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High-flow humidified nasal cannula is often used to provide noninvasive respiratory support in children. The effect of high-flow humidified nasal cannula on effort of breathing in children has not been objectively studied, and the mechanism by which respiratory support is provided remains unclear. This study uses an objective measure of effort of breathing (Pressure. Rate Product) to evaluate high-flow humidified nasal cannula in critically ill children.Prospective cohort study.Quaternary care free-standing academic children's hospital.ICU patients younger than 18 years receiving high-flow humidified nasal cannula or whom the medical team planned to extubate to high-flow humidified nasal cannula within 72 hours of enrollment.An esophageal pressure monitoring catheter was placed to measure pleural pressures via a Bicore CP-100 pulmonary mechanics monitor. Change in pleural pressure (ΔPes) and respiratory rate were measured on high-flow humidified nasal cannula at 2, 5, and 8 L/min. ΔPes and respiratory rate were multiplied to generate the Pressure.Rate Product, a well-established objective measure of effort of breathing. Baseline Pes, defined as pleural pressure at end exhalation during tidal breathing, reflected the positive pressure generated on each level of respiratory support.Twenty-five patients had measurements on high-flow humidified nasal cannula. Median age was 6.5 months (interquartile range, 1.3-15.5 mo). Median Pressure,Rate Product was lower on high-flow humidified nasal cannula 8 L/min (median, 329 cm H2O·min; interquartile range, 195-402) compared with high-flow humidified nasal cannula 5 L/min (median, 341; interquartile range, 232-475; p = 0.007) or high-flow humidified nasal cannula 2 L/min (median, 421; interquartile range, 233-621; p0.0001) and was lower on high-flow humidified nasal cannula 5 L/min compared with high-flow humidified nasal cannula 2 L/min (p = 0.01). Baseline Pes was higher on high-flow humidified nasal cannula 8 L/min than on high-flow humidified nasal cannula 2 L/min (p = 0.03).Increasing flow rates of high-flow humidified nasal cannula decreased effort of breathing in children, with the most significant impact seen from high-flow humidified nasal cannula 2 to 8 L/min. There are likely multiple mechanisms for this clinical effect, including generation of positive pressure and washout of airway dead space.

This study describes the 15-yr experience of a large urban tertiary care children's hospital in treating critically ill patients with pediatric rheumatic diseases.Retrospective case series.Children's Hospital Los Angeles, a large urban tertiary care children's hospital.All patients with pediatric rheumatic diseases admitted to the Children's Hospital Los Angeles pediatric intensive care unit from January 1995 to July 2009.None.An internal database and medical records were reviewed for demographics, diagnoses, treatments, organ dysfunction, interventions, infections, and outcomes. Standardized mortality ratio was calculated based on Pediatric Risk of Mortality III estimated mortality. Factors associated with mortality were identified by univariate analyses.Ninety patients with 122 total admissions were identified. The majority of patients were Hispanic (63%), female (73%), and had systemic lupus erythematosus (62%). Pediatric rheumatic disease-related complications (50%) were the most common reason for admission; 32% of admissions involved multiorgan dysfunction. Eighteen admissions (15%) resulted in mortality. Deaths were most commonly attributed to combined infection and active rheumatic disease (50%), infection only (22%), rheumatic disease only (11%), or other causes (17%). In 30 (25%) admissions, a new rheumatologic diagnosis was established. Standardized mortality ratio was 0.72 (95% confidence interval 0.38-1.25) for pediatric rheumatic disease patients compared to 0.87 (95% confidence interval 0.79-0.96) for all pediatric intensive care unit patients. Factors associated with mortality included use of mechanical ventilation, vasopressors, and renal replacement (continuous venovenous hemodialysis) (all p.05).Pediatric rheumatic disease-related complications were the principal cause of pediatric intensive care unit admission. Deaths occurred most often from severe infections in patients with active rheumatic disease. Pediatric rheumatology patients admitted to the pediatric intensive care unit had outcomes similar to the global pediatric intensive care unit population when adjusted for severity of illness.