Nasal high flow in management of children with status asthmaticus: a retrospective observational study

Abstract

BackgroundAsthma is the most common obstructive airway disease in children and adults. Nasal high flow (NHF) is a recent device that is now used as a primary support for respiratory distress. Several studies have reported use of NHF as a respiratory support in status asthmaticus; however, there are no data to recommend such practice. We therefore conducted this preliminary study to evaluate NHF therapy for children with status asthmaticus admitted to our PICU in order to prepare a multicentre randomized controlled study.ResultsBetween November 2009 and January 2014, 73 patients with status asthmaticus were admitted to the PICU, of whom 39 (53%) were treated with NHF and among these 10 (26%) presented severe acidosis at admission (pH < 7.30). Thirty-four less severe children (41%) were treated with standard oxygen. For one child (2.6%) NHF failed and was then switched to non-invasive ventilation. NHF was discontinued in another patient because of the occurrence of pneumothorax after 31 h with NHF; the patient was then switched to standard oxygen therapy. Mean ± SD heart rate (165 ± 21 vs. 141 ± 25/min, p < 0.01) and respiratory rate (40 ± 13 vs. 31 ± 8/min, p < 0.01) decreased significantly, and blood gas improved in the first 24 h. In the subgroup of patients with acidosis, median [IQR] pH increased significantly between hour 0 and 2 (7.25 [7.21–7.26] vs. 7.30 [7.27–7.33], p = 0.009) and median [IQR] pCO2 decreased significantly (7.27 kPa [6.84–7.91 vs. 5.85 kPa [5.56–6.11], p = 0.007). No patient was intubated.ConclusionThis retrospective study showed the feasibility and safety of NHF in children with severe asthma. Blood gas and clinical parameters were significantly improved during the first 24 h. NHF failed in only two patients, and none required invasive ventilation.

In vitro comparison of unit dose vs infusion pump administration of albuterol via high‐flow nasal cannula in toddlers

“…Previous in vitro and in vivo studies on aerosol delivery via HFNC all utilized unit dose with a single concentration . With unit dose administration, the inhaled dose was 10% to 15% in similar pediatric models, which was consistent with our findings using unit dose delivery.…”

“…However, asthmatic patients might benefit more from effective bronchodilator delivery than the 20% improvement on work of breathing benefited from a higher flow rate. Baudin et al summarized their success in using an intermittent unit dose of albuterol via HFNC for severely asthmatic patients might be due to the relatively low gas flow rate (1 L/kg/min) utilized in their study . Thus decreasing flow to achieve efficient bronchodilator delivery might be a viable strategy.…”

Decrease the flow setting to improve trans‐nasal pulmonary aerosol delivery via “high‐flow nasal cannula” to infants and toddlers

“…Furthermore, when patients need extended periods of aerosol administration, use of mask or mouthpiece is complicated by decreased patient comfort and tolerance. In‐line placement of a nebulizer with HFNC has been described to solve the difficulty and has attracted attention from clinicians in recent years . The survey among American pediatric respiratory therapists showed that 75% of respondents delivered aerosol therapy during HFNC .…”

“…In-line placement of a nebulizer with HFNC has been described to solve the difficulty and has attracted attention from clinicians in recent years. 8,9,[11][12][13] The survey among American pediatric respiratory therapists showed that 75% of respondents delivered aerosol therapy during HFNC. 14 Pediatric patients were reported to be more comfortable and less anxious after inhaling aerosol bronchodilator via HFNC, 8,9 which has also shown the potential benefits of avoiding intubation in a group of pediatric asthma patients, 26% of whom already had acidosis at PICU admission.…”

“…14 Pediatric patients were reported to be more comfortable and less anxious after inhaling aerosol bronchodilator via HFNC, 8,9 which has also shown the potential benefits of avoiding intubation in a group of pediatric asthma patients, 26% of whom already had acidosis at PICU admission. 11 Aerosol delivery via HFNC for pediatric patients has been characterized by means of in vitro 10,[15][16][17][18] and radiolabeled in vivo studies. 10 Reported in vitro inhaled dose in pediatric patients is ≤5%, 10,15,17,18 with the exception of one study reporting that inhaled dose increased from 5.4% to 11% as nasal cannula gas flow was reduced from 6 to 3 L/min.…”