Impact of Heated Humidified High Flow Air via Nasal Cannula on Respiratory Effort in Patients with Chronic Obstructive Pulmonary Disease

Charles W Atwood Jr; Sharon Camhi; Kathryn C Little; Colleen Paul; Hobart Schweikert; Nicholas J Macmillan; Thomas L Miller

doi:10.15326/jcopdf.4.4.2016.0169

Impact of Heated Humidified High Flow Air via Nasal Cannula on Respiratory Effort in Patients with Chronic Obstructive Pulmonary Disease

Chronic Obstr Pulm Dis. 2017 Aug 15;4(4):279-286. doi: 10.15326/jcopdf.4.4.2016.0169.

Authors

Charles W Atwood Jr^{1

2}, Sharon Camhi^{1

2}, Kathryn C Little³, Colleen Paul¹, Hobart Schweikert¹, Nicholas J Macmillan⁴, Thomas L Miller^{5

6}

Affiliations

¹ Pulmonary Section, Veterans Administration Pittsburgh Healthcare System, Pittsburgh, Pennsylvania.
² Division of Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania.
³ Children's Hospital of Pittsburgh of University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania.
⁴ The MED Group, Inc., Lubbock, Texas.
⁵ Vapotherm, Inc., Exeter, New Hampshire.
⁶ Department of Pediatrics, Sydney Kimmel Medical College, Philadelphia, Pennsylvania.

Abstract

Background: High flow nasal cannula therapy (HFNC) has been widely adopted for respiratory distress, and evidence suggests that purging dead space of the upper airway improves gas fractions in the lung. This study tests the hypothesis that HFNC with room air could be as effective as low flow oxygen in chronic obstructive pulmonary disease (COPD). Methods: Thirty-two COPD patients prescribed 1 - 2 L/min of oxygen were studied. The conditions tested consisted of a control (CTRL; no therapy), then in random order HFNC and prescribed low flow oxygen (LFO). HFNC was the highest flow tolerated up to 35 L/min without supplemental oxygen. Arterial blood gases (ABGs), respiratory rate (RR), heart rate (HR) and tidal volume (V_T) were measured at the end of each condition. Results: Arterial oxygen (PaO₂) was greater (p < 0.001) for LFO than both HFNC and CTRL (CTRL=57.4±6.1mmHg, HFNC=58.6±8.3mmHg, LFO=72.6±10.2mmHg). HFNC reduced RR by 11% (p<0.05) from CTRL and LFO (CTRL=20.2±3.8br/min, HFNC=17.9±3.3br/min, LFO=20.2±3.7br/min) with no differences in V_T. There were no differences between arterial carbon dioxide (PaCO₂) (CTRL=45.5±4.9mmHg, HFNC=45.0±5.3mmHg, LFO=46.0±3.9mmHg). Conclusions: HFNC resulted in a clinically relevant reduction in ventilatory effort with no change in ABG indicating a gas equilibrium effect of purging anatomical dead space. Clinical Trial Registration: ClinicalTrials.gov ID: NCT00990210.

Keywords: dead space; high flow nasal cannula; high velocity nasal insufflation; oxygenation; ventilation; ventilatory efficiency; work of breathing.

Associated data

ClinicalTrials.gov/NCT00990210

Grants and funding

This study was sponsored by Vapotherm, Inc., Exeter, New Hampshire and conducted at the Veterans Administration Pittsburgh Healthcare System, Pittsburgh, Pennsylvania.