The Science Journal of the American Association for Respiratory Care

2006 OPEN FORUM Abstracts

HELIOX (HeO2) Use with a nasal cannula (NC) for Acute airway edema and post extubation stridor

 Christina Collin RRT-NPS, Robert DiBlasi RRT-NPS, John Salyer RRT-NPS, MBA, FAARC. Respiratory Care Department. Children's Hospital and Regional Medical Center , Seattle WA .

Introduction: Inhaled HeO2 has been used to reduce symptoms created by airflow obstruction in pediatric respiratory disease. The lower density of helium versus nitrogen allows for a reduction in work of breathing (WOB). This therapy is usually administered to spontaneously breathing patients via non-rebreathing mask, oxygen tent, or hood. However, these devices are sometimes not well tolerated by children. We report the use of HeO2 via NC in a patient with acute airway edema & subsequent stridor. Case Report: A 4 month old male with congenital left frontonasal encephalocele was admitted for a 9.5 hour surgical repair. He was intubated in the O.R. with a cuffed 3.5 ETT. After surgery the patient was in the PICU on a ventilator, where he remained intubated overnight for airway protection. On the second day after surgery, a dose of dexamethasone was given at 0600 in anticipation of extubation. Morphine and lorazepam drips were given for agitation and ventilator dysynchrony. At 0900, the lorazepam and morphine drips were decreased and the patient was extubated at 0930 and immediately developed severe respiratory distress including: supra-substernal and intercostal retractions, marked inspiratory stridor, nasal flaring, and severely diminished breath sounds. The patient could not be nasally suctioned due to post operative restrictions mandated by the surgeons. The lorazepam was discontinued and the morphine was decreased. At 0940, a racemic epinephrine nebulizer treatment was given via nebulizer. Diminished breath sounds and upper airway stridor persisted. The patient was placed on mask CPAP via manual resuscitator. Clinical staff began preparing for reintubation. Naloxone was given followed by another dose of dexamethasone. The patient became more alert. Another racemic epinephrine treatment was given. HeO2 was started via NC @ 2 L/m of a 70/30% mixture. Stridor and WOB improved slightly but the patient became agitated. The morphine drip was increased. Breath sounds improved and inspiratory stridor and WOB diminished significantly. Discontinuation of HeO2 was attempted but there was an immediate increase in WOB and stridor. HeO2 was changed to 1 L/m at a 25/75% at 1500. The patient was given a third dose of dexamethasone and was changed to 80/20 mixture and weaned completely by 1830.

Time  Line Comment pH PaCO2 PaO2
0930 Extubation severe respiratory  distress
0940 Mask CPAP 7.19 61 61
1000 HeO2 70/30 @ 2 L/m 7.25 42 112
1500 HeO2 75/25 @ 1 L/m 7.33 37 138
1630 HeO2 80/20 @ 1 L/m ¯          work of breathing ¯           stridor
1830 Room air

Discussion: Avoiding reintubation in pediatric patients with post-extubation airway edema can be a clinically challenging. HeO2 via NC appears to have helped this patient avoid reintubation until IV steroids were able to take effect.  However, racemic epinephrine was also given, and may have contributed to this patient's improvement. This apparent effectiveness of the administration of HeO2 through a nasal cannula may be due in part to the low inspiratory flow rates and obligatory nasal breathing patterns that are often observed in the pediatric population. Both of these factors would have contributed to a low rate of entrainment of ambient air and thus kept the inspired concentration of HeO2 as high as possible.

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