Delayed sternal closure is used to prevent low cardiac output syndrome in selected newborns shortly after cardiac surgery for congenital cardiac defects. Sternal closure itself often causes haemodynamic and ventilatory instability that cannot be entirely assessed by standard monitoring means. Therefore, we used transpulmonary thermodilution technique for an exact evaluation of the haemodynamic changes.

Between April, 2006, and December, 2008, 23 neonates aged from 1 to 30 days, with a median of 7 days, and weighing from 1.9 to 4.2 kilograms, with a median of 3.25 kilograms, were studied after biventricular corrections. Residual intracardiac shunts were excluded by echocardiography. Haemodynamic and ventilatory parameters, along with those obtained by the transpulmonary thermodilution technique, were recorded before and immediately after the sternal closure, and then at 0.5, 1, 2, 6, 12, 24, and 48 hours.

Chest closure caused significant decrease in systolic arterial pressure from 80.04 ± 11.48 to 69.48 ± 9.63 mmHg (p < 0.001), cardiac index from [median (25th/75th centile)] 2.640 (2.355/2.950) to 2.070 (1.860/2.420) l/min/m2 (p < 0.001), stroke volume index from 18.50 (16.00/20.00) to 14.00 (11.00/17.00) ml/m2 (p < 0.001), and dynamic lung compliance from 2.45 (2.31/3.00) to 2.30 (2.14/2.77) ml/cmH2O (p = 0.007). Stroke volume variation increased from 14.00 (9.25/16.75) to 18.00 (15.00/21.00) % (p < 0.001). The oxygenation index transitorily increased from 2.50 (2.14/3.15) to 3.36 (2.63/4.29) (p < 0.001). Serum lactate decreased from 1.40 (1.12/2.27) to 1.0 (0.8/1.3)mmol/l, p < 0.001 in coincidence with a haemodynamic stabilisation at a later time after chest closure. Cardiopulmonary instability caused by the sternal closure necessitated therapeutic intervention in 18 of 23 patients (78.3%).

Delayed sternal closure causes a significant transitory decrease in stroke volume, cardiac output and arterial blood pressure. Also lung compliance and blood oxygenation are temporarily significantly compromised.

Continuous monitoring of cardiac output during liver transplantation is essential to evaluate the patient’s haemodynamic tolerance to acute volume variations. The aim of this study was to compare the cardiac output values obtained with a transoesophageal echo-Doppler and those obtained with a continuous thermodilution cardiac output pulmonary artery catheter.

Twenty adult patients were prospectively studied during a 5 min hepatic vascular exclusion test performed at the end of the dissection phase. Echo-Doppler and continuous thermodilution cardiac output, mean arterial pressure and end-tidal CO2 were measured before and at the end of the test.

Before the test, echo-Doppler cardiac output was 7.0 ± 2.7 L min−1 and thermodilution was 9.4 ± 3.1 L min−1, (R = 0.85, P < 0.001). The end test values were, respectively, 3.5 ± 2.7 and 7.8 ± 3.5 L min−1 (R = 0.23, P = 0.34). Bland and Altman analysis showed a bias of −2.2 before the test, which increased to −4.4 at the end of the test. Mean arterial pressure decreased from 85.5 ± 15 to 66.8 ± 16 mmHg, end-tidal CO2 from 31.4 ± 2.3 to 23.8 ± 2.7 mmHg.

Echo-Doppler cardiac output values are different from those measured by thermodilution cardiac output in these patients. Echo-Doppler cardiac output monitoring seems to detect the output changes, which can occur during acute haemodynamic changes more rapidly than thermodilution cardiac output in the course of liver transplantation.

Intraoperative Doppler ultrasound can be used to measure cardiac output by transoesophageal echocardiography. Recently, its reliability, when compared to the thermodilution technique, has been questioned. The purpose of this study was to compare intraoperative changes in cardiac output measured by echo-Doppler and by thermodilution in cardiac surgery. We also assessed the agreement between the techniques.

Fifty cardiac surgical patients (38 male, 12 female, mean age of 63.4 ± 14.3 yr) were prospectively included after approval by the Ethics Committee of the Institution. Cardiac output was assessed by thermodilution, with 10 mL saline at 12°C, and simultaneously and blindly by echo-Doppler in deep transgastric view with pulsed wave Doppler at the level of the left ventricular outflow tract. Matched thermodilution cardiac output and echo-Doppler cardiac output measurements were taken three times at the end of expiration, both pre- and post-cardiopulmonary bypass.

Echo-Doppler measurements were obtained in 44 patients (88%). In three patients, Doppler recordings could not be obtained adequately, and three developed left ventricular outflow tract obstruction after bypass. Bland–Altman analysis revealed a bias of 0.015 L min−1, with narrow limits of agreement (−1.21 to 1.22 L min−1) and 29.1% error. Echo-Doppler was accurate (92% sensitivity and 71% specificity, P = 0.008 by receiver operating characteristic curves) for detecting more than 10% of change in thermodilution cardiac output. There were no complications related to the study.

The agreement between cardiac output by echo-Doppler and by thermodilution is clinically acceptable and transoesophageal echocardiography is a reliable tool to assess significant cardiac output changes in a population of selected patients.

The aim of this study was to compare cardiac output measurements of the non-invasive cardiac output and the pulmonary artery catheter during repeat surgery for hip replacement.

In this prospective observational study, patients undergoing repeat hip surgery who needed a pulmonary artery catheter were included. A standard protocol was followed for induction, endotracheal intubation and maintenance of anaesthesia (sufentanil, etomidate, sevoflurane, cisatracurium). After endotracheal intubation, the non-invasive cardiac output was connected and a pulmonary artery catheter was inserted. Data were collected every 3 min until patients were extubated.

Ten patients were included and 2455 points of comparison recorded. Cardiac output from the pulmonary artery catheter varied from 1.7 to 8.9 L min−1 (mean 4.1 L min−1) and the non-invasive cardiac output (using averaging mode) from 1.7 to 8.0 L min−1 (mean 3.7 L min−1). There was a significant correlation between them (P < 0.01; bias 0.3 L min−1; limits of agreement +1.9 and –2.5 L min−1), although these differed between patients.

The perioperative bias was small and the non-invasive cardiac output slightly underestimated cardiac output intraoperatively compared to the pulmonary artery catheter. The bias was smaller when mean cardiac output was below 3 L min−1. Core temperature between 34.4°C and 37.6°C had no influence on the differences.