Assessment of cardiac function in infants with transposition of the great arteries after surgery: comparison of two methods.

Background: Assessment of cardiac function is crucial in pediatric patients undergoing cardiovascular surgery, monitoring cardiac output and changing hemodynamic conditions during surgery accordingly is important to improve post-surgical outcome. We aimed to measure cardiac index (CI) and maximal rate of the increase of left ventricular pressure dp/dt(max) with the pressure recording analytic method (PRAM, MostCare) and compared it with transthoracic echocardiographic cardiac index estimation in infants with transposition of the great arteries (TGA) undergoing surgical correction.

Methods: We enrolled 74 infants with TGA consecutively into this study. CI and dp/dt(max) were measured with PRAM and echocardiography at 0, 4, 8, 12, 24 and 48 h postoperatively. Blood brain natriuretic peptide (BNP) and blood lactate (Lac) were measured at baseline and after operation.

Results: The median age at surgery was 13 days (range 1-25 days) with an average weight of 3.24 kg (range 2.31-4.17 kg). CI estimated by PRAM was 1.11 ± 0.12 L/min/m (range 0.69-1.36) and by Doppler echocardiography was 1.13 ± 0.13 L/min/m (range 0.76-1.40). dp/dt(max) estimated by PRAM was 1.31 ± 0.03 mmHg/s (range 1.23-1.43) and by Doppler echocardiography was 1.31 ± 0.04 L/min/m (range 1.25-1.47). CI (r = 0.817, P < 0.001) and dp/dt(max) (r = 0.794, P < 0.001) measured by two methods were highly correlated with a linear relation. Blood BNP and lactate increased to the highest level at 8-12 h post-operatively.

Conclusions: In the early post-operative period, PRAM provides reliable estimates of cardiac index and dp/dt(max) value compared with echocardiographic measurements. PRAM through mostcare is a reliable continuous monitoring method for peri-operative management in children with congenital heart disease.