Pilot Study of Physiological Effect of High-Flow Nasal Cannula on Respiratory Pattern and Work of Breathing

Summary

Patients affected with severe parenchymal pulmonary diseases, such as Chronic Obstructive Pulmonary Disease (COPD ), may experience dyspnea at rest due to increased work of breathing and reduced oxygenation. The delivery of high-flow humidified nasal oxygen (HFNC) has been shown to have a positive-end-expiratory pressure (PEEP) effect and is able to flush out CO2 from the upper airways, reducing dead space ventilation. Furthermore it has been proven to reduce the respiratory rate shortly after its initiation. These multiple actions offer the potential of changing the respiratory pattern and reducing work of breathing, improving the efficiency of breathing.

In this short-term, physiological, open, randomized, cross-over pilot study the investigator swill describe the effects of varying settings of high-flow nasal oxygen on respiratory rate, tidal volume, and diaphragmatic work of breathing in patients with severe COPD. The investigators will also describe changes in gas exchange and effects on the subjects' comfort and dyspnea and the breathing responses to varying setting of CPAP in the subject population.

Conditions

• COPD

Interventions

OTHER

Esophageal and gastric balloons

Esophageal and gastric pressures will be measured with an esophageal ballon positioned at the lower third of the esophagus, filled with 0.5 mL of air and a gastric balloon filled with 1 mL of air. The proper position of balloons will be verified using the occlusion test as previously described. Transdiaphragmatic pressure (Pdi) is calculated as the difference between gastric (Pga) and esophageal (Pes) pressure. The pressure time integrals of the diaphragm and the other inspiratory muscles are calculated per breath (PTPdi/b and PTPes/b, respectively) and per minute (PTPdi/min and PTPes/min). Measurements will be collected at baseline, at each randomized HFNC and CPAP settings during the last 4 minutes of each 10 minutes session.

OTHER

Respiratory Inductance Plethysmography (RIP) system

Inspiratory tidal volume (VTi), respiratory rate (RR), breath duration (Ttot), inspiratory time (Ti) and fractional inspiratory time (Ti/Ttot) will be determined using a Respiratory Inductive Plethysmography (RIP) system. This will measure the thoracic and abdominal excursion of the subjects via two inductive wires which are sewn into the elastic bands that encircle the thorax and abdomen. The acquired signals represent changes in cross-sectional area and, following calibration to determine the relative contribution of each signal, and volume calibration using spirometry, their weighted sum will reflect VTi. The RIP companion software will be used to derive RR, Ttot, Ti and Ti/Ttot on a breath by breath basis.

OTHER

Sentec transcutaneous monitoring system

The oxygenation, the level of carbon dioxide, and the heart rate will be recorded using the Sentec transcutaneous monitoring system: a probe will be placed at the earlobe or on the forehead, and it will measure in a noninvasive way these parameters.

DEVICE

High-flow humidified nasal oxygen delivery system

DEVICE

CPAP (Positive Control)

Sponsors & Collaborators

• Fisher and Paykel Healthcare

  collaborator INDUSTRY

• Tufts Medical Center

  lead OTHER

Principal Investigators

• Nicholas S Hill, MD · Tufts Medical Center

Study Design

Allocation

RANDOMIZED

Purpose

OTHER

Masking

NONE

Model

CROSSOVER

Eligibility

Min Age

18 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2015-07-31

Primary Completion

2017-12-31

Completion

2018-04-01

Countries

• United States

Study Locations