Measurement of Cardiac Output in Children. In: Vincent J, editor. Yearbook of Intensive Care and Emergency Medicine. Berlin: Springer Berlin Heidelberg; 1995. pp. 606-14. [DOI: 10.1007/978-3-642-79154-3_49]

Cardiac output and blood volume parameters using femoral arterial thermodilution

BACKGROUND

The pulse-induced continuous cardiac output (PiCCO) system is a less invasive method than pulmonary thermodilution for the measurement of cardiac output and estimating blood volume parameters. The normal values in children have not been defined. The purpose of the present paper was therefore to evaluate cardiac output and parameters of blood volume using femoral arterial thermodilution in critically ill children.

METHODS

A prospective study was performed in 17 critically ill children aged between 2 months and 14 years. Two measurements were taken for each determination of cardiac output, global end diastolic volume (GEDVI), intrathoracic blood volume index (ITBI), extravascular lung water index (ELWI), systolic volume index (SVI), stroke volume variation (SVV), cardiac function index (CFI), left ventricular contractility (dp/dt max), and the systemic vascular resistance index (SVRI).

RESULTS

One hundred and seventeen measurements were performed. The mean cardiac index (CI) was 3.5 +/- 1.3 L/min per m(2). The GEDVI (399.7 +/- 349.1 mL/m(2)), ITBI (574.5 +/- 212.2 mL/m(2)) and dp/dt max (804.6 +/- 372.1 mmHg/s) were lower than reported in adults, whereas ELWI (18.9 +/- 9.3 mL/m2) and CFI (8 +/- 2.5 L/min) where higher. The GEDVI, SVI, dp/dt max and CI increased with the weight of the patients whereas the ELWI values decreased.

CONCLUSIONS

Femoral arterial thermodilution is a suitable technique for the measurement of cardiac output in critically ill children. The intrathoracic and intracardiac volumes are lower than in adults, whereas extrapulmonary water is higher; these values are related to the weight of the patient.

Estimation of the parameters of cardiac function and of blood volume by arterial thermodilution in an infant animal model

BACKGROUND

Experimental studies in adults and in animals have reported that estimation of the intracardiac volumes by arterial thermodilution is a more reliable method of blood volume estimation than pressure measurement. The objective of this study has been to analyze the values of cardiac function and blood volume in an infant animal model using the arterial thermodilution technique.

METHODS

A total of 202 measurements of cardiac output were performed by femoral arterial thermodilution in 38 Maryland piglets weighing between 8 and 16 kg, to determine the normal values of blood volume obtained by arterial thermodilution (PiCCO method) in an infant animal model. The following parameters were measured: blood volume [global end-diastolic volume index (GEDVI), total intrathoracic blood index (ITBI), extravascular lung water index (ELWI), systolic volume index (SVI)] and parameters of cardiac and vascular function [systolic volume index (SVI), cardiac function index (CFI), left ventricular contractility (Dp/dtmax), and systemic vascular resistance index) (SVRI)].

RESULTS

The cardiac index, 4.3 +/- 1.2 l x min(-1) x m(2), was within the normal range. The GEDVI, 198 +/- 48.6 ml x m(2), and ITBI, 574.1 +/- 113.4 ml x m(2), were lower than the normal values reported in adults, whereas the ELWI, 16.3 +/- 5.2 ml x kg(-1), was higher.

CONCLUSIONS

Intrathoracic and intracardiac volume values obtained by arterial thermodilution are lower than those considered normal in the adult, whereas the extravascular lung water is higher. These values must be taken into account when the PiCCO method is used in small children.

Correlation between Cardiac Output Measured by the Femoral Arterial Thermodilution Technique Pulmonary Arterial and that Measured by Contour Pulse Analysis in a paediatric animal model

OBJECTIVE

To evaluate the correlation between two methods for the determination of cardiac output: the femoral arterial thermodilution technique (FATD) and the arterial pulse contour analysis (PCCO) using the PiCCO catheter.

METHODS

We performed a prospective animal study using 51 immature Maryland pigs weighing 9 to 16 kg. A 4- or 5-Fr arterial PiCCO catheter was introduced into the femoral artery. In each animal, we made measurements of cardiac output at 30-minute intervals by femoral arterial thermodilution for a total of 209 measurements. We registered the previous PCCO and compared with the mean of two measures of FATD cardiac output.

RESULTS

Mean FATD was 1.73 +/- 0.60 L/min and mean PCCO was 1.78 +/- 0.70 L/min (no significant difference). The mean difference (bias) of differences (limits of agreement) was 0.04. The correlation founded between the two methods was 0.786 (95% confidence interval, 0.71-0.83).

CONCLUSIONS

Femoral arterial thermodilution cardiac output measurements correlates well with pulse contour analysis cardiac output in this paediatric animal model.