Nebulized 3% hypertonic saline solution and chest physical therapy in ambulatory infant with viral bronchiolitis: a 2*2 factorial Randomized Controlled Trial
Acute Viral Bronchiolitis (AVB) is a leading cause of lower respiratory tract infection and is associated with substantial morbidity and mortality. Such pathogen leaves few therapeutic options with mainly symptomatology management and supportive care. Research into the variation in treatment and outcomes for bronchiolitis across different settings has led to evidence-based clinical practice guidelines. Several large, recent trials in emergency and hospital settings have revealed a lack of efficacy for routine use of either chest physical therapy (CPT) or hypertonic saline solution nebulization (HSS) for infants with the most severe form. Howevere, only 8% of the annual 450 000 children affected in France are hospitalized. Most children with bronchiolitis have actually a self-limiting mild disease and can be safely managed at home with careful attention to feeding and respiratory status. Nonetheless it puts a heavy burden on ambulatory care and children’s homecare. Similarly AVB puts an annual heavy economic burden on individual and health organization budgets.
Predominant pathological features in AVB are airway edema and mucus plugging. In situ experimentations have shown that hypertonic saline decreases airway edema, improves mucus rheologic properties and mucociliary clearance, and thus decreases airway obstruction. Last Cochrane systematic review considers SSH an effective and safe treatment for infants with mild to moderate AVB. Moreover, the recent AAP guideline recommends its use for inpatients. None the less several parameters may directly affect the efficacy of this treatment: the target population (age, severity), the diagnostic definition, the materiel use (compressor and nebulizer), the concentration and time of treatment, the overall duration of treatment, the outcome of reference. Rarely documented, these features need a closer attention for issuing accurate recommendation and may account for apparently opposite trials conclusions.
In a same way conventional CPT (postural drainage and percussion) and increased-exhalation technique used in most studies have been historically extrapolated from the adult or adolescent to the infant respiratory system. But the latter has a much different pulmonary tissue and ventilation mechanics that leads infant to tolerate respiratory loads poorly. Thus they are more prone to fatigue because of the immature pattern of their muscle fibers. It leads guidelines to dismiss CPT efficacy for AVB as a whole. Other physical techniques are currently used, by the respiratory therapist to enhance expectoration and restore normal breathing pattern to infants. The CPT treatment is crafted differently in each situation which made a single intervention design too blunt for uncovering efficacy. Ambulatory care provides a wide array of situation for the same pathology that cannot be infer from hospital investigation results only. Although less severe in most of its presentation, private health professionals have access to less technical and human resources in a longer time delay to respond to acute AVB. It concerns a great portion of infant population which has little coping leeway (especially pulmonary) making ongoing surveillance a critical task.
Finally we stand where a great array of not recommended treatments are prescribed with undermined consequences for both patient and society in terms of health and financial outcomes.
Despite the controversies, there are no randomized controlled trials that have yet provided sound scientific and technical evidence. Moreover Cochrane review and international guidelines call for considering a large RCT. Clarifying the organization of the health care pathway would rationalize treatment protocol, improve infant health and save money.
To assess the efficacy of (1) nebulization of 3% hypertonic saline solution and (2) chest physical therapy, in adjunction to rhino-pharyngeal clearance, at reducing the duration of symptoms (or, equivalently, at increasing the proportion of patient free of symptoms at day 5 +/- 1) in infant with acute moderate bronchiolitis