Prediction of Venous-arterial Carbon Dioxide Tension Difference, Lactate and Central Venous Saturation After Surgery with Circulatory Arrest
Bernd Panholzer1, Pauline Oldenburg1, Katharina Huenges1, Mohamed Salem1, Toni Jacob1, Mathis Wegner1, Jochen Cremer1, Kevin Pilarczyk2, Assad Haneya1
1UKSH Kiel, Kiel, Germany, 2Imland Klinikum, Rendsburg, Germany
BACKGROUND: Since normal or high central venous oxygen saturation (ScvO2) values cannot discriminate if tissue perfusion is adequate, integrating other markers of tissue hypoxia, such as central venous-to-arterial carbon dioxide difference (∆ pCO2) has been proposed in patients after non-cardiac surgery. It was the aim of the present study to investigate the prognostic significance of serum lactate, ∆ pCO2 and ScvO2 in patients after thoracic aortic surgery (TAS) with moderate hypothermic circulatory arrest (MHCA).
METHODS: 102 consecutive patients undergoing TAS with MHCA were prospectively enrolled. Measurements of serum lactate, ∆ pCO2 and ScvO2 in the blood were performed on admission and 6 hours after admission on ICU. Primary endpoint was 30-d-mortality; secondary outcomes included LCOS. and MACCE (LCOS, Stroke, CPR, myocardial infarction).
RESULTS: Mean age of patients was 69.1±10.9 years, 35 patients were female (34%). Non survivors were significantly older, had a higher Euro-Score and longer duration of cardiopulmonary bypass, aortic cross clamp time and cardiac arrest time. Non-Survivors were characterized by significantly higher lactate levels on admission and 6 hours after admission (initial: 7.5 ± 5.3 vs. 2.4 ± 2.2 mg/dl, p < 0.01, 6-h: 6.0 ± 4.4 vs.1.9 ± 1.7 mg/dl). In contrast, ∆ pCO2 (initial: 6.6 ± 5.1 vs. 8.5 ± 3.6 mmHg, p = n.s.; 6-h: 7.1 ±4.7 vs. 7.9 ± 54.1, p = n.s.) and ScvO2 (initial: 73.5 ± 12.2 vs. 74.2 ± 15.5 %, p = n.s.; 6-h: 71.3 ± 12.7 vs. 76.4 ± 16.8 %, p= n.s.) did not differ between survivors and non-survivors. Early lactate levels after admission were able to predict postoperative LCOS (AUC 0.871, p < 0.001), MACCE (AUC 0.879, p < 0.001) as well as mortality (AUC 0.867, p < 0.001). In contrast, ∆ pCO2 and ScvO2 showed a low predictive capacity for postoperative outcome. In the subgroup of patients with normal lactate and ScvO2 values, ∆ pCO2 was also not associated with early postoperative morbidity or mortality.
CONCLUSIONS:Early postoperative lactate levels can identify patients with high risk for morbidity and mortality after TAS with MHCA. In contrast to patients undergoing non-cardiac surgery, ∆ pCO2 is not predictive of postoperative complications or mortality.