Effect of Single-Prong Cannula Design With High Velocity Therapy: Comparable Efficacy at Lower Gas Flow Rates.

Abstract

Objectives: High velocity therapy (HVT), a form of high-flow oxygen therapy, utilizing a small-bore nasal cannula has been widely used in acute care settings. A new dual-prong (newDP) cannula made using more comfortable material and a single-prong (SP) cannula were evaluated to compare comfort and functionality as measured by relief of dyspnea of patients with chronic obstructive pulmonary disease (COPD) receiving HVT therapy.

Design: Randomized crossover evaluation.

Setting: Outpatient and in patient critical care setting.

Patients: Patients with hypercapnic COPD presenting with dyspnea above baseline.

Interventions: HVT therapy was provided using an existing HVT dual-prong nasal cannula (traditional) to determine the most efficacious flow rate. Patients were then randomized to receive either the newDP cannula, or the SP cannula, and retitrated for optimal flow rate. During each session of therapy, Rated Perceived Dyspnea (RPD) scores, vital signs, transcutaneous carbon dioxide partial pressure (PTCco2) levels, and clinician/ patient perceptions were documented.

Measurements and main results: Of 31 enrolled, 26 patients completed the trial. The median flow rate that relieved dyspnea for the traditional, newDP, and SP cannulas were 25 L/min (20-30 L/min), 25 L/min (19.1-30 L/min), and 15 L/min (13-17 L/min), respectively. The change in RPD from baseline for traditional, newDP, and SP were -1 (-1 to 0), -1 (-2 to -1), and -1 (-2 to -1). Change in RPD from baseline for newDP and SP compared with the traditional cannula was significantly different (p = 0.044 and p = 0.01, respectively). Changes in vital signs and PTCco2 were similar between the three cannula types compared with baseline. The SP cannula provided comparable therapeutic efficacy at significantly lower flow rates (traditional vs. SP; p < 0.0001 and newDP vs. SP; p < 0.0001).

Conclusions: The new cannula designs provided comparable relief of dyspnea. The single-prong cannula provided comparable efficacy at significantly lower flow rates (traditional vs. SP; p < 0.0001 and newDP vs. SP; p < 0.0001). The use of a single-prong cannula with HVT warrants further study.