Mechanical ventilation strategies for infants with bronchiolitis vary across centers

A new study identified between-center variations in practices and outcomes of invasive mechanical ventilation for infants with acute bronchiolitis.

“Bronchiolitis is the most common reason for being admitted to pediatric critical care units in the U.K.,” Rebecca B. Mitting, MD, pediatric intensive care unit consultant at St. Mary’s Hospital, London, said during a presentation at the virtual Society for Critical Care Medicine’s Critical Care Congress.

However, she said, management of bronchiolitis in ventilated children is not standardized in the U.K.

In the current study, “a large difference in duration of mechanical ventilation between centers with different management strategies [for] children with bronchiolitis was found,” Mitting said.

The researchers conducted a retrospective, multicenter, cohort study to assess differences in processes of care between three geographically similar pediatric ICUs in the U.K and evaluate whether there were differences in duration of mechanical ventilation for infants younger than 1 year with a diagnosis of acute viral bronchiolitis from 2013 to 2016.

Researchers collected data on corrected gestational age at pediatric ICU admission, gestational age at birth, weight, respiratory syncytial virus (RSV) status, bacterial coinfection on initial tracheal aspirate, initial oxygen saturation index, pediatric index of mortality (PIM-2) risk score and comorbidities.

The primary outcome was invasive mechanical ventilation duration. The secondary outcome was duration of pediatric ICU stay in hours.

The 462 infants (median corrected gestational age, 1 month) included were admitted to center A (n = 169), center B (n = 124) or center C (n = 169). Nearly 20% of all infants were born premature at less than 32 weeks. RSV, bacterial coinfection on tracheal aspirate and comorbidities were found in a proportion of infants in center A (60%, 21% and 17%, respectively), center B (61%, 10% and 19%, respectively) and center C (55%, 17% and 25%, respectively).

Median oxygen saturation index was 5 to 6.4. All centers had a PIM-2 risk score of less than 1%.

Center A had a larger proportion of infants who received opiate infusions (98%) and midazolam infusions (55%), but a lower proportion of infants who received nasal endotracheal tube (2.9%). At center C, 93% of infants received an alpha-2 agonist compared with 1.6% at center B and 0% at center A. At center A, cumulative fluid balance was highest, at 62 mL/kg at 48 hours compared with 23 mL/kg at center B and 18 mL/kg at center C.

Infants treated at center A had a longer duration of invasive mechanical ventilation (126 hours) and a longer overall pediatric ICU stay (166 hours) compared with center B (86 hours and 138 hours, respectively) and center C (93 hours and 122 hours, respectively).

An unsuccessful extubation attempt, receiving neuromuscular blockage, IV opiate infusion, midazolam infusion and having a positive fluid balance were associated with a longer duration of invasive mechanical ventilation in univariate analysis. Receiving alpha-2 agonists and having nasal endotracheal tube were associated with a reduced duration of invasive mechanical ventilation.

After adjusting for all confounders, there was a 44% (95% CI, 25-66; P < .001) increase in mean duration of invasive mechanical ventilation at center A compared with the other two centers.

In the multivariate model, comorbidity, bacterial coinfection at tracheal aspirate, increased oxygen saturation index and being born premature at less than 32 weeks were associated with increased invasive mechanical ventilation duration. The multivariate model also assessed the interaction effect between corrected gestational age and prematurity, showing that at 0 months, infants born at less than 32 weeks’ gestation had a 55% increase in invasive mechanical ventilation duration compared with those born at term. However, as the infant ages, this effect is reduced; by the time the infant s at the corrected gestational age of around 8 months, their length of invasive mechanical ventilation will be equivalent, Mitting said.

The researchers noted several limitations of the trial, including its retrospective design.

“The management strategies that we studied are center-specific, which are not possible to say whether they were associated with differences in duration of ventilation independent of the center in which the infant was cared for. It is also not possible from this data to identify which of the care factors that we studied had the most influence on outcome or, in fact, if other unidentified outcomes were more important,” Mitting said.

The data were published in Pediatric Critical Care Medicine.

Reference:

Mitting RB, et al. Pediatr Crit Care Med. 2021;doi:10.1097/PCC.0000000000002631.