Serial estimations of blood lactate predict postoperative outcome in cancer patients undergoing head and neck surgeries

To determine predictability of serial estimations of blood lactate levels for postoperative outcome of head and neck cancer patients and determine validity of single versus serial estimations for accurate prediction of outcome.The study included 322 cancer patients assigned for major head and neck surgeries and admitted to ICU. Data collection included age, sex, and associated comorbidities, and clinical status was determined using APACHE II score. Arterial lactate was measured at time of admission (T0), and 8-hourly (T8, T16, T24), and percentage of change of blood lactate level was calculated versus T0 level. Patients were categorized as survivor and non-survivors, and among each group, patients were categorized according to estimated level of blood lactate into four categories.The mean of APACHE score at ICU admission was 16.6 ± 3.1, and mean duration of ICU and hospital stay was 3.2 ± 1.2 and 19.3 ± 5.5 days, respectively. Fifty-two patients died for postoperative mortality rate 16.1%. Non-survivors were significantly older and had significantly higher APACHE score and significantly longer ICU and hospital stay. At admission blood lactate level was significantly higher in non-survivors compared to survivors. All patients showed progressive increase of blood lactate level, but non-survivors showed significantly higher frequency of elevated blood lactate strata compared to survivors with significantly higher difference between both groups at T8, T16, and T24. There was positive significant correlation between high at admission blood lactate level and APACHE score. Regression analysis defined % of change of blood lactate at T16, high APACHE score, high at admission blood lactate and old age as specific predictors for postoperative mortality in descending order of specificity. Serial estimations of blood lactate are conclusive test for follow-up of patients undergoing major surgical procedures requiring ICU admission. Combined high APACHE score and percentage of change of blood lactate could discriminate survivors from non-survivors especially 16-h after ICU admission.