Changes in respiratory mechanics among infants undergoing heart surgery.
Children with excessive pulmonary blood flow (PBF) from congenital heart disease have abnormal respiratory mechanics. Exposure to hypothermic cardiopulmonary bypass (CPB) adversely affects lung function. We designed this study of 106 patients to determine the changes in respiratory mechanics in infants younger than 1 yr undergoing heart surgery. Dynamic respiratory compliance (Cdyn) and total respiratory resistance (Rrs) were measured before surgical incision, after sternal closure in the operating room, and after arrival in the intensive care unit. The following data were recorded: age, weight, preoperative pulmonary infiltrates, preoperative mechanical ventilation, evidence of increased PBF before surgery, duration of CPB, duration of aortic cross-clamp, duration of deep hypothermic circulatory arrest, use of steroids, and volume of ultrafiltrate removed. Repeated-measures analysis of variance with covariate analysis was used to determine the effect of each covariate on Cdyn and Rrs at the three time periods. Rrs improved after cardiac surgery correcting increases in PBF, and this was most pronounced in neonates. Among infants with normal or reduced PBF, cardiac surgery with CPB led to a reduction in Cdyn. We consider that the benefits of surgical correction of pulmonary overcirculation outweigh the negative effects of CPB on respiratory mechanics.


CONCLUSIONS
The benefits of surgical correction of pulmonary overcirculation outweigh the negative effects of cardiopulmonary bypass on respiratory mechanics in infants.
Stayer
Stephen A
SA
Departments of *Anesthesiology, †Pediatrics, and ¶Surgery, Divisions of ‡Pediatric Cardiovascular Anesthesiology and §Congenital Heart Surgery, Baylor College of Medicine, ∥Texas Children's Hospital, Houston, Texas.
Diaz
Laura K
LK
East
Debora L
DL
Gouvion
Jill N
JN
Vencill
Tracie L
TL
McKenzie
E Dean
ED
Fraser
Charles D
CD
Andropoulos
Dean B
DB
D000375:Aging / Q000502:physiology; D000403:Airway Resistance / Q000502:physiology; D001784:Blood Gas Analysis; D006348:Cardiac Surgical Procedures; D002315:Cardiopulmonary Bypass; D003250:Constriction; D005260:Female; D006324:Heart Arrest, Induced; D006801:Humans; D007223:Infant; D008170:Lung Compliance / Q000502:physiology; D008297:Male; D011652:Pulmonary Circulation / Q000502:physiology; D012129:Respiratory Function Tests; D015656:Respiratory Mechanics / Q000502:physiology*; D013256:Steroids / Q000627:therapeutic use
D013256:Steroids