Evaluation of Hemodynamics in Infants and Small Babies after Open Heart Surgery

Summary

The study was undertaken to establish typical hemodynamic changes and reliable clinical tests for the evaluation of these in infants after open heart surgery.

The cardiac index was measured using the thermodilution technique in 56 infants. The age of the patients varied from 6 to 28 months and body weight from 4 to 15kg. All studies were done during the first 24 hours after operation.

lt was shown that in a hemodynamically smooth postoperative course cardiac index exceeds 2.7 l·min^-1·m^-2, toe temperature (normal 32° to 34°C) and rectal-skin temperature gradient (normal 2° to 3°C) are normalized within 6 to 9 hours postoperatively.

In case of low cardiac output syndrome, the cardiac index was below 2.5 l · min^-1·m^-2, toe temperature was lowered to 26° to 28° C and the rectal-skin temperature gradient was 8° to 10° C.

Big toe skin temperature correlated well with the magnitude of the cardiac index (r = 0.80; n = 247; p < 0.001); stroke index (r = 0.70; n = 247; p < 0.001); systemic vascular resistance (r = 0.64; n = 247; p < 0.001) and urine output (r = 0.74; n = 247; p < 0.001).

The results obtained indicated that, for the evaluation of hemodynamics in infants immediately following open heart surgery, it is mandatory to measure the cardiac index and central and peripheral (skin) temperatures, because the cardiac index in the first 6 postoperative hours and the rate of normalization of skin temperature are the most significant variables for the prognosis of postoperative hemodynamic recovery.

Key words

Infant open heart surgery - Cardiac output - Postoperative course - Thermometry