Incidence of low central venous oxygen saturation after standard postoperative intensive care management

Introduction

Targeted early postoperative management of high-risk surgical patients has been reported to be associated with a lower rate of complications and shorter hospital length of stay (HLOS) compared with conventional management. A low postoperative central venous oxygen saturation (ScVO₂) has also been shown to be associated with higher rates of complications and of HLOS for high-risk surgical patients. Benefit from early goal-directed therapy would be unlikely if 'standard' postoperative management resulted in a low incidence of patients with a low ScVO₂ in the early postoperative period.

Methods

Arterial and central venous blood gas analysis was done on admission (T1) and after 8 hours (T2) of admission to the ICU. The HLOS and the incidence of complications were determined for patients with low (<70%) or normal (≥70%) ScVO₂.

Results

Sixty-three postoperative patients were screened and 23 patients were analysed. Patients were excluded if they did not have a central line positioned in the superior vena cava or blood had not been sampled at both time points. Patients with pre-ICU HLOS > 5 days (n = 10), acute spinal cord injury (n = 3), or admitted for postoperative airway management (n = 4) were omitted. ScVO₂ was low in 7/23 patients at T2 and six of these had lower gastrointestinal surgery. The HLOS (median (IQR)) was longer in those with low ScVO₂ at T2 (17 (37.8) v 9.5 (5.0) days, P = 0.04). The incidence of complications was not different. There were no differences between the ScVO₂ groups at T2 with respect to age, gender, standard base excess, lactate, haemoglobin, mean arterial pressure or central venous pressure. The volume of colloid the two groups received in the 8-hour observation period was not different although there was a trend for the low group to receive more crystalloid (P = 0.08).

Conclusion

A significant proportion of patients had a low ScVO₂, which was associated with increased HLOS. The results provide a basis for the trial of postoperative early goal-directed therapy for high-risk surgical patients admitted to our ICU.