Title : Prevention of acute desaturation in patients with intra-abdominal hypertension
INTRODUCTION Portable lung ventilators or AMBU bags with PEEP valves are widely used during patient transfer from SICU to OR and from OR to SICU. Acute desaturation during this period is a well-known problem necessitating the use of recruitment maneuvers, which, unfortunately, can further damage patient’s lungs. We hypothesized that mentioned desaturation is due to sudden equalization of intrapulmonary and atmospheric pressures with loss of PEEP and development of atelectasis in unstable lung units. For prevention of this problem, we proposed clamping ETT during brief period of disconnection and reconnection to the breathing circuit.
OBJECTIVES To find a simple and inexpensive way for prevention of arterial desaturation during patient transfer from SICU to OR or from OR to SICU.
METHODS This was a double blind randomized study of 121 SICU patients having major abdominal procedures and being on full mechanical ventilation with PEEP. Patients were randomly assigned to two groups: those who had their ETT clumped during disconnection and reconnection to breathing circuit and those with ETT left unclamped during disconnection and reconnection. Main endpoint was frequency of desaturation > 5% from baseline after disconnection and reconnection to the breathing circuit.
RESULTS Desaturation was significantly more prevalent in patients who did not have their ETT clamped during disconnection and reconnection to the breathing circuit: 86.51% vs. 23.14% (χ2=39.433, df=1, p<0. 001). Accordingly, patients with unclamped ETT had higher frequency of using recruitment maneuvers (Tab 1). Demographics, BMI, ASA, APACHE score, SOFA were not significantly different between groups.
CONCLUSION A brief period of equalization of intrapulmonary and atmospheric pressures is enough to cause atelectasis in unstable lung units with profound desaturation necessitating the application of recruitment maneuvers.