31.268 pounds per life saved compared with 45.661 pounds for the system proposed by the Royal College of Surgeons of England. Trauma centre care will be expensive but will generate benefits in return. Survivors will be young (mean age 30 years) and most (70-80 per cent) will regain their pre-injury functional/work status. When considered in terms of Quality Adjusted Life Years (QUALYs), trauma centres are a relatively efficient use of resources. An expected cost per QUALY of 942-1376 pounds is inexpensive compared with many health pursuits currently funded within the UK National Health Service.

Assessment of generalised airway obstruction in patients with carcinoma of the bronchus.

50 patients with carcinoma of the bronchus were studied during their pre-operative assessment for lung surgery. Lung function test indications of generalised airway obstruction agreed closely with clinical evidence of chronic bronchitis. These findings support the suggestion that the shape of the FVC tracing and the maximal expiratory flow-volume curve can be used to distinguish between the presence of generalised airway obstruction due to chronic bronchitis and of localised obstruction due to the tumour alone. The effectiveness of a method of predicting the risk of cardiopulmonary complications after lung surgery based upon pre-operative lung function test results is demonstrated.