Is overuse of high-flow nasal cannula therapy to blame?

From 2010-2019, the proportion of children admitted to the intensive care unit (ICU) for bronchiolitis doubled, an increase that was accompanied by a seven-fold increase in the use of non-invasive ventilation (NIV). Despite these increases, however, the rates of invasive mechanical ventilation did not change during the same period, researchers found.

Bronchiolitis is the most common lower respiratory illness in young kids, making up nearly 20% of U.S. hospitalizations in children less than 2 years of age. However, as interest in NIV—and particularly high-flow nasal cannula (HFNC) therapy—has grown in recent years, care patterns for pediatric bronchiolitis seem to be shifting, with drops in hospitalization rates and simultaneous increases in ICU admission. And, as Jonathan H. Pelletier, MD, of the Department of Pediatric Critical Care Medicine at the UPMC Children’s Hospital of Pittsburgh, Pennsylvania, and colleagues explained in Pediatrics, this shift was accompanied by increased inflation-adjusted costs of bronchiolitis hospitalization, from $449 million in 2003 to $734 million in 2016.

For their analysis, Pelletier and colleagues set out to characterize trends in use of invasive mechanical ventilation (IMV) and NIV, proportion of ICU patients admitted for bronchiolitis, and hospitalization costs for kids with bronchiolitis from 2010-2019 using the Pediatric Health Information Systems (PHIS) database.

“The present analysis of >200,000 admissions for bronchiolitis over 10 years demonstrates that the ICU admission proportion for bronchiolitis has doubled…,” Pelletier and colleagues reported. “This change outpaced overall ICU admission growth for children <2, which concomitantly rose only 33% over the study period…Understanding the reasons for increasing ICU admission proportion in this population is clinically important. Patients with bronchiolitis admitted to the ICU have a 10% to 18% incidence of new neurologic and functional morbidities, which affect their long-term quality of life. Thus, the developmental impacts of shifting patients from ward to ICU settings are unclear, and research efforts should be undertaken to predict and prevent hospital-acquired morbidities as this population grows.”

The study authors acknowledged that it is possible patients with bronchiolitis have become more ill over time in a way that was not captured in their database analysis—however, they noted that “if patients with bronchiolitis are becoming more ill over time, it would have to be occurring in a near-linear fashion to explain the trends seen in the current study, without regard for annual variability in pathogen virulence. This seems biologically implausible given previously published epidemiological data.”

Instead, Pelletier and colleagues posited that a substantial portion of the increase in ICU usage might stem from widespread adoption of HFNC oxygen therapy, a theory that Brian Alverson, MD, of Brown University in Providence, Rhode Island, and Shawn Ralston, MD, of Johns Hopkins University, Maryland, lent credence to in a commentary accompanying the study.

Part of the problem, Alverson and Ralston explained, is that coding for HFNC is inconsistent. For example, the therapy might be partially responsible for the seven-fold increase in NIV, a category that can encompass a wide variety of technologies. Some settings code HFNC as NIV, while others do not. And, they added, during the study period, many hospitals included in the PHIS database did not allow use of HFNC outside of an ICU setting. Unfortunately, the inconsistent coding for HFNC also makes it impossible to definitively prove this hypothesis via the PHIS database.

What’s more, the commentary authors pointed out that while HFNC use for bronchiolitis has exploded in the past decade, there is “no clear evidence HFNC is improving meaningful outcomes in bronchiolitis.”

For their retrospective, cross-sectional study, Pelletier and colleagues pulled data from PHIS on all patients age <2 years admitted for bronchiolitis and discharged from Jan. 1, 2010 through Dec. 31, 2019. The primary study outcomes were proportions of annual ICU admissions, IMV use, NIV use, and treatment-associated costs.

Pelletier and colleagues found that, of 203,859 total admissions for bronchiolitis across the decade, 39,442 (19.3%) were admitted to an ICU, 6,751 (3.3%) received IMV, and 9,983 (4.9%) received NIV.

“ICU admissions for bronchiolitis doubled from 11.7% in 2010 to 24.5% in 2019 (P<0.001 for trend), whereas ICU admissions for all children in Pediatric Health Information Systems <2 years of age increased from 16.0% to 21.1% during the same period (P<0.001 for trend),” they found. “Use of NIV increased seven-fold from 1.2% in 2010 to 9.5% in 2019 (P<0.001 for trend). Use of IMV did not significantly change (3.3% in 2010 to 2.8% in 2019, P=0.414 for trend). In mixed-effects multivariable logistic regression, discharge year was a significant predictor of NIV (odds ratio: 1.24; 95% confidence interval [CI]: 1.23–1.24) and ICU admission (odds ratio: 1.09; 95% CI: 1.09–1.09) but not IMV (odds ratio: 1.00; 95% CI: 1.00–1.00).”

The fact that increased rates of NIV use did not cause a corresponding decrease in IMV use is a particularly interesting finding, the study authors pointed out, suggesting that NIV—and particularly HFNC—”does not rescue patients destined for IMV.”

The study authors also found that, while hospital length of stay did not change significantly from 2010-2019, median (interquartile range) ICU length of stay decreased from 3 (2-6) days in 2010 to 2 (1-4) days in 2019.

In their commentary, Alverson and Ralston suggested that physicians may feel it necessary to transfer this patient population to the ICU for HFNC due to the increasing availability of the treatment and a sense of risk in delaying transfer, despite the lack of proof that the therapy improves outcomes—and, they added, this decision incurs substantial costs.

“Faced with these data, the implications are clear,” they wrote. “We need urgently to determine which infants truly benefit from the therapy so that we can reduce its use in the large population who incur only cost without benefit.”

They suggested creating criteria for initiation of HFNC, as well as weighing transfer to the ICU based on parental or physician anxiety against the increase in costs and risk associated with the transfer.

“Evidence is revealing we may be putting infants with bronchiolitis into ICUs without clear necessity, and this fact should prompt researchers to study and to address the problem,” they wrote.

Study limitations included lack of a nationally representative cohort, a lack of granular data regarding illness severity, and the variable coding practices for use of HFNC therapy.

  1. From 2010-2019, the proportion of children admitted to the intensive care unit (ICU) for bronchiolitis doubled and the use of non-invasive ventillation (NIV) increased seven-fold, but rates of invasive mechanical ventillation (IMV) did not change.

  2. The study authors suggested that a dramatic increase in use of high-flow nasal cannula (HFNC) might be responsible for the increase in ICU usage for bronchiolitis, but inconsistent coding for use of HFNC prevented them from assessing this hypothesis.

John McKenna, Associate Editor, BreakingMED™

The study and commentary authors had no relevant relationships to disclose.

Cat ID: 138

Topic ID: 85,138,728,791,570,730,138,192,195,925