Search

At present there is no satisfactory technique for repeated lung biopsy in recipients of heart-lung transplants. A new technique for lung biopsy, which might be adopted for this purpose, has been developed. A Teflon sheath is inserted through the jugular vein into the pulmonary artery with the aid of a balloon catheter. A flexible biopsy forceps is then introduced through the sheath into the pulmonary arterial tree and advanced into the periphery of the lung, where biopsy samples are taken. The procedure was attempted in 14 pigs. Initially crocodile jaw (two pigs) and fenestrated cups forceps (five pigs), which are currently in use for transbronchial lung biopsy, were used. Subsequently the biopsy forceps was modified and the jaws were replaced by a cutting needle mechanism (six pigs). Out of the 13 animals in which the procedure was technically possible, lung parenchyma was obtained from nine and pulmonary arterial wall from 11. One animal died shortly after the procedure. The cause of death could not be determined with certainty at postmortem examination. There was, however, a small tear on the surface of the lung, which could have produced a tension pneumothorax. The other 12 animals recovered from the procedure. They were killed 24 hours later and postmortem examination was carried out. One animal in which the crocodile jaw forceps had been used had a haematoma in the lower lobe (3 X 3 X 4 cm) and 100 ml of blood in the pleural cavity. In the other 11 animals, in which the fenestrated cups or the cutting needle forceps had been used, the intrapulmonary haematomas were 1-2 cm in diameter and the pleural surface was intact. It is concluded therefore that transvenous lung biopsy is feasible and that this procedure might find an application in monitoring rejection in recipients of heart-lung transplants.

Rapid uniform cooling of the heart is the most important requirement of any method using local hypothermia for protection of the myocardium during open intracardiac surgery. We report the construction and operation of a recirculation cooling circuit comprising a reservoir, pump, and heat-exchanger for this purpose. It is operated by the perfusionist and can deliver up to 1 litre of fluid per minute at 4 degrees C into the pericardium or interior of the heart. Advantages of the system include rapid cooling of the myocardium, simplicity of operation, and applicability to all routine cardiac surgical procedures.

A raised hemidiaphragm has been reported as an uncommon complication of cardiopulmonary bypass, possibly resulting from cold injury to the phrenic nerve. At Papworth Hospital myocardial protection during cardiac arrest relies in part on irrigation of the pericardial cavity with large volumes of Hartmann's solution at 4 degrees C. Retrospective review of the chest radiographs of 100 consecutive patients undergoing cardiopulmonary bypass showed that 31 had a raised left hemidiaphragm soon after operation. The only significant correlation was with aortic cross clamp time (p less than 0.03). A prospective study of 36 consecutive patients undergoing cardiopulmonary bypass was then undertaken with diaphragmatic screening and chest radiography. Preoperative screening gave normal results in all patients. In the early postoperative period 16 (44%) had left diaphragmatic weakness or paralysis, two (5.5%) right sided weakness, and two (5.5%) bilateral weakness. Repeat screening of these patients showed resolution in all but four cases (80%) at six months and in all but two (90%) at one year. The greater number of left sided lesions than of right (8:1) is probably due to the fact that the cold jet of irrigating fluid is directed towards the left phrenic nerve. These findings have implications with regard to the optimum temperature of the irrigant fluid for myocardial protection during cardiopulmonary bypass.

Over a three year period we have used haemodialysis and haemofiltration in parallel with cardiopulmonary bypass in 26 patients. Impaired renal function and excessive fluid retention have been the main indications. Patients on haemodialysis programmes for end stage renal failure did not require further dialysis until at least the third postoperative day, when they could tolerate the haemodynamic disturbance of dialysis. In the other patients these techniques proved valuable in reversing the effects of haemodilution and in controlling the concentration of serum potassium. Our experience has confirmed that haemodialysis and haemofiltration in parallel with cardiopulmonary bypass are useful adjuncts in the perioperative management of patients with impaired renal function undergoing open heart surgery. The techniques are also effective in correcting the fluid retention and biochemical imbalance in patients with congestive cardiac failure, including those with heart transplants.