The effects of flow settings during high-flow nasal cannula oxygen therapy for neonates and young children.

BACKGROUND: During neonatal and paediatric high-flow nasal cannula therapy, optimising the flow setting is crucial for favourable physiological and clinical outcomes. However, considerable variability exists in clinical practice regarding initial flows and subsequent adjustments for these patients. Our review aimed to summarise the impact of various flows during high-flow nasal cannula treatment in neonates and children. METHODS: Two investigators independently searched PubMed, Embase, Web of Science, Scopus and Cochrane for in vitro and in vivo studies published in English before 30 April 2023. Studies enrolling adults (≥18 years) or those using a single flow setting were excluded. Data extraction and risk of bias assessments were performed independently by two investigators. The study protocol was prospectively registered with PROSPERO (CRD42022345419). RESULTS: 38 406 studies were identified, with 44 included. In vitro studies explored flow settings' effects on airway pressures, humidity and carbon dioxide clearance; all were flow-dependent. Observational clinical studies consistently reported that higher flows led to increased pharyngeal pressure and potentially increased intrathoracic airway pressure (especially among neonates), improved oxygenation, and reduced respiratory rate and work of breathing up to a certain threshold. Three randomised controlled trials found no significant differences in treatment failure among different flow settings. Flow impacts exhibited significant heterogeneity among different patients. CONCLUSION: Individualising flow settings in neonates and young children requires consideration of the patient's peak inspiratory flow, respiratory rate, heart rate, tolerance, work of breathing and lung aeration for optimal care.

Impact of Breathing Pattern and Nebulization on Expelled Viral Content During Mechanical Ventilation Using an Ex Vivo Porcine Lung System.

BACKGROUND: Little is known about the fate of expelled viral particulates during the aerosolization of inhaled medications during mechanical ventilation. We hypothesized that breathing patterns that generate a greater degree of shear stress and turbulent air flow will produce a greater concentration of exhaled viral RNA with the presence of a nebulizer during mechanical ventilation. METHODS: Eight ex vivo pig lungs were utilized as the physiological model. Each lung was dedicated to a specific breathing pattern that consisted of tidal breathing, respiratory distress, cough, and sneeze. Breath simulations were carried out through a commercial mechanical ventilator. Ninety mL of a bacteriophage stock at a concentration of 108 PFU/mL were introduced into the lungs during a 10-min sample collection session. The number of viral particles collected in exhalate was measured using quantitative polymerase chain reaction. The impact of breathing pattern on measured viruses was analyzed through two-way analysis of variance. RESULTS: The interaction effect between nebulization and breath pattern on exhaled viral quantity was not statistically significant P = .80, partial η2 = 0.167. The analysis of the main effects indicated that the effects of the breathing pattern and nebulization phase were not statistically significant P = .26, partial η2 = 0.519; P = .98, partial η2 = 0, respectively. There were no statistically significant differences among the breathing patterns related to measurable viral RNA. Coughing produced the most measurable increase in measured viral quantity during the nebulization phase and non-nebulization phase with a mean exhaled viral quantity (3.5 × 105 ng/µL [95% CI 1.6 × 105-5.5 × 105] and 2.7 × 105 ng/µL [95% CI 7.1 × 103-5.5 × 105], respectively). Tidal breathing with the presence of a nebulizer and respiratory distress without a nebulizer produced the lowest measured viral quantities (M = 1.1 × 105 ng/µL [95% CI -1.7 × 105 to 3.9 × 105]; M = 1.2 × 105 ng/µL [95% CI -1.6 × 105 to 4.0 × 105]). CONCLUSIONS: In this ex vivo porcine model, the introduction of a nebulizer did not increase the mean viral RNA captured throughout all of the breathing patterns.

Danger in the vapor? ECMO for adolescents with status asthmaticus after vaping.

Introduction: Electronic nicotine delivery systems (ENDS) use is on the rise in the adolescent and young adult populations, especially in the wake of sweet flavored ENDS solutions and youth-targeted marketing. While the extent of effect of ENDS use and aerosolized flavorings on airway epithelium is not known, there remains significant concern that use of ENDS adversely affects airway epithelial function, particularly in populations with asthma.Case Study: In this case series, we review two cases of adolescents with history of recent and past ENDS use and asthma who required veno-venous extracorporeal membrane oxygenation (VV-ECMO) for status asthmaticus in the year 2018.Results: Both patients experienced hypercarbic respiratory failure requiring VV-ECMO secondary to their status asthmaticus, with slow recovery on extensive bronchodilator and steroid regimens. They both recovered back to respiratory baseline and were counseled extensively on cessation of ENDS use.Conclusion: While direct causation by exposure to ENDS cannot be determined, exposure likely contributed to symptoms. Based on the severity of these cases and their potential relationship with ENDS use, we advocate for increased physician screening of adolescents for ENDS use, patient and parent education on the risks of use, and family cessation counseling.