Cardiopulmonary parameters were measured and recorded at baseline, just before and at every minute during NC-AC, and at the end of the FB session. In infants who already had an arterial line, arterial blood gas (ABG) analyses were taken for study. Data was represented as mean ± SD. The results obtained from the baseline and different stages. The values were considered statistically significant only when p < 0.05.

Technique failure was defined as: any vital signs of hypoxia did not return to accepted levels(HR>100 beat/min, SpO2>90%, mean BP>50 mmHg)within 2 minutes of the experimental CPR technique. Then traditional CPR procedures involving bag-mask ventilation, endotracheal intubation, Ambu bag ventilation or even chest compressions were substituted.

Infants with body weight (BW) <5.0 kg and receiving nasal diagnostic or interventional FB were enrolled. Under NPO (0.5 L/kg/min), when infant's heart rate (HR) <80 beats/min or oxygen saturation (SpO2) <85% for more than 10 seconds, rescue NC-AC was initiated. It was performed by (1) increased NPO flow to 0.5-1.0 L/kg/min; (2) NC 1 second for inspiration; and (3) AC 1 second for expiration with simultaneously released nostrils. Repeat doing steps (2) and (3) at a rate of 30 cycles/min until HR, SpO2, and blood pressure (BP) returned to normal.

During and after this FB procedure, vital signs are continually monitoring. When the heart rate (HR) <80 beat/min (measured by continuouse wave and digit form of EKG monitor) and lasting >10 seconds. Immediately rescued with rhythmic NC-AC. If the heart rate did not reach to its acceptable level (>80 beat/min) within 2 minutes, then traditional CPR procedures involving bag-mask ventilation, ET intubation, Ambu bag ventilation or even chest compressions were substituted.

During FB procedure, vital signs are continually monitoring. When the oxygen saturation <85% (or more than 10% below the original baseline in already cyanotic infant)by pulse oximeter and lasting >10 seconds. Immediately rescued with rhythmic NC-AC. If the oxygen saturation did not reach to its acceptable level (>85%) within 2 minutes, then traditional CPR procedures involving bag-mask ventilation, ET intubation, Ambu bag ventilation or even chest compressions were substituted.