Non Invasive Positive Pressure Ventilation in Status Asthmaticus

Asthma is a common, chronic and complex disorder of the airways, with symptoms that are variable and recurring. It is characterized by bronchial hyper-responsiveness to various stimuli, airflow obstruction that is often reversible, and underlying inflammation. Conventional therapy for status asthmaticus is directed at relieving broncho-constriction, decreasing airway inflammation and clearing airway mucus. However, in some patients, maximal standard therapies are inadequate and can lead to prolonged hospitalization. Intubation and mechanical ventilation in patients with asthma is associated with significant risks. NPPV has several advantages over invasive intubation and mechanical ventilation. It leaves the upper airway intact, and avoids the risks associated with endotracheal intubation including upper airway trauma, laryngeal swelling, postextubation vocal cord dysfunction, and nosocomial infections.

This study will be a prospective, open-labeled, randomized clinical trial comparing the use of NPPV plus standard of care versus standard of care alone in children admitted for status asthmaticus. A simple random numbers table will be used to assign subjects to either the NPPV plus standard of care group or standard of care alone group. In the first hour, all patients in both groups will receive a 2mg/kg dose of systemic steroid, continuous albuterol at 0.5mg/kg/hr (max of 15mg/hr) with 3 doses of 0.25-0.5 mg nebulized ipratropium bromide, and supplemental oxygen keep saturation >92%. Patients on both therapeutic arms will continue to receive 2mg/kg dose of systemic steroid per day, continuous albuterol at 0.5mg/kg/hr (max of 15mg/hr) and supplemental oxygen to keep saturation >92%.

Patients randomized to the NPPV plus standard of care group will be fitted with a nasal or face mask and placed on the Respironics V60 bilevel positive airway pressure (BiPAP) Ventilator 33. Masks with gel seals at different pressure points will be used to prevent skin breakdown. To optimize patient cooperation, the mask will initially be applied manually to the patient's face. After a short adaptation period for the patient to feel comfortable, the mask will be firmly applied with head straps to minimize air leak without causing skin injury. Pressures will initially be low for comfort and acceptance while being placed on the machine.

Patients randomized to the standard of care group will be placed on a similar continuous nebulizer attached to a similar oxygen blender as the ones used with the V60 unit set-up, using the same liter flow (11 liters per minute). An aerosol mask will be placed on the patient to aid in the delivery of the medication. The oxygen will be analyzed at the site of this mask with the initial set-up and any time the oxygen is decreased or increased.

Data will be collected at baseline as soon as the patient is enrolled in the study. It will include: demographic variables, medical record number, age, race, gender; history and physical findings, other medical conditions, vital signs, oxygen saturation at baseline, CAS, peak flow in children >6 years of age, asthma severity prior to admission, NPPV settings, length of stay in the PICU, side effect profiles (tremor, tachycardia, agitation, nausea, nasal bridge pain, skin irritation/ulceration, gastric distension, dry eyes/mucosal dryness, sinus/ear pain, aspiration pneumonia, hypotension and pneumothorax).

Each child's participation in the study will end when the child is transferred from the PICU.