The Science Journal of the American Association for Respiratory Care

2003 OPEN FORUM Abstracts

Clinical Effects of Maintaining Mean Airway Pressure during IPV on Mechanically Ventilated Pediatric Patients in the PICU

Kathleen Deakins RRT-NPS, Michael Tracy RRT-NPS, Timothy Myers RRT-NPS. Rainbow Babies & Children's Hospital. Cleveland, OH.

Introduction: Intrapulmonary Percussive Ventilation (IPV) is a therapeutic modality designed to mobilize and facilitate secretion removal, re-expand areas of collapse, increase deposition of aerosolized particles and improve gas exchange. During IPV, at mechanical end-expiratory phase, dynamic functional residual capacity is maintained by a time-limited expiratory phase that allows the peak pressures to return to baseline as opposed to maintaining elevated baseline pressures at end-expiration with PEEP. In our institution, patients receiving mechanically ventilation and IPV are removed from the ventilator, have the IPV circuit attached to the endotracheal tube, and are percussed by depressing the remote switch on the IPV circuit. We observed episodes of acute oxygen desaturation in patients removed from the ventilator for IPV treatments when mean airway pressures (Paw) are >12 cm H20. During a bench evaluation (Resp Care 2001; 46(10):1124), the addition of an adjustable PEEP valve to the IPV circuit facilitated more consistent PEEP compared to PEEP on the ventilator with an IPV circuit placed in-line with the ventilator circuit. The purpose of this evaluation was to assess the clinical effects of adding a disposable PEEP valve during IPV treatments for mechanically ventilated patients requiring high Paw. 

Methodology: 18 patients residing in the PICU, aged 2 weeks to 15 years, mechanically ventilated with PEEP ranging +5 to +12 cm H20 and Paw ranging from 12 to 19 cm H20, were ordered to receive IPV treatments as a form of airway clearance or lung expansion therapy during their ICU stay. Patients were removed from the ventilator for their IPV treatments per department protocol. All 18 patients exhibited decreased oxygen saturation (Sp02) from baseline (>91%) to a 70-80% range with initiation of IPV treatments. Following oxygen desaturation, treatments were stopped so an adjustable PEEP valve could be added to the exhaust port of the IPV circuit. Treatments were resumed with the addition of PEEP of +5 or +10 cm H20 set on an adjustable PEEP valve. A pressure change from inspiration to expiration (DP) of 10 to 20 cm H20 was maintained on all patients. Vital signs including heart rate, oxygen saturation, systolic and diastolic blood pressure were monitored before and after IPV treatments given with PEEP. The differences in mean values in pre and post vital signs were compared using the student's unpaired t-test.

: There were no significant changes in vital signs to suggest cardiovascular compromise when adding PEEP to the IPV circuit. There was a statistically significant difference (increase) in pre and post oxygen saturation following the addition of PEEP to the IPV circuit (p < 0.028). Average pressure readings and vital signs with standard deviations are noted in the table below:

  Paw cm H20 PEEP cm H20 IPV PIP cm H20 IPV PEEP cm H20 DP cm H20 Pre Sp02 % Post Sp02 % HR pre HR post BP pre BP post
Avg 13.9 8.4 21.5 7.1 14.4 93.5 96.6 138.3 143.5 93.6/ 54.8 93.5/ 56.4
StD 2.4 1.6 3.9 2.7 3.3 4.22 3.8 18.7 21.7 16.1/ 13.9 18.9/ 14.5

Conclusion: Based on this case series, addition of adjustable PEEP valve maintained higher mean airway pressures and improved oxygenation without clinical side effects or hemodynamic instability to the patients.

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