Study of central hemodynamic parameters in pediatric burn shock patients using the method of the heart cycle phase analysis

Aims This paper deals with a study of central hemodynamics in 363 pediatric patients with burn shock as compared with a reference healthy children group in order to establish clinical value of the hemodynamic parameters for burn shock diagnostics and therapy. Materials and methods There is a new method applied to examine the functional status of the cardiovascular system with use of the medical equipment Cardiocode that is based on the method of the heart cycle phase analysis and capable of measuring parameters such as a stroke volume (SV), a circulation minute volume (CMV), systolic parameters (both a rapid ejection volume Vr.e. and a slow ejection volume Vs.e.), diastolic parameters (an early diastole volume Ve.d. and an atrial systole volume Va.s.), including a volumetric parameter characterizing the actual tonus of the ascending aorta (Va.а.). Results Age-related trends in the above volumetric parameters have been established herein. Specific features of the hemodynamic parameters in pediatric patients with burn shock have been identified. Conclusion Diagnostics of changes in the central hemodynamics in pediatric burn patients at their hospital admission provides reliable prediction tools for detecting shock well in advance and starting with an adequate intensive therapy. Keywords Pediatric patients ≈ Burn shock ≈ Hemodynamics ≈ Stroke volume ≈ Minute volume ≈ Cardiac output ≈ Cardiocode ≈ Heart cycle phase analysis Imprint Vladimir A. Vecherkin, Victor A. Ptitsin, Olga K. Voronova. Study of central hemodynamic parameters in pediatric burn shock patients using the method of the heart cycle phase analysis; Cardiometry; No.1; November 2012; p.48-56; doi:10.12710/cardiometry.2012.1.4856 Available from:

Treatment of children with thermal burns complicated by a shock is a very critical issue in pediatrics surgery. Even with use of most advanced technologies in treatment of severely burned pediatric patients, sometimes we have to deal with rather significant mortality and disability rates [1]. The clinical studies show the presence of considerable disturbances in the central hemodynamics and oxygen supply to tissues in the above shock-trauma patients [2,3,4]. Therefore, our study of the central hemodynamic parameters conducted in the said patient population should be of great interest to pediatricians and pediatric surgeons.

Until the present time, there has been no complete picture for perfect understanding of laws of the performance of the heart and its associated blood vessels. This is because one of the open issues in blood circulation physiology is to properly realize the fluid mechanics of the cardiovascular system as a single system and, on this basis, acquire knowledge of its design and management laws [5]. The blood flow system is a giant hierarchical structure integrating a great number of systems and subsystems with some common and specific features, the functioning of which is aimed at one thing only: to maintain an adequate blood flow in all organs and tissues in our organism according to the principle of biological optimization making every biological system as efficient as possible.

At present, the condition of the pumping function of the heart is assessed according to some conventional significant parameters of the central hemodynamics, among which are the stroke volume, the minute volume that is known as the cardiac output (CO) and the total peripheral resistance that is referred to as the systemic vascular resistance (SVR). Both the stroke volume (SV) and the circulation minute volume (CMV, or CO) are measured by direct (invasive) or indirect (noninvasive) methods while the SVR is calculated from the fluid dynamics Poiseuille’s equation. As a rule, for measuring of SV and CMV parameters in pediatric practice used are noninvasive methods [6]. It is generally believed that both conventional invasive and noninvasive methods for measuring central hemodynamic parameters are based on assumptions that blood plasma and formed elements circulate with the same velocity. But new evidence demonstrates [7,8,9,10] that erythrocytes move in the pulsating blood flow due to static pressure gradients, generated transverse to the blood vessel axis, forming in such a manner a specific dynamic radial ring pattern, that facilitates the much more faster movement of the erythrocytes as compared with plasma.

At the same time, it should be noted that there is no rigorous relationship between the stroke volume and the systemic vascular resistance. The reason is that it is customary to assume that the blood circulation in our organism is maintained in a flow mode according to the Poiseuille’s law. But this assumption is inconsistent with the principle of optimization in biological systems according to which all processes in the biological systems are managed in the most perfect manner (to maximize their efficiency).

Over forty years ago, it was established that blood circulation is managed not under the Poiseuille’s law, but by meeting the most efficient “third-type” flow conditions [9, 10]. This innovative blood flow concept laid the foundations for development of a new noninvasive method for measuring parameters of the central hemodynamics that was based on actual times of every heart cycle phase, and it is just the method that is used in our study described herein (i.e., the method by Poyedintsev – Voronova) [8,9].

The study of the central hemodynamic parameters in pediatric patients with burn shock was aimed at establishing clinical value of the said parameters.

Materials and methods

97 healthy patients aged 1 to 14 years from preschool and school institutions as reference groups were studied by us. In the pediatric clinics, 363 children with burn shock were enrolled into the study of the central hemodynamic parameters using the medical equipment Cardiocode (produced by the Scientific-Technical Company CARCDIOCODE, Taganrog, Russia). At the hospital admission, in pediatric patients the standard parameters of hemodynamics were taken as follows: HR, AP, CVD, Hb, Ht complete with their ECGs. With use of Cardiocode, by the Poyedintsev – Voronova method, we measured the following heart performance data:

SV (ml) – stroke volume;

CMV (l) - circulation minute volume, or cardiac output;

Ve.d. (ml) is a volume of blood entering the left ventricle in the slow filling phase due to venous inflow and suction function of the ventricle (early diastole);

Va.s. (ml) is a volume of blood, entering the left ventricle in the atrial systole that features the left atrium myocardial contractility, and, in addition, phase-related diastolic volumetric parameters Ve.d. and Va.s. featuring the preload level;

• Vr.e.(ml) is a volume of blood ejected by the left ventricle in the rapid ejection phase;

• Vs.e.(ml) is a volume of blood ejected by the left ventricle in the slow ejection phase;

the systolic phase-related volumetric parameters Vr.e. and Vs.e. are strong markers of the myocardial contractility of the left ventricle;

Va.а. (ml) is a volume of blood pumped by the ascending aorta as peristaltic pump (in the phase of slow ejection), reducing by this means the post-load of the left ventricle. Besides, this volume is a strong marker of the ascending aorta tonus.

The measurements of the central hemodynamic variables in burn-shock patients were performed with Cardiocode according to the schedule as follows: on hospital day 1, day 2, day 5, day 10, day 20, and day 45 post-burn.

It should be noted that the results obtained therein are assessed not only in absolute units of measure but also by evaluating the deviations of the hemodynamic parameters from their top and bottom limits, considering heart rate (HR), sex and age of every child.

The statistics was processed with application of the Software STATISTICA employing both parametric and non-parametric criteria.

To test the hypothesis of difference in sample means, the paired two sample Student’s t-Test is applied by us. In this case, it is assumed that there are unequal dispersions of the general populations from which our samples are drawn. The paired t-Test is usually conducted when natural pairs of observations in sampling occur, for example, when a general population is tested two times.

For all surveys, representativeness of the obtained results is assessed.

In testing the statistics hypotheses, it is assumed that p-values <0,05 to <0,001 are statistically significant.

A correlation analysis is carried out to determine the probability that the correlation is a real one and not a chance. This analysis makes possible to sample matters, which have the most significant influence on the resulting attribute, and identify previously unknown relationships between variables. It should be employed for quantitative assessment of cross-relations between two data sets represented dimensionless. Following this way, the sample correlation coefficient is the covariance of two data sets that is obtained by dividing by the product of their standard deviations.

Results and discussion

The parameters of the central hemodynamics (CH) were studied by us first in three reference groups of healthy children: group 1– infants and children aged 1 to 4 years, group 2 – children aged 4 to 7 years, and group 3 – children aged 7 to 14 years (s. Table 1 below).

Phase-related volumetric parameters of CH in healthy children.

Table 1. Phase-related volumetric parameters of central hemodynamics in healthy children.