The Science Journal of the American Association for Respiratory Care

2006 OPEN FORUM Abstracts

A COMPARISON OF POSITIVE AIRWAY PRESSURE AND VOLUME EXPANSION THERAPY IN THE PREVENTION AND TREATMENT OF ATELECTASIS IN THORACIC AND ABDOMINAL SURGERY PATIENTS

- David Mussetter, BA, RRT, Tim Frymyer, BS, RRT, Mike Trevino, MS, RRT, Gary Weinstein, MD, FCCP, Presbyterian Hospital of Dallas, Dallas, Texas

Background: Our hospital is a 903-bed acute care teaching facility in a major metropolitan area. Our respiratory therapy department works under a protocol driven clinical practice model whereby the therapist evaluates, orders, modifies, and discontinues therapy. Upon reviewing the body of literature contrasting positive airway pressure therapy with volume expansion therapy, we determined there was sufficient evidence to warrant a change in our treatment for the prevention and reversal of atelectasis. This change was made to the group of patients felt to be at high risk. We now seek to discern what significance this change in treatment methodology has made.

Method: All patient data was collected retrospectively. Patients were randomly selected from a three month period, two to four months before the introduction of positive expiratory pressure (PEP) and intermittent use of continuous positive airway pressure (iCPAP). This first group of patients received incentive spirometry (IS) and/or intermittent positive pressure breathing (IPPB) per our respiratory therapy protocol. A second group of patients was randomly selected from a three month period, four to six months after the initiation of PEP and/or iCPAP. Each patient in both groups underwent thoracic or non-laparoscopic abdominal surgery. There were 18 patients excluded due to: A) no comparison data for CXR or oxygenation [5], B) no respiratory therapy treatment within 24 hours of extubation [1], C) requiring > 24 hours of mechanical ventilation post-operatively [9], D) experiencing more than one surgery during their stay [2], or E) not being initially admitted for surgery [1]. Patient data collected include age, sex, obesity, smoking status, anesthesia type and length, post-operative ventilatory status, occurrence of pre-operative instruction, pain management, length of stay (LOS), expected LOS, DRG designation, ambulation, CXR results, oximetry, and number and type of treatments received.  

Results: The two patient populations were demographically well correlated (0.994) and LOS did not differ significantly. Other clinical outcome criteria presented as follows:

  IS / IPPB Group  n = 41 PEP / iCPAP Group  n = 39
CXR deterioration POD 0 - discharge 46%  n = 35   3%  n = 31
CXR deterioration POD 0 - 1 31%  n = 29   3%  n = 29
CXR deterioration POD 1 - discharge 22%  n = 27   0%  n = 26
SaO2 decline from baseline post-op SaO2 to POD 1 38%  n = 37 26%  n = 38
SaO2 decline from baseline post-op SaO2 to POD 2 36%  n = 28 31%  n = 35
SaO2 decline from baseline post-op SaO2 to POD 3 47%  n = 19 35%  n = 31


In addition, it has been empirically reported that patients experienced less pain using PEP versus IS or IPPB, leading to improved compliance.

Conclusion: PEP and/or iCPAP seems to demonstrate an objective improvement over IS and/or IPPB when comparing CXR and SaO2 data. Whether these results are statistically or clinically significant is not yet clear given the small sample size. Despite this, the early data points favorably towards the utilization of PEP and/or iCPAP. If this holds true, benefits might also be derived from patients having a higher compliance rate with the less painful (assumed) PEP therapy. Further study may provide more definitive answers.

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