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Objective: High-flow nasal cannula use in the PICU continues to increase; however, a protocol for weaning patients has yet to be published. This study aimed to create an efficient and safe protocol for weaning high-flow nasal cannula., Design: A Respiratory Assessment Score was created using two validated scoring systems. A protocol was established for set "holidays" off high-flow nasal cannula, where nasal cannula flow was reduced to age-based low-flow nasal cannula rates if Respiratory Assessment Scores met certain criteria., Setting: The PICU at Children's Healthcare of Atlanta at Egleston, a quaternary level hospital affiliated with Emory University., Patients: Patients treated in the PICU with high-flow nasal cannula from August 2013 to March 2014. Exclusions included apnea, heliox therapy, oxygen saturations less than 92% with a FIO2 greater than 50%, admitted to PICU less than 6 hours, progression to intubation prior to scoring, or those ordered by physician to not receive holidays based on clinical status., Interventions: Patients who qualified for a "holiday" based on Respiratory Assessment Score were trialed off high-flow nasal cannula and rescored afterwards to assess tolerance., Measurements and Main Results: One hundred thirty-three patients were treated with high-flow nasal cannula, with the most common diagnosis being bronchiolitis (43%). Of these 133 patients, 119 (89.5%) successfully weaned to low-flow nasal cannula within four holiday attempts. Eighty-three patients (70%) weaned with only one attempt. Fourteen patients (10.5%) failed to wean. Reasons for failure were reintubation, increasing flow on high-flow nasal cannula, too high of Respiratory Assessment Score to meet weaning criteria, or slow weaning after failed attempts. Holidays did not precipitate clinical deterioration or lead to immediate intubation., Conclusions: Our study suggests that a high-flow nasal cannula "holiday" protocol is a safe and effective way to successfully wean PICU patients off high-flow nasal cannula. Additional investigation including validation of the scoring system used is warranted.

Objective: To determine which flow setting most accurately detects the lower inflection point (Pflex) using an automated constant flow method and varying endotracheal tube (ETT) sizes with and without an airleak in a pediatric lung model., Design: Interventional laboratory study., Setting: Children's hospital research center., Interventions: A pediatric lung model was created with Pflexs of the inspiratory pressure-volume (P-V) curve set at 5 and 10 cm H2O using the ASL 5000 Test Lung (IngMar Medical, Pittsburgh, PA). Three ETT sizes (3.0, 4.0, 5.0 mm) were tested with and without a 25% airleak. P-V curves were obtained using an automated constant flow method at ten different flow rates., Measurements and Main Results: Without an ETT airleak, the lowest flow of 0.5 L/min led to the most accurate determination of Pflex regardless of ETT size or set Pflex (p < 0.001). When a 25% leak was introduced, accuracy of measured Pflex depended on both ETT size (p < 0.001) and flow rate (p < 0.001). Optimum flow rates for Pflex determination were 0.5, 1.0, and 1.5 L/min at Pflex of 5 cm H2O, and 2.0, 3.5, and 4.5 L/min at 10 cm H2O for 3.0, 4.0, and 5.0 mm ETTs, respectively (p < 0.001)., Conclusions: Estimation of Pflex can be achieved using automated P-V curves with ETTs appropriate for pediatric use, with and without an airleak. ETT size and flow rate affect the accuracy of these measurements when an airleak is present, and use of increased flow rates to create the automated P-V curves can reduce error. These data support the idea that a low-flow technique provides the most accurate determination of Pflex in pediatric patients without a leak around their ETT, whereas increased flows are needed to compensate when an ETT airleak is present.

Objective: To identify the effect of perflubron on gas exchange and lung mechanics during high frequency oscillatory ventilation in an animal model., Design: Prospective randomized animal trial., Subjects: Eighteen Yorkshire swine., Interventions: Three groups of six animals each were investigated: control (high frequency oscillatory ventilation alone), low dose perflubron (high frequency oscillatory ventilation plus perfluoro-octyl bromide [PFOB]-Lo, 1.5 mL/kg), and high dose perflubron (high frequency oscillatory ventilation plus PFOB-Hi, 3 mL/kg). Lung injury was induced with repeated saline lavage and amplified for 1 hr using large tidal volumes. Perflubron (Alliance, CA) or a sham dose (room air) was administered with bronchoscopic guidance. The animals were transitioned to high frequency oscillatory ventilation starting at a mean airway pressure of 15 cm H2O. Mean airway pressure was increased (inflation phase) by 5 cm H2O every 15 mins to a maximum mean airway pressure of 40 cm H2O. During the deflation phase, mean airway pressure was reduced by 5 cm H2O every 15 mins to a mean airway pressure of 15 cm H2O., Measurements and Main Results: Oxygenation was improved and pulmonary shunt fraction was reduced for PFOB-Hi compared with the control group only at a mean airway pressure of 15 and 20 cm H2O. At a maximal mean airway pressure of 40 cm H2O, oxygenation was not different between the groups, but pulmonary artery pressures were elevated in both PFOB-groups compared with the control group. During the deflation phase, oxygenation, pulmonary shunt fraction, and pulmonary artery pressures were adversely affected by PFOB-Hi and PFOB-Lo., Conclusions: Although PFOB-Hi compared with the control group improved oxygenation and reduced pulmonary shunt fraction only during the first pressure steps of a formal stepwise recruitment maneuver during high frequency oscillatory ventilation, this effect was not sustained during maximal recruitment. During the deflation phase, both PFOB groups were associated with worse gas exchange compared with the control group. PFOB also produced significant pulmonary hypertension in comparison with the control group.