The Science Journal of the American Association for Respiratory Care

2005 OPEN FORUM Abstracts

HELIOX (He-O2) Use in Noninvasive Ventilation for Acute Exacerbation of ASTHMA.



Kevin Jacques RRT, Jerry Zimmerman MD, John Salyer RRT. Pediatric Intensive Care Unit and Respiratory Care Department. Children's Hospital and Regional Medical Center, University of Washington, Seattle WA.

Introduction:
Recent advances in technology available on the Viasys Avea ventilator simplify the use of He-O2 gas mixtures during positive pressure ventilator. This ventilator also can be used for non-invasive positive pressure ventilation (NIPPV). We report the use of He-O2 in combination with NIPPV in a pediatric application.

Case Report: A 13 year old female asthmatic was transported by paramedics to our emergency room where albuterol sulphate b2-agonist therapy per continuous nebulization was escalated to 30 mg/hr. Oral decadron was given and the patient was admitted to our general medical unit and treated according to our asthma protocol. ABG's were within normal limits. In spite of ipratropium bromide, continued high-dose continuous albuterol therapy, and IV methylprednisolone, within 24 hrs the patient required transfer to the PICU. Intubation appeared eminent. NIPPV with He-O2 was ordered. Having never used our newly acquired ventilators in such a manner, it took some time to assemble the necessary equipment. Meanwhile the patient was placed on an older bi-level positive pressure generator, with only slight improvement. Subsequently the patient was placed on the AVEA, non-invasively via full face mask: Mode = pressure support (PS), FIO2 = 0.30, FIHe = 0.70, PS = 8 cmH20, CPAP = 8 cm H20, (bi-level ventilation nomenclature: IPAP = 16 cmH20, EPAP = 8 cmH20). IV terbutaline was started and the IV methylprednisolone dose increased. Within moments of being placed on the Avea, observed work of breathing significantly diminished. She became more oriented and breath sounds also improved. Within 12 hours, NIPPV was discontinued, and continuous albuterol nebulization with He-O2 was re-started, this time using He-O2, FIO2 = 0.50, FIHE = 0.50. Later the same day, she was changed to intermittent metered dose inhaler albuterol therapy. The following morning, she was transferred out of the PICU and discharged on day 6.

Discussion: Avoiding intubation in pediatric patients with asthma is a well established clinical goal (Pediatr Crit Care Med 2004; 5(4):337-342). The Avea is the only ventilator that has built-in, FDA approved capacity to deliver He-O2 gas mixtures, and the ventilator has excellent non-invasive ventilation capabilities. This combination most probably allowed this patient to avoid intubation. In our experience, when used with He-O2, other bi-level devices perform poorly at sensing transition from expiration to inspiration. The low density of He-O2 makes it more difficult to ensure a mask seal. He-O2 consumption was high, requiring that H-cylinders be changed every two hours. However, the amount of He-O2 used was still less costly than endotracheal intubation and mechanical ventilation would have been, and much less risky to the patient. Design of the ventilator requires using masks that do not have the exhalation valve that other NIPPV masks have. Thus, if these masks for the Avea are inadvertently used with some other bi-level devices, there would be no path for exhalation, and potentially injurious to patients. To help prevent such an error, we are opening each of the masks for the Avea and manually labeling each of them for use with the Avea only.
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