1996 OPEN FORUM Abstracts
ASSESSMENT OF RADIOLOGIC AND HEMATOLOGIC INDICATORS FOLLOWING ECLS CIRCUIT CHANGES
Lynne K. Bower RRT, Dario O. Fauza M.D., R Cleveland M.D., Mae Jacobson, Jay M. Wilson M.D. Children's Hospital, Boston, MA
INTRODUCTION: Circuit changes are sometimes necessary during extended extracorporeal life support (ECLS) runs. It has generally been assumed that these circuit changes result in a deterioration in the patient's respiratory status. This assumption is based on the opacification of the chest x-ray and worsening of lung compliance encountered after the initiation of ECLS, a change attributed to inflammatory response from interaction of blood with bioactive surfaces of the ECLS circuit. In order to prospectively evaluate whether subsequent circuit changes (CC) are also associated with a similar deterioration, we prospectively evaluated the impact that changing the ECLS circuit has on certain complement levels (C3A and C5A), coagulation factors, lung compliance (Cdyn), and appearance of the chest x-ray (CXR). Methods: Coagulation factors, hematocrit, ACTs, platelet consumption, heparin requirement, and Cdyn were recorded 24 hours before and 24 hours after each CC. C3A and C5A levels were drawn prior to and at 3, 12 and 24 hours following circuit change. The CXR was blinded and both subjectively and objectively evaluated 12 hours prior to and 24 hours after CC. Objective assessments were made by serial comparative measurements of lung field/air density ratio through an X-Rite model 301 light densitometer. Statistical analysis was by ANOVA and the Scheffe F test, with significance set at 0.05. Results: Twelve circuit changes were performed in eight patients due to either excessive circuit clots or coagulopathy. Platelet count significantly increased following CC (p=.01). Fibrinogin levels also rose but not significantly. Hct, PT, ACT and heparin requirement did not change. By both subjective and objective evaluation, the CXRs did not change significantly after CC. Cdyn was also not affected by the circuit change. C3A and C5A levels were not significantly different either, however, C3A was elevated both prior to and after CC. CONCLUSION: From this preliminary data we conclude that circuit changes during the course of ECLS do not appear to adversely affect the patient's hematologic or respiratory status. Therefore, decisions regarding circuit changes should be made based on the condition of the circuit and not the patient.