HEMODYNAMIC CHANGES IN CHILDREN WITH ACUTE RESPIRATORY FAILURE DURING WEANING FROM MECHANICAL VENTILATION

Abstract

Background. Acute respiratory failure is accompanied by increasing load on cardiovascular system. The aim of the study was to investigate functional parameters of cardiovascular system and oxygen delivery in children with acute respiratory failure at different strategies of mechanical ventilation.Materials and methods. We conduct prospective, randomized, non-interventional, single-center controlled trial among patients 1 month – 18 years old. All patients were divided into a control group, which included 75 patients who underwent short-term ventilation during elective surgery and who were weaned immediately after surgery and restoration of physiological functions after anesthesia, and patients of the study group with acute respiratory failure (n = 162), who required invasive mechanical ventilation via endotracheal tube. Patients in the study group were randomized into study group I (83 patients) and received traditional ICU monitoring and treatment and study group II (79 patients), in which we used in addition to traditional monitoring and treatment, proposed by us methods of monitoring and treatment strategy. To assess age-dependent data, patients were divided into age subgroups: 1 subgroup – children 1 month – 1 year; 2nd subgroup – children 1 – 3 years; 3 subgroup – children 3 – 6 years; 4 subgroup – children 6 – 13 years; 5 subgroup – children 13 – 18 years. Stages of the study: 1st day (d1), 3rd day (d3), 5th day (d5), 7th day (d7), 9th day (d9), 14th day (d14), 28th day (d28). The evaluation criteria were heart rate, non-invasive blood pressure (systolic, diastolic and mean), stroke volume, stroke volume index, cardiac output, cardiac index, oxygen delivery.Results. The features of hemodynamics in patients of II study group at weaning from mechanical ventilation, depending on age, were: in the 2nd and 3rd age subgroups in hypoxemic and hypercapnic-hypoxemic forms of respiratory failure – decrease in heart rate at stage d3 by 33% and 40 %, compared with I group patients (p = 0.05 and p = 0.04); reduction of cardiac index by 25% (p = 0.001) in 2nd age subgroup at stage d3 and by 31% (p = 0.02) in the 3rd age subgroup at stage d5. In the 1st and 4th age subgroups of the II study group in hypoxemic and hypercapnic-hypoxemic respiratory failure were stroke volume index decreasing from stage d3, up to 21% (p = 0.04) and up to 37% (p = 0.05 ) for the 1st and 4th subgroups, respectively, together with significant decrease in cardiac output at stage d5, in comparison with I study group. For patients of 5th age subgroup with hypoxemic and hypercapnic-hypoxemic respiratory failure typically were significant decreasing of systolic and mean blood pressure at stage d1 by 17% (p = 0.04) and 24%, respectively (p = 0.001), in comparison with I study group; growth of cardiac output and cardiac index at stage d3 by 13% and 14% (p = 0.05 and p = 0.04). Oxygen delivery rates in patients of the 1st and 3rd age subgroups were significantly decreased from stage d5 by 22% (p = 0.05) and by 31% (p = 0.02), in 2nd and 4th age subgroups – from stage d3 by 25% (p = 0.05) and 29% (p = 0.01), no significant differences were found in patients of the 5th age group.Conclusion. Based on the analysis of hemodynamic parameters, it was found that for all age subgroups of patients with acute respiratory failure, regardless of its form, weaning from mechanical ventilation was characterized by hyperdynamic type of hemodynamic with increasing cardiac index level (5.8 ± 1.1 l/min/m2 vs 2.9 ± 0.4 l/min/m2 (p = 0.001) in control group) and significantly higher (p <0.05) oxygen delivery rates. Hemodynamic parameters were normalized significantly faster in patients of II study group in comparison with I study group with start from stage d3 for the 1st, 2nd, 3rd and 4th age subgroups and from stage d1 for the 5th age subgroup (p <0,05) in II study group.