Nichtinvasive Beatmung (NIV) mittels eines Kompakt-CPAP-Systems zur Behandlung postoperativer Hypoxämien im Aufwachraum

In most cases recovery from elective surgery is usually fast and uncomplicated, but postoperative hypoxemia complicates between 30% and 50% of cases. Principal reasons of postoperative hypoxemia (SpO2<93%) in the post anesthesia care unit (PACU) are aftereffects of anesthesia, consequences of higher abdominal surgery and mechanical ventilation. Atelectasis and decreasing FRC impairs pulmonary gas exchange. These changes begin after induction of anesthesia and persist in the postoperative period. Oxygen may be required while recovering in the PACU for a few hours in many cases. Pulmonary impairment can impact patients recovery encourages the incurrence of postoperative pulmonary complications. Continuous positive airway pressure may improve postoperative lung mechanics and reduce postoperative complications in patients undergoing elective surgery. To determine the clinical effectiveness of compact-CPAP-devices by EzPAPTM-facemask for supportive breath control using postoperatively in the PACU in compared with standard treatment (oxygen delivering by a face mask) in patients who develop acute hypoxemia after surgery. The EzPAP (DHD Healthcare, Wampsville, NY) is a noninvasive Positive Airway Pressure Therapy System device for lung expansion therapy and provides positive pressure during the total respiratory cycle. Observational study conducted between November 2009 and January 2010 in the PACU of the Department of Anaesthesiology, University Hospital Aachen, RWTH Aachen, Germany. Consecutive patients who developed hypoxemia (SpO2<93%) after elective surgery directly after arrival in the PACU. Interventions in total 206 patients included. All patients received oxygen for one hour directly after arrival in the PACU. In both groups a 30-minute treatment-free interval followed and after 24 h post-therapeutically patients have been visited with a completing survey and SpO2 check. In the first study month patients were assigned to receive oxygen only (Control-group, n =101) by a conventional mask. In the second study month patients were assigned to receive oxygen by an EzPAP-devices (EzPAP-group, n = 105). The patients laid out with EzPAP-devices resp. with oxygen mask. For each patient SpO2-course, heart-and breathing rate, MAP, mask acceptance, general condition and supervision of respiration have been evaluated at fixed time points in all study phases. In additional postoperative complications (Pneumonia, SIRS/Sepsis, wound infection) and hospital lengths of stay have been evaluated. The primary end point was the improvement of oxygen saturation at the time of discharge of PACU. Secondary end points were number of patients liable to oxygen in the treatment-free interval, incidence of postoperative complications, hospital lengths of stay and mask acceptance. Patients who received oxygen by an EzPAP-device had a statistically significant faster oxygen saturation improvement after 0.5 minutes (P<0.05) treatment, significantly less patients required additional oxygen after the oxygen therapy phase (P=0.03, 25 vs. 41 patients) and showed a significantly higher SpO2 at the end of treatment-free interval (P=0.03, 94.6±2.3% [MW±SD] N=80 vs. 93.4±4.5% [MW±SD] N=60) and at the moment of discharge from PACU (P