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 Experts on Air

Intubating patients in hypoxemic respiratory failure. Does time matter?

Webinar #4

Q&A Webinar #4.

Many observational studies have suggested that NHF prevents intubation. The clinical impression was unequivocally demonstrated in a large randomized trial (Frat JP, Thille AW, Mercat A, et al. High-flow oxygen through nasal cannula in acute hypoxemic respiratory failure. N Engl J Med. 2015;372(23):2185-2196. doi:10.1056/NEJMoa15033261​). In this study, patients at greater risk of intubation (i.e., those with PaO2/FiO2 below 200) and who received NHF were significantly less intubated than those who received either NIV or standard oxygen. More recently, several studies performed in Covid-related ARDS have confirmed the prevention of intubation with the use of NHF (COVID-ICU group, for the REVA network, COVID-ICU investigators. Benefits and risks of noninvasive oxygenation strategy in COVID-19: a multicenter, prospective cohort study (COVID-ICU) in 137 hospitals. Crit Care. 2021;25(1):421. Published 2021 Dec 8. doi:10.1186/s13054-021-03784-22​, ​Ospina-Tascón GA, Calderón-Tapia LE, García AF, et al. Effect of High-Flow Oxygen Therapy vs Conventional Oxygen Therapy on Invasive Mechanical Ventilation and Clinical Recovery in Patients With Severe COVID-19: A Randomized Clinical Trial [published correction appears in JAMA. 2022 Mar 15;327(11):1093]. JAMA. 2021;326(21):2161-2171. doi:10.1001/jama.2021.207143​).

Of note, the data is less conclusive in patients with hematological or oncological disorders.
 

If the question is interpreted as "Is it reasonable to start NHF and perhaps escalate to invasive ventilation in a patient beyond 65 years", the answer is yes, but patients and family must be informed that the prognosis is much less favorable than in younger patients. My bias is that intubation should be discussed on an individual basis above 70-75, depending on the presence of comorbodities and the fitness of the patient before being infected by Covid.

Yes, for at least two reasons. First, although there is - at a cohort level - a relationship between the importance of lung involvement and outcome, on an individual basis, we have sometimes had very rapid recovery despite an initial unfavorable radiological assessment. Second, the radiological phenotype also plays a role (we had the impression that very diffuse ground glass was less "bad" than consolidation display). And finally, even if the patient is at high risk of intubation, NHF can be initiated and will help preoxygenate the patient, and will serve as apneic oxygenation during laryngoscopy.  

I don't yet have any personal experience with 100 l/min. My bias is that because there is a linear relationship between flow and both positive pressure and deadspace washout, this suggests that beneficial effects of NHF are more important at 100 l/min than at 60. Obviously, the question of tolerance is a key issue. We need more data on the tolerance of these very high flows.

This is a vast question and whole consensus conferences have been dedicated to this unique question. Bear in mind several facts: 1) there is no 100%-sure test or group of parameters that predict safe extubation; 2) reintubation will occur in 10%-20% of patients; 3) unplanned extubation does not systematically lead to reintubation (only 40% approx.). That means we as clinicians must stay very humble as to our capacity to predict extubation outcome. Always perform either a T-piece trial or minimal pressure support spontaneous breathing trial. When to start these trials? Partial or complete resolution of the cause that led to intubation. Hemodynamic stability without vasopressors, FiO2 < 40%, PEEP < 5, no or little neurological and cognitive impairment, appropriate cough, no or little muscle weakness. 

Disclaimer

The contents of this page are for informational purposes only and are not intended to be a substitute for professional training or for standard treatment guidelines in your facility. The responses to the questions on this page were prepared by the respective webinar's speaker;  any recommendations made here with respect to clinical practice or the use of specific products, technology, or therapies represent the personal opinion of the speaker only, and may not be considered as official recommendations made by Hamilton Medical AG. Hamilton Medical AG provides no warranty with respect to the information contained ion this page and reliance on any part of this information is solely at your own risk.

High-flow oxygen through nasal cannula in acute hypoxemic respiratory failure.

Frat JP, Thille AW, Mercat A, et al. High-flow oxygen through nasal cannula in acute hypoxemic respiratory failure. N Engl J Med. 2015;372(23):2185-2196. doi:10.1056/NEJMoa1503326



BACKGROUND

Whether noninvasive ventilation should be administered in patients with acute hypoxemic respiratory failure is debated. Therapy with high-flow oxygen through a nasal cannula may offer an alternative in patients with hypoxemia.

METHODS

We performed a multicenter, open-label trial in which we randomly assigned patients without hypercapnia who had acute hypoxemic respiratory failure and a ratio of the partial pressure of arterial oxygen to the fraction of inspired oxygen of 300 mm Hg or less to high-flow oxygen therapy, standard oxygen therapy delivered through a face mask, or noninvasive positive-pressure ventilation. The primary outcome was the proportion of patients intubated at day 28; secondary outcomes included all-cause mortality in the intensive care unit and at 90 days and the number of ventilator-free days at day 28.

RESULTS

A total of 310 patients were included in the analyses. The intubation rate (primary outcome) was 38% (40 of 106 patients) in the high-flow-oxygen group, 47% (44 of 94) in the standard group, and 50% (55 of 110) in the noninvasive-ventilation group (P=0.18 for all comparisons). The number of ventilator-free days at day 28 was significantly higher in the high-flow-oxygen group (24±8 days, vs. 22±10 in the standard-oxygen group and 19±12 in the noninvasive-ventilation group; P=0.02 for all comparisons). The hazard ratio for death at 90 days was 2.01 (95% confidence interval [CI], 1.01 to 3.99) with standard oxygen versus high-flow oxygen (P=0.046) and 2.50 (95% CI, 1.31 to 4.78) with noninvasive ventilation versus high-flow oxygen (P=0.006).

CONCLUSIONS

In patients with nonhypercapnic acute hypoxemic respiratory failure, treatment with high-flow oxygen, standard oxygen, or noninvasive ventilation did not result in significantly different intubation rates. There was a significant difference in favor of high-flow oxygen in 90-day mortality. (Funded by the Programme Hospitalier de Recherche Clinique Interrégional 2010 of the French Ministry of Health; FLORALI ClinicalTrials.gov number, NCT01320384.).

Benefits and risks of noninvasive oxygenation strategy in COVID-19: a multicenter, prospective cohort study (COVID-ICU) in 137 hospitals.

COVID-ICU group, for the REVA network, COVID-ICU investigators. Benefits and risks of noninvasive oxygenation strategy in COVID-19: a multicenter, prospective cohort study (COVID-ICU) in 137 hospitals. Crit Care. 2021;25(1):421. Published 2021 Dec 8. doi:10.1186/s13054-021-03784-2



RATIONAL

To evaluate the respective impact of standard oxygen, high-flow nasal cannula (HFNC) and noninvasive ventilation (NIV) on oxygenation failure rate and mortality in COVID-19 patients admitted to intensive care units (ICUs).

METHODS

Multicenter, prospective cohort study (COVID-ICU) in 137 hospitals in France, Belgium, and Switzerland. Demographic, clinical, respiratory support, oxygenation failure, and survival data were collected. Oxygenation failure was defined as either intubation or death in the ICU without intubation. Variables independently associated with oxygenation failure and Day-90 mortality were assessed using multivariate logistic regression.

RESULTS

From February 25 to May 4, 2020, 4754 patients were admitted in ICU. Of these, 1491 patients were not intubated on the day of ICU admission and received standard oxygen therapy (51%), HFNC (38%), or NIV (11%) (P < 0.001). Oxygenation failure occurred in 739 (50%) patients (678 intubation and 61 death). For standard oxygen, HFNC, and NIV, oxygenation failure rate was 49%, 48%, and 60% (P < 0.001). By multivariate analysis, HFNC (odds ratio [OR] 0.60, 95% confidence interval [CI] 0.36-0.99, P = 0.013) but not NIV (OR 1.57, 95% CI 0.78-3.21) was associated with a reduction in oxygenation failure). Overall 90-day mortality was 21%. By multivariable analysis, HFNC was not associated with a change in mortality (OR 0.90, 95% CI 0.61-1.33), while NIV was associated with increased mortality (OR 2.75, 95% CI 1.79-4.21, P < 0.001).

CONCLUSION

In patients with COVID-19, HFNC was associated with a reduction in oxygenation failure without improvement in 90-day mortality, whereas NIV was associated with a higher mortality in these patients. Randomized controlled trials are needed.

Effect of High-Flow Oxygen Therapy vs Conventional Oxygen Therapy on Invasive Mechanical Ventilation and Clinical Recovery in Patients With Severe COVID-19: A Randomized Clinical Trial.

Ospina-Tascón GA, Calderón-Tapia LE, García AF, et al. Effect of High-Flow Oxygen Therapy vs Conventional Oxygen Therapy on Invasive Mechanical Ventilation and Clinical Recovery in Patients With Severe COVID-19: A Randomized Clinical Trial [published correction appears in JAMA. 2022 Mar 15;327(11):1093]. JAMA. 2021;326(21):2161-2171. doi:10.1001/jama.2021.20714



IMPORTANCE

The effect of high-flow oxygen therapy vs conventional oxygen therapy has not been established in the setting of severe COVID-19.

OBJECTIVE

To determine the effect of high-flow oxygen therapy through a nasal cannula compared with conventional oxygen therapy on need for endotracheal intubation and clinical recovery in severe COVID-19.

DESIGN, SETTING, AND PARTICIPANTS

Randomized, open-label clinical trial conducted in emergency and intensive care units in 3 hospitals in Colombia. A total of 220 adults with respiratory distress and a ratio of partial pressure of arterial oxygen to fraction of inspired oxygen of less than 200 due to COVID-19 were randomized from August 2020 to January 2021, with last follow-up on February 10, 2021.

INTERVENTIONS

Patients were randomly assigned to receive high-flow oxygen through a nasal cannula (n = 109) or conventional oxygen therapy (n = 111).

MAIN OUTCOMES AND MEASURES

The co-primary outcomes were need for intubation and time to clinical recovery until day 28 as assessed by a 7-category ordinal scale (range, 1-7, with higher scores indicating a worse condition). Effects of treatments were calculated with a Cox proportional hazards model adjusted for hypoxemia severity, age, and comorbidities.

RESULTS

Among 220 randomized patients, 199 were included in the analysis (median age, 60 years; n = 65 women [32.7%]). Intubation occurred in 34 (34.3%) randomized to high-flow oxygen therapy and in 51 (51.0%) randomized to conventional oxygen therapy (hazard ratio, 0.62; 95% CI, 0.39-0.96; P = .03). The median time to clinical recovery within 28 days was 11 (IQR, 9-14) days in patients randomized to high-flow oxygen therapy vs 14 (IQR, 11-19) days in those randomized to conventional oxygen therapy (hazard ratio, 1.39; 95% CI, 1.00-1.92; P = .047). Suspected bacterial pneumonia occurred in 13 patients (13.1%) randomized to high-flow oxygen and in 17 (17.0%) of those randomized to conventional oxygen therapy, while bacteremia was detected in 7 (7.1%) vs 11 (11.0%), respectively.

CONCLUSIONS AND RELEVANCE

Among patients with severe COVID-19, use of high-flow oxygen through a nasal cannula significantly decreased need for mechanical ventilation support and time to clinical recovery compared with conventional low-flow oxygen therapy.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04609462.