Bronquiolitis aguda: evaluación del tratamiento basada en la evidencia

[Heliox-driven bronchodilator nebulization in the treatment of infants with bronchiolitis]

INTRODUCTION

Heliox is a helium-oxygen mixture which improves laminar flow and decreases airway resistance and the work of breathing. The aim of this study was to assess the effects of salbutamol or epinephrine nebulization driven by heliox in infants with moderate-to-severe bronchiolitis.

MATERIALS AND METHODS

This prospective, observational, interventional, controlled and randomized study included ninety-six children who came to our pediatric emergency department with first episode of moderate-to-severe bronchiolitis. The patients were randomized to receive salbutamol or epinephrine nebulized with either oxygen (control group) or heliox (70% helium and 30% oxygen) as the driving gas. Heart rate, respiratory rate, pulse oximetry oxygen saturation and clinical score were measured before and after the treatment period. We also reported hospitalization rates and the number of patients who returned to the emergency department in the following seventy two hours.

RESULTS

There were no significant differences between both groups. The only statistically significant difference was that, in the heliox group, patients with severe bronchiolitis needed a lower number of nebulizations than infants in the control group.

CONCLUSIONS

According to our study, heliox-driven salbutamol or epinephrine is not an effective therapy in patients with acute bronchiolitis.

Nasal continuous positive airway pressure with heliox in infants with acute bronchiolitis

This is the first study aiming to assess the effects of heliox in combination with nasal continuous positive airway pressure (Hx-nCPAP) as a rescue treatment in infants with refractory acute bronchiolitis. Fifteen out of 78 infants with acute bronchiolitis consecutively admitted to PICU fulfilled the inclusion criteria: clinical score>or=5 or arterial oxygen saturation (SatO2)<or=92% or PCO2>50 mmHg, despite supportive therapy, nebulized L-epinephrine, and heliox therapy through non-rebreathing reservoir facemask. Hx-nCPAP was added as a rescue treatment. Baseline mean (standard deviation) values were: clinical score of 7.4 (1.2) points; PCO2 of 63.8 (12) mmHg; respiratory rate (RR) of 66.4 (9.9); and SatO2 of 88.6 (4.7)%. Clinical score, PCO2, RR and SatO2 improved during the study time (P<0.05). After 1 h the mean clinical score decreased by 1.5 points, with a total average decrease of 3.5 points at the end of the study period. The mean PCO2 diminished by 9 and 25 mmHg, after 1 and 48 h, respectively. The mean RR decreased 13 rpm after 1 h and 30 rpm after 48 h. The Hx-nCPAP total duration ranged from 2 to 14 days. Only one patient required endotracheal intubation. No adverse effects were detected. All patients recovered fully. In conclusion, Hx-nCPAP improved the clinical score, decreased the tachypnea and enhanced the CO2 elimination of infants with refractory acute bronchiolitis within 1h of administration, in a safe and non-invasive manner. Hx-nCPAP might reduce the need for endotracheal intubation. Further studies are needed.

Ventilación mecánica en la bronquiolitis

Bronchiolitis is a prevalent viral disease in infants. Many of these infants require hospital admission and mechanical ventilation due to respiratory failure or apnea. The clinical and pathophysiological spectrum of this disease can range from two extremes, obstructive and restrictive disease, on which the indication for mechanical ventilation and the modality used should be based. Non-invasive ventilation is especially indicated in both obstructive and hypoxemic restrictive patterns and a pressure-controlled modality is recommended. In obstructive patterns, air trapping must be monitored, while in restrictive patterns the addition of positive end-expiratory pressure (PEEP) is indicated. High-frequency oscillatory ventilation is indicated in restrictive patterns with sever hypoxemia despite conventional ventilatory support or in cases of significant air leak syndromes. In all cases, a permissive hypercapnia strategy is recommended to prevent barotrauma. Sedation and muscle relaxation should be considered to facilitate adaptation to the ventilator and to try to limit the risks of air trapping, air leak, and barotrauma.