Renal resistive index as a predictor of postoperative complications in liver resection surgery. Observational study.

Mortality after liver surgery reduced during the last three decades to less than 2%, but post-operative morbidity occurs in 20-50% of cases. Patients are often considered eligible for post-operative intensive-care unit (ICU) admission. Predicting which patients that are at higher risk could lead to a more precise perioperative management. We investigated whether renal resistive index (RRI), alone or along with other items, can predict post-operative complication after hepatic resection. All consecutive patients undergoing hepatectomy for primary or metastatic neoplasm at our Institution between February 2015 and March 2017 were enrolled. They received RRI measurement before entering in operative room and after awakening from general anesthesia. 183 Patients were enrolled. High surgical invasiveness, surgery time > 360 min, pre-operative RRI and postoperative serum lactate clearance < - 6%, showed to be associated with postoperative complications. Pre-operative RRI, complex liver resection, long-lasting surgery and poor lactate clearance (cLac) close to awakening from general anesthesia, all together may permit to classify the risk of post-operative adverse outcome after hepatic resection surgery.

Serum lactate in liver resection with intermittent Pringle maneuver: the "square-root- shape.

BACKGROUND: Serum lactate (sLac) concentration during liver resection with intermittent hepatic hilum clamping (i.e. Pringle maneuver, PM) was retrospectively investigated. METHODS: A total of 133 patients who underwent liver resection were enrolled. We analyzed the sLac peri-operatively. Correlations were searched between the PM and lactatemia and its variations (i.e. lactate clearance, cLac) and other factors which it might be related to. Lactatemia in triplicate intraoperatively was recorded, just after the awakening, and 1 and 2 h later. The cLac between two consecutive measurements [(sLac1 - sLac2 )/sLac1 ] was computed. RESULTS: A reliable dependence of sLac was found from the cumulative PM. More than 76 min of cumulative Pringle Time (cPT) exposed patients to a worse cLac at the end of the resection phase (P < 0.0001). We found cPT >76 min, global operation time >365 min and bleeding >225 ml to be predictors of hyperlactatemia (sLac >4 mmol/L). Normal liver resulted as a risk factor for hyperlactatemia and steatosis was not (P = 0.030 vs. P = 0.325). Finally, cLac showed a "square-root- shape, just like the mathematical operation sign. CONCLUSIONS: Lactatemia during liver resection depends on the duration of PM, bleeding and the duration of the operation. Normal liver may expose the patient to the risk of hyperlactatemia.

May Renal Resistive Index be an early predictive tool of postoperative complications in major surgery? Preliminary results.

BACKGROUND: Patients who undergo high-risk surgery represent a large amount of post-operative ICU-admissions. These patients are at high risk of experiencing postoperative complications. Renal Resistive Index was found to be related with renal dysfunction, hypertension, and posttraumatic hemorrhagic shock, probably due to vasoconstriction. We explored whether Renal Resistive Index (RRI), measured after awakening from general anesthesia, could have any relationship with postoperative complications. METHODS: In our observational, stratified dual-center trial, we enrolled patients who underwent general anesthesia for high-risk major surgery. After awakening in recovery room (or during awakening period in subjects submitted to cardiac surgery) we measured RRI by echo-color-Doppler method. Primary endpoint was the association of altered RRI (>0.70) and outcome during the first postoperative week. RESULTS: 205 patients were enrolled: 60 (29.3%) showed RRI > 0.70. The total rate of adverse event was 27 (18.6%) in RRI ≤ 0.7 group and 19 (31.7%) in RRI > 0.7 group (P = 0.042). Significant correlation between RRI > 0.70 and complications resulted in pneumonia (P = 0.016), septic shock (P = 0.003), and acute renal failure (P = 0.001) subgroups. Patients with RRI > 0.7 showed longer ICU stay (P = 0.001) and lasting of mechanical ventilation (P = 0.004). These results were confirmed in cardiothoracic surgery subgroup. RRI > 0.7 duplicates triplicates the risk of complications, both in general (OR 2.03 93 95% CI 1.02-4.02, P = 0.044) and in cardiothoracic (OR 2.62 95% CI 1.11-6.16, P = 0.027) population. Furthermore, we found RRI > 0.70 was associated with a triplicate risk of postoperative septic shock (OR 3.04, CI 95% 1.5-7.01; P = 0.002).