Prospective pilot study for evaluation of high‐flow oxygen therapy in dyspnoeic dogs: the HOT‐DOG study

Abstract

Objectives To describe the use, effectiveness and tolerance of high‐flow oxygen therapy in dyspnoeic dogs. Materials and Methods Prospectively, dogs in acute respiratory distress admitted to an intensive care unit between January and May 2018 that failed to respond to nasal oxygen therapy and medical stabilisation after 30 minutes were transitioned to high‐flow oxygen therapy. High‐flow oxygen therapy, delivered an inspired oxygen fraction of 100% using an air/oxygen blender, active humidifier, single warmed tube and specific nasal cannula. Respiratory rate, pulse oximetry (SpO2), heart rate and a tolerance score were assessed every 15 minutes from T0 (under nasal oxygen) to 1 hour (T60), and PaO2 and PaCO2 at T0 and T60. Complications were recorded for each dog. Results Eleven dogs were included. At T60, PaO2, flow rate and SpO2 were significantly greater than at T0 (171 ± 123 versus 73 ± 24 mmHg; P=0.015; 18 ±12 L/minute versus 3.2 ± 2.0 L/minute, P<0.01; 97.7 ±2.3% versus 91.6 ±7.2%, P=0.03, respectively). There was no significant difference in PaCO2, respiratory rate or heart rate between T0 and T60. Tolerance was excellent, and there were no complications. Clinical Significance High‐flow oxygen therapy improves markers of oxygenation in dyspnoeic dogs and is an effective means to deliver oxygen with comfort and minimal complications.

Impact of flow and temperature on non‐dyspnoeic dogs' tolerance undergoing high‐flow oxygen therapy

“…In order to assure the delivery of the predetermined FIO 2 , the flow rate of HFNOT should be set above the minute ventilation (MV) of the dog [MV = respiratory rate (bpm) × tidal volume (mL/kg)] (Helviz & Einav 2018, Pouzot‐Nevoret et al . 2019). For each dog, theoretical MV was calculated with a standard respiratory rate (RR) of 20 bpm and a tidal volume of 20 mL/kg considering these dogs were healthy (Testa et al .…”

“…The TS to HFNOT was blindly assessed by the same experienced observer CH, using a simple descriptive scale (Table 1; Pouzot‐Nevoret et al . 2019). This scale ranges from 1 (least tolerant) to 4 (most tolerant).…”

“…HFNOT uses an air‐oxygen blender connected to a flow meter, an active humidifier and heater, a warmed breathing circuit and a specific bilateral nasal cannula (Pouzot‐Nevoret et al . 2019). Respiratory support delivered with HFNOT machines is achieved by administration of humidified air/oxygen blends, using high‐flow rates up to 60 L/min, adjustable fraction of inspired oxygen (FIO 2 ) from 21 to 100%, and precise temperature, between 31 and 37°C (Mauri et al .…”

“…2019, 2020, Pouzot‐Nevoret et al . 2019). Described flow rates in dogs range from 0.2 to 2.5 L/kg/min (Jagodich et al .…”

“…2019, 2020; Pouzot‐Nevoret et al . 2019) or predefined flow rates of 20 to 30 L/min (Daly et al . 2017) all derived from human medicine (Kernick & Magarey 2010, Mayfield et al .…”