Elevated cerebral perfusion pressure and low colloid osmotic pressure as arisk factor for subdural space-occupying hygromas?

BACKGROUND Space-occupying subdural hygromas are a late complication of severe traumat ic brain injury (TBI) and may delay the patient's recovery. To evaluate the risk factors involved, we performed a semiretrospective, -prospective anal ysis of three groups of patients, which differed with regard to the techniq ues used in the management of their cerebral perfusion pressure (CPP) and c olloid osmotic pressure (COP) to determine the occurrence of space-occupyin g subdural hygromas. PATIENTS AND METHODS Between 1989 and 1997 we examined 696 patients after a severe TBI: Group 1. 1989-1994 mean CPP: 67 (elevated for therapeutic reasons by catech olamines, if necessary), mean COP: 19. Group 2. January 1995-October 1996, mean CPP: 77, mean COP: 20. Group 3. November 1996-December 1997, mean CPP: 79, mean COP: 23 (elevated for therapeutic reasons by infusions of colloids). The groups were comparab le for other criteria. RESULTS Compared to Group 1, Group 2, with a high CPP but lower COP, showed a signi ficantly higher (p < 0.01; chi(2)-test with correction of Yates) percentage of posttraumatic subdural hygromas with space-occupying aspects, clinical signs of bradycardia, hypertension and impaired consciousness requiring sur gery (Group 1: 1.75%; Group 2. 10.46%; Group 3. 0%). In Group 3 we saw no p atient with a space-occupying hygroma. CONCLUSION We conclude that iatrogenic elevated CPP, which has been reported to be hel pful in preventing secondary ischemic damage after a severe TBI, may be har mful to a patient if the COP is not maintained within physiological ranges. (C) 1999 by Elsevier Science Inc.