The impact of an increase in the extracellular space volume on the circulatory system in patients with severe sepsis, compensated by liquid resuscitation and dopaminergic support

Abstract

Topicality. At the beginning of the 21^st century sepsis remains one of the most urgent problems in medicine. The sickness rate increases annually without  mortality rate decreasing.

Objective. In case of compensated sepsis-induced hypotension to create hemodynamic plateau using the figures of the average arterial pressure and minute volume of blood circulation; to explore the effect of increasing the volume of extracellular space on cardiac and hemodynamic indices.

 Material and methods. The study involved the patients with purulent septic complications (mainly surgery or abdominal sepsis) with manifestation of endotoxemia, dopaminergic support (5.10 mg / kg ∙ min), biochemical criteria of severe sepsis onset (lactate ≥2 mg / L, c-reactive protein ≥ 2 standard abnormalities) and others. The patients were divided into 4 groups: the 1^st and the 2^nd groups were for control studies (SIRS, n = 19); the 3^rd and 4^th groups included patients with severe sepsis (n = 27). The patients from the 2^nd and 4^th were given an infusion load as Ringer's solution in an amount of 7.8 ml / kg at a speed of 18-20 ml / min. Hemodynamic indices were determined by general clinical methods and a portable ultrasound scanner STI PU-2200 (USA).

Results. The paper presents the impact of increasing the volume of extracellular space by means of Ringer's solution, in basic reference, on the system of blood circulation in patients with sepsis-induced hypotension and dopamine-dependent compensation. The most significant results were the registration of a moderate increase in the left ventricle minute work and conservation of the pumping capacity of the heart, stroke volume of the left ventricle and of the ventricular power at the initial level.  However, an increase in adjustable by the pressure frequency by 10 ± 4,6% (Δ, R ≤ 0,05) from the baseline and  by 22% compared to control studies shows the depression of baroreflex regulation of blood circulation. Under these conditions, the constancy of mean arterial pressure was achieved due to an increase in general peripheral vascular resistance as blood stroke volume and systolic blood pressure were reduced; an adequacy of values of minute blood volume and left ventricular minute work were ensured by growth of chronotropic activity; moderate reduction of pumping capacity of the heart was due to the increase of the central venous pressure. In turn, the changes in central venous pressure and increased heart rate formed depression of the frequency adjustable by the pressure.

Conclusions.  1. The program of intensive therapy for severe sepsis onset with dopaminergic support of sepsis-induced hypotension contributes to the creation of compensatory hemodynamic plateau using the values of mean arterial pressure, minute  blood volume and minute volume of the left ventricle. 2. One of the indicators for assessing the state of baroreflex regulation, volume regulation function of the circulatory system in patients with systemic inflammatory response syndrome and severe sepsis in case of an increases in the extracellular space volume is the frequency adjustable by pressure. 3. Among the dysregulatory changes in case of dopamine-dependent compensation in patients with sepsis-induced hypotension in response to the increase in the volume of extracellular space, we observed depression of baroreflex regulation of volume regulation function in the circulatory system, and of contractile activity of the myocardium. Key words: severe sepsis, circulatory system, dopaminergic support, increase in extracellular space volume, systemic inflammatory response syndrome.