Breath-holding may predict adverse outcomes in COVID-19 patients

A higher prediction score in breath-holding is associated with nearly a fivefold increased likelihood of respiratory failure in COVID-19 patients, as well as with greater severity of pulmonary deficits seen in chest imaging, a study has shown.

“We validated a prediction model that captures deficits in breath-holding physiology and detects hospitalized patients who are at increased risk of later developing adverse COVID-19 outcomes,” the researchers said. “Breath-holding physiology may have utility for rapid identification of COVID-19 patients at elevated risk of respiratory failure particularly in circumstances where resources are limited.”

In this prospective validation study, 110 hospitalized COVID-19 patients from three recruitment centres performed breath-holds at admission to provide a prediction score based on mean desaturation (20-s breath-holds) and maximal breath-hold duration, along with baseline saturation, body mass index, and cardiovascular disease.

The researchers described odds ratios (ORs) for incident adverse outcomes (composite of bi-level ventilatory support, intensive care unit admission, and death) for patients with and without elevated scores (>0). They also examined the associations with chest X-ray and computed tomography (CT) and made further comparisons with the previously validated 4C-score.

An elevated breath-holding prediction score correlated with adverse COVID-19 outcomes (n=12; OR, 4.54, 95 percent confidence interval [CI], 1.17‒17.83; p=0.030; positive predictive value, 9/48; negative predictive value, 59/62). This association was attenuated when mean desaturation was removed from the model (OR, 3.30, 95 percent CI, 0.93‒11.72). [Respirology 2022;27:1073-1082]

Moreover, the prediction score showed a linear increase with Brixia score (β, 0.13, 95 percent CI, 0.02‒0.23; p=0.026; n=103) and CT-based quantification (β, 1.02, 95 percent CI, 0.39‒1.65; p=0.002; n=45). Mean desaturation correlated with both radiological assessments.

“Notably, mean desaturation … was a meaningful contributor to the prediction model (odds lowered from fivefold to threefold without this measurement),” the researchers said. “Our study further supports the notion that breath-hold induced desaturation can provide meaningful information on gas exchange deficits in COVID-19 beyond baseline saturation alone.”

Comparison with 4C-score

On the other hand, elevated 4C-scores showed a weak association with adverse outcomes (OR, 2.44, 95 percent CI, 0.62‒9.56).

The 4C-score covers parameters on patient demographics, comorbidity, physiology, and inflammation at hospital admission. It worked well in external validation, unlike other prognostic scores that only performed moderately because external validation populations were either small or diverse in case-mix and severity. [medRxiv 2020:2020.03.28.20045997]

“The 4C-score was associated with our prediction score but had weaker association with adverse outcome than our prediction score in our population. Explanations could be that the 4C-score mainly predicts in-hospital mortality risk, and our population sample was not large enough to produce a significant finding,” the researchers said.

“Regardless, our prediction score performed well in our external validation sample and outperformed the 4C-score by magnitude of risk. Further research is warranted to confirm these findings,” they added.