Bronchiolitis: what's next?

Infants with severe respiratory syncytial virus needed less ventilator time with nasal continuous airways pressure then invasive mechanical ventilation

AIM

Nasal continuous positive airway pressure (NCPAP) has been proposed as an early first-line support for infants with severe respiratory syncytial virus (RSV) infection. We hypothesised that infants <6 months with severe RSV would require shorter ventilator support on NCPAP than invasive mechanical ventilation (IMV).

METHODS

Retrospective cohort analysis of infants admitted to two paediatric intensive care units, one primarily using NCPAP and one exclusively using IMV, between January 2008 and February 2010.

RESULTS

We studied 133 (NCPAP n = 89, IMV n = 46) consecutively admitted infants. On admission, disease severity [i.e. Paediatric RISk of Mortality (PRISM) II score (NCPAP 5.1 ± 2.8 vs. IMV 12.2 ± 6.0, p < 0.001) and SpO2 /Fi O2 ratio (NCPAP 309 ± 81 vs. IMV 135 ± 98, p < 0.001)] was higher in the IMV group. NCPAP remained independently associated with shorter ventilatory support (hazard ratio 2.3, 95% CI 1.1-4.7, p = 0.022) after adjusting for PRISM II score, PCO2 , SpO2 /Fi O2 ratio, bronchopulmonary dysplasia and occurrence of clinically suspected secondary bacterial pneumonia.

CONCLUSION

Nasal continuous positive airway pressure was independently associated with a shorter duration of ventilatory support. Differences in baseline disease severity mandate a randomised trial before the routine use of NCPAP can be recommended.

WITHDRAWN. Surfactant therapy for bronchiolitis in critically ill infants

BACKGROUND

Viral bronchiolitis is a common cause of respiratory failure in infants and children, and accounts for a significant portion of intensive care unit (ICU) admissions during seasonal epidemics. Currently there is no evidence to support the use of anything but supportive care for this disease. Surfactant is a potentially promising therapy; alterations in its composition have been described in bronchiolitis, and it may play a role in the host immunity for this disease.

OBJECTIVES

To assess the efficacy of exogenous surfactant for the treatment of bronchiolitis in mechanically ventilated infants and children.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2006, issue 1) which contains the Acute Respiratory Infections Group's Specialized Register; MEDLINE (1966 to Week 1, February 2006); and EMBASE (1990 to September 2005).

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing surfactant with placebo or surfactant with no surfactant in mechanically ventilated infants and children with viral bronchiolitis.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and assessed trial quality. Unpublished data were requested from trial authors when necessary.

MAIN RESULTS

Three trials containing a total of 79 patients met the inclusion criteria. No mortality or adverse effects associated with surfactant administration were reported in any of these trials. In the three trials, use of surfactant was associated with a decrease in duration of mechanical ventilation by 2.6 days (95% confidence interval (CI) -5.34 to 0.18 days; P value 0.07) and a decrease in ICU length of stay by 3.3 days (95% CI -6.38 to -0.23 days; P value 0.04). In two studies with 59 patients, in which duration of mechanical ventilation in the control groups was more comparable, surfactant was associated with a decrease in ventilator days by 1.21 days (95% CI 0.75 to 1.67 days) and a decrease in ICU stay by 1.81 days (95% CI 1.19 days to 2.42 days). Individually the studies reported some short term benefit of surfactant on pulmonary mechanics and gas exchange.

AUTHORS' CONCLUSIONS

Available data on surfactant were not sufficient to provide reliable estimates of its effects in mechanically ventilated infants and children with bronchiolitis. Future studies should be adequately powered and will need to address unresolved questions regarding which surfactant preparation may be best suited for the treatment of bronchiolitis, the appropriate dose and administration interval, and how the choice of ventilator strategy may modify its effects.

Surfactant therapy for bronchiolitis in critically ill infants

BACKGROUND

Viral bronchiolitis is a common cause of respiratory failure in infants and children, and accounts for a significant portion of intensive care unit (ICU) admissions during seasonal epidemics. Currently there is no evidence to support the use of anything but supportive care for this disease. Surfactant is a potentially promising therapy; alterations in its composition have been described in bronchiolitis, and it may play a role in the host immunity for this disease.

OBJECTIVES

The objective of this review was to assess the efficacy of exogenous surfactant for the treatment of bronchiolitis in mechanically ventilated infants and children.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 1, 2006); MEDLINE (1966 to Week 1, February 2006); and EMBASE (1990 to September 2005). We reviewed reference lists of relevant articles and contacted experts in the field.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing surfactant with placebo or surfactant with no surfactant in mechanically ventilated infants and children with viral bronchiolitis.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and assessed trial quality. Unpublished data were requested from trial authors when necessary.

MAIN RESULTS

Three trials containing a total of 79 patients met the inclusion criteria. No mortality or adverse effects associated with surfactant administration were reported in any of these trials. In the three trials, use of surfactant was associated with a decrease in duration of mechanical ventilation by 2.6 days (95% confidence interval (CI) -5.34 to 0.18 days; P value 0.07) and a decrease in ICU length of stay by 3.3 days (95% CI -6.38 to -0.23 days; P value 0.04). In two studies with 59 patients, in which duration of mechanical ventilation in the control groups was more comparable, surfactant was associated with a decrease in ventilator days by 1.21 days (95% CI 0.75 to 1.67 days) and a decrease in ICU stay by 1.81 days (95% CI 1.19 days to 2.42 days). Individually the studies reported some short term benefit of surfactant on pulmonary mechanics and gas exchange.

AUTHORS' CONCLUSIONS

Available data on surfactant were not sufficient to provide reliable estimates of its effects in mechanically ventilated infants and children with bronchiolitis. Future studies should be adequately powered and will need to address unresolved questions regarding which surfactant preparation may be best suited for the treatment of bronchiolitis, the appropriate dose and administration interval, and how the choice of ventilator strategy may modify its effects.

Bench-to-bedside review: Paediatric viral lower respiratory tract disease necessitating mechanical ventilation--should we use exogenous surfactant?

Treatment of infants with viral lower respiratory tract disease (LRTD) necessitating mechanical ventilation is mainly symptomatic. The therapeutic use of surfactant seems rational because significantly lower levels of surfactant phospholipids and proteins, and impaired capacity to reduce surface tension were observed among infants and young children with viral LRTD. This article reviews the role of pulmonary surfactant in the pathogenesis of paediatric viral LRTD. Three randomized trials demonstrated improved oxygenation and reduced duration of mechanical ventilation and paediatric intensive care unit stay in young children with viral LRTD after administration of exogenous surfactant. This suggest that exogenous surfactant is the first beneficial treatment for ventilated infants with viral LRTD. Additionally, in vitro and animal studies demonstrated that surfactant associated proteins SP-A and SP-D bind to respiratory viruses, play a role in eliminating these viruses and induce an inflammatory response. Although these immunomodulating effects are promising, the available data are inconclusive and the findings are unconfirmed in humans. In summary, exogenous surfactant in ventilated infants with viral LRTD could be a useful therapeutic approach. Its beneficial role in improving oxygenation has already been established in clinical trials, whereas the immunomodulating effects are promising but remain to be elucidated.