Please select the eligibility criteria that correspond to the clinical trial below.
Title: Observational, Cross-over Study of the Positive Distending Pressure Generated by Humidified High Flow Nasal Cannula as Compared to Nasal Continuous Positive Airway Pressure
Brief Summary: The specific aims of this study are to evaluate the amount of high flow nasal cannula (HFNC) gas flow required to generate an equivalent positive distending pressure as that provided by nasal continuous positive airway pressure (NCPAP) of 6 cm H2O, assess the relationships between positive distending pressure, gas flow, oxygen requirement, and patient weight, and lastly, develop an appropriate protocol to be used in the NICU for transitioning patients from NCPAP to an equivalent amount of HFNC.


Options:
A: Inclusion Criteria:

* Clinical diagnosis of bronchiolitis defined as the first viral episode of respiratory distress before 2 years of aging, presenting with rhinitis, tachypnea, cough, wheezing, prolonged expiratory time, crackles and use of accessory muscles, with or without fever, with or without infiltrate on the chest X ray
* bronchiolitis severity Wang modified score ≥ 10

Exclusion Criteria:

* recurrent wheezing
* heart disease
* chronic lung disease
* neuromuscular disease
* primary diagnosis was not bronchiolitis (pneumonia, pertussis)
* critically ill infants who had an immediate need of intubation
B: Inclusion Criteria:

Eligible patients will fall into one of two groups:

Group A (Step-up)

1. Age \>36 weeks corrected gestational age and \<16 years, AND
2. Deemed to require non-invasive respiratory support by the treating clinician for an acute illness, AND
3. Satisfies one or more of the following criteria:

   * Hypoxia (oxygen saturation \<92% in fraction of inspired oxygen (FiO2) \>0.40, or equivalent). FiO2 of 0.40 roughly equates to standard unhumidified nasal cannula oxygen delivered at 6 L/min or oxygen delivered via facemask without a rebreather bag at 6-10 L/min.
   * Acute respiratory acidosis (pH \<7.3 with a concomitant pCO2 \>6.5 kPa)
   * Moderate respiratory distress (use of accessory muscles, subcostal and intercostal recession, tachypnoea for age, grunting)

Group B (Step-down)

1. Age \>36 weeks corrected for gestation and \<16 years, AND
2. Deemed to require non-invasive respiratory support by the treating clinician after extubation, following a spell of invasive ventilation

   * Either immediately after extubation as a 'planned' procedure, irrespective of clinical condition ('planned') OR
   * Prompted by deterioration in clinical condition within 72 hours after extubation ('rescue'). Clinical parameters to assess the need for NRS in this situation will be similar to point 3 in Group A.

Exclusion Criteria:

1. Deemed by the treating clinician to require immediate intubation/invasive ventilation due to severe hypoxia, acidosis and/or respiratory distress, upper airway obstruction or recurrent apnoeas
2. Tracheostomy in place
3. Pre-existing air-leak syndrome (pneumothorax/pneumomediastinum)
4. Midfacial/craniofacial anomalies (unrepaired cleft palate, choanal atresia) or had recent craniofacial surgery
5. Agreed limitation of intensive care treatment plan in place ('not for intubation')
6. On domiciliary non-invasive ventilation prior to PICU admission
7. Managed on either HFNC and/or CPAP (or other form of non-invasive ventilation such as BiPAP) in the preceding 24 hours
8. Previously recruited to this study during the same PICU admission
9. Cannot be treated with HFNC

   * Unavailability of appropriate sized nasal prongs
   * Unavailability of HFNC device
10. Cannot be treated with CPAP

    * Unavailability of right size of face mask, prong or other patient interface
    * Unavailability of CPAP device
C: Inclusion Criteria:

* 1) receiving NCPAP ventilatory support at \> 72 hrs. of age and 2) requiring FiO2 21-50% on NCPAP.

Exclusion Criteria:

* FiO2 \>50%, presence of pneumothorax or pleural effusion, anatomical abnormalities of the airway, lungs, or esophagus, or cyanotic congenital heart defect.
D: Inclusion Criteria:

Children of either sex, aged 0-4 years, with severe/very severe pneumonia (per WHO guidelines) and hypoxaemia (SpO2 \< 90%) will be included in our study in the ARI Unit of the Longer Stay Ward (LSW), High Dependency Unit HDU, and ICU unit of Dhaka Hospital of ICDDR,B.

Exclusion Criteria:

Children with uncorrected cyanotic CHD, hypercapnoea (PCO2 \> 65 mm of Hg), status asthmaticus and upper-airway obstruction, and those for whom inform consent can't be secured from their parents/ care-givers. Children with features (any two of three criteria given below) of "treatment failure" on admission (before enrollment into the study) will also be excluded from the study. Arterial blood gas analysis will be performed to check the exclusion criteria

Answer: C