Intraoperative central venous oxygen saturation and patient outcome in patients undergoing major abdominal surgery

Introduction

Low central venous saturation (ScvO₂) in the post-operative period is associated with poor outcome. We examined whether intraoperative ScvO₂ is a predictor of outcome based on the postoperative morbidity survey (POMS) and length of hospital stay. The POMS is a method for describing complications associated with major surgery [1]. It comprises a nine-point survey and provides a generic measure of short-term postoperative outcome.

Methods

Prospective ScvO₂ values were collected from patients undergoing major abdominal surgery. This was done by intermittent sampling of blood obtained from the distal lumen of a central venous catheter placed in the jugular vein. The POMS was used to assess outcome on postoperative days 1, 3, 5, 8, 15 and 21 if applicable. To accommodate local practice, however, we excluded urinary catheter, pain and mobility from the POMS as it was not a true reflection of organ dysfunction in our study population. We evaluated other individual postsurgical complications as outlined in the POMS to establish whether intraoperative median, minimum and ΔScvO₂ (end of surgery value minus start of surgery value) are related to outcome.

Results

Fifty-two patients (average age 67.8, SD 12.0) were included. The Portsmouth Physiological and Operative Severity Score for the Enumeration of Mortality and Morbidity revealed a predicted morbidity of 54.2% and mortality of 3.3%. The commonest complications were gastrointestinal and infection (58.7% and 19.2%, respectively). We found no correlation between median, minimum and ΔScvO₂ with postoperative complication and length of hospital stay. However, ΔScvO₂ for patients who exhibited postoperative complication on day 3 was significantly different from the patients who did not (P = 0.035) but the actual difference was only 2%. Minimum ScvO₂ correlated weakly with high arterial lactate measured at the end of the procedure (Spearman r = 0.32, P = 0.025).

Conclusion

Intraoperative central venous saturation in patients undergoing major abdominal surgery is not related to postoperative outcome or length of hospital stay.