HFNC Flow Titration and Effort of Breathing in the PICU

Not Applicable

Completed

Conditions: High Flow Nasal Cannula

Interventions: Device: Fisher & Paykel high flow nasal cannula
Device: Vapotherm high flow nasal cannula

Registration Number: NCT02793674

Lead Sponsor: Children's Hospital Los Angeles

Brief Summary: High-flow nasal cannula (HFNC) is a method of non-invasive respiratory support used to decrease the effort of breathing (EOB) in patients with a wide variety of respiratory diseases in the pediatric intensive care unit. While its use has shown association with decreased rates of mechanical ventilation, there is a paucity of data examining its direct effect upon objective measurements of EOB. This study will aim to evaluate objective measurements of EOB in response to different levels of HFNC support, characterize the natural course of respiratory diseases treated with HFNC, evaluate changes in EOB secondary to the administration of supplemental medical therapies used in conjunction with HFNC, and compare different physiologic metrics for quantifying EOB in patients on HFNC.

Detailed Description: Not available

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 21

Inclusion Criteria

All participants less than or equal to three years old admitted to the PICU placed on high flow nasal cannula will be considered eligible for the study.

Exclusion Criteria

Participants will be excluded if they have a corrected gestational age less than 37 weeks or contraindications to nasoesophageal catheter placement (nasopharyngeal or esophageal abnormalities) or RIP bands (abdominal wall defects such as omphalocele). Patients greater than three years of age will be excluded.

Study & Design

Study Type: INTERVENTIONAL

Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
Fisher & Paykel high flow nasal cannula	Fisher & Paykel high flow nasal cannula	All participants in the study were on one or two high flow nasal cannula (HFNC) delivery systems. All were measured on the Fisher \& Paykel HFNC delivery system. The flow rate of the HFNC was adjusted to determine if there exists a change in their effort of breathing.
Vapotherm high flow nasal cannula	Vapotherm high flow nasal cannula	All participants in the study were on one or two high flow nasal cannula (HFNC) delivery systems. A subgroup was measured on the Vapotherm HFNC delivery system. The flow rate of the HFNC was adjusted to determine if there exists a change in their effort of breathing.

Primary Outcome Measures

Name	Time	Method
Percent Change in Pressure-rate Product (PRP) as a Function of Increasing HFNC Flow Rate on Both Types of HFNC Delivery System (FP and VT)	median percent change in PRP over 5 minute measurement period	PRP is a validated objective metric of effort of breathing which is derived from the product of the peak-to-trough change in esophageal pressure (in cmH20) and the respiratory rate (breaths per minute). The percent change in PRP is derived from the quotient of the absolute PRP at increased HFNC flow rates (1.0, 1.5, and 2.0 L/kg/min) divided by the absolute PRP at a baseline HFNC flow rate (0.5 L/kg/min). Percent change in PRP was used because a) there was a large degree of heterogeneity in baseline absolute PRP values in our study population based upon patient size, disease severity, and time point of illness, and b) we allowed for repeated measures on the same patient which would bias absolute PRP values in favor of those who were measured more frequently. It was not pre-specified to compare the two different HFNC delivery systems.

Secondary Outcome Measures

Name	Time	Method
Percent Change in Pressure-rate Product (PRP) From Baseline as a Function of Increasing HFNC Flow Rate, Comparing Different HFNC Delivery Systems	median PRP over a 5 minute period	For this outcome, a subgroup of patients (N=12) were examined who had PRP measurements obtained on two different HFNC delivery systems (Fisher \& Paykel (FP) and Vapotherm (VT)) in back-to-back flow titration periods. With one exception, patients were first studied on the FP and then transitioned to the VT HFNC delivery system.
Maximum Percent Change in Pressure-rate Product (PRP) From Baseline as a Function of Increasing HFNC Flow Rate, Comparing Weight-Stratified Subgroups on Both Types of HFNC Delivery System (FP and VT)	median of the maximum percent change in PRP over a 5 minute period	Exploratory analysis of patients by further stratified weight groupings (\<5 kg, 5-8 kg, and \>8 kg) was performed to determine the greatest observed benefit of HFNC flow titration in patients of different sizes. For this outcome, the maximum percent change in PRP was obtained for all titrations on both types of HFNC delivery system (FP and VT). It was not pre-specified to compare the two different HFNC delivery systems.
Pressure-rate Product (PRP) as a Function of Increasing HFNC Flow Rate on Both Types of HFNC Delivery System (FP and VT)	median PRP over a 5 minute period	PRP is a validated objective metric of effort of breathing which is derived from the product of the peak-to-trough change in esophageal pressure (in cmH20) and the respiratory rate (breaths per minute). These values were obtained from 5 minute flow titration periods. For this outcome, the PRP was obtained for all titrations on both types of HFNC delivery system (FP and VT). It was not pre-specified to compare the two different HFNC delivery systems.
Phase Angle as a Function of Increasing HFNC Flow Rate on Both Types of HFNC Delivery System (FP and VT)	median phase angle over a 5 minute period	Phase angle is a measure of asynchrony between thoracic and abdominal breathing compartments that has correlated with increased effort of breathing. It is derived by measuring the relative expansion of these two breathing compartments and describing the synchrony between them as an angle (theta). For this outcome, the phase angle was obtained for all titrations on both types of HFNC delivery system (FP and VT). It was not pre-specified to compare the two different HFNC delivery systems.
Percent Change in Pressure-rate Product (PRP) From Baseline as a Function of Increasing HFNC Flow Rate, Comparing Weight-Stratified Subgroups on Both Types of HFNC Delivery System (FP and VT)	medain percent change in PRP over a 5 minute period	To assess the relationship between patient size and dose-response of HFNC flow rate, we compared subgroups stratified by weight (patients \<8 kg and \>8 kg). For this outcome, the median percent change in PRP was obtained for all titrations on both types of HFNC delivery system (FP and VT). It was not pre-specified to compare the two different HFNC delivery systems.