Analysis Of The Outcome Measures Of High Frequency Oscillatory Ventilation (HFOV) In Critically Ill Children With Acute Lung Injury (ALI) And Acute Respiratory Distress Syndrome (ARDS) In Critically Ill Infants And Children.

Abstract

The present study is to evaluate the outcome measures of patients with ALI and ARDS on HFOV in pediatric intensive care unit of Ain Shams University Children's Hospital. The current study included 31 critically ill pediatric patients on mechanical ventilation, with ARDS and ALI, admitted to Ain Shams PICU. Patients were classified into 9 survivors and 22 non- survivors. Patients with past history of chronic pulmonary disorder and patients with cardiac lesion were excluded from the present study. All patients underwent full clinical examination, chest AP view X-ray, laboratory investigation including; complete blood count, CRP, arterial blood gases, scoring of critical illness using pediatric logistic organ dysfunction (PELOD) score and details of ventilatory management on(CMV and HFOV). The main results of the present study were as follows: ALI/ARDS appeared to affect males (51.6%) comparable to females (48.4%) with a ratio of 1.06: 1. In the present study bronchopneumonia has a highest incidence as a cause of direct lung injury (74.2%), aspiration pneumonia (3.2%), while sepsis was the commonest indirect cause of lung injury in ARDS patients (22.6%). In the present study, there was higher percentage (80.65%) of marked lung injury PaO2/FiO2 ≤ 200 (moderate and severe ARDS according to Berlin definition) compared to those with ALI (19.35%) PaO2/FiO2 ≤ 300 or mild ARDS according to Berlin definition. Subsequently the recorded mortality rate was 71 % (9 survivors and 22 non-survivors). The results in the present study revealed significant differences between early and rescue HFOV patients:- Mean Glasgow score (at the end of HFOV) was significantly lower among rescue HFOV patients compared to early HFOV patients. Median total PELOD and Predicted mortality (at the end of HFOV) were significantly higher among rescue HFOV patients compared to early HFOV patients. Mean MAP, PaCO2 and FiO2 (at the end of HFOV setting) were significantly lower among early HFOV patients compared to rescue HFOV patients. Mean oxygenation index (after 6 hours on HFOV) was significantly lower among early HFOV patients compared to rescue HFOV patients. Mean PaO2/FiO2, pH and PaO2 (at the end of HFOV) were significantly higher among early HFOV patients compared to rescue HFOV patients. Outcome measures among early HFOV patients and rescue HFOV patients: Median length of PICU stay was lower among early HFOV patients compared to rescue HFOV patients though the difference was not significant. There were significantly lower median mechanical ventilator days among early HFOV patients compared to rescue HFOV patients. Early HFOV patients were all survivors, while (84.6%) of rescue HFOV patients died and the difference was significant. The results in the present study revealed significant differences between survivors and non survivors:- Sepsis was the commonest indirect cause of ALI/ ARDS among non survivors, while bronchopneumonia was the primary Cause of ALI/ ARDS among survivors though the difference was not significant. Mean Glasgow score was significantly lower among non-survivors compared to survivors. Median total PELOD and Predicted mortality (at the end of HFOV) were significantly higher among non-survivors compared to survivors. Mean PEEP was significantly lower among survivors compared to non survivors at initial ventilation. Mean tidal volume was significantly lower among survivors compared to non survivors initial and before HFOV. Thirteen patients of non survivors underwent lung recruitment before HFOV, while lung recruitment wasn't done for survivors and the difference was significant. Mean MAP, PaCO2 and FiO2 (at end of HFOV) were significantly lower among survivors compared to non survivors. Mean oxygenation index (after 6 hours on HFOV) was significantly lower among survivors compared to non survivors. Mean PaO2/FiO2, pH and PaO2 were significantly higher among survivors compared to non survivors at the end of HFOV.

Outcome measures in both survivors and non survivors: Median length of PICU stay was significantly lower among survivors compared to non survivors. There were significantly lower median mechanical ventilator days (total ventilator days) among survivors compared to non survivors. Early mortality of studied patients (at day 5 of PICU stay) was (16.13%), while a 30 day mortality of studied patients was 71% (n=22/31) though the difference was not significant. None of survivors required supplemental oxygen or mechanical ventilation at day 30.