Arterial to jugular-bulb lactate difference in patients undergoing elective brain tumor craniotomy.

Hyperlactatemia is common during tumor craniotomy, but the underlying pathophysiology is unclear. This study measured simultaneous arterial and jugular-bulb lactate concentrations in patients undergoing brain tumor craniotomy to investigate the hypothesis that hyperlactatemia was associated with a net cerebrovascular lactate input. In 20 patients, arterial and jugular-bulb blood was collected hourly from the start of surgery to 6 h postoperatively for measurement of lactate, glucose, and oxygen concentration. For each marker, data were analyzed using a linear mixed-effects model with jugular-bulb concentration as dependent variable, arterial concentration as fixed effect, and patient as random effect. Furthermore, we generated regression lines between arterial and jugular-bulb concentrations. The slope of the regression line between arterial and jugular-bulb lactate was 0.95 (95% CI 0.93-0.97, R2 = 0.98), indicating that increasing arterial lactate levels were associated with an increasingly positive net cerebrovascular balance (net input). The line crossed the identity line at 2.86 (95% CI 0.57-5.16) mmol/L, indicating that lower levels of lactate were associated with a negative net cerebrovascular balance (net output). This suggests a switch from net lactate output during normolactatemia towards net input during hyperlactatemia. Hyperlactatemia in tumor-craniotomy patients probably does not originate from the brain.

Relation Between Multiplication of Venous Carbon Dioxide Partial Pressure (PvCO2) and the Ratio of Gas Flow to Pump Flow (Ve/Q) with Hyperlactatemia During Cardiopulmonary Bypass.

BACKGROUND: The incidence of hyperlactatemia due to hypoperfusion during cardiopulmonary bypass (CPB) increases morbidity. Carbon dioxide production during CPB is one of the lactate production markers, in addition to other markers such as delivery oxygen (DO2), oxygen consumption (VO2), mixed vein oxygen saturation (SvO2), and oxygen extraction ratio (O2ER). METHOD: This observational analytic study was conducted on 40 adult cardiac surgery patients using a CPB machine. Initial lactate is taken when entering CPB and final lactate is examined 15 min after coming off bypass. The values of DO2, VO2, SvO2, VCO2, respiratory quotient (RQ), DO2/VCO2, PvCO2 × Ve/Q were calculated from the results of blood and venous gas analysis 1 h after entering CPB in the nadir of core temperature and lowest pump flow. RESULT: The multivariate test showed that the value of PvCO2 × Ve/Q was more effective than other oxygenation and carbon dioxide parameters in predicting an increase in the percentage of lactate. Each increase of 1 mmHg PvCO2 ×× Ve/Q can predict a final lactate increase of 29% from the initial lactate. The high PvCO2 × Ve/Q value is also the strongest correlation factor for the incidence of hyperlactatemia after CPB (final lactate >3 mmol/L). The cutoff value of this marker is >19.3 mmHg, which has a sensitivity of 100% and a specificity of 55.6% with a strong correlation value. CONCLUSION: The PvCO2 × Ve/Q value proved to be one of the significant markers in predicting hyperlactatemia during cardiac surgery using CPB.

Prognostic value of hyperlactatemia and lactate clearance in septic patients with hematological malignancies.

BACKGROUND: The coexistence of sepsis and hematological malignancies increases patient vulnerability, revealing the need for precise prognostic markers. This study explores the prognostic significance of lactate levels and clearance in septic patients with hematological malignancies. MATERIALS AND METHODS: A retrospective cohort study from January 2016 to December 2019 in a tertiary hematological intensive care unit (ICU) included 167 adults with hematological malignancies and sepsis. The relationship between lactate levels, hyperlactatemia, lactate clearance, and ICU outcomes was investigated. ICU survivors and non-survivors were compared to identify the factors affecting ICU mortality. RESULTS: Patients were primarily with lymphoma and acute leukemia (66%) and had frequent hyperlactatemia (64%) on ICU admission. ICU non-survivors demonstrated higher lactate levels and hyperlactatemia frequency at various time points (0, 6, and 12 h) than survivors. Lactate clearance and liver function tests did not differ significantly between the two groups. Invasive mechanical ventilation [OR (95% confidence interval-CI): 20.4 (2.4-79.8), p < 0.01], requirement of vasopressors [OR (95% CI): 5.6 (1.3-24.5), p < 0.01], lactate level at the 6th hour [OR (95% CI): 1.51 (1.1-2.07), p = 0.01], and APACHE II score (OR (95% CI): 1.16 (1.01-1.34), p = 0.05) were independent risk factors for ICU mortality. The Area Under the Curve for APACHE II score and lactate level at the 6th hour were 0.774 (95% CI: 0.682-0.866) and 0.703 (95% CI: 0.602-0.804), respectively. CONCLUSION: While elevated lactate levels correlate with mortality rate and lactate level at the 6th hour is an independent risk factor for mortality, the absence of a significant difference in lactate clearance challenges traditional assumptions. These results question the commonly accepted perspective regarding lactate dynamics in sepsis among individuals with hematological malignancies. ORAL PRESENTATION: Inci K, et al. "Hyperlactatemia, lactate clearance and outcome in critically ill patients with hematological malignancies," 22nd international intensive care symposium, 2019.

Comparison of 4% Albumin and Ringer's Acetate on Hemodynamics in On-pump Cardiac Surgery: An Exploratory Analysis of a Randomized Clinical Trial.

OBJECTIVES: Compare hemodynamics between 4% albumin and Ringer's acetate. DESIGN: Exploratory analysis of the double-blind randomized ALBumin In Cardiac Surgery trial. SETTING: Single-center study in Helsinki University Hospital. PARTICIPANTS: We included 1,386 on-pump cardiac surgical patients. INTERVENTION: We used 4% albumin or Ringer's acetate administration for cardiopulmonary bypass priming, volume replacement intraoperatively and 24 hours postoperatively. MEASUREMENTS AND MAIN RESULTS: Hypotension (time-weighted average mean arterial pressure of <65 mmHg) and hyperlactatemia (time-weighted average blood lactate of >2 mmol/L) incidences were compared between trial groups in the operating room (OR), and early (0-6 hours) and late (6-24 hours) postoperatively. Associations of hypotension and hyperlactatemia with the ALBumin In Cardiac Surgery primary outcome (≥1 major adverse event [MAE]) were studied. In these time intervals, hypotension occurred in 118, 48, and 17 patients, and hyperlactatemia in 313, 131, and 83 patients. Hypotension and hyperlactatemia associated with MAE occurrence. Hypotension did not differ between the groups (albumin vs Ringer's: OR, 8.8% vs 8.5%; early postoperatively, 2.7% vs 4.2%; late postoperatively, 1.2% vs 1.3%; all p > 0.05). In the albumin group, hyperlactatemia was less frequent late postoperatively (2.9% vs 9.1%; p < 0.001), but not earlier (OR, 22.4% vs 23.6%; early postoperatively, 7.9% vs 11.0%; both p > 0.025 after Bonferroni-Holm correction). CONCLUSIONS: In on-pump cardiac surgery, hypotension and hyperlactatemia are associated with the occurrence of ≥1 MAE. Compared with Ringer's acetate, albumin did not decrease hypotension and decreased hyperlactatemia only late postoperatively. Albumin's modest hemodynamic effect is concordant with the finding of no difference in MAEs between albumin and Ringer's acetate in the ALBumin In Cardiac Surgery trial.

Preadmission metformin use increased the incidence of hyperlactatemia at admission and 30-day in-hospital mortality among T2D patients with heart disease at high risk of hypoxia.

BACKGROUND: Surprisingly, despite the high prevalence of metformin use in type 2 diabetes (T2D) patients with heart disease, limited safety data is available regarding metformin use in patients with acute and critical heart disease. METHODS: In this single-center retrospective study, patients admitted to the cardiology department for heart failure (HF) or acute coronary syndrome (ACS) between December 2013 and December 2021 and who underwent arterial blood gas analysis at admission with an estimated glomerular clearance rate of ≥45 ml/min/1.73 m2 were identified. The incidences of hyperlactatemia, acidosis, and 30-day in-hospital mortality were compared between preadmission metformin users and nonusers. RESULTS: Of 526 admissions, 193/193 metformin users/nonusers were selected in a propensity score-matched model. Metformin users had greater lactate levels (2.55 ± 2.07 mmol/l vs. 2.00 ± 1.80 mmol/l P < 0.01), a greater incidence of hyperlactatemia [odds ratio (OR) = 2.55; 95% confidence interval (CI), 1.63-3.98; P < 0.01] and acidosis (OR = 1.78; 95% CI, 1.00-3.16; P < 0.05) at admission and a greater incidence of in-hospital mortality (OR = 3.83; 95% CI, 1.05-13.94; P < 0.05), especially those with HF/acute myocardial infarction, elderly age, or without preadmission insulin use. CONCLUSIONS: Our results suggest that, compared to metformin nonusers, preadmission use of metformin may be associated with a greater incidence of hyperlactatemia and acidosis at admission and greater 30-day in-hospital mortality among T2D patients with HF or ACS at high risk of hypoxia, particularly those without preadmission insulin use. The safety of metformin in this population needs to be confirmed in prospective controlled trials.

Risk factors and in-hospital mortality of postoperative hyperlactatemia in patients after acute type A aortic dissection surgery.

BACKGROUND: Hyperlactatemia may be caused by increased production due to tissue hypoxia or non-hypoxia. The aim of this study was first to identify risk factors for postoperative hyperlactatemia (POHL) after Stanford type A acute aortic dissection surgery (AADS) and construct a predictive model, and second to evaluate the impact of POHL on prognosis. METHODS: This retrospective study involved patients undergoing AADS from January 2016 to December 2019 in Wuhan Union Hospital. Multivariate logistic regression analysis was performed to identify independent risk factors for POHL. A nomogram predicting POHL was established based on these factors and was validated in the original dataset. The receiver operating characteristic curve was drawn to assess the ability of postoperative lactate levels to predict the in-hospital mortality. RESULTS: A total of 188 patients developed POHL after AADS (38.6%). Male gender, surgery history, red blood cell transfusion and cardiopulmonary bypass time were identified as independent predictors. The C-index of the prediction model for POHL was 0.72, indicating reasonable discrimination. The model was well calibrated by visual inspection and goodness-of-fit test (Hosmer-Lemeshow χ2 = 10.25, P = 0.25). Decision and clinical impact curves of the model showed good clinical utility. The overall in-hospital mortality rate was 10.1%. Postoperative lactate levels showed a moderate predictive power for postoperative in-hospital mortality (C-index: 0.72). CONCLUSION: We developed and validated a prediction model for POHL in patients undergoing AADS, which may have clinical utility in personal risk evaluation and preventive interventions. The POHL could be a good predictor for in-hospital mortality.

The risk factors of intraoperative hyperlactatemia in patients undergoing laparoscopic colorectal surgery.

AIM: The aim of this study is to determine the incidence of intraoperative hyperlactatemia and its risk factors in patients undergoing laparoscopic colorectal surgery. MATERIAL AND METHODS: We retrospectively enrolled 75 patients who underwent laparoscopic resection for colorectal cancer. Initial lactate levels were determined from blood gas analysis before the incision. The end lactate values were recorded after the termination of the pneumoperitoneum. Hyperlactatemia defined as lactate levels between 2 mmol/L and 5 mmol/L without evidence of acidosis. The patients were divided into two groups as normolactatemia and hyperlactatemia according to lactate values at the end of the surgery. RESULTS: Of the 75 patients, 45 (60.0%) had higher lactate levels than normal at the end of the surgery. The median age of the study population was 62 (24-84) years. Forty (53.3%) of the patients were male. Most of the patients in the study had colon cancer origin [56 cases (74.7%)]. Univariate logistic regression analysis for a possible independent risk factor in terms of hyperlactatemia showed that Charlson comorbidity index (CCI) ≥ 3, body mass index (BMI) ≥ 30 kg/m2, the operative time, and the tumor size were significant (p < 0.05). Multivariate analysis found that only BMI ≥ 30 kg/m2 and the operative time were significant (p = 0.004, and p < 0.001, respectively). CONCLUSION: According to our work, obesity (BMI ≥ 30 kg/m2) and the operative time in laparoscopic colorectal surgery were independent risk factors for intraoperative hyperlactatemia at the end of the operation. Therefore, clinicians should be vigilant about the inevitable consequences of surgery by making appropriate preparation. KEY WORDS: Colorectal cancer, Lactate, Hyperlactatemia, Laparoscopy.

Hyperlactatemia After Intracranial Tumor Surgery Does Not Affect 6-Month Survival: A Retrospective Case Series.

BACKGROUND: Patients undergoing neurosurgery frequently exhibit hyperlactatemia. The aim of this study was to identify factors associated with hyperlactatemia and assess how hyperlactatemia impacts survival and hospital length of stay after intracranial tumor surgery. MATERIALS AND METHODS: This retrospective cohort study included 496 adult patients that underwent surgery between January 1, 2014 and December 31, 2015. We evaluated patient characteristics, surgery characteristics, pH, lactate, and blood glucose from blood samples collected on admission to the high-dependency unit and the morning after surgery, and 6-month outcome data. RESULTS: Hyperlactatemia (>2.0 mmol/L) occurred in >50% of patients, but only 7.7% had acidosis. Postoperative hyperlactatemia was not correlated with 6-month survival (P=0.987), but was correlated with (median [interquartile range]) longer hospital stays (6 [4 to 8.5] d vs. 5 [4 to 8] d; P=0.006), longer surgery duration (4:53 [4:01 to 6:18] h:min vs. 4:28 [3:33 to 5:53] h:min; P=0.001), higher dexamethasone dose (16 [16 to 35] mg vs. 16 [16 to 20] mg; P<0.001), and higher blood glucose concentration (8.4 [7.5 to 9.6] mmol/L vs. 8.0 [7.1 to 8.9] mmol/L; P<0.001). Patients that received total intravenous anesthesia developed hyperlactatemia less frequently than those that received balanced anesthesia with inhalational agents (48.4% vs. 61.5%, P=0.008). Hyperlactatemia was not associated with increased postoperative neurological deficits or the need for rehabilitation therapy. CONCLUSIONS: Hyperlactatemia was common after intracranial tumor surgery. It did not influence 6-month outcomes but was associated with longer hospital length of stay. Several potential causative factors for hyperlactatemia were identified.

Hyperlactataemia with acute kidney injury following community assault: cause or effect?

BACKGROUND: Crush injury is a common presenting clinical problem in South African trauma patients, causing acute kidney injury (AKI). It has been theorised previously that the AKI was not due to an anaerobic phenomenon. A previous local study noted the presence of a mild hyperlactataemia among patients with crush syndrome, but the significance and causes of this was not fully explored. This study aimed to examine the incidence of hyperlactataemia in patients with crush syndrome presenting to a busy emergency department (ED) in rural South Africa. METHOD: The study was conducted at Edendale Hospital in KwaZulu-Natal province in South Africa from 1 June 2016 to 31 December 2017. All patients from the ED who had sustained a crush injury secondary to a mob assault were included in the study. Patients with GCS on arrival of < 13 or polytrauma were excluded from analysis. The primary outcome of interest was the presence of hyperlactataemia (> 2.0mmol/L) on presentation. The Kidney Disease Improving Global Outcomes (KDIGO) criteria were used to diagnose and stage AKI as a secondary outcome. RESULTS: A total of 84 patients were eligible for analysis. Sixty-nine (82%) patients presented with hyperlactataemia. The median serum lactate was 4.9mmol/L (IQR 2.3-7.2mmol/L). Fifteen (18%) patients were diagnosed with AKI on presentation according to serum creatinine. Ten patients were diagnosed as Stage 1, three were Stage 2 and two Stage 3 AKI respectively. There was no difference in the incidence of AKI in patients with or without hyperlactataemia (p = 0.428). Time from injury to presentation was a median 365 minutes (IQR 180-750 minutes). Six (7%) patients were admitted to high care unit and nine (11%) were admitted to the intensive care unit (ICU). No patients died within 48 hours of admission. Two patients received renal replacement therapy during the first 48 hours of admission to hospital. CONCLUSION: Hyperlactataemia is a common feature of patients presenting to the ED following crush syndrome secondary to beatings received during interpersonal violence. The origin of this hyperlactataemia is currently unknown. Further research needs to be conducted into the origin of the hyperlactataemia and its clinical significance. In this cohort, the utilisation of RRT was low but the incidence of AKI was high and developed rapidly following the injury. The utilisation of RRT also needs to be further studied in larger patient populations in South Africa to make local clinical recommendations for use.

Hyperlactatemia and Patient Outcomes After Pediatric Cardiac Surgery.

Elevated serum lactate level, or hyperlactatemia, is often associated with alterations in tissue perfusion, increased risk for complications in the postoperative period, and patient mortality. Measuring lactate levels is a relatively simple and noninvasive method of obtaining useful data about an impending clinical deterioration in a seemingly hemodynamically stable patient. This article evaluates the current practice of measuring lactate levels in pediatric patients after cardiac surgery and the association between these levels and patient outcomes. The article addresses periods of increased risk for decreased perfusion, the critical postoperative period, use of lactate measurements in conjunction with a risk scoring system for pre-and postoperative congenital heart disease patients, and the implications of elevated lactate levels in nursing practice.

The incidence and outcome of hyperlactatemia in patients admitted to the intensive care unit after elective surgery.

BACKGROUND: Although hyperlactatemia is often developed in critically ill patients, it is unclear whether hyperlactatemia is associated with poor prognosis for surgical ICU (SICU) patients. METHODS: We performed a retrospective analysis in an academic hospital in Tokyo. The maximum lactate was defined as the highest value within the SICU stay. The primary outcome was the composite outcome of in-hospital mortality, re-admission to the SICU or admission to the general ICU and emergency reoperation. RESULTS: There were 3421 patients with normal lactate (<2 mmoL/L), 1642 with moderate hyperlactatemia (2-3.9 mmoL/L) and 299 with severe hyperlactatemia (≥4 mmoL/L). The composite outcome occurred in 6.2%. In multivariable logistic regression analysis, the odds ratio for the composite outcome was 1.49 for moderate hyperlactatemia and 1.42 for severe hyperlactatemia. CONCLUSIONS: The odds ratio was similar between moderate and severe hyperlactatemia, so the cause and meaning of hyperlactatemia might be different among patients with elective surgery.

Perioperative Hyperlactemia Is a Poor Predictor of Outcome in Patients Undergoing Surgery for Acute Type-A Aortic Dissection.

OBJECTIVE: In patients presenting with acute type-A aortic dissection (aTAAD), lactic acid measurement is a frequently used analysis for diagnosis of acute ischemia, which may have a dismal prognosis. The aim of the current study was to determine the performance of perioperative arterial lactic acid measurements in predicting outcome in aTAAD patients. DESIGN: Retrospective, observational study. SETTING: Cardiothoracic surgery unit at a tertiary-level hospital. PARTICIPANTS: The study involved 285 consecutive patients undergoing surgery for aTAAD. INTERVENTIONS: Preoperative and postoperative lactic acid levels were measured and evaluated together with clinical data related to outcome, including in-hospital and 1-year mortality. MEASUREMENTS AND MAIN RESULTS: Altogether, 37 patients (13%) died during the index hospital admission, and survival was 84.4 ± 2.2 at 1 year. Preoperative cardiac malperfusion (odds ratio [OR] 3.1; 95% confidence interval [CI] 1.3-7.3) and cerebral malperfusion (OR 2.6; 95% CI 1.2-5.6) were associated significantly with poorer 1-year survival. The area under the curve (AUC) for in-hospital and 1-year mortality in relation to preoperative lactic acid levels was 0.684 and 0.673, respectively, corresponding to a lactic acid cut-off for in-hospital mortality of 2.75 mmol/L (sensitivity 56%; specificity 72%) and a cut-off for 1-year mortality of 2.85 mmol/L (sensitivity 48%; specificity 74%). The AUC for in-hospital and 1-year mortality in relation to lactic acid levels measured postoperatively on arrival at the intensive care unit was 0.582 and 0.498, respectively. CONCLUSION: Although hyperlactemia in aTAAD indicates an increased risk of postoperative mortality, the sole use of lactic acid levels as a tool for accurate assessment of postoperative mortality is inadvisable due to its poor discriminatory performance.

Clinical use of plasma lactate concentration. Part 2: Prognostic and diagnostic utility and the clinical management of hyperlactatemia.

OBJECTIVE: To review the current literature pertaining to the use of lactate as a prognostic indicator and therapeutic guide, the utility of measuring lactate concentrations in body fluids other than blood or plasma, and the clinical management of hyperlactatemia in dogs, cats, and horses. DATA SOURCES: Articles were retrieved without date restrictions primarily via PubMed, Scopus, and CAB Abstracts as well as by manual selection. HUMAN AND VETERINARY DATA SYNTHESIS: Increased plasma lactate concentrations are associated with increased morbidity and mortality. In populations with high mortality, hyperlactatemia is moderately predictive in identifying nonsurvivors. Importantly, eulactatemia predicts survival better than hyperlactatemia predicts death. Consecutive lactate measurements and calculated relative measures appear to outperform single measurements. The use of lactate as a therapeutic guide has shown promising results in people but is relatively uninvestigated in veterinary species. Increased lactate concentrations in body fluids other than blood should raise the index of suspicion for septic or malignant processes. Management of hyperlactatemia should target the underlying cause. CONCLUSION: Lactate is a valuable triage and risk stratification tool that can be used to separate patients into higher and lower risk categories. The utility of lactate concentration as a therapeutic target and the measurement of lactate in body fluids shows promise but requires further research.

Prognostic Value of Hyperlactatemia and Lactate Clearance After Mitral Valve Surgery.

OBJECTIVES: Blood lactate is frequently used to guide management in critically ill patients. In patients undergoing mitral valve surgery, an elevated lactate level is frequently observed; however, overall mortality is low. The authors hypothesized that hyperlactemia is not a useful predictor of poor outcomes in this patient population. The main aim of this study was to explore how blood lactate level and lactate clearance are associated with 30-day mortality and major adverse events in patients undergoing mitral valve surgery. DESIGN: This was a retrospective database review. Logistic regression analysis was performed to assess the associations of perioperative factors with blood lactate in the intensive care unit (ICU). SETTING: Tertiary-care teaching hospital. PARTICIPANTS: The study comprised 917 patients undergoing mitral valve surgery. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The majority of patients (71.8%) had elevated blood lactate ≥2 mmol/L on ICU admission; however, within 24 hours, 85.1% of all patients had normal lactate values. Overall 30-day mortality was 2.29% (n = 21). The combination of lactate ≥7 mmol/L on ICU admission and a persistent elevated blood lactate level 24 hours after ICU admission provides an excellent prediction of 30-day mortality (C statistic = 0.85). However, even a significantly elevated lactate level on ICU admission was well-tolerated in the majority of patients as long as lactate values normalized within 24 hours. Male sex, longer cardiopulmonary bypass time, blood transfusion in the ICU, and an elevated blood lactate level on ICU admission and 12 hours after ICU admission all were independent risk factors of clearance failure. CONCLUSIONS: An elevated blood lactate level is common after mitral valve surgery and is well-tolerated in the majority of patients. Adding lactate clearance improved the predictive value of the blood lactate level.

The Incidence, Risk Factors, and Outcomes of Hyperlactatemia after Heart Transplantation.

Hyperlactatemia (HL) is associated with tissue hypoperfusion during cardiac surgery, which results in postoperative morbidity and mortality among patients undergoing cardiopulmonary bypass surgery. The aim of this study was to determine the incidence, risk factors, and outcome of HL after heart transplantation (HTx) in one of the largest Japanese single-center cohorts. We retrospectively studied the lactate levels in 49 patients who underwent HTx at the University of Tokyo Hospital from August 1, 2010 to November 30, 2015. All of the patients were over 20 years of age. Arterial blood samples were analyzed during the operation and until 24 hours after surgery. Twenty-nine patients (59.2%) had HL after intensive-care unit admission. At 24 hours after surgery, the lactate levels of all patients had recovered to the normal range. A multivariate analysis showed that the total ischemic time of the donor heart (odds ratio [OR], 1.0176; 95% confidence interval [CI], 1.0004-1.0375; P = 0.0444) and the duration of preoperative left ventricular assist device (LVAD) support (OR, 0.9977; 95% CI, 0.9952-0.9997; P = 0.0218) were risk factors for HL. Pulmonary complications were noted in 24.1% of the patients with high lactate values but in none of the patients without HL (P = 0.0182); however, there were no cases of hospital death, and the length of hospital stay did not differ to a statistically significant degree between HL groups (P = 0.719). Although HL after HTx was common, it appeared to be transient and benign. Donor heart ischemia and the duration of preoperative LVAD support were associated with HL after transplantation.

Peripheral venoarterial extracorporeal membrane oxygenation for severe hyperlactataemia after cardiac surgery: a pilot study.

BACKGROUND: Severe hyperlactataemia in patients after cardiac surgery is associated with poor prognosis and implies possible splanchnic hypoperfusion. Peripheral venoarterial extracorporeal membrane oxygenation (splanchnic ECMO) may be more effective at reducing lactic acidosis for these patients. OBJECTIVE: To investigate whether splanchnic ECMO attenuates hyperlactataemia and liver enzyme release in these patients, despite them having a cardiac index > 2 L/min/m2 and a mixed venous oxygen saturation > 55%. DESIGN AND PARTICIPANTS: Retrospective matched case- control study of patients treated with splanchnic ECMO for hyperlactataemia. Seven patients who had had cardiac surgery were treated with splanchnic ECMO compared with seven matched control patients. RESULTS: We observed a mean decrease in lactate levels from 9.9 mmol/L (SD, 2.9 mmol/L) to 1.4 mmol/L (SD, 0.6 mmol/L) in patients receiving 48 hours of splanchnic ECMO, compared with a mean of 10.4 mmol/L (SD, 2.8 mmol/L) to 4.4 mmol/L (SD, 5 mmol/L) during 48 hours in control patients (P < 0.0001). Normalisation of lactate levels (to < 2 mmol/L) was achieved within a mean of 16.3 hours (SD, 14.6 hours) with splanchnic ECMO, compared with 38.3 hours (SD, 23.8 hours) in the control group (P = 0.029). The median increase in alanine aminotransferase level with splanchnic ECMO was 68% (range, -84% to 2015%) compared with 158% (range: 0%-6024%) (not significant) in control patients. CONCLUSION: In a selected cohort of patients who had had cardiac surgery with severe post-operative hyperlactataemia, despite an acceptable cardiac index and a mixed venous oxygen saturation, splanchnic ECMO appeared to reduce overall lactate levels and time to normalisation of lactataemia.

Hyperlactatemia in ICU patients: Incidence, causes and associated mortality.

PURPOSE: To describe the incidence, causes and associated mortality of hyperlactatemia in critically ill patients and to evaluate the association between lactate clearance and in-hospital survival. METHODS: Retrospective cohort study of patients with hyperlactatemia admitted to the ICU. Hyperlactatemia was defined as a blood lactate concentration ≥5mmol/L and high-grade hyperlactatemia a lactate level ≥10mmol/L. Lactate clearance was calculated as the percentage of decrease in lactate concentration from the peak value. RESULTS: Of 10,123 patients, 1373 (13.6%) had lactate concentration ≥5mmol/L, and 434(31.6%) of them had ≥10mmol/L. The most common causes of hyperlactatemia were sepsis/septic shock and post-cardiac surgery. An association was found between lactate concentration and in-hospital mortality (p<0.001). The area under the receiver-operating-characteristics (ROC) of lactate concentration and the optimal cut off to predict mortality were 0.72 (0.70-0.75) and 8.6mmol/L, respectively. ROC analysis for lactate clearance to predict in-hospital survival showed that the best area under the curve was obtained at 12h: 0.67 (95% confidence interval 0.59-0.75). CONCLUSIONS: Hyperlactatemia was common and associated with a high mortality in critically ill patients. Lactate clearance had limited utility for predicting in-hospital survival.

Hyperlactatemia and Cardiac Surgery.

The normal blood lactate level is 0-2 mmol/L, and a value above 3-5 mmol/L is variably used to define hyperlactatemia. In cardiac surgical patients, hyperlactatemia can arise from both hypoxic and non-hypoxic mechanisms. The major non-hypoxic mechanism is likely stress-induced accelerated aerobic metabolism, in which elevated lactate results from a mass effect on the lactate/pyruvate equilibrium. The lactate/pyruvate ratio is normal (<20) in this circumstance. Hyperlactatemia can also result from impaired global or regional oxygen delivery, in which case the lactate/pyruvate ratio is typically elevated (>20). Lactate is a strong anion that is virtually fully dissociated at physiological pH. As such, increased lactate concentration reduces the strong ion difference and exerts an acidifying effect on the blood. Hyperlactatemia in cardiac surgery patients has been categorized as either early or late onset. Early-onset hyperlactatemia is that which develops in the operating room or very early following intensive care unit (ICU) admission. Early-onset hyperlactatemia is strongly associated with adverse outcome and probably arises as a consequence of both hypoxic (e.g., microcirculatory shock) and non-hypoxic (accelerated aerobic metabolism) mechanisms. By contrast, late-onset hyperlactatemia is a benign, self-limiting condition that typically arises within 6-12 hours of ICU admission and spontaneously resolves within 24 hours. Late onset hyperlactatemia occurs in the absence of any evidence of global or regional tissue hypoxia. The mechanism of late onset hyperlactatemia is not understood. Hyperlactatemia is a common accompaniment to treatment with ß2-agonists such as epinephrine. Epinephrine-induced hyperlactatemia is thought to be due to accelerated aerobic metabolism and requires no specific intervention. Irrespective of the cause, the presence of hyperlactatemia should trigger a search for remedial causes of impaired tissue oxygenation, bearing in mind that normal-or even supranormal-indices of global oxygen delivery may exist despite regional tissue hypoperfusion.

Impact of Epinephrine Contained in Local Anesthetic Solution on Serum Lactate Level During Orthognathic Surgery.

PURPOSE: There have been many discussions of a relation between endogenous and exogenous epinephrine and hyperlactatemia. This study aimed to identify the impact of epinephrine contained in a local anesthetic solution on serum lactate levels in patients who underwent orthognathic surgery. MATERIALS AND METHODS: This study was a retrospective record review of cases of maxillary and mandibular osteotomy at the Tokyo University Hospital (Tokyo, Japan) from January 2006 through December 2014. One hundred ninety-three patients were enrolled in this study. RESULTS: The maximum intraoperative serum lactate level was 22.3 ± 14.7 mg/dL. Of 193 patients, 91 showed an intraoperative serum lactate level that was higher than the normal maximum of 19.8 mg/dL (2.2 mmol/L), and 16 of these had a level that was at least 40 mg/dL (≥4.49 mmol/L). Multiple logistic regression analysis showed 2 factors that could increase the serum lactate level: the amount of epinephrine contained in the local anesthetic solution injected into the oral cavity (odds ratio [OR] = 1.014; 95% confidence interval [CI], 1.006-1.022; P = .0001) and the absence of intraoperative treatment with propranolol (OR, 0.105; 95% CI, 0.019-0.434; P = .0013). Patients with severe serum lactate concentrations (ie, ≥40 mg/dL [≥4.49 mmol/L]) had slight metabolic acidosis. All patients survived 90 days. The number of postoperative hospitalization days for patients with severe serum lactate concentrations was 12.8 ± 2.6 days and that for patients without severe serum lactate concentration was 16.0 ± 8.6 days. CONCLUSION: Increases in intraoperative serum lactate levels during orthognathic surgery are associated, at least in part, with increased aerobic glycolysis because of ß2-adrenergic signaling. Lactate increase caused by epinephrine contained in a local anesthetic solution does not result in a poor postoperative outcome.

Hyperlactatemia in patients undergoing adult cardiac surgery under cardiopulmonary bypass: Causative factors and its effect on surgical outcome.

OBJECTIVES OF THE STUDY: To identify the factors causing high lactate levels in patients undergoing cardiac surgery under cardiopulmonary bypass (CPB) and to assess the association between high blood lactate levels and postoperative morbidity and mortality. METHODS: A retrospective observational study including 370 patients who underwent cardiac surgeries under cardiopulmonary bypass. The patients were divided into 2 groups based on serum lactate levels; those with serum lactate levels greater than or equal to 4 mmol/L considered as hyperlactatemia and those with serum lactate levels less than 4 mmol/L. Blood lactate samples were collected intraoperatively and postoperatively in the ICU. Preoperative and intraoperative risk factors for hyperlactatemia were identified using the highest intraoperative value of lactate. The postoperative morbidity and mortality associated with hyperlactatemia was studied using the overall (intraoperative and postoperative values) peak lactate levels. Preoperative clinical data, perioperative events and postoperative morbidity and mortality were recorded. RESULTS: Intraoperative peak blood lactate levels of 4.0 mmol/L or more were present in 158 patients (42.7%). Females had higher peak intra operative lactate levels (P = 0.011). There was significant correlation between CPB time (Pearson correlation coefficient r = 0.024; P = 0.003) and aortic cross clamp time (r = 0.02, P = 0.007) with peak intraoperative blood lactate levels. Patients with hyperlactatemia had significantly higher rate of postoperative morbidity like atrial fibrillation (19.9% vs. 5.3%; P = 0.004), prolonged requirement of inotropes (34% vs. 11.8%; P = 0.001), longer stay in the ICU (P = 0.013) and hospital (P = 0.001). CONCLUSIONS: Hyperlactatemia had significant association with post-operative morbidity. Detection of hyperlactatemia in the perioperative period should be considered as an indicator of inadequate tissue oxygen delivery and must be aggressively corrected.