A randomized clinical trial with blinding of person assigned for assessing and scoring the
patients. The participants will include children less than 2 yrs. age admitted to the
Pediatric Intensive Care Unit (PICU) with a diagnosis of acute bronchiolitis who will be
randomized into either the NAC group or the non-NAC (Control) group.
Patients with acute bronchiolitis who require to be started on high flow nasal cannula
support or any other noninvasive ventilator/BIPAP support are transferred/directly admitted
to PICU. There is no time limit between when patients are admitted and when patients must
sign consent or be randomized.
After a patient with acute bronchiolitis is identified, a member of the study team will
perform a chart review to assess eligibility as described by the inclusion/exclusion
criteria. If eligible, parent(s)/guardian(s) will be approached and Informed Consent will be
obtained. Using randomization software(www.randomizer.org) the enrolled patients will be
randomly assigned to either the NAC group or the non-NAC (Control) group.
The NAC will be ordered by the on call pharmacist and it will be administered by the on call
Respiratory therapists. Between the two groups only the NAC group will get nebulized 2 ml of
10% NAC solution every 12 hours during their stay in PICU.
The PICU uses HHFNC (humidified high flow nasal canula), Heliox and non-invasive ventilation
such as RAM canula, Neurally adjusted ventilatory assist (NAVA) and BIPAP. The PICU also
typically uses Dexmedetomidine infusion once the patient is on non invasive ventilation (NIV)
as a light sedation medication to avoid agitation and better ventilation patient synchrony.
The scoring tool used by Seattle children's Bronchiolitis pathway will be used. HHFNC
(humidified high flow nasal cannula) will be started for patients when scores are ≥2.
Depending on the clinical worsening the patient may require help with Heliox and escalation
to non-invasive ventilation.
There will be twice a day blind assessments completed by experienced PICU/Transport nurses
who were non-involved in patient care in PICU at that time. The pharmacist is going to use
randomization software to randomly assign patients to a group (i.e control vs treatment).
Also, the pharmacist will order code called as "Trial***" in the medical record (*** denotes
a number assigned) and depending on the randomization the patient may or may not get the
trial medication (Nebulized NAC). As such, all patients in the study will have a medical
record orders which look similar to help achieve blinding at this stage for the treating
physicians and independent evaluators.
All patients in the study will receive a type of respiratory support, such as High flow nasal
cannula, noninvasive ventilator/ BIPAP etc. and because the NAC neb can easily be given
through those circuits, no extra equipment will be required for patients who are in the
treatment (NAC) group. Given that there is no difference in equipment in both treatment and
control groups, the only way the double-blind is broken in this scenario is NAC's odor.
The odor of Neb NAC typically stays in the room during the treatment (2-3 minutes) and should
not last >30 minutes after every administration. NAC is a sulfur compound and hence smells
like "rotten eggs" so for precaution to maintain blindness, a respiratory therapist will
spray a commercial rotten egg smelling solution at approximately the same time as treatment
is administered for all patients in the study.
Because the NAC neb will be delivered through a closed respiratory circuit and also because
the respiratory therapists use filters for nebulization treatments, the chances of sticky
residues will be lower and hence difficult to figure out by examination.
The 12 hourly neb treatments will occur from 6:30-7:30am and pm respectively. This timing
works in favor for blinding because both attending physicians and the independent evaluators
are less likely to be present during this time. The assessment will involve scoring the
patients according to the bronchiolitis scoring data tool. These assessments will be
completed for the duration of the PICU stay. The on service PICU attendings will only be
involved in clinical management of patients and will be blinded from randomization. The
blinding will be broken if one of the on service physicians or PICU/Transport nurses
performing assessments are aware of the currently admitted patient randomization details.
Reasons subjects may be withdrawn from the study: patient gets transferred to another
facility due to family's requests, family wishes to withdraw in the middle of the study, or
to protect the welfare of the patient.