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

High-velocity nasal insufflation in dogs with left-sided congestive heart failure unresponsive to traditional oxygen therapy: a retrospective case series

Objective

To describe high-velocity nasal insufflation (HVNI) for managing dogs with left-sided congestive heart failure (L-CHF) failing traditional oxygen therapy (TOT). To secondarily evaluate complications based on retrospective evaluation of the record of HVNI and survival to discharge.

Design

Retrospective case series from a university teaching hospital between August 2019 and October 2021.

Animals

Twelve dogs diagnosed with L-CHF and managed with HVNI.

Measurements and main results

Medical records were retrospectively reviewed for signalment, point-of-care diagnostics, and HVNI information. Nine dogs were diagnosed with myxomatous mitral valve disease, and three dogs were diagnosed with dilated cardiomyopathy. All dogs in this study required HVNI after failing TOT. Dogs were treated with HVNI for a median of 14 h (range 2-22 h). HVNI was successfully discontinued in 10 dogs (83%), all of which survived to discharge. Two dogs on HVNI were humanely euthanized, both of which were diagnosed with Stage D refractory CHF. No major complications of HVNI were noted in any dogs.

Conclusion

HVNI is a potential method of escalating oxygen support for dogs in L-CHF who fail TOT. In this case series, all dogs in which HVNI was successfully discontinued survived to discharge.

High-flow vs conventional oxygen therapies for acute cardiogenic pulmonary edema following hip fractures and surgery in elderly patients

Purpose

This prospective, randomized controlled study aimed to compare the effects of high-flow oxygen therapy and conventional oxygen therapy in the treatment of acute cardiogenic pulmonary edema following hip fractures and surgery in elderly patients.

Methods

From February 2018 to October 2023, 124 patients diagnosed with acute cardiogenic pulmonary edema following hip fractures and surgery were randomly assigned to the high-flow oxygen therapy group (n=62) or conventional oxygen therapy group (n=65). Partial pressure of oxygen (PO2) and blood oxygen saturation (SPO2) were assessed 60 minutes after the treatments. A P value <0.05 was considered statistically significant.

Results

There were significant differences in PO2 (66.2 ± 3.3 mmHg vs 62.1 ± 3.4 mmHg, P<0.05) and SPO2 (97.8 ± 2.1 mmHg vs 94.2 ± 1.7 mmHg, P<0.05) between the groups.

Conclusion

In the treatment of elderly patients with ACPE following hip fractures and surgery, high-flow oxygen therapy may be performed to improve ventilation when acute cardiogenic pulmonary edema does not significantly improve within 15 minutes of conventional oxygen therapy.

Retrospective Evaluation of the Correlation Between Pa2:FiO2 and SpO2 Ratios in Dogs Undergoing High-Flow Nasal Cannula Oxygen Therapy

BACKGROUND

In veterinary medicine, high-flow nasal cannula oxygen therapy (HFNT) has gained popularity in managing hypoxemic respiratory failure, bridging the gap between conventional oxygen therapy and mechanical ventilation. The SpO2:FiO2 (SF) ratio could be useful in assessing oxygenation impairment in dogs undergoing HFNT. The current study aimed to determine whether the SF ratio correlates with the PaO2:FiO2 (PF) ratio in dogs undergoing HFNT.

KEY FINDINGS

A total of 30 data pairs with concurrent SpO2 and PaO2 measurements were identified from 19 dogs treated with HFNT from two university veterinary teaching hospitals. PF and SF ratios were measured when PaO2 fell between 74 and 129 mm Hg. The median SF and PF ratios were 186 (interquartile range: 97-243) and 168 (interquartile range: 108-297), respectively. SF ratios were strongly correlated with PF ratios (rho = 0.86 [95% confidence interval: 0.73-0.93], P < 0.001, weighted r = 0.89 [95% confidence interval: 0.74-0.96]).

SIGNIFICANCE

Preliminary results suggest a statistically significant positive correlation between SF and PF ratios in dogs treated with HFNT. This study provides data that can be used to calculate appropriate sample sizes for subsequent studies investigating the specific SF ratios corresponding with the PF ratios as the criteria for assessing hypoxemia.

Postural drainage and high flow nasal oxygen therapy in four cats with decompensated cardiogenic pulmonary oedema

CASE SERIES SUMMARY

This case series describes four cats with decompensated congestive heart failure and fulminant cardiogenic pulmonary oedema (CPE) that did not respond to conventional treatment and oxygen therapy, and subsequently developed hypoxaemic respiratory failure. The cats were anaesthetised to enable endotracheal intubation, manually ventilated with 100% oxygen and postural drainage was performed immediately to evacuate pulmonary oedema. Afterwards, the cats were extubated and transitioned to high-flow nasal oxygen (HFNO). HFNO allowed significant improvement in the respiration parameters without causing clinical complications. In three of the cats, the procedure was successful; duration of HFNO ranged between 4 and 44 h, and they were successfully weaned off the HFNO therapy. One cat required re-intubation due to HFNO-response failure and was ultimately euthanased. Another cat was euthanased 5 days later due to the severity of its underlying disease.

RELEVANCE AND NOVEL INFORMATION

This is the first report describing the combined technique of postural drainage and HFNO in cats with decompensated CPE. This combined technique could be a life-saving option for cats that fail to respond to conventional therapies and for which positive pressure ventilation is not an option.

Intravenous anesthesia with high-flow nasal cannula improves recovery in elderly undergoing ureteroscopic lithotripsy: a prospective controlled study

BACKGROUND

Intravenous anesthesia with high-flow nasal cannula (HFNC) has been reported to benefit oxygen reserves and enhance postoperative recovery in surgeries requiring low neuromuscular blockade. This study investigated whether HFNC improves recovery quality in elderly undergoing ureteroscopic holmium laser lithotripsy (UHLL).

METHODS

We enrolled 106 elderly patients undergoing UHLL, with 96 patients (48 per group) included in the final analysis. Patients were randomly assigned (1:1, stratified by sex) to receive either HFNC (HFNC group) or laryngeal mask airway (LMA) assisted general anesthesia (LMA group). The primary outcome was the Quality of Recovery 15-questionnaire (QoR-15) scores. Secondary outcomes included PACU stay duration, time to out-of-bed mobilization, length of hospital stay, airway dryness scores, surgeons' satisfaction, and postoperative complications.

RESULTS

Compared to the LMA group, the HFNC group achieved significantly higher QoR-15 scores (125.5 [118.3-130.0] vs. 136.5 [126.3-139.0]; difference = -9, 95%CI, -11 to -5; P < 0.001) on the first postoperative day. For secondary outcomes, the HFNC group had a shorter PACU stay (difference = 11.6 min, 95% CI, 10.4-12.8 min), earlier out-of-bed mobilization (difference = 31.8 min, 95% CI, 30.6-33.1 min), lower mouth (difference = 2, 95% CI, 1-3) and throat dryness scores (difference = 2, 95% CI, 1-3) at 30 min post-operation, and lower rates of postoperative sore throat (14.6% vs. 0%; P = 0.019) and cough with sputum (odds ratio [OR] = 9.4, 95% CI, 1.1-78.4). No significant differences were observed between the groups for other measures.

CONCLUSIONS

HFNC can improve recovery quality in elderly patients after UHLL compared to LMA-assisted general anesthesia.

TRIAL REGISTRATION

This trial was registered on July 20, 2023, in the Chinese Clinical Trial Registry (ChiCTR2300073757).

A Comprehensive Review on High-Flow Nasal Cannula Oxygen Therapy in Critical Care: Evidence-Based Insights and Future Directions

High-flow nasal cannula (HFNC) therapy has emerged as a significant advancement in respiratory support, offering a non-invasive alternative to traditional oxygen delivery methods in critical care settings. This review comprehensively evaluates HFNC therapy, focusing on its definition, historical evolution, and current clinical applications. HFNC therapy delivers humidified and heated oxygen at high flow rates through a nasal cannula, enhancing oxygenation and patient comfort. The review highlights the physiological mechanisms underlying HFNC and its efficacy in managing acute respiratory failure, chronic obstructive pulmonary disease exacerbations, and postoperative respiratory support. Key findings from clinical trials and meta-analyses are discussed, emphasizing HFNC's advantages over conventional methods, such as reduced intubation rates and shorter ICU stays. The review also addresses safety considerations, including potential risks and complications associated with HFNC therapy. Furthermore, it explores future directions for research and technological advancements aimed at optimizing HFNC use in diverse patient populations. This review aims to provide evidence-based insights to inform clinical practice and guide future investigations in respiratory therapy.

High-flow nasal cannula oxygen therapy in seven cats with respiratory failure

CASE SERIES SUMMARY

This case series describes seven cats that were treated with high-flow nasal cannula oxygen therapy (HFNOT). Seven cats were prospectively (n = 5) or retrospectively (n = 2) included from three veterinary university referral centers between March 2020 and September 2023. Data on signalment, medical history, clinical and diagnostic findings, treatment administered, response to HFNOT and outcomes were recorded. All cats included in this case series failed to respond to oxygen cage or flow-by oxygen therapy and were subsequently transitioned to HFNOT. After this transition, these cats demonstrated a marked improvement in respiratory parameters, including respiratory rate, effort and oxygen saturation measured by pulse oximetry, within 1 h of initiating HFNOT. All cats tolerated HFNOT well without any complications.

RELEVANCE AND NOVEL INFORMATION

There is limited literature reporting the use of HFNOT in feline patients. This is the first case series in the literature of HFNOT utilized as an advanced oxygen delivery method for feline respiratory failure. This case series indicates that HFNOT improves oxygenation in feline patients that fail to respond to conventional oxygen therapy.

Case series of dogs with blastomycosis managed with high-flow nasal oxygen therapy (2019-2023): 19 cases

Objective

To describe the clinical presentation, progression, treatment, and outcome of dogs with blastomycosis treated with high-flow nasal oxygen therapy (HFNOT).

Design

Retrospective case review.

Setting

University veterinary teaching hospital.

Animals

Nineteen client-owned dogs with strongly suspected or confirmed blastomycosis treated with HFNOT.

Measurements and main results

The medical records of dogs with strongly suspected or confirmed blastomycosis between October 2019 and May 2023 that received HFNOT were evaluated. Nineteen dogs were included. Nine dogs were started directly on high-flow nasal oxygen therapy. The remaining 10 dogs first received traditional oxygen therapy and were then transitioned to HFNOT 3-142 h later. Of the 19 dogs, 1 survived to discharge from hospital, 12 were euthanized due to progression of disease, and 6 died during the hospitalization period.

Conclusions and clinical importance

The prognosis for survival of dogs with severe blastomycosis requiring therapy beyond traditional oxygen methods was poor to grave in this population. This is the first known documented report of HFNOT use in dogs with confirmed or suspected blastomycosis.

High flow oxygen therapy versus conventional oxygen therapy in dogs and cats undergoing bronchoscopy and bronchoalveolar lavage: a pilot study

Objectives

To evaluate the safety and feasibility of high flow oxygen therapy (HFOT), and to record SpO2 and desaturation episodes in dogs and cats receiving HFOT or conventional oxygen therapy (COT) during bronchoscopy ± bronchoalveolar lavage (BAL).

Materials and methods

Dogs and cats undergoing bronchoscopy ± BAL between January and May 2023 were included in the study. Patients were randomly allocated to two groups: HFOT (HFOT group; two cats and four dogs) and COT (COT group; one cat and five dogs). HFOT and COT were started at the beginning of the bronchoscopy. HFOT was delivered with a gas flow rate of 1 L/kg/min at an FiO2 of 100% and a temperature of 34°C (pediatric mode) or 37°C (adult mode). COT was delivered through the working channel of the bronchoscope at a rate of 1.5 L/min. The safety and feasibility of HFOT were assessed, and peripheral oxygen saturation (SpO2) was measured by pulse oximetry every 30 s throughout the procedure.

Measurements and main results

HFOT was feasible and safe in both dogs and cats with no complications reported. While there was no significant difference in the number of desaturation episodes (SpO2 < 94%) between the two groups, none of the patients in the HFOT group experienced severe desaturation (SpO2 < 90%). In contrast, two patients in the COT group had an SpO2 < 90%. Mean SpO2 was significantly higher in the HFOT group compared to the COT group at T0 (98% ± 2% vs. 94 ± 2%), T0.5 (98% ± 2% vs. 94% ± 3%) and T1 (98% ± 2% vs. 94% ± 4%).

Conclusion

To the authors' knowledge, this is the largest study conducted to date using HFOT during bronchoscopy in dogs and cats. Our results suggest that HFOT is feasible and safe during bronchoscopy ± BAL. Furthermore, HFOT may reduce the risk of desaturation episodes in dogs and cats undergoing bronchoscopy and BAL.

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.

Respiratory Effects of Continuous Positive Airway Pressure Administered during Recovery from General Anesthesia in Brachycephalic Dogs

This study aimed to evaluate the benefits of applying 5 cmH2O of CPAP using a pediatric helmet during the recovery phase from general anesthesia in brachycephalic dogs. Brachycephalic dogs undergoing various surgical procedures were included in this study, and a total of 64 subjects were randomly assigned to receive either standard oxygen supplementation (NO-CPAP group) or oxygen supplementation combined with CPAP (CPAP group). This study evaluated arterial blood pH, blood gas partial pressures of O2 and CO2, arterial blood O2 saturation, and related parameters during recovery. The dogs were monitored, and helmet tolerance was assessed using predefined criteria. Of the initially assessed 69 dogs, 64 were enrolled: 32 in the CPAP group and 32 in the NO-CPAP group. Fifteen dogs in the NO-CPAP group were excluded based on predetermined criteria. The CPAP group showed significant improvements in PaO2, PaO2/FiO2, P(A-a)O2, F-Shunt, and respiratory rate compared with the NO-CPAP group (p < 0.001). The incidence of reintubation and helmet intolerance was higher in the NO-CPAP group (18% and 15.6%, respectively) than in the CPAP group (0%). This study highlights the potential benefits of incorporating CPAP, delivered through a pediatric helmet, in the perioperative management of brachycephalic dogs.

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.