Delayed intubation linked to poor survival among mechanically ventilated COVID-19 patients

Key takeaways:

• Patients with delayed vs. early intubation had worse hospital mortality, ICU mortality and death within 90 days.
• Delayed intubation linked to longer invasive mechanical ventilation and ICU stay.

Intubation after 24 hours in the ICU for patients with COVID-19 receiving mechanical ventilation resulted in poorer mortality outcomes than early intubation, according to study results published in European Respiratory Journal.

“In this large cohort study focusing on the effects of intubation timing in patients with COVID-19, we identified a higher risk of hospital mortality in those individuals with delayed intubation (> 24 hours of ICU admission) compared with those intubated within 24 hours of ICU admission,” Jordi Riera, MD, PhD, of the critical care department at University Hospital Vall d’Hebron, and colleagues wrote. “Likewise, we observed an increase in both ICU and 90-day mortality, ICU length of stay and mechanical ventilation duration in those patients intubated after the first 24 hours of ICU admission.”

In a secondary analysis of a multicenter, observational, prospective cohort study, Riera and colleagues analyzed 2,725 patients (median age, 64 years; 71.2% men) hospitalized with COVID-19-related respiratory failure and receiving invasive mechanical ventilation between Feb. 29, 2020, and Aug. 31, 2021, from 58 ICUs in Spain to determine the link between timing of intubation and in-hospital morality.

Additional assessments were conducted to evaluate intubation timing over the first four waves of the pandemic and how prior noninvasive respiratory support in combination with intubation timing impacted mortality.

Researchers propensity score matched patients intubated early (≤ 24 hours since ICU admission) and patients intubated after 24 hours from being admitted to the ICU to balance baseline characteristics of the two cohorts.

Of the total cohort, 1,694 patients underwent early intubation, and 1,031 underwent delayed intubation. Researchers observed that 37.6% of patients died in the hospital, and this outcome did not differ based on early or delayed intubation in unmatched analysis.

In the matched population of 614 patients (early intubation, n = 307; delayed intubation, n = 307), researchers found that those with delayed intubation experienced worse outcomes than those with early intubation, including greater hospital mortality (37.1% vs. 27.3%; P = .01), ICU mortality (36.1% vs. 25.7%; P = .007), death within 90 days (40.2% vs. 30.9%; P = .02), longer invasive mechanical ventilation (18 days vs. 13 days; P = .01) and ICU stay (27 days vs. 17 days; P < .001).

The risk for in-hospital mortality decreased with early intubation (OR = 0.63; 95% CI, 0.45-0.89) in logistic regression analyses when compared with delayed intubation, according to researchers.

When classifying early intubation within 48 hours of ICU admission, comparable results were found in sensitivity analyses, with a higher percentage of in-hospital death reported in patients who received delayed intubation (43.27% vs. 27.07%; P < .001).

In terms of early intubation prevalence across the four waves of the pandemic, researchers observed the highest use rate in the first wave (72%) and lower, similar rates in the second (49%), third (46%) and fourth (45%) waves.

Within the first wave, those who received delayed intubation experienced less death compared with those who received early intubation (hospital mortality, 34.4% vs. 40.2%; 90-day mortality, 35% vs. 42.5%) but researchers noted that this was because of older patients in the early intubation cohort and because the time period from symptom onset to intubation was not shorter than the recorded time for delayed intubation patients.

Early intubation in the second wave was linked to a significant decline in mortality, and this was also true in the third and fourth waves but was not statistically significant, according to researchers.

A subgroup analysis evaluating how high-flow nasal cannula (HFNC) and noninvasive ventilation (NIV) influenced in-hospital mortality included a matched population of 294 patients with HFNC and 214 patients with NIV.

Compared with early intubation in patients treated with HFNC, researchers found that delayed intubation in those with HFNC was linked to a greater risk for mortality (34.6% vs. 21.7%; P = .01).

No significant mortality difference was found between early and delayed intubation in patients receiving NIV (32.7% vs. 39.2%), according to researchers.

Sensitivity analysis that classified early intubation as within 48 hours of ICU admission further showed that delayed intubation was linked to more mortality than early intubation in HFNC (37.3% vs. 19.1%; P = .003), as well as in NIV (46.6% vs. 30.5%; P = .01).

“In patients intubated after 24 hours of ICU admission, we found worse respiratory mechanics compared with those intubated earlier (higher driving and positive end-inspiratory pressures with lower tidal volumes and similar positive end-expiratory pressures),” Riera and colleagues wrote. “This finding is consistent with prior literature, and may suggest further lung damage as a result of longer exposure to uncontrolled and spontaneous ventilation.”