HFNC More Comfortable for Posthypercapnic Patients With COPD

Jeff Craven

August 21, 2020

Following invasive ventilation for severe hypercapnic respiratory failure, patients with chronic obstructive pulmonary disease had similar levels of treatment failure if they received high-flow nasal cannula oxygen therapy or noninvasive ventilation, recent research in Critical Care has suggested.

However, for patients with COPD weaned off invasive ventilation, high-flow nasal cannula (HFNC) oxygen therapy was "more comfortable and better tolerated," compared with noninvasive ventilation (NIV). In addition, "airway care interventions and the incidence of nasofacial skin breakdown associated with HFNC were significantly lower than in NIV," according to Dingyu Tan of the Clinical Medical College of Yangzhou (China) University, Northern Jiangsu People's Hospital, and colleagues. "HFNC appears to be an effective means of respiratory support for COPD patients extubated after severe hypercapnic respiratory failure," they said.

The investigators screened patients with COPD and hypercapnic respiratory failure for enrollment, including those who met Global Initiative for Obstructive Lung Disease (GOLD) criteria, were 85 years old or younger and caring for themselves, had bronchopulmonary infection–induced respiratory failure, and had achieved pulmonary infection control criteria. Exclusion criteria were:

  • Patients under age 18 years.

  • Presence of oral or facial trauma.

  • Poor sputum excretion ability.

  • Hemodynamic instability that would contraindicate use of NIV.

  • Poor cough during PIC window.

  • Poor short-term prognosis.

  • Failure of the heart, brain, liver or kidney.

  • Patients who could not consent to treatment.

Patients were determined to have failed treatment if they returned to invasive mechanical ventilation or switched from one treatment to another (HFNC to NIV or NIV to HFNC). Investigators also performed an arterial blood gas analysis, recorded the number of duration of airway care interventions, and monitored vital signs at 1 hour, 24 hours, and 48 hours after extubation as secondary analyses.

Overall, 44 patients randomized to receive HFNC and 42 patients randomized for NIV were available for analysis. The investigators found 22.7% of patients in the HFNC group and 28.6% in the NIV group experienced treatment failure (risk difference, –5.8%; 95% confidence interval, −23.8 to 12.4%; P = .535), with patients in the HFNC group experiencing a significantly lower level of treatment intolerance, compared with patients in the NIV group (risk difference, ­–50.0%; 95% CI, −74.6 to −12.9%; P = .015).

There were no significant differences between either group regarding intubation (−0.65%; 95% CI, −16.01 to 14.46%), while rate of switching treatments was lower in the HFNC group but not significant (−5.2%; 95% CI, −19.82 to 9.05%).

Patients in both the HFNC and NIV groups had faster mean respiratory rates 1 hour after extubation (P < .050). After 24 hours, the NIV group had higher-than-baseline respiratory rates, compared with the HFNC group, which had returned to normal (20 vs. 24.5 breaths per minute; P < .050).

Both groups had returned to baseline by 48 hours after extubation. At 1 hour after extubation, patients in the HFNC group had lower PaO2/FiO2 (P < .050) and pH values (P < .050), and higher PaCO2 values (P less than .050), compared with baseline. There were no statistically significant differences in PaO2/FiO2, pH, and PaCO2 values in either group at 24 hours or 48 hours after extubation.

Daily airway care interventions were significantly higher on average in the NIV group, compared with the HFNC group (7 vs. 6; P = .0006), and the HFNC group also had significantly better comfort scores (7 vs. 5; P < .001) as measured by a modified visual analog scale, as well as incidence of nasal and facial skin breakdown (0 vs. 9.6%; P = .027), compared with the NIV group.

Results Difficult to Apply to North American Patients

David L. Bowton, MD, FCCP, a professor specializing in critical care at Wake Forest University, Winston-Salem, N.C., said in an interview the results of this trial may not be applicable for patients with infection-related respiratory failure and COPD in North America "due to the differences in common weaning practices between North America and China."

For example, the trial used the pulmonary infection control (PIC) window criteria for extubation, which requires a significant decrease in radiographic infiltrates, improvement in quality and quantity of sputum, normalizing of leukocyte count, a synchronized intermittent mandatory ventilation (SIMV) rate of 10-12 breaths per minute, and pressure support less than 10-12 cm/H2O (Int J Chron Obstruct Pulmon Dis. 2017;12:1255-67).

"The process used to achieve these measures is not standardized. In North America, daily awakening and screening for spontaneous breathing trials would be usual, but this was not reported in the current trial," he explained.

Differences in patient population also make the application of the results difficult, Dr. Bowton said. "Only 60% of the patients had spirometrically confirmed COPD and fewer than half were on at least dual inhaled therapy prior to hospitalization with only one-third taking beta agonists or anticholinergic agents," he noted. "The cause of respiratory failure was infectious, requiring an infiltrate on chest radiograph; thus, patients with hypercarbic respiratory failure without a new infiltrate were excluded from the study. On average, patients were hypercarbic, yet alkalemic at the time of extubation; the PaCO2 and pH at the time of intubation were not reported.

"This study suggests that in some patients with COPD and respiratory failure requiring invasive mechanical ventilation, HFO [high-flow oxygen] may be better tolerated and equally effective as NIPPV [noninvasive positive-pressure ventilation] at mitigating the need for reintubation following extubation. In this patient population where hypoxemia prior to extubation was not severe, the mechanisms by which HFO is beneficial remain speculative," he said.

This study was funded by the Rui E special fund for emergency medicine research and the Yangzhou Science and Technology Development Plan. The authors report no relevant conflicts of interest. Dr. Bowton reports no relevant conflicts of interest.

SOURCE: Tan D et al. Crit Care. 2020 Aug 6. doi: 10.1186/s13054-020-03214-9.

This article originally appeared on MDedge.com, part of the Medscape Professional Network.


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