Objective: To evaluate the correlation of the capillary refilling time measured in neonates with the hemodynamic parameters obtained by Doppler echocardiography.
Design: Prospective study.
Setting: Neonatal intensive care unit (ICU) in a university hospital.
Patients: Neonates without congenital cardiac disease admitted to the neonatal ICU (n = 100).
Measurements and main results: The clinical parameters obtained were: heart rate; blood pressure; mean airway pressure; cutaneous temperature; and capillary refilling time. The echocardiographic data included the measurement of aortic diameter, left atrial diameter, and shortening fraction. Pulsed-Doppler echocardiography was used to measure flow velocity values in the ascending aorta, in the pulmonary artery trunk, and in the patent ductus arteriosus. Cardiac index was calculated secondarily from the volumetric equation, including measured flow velocity in the ascending aorta, aortic diameter, and body weight. Shunt severity at this level was measured by analysis of the descending aortic flow. Thereafter, three groups were defined for analysis: group 1 with obliterated ductus arteriosus; group 2 with patent ductus arteriosus without a retrograde flow in the subdiaphragmatic aorta; and group 3 with patent ductus arteriosus and a retrograde flow in the subdiaphragmatic aorta. There was no correlation between the capillary refilling time and the following parameters: shortening fraction; mean airway pressure; body weight; left atrial diameter/ aortic diameter ratio; blood pressure; and heart rate. In group 1, the capillary refilling time was significantly linked to cardiac index (r2 = .54, p < .001). A lower correlation coefficient between capillary refilling time and cardiac index was found in groups 2 (r2 =.31, p < .001) and 3 (r2 =.41, p < .001).
Conclusion: The capillary refilling time was significantly linked to cardiac index in neonates.