Cardiac surgery and neurological injury in children.
The freedom of children from vascular disease makes them an ideal population in which to study the deleterious effects of cardiopulmonary bypass. Cerebral embolic injury arises intraoperatively from air in the cardiac chambers and monitoring lines, particularly those in the left atrium. Postoperative emboli are more common in patients with single ventricle physiology, especially following a bidirectional Glenn shunt or Fontan procedure. Poor cannula selection or placement during bypass can cause maldistribution of the perfusate and cerebral injury. Postoperative hyperthermia can cause brain damage. Results of prospective and retrospective studies of neurological and developmental outcome after paediatric cardiac surgery at the Children's Hospital, Boston, have led to the following inferences: the use of circulatory arrest should be minimised; the pH stat strategy is preferred for cardiopulmonary bypass over the alpha stat strategy. A higher haematocrit on bypass, for example 30%, may be preferable to 20%; postoperative fever should be strenuously avoided. Surgeons should be aware that cardiopulmonary bypass parameters can have subtle but important effects on late developmental outcome.
Jonas
R A
RA
Children's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA. jonas_r@al.tch.harvard.edu