Diaphragmatic dysfunction in mechanically ventilated children: a prospective observational cohort study

Abstract

Background. Mechanical ventilation (MV) can cause diaphragmatic injury, which is called ventilator-induced diaphragmatic dysfunction and is associated with adverse treatment outcomes, prolonged weaning from respiratory therapy, and prolonged stay in the intensive care unit. The purpose of the study was to determine the prevalence of diaphragmatic dysfunction in children depending on the strategy of mechanical ventilation. The study hypothesis was that the occurrence of diaphragmatic dysfunction does not depend on the strategy of mechanical ventilation. Materials and methods. We conducted a prospective cohort single-center study at the Department of Anesthesiology and Intensive Care at Lviv Regional Children’s Clinical Hospital “OHMATDYT”. We included patients with acute respiratory failure who were mechanically ventilated for more than 3 days. Exclusion criteria for the study were: the refusal of the patient’s legal representatives to participate in the study at any of its stages, the patient’s agonizing state upon admission, and the onset of MV less than 48 h after prior weaning. The study included 89 indivi­duals aged 1 month — 18 years. All patients were randomly divided into 2 groups (using random.org). Group I included people who received lung-protective ventilation strategy, group II — patients who received diaphragm-protective in addition to lung-protective ventilation strategy. Eighty-two patients were included in the data analysis. We studied indicators of diaphragmatic function (amplitude of diaphragm movement, thicke­ning fraction, and it was considered that decrease of this indicator for less than 15 % was a marker of diaphragmatic weakness; its increase up to more than 35 % was a marker of high respiratory function and a potentially damaging factor for diaphragm; and inspiration time), parameters of acid-base balance and mechanical ventilation. To assess age-dependent data, patients were divided into age subgroups: subgroup 1— children aged 1 month — 1 year; subgroup 2 — children aged 1–3 years; subgroup 3 — children aged 3–6 years; subgroup 4 — children 6–13 years; subgroup 5 — children aged 13–18 years. Stages of the study: days 1 (d1), 3 (d3), 5 (d5), 7 (d7), 9 (d9), 14 (d14), 28 (d28). Results. Thus, we identified age-specific features of diaphragmatic dysfunction during MV: in patients of the first age subgroup in group I, there were found weakness for the right hemidiaphragm with compensatory excessive level of work for the left dome at the beginning of weaning and at stage d9, while in group II diaphragmatic overload was registered only at stage d5. In patients of the second age subgroup in group I, changes were the opposite to those described previously: we found excessive work of the right hemidiaphragm with low contractions of left dome at all stages of study in group I, while in group II the only episode of diaphragmatic weakness was in stage d3. In the third age subgroup, the proper diaphragmatic activity in group I of patients was restored later than in II group. In the fourth age subgroup in group I, there was an episode of high work of the diaphragm at stage d5, whereas in group II all data of diaphragmatic function were within the recommended parameters for diaphragm-protective strategy of MV at all stages of our study. In the fifth age subgroup in group I, an excessive work of both right and left domes of the diaphragm was significantly more often registered during weaning than in group II; however, in group II episodes of both types of changes — diaphragmatic weakness and excessive work — were detected. It was found that adding diaphragm-protective strategy of weaning from mechanical ventilation in comprehensive intensive care allowed us to reduce the duration of mechanical ventilation: in patients of the first age subgroup — by 1.5 times (p = 0.08); in patients of the second subgroup — by 2.4 times (p = 0.18); in the fourth age subgroup — by 1.75 times (p = 0.1); in fifth age subgroup — by 4.25 times (p = 0.009). In patients of the third age subgroup, duration of mechanical ventilation increased by 1.1 times (p = 0.68). The frequency of complications (reintubations) was reduced in the first age subgroup by 4.3 times (p = 0.02); in the second age subgroup — by 3.4 times (p = 0.04). Conclusions. The prevalence and variety of manifestations of diaphragmatic dysfunction depend on the strategy of mechanical ventilation. Comprehensive approach during weaning from respiratory therapy, which includes diaphragm-protective strategy of ventilation, reduces the incidence of diaphragmatic dysfunction and the duration of weaning from MV.