88 A Retrospective Review of the Use of Airway Pressure Release Ventilation (APRV) in the Burn Operating Room

Abstract

Airway Pressure Release Ventilation (APRV) is the preferred mode of mechanical ventilation for the initial treatment of inhalation injury at our burn center. APRV improves alveolar recruitment, thus improving oxygenation. However, general anesthesia cannot be administered when patients are on APRV, resulting in frequent interruptions in the circuit and subsequent alveolar derecruitment with prolonged periods of sub-optimal ventilation post-operatively. Total IV anesthesia (TIVA) allows for the continued use of APRV perioperatively. The purpose of this study was to assess the safety and efficacy of APRV during surgery. This was a retrospective chart review of patients that remained on APRV during surgery over a 3-year period. Demographic, injury, ventilator, and outcome data were collected. Pre (PRE) and post-operative (POST) FIO2, Rate (set & spontaneous), Tidal Volume (TV), Minute Volume (MV), P High/Low, T High/Low, and Mean Airway Pressures (MAP) were compared for each surgery. The charts of 55 patients were reviewed, mean age was 45 years, the majority were male (75%) and 9% had pre-existing pulmonary disease. The most common mechanism was flame/flash (67%) with total body surface area (TBSA) burned ranging from 0 - 92% (M 42%). Concomitant inhalation injury was present for 58% of patients. Total ventilator days (M 42.2, ±35.7), total APRV days (M 16, ±12.9). Total number of surgeries (M 9.4, ±7.94), total number of surgeries on APRV (M 3.4, ±2.65). There were 38 patients with complete PRE and POST ventilator data. Surgery 1 on APRV; there were no significant differences for FIO2, Rate, TV, MV, P High/Low, T High, MAP; POST T Low was lower (M 0.8) when compared to PRE (M 0.9), (p=0.0005). Surgery 2 (n=35), POST mean FIO2 requirements were higher; PRE (0.47) vs POST (0.57), (p=.0358). Surgery 3 (n=25) average TV was lower POST-OP; PRE-OP (630) vs POST (523), (p=.005). There were no significant differences between PRE and POST requirements for patients on APRV during surgeries 4 (n=16) and 5 (=13). No patients suffered complications pre, peri or post-operatively when on APRV. Overall inpatient mortality was 35%. Of survivors, 92% required transfer to a post-acute care facility. APRV can be continued intra-operatively with the use of TIVA. This retrospective study demonstrates that TIVA and intra-operative APRV are safe and effective. TIVA allows the continued use of APRV intra-operatively in burn patients requiring aggressive ventilator support.