Efficacy of Percussive Ventilation Therapy (MetaNeb ®) Compared With Mucolytic Agents for Atelectasis in the Mechanically Ventilated Pediatric Patient

Efficacy of Percussive Ventilation Therapy (MetaNeb ®) Compared With Mucolytic Agents for Atelectasis in the Mechanically Ventilated Pediatric Patient

Efficacy of Percussive Ventilation Therapy (MetaNeb ®) Compared With Mucolytic Agents for Atelectasis in the Mechanically Ventilated Pediatric Patient

The purpose of this study is to evaluate whether a therapy that uses a machine called a continuous high frequency oscillator (CHFO) is more successful at removing mucus than medications that thin out the mucus.

Both of these therapies (CHFO and medication) are currently used in the Pediatric Intensive Care Unit and Pediatric Cardiac Intensive Care Unit. This research study is being done because the investigator is trying to learn if the mechanical removal of mucus with CHFO will effectively re-inflate the collapsed area of lung. Specifically, the study team will determine if CHFO can improve lung inflation with the same or improved vital signs (heart rate, blood pressure, and breathing rate), and the same or improved ability to help the lungs move oxygen into the blood. One of the problems with the medication approach is that while it thins out the mucus, actual removal from the lung requires a strong cough which is difficult for infants and children to produce when they are sedated and on a ventilator (breathing machine). Thus, the aim of this research study is to test whether children with atelectasis on a ventilator are more likely to improve with mechanical removal of their mucus with the CHFO as compared with medications that thin out the mucus. CHFO and all the medications used in this study are part of the standard of care for atelectesis. However, there is no information on which combination works best and no one agrees that one approach is more effective than another. Usually patients are evaluated for 48 hours after starting treatment, before adding or making any changes.

Subjects randomized to receive therapy with the CHFO will receive a 20 minute treatment every 6 hours for 48 hours.

Subjects randomized to receive the medications will receive acetylcysteine and dornase alfa, two medications frequently used in the treatment of atelectasis. The medications will alternate every 6 hours for 48 hours.

An atelectasis score (AS), as published by Deakins, et al. 2002, was assigned to each radiograph as follows: 0 Complete resolution of collapse Partial collapse of 1 segment or lobe Partial collapse of ≥ 2 segments or lobes Complete collapse of 1 segment or lobe Complete collapse of ≥ 2 segments or lobes In the event of inter-rater disagreement, the scores were averaged. Improvement was defined as any decrease in AS ≥ 0.5. Worsening was defined as an increase in AS ≥ 0.5 or escalation of respiratory support modality (i.e. high frequency ventilation).

The deadspace-to-tidal volume (Vd/Vt) ratio is a parameter that is measured in mechanically ventilated patients as a way to assess the severity of gas exchange impairment and to assist in determining whether a patient is ready to be weaned from the ventilator. The change from baseline was measured at 48 hours, with a decreasing ratio indicating improvement.

Inclusion Criteria: Informed consent from parent or legal guardian. Age < 18 years and admitted to the PICU or PCICU. Conventionally ventilated. Mucolytics are being initiated by clinical team for treatment of atelectasis. Endotracheal tube ≥ 3.5 mm internal diameter. Exclusion Criteria: Receiving chronic mucolytic or continuous high frequency oscillation therapy. Clinically significant pleural effusion. Status post cardiothoracic surgery with open chest. Pneumothorax. Pulmonary hemorrhage. Escalating doses of vasoactive agents (i.e. dopamine or epinephrine).