Acute Responses to Oxygen Delivery via High Flow Nasal Cannula in Patients with Severe Chronic Obstructive Pulmonary Disease—HFNC and Severe COPD

Abstract

Differences in oxygen delivery methods to treat hypoxemia have the potential to worsen CO2 retention in chronic obstructive lung disease (COPD). Oxygen administration using high flow nasal cannula (HFNC) has multiple physiological benefits in treating respiratory failure including reductions in PaCO2 in a flow-dependent manner. We hypothesized that patients with COPD would develop worsening hypercapnia if oxygen fraction was increased without increasing flow rate. We evaluated the acute response to HFNC in subjects with severe COPD when flow remained constant and inspired oxygen was increased. In total, 11 subjects with severe COPD (FEV1 < 50%) on supplemental oxygen with baseline normocapnia (PaCO2 < 45 mm Hg; n = 5) and hypercapnia (PaCO2 ≥ 45 mm Hg; n = 6) were studied. Arterial blood gas responses were studied at three timepoints: Baseline, HFNC at a flow rate of 30 L/min at resting oxygen supplementation for 1 h, and FiO2 30% above baseline with the same flow rate for the next hour. The primary endpoint was the change in PaCO2 from baseline. No significant changes in PaCO2 were noted in response to HFNC applied at baseline FiO2 in the normocapnic and hypercapnic group. At HFNC with FiO2 30% above baseline, the normocapnic group did not show a change in PaCO2 (baseline: 38.9 ± 1.8 mm Hg; HFNC at higher FiO2: 38.8 ± 3.1 mm Hg; p = 0.93), but the hypercapnic group demonstrated significant increase in PaCO2 (baseline: 58.2 ± 9.3 mm Hg; HFNC at higher FiO2: 63.3 ± 10.9 mm Hg; p = 0.025). We observed worsening hypercapnia in severe COPD patients and baseline hypercapnia who received increased oxygen fraction when flow remained constant. These data show the need for careful titration of oxygen therapy in COPD patients, particularly those with baseline hypercapnia when flow rate is unchanged.

Transnasal High-Flow Oxygen Therapy versus Noninvasive Positive Pressure Ventilation in the Treatment of COPD with Type II Respiratory Failure: A Meta-Analysis

“…However, NIV has disadvantages, such as reduced comfort and poor interaction and synchronization between patients and ventilators, which are often difficult to identify and manage [ 26 ]. In recent years, HFNC has been increasingly applied in stabilizing and aggravating COPD patients [ 27 ].…”

High-Flow Nasal Cannula Oxygen Therapy in the Management of Respiratory Failure: A Review

“…HFNC appears to be superior in terms of patient comfort and reduces complications of therapy. However, caution should be exercised in hypercapnic AECOPD as there is some evidence of worsening hypercapnia with higher FiO 2 for unchanged flow rates [ 34 ]. Further RCTs with large sample sizes are required to explore the direct comparison of HFNC versus NIV, especially with the advancement of both the nasal cannulae and high-flow oxygen delivery systems.…”

2021 Guideline for the Management of COPD Exacerbations

“…In a recent study, it has been reported that in HFNOT, the flow rate remains constant while the oxygen fraction is increased, which causes a deterioration in PaCO 2 . [ 13 ] A clinical question comparing the use of HFNOT with standard oxygen therapy and NIMV in exacerbations was evaluated, and recommendations were made in Section 6.9.1.…”