Early postoperative use of CPAP reduces need for unplanned IPPV in elective vascular patients

Introduction

Respiratory failure is a well-known complication of aortic aneurysm surgery. We describe the impact of a protocol, using CPAP after elective surgery to reduce the need for unplanned invasive ventilation.

Methods

In 2012 we introduced a CPAP protocol for patients undergoing elective aortic aneurysm surgery, either open (AAA) or as an endovascular repair (EVAR). According to pre-existing risk factors (see Table 1) and arterial blood gas analysis in the anaesthetic room, they were assigned to two alternative options on the ITU: prophylactic CPAP for 9 hours in each of the first two postoperative nights or oxygen via face mask. CPAP was applied at any time in the patients stay, if their P/F ratio dropped below 40. Criteria to stop CPAP were also predefined. Previously, CPAP was initiated at the discretion of nursing staff, P/F ratios were not utilised.

Table 1 Criteria for the use of prophylactic CPAP.

Results

We compare patient cohorts in the years 2010 and 2011 (pre protocol) with 2013 and 2014 (post protocol). Results are reported as the split between open surgery and endovascular repair. Table 2 presents requirements for invasive ventilation (IPPV) and length of stay (LOS) for both patient groups.

Table 2 IPPV requirements and length of stay data 2010 to 2011 2013 to 2014.

Conclusion

There is a clear reduction in the need for unplanned IPPV in both patient groups. An audit in 2013 showed incomplete protocol adherence in the ITU, therefore benefits may be underestimated.