The utility of the respiratory rate-oxygenation index as a predictor of treatment response in dogs receiving high-flow nasal cannula oxygen therapy

Objective

This study aims to evaluate the respiratory rate-oxygenation index (ROX) and the ratio of pulse oximetry saturation (SpO2) to the fraction of inspired oxygen (FiO2) (SpO2/FiO2, [SF]) to determine whether these indices are predictive of outcome in dogs receiving high-flow nasal cannula oxygen therapy (HFNOT).

Design

This is a prospective observational study.

Setting

This study was carried out at two university teaching hospitals.

Animals

In total, 88 dogs treated with HFNOT for hypoxemic respiratory failure due to various pulmonary diseases were selected.

Measurements and main results

The ROX index was defined as the SF divided by the respiratory rate (RR). ROX and SF were calculated at baseline and for each hour of HFNOT. The overall success rate of HFNOT was 38% (N = 33/88). Variables predicting HFNOT success were determined using logistic regression, and the predictive power of each variable was assessed using the area under the receiver operating curve (AUC). ROX and SF were adequately predictive of HFNOT success when averaged over 0-16 h of treatment, with similar AUCs of 0.72 (95% confidence interval [CI] 0.60-0.83) and 0.77 (95% CI 0.66-0.87), respectively (p < 0.05). SF showed acceptable discriminatory power in predicting HFNOT outcome at 7 h, with an AUC of 0.77 (95% CI 0.61-0.93, p = 0.013), and the optimal cutoff for predicting HFNC failure at 7 h was SF ≤ 191 (sensitivity 83% and specificity 76%).

Conclusion

These indices were easily obtained in dogs undergoing HFNOT. The results suggest that ROX and SF may have clinical utility in predicting the outcomes of dogs on HFNOT. Future studies are warranted to confirm these findings in a larger number of dogs in specific disease populations.

Retrospective evaluation of the respiratory rate-oxygenation index to predict the outcome of high-flow nasal cannula oxygen therapy in dogs (2018-2021): 81 cases

OBJECTIVE

To evaluate the respiratory rate-oxygenation index (ROX), modified ROX index (ROX-HR), and the ratio of pulse oximetry saturation (Spo2) to Fio2 (SF) to determine if these indices over time are predictive of outcome in dogs treated with high-flow nasal cannula oxygen therapy (HFNC).

DESIGN

Retrospective study.

SETTING

Two university teaching hospitals.

ANIMALS

Eighty-one client-owned dogs treated with HFNC for hypoxemic respiratory failure.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The ROX was defined as the SF divided by the respiratory rate (RR), and the ROX-HR was defined as the ROX divided by the heart rate multiplied by 100. The overall success rate of HFNC was 44% (n = 36/81). Dogs weaned from HFNC had a significantly higher ROX (P < 0.0001) at 1-3, 5-10, 12, and 15 hours than dogs that failed HFNC. Both the ROX and SF showed excellent discriminatory power in predicting HFNC failure at 6 hours, with an area under receiver operating curve of 0.85 (95% confidence interval: 0.72-0.99; P < 0.002) and 0.86 (95% confidence interval: 0.73-0.99; P < 0.001), respectively. The optimal cutoff values for predicting HFNC failure at 6 hours were a ROX ≤3.68 (sensitivity 72%, specificity 92%) and an SF ≤143 (sensitivity 79%, specificity 93%).

CONCLUSIONS

These results suggest that similar to people, the ROX and SF are useful predictors of HFNC failure. These indices are easy to measure at the bedside and may have clinical use. Future prospective studies are warranted to confirm the findings and to optimize cutoff values in a larger population of dogs undergoing HFNC.

Proposed protocol for utilising high-flow nasal oxygen therapy in treatment of dogs hospitalised due to pneumonia

BACKGROUND

High-flow nasal oxygen (HFNO) therapy is a non-invasive respiratory support method that provides oxygen-enriched, warmed, and humidified air to respiratory-compromised patients. It is widely used in human medical care, but in veterinary medicine it is still a relatively new method. No practical guidelines exist for its use in canine pneumonia patients, although they could potentially benefit from HFNO therapy. This study aims to provide a new, safe, non-invasive, and effective treatment protocol for oxygen supplementation of non-sedated dogs with pneumonia.

METHODS

Twenty privately owned dogs with pneumonia will receive HFNO therapy at a flow rate of 1-2 L/kg, and the fraction of inspired oxygen will be determined individually (ranging from 21% to 100%). HFNO therapy will continue as long as oxygen support is needed based on clinical evaluation. Patients will be assessed thrice daily during their hospitalisation, with measured primary outcomes including partial pressure of oxygen, oxygen saturation, respiratory rate and type, days in hospital, and survival to discharge.

DISCUSSION

The proposed protocol aims to provide a practical guideline for applying HFNO to dogs hospitalised due to pneumonia. The protocol could enable more efficient and well-tolerated oxygenation than traditional methods, thus hastening recovery and improving survival of pneumonia patients.

Use of high-flow oxygen therapy in a cat with cardiogenic pulmonary edema

Case summary

A 7-month-old female spayed domestic shorthair cat was presented for respiratory distress due to cardiogenic pulmonary edema. Despite initial treatment and oxygen delivery in an oxygen tent, the cat still showed signs of severe respiratory effort and oxygen saturation measured via pulse oximetry was below 85%. Because the owners declined mechanical ventilation, the cat was transitioned to high-flow oxygen therapy (HFOT). HFOT allowed significant improvement of the respiration parameters within 15 mins without causing clinical complications. The cat was briefly anaesthetised for the placement of the nasal cannula on initiation of HFOT, and the interface was well tolerated thereafter. The cat was transitioned to an oxygen cage after 16 h, weaned from oxygen 4 h later and was discharged after 3 days of hospitalisation. Long-term follow-up showed no abnormalities, and the leading hypothesis was transient myocardial thickening.

Relevance and novel information

The first use of HFOT in a dyspneic cat is described in this study. HFOT could be a life-saving option for cats with severe hypoxemia or do-not-intubate orders that fail to respond to conventional oxygen therapies.

Evaluation of Nasal Oxygen Administration at Various Flow Rates and Concentrations in Conscious, Standing Adult Horses

This study evaluated the effects of various flow rates and fractions of oxygen on arterial blood gas parameters and on the fraction of inspired oxygen (F_IO₂) delivered to the distal trachea. Oxygen was administered to 6 healthy, conscious, standing, adult horses via single nasal cannula positioned within the nasopharynx. Three flow rates (5, 15, 30 L/min) and fractions of oxygen (21, 50, 100%) were delivered for 15 minutes, each in a randomized order. F_IO₂ was measured at the level of the nares and distal trachea. Adverse reactions were not observed with any flow rate. F_IO₂ (nares and trachea) and PaO₂ increased with increasing flow rate and fraction of oxygen (P < .0001). F_IO₂ (trachea) was significantly less than F_IO₂ (nares) at 50% and 100% oxygen at all flow rates (P < .0001). Differences in PaO₂ were not observed between 100% oxygen-5L/min and 50% oxygen-15L/min and or between 100% oxygen-15L/min and 50% oxygen-30L/min. Tracheal F_IO₂ for 100% oxygen-15L/min was increased compared to 50% oxygen-30L/min (P < .0001). Respiratory rate, ETCO₂, PaCO₂, and pH did not differ between treatments. Administration of 50% oxygen via nasal cannula at 15 and 30 L/min effectively increased in PaO₂ and was well tolerated in conscious, standing, healthy horses. While these results can be used guide therapy in hypoxemic horses, evaluation of the administration of 50% oxygen to horses with respiratory disease is warranted.

The use of High-Flow Nasal Oxygen Therapy in 4 dogs undergoing bronchoscopy

Introduction

High-Flow Nasal Oxygen Therapy is a method to deliver warmed, humidified air-oxygen blended at high flow rates to patients through a nasal cannula using a specialized, commercially available machine. This is a well-tolerated, safe and effective method for oxygen delivery to healthy and hypoxemic dogs. Patients undergoing bronchoscopic procedures frequently develop hypoxemia. Human trials have shown a reduction in incidents of hypoxemic events and higher pulse oximeter oxygen saturation during bronchoscopies in patients on High-Flow Nasal Oxygen.

Materials and methods

This is a single-centre, prospective case series. All dogs weighing between 5 and 15 kg and undergoing bronchoscopy during the study period (03/07/2022-01/10/2022) were eligible.

Results

Twelve patients were eligible for inclusion of which four were enrolled. No clinically significant complications related to the use of High-Flow Nasal Oxygen Therapy were recorded. Two of the patients were re-intubated post bronchoscopy due to clinician preference for recovery. One of the patients had a self-limiting period of severe hypoxemia with a pulse oximeter oxygen saturation of 84% for &lt; 1 min during bronchoalveolar lavage, and whilst undergoing High-Flow Nasal Oxygen administration. Another patient had a self-limiting episode of mild hypoxemia (SpO2 of 94% lasting &lt; 1 min) 5 min after completion of bronchoalveolar lavage.

Conclusion

No clinically relevant complications relating to High-Flow Nasal Oxygen Therapy were recorded in this case series, although further studies are required to confirm this conclusion. This initial data suggests that the use of High-Flow Nasal Oxygen therapy during bronchoscopy is feasible and potentially safe, although it may not prevent hypoxemia in these patients. The use of High-Flow Nasal Oxygen Therapy during bronchoscopy in small patients carries multiple potential benefits and further studies to compare its efficacy against other traditional oxygen delivery systems are warranted in this patient population.

Noncardiogenic pulmonary edema in small animals

OBJECTIVE

To review various types of noncardiogenic pulmonary edema (NCPE) in cats and dogs.

ETIOLOGY

NCPE is an abnormal fluid accumulation in the lung interstitium or alveoli that is not caused by cardiogenic causes or fluid overload. It can be due to changes in vascular permeability, hydrostatic pressure in the pulmonary vasculature, or a combination thereof. Possible causes include inflammatory states within the lung or in remote tissues (acute respiratory distress syndrome [ARDS]), airway obstruction (post-obstructive pulmonary edema), neurologic disease such as head trauma or seizures (neurogenic pulmonary edema), electrocution, after re-expansion of a collapsed lung or after drowning.

DIAGNOSIS

Diagnosis of NCPE is generally based on history, physical examination, and diagnostic imaging. Radiographic findings suggestive of NCPE are interstitial to alveolar pulmonary opacities in the absence of signs of left-sided congestive heart failure or fluid overload such as cardiomegaly or congested pulmonary veins. Computed tomography and edema fluid analysis may aid in the diagnosis, while some forms of NCPE require additional findings to reach a diagnosis.

THERAPY

The goal of therapy for all types of NCPE is to preserve tissue oxygenation and reduce the work of breathing. This may be achieved by removing the inciting cause (eg, airway obstruction) and cage rest in mild cases and supplemental oxygen in moderate cases and may require mechanical ventilation in severe cases.

PROGNOSIS

Prognosis is generally good for most causes of veterinary NCPE except for ARDS, although data are scarce for some etiologies of NCPE.

Clinical review of high-flow nasal oxygen therapy in human and veterinary patients

Oxygen therapy is the first-line treatment for hypoxemic acute respiratory failure. In veterinary medicine this has traditionally been provided via mask, low-flow nasal oxygen cannulas, oxygen cages and invasive positive pressure ventilation. Traditional non-invasive modalities are limited by the maximum flow rate and fraction of inspired oxygen (FiO₂) that can be delivered, variability in oxygen delivery and patient compliance. The invasive techniques are able to provide higher FiO₂ in a more predictable manner but are limited by sedation/anesthesia requirements, potential complications and cost. High-flow nasal oxygen therapy (HFNOT) represents an alternative to conventional oxygen therapy. This modality delivers heated and humidified medical gas at adjustable flow rates, up to 60 L/min, and FiO₂, up to 100%, via nasal cannulas. It has been proposed that HFNOT improves pulmonary mechanics and reduces respiratory fatigue via reduction of anatomical dead space, provision of low-level positive end-expiratory pressure (PEEP), provision of constant FiO₂ at rates corresponding to patient requirements and through improved patient tolerance. Investigations into the use of HFNOT in veterinary patients have increased in frequency since its clinical use was first reported in dogs with acute respiratory failure in 2016. Current indications in dogs include acute respiratory failure associated with pulmonary parenchymal disease, upper airway obstruction and carbon monoxide intoxication. The use of HFNOT has also been advocated in certain conditions in cats and foals. HFNOT is also being used with increasing frequency in the treatment of a widening range of conditions in humans. Although there remains conflict regarding its use and efficacy in some patient groups, overall these reports indicate that HFNOT decreases breathing frequency and work of breathing and reduces the need for escalation of respiratory support. In addition, they provide insight into potential future veterinary applications. Complications of HFNOT have been rarely reported in humans and animals. These are usually self-limiting and typically result in lower morbidity and mortality than those associated with invasive ventilation techniques.

High-flow nasal cannula improves hypoxemia in dogs failing conventional oxygen therapy

OBJECTIVE

A prospective clinical trial was performed to evaluate the efficacy and tolerance of high-flow nasal cannula (HFNC) in dogs with hypoxemia.

ANIMALS

20 client-owned dogs failing conventional oxygen therapy (COT).

PROCEDURES

Patients admitted to the ICU for treatment of hypoxemic respiratory failure were enrolled in the study. PaO2, SPO2, respiratory rate (RR), and acute patient physiologic and laboratory evaluation scores were obtained at the time of COT failure and after initiation of HFNC. Complications and patient tolerance while receiving HFNC were also recorded.

RESULTS

Compared to COT, the median PaO2 and SO2 were significantly higher when dogs were receiving HFNC (60.8 vs 135.6 mm Hg and 90.7% vs 99.25%, respectively). Dogs receiving HFNC had a significant reduction in median RR as compared to dogs undergoing COT (52 vs 36 breaths per minute). After the initiation of HFNC, all dogs showed clinical improvement as measured by PaO2, SO2, and RR. Of 20 dogs, 6 ultimately failed HFNC and mechanical ventilation was recommended. Nine dogs undergoing HFNC survived to discharge, and acute patient physiologic and laboratory evaluation scores had a significant positive severity correlation with death. Complications included pneumothorax in 1 dog.

CLINICAL RELEVANCE

COT has limited flow rates due to airway irritation caused by room temperature, nonhumidified oxygen. HFNC uses vapor humidification and heated oxygen, allowing for higher flow rates. In people, HFNC is used as escalation of oxygen therapy when COT fails. Dogs treated with HFNC had significant improvements in PaO2, SO2, and RR as compared to COT. HFNC is well tolerated and effective in treating hypoxemia in dogs.

A Review of High Flow Nasal Cannula Oxygen Therapy in Human and Veterinary Medicine

Respiratory distress is a common ailment in small animal medicine. Oxygen supplementation is a mainstay of initial therapy. High Flow Nasal Cannula Oxygen Therapy (HFNCOT) has become increasingly popular as a treatment modality in human medicine, and more recently in canine patients. These devices deliver high flow rates of heated and humidified oxygen at an adjustable fraction of inspired oxygen (FiO₂). This article reviews current literature in human patients on HFNCOT as well as studies that have evaluated its use in veterinary patients. A discussion of the respiratory physiology that is associated with respiratory distress, in addition to an overview of currently available oxygen supplementation modalities is provided. The physiologic benefits of HFNCOT are explained, as are technical aspects associated with its use. Recommendations on initial settings, maintenance therapy, and weaning are also described.

Nasal high flow oxygen therapy in hospitalised neonatal foals

BACKGROUND

Respiratory disease is common in critically ill neonatal foals. Traditional oxygen therapy (TOT) with nasal insufflation of oxygen is often used to provide first-line respiratory support. Mechanical ventilation is used in foals which require a greater level of support but requires specialist expertise and can be associated with significant complications. Non-invasive ventilation (NIV) enables a greater level of respiratory support without the need for intubation. High flow oxygen therapy (HFOT) is a mode of NIV commonly used in human intensive care.

OBJECTIVES

To describe the use of HFOT in hospitalised neonatal foals.

STUDY DESIGN

Retrospective case series.

METHODS

Hospital records of neonatal foals admitted between 2018 and 2019 that received treatment with HFOT were reviewed. Clinical data and complications were recorded.

RESULTS

Fourteen foals were identified and the median duration of use was 43 hours (range 2-93 hours) with a median flow rate of 0.7L/kg/min (range 0.42-1.67). Ten foals survived to discharge. No significant complications associated with the technique were recorded.

MAIN LIMITATIONS

A small study population which was retrospectively reviewed.

CONCLUSIONS

This study provides preliminary information about the clinical use of HFOT in neonatal foals. The technique was well tolerated and no significant adverse effects were noted. However, further study is required to evaluate efficacy.

Cardiopulmonary (No Ventilation) and Anesthetic Effects of Dexmedetomidine-Tiletamine in Dogs

The aim of the present study was to evaluate the anesthetic and cardiopulmonary effects of dexmedetomidine in combination with tiletamine (without zolazepam) as a general anesthetic. The study was divided into two phases. In Phase 1, 18 adult healthy mixed-breed dogs were randomly allocated into three groups: Group TD8 (4.5 mg kg⁻¹ tiletamine and 8 μg kg⁻¹ dexmedetomidine), Group TD10 (4.5 mg kg⁻¹ tiletamine and 10 μg kg⁻¹ dexmedetomidine), or Group TD12 (4.5 mg kg⁻¹ tiletamine and 12 μg kg⁻¹ dexmedetomidine). After drug administration, the heart rate (HR), respiratory rate (f_R), mean arterial pressure (MAP), systolic arterial pressure (SAP), diastolic arterial pressure (DAP), peripheral hemoglobin oxygen saturation (SpO₂), behavioral score, quality of induction and recovery, extent of ataxia, the time taken for induction, and the duration of anesthesia were recorded. The recovery time and quality were recorded after administration of atipamezole (50 μg kg⁻¹) after 60 min. In phase 2, the feasibility of combining dexmedetomidine (10 μg kg⁻¹) and tiletamine (4.5 mg kg⁻¹) as general anesthetics for orchiectomy was evaluated in dogs (n = 6). HR, f_R, MAP, SAP, DAP, temperature, SpO₂, behavioral scores, and adverse reactions were recorded during each surgical procedure. In phase 1, the dogs were anesthetized for 5 min after administration of drugs and achieved a maximum behavioral score in TD10 and TD12 after 10 min. Although HR, MAP, SAP, DAP, and NIBP decreased in all three groups, they still maintained within the normal range. In phase 2, orchiectomy was completed smoothly in all dogs with little fluctuation in the physiological variables. We found that a combination of tiletamine (4.5 mg kg⁻¹) and dexmedetomidine (10 μg kg⁻¹) intramuscularly induced moderate anesthesia in dogs and could be utilized for short-term anesthesia and minor surgery.

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

OBJECTIVES

To prospectively describe the impact of gas flow rate and temperature on dog's tolerance of high-flow nasal oxygen therapy during recovery from anaesthesia, hypothesizing that higher flow rates and temperatures will decrease tolerance.

MATERIALS AND METHODS

Twelve non-dyspnoeic client-owned dogs recovering from general anaesthesia were included in this study. After extubation, a nasal cannula was positioned and high-flow nasal oxygen therapy was initiated. Two flow rates (two or four time the theoretical minute ventilation: HF2 and HF4), each of them combined with two temperatures (31 and 37°C: T31 and T37), were randomly applied (four conditions per dog). For each condition, cardiovascular and respiratory parameters (heart rate, respiratory rate, systolic arterial blood pressure and pulse oximeter oxygen saturation), sedation score and tolerance score were recorded at initiation (T₀ ) and after 10 minutes of accommodation (T₁₀ ).

RESULTS

Sedation scores were not significantly different between the four conditions. Cardiovascular and respiratory parameters were not significantly different between any condition at both T₀ and T₁₀ . Tolerance scores were good and not significantly different between any flow rate or temperature (HF2-T31: 4 (2-4), HF4-T31: 4 (2-4), HF2-T37: 4 (2-4), HF4-T37: 4 (1-4)).

CLINICAL SIGNIFICANCE

The gas flow rates and temperatures studied have no impact on tolerance during the recovery period of non-dyspnoeic dogs, and high-flow nasal cannula is well tolerated. Further studies are required to confirm these results in dyspnoeic dogs.

Respiratory Emergencies

Respiratory distress is commonly seen in dogs and cats presenting to the emergency room. Rapid identification of respiratory difficulty with strategic stabilization and diagnostic efforts are warranted to maximize patient outcome. This article focuses on the relevant anatomy and physiology of the respiratory system and the clinical recognition, stabilization, and initial diagnostic planning for small animal patients that present for respiratory emergencies.

High-flow nasal cannula oxygen therapy in acute hypoxemic respiratory failure in 22 dogs requiring oxygen support escalation

OBJECTIVE

To determine the effect of high-flow nasal cannula (HFNC) oxygen therapy on cardiorespiratory variables and outcome in dogs with acute hypoxemic respiratory failure.

DESIGN

Prospective, sequential clinical trial.

SETTING

University veterinary teaching hospital.

ANIMALS

Twenty-two client-owned dogs that failed to respond to traditional oxygen support.

INTERVENTIONS

Initiation of HFNC therapy after traditional oxygen supplementation failed to increase Spo₂ > 96% and Pao₂ > 75 mm Hg or improve respiratory rate/effort.

MEASUREMENTS AND MAIN RESULTS

Physiological variables, blood gas analyses, and dyspnea/sedation/tolerance scores were collected prior to HFNC initiation (on traditional oxygen support [time 0 or T0]), and subsequently during HFNC oxygen administration at time 30 minutes, 60 minutes, and 7 ± 1 hours. Relative to T0, use of HFNC resulted in a decreased respiratory rate at 1 hour (P = 0.022) and 7 hours (P = 0.012), a decrease in dyspnea score at all times (P < 0.01), and an increase in Spo₂ at all times (P < 0.01). There was no difference in arterial/venous Pco₂ relative to T0, although Paco₂ was correlated with flow rate. Based on respiratory assessment, 60% of dogs responded to HFNC use by 30 minutes, and 45% ultimately responded to HFNC use and survived. No clinical air-leak syndromes were observed.

CONCLUSIONS

HFNC use improved oxygenation and work of breathing relative to traditional oxygen therapies, without impairing ventilation. HFNC use appears to be a beneficial oxygen support modality to bridge the gap between standard oxygen supplementation and mechanical ventilation.

Preliminary evaluation of the use of high-flow nasal cannula oxygen therapy during recovery from general anesthesia in dogs with obstructive upper airway breathing

BACKGROUND

Brachycephalic airway syndrome can pose a risk of complicated recovery from anesthesia as a result of irritation to the excess pharyngeal andlaryngeal tissue present in affected dogs. High-flow nasal cannula (HFNC) oxygen therapy is a respiratory support modality that offers provision of continuous positive airway pressure via high gas flow rates. The HFNC system actively warms and humidifies inspired gases, which improves comfort and facilitates tolerance of the high flow rates in people and dogs. HFNC oxygen therapy was applied to brachycephalic dogs that developed increased work of breathing or hypoxemia in the recovery phase of anesthesia to determine if this device would be tolerable and effective for relief of upper respiratory difficulty.

KEY FINDINGS

The HFNC nasal prong interface is well suited to the brachycephalic facial structure. The application of HFNC was found to reduce dyspnea scores in patients with signs of upper airway obstruction after general anesthesia. Aerophagia and changes in PCO₂ were noted.

SIGNIFICANCE

Application of HFNC in the recovery period may result in improved airflow during times of somnolent obstructive breathing, not unlike the use of continuous positive airway pressure therapy in sleep-disordered breathing in people.

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

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.