PERIOPERATIVE RESPIRATORY COMPLIANCE IN CHILDREN UNDERGOING REPAIR OF ATRIAL SEPTAL-DEFECTS

Children with atrial septal defects (ASD) have less respiratory compliance (Crs) than normal cohorts. There could be implications for anaesthetic management if these children also have decreased compliance during anaesthesia. To examine the changes in Crs before, during and following surgical correction of the atrial defect, Crs was measured in 29 infants and children, 15 undergoing correction of secundum type atrial septal defects, and a group of 14 children of similar weight undergoing non-thoracic surgery. During sedation, Crs was measured using the single breath technique (SBT) and during anaesthesia, both before and after the surgical procedure, an inflation technique was applied to determine Crs. To investigate the aetiology of the difference in Crs, the pulmonary to systemic flow ratio (Qp:Qs) was determined using echocardiography during sedation in the ASD patients. During sedation, Crs in the ASD group was 52.7 +/- 19.5% less than in the control group. The slope of the line of regression of Crs vs height for the ASD group was significantly less (P < 0.05) than that of the control group during sedation. However, during anaesthesia, Crs in the ASD group was not significantly different from the control group either before or after surgery. The per cent decrease in Crs during sedation in the children with ASD, in comparison with the control group, did not correlate with the Qp:Qs ratio of the ASD group (r2 = 0.012, NS). We conclude that, in spite of lower Crs during sedation, infants and children with ASD do not have lower Crs during anaesthesia and cardiopulmonary bypass than normal controls undergoing non-thoracic surgery. The decrease in Crs in the children with ASD during sedation is not related to their Qp:Qs.