Persistent occult hypoperfusion is associated with a significant increase in infection rate and mortality in major trauma patients

Real-Time Measurements of Oral Mucosal Carbon Dioxide (POMCO2) Reveals an Inverse Correlation With Blood Pressure in a Porcine Model of Coagulopathic Junctional Hemorrhage

INTRODUCTION

Shock states that occur during, for example, profound hemorrhage can cause global tissue hypoperfusion leading to organ failure. There is an unmet need for a reliable marker of tissue perfusion during hemorrhage that can be followed longitudinally. Herein, we investigated whether longitudinal POMCO2 tracks changes in hemodynamics in a swine model of coagulopathic uncontrolled junctional hemorrhage.

MATERIALS AND METHODS

Female Yorkshire-crossbreed swine (n = 7, 68.1 ± 0.7 kg) were anesthetized and instrumented for continuous measurement of mean arterial pressure (MAP). Coagulopathy was induced by the exchange of 50 to 60% of blood volume with 6% Hetastarch over 30 minutes to target a hematocrit of <15%. A 4.5-mm arteriotomy was made in the right common femoral artery with 30 seconds of free bleeding. POMCO2 was continuously measured from baseline through hemodilution, hemorrhage, and a subsequent 3-h intensive care unit period. Rotational thromboelastometry and blood gases were measured.

RESULTS

POMCO2 and MAP showed no significant changes during the hemodilution phase of the experiment, which produced coagulopathy evidenced by prolonged clot formation times. However, POMCO2 increased because of the uncontrolled hemorrhage by 11.3 ± 3.1 mmHg and was inversely correlated with the drop (17.9 ± 5.9 mmHg) in MAP (Y = -0.4122*X + 2.649, P = .02, r2 = 0.686). In contrast, lactate did not significantly correlate with the changes in MAP (P = .35) or POMCO2 (P = .37).

CONCLUSIONS

Despite the logical appeal of measuring noninvasive tissue CO2 measurement as a surrogate for gastrointestinal perfusion, prior studies have only reported snapshots of this readout. The present investigation shows real-time longitudinal measurement of POMCO2 to confirm that MAP inversely correlates to POMCO2 in the face of coagulopathy. The simplicity of measuring POMCO2 in real time can provide an additional practical option for military or civilian medics to monitor trends in hypoperfusion during hemorrhagic shock.

Occult hypoperfusion and changes of systemic lipid levels after severe trauma: an analysis in a standardized porcine polytrauma model

BACKGROUND

Occult hypoperfusion describes the absence of sufficient microcirculation despite normal vital signs. It is known to be associated with prolonged elevation of serum lactate and later complications in severely injured patients. We hypothesized that changes in circulating lipids are related to responsiveness to resuscitation. The purpose of this study is investigating the relation between responsiveness to resuscitation and lipidomic course after poly trauma.

METHODS

Twenty-five male pigs were exposed a combined injury of blunt chest trauma, liver laceration, controlled haemorrhagic shock, and femoral shaft fracture. After 1 h, animals received resuscitation and fracture stabilization. Venous blood was taken regularly and 233 specific lipids were analysed. Animals were divided into two groups based on serum lactate level at the end point as an indicator of responsiveness to resuscitation (<2 mmol/L: responder group (R group), ≧2 mmol/L: occult hypoperfusion group (OH group)).

RESULTS

Eighteen animals met criteria for the R group, four animals for the OH group, and three animals died. Acylcarnitines showed a significant increase at 1 h compared to baseline in both groups. Six lipid subgroups showed a significant increase only in R group at 2 h. There was no significant change at other time points.

CONCLUSIONS

Six lipid groups increased significantly only in the R group at 2 h, which may support the idea that they could serve as potential biomarkers to help us to detect the presence of occult hypoperfusion and insufficient resuscitation. We feel that further study is required to confirm the role and mechanism of lipid changes after trauma.

Impact of Intra-Operative Shock and Resuscitation on Surgical Site Infections After Trauma Laparotomy

Background: Patients undergoing trauma laparotomy experience high rates of surgical site infection (SSI). Although intra-operative shock is a likely contributor to SSI risk, little is known about the relation between shock, intra-operative restoration of physiologic normalcy, and SSI development. Patients and Methods: A retrospective review of trauma patients who underwent emergent definitive laparotomy was performed. Using shock index and base excess at the beginning and end of laparotomy, patients were classified as normal, persistent shock, resuscitated, or new shock. Univariable and multivariable analyses were performed to identify predictors of organ/space SSI, superficial/deep SSI, and any SSI. Results: Of 1,191 included patients, 600 (50%) were categorized as no shock, 248 (21%) as resuscitated, 109 (9%) as new shock, and 236 (20%) as persistent shock, with incidence of any SSI as 51 (9%), 28 (11%), 26 (24%), and 32 (14%), respectively. These rates were similar in organ/space and superficial/deep SSIs. On multivariable analysis, resuscitated, new shock, and persistent shock were associated with increased odds of organ/space SSI (odds ratio [OR], 2.2; 95% confidence interval [CI], 1.3-3.5; p < 0.001) and any SSI (OR, 2.0; 95% CI, 1.4-3.2; p < 0.001), but no increased risk of superficial/deep SSI (OR, 1.4; 95% CI, 0.8-2.6; p = 0.331). Conclusions: Although the trajectory of physiologic status influenced SSI, the presence of shock at any time during trauma laparotomy, regardless of restoration of physiologic normalcy, was associated with increased odds of SSI. Further investigation is warranted to determine the relation between peri-operative shock and SSI in trauma patients.

Value, time and outcomes of elevated lactate levels in adult patients on extracorporeal membrane oxygenation

INTRODUCTION

Lactate levels have been recognized as a reliable tool for monitoring critically ill patients requiring venoarterial extracorporeal membrane oxygenation (VA ECMO) or venovenous extracorporeal membrane oxygenation (VV ECMO) but the reasons behind the overproduction of lactate are different and the influance for survival remains controversial. We analyzed the lactate values and lactate clearance in adult patients in these two forms of extracorporeal support.

METHODS

Patient demographics, ECMO duration, 30-day mortality, lactate values and lactate clearance at 24, 48 and 72 h from ECMO initiation of patients supported with VV and VA ECMO at Silesian Centre for Heart Deasese, between January 2011 and April 2020 were retrospectively analyzed. The changes in lactate levels were analyzed using the non-parametric U Mann-Whitney tests and Chi-square test. The ROC curves were draw and the area under the curve was calculated.

RESULTS

The study comprised 91 adult patients, Mortality in the first 30 days from initiation of VV and VA ECMO was 39% and 66%, respectively. Lactate levels were significantly higher in non-survivors that received VV and VA ECMO (p < .001), while lactate clearance was similar (p = .256 and p = 1.000, respectively). Survival curves for patients with elevated (>2.0 mmol/L) vs normal (≤2.0 mmol/L) lactate levels at 72 h were significantly different for VV ECMO (p = .007) and VA ECMO (p = .037) but in both groups of ECMO, lactate levels above 2.0 mmol/L at 72 h from ECMO initiation predicted 30 day-mortality.

CONCLUSION

This results emphasized the importance of lactate levels below 2.0 mmol/L at 72 h from both VV and VA ECMO initiation.

Lactate Clearance as an Early Prognostic Marker of Mortality for Pediatric Trauma

Background While lactate clearance (LC) has already been shown as a prognostic indicator in clinical studies, its certain character needs to be defined in pediatric trauma. This research aimed to evaluate the correlation between early lactate clearance and mortality in pediatric trauma.Patients and methods A retrospective cohort study was conducted in a university hospital. Repeated LC was measured at admission, at the 2nd, 6th, and 12th hours post-admission. The association of lactate clearance with mortality was analyzed and using receiver operating characteristic (ROC) to determine the threshold levels of lactate clearance and also logistic regression analysis was performed to determine whether LC was an independent risk factor.Results Seventy-eight patients were included and overall mortality was 13%. LC values of the non-survivors was significantly lower than survivors for LC0-2 h (28.60±14.26 vs 4.64±15.90), LC0-6 h (46.63±15.23 vs 3.33±18.07), LC0-12 h (56.97±15.53 vs 4.82±22.59) (p:<0.001, p:<0.001 and p:<0.001, respectively). Areas under the curve of lactate clearance at the 2nd, 6th, and 12th hours after therapy start were a significant predictor for mortality (p:<0.001, p:<0.001, and p:<0.001, respectively). Threshold values of LC were 12.9, 19.5 and 29.3%, respectively.Conclusion Lactate clearance was a beneficial tool to estimate outcomes of pediatric trauma. Poor lactate clearance was a significant marker for poor prognosis.

Markers of tissue perfusion and their relation to mortality in dogs with blunt trauma

OBJECTIVE

To evaluate admission Animal Trauma Triage (ATT) score, shock index (SI), and markers of perfusion, including base excess (BE), plasma lactate, and lactate clearance in dogs with blunt trauma.

DESIGN

Prospective observational clinical study from 2013 to 2015.

SETTING

Private veterinary referral and emergency center.

ANIMALS

Forty-four client-owned dogs hospitalized following blunt trauma.

INTERVENTION

Within 1 hour of presentation and prior to fluid administration an initial hematocrit, total plasma protein, blood glucose, plasma lactate, blood gas, and electrolytes were obtained for analysis. Plasma lactate concentrations were also measured 4 and 8 hours following initial measurement, and a 4-hour lactate clearance was calculated if patients had an increased admission plasma lactate. ATT score and SI were calculated for each patient based on admission data. Outcome was defined as survival to hospital discharge.

MEASUREMENTS AND MAIN RESULTS

Twenty-nine dogs survived, 14 were euthanized, and 1 died. Nonsurviving dogs had a lower mean pH (7.28 ± 0.03 vs 7.36 ± 0.01, P = 0.006), lower median HCO₃ (15.7 vs 18.8 mmol/L, P = 0.004), lower median admission BE (-11.0 vs -7.0 mmol/L, P = 0.004), and higher median admission lactate (3.1 vs 2.4 mmol/L, P = 0.036) than those who survived. Median ATT was significantly higher in nonsurvivors (5 vsF 2, P < 0.001). The SI was not significantly different between survivors and nonsurvivors (P = 0.41). There was no difference in median 4-hour lactate (P = 0.34), median 8-hour lactate (P = 0.19), or 4-hour lactate clearance (P = 0.83) in survivors compared to nonsurvivors. No other statistically significant differences were noted between groups.

CONCLUSION

Dogs hospitalized following blunt trauma with a lower admission pH, HCO₃ , and BE and a higher admission plasma lactate were less likely to survive to hospital discharge. Median ATT score was also significantly higher in nonsurvivors. Although lactate clearance was not predictive of survival, the sample size was small, and additional studies with a larger study population are warranted.

Evaluation of caudal vena cava size using computed tomography in dogs under general anesthesia

This study investigated the association between caudal vena cava (CVC) size and circulatory dynamics in dogs using computed tomography (CT) under general anesthesia. The subjects were 104 dogs who had undergone CT under general anesthesia in the past. The ratio of short diameter of the CVC to aortic diameter (CVC_S/Ao) and the ratio of long to short diameter of the CVC (CVC_L/CVC_S) in the thorax and abdomen, respectively, were calculated using factors such as mean blood pressure (MBP), shock index (SI), anemia, hypoproteinemia, presence of intra-abdominal mass, and cardiac disease. There was a significant but negligible negative correlation between CVC_S/Ao and MBP. In contrast, no significant correlation was found between CVC size and SI. The low MBP group had significantly higher CVC_S/Ao of the thorax than the normal MBP group. The group with intra-abdominal mass had significantly lower CVC_S/Ao of the abdomen than the group without intra-abdominal mass. The group with cardiac disease had significantly lower CVC_L/CVC_S of the thorax than the group without cardiac disease. In multiple regression analysis, low MBP, cardiac disease, intra-abdominal mass, and anemia were significant factors for CVC_S/Ao of the thorax, CVC_L/CVC_S of the thorax, CVC_S/Ao of the abdomen, and CVC_L/CVC_S of the abdomen, respectively. In conclusion, CVC size assessment using CT in dogs under general anesthesia is influenced by various factors.

LONGITUDINAL ANALYSIS OF TRANSCRIPTOMIC SUBTYPES IN TRAUMA PATIENTS

ABSTRACT

Objective: We previously identified two transcriptomic subtypes (Signature Groups: SG1 vs. SG2) in trauma patients at 12 hours postinjury, with SG1 associated with worse outcomes. In this study, we aimed to further characterize the changes in SG subtype categorization of trauma patients over time after injury and define the corresponding association with outcomes based on the timing of the subtype designation. Methods and Results: This study was a secondary analysis of published data of whole-blood leukocyte transcriptomics, a longitudinal data from 167 severe blunt trauma patients. We assigned trauma patients to SG1 or SG2 subtype for time points between 12 hours and 28 days, inclusive, postinjury and characterized their longitudinal outcomes. SG1 assignment, regardless of time point, was associated consistently with slower recovery. Further analysis revealed that additional prognostic information could be obtained by assessing SG subtype at both 12 hours and 1 day. Conclusions: This study provides a proof of concept that immune status can worsen after admission and highlights the benefit of longitudinally monitoring SG subtypes in trauma patients.

Effects of Occult Hypoperfusion on Local Circulation and Inflammation - An Analysis in a Standardized Polytrauma Model

Introduction

Occult hypoperfusion (OH) is defined as persistent lactic acidosis despite normalization of vital parameters following trauma. The aim of this study was to analyze the association of occult hypoperfusion with local circulation and inflammation of injured soft tissue in a porcine polytrauma model.

Methods

This experimental study was performed with male landrace pigs who suffered a standardized polytrauma, including a femoral fracture, blunt chest trauma, liver laceration and a mean arterial pressure (MAP) controlled hemorrhagic shock. One hour after induction of trauma, the animals were resuscitated with retrograde femoral nailing, liver packing and volume replacement. Animals were stratified into Group Norm (normalizing lactate levels after resuscitation) and Group occult hypoperfusion (OH) (persistent lactate levels above 2 mmol/l with normalizing vital parameters after resuscitation). Local circulation (oxygen saturation, hemoglobin amount, blood flow) was measured with optical sensors at the subcutaneous soft tissue at the fractured extremity as well as at the stomach and colon. Local inflammatory parameters [interleukin (IL) 6, 8, 10, and heat shock protein (HSP)] were analyzed in the subcutaneous tissue of the fractured extremity.

Results

Group Norm (n = 19) and Group OH (n = 5) were comparable in baseline vital and laboratory parameters. The shock severity and total amount of blood loss were comparable among Group Norm and Group OH. Following resuscitation Group OH had significantly lower local relative hemoglobin amount at the injured soft tissue of the fractured extremity when compared with Group Norm (39.4, SD 5.3 vs. 63.9, SD 27.6 A.U., p = 0.031). The local oxygenation was significantly lower in Group OH compared to Group Norm (60.4, SD 4.6 vs. 75.8, SD 12.8, p = 0.049). Local IL-6 in the fatty tissue was significantly higher in Group OH (318.3, SD 326.6 [pg/ml]) when compared with Group Norm (73.9,SD 96.3[pg/ml], p = 0.03). The local circulation at the abdominal organs was comparable in both groups.

Conclusion

OH is associated with decreased local circulation and increased local inflammation at the injured soft tissue of the extremity in polytrauma. OH might reflect the severity of local soft tissue injuries, and guide treatment strategies.

Machine Learning Consensus Clustering Approach for Patients with Lactic Acidosis in Intensive Care Units

BACKGROUND

Lactic acidosis is a heterogeneous condition with multiple underlying causes and associated outcomes. The use of multi-dimensional patient data to subtype lactic acidosis can personalize patient care. Machine learning consensus clustering may identify lactic acidosis subgroups with unique clinical profiles and outcomes.

METHODS

We used the Medical Information Mart for Intensive Care III database to abstract electronic medical record data from patients admitted to intensive care units (ICU) in a tertiary care hospital in the United States. We included patients who developed lactic acidosis (defined as serum lactate ≥ 4 mmol/L) within 48 h of ICU admission. We performed consensus clustering analysis based on patient characteristics, comorbidities, vital signs, organ supports, and laboratory data to identify clinically distinct lactic acidosis subgroups. We calculated standardized mean differences to show key subgroup features. We compared outcomes among subgroups.

RESULTS

We identified 1919 patients with lactic acidosis. The algorithm revealed three best unique lactic acidosis subgroups based on patient variables. Cluster 1 (n = 554) was characterized by old age, elective admission to cardiac surgery ICU, vasopressor use, mechanical ventilation use, and higher pH and serum bicarbonate. Cluster 2 (n = 815) was characterized by young age, admission to trauma/surgical ICU with higher blood pressure, lower comorbidity burden, lower severity index, and less vasopressor use. Cluster 3 (n = 550) was characterized by admission to medical ICU, history of liver disease and coagulopathy, acute kidney injury, lower blood pressure, higher comorbidity burden, higher severity index, higher serum lactate, and lower pH and serum bicarbonate. Cluster 3 had the worst outcomes, while cluster 1 had the most favorable outcomes in terms of persistent lactic acidosis and mortality.

CONCLUSIONS

Consensus clustering analysis synthesized the pattern of clinical and laboratory data to reveal clinically distinct lactic acidosis subgroups with different outcomes.

The Effect of Betulin Diphosphate in Wound Dressings of Bacterial Cellulose-ZnO NPs on Platelet Aggregation and the Activity of Oxidoreductases Regulated by NAD(P)+/NAD(P)H-Balance in Burns on Rats

The inhibition of platelet aggregation, and the activity of oxidoreductases and microhemocirculation in a burn wound on the treatment of burns with wound dressings based on bacterial nanocellulose (BC)-zinc oxide nanoparticles (ZnO NPs)-betulin diphosphate (BDP) were studied. The control of the treatment by BC-ZnO NPs-BDP on burned rats by the noninvasive DLF method showed an increase in perfusion and the respiratory component in wavelet spectra, characterizing an improvement in oxygen saturation in the wound. The study on the volunteers' blood found the inhibition of ADP-induced platelet aggregation by 30-90%. Disaggregation depends on the dose under the action of the ionized form of BDP and ZnO NPs-BDP in a phosphate buffer; it was reversible and had two waves. It was shown on rats that the specific activity of LDHreverse and LDHdirect (control-intact animals) on day 21 of treatment increased by 11-38% and 23%, respectively. The LDHreverse/LDHdirect ratio increased at BC-ZnO NPs-BDP treatment, which characterizes efficient NAD+ regeneration. AlDH activity increased significantly in the first 10 days by 70-170%, reflecting the effectiveness of the enzyme and NAD+ in utilizing toxic aldehydes at this stage of burn disease. The activities of GR and G6PDH using NADP(H) were increased with BC-ZnO NPs-BDP treatment.

Dose-dependent association between blood transfusion and nosocomial infections in trauma patients: A secondary analysis of patients from the PAMPer trial

BACKGROUND

The Prehospital Air Medical Plasma (PAMPer) trial demonstrated a survival benefit to trauma patients who received thawed plasma as part of early resuscitation. The objective of our study was to examine the association between blood transfusion and nosocomial infections among trauma patients who participated in the PAMPer trial. We hypothesized that transfusion of blood products will be associated with the development of nosocomial infections in a dose-dependent fashion.

METHODS

We performed a secondary analysis of prospectively collected data of patients in the PAMPer trial with hospital length of stay of at least 3 days. Demographics, injury characteristics, and number of blood products transfused were obtained to evaluate outcomes. Bivariate analysis was performed to identify differences between patients with and without nosocomial infections. Two logistic regression models were created to evaluate the association between nosocomial infections and (1) any transfusion of blood products, and (2) quantity of blood products. Both models were adjusted for age, sex, and Injury Severity Score.

RESULTS

A total of 399 patients were included: age, 46 years (interquartile range, 29-59 years); Injury Severity Score, 22 (interquartile range, 12-29); 73% male; 80% blunt mechanism; and 40 (10%) deaths. Ninety-three (27%) developed nosocomial infections, including pneumonia (n = 67), bloodstream infections (n = 14), catheter-associated urinary tract infection (n = 10), skin and soft tissue infection (n = 8), Clostridium difficile colitis (n = 7), empyema (n = 6), and complicated intra-abdominal infections (n = 3). Nearly 80% (n = 307) of patients received packed red blood cells (PRBCs); 12% received cryoprecipitate, 69% received plasma, and 27% received platelets. Patients who received any PRBCs had more than a twofold increase in nosocomial infections (odds ratio, 2.15; 95% confidence interval, 1.01-4.58; p = 0.047). The number of PRBCs given was also associated with the development of nosocomial infection (odds ratio, 1.10; 95% confidence interval, 1.05-1.16; p < 0.001).

CONCLUSION

Trauma patients in the PAMPer trial who received a transfusion of at least 1 U of PRBCs incurred a twofold increased risk of nosocomial infection, and the risk of infection was dose dependent.

LEVEL OF EVIDENCE

Therapeutic/care management, level IV.

Prediction of blood lactate values in critically ill patients: a retrospective multi-center cohort study

Elevations in initially obtained serum lactate levels are strong predictors of mortality in critically ill patients. Identifying patients whose serum lactate levels are more likely to increase can alert physicians to intensify care and guide them in the frequency of tending the blood test. We investigate whether machine learning models can predict subsequent serum lactate changes. We investigated serum lactate change prediction using the MIMIC-III and eICU-CRD datasets in internal as well as external validation of the eICU cohort on the MIMIC-III cohort. Three subgroups were defined based on the initial lactate levels: (i) normal group (< 2 mmol/L), (ii) mild group (2-4 mmol/L), and (iii) severe group (> 4 mmol/L). Outcomes were defined based on increase or decrease of serum lactate levels between the groups. We also performed sensitivity analysis by defining the outcome as lactate change of > 10% and furthermore investigated the influence of the time interval between subsequent lactate measurements on predictive performance. The LSTM models were able to predict deterioration of serum lactate values of MIMIC-III patients with an AUC of 0.77 (95% CI 0.762-0.771) for the normal group, 0.77 (95% CI 0.768-0.772) for the mild group, and 0.85 (95% CI 0.840-0.851) for the severe group, with only a slightly lower performance in the external validation. The LSTM demonstrated good discrimination of patients who had deterioration in serum lactate levels. Clinical studies are needed to evaluate whether utilization of a clinical decision support tool based on these results could positively impact decision-making and patient outcomes.

Lactate as a mediator of prehospital plasma mortality reduction in hemorrhagic shock

BACKGROUND

Prehospital plasma transfusion in trauma reduces mortality. However, the underlying mechanism remains unclear. Reduction in shock severity may play a role. Lactate correlates with physiologic shock severity and mortality after injury. Our objective was to determine if prehospital plasma reduces lactate and if this contributes to the mortality benefit of plasma.

METHODS

Patients in the Prehospital Air Medical Plasma trial in the upper quartile of injury severity (Injury Severity Score, >30) were included to capture severe shock. Trial patients were randomized to prehospital plasma or standard care resuscitation (crystalloid ± packed red blood cells). Regression determined the associations between admission lactate, 30-day mortality, and plasma while adjusting for demographics, prehospital crystalloid, time, mechanism, and injury characteristics. Causal mediation analysis determined what proportion of the effect of plasma on mortality is mediated by lactate reduction.

RESULTS

A total of 125 patients were included. The plasma group had a lower adjusted admission lactate than standard of care group (coefficient, -1.64; 95% confidence interval [CI], -2.96 to -0.31; p = 0.02). Plasma was associated with lower odds of 30-day mortality (odds ratio [OR], 0.27; 95% CI, 0.08-0.90; p = 0.03). When adding lactate to this model, the effect of plasma on 30-day mortality was no longer significant (OR, 0.36; 95% CI, 0.07-1.88; p = 0.23), while lactate was associated with mortality (OR, 1.74 per 1 mmol/L increase; 95% CI, 1.10-2.73; p = 0.01). Causal mediation demonstrated 35.1% of the total effect of plasma on 30-day mortality was mediated by the reduction in lactate among plasma patients.

CONCLUSION

Prehospital plasma is associated with reduced 30-day mortality and lactate in severely injured patients. More than one third of the effect of plasma on mortality is mediated by a reduction in lactate. Thus, reducing the severity of hemorrhagic shock appears to be one mechanism of prehospital plasma benefit. Further study should elucidate other mechanisms and if a dose response exists.

LEVEL OF EVIDENCE

Therapeutic, level II.

Predicting the need for blood transfusion requirement in postpartum hemorrhage

OBJECTIVE

We aimed to assess the role of lactate and hemoglobin levels as predictors for the need for blood transfusion in post-partum hemorrhage (PPH).

METHODS

A retrospective cohort study of women with PPH in a single university-affiliated tertiary medical center between August 2018 and June 2020. PPH was defined as an estimated excessive blood loss (of more than 500 ml following vaginal delivery and 1000 ml following a cesarean delivery) requiring at least one uterotonic drug and fluid resuscitation. Women were stratified by the need of requiring blood transfusion due to hemorrhage. The criteria for blood transfusion were: (1) clinically severe uncontrollable ongoing hemorrhage; (2) symptomatic anemia (maternal tachycardia >110 beats per minute, dizziness, syncope or presyncope) in the presence of Hb 7-8 g/dL^; or (3) postpartum Hb level < 7 g/dL regardless of maternal symptoms or signs of anemia. Demographic, labor characteristics as well as laboratory data were collected. For all women the Shock Index (SI: heart rate divided by systolic blood pressure) was calculated. Women without available data on immediate (more than 15 min from the bleeding initiation) hemoglobin (Hb) level and lactate concentrations were excluded.

RESULTS

Overall, out of 22,241 deliveries during the study, 94 women were included, of them 26 (23.4%) required blood transfusion. The antepartum Hb level was lower in the transfused group (11.7 ± vs 12.4 ± 1.0 re/dL, p = .01). No significant differences were found in demographic and labor characteristics. In multivariate logistic regression analysis, a lower immediate postpartum Hb and a higher SI higher were associated with blood transfusion requirement (adjusted odds ratio (aOR) 3.45 [CI] 1.82-7.69, p < .001] and aOR 1.25 [CI 1.03-1.55, p = .03], respectively). The combination of SI, immediate postpartum Hb and lactate concentration provided the best integration, with an area under the curve of 0.86, sensitivity 92.65%, specificity 61.54%, positive and negative predictive values of 86.3% and 76.2%, respectively.

CONCLUSION

The combination of SI, immediate postpartum Hb and lactate levels is a good predictor for the need of blood requirement in PPH.

The Flatness Index of Inferior Vena Cava can be an Accurate Predictor for Hypovolemia in Multi-Trauma Patients

INTRODUCTION

Shock is the leading cause of death in multi-trauma patients and must be detected at an early stage to improve prognosis. Many parameters are used to predict clinical condition and outcome in trauma. Computed tomography (CT) signs of hypovolemic shock in trauma patients are not clear yet, requiring further research. The flatness index of inferior vena cava (IVC) is a helpful method for this purpose.

METHODS

This is a prospective, cross-sectional study which included adult multi-trauma patients (>18 years) who were admitted to the emergency department (ED) and underwent a thoraco-abdominal CT from 2017 through 2018. The main objective of this study was to investigate whether the flatness index of IVC can be used to determine the hypovolemic shock at an early stage in multi-trauma patients, and to establish its relations with shock parameters. The patients' demographic features, trauma mechanisms, vitals, laboratory values, shock parameters, and clinical outcome within 24 hours of admission were recorded.

RESULTS

Total of 327 (229 males with an average age of 40.9 [SD = 7.93]) patients were included in the study. There was no significant difference in the flatness index of IVC within genders (P = .134) and trauma mechanisms (P = .701); however, the flatness index of IVC was significantly higher in hypotensive (systolic blood pressure [SBP] ≤90 mmHg and/or diastolic blood pressure [DBP] ≤60 mmHg; P = .015 and P = .019), tachycardic (P = .049), and hypoxic (SpO2 ≤%94; P <.001) patients. The flatness index of IVC was also higher in patients with lactate ≥ 2mmol/l (P = .043) and patients with Class III hemorrhage (P = .003). A positive correlation was determined between lactate level and the flatness index of IVC; a negative correlation was found between Glasgow Coma Scale (GCS) and Revised Trauma Score (RTS) with the flatness index of IVC (for each of them, P <.05).

CONCLUSION

The flatness index of IVC may be a useful method to determine the hypovolemic shock at an early stage in multi-trauma patients.

Prospective evaluation of plasma lactate parameters for prognosticating dogs with shock

OBJECTIVE

To determine whether admission venous plasma lactate concentration, serially calculated lactate variables, or the Acute Patient Physiologic and Laboratory Evaluation (APPLE_fast ) score could discriminate hospital survivors from non-survivors in dogs presenting to the emergency department with clinical signs of shock.

DESIGN

Prospective case series performed over a 24-month period.

SETTING

Large urban private teaching hospital.

ANIMALS

Seventy-one dogs admitted to the ICU with initial peripheral venous plasma lactate concentration > 2.5 mmol/L and clinical and hemodynamic parameters consistent with shock.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Heart rate, systolic blood pressure, temperature, initial venous plasma lactate, and APPLE_fast score were recorded at admission. Lactate concentrations were serially recorded at predefined time points and used to calculate lactate variables, including lactime (time lactate > 2.5 mmol/L), lactate clearance ([lactate_initial - lactate_delayed ]/ lactate_initial × 100), and LAC_AREA (area under the lactate concentration versus time curve). Primary outcome was survival to discharge. Overall survival rate was 61%. Admission plasma lactate did not differ between groups (P = 0.28). Lactime was shorter in survivors vs non-survivors (P = 0.03). Lactate clearance at hours (h) 1, 4, 10, and 16 was greater in survivors vs non-survivors (P < 0.05). Final plasma lactate clearance differed between groups (P < 0.05). LAC_AREA at time intervals 1 to 4 hours, 4 to 10 hours, 10 to 16 hours, and 16 to 24 hours was larger in non-survivors vs survivors (P < 0.05). Total LAC_AREA did not differ between groups (P = 0.51). Admission APPLE_fast was not different between survivors and non-survivors (P = 0.16).

CONCLUSIONS

While neither single APPLE_fast nor admission plasma lactate concentration could discriminate between hospital survivors and non-survivors, measures of lactate clearance can prognosticate survival in dogs with shock.

Mitochondrial lactate metabolism: history and implications for exercise and disease

Mitochondrial structures were probably observed microscopically in the 1840s, but the idea of oxidative phosphorylation (OXPHOS) within mitochondria did not appear until the 1930s. The foundation for research into energetics arose from Meyerhof's experiments on oxidation of lactate in isolated muscles recovering from electrical contractions in an O2 atmosphere. Today, we know that mitochondria are actually reticula and that the energy released from electron pairs being passed along the electron transport chain from NADH to O2 generates a membrane potential and pH gradient of protons that can enter the molecular machine of ATP synthase to resynthesize ATP. Lactate stands at the crossroads of glycolytic and oxidative energy metabolism. Based on reported research and our own modelling in silico, we contend that lactate is not directly oxidized in the mitochondrial matrix. Instead, the interim glycolytic products (pyruvate and NADH) are held in cytosolic equilibrium with the products of the lactate dehydrogenase (LDH) reaction and the intermediates of the malate-aspartate and glycerol 3-phosphate shuttles. This equilibrium supplies the glycolytic products to the mitochondrial matrix for OXPHOS. LDH in the mitochondrial matrix is not compatible with the cytoplasmic/matrix redox gradient; its presence would drain matrix reducing power and substantially dissipate the proton motive force. OXPHOS requires O2 as the final electron acceptor, but O2 supply is sufficient in most situations, including exercise and often acute illness. Recent studies suggest that atmospheric normoxia may constitute a cellular hyperoxia in mitochondrial disease. As research proceeds appropriate oxygenation levels should be carefully considered.

Fracture fixation in the polytrauma patient: Markers that matter

Timing and type of fracture fixation in the multiply-injured trauma patient have been important and controversial topics. Ideal care for these patients come from providers who communicate well with one another in a team fashion and view the whole person, rather than focusing on injury to individual systems. This group encompasses a wide range of musculoskeletal and other injuries, further complicated by the broad spectrum of patients, with variability in age, medical and social comorbidities, all of which may have profound impact upon outcomes. The concept of Early Total Care arose from the realization that early definitive fixation of femur fractures provided pulmonary and systemic benefits to most patients. However, insufficient assessment and understanding of the physiological status of polytraumatized patients at the time of major orthopaedic procedures, potentially with inclusion of multiple other procedures in the same setting resulted in more morbidity, swinging the pendulum of care toward initial Damage Control Orthopaedics to minimize surgical insult. More recently, iterative assessment of response to resuscitation using Early Appropriate Care guidelines, suggests definitive fixation of most axial and femoral injuries within 36 h after injury appears safe in resuscitated patients, as measured by improvement of acidosis.

The Association of Perioperative Serum Lactate Levels with Postoperative Delirium in Elderly Trauma Patients

Background

Several studies have shown the utility of lactate level as a predictor of early outcomes in trauma patients. We conducted this study to evaluate the association of perioperative serum lactate levels with postoperative delirium (POD) in elderly trauma patients.

Materials and Methods

This study included 466 elderly trauma patients with measurements of serum lactate levels on admission and 1 h after surgery. The associations of POD with serum lactate levels (on admission and 1 h after surgery) and lactate clearance were analyzed using Kendall's correlation. Perioperative serum lactate levels and lactate clearance as predictors of POD were evaluated using univariate and multivariable analyses.

Results

The incidence of POD in the present study was 38.1%. Serum lactate levels on admission and at 1 h after surgery were significantly higher in major trauma than in minor trauma. In univariate analysis of perioperative serum lactate levels and lactate clearance as predictors of POD, the odds ratio (OR) for serum lactate level on admission was 4.19 (P < 0.01, 2.91 < 95% confidence interval (CI) < 6.02) and that 1 h after surgery was 3.83 (P < 0.01, 2.79 < 95% CI < 5.25); however, the OR for serum change of lactate level was 0.99 ((P < 0.09, 0.99 < 95% CI < 1.00). In multivariable analysis for predictors of POD, the OR for serum lactate level on admission was 2.40 (P < 0.09, 0.87 < 95% CI < 6.7), that for serum lactate 1 h after surgery was 2.83 (P=0.01, 1.28 < 95% CI < 6.24), that for ICU admission was 3.01 (P=0.01, 2.09 < 95% CI < 6.03), and that for ISS was 1.47 (P < 0.01, 1.27 < 95% CI < 3.70).

Conclusions

Taking together the results of univariate and multivariable analyses, serum lactate level 1 h after surgery may be used as a prediction model of POD development in elderly trauma patients.

Shock volume: Patient-specific cumulative hypoperfusion predicts organ dysfunction in a prospective cohort of multiply injured patients

BACKGROUND

Multiply injured patients are at risk of developing hemorrhagic shock and organ dysfunction. We determined how cumulative hypoperfusion predicted organ dysfunction by integrating serial Shock Index measurements.

METHODS

In this study, we calculated shock volume (SHVL) which is a patient-specific index that quantifies cumulative hypoperfusion by integrating abnormally elevated Shock Index (heart rate/systolic blood pressure ≥ 0.9) values acutely after injury. Shock volume was calculated at three hours (3 hr), six hours (6 hr), and twenty-four hours (24 hr) after injury. Organ dysfunction was quantified using Marshall Organ Dysfunction Scores averaged from days 2 through 5 after injury (aMODSD2-D5). Logistic regression was used to determine correspondence of 3hrSHVL, 6hrSHVL, and 24hrSHVL to organ dysfunction. We compared correspondence of SHVL to organ dysfunction with traditional indices of shock including the initial base deficit (BD) and the lowest pH measurement made in the first 24 hr after injury (minimum pH).

RESULTS

SHVL at all three time intervals demonstrated higher correspondence to organ dysfunction (R = 0.48 to 0.52) compared to initial BD (R = 0.32) and minimum pH (R = 0.32). Additionally, we compared predictive capabilities of SHVL, initial BD and minimum pH to identify patients at risk of developing high-magnitude organ dysfunction by constructing receiver operator characteristic curves. SHVL at six hours and 24 hours had higher area under the curve compared to initial BD and minimum pH.

CONCLUSION

SHVL is a non-invasive metric that can predict anticipated organ dysfunction and identify patients at risk for high-magnitude organ dysfunction after injury.

LEVEL OF EVIDENCE

Prognostic study, level III.

High incidence of multiresistant bacterial isolates from bloodstream infections in trauma emergency department and intensive care unit in Serbia

We investigated the incidence of bloodstream infections (BSIs) in trauma emergency department (ED) and intensive care unit (ICU), to assess ED- and ICU-related predictors of BSI and to describe the most common bacteria causing BSI and their antimicrobial resistance markers. A prospective study was conducted in two trauma ICUs of the ED of Clinical Center of Serbia. Overall, 62 BSIs were diagnosed in 406 patients, of which 13 were catheter-related BSI (3.0/1,000 CVC-days) and 30 BSIs of unknown origin, while 15% were attributed to ED CVC exposure. Lactate ≥2 mmol/L and SOFA score were independent ED-related predictors of BSI, while CVC in place for >7 days and mechanical ventilation >7 days were significant ICU-related predictors. The most common bacteria recovered were Acinetobacter spp., Klebsiella spp., and Pseudomonas aeruginosa. All Staphylococcus aureus and coagulase-negative staphylococci isolates were methicillin-resistant, whereas 66% of Enterococcus spp. were vancomycin-resistant. All isolates of Enterobacteriaceae were resistant to third-generation cephalosporins, whereas 87.5% of P. aeruginosa and 95.8% of Acinetobacter spp. isolates were resistant to carbapenems. ED BSI contributes substantially to overall ICU incidence of BSI. Lactate level and SOFA score can help to identify patients with higher risk of developing BSI. Better overall and CVC-specific control measures in patients with trauma are needed.

Utility of admission lactate concentration, lactate variables, and shock index in outcome assessment in dogs diagnosed with shock

OBJECTIVE

To determine whether admission venous plasma lactate concentration, calculated lactate variables, or shock index (SI) could discriminate hospital survivors from nonsurvivors in dogs admitted with shock.

DESIGN

Prospective investigation performed over a 19-month period.

SETTING

Large urban private teaching hospital.

ANIMALS

Twenty-three dogs consecutively admitted to the ICU from January 2008 to July 2009 with initial peripheral venous plasma lactate concentration >2 mmol/L (18.0 mg/dL) and clinical and hemodynamic parameters consistent with shock.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Heart rate, systolic blood pressure, and venous plasma lactate concentrations were serially recorded at predefined time points and used to calculate SI (SI = heart rate/systolic blood pressure) and lactate variables, including lactime (time lactate > 2.0 mmol/L), lactate clearance ([lactate_initial - lactate_delayed ]/lactate_initial × 100), and LAC_AREA (area under the lactate concentration versus time curve). Primary outcome was survival to discharge. Overall survival rate was 61%. Admission venous plasma lactate concentration did not differ between groups (P = 0.2). Lactime was shorter in survivors versus nonsurvivors (P = 0.02). Lactate clearance at 1, 10, 16, 24, and 36 hours, and final lactate clearance were greater in survivors versus nonsurvivors (P < 0.05). LAC_AREA at time intervals 0-1, 1-4, 4-10, 10-16, 16-24, 24-30, and 30-36 hours was larger in nonsurvivors versus survivors (P < 0.05). Total LAC_AREA did not differ between groups (P = 0.09). Admission SI and time to normalize SI (SI < 0.9) were not different between survivors and nonsurvivors (P > 0.05).

CONCLUSIONS

While admission venous plasma lactate concentration could not discriminate between hospital survivors and nonsurvivors, lactate variables showed clinical utility to predict outcome in dogs with shock. Further studies are needed to determine SI reference ranges and optimal SI cut-off values to improve its prognostic ability in sick dogs.

Lactate and cancer: a "lactatic" perspective on spinal tumor metabolism (part 1)

Spine tumors are among the most difficult tumors to treat given their proximity to the spinal cord. Despite advances in adjuvant therapies, surgery remains a critical component of treatment, both in primary tumors and metastatic disease. Given the significant morbidity of these surgeries and with other current adjuvant therapies (e.g., radiation, chemotherapy), interest has grown in other methods of targeting tumors of the spine. Recent efforts have highlighted the tumor microenvironment, and specifically lactate, as central to tumorigenesis. Once erroneously considered a waste product that indicated hypoxia/hypoperfusion, lactate is now known to be at the center of whole-body metabolism, shuttling between tissues and being used as a fuel. Diffusion-driven transporters and the near-equilibrium enzyme lactate dehydrogenase (LDH) allow rapid mobilization of large stores of muscle glycogen in the form of lactate. In times of stress, catecholamines can bind muscle cell receptors and trigger the breakdown of glycogen to lactate, which can then diffuse out into circulation and be used as a fuel where needed. Hypoxia, in contrast, is rarely the reason for an elevated arterial [lactate]. Tumors were originally described in the 1920's as being "glucose-avid" and "lactate-producing" even in normoxia (the "Warburg effect"). We now know that a broad range of metabolic behaviors likely exist, including cancer cells that consume lactate as a fuel, others that may produce it, and still others that may change their behavior based on the local microenvironment. In this review we will examine the relationship between lactate and tumor metabolism with a brief look at spine-specific tumors. Lactate is a valuable fuel and potent signaling molecule that has now been implicated in multiple steps in tumorigenesis [e.g., driving vascular endothelial growth factor (VEGF) expression in normoxia]. Future work should utilize translational animal models to target tumors by altering the local tumor microenvironment, of which lactate is a critical part.

A retrospective analysis of the respiratory adjusted shock index to determine the presence of occult shock in trauma patients

BACKGROUND

The shock index (SI), calculated as hear rate/systolic blood pressure, is a simple hemodynamic marker that may be used to assess for the presence of occult shock in trauma patients. The normal range for a healthy adult patient is 0.5 to 0.7. Recently, studies have demonstrated that tachypnea is the most important predictor of cardiac arrest in hospital wards and is an important indicator of derangements across multiple organ systems. As such, we have sought to determine whether the inclusion of the patient's respiratory rate (RR) to the already existing SI (called the Respiratory Adjusted Shock Index [RASI]), calculated as hear rate/systolic blood pressure*(RR/10), will improve the overall diagnostic accuracy of detecting patients in early occult shock.

METHODS

A retrospective chart review over a 4-year period (2012-2016) at an urban, Level I trauma center was performed. All patients admitted to hospital for trauma were included in the study. Exclusion criteria were patients in traumatic arrest or in overt shock. Charts were reviewed for triage vital signs and point of care lactate drawn within 30 minutes of presentation. A lactate greater than 2 mmol/L was used to determine presence of hypoperfusion. The upper limit of normal for the RASI was calculated by multiplying the upper limit of the SI by 1.9 (RR of 19 divided by 10) and validated internally.

RESULTS

A total of 3,093 patients were included in this study. There was no difference in SI for patients discharged versus patients admitted, 0.6 (95% CI, 0.5-0.7) versus 0.7 (95% CI, 0.5-0.8) and a significant difference between the same groups of patients (discharged vs. admitted) for the RASI, 1.1 (95% CI, 1.04-1.18) versus 1.46 (95% CI, 1.35-1.55), respectively. Area under the curve for SI was 0.58 and for the RASI score was 0.94.

CONCLUSION

The RASI score improves diagnostic accuracy for detecting early occult shock in trauma patients when compared to the SI.

LEVEL OF EVIDENCE

Diagnostic, level II.

Prognostic Value of Blood Lactate and Lactate Clearance in Refractory Cardiac Arrest Treated by Extracorporeal Life Support

OBJECTIVE

During cardiac arrest (CA) resuscitation, an 'ischaemia-reperfusion' syndrome occurs leading to multiorgan failure reflected by an increase in blood lactate. Blood lactate is a diagnosis and prognosis biomarker in extracorporeal life support (ECLS), but its kinetic appears more informative to assess a patient's outcome. The aim of the present study was to describe the prognostic value of blood lactate and lactate clearance (LC) 3 (H3) and 6 h (H6) after the initiation of ECLS in the treatment of refractory CA.

METHODS

Patients admitted to the intensive care unit for refractory CA were included. Lactate measurements were performed at the initiation of ECLS (H0) and at H3 and H6 upon the initiation of ECLS. LC was measured from 0 to 3 h (LC03), 0 to 6 h (LC06) and 3 to 6 h (LC36). The primary endpoint was in-hospital mortality within 28 days.

RESULTS

Sixty-six patients were enrolled in the study. Lactate levels were higher in deceased patients. Increased mortality was observed with increasing levels of lactate at H3 and H6 and with decreasing LC03. Using logistic regression, an association was observed between mortality and lactate at H3 with an odds ratio (OR) of 1.21 (95% confidence interval (CI) 1.05-1.42); LC03, OR of 0.93 (95% CI 0.87-0.99) and LC06, OR of 0.96 (95% CI 0.92-0.99).

CONCLUSION

Blood lactate and LC within the first 3 h of ECLS in refractory CA are associated with mortality. LC is a more relevant parameter than blood lactate, taking into account both the production and elimination of lactate. We suggest to preferentially use LC to assess the patient's outcome.

[Inflammatory markers in diagnosis and prognosis of abdominal sepsis]

For today, it is necessary to recognize, that treatment of patients with abdominal sepsis remains the basic problem in urgent surgery due to the invariably high mortality. Early diagnostics and targeted therapy are the key points for improving of sepsis outcome. At present, researchers around the world have proposed a large number of biological markers for diagnosing sepsis and predicting mortality. Ideally, doctors can use biomarkers for risk stratification, diagnosing, monitoring of treatment effectiveness and outcome prediction. The biomarker is a laboratory parameter that can be objectively measured and characterized as an indicator of normal and pathological biological processes. The article presents the modern concept of the sepsis pathogenesis for understanding the role of various biomarkers and inflammatory indicators in its development. We have analyzed literature data and summarized information on the possible use of biological markers and their combinations in the early detection of sepsis, for monitoring sepsis and predicting its outcome.

Factors predicting the need for hemorrhage control intervention in patients with blunt pelvic trauma: a retrospective study

Background

Blunt pelvic injuries are often associated with pelvic fractures and injuries to the rectum and genitourinary tract. Pelvic fractures can lead to life-threatening hemorrhage, which is a common cause of morbidity and mortality in trauma. Thus, early identification of patients with pelvic fractures at risk severe bleeding requiring urgent hemorrhage control is crucial. This study aimed to investigate early factors predicting the need for hemorrhage control in blunt pelvic trauma.

Methods

The medical records of 1760 trauma patients were reviewed retrospectively between January 2013 and June 2018. We enrolled 187 patients with pelvic fracture due to blunt trauma who were older than 15 years. The pelvic fracture pattern was classified according to the Orthopedic Trauma Association/Arbeitsgemeinschaft fur Osteosynthesefragen (OTA/AO) classification. A multivariate logistic regression model was used to determine independent predictors of the need for pelvic hemorrhage control intervention.

Results

The most common pelvic fracture pattern was type A (54.5%), followed by types B (36.9%) and C (8.6%). Of 187 patients, 48 (25.7%) required pelvic hemorrhage control intervention. Hemorrhage control interventions were most frequently performed in patients with type B fractures (54.2%). Multivariate logistic regression analysis revealed that type B (odds ratio [OR] = 4.024, 95% confidence interval [CI] = 1.666–9.720, p = 0.002) and C (OR = 7.077, 95% CI = 1.781–28.129, p = 0.005) fracture patterns, decreased body temperature (OR = 2.275, 95% CI = 0.134–0.567, p < 0.001), and elevated serum lactate level (OR = 1.234, 95% CI = 1.061–1.435, p = 0.006) were factors predicting the need for hemorrhage control intervention in patients with blunt pelvic trauma.

Conclusion

Patients with type B and C fracture patterns on the OTA/AO classification, hypothermia, or an elevated serum lactate level are at risk for bleeding and require pelvic hemorrhage control intervention.

Electronic supplementary material

The online version of this article (10.1186/s12893-018-0438-8) contains supplementary material, which is available to authorized users.

Hyperlactatemia and the Importance of Repeated Lactate Measurements in Critically Ill Patients

Objective

The aim of the study was to describe the prevalence of hyperlactatemia and emphasis on repeated lactate measurements in critically ill patients, and the associated mortality.

Materials and methods

The study included 70 patients admitted in the Medical Intensive Care Unit at the Clinical Center, University of Sarajevo, in a 6-month period (July - December 2015). The following data were obtained: age, gender, reason for admission, Simplified Acute Physiology Score II, Acute Physiology and Chronic Health Evaluation, lactate concentrations upon admission, after 24 and 48 hours, and outcome (discharge from hospital or death).

Results

Upon admission,hyperlactatemia was present in 91.4% patients with a mean concentration of lactate 4.13 ±1.21 mmol/L. Lactate concentration at 48 hours was independently associated within creased in-hospital mortality (P = 0.018).

Conclusion

Persistent hyperlactatemia is associated with adverse outcome in critically ill patients. Lactate concentration at 48 hours is independently associated within creased in-hospital mortality and it represents a statistically significant predictive marker of fatal outcomes of patients. Blood lactate concentrations > 2.25 mmol/L should be used by clinicians to identify patients at higher risk of death.

Prognostic value of 2-hour lactate level and lactate clearance for 30-day mortality and comparison with trauma scores in multi-trauma patients

Objective:

Trauma scores are prone to misreading. Therefore, a readily available, objective way to estimate the mortality of the trauma patients is needed. We aimed to evaluate the prognostic utility of lactate levels, and clearance for 30-days mortality, and compare with the physiological trauma scores.

Methods:

All adult trauma patients (two hundred) admitted to ED were enrolled. Initial and 2-hour serum lactate levels were measured and components of GAP, MGAP, RTS, VIEWS and VIEWS-L trauma scores were calculated.

Results:

Final study population was 200 patients with a median age of 33 years. Mortality was 7/200 (3.5%) in 30-days. Both initial (2.3 vs. 7.7 mmol/L) and 2h-lactate (1.7 vs. 8.4 mmol/L) levels were significantly lower, and lactate clearance was significantly higher (23.8% vs. -12.0%) in survivors. Also, the change in the lactate level from 0h to 2h (2.3 vs. 1.7mmol/L) was significant in survivors, contrary to non-survivors (7.7 vs. 8.4mmol/L). VIEWS-L, VIEWS, two hour-lactate level and EMTRAS showed high specificity at the 100% sensitivity cut-offs, therefore, were the most valuable prognostic parameters in this study.

Conclusion:

Calculation of 2h-lactate clearance and evaluation of a 2h-lactate level may not be needed to predict long-term mortality if the initial lactate level is below 2.8mmol/L.

Status and Challenges of Predicting and Diagnosing Sepsis in Burn Patients

Burns are a common form of trauma that account for more than 300,000 deaths each year worldwide. Survival rates have improved over the past decades because of improvements in nutritional and fluid support, burn wound care, and infection control practices. Death, however, remains unacceptably high. The primary cause of death has changed over the last decades from anoxic causes to now predominantly infections and sepsis. Sepsis and septic complications are not only major contributors to poor outcomes, but they further result in longer hospital stay and higher healthcare costs. Despite the importance of infections and sepsis, the diagnosis and prediction remain a major challenge. To date, no clear diagnostic criteria or predictive formula exist that can predict reliably the occurrence of sepsis and infections. This review will highlight and discuss current definitions and criteria for diagnosis as well as predictive biomarkers of sepsis in patients with burns. It will also present the diagnostic tools employed, such as procalcitonin, C-reactive protein, and cytokines. We will discuss the benefits and shortcomings of different treatment modalities in the context of sepsis prevention. Last, we identify new therapeutic strategies for sepsis prediction and present future considerations to prevent sepsis in patients with burns. Minimizing and preventing septic complications through early detection would significantly benefit patients and necessitate continued research to unravel new biomarkers and mechanisms. Subsequent studies need to take a fresh perspective and consider the implementation of patient-centered therapeutic strategies.

Lactate metabolism: historical context, prior misinterpretations, and current understanding

Lactate (La^-) has long been at the center of controversy in research, clinical, and athletic settings. Since its discovery in 1780, La^- has often been erroneously viewed as simply a hypoxic waste product with multiple deleterious effects. Not until the 1980s, with the introduction of the cell-to-cell lactate shuttle did a paradigm shift in our understanding of the role of La^- in metabolism begin. The evidence for La^- as a major player in the coordination of whole-body metabolism has since grown rapidly. La^- is a readily combusted fuel that is shuttled throughout the body, and it is a potent signal for angiogenesis irrespective of oxygen tension. Despite this, many fundamental discoveries about La^- are still working their way into mainstream research, clinical care, and practice. The purpose of this review is to synthesize current understanding of La^- metabolism via an appraisal of its robust experimental history, particularly in exercise physiology. That La^- production increases during dysoxia is beyond debate, but this condition is the exception rather than the rule. Fluctuations in blood [La^-] in health and disease are not typically due to low oxygen tension, a principle first demonstrated with exercise and now understood to varying degrees across disciplines. From its role in coordinating whole-body metabolism as a fuel to its role as a signaling molecule in tumors, the study of La^- metabolism continues to expand and holds potential for multiple clinical applications. This review highlights La^-'s central role in metabolism and amplifies our understanding of past research.

The Evolving Science of Trauma Resuscitation

This review summarizes the evolution of trauma resuscitation from a one-size-fits-all approach to one tailored to patient physiology. The most dramatic change is in the management of actively bleeding patients, with a balanced blood product-based resuscitation approach (avoiding crystalloids) and surgery focused on hemorrhage control, not definitive care. When hemostasis has been achieved, definitive resuscitation to restore organ perfusion is initiated. This approach is associated with decreased mortality, reduced duration of stay, improved coagulation profile, and reduced crystalloid/vasopressor use. This article focuses on the tools and methods used for trauma resuscitation in the acute phase of trauma care.

Prehospital lactate improves accuracy of prehospital criteria for designating trauma activation level

BACKGROUND

Trauma activation level is determined by prehospital criteria. The American College of Surgeons (ACS) recommends trauma activation criteria; however, their accuracy may be limited. Prehospital lactate has shown promise in predicting trauma center resource requirements. Our objective was to investigate the added value of incorporating prehospital lactate in an algorithm to designate trauma activation level.

METHODS

Air medical trauma patients undergoing prehospital lactate measurement were included. Algorithms using ACS activation criteria (ACS) and ACS activation criteria plus prehospital lactate (ACS+LAC) to designate trauma activation level were compared. Test characteristics and net reclassification improvement (NRI), which evaluates reclassification of patients among risk categories with additional predictive variables, were calculated. Algorithms were compared to predict trauma center need defined as more than 1 unit of blood in the emergency department; spinal cord injury; advanced airway; thoracotomy or pericardiocentesis; ICP monitoring; emergent operative or interventional radiology procedure; or death.

RESULTS

There were 6,347 patients included. Twenty-eight percent had trauma center need. The ACS+LAC algorithm upgraded 256 patients and downgraded 548 patients compared to the ACS algorithm. The ACS+LAC algorithm versus ACS algorithm had an NRI of 0.058 (95% confidence interval [CI], 0.044-0.071; p < 0.01), with an event NRI of -0.5% and nonevent NRI of 6.2%. When weighted to favor changes in undertriage, the ACS+LAC still had a favorable overall reclassification (weighted NRI, 0.041; 95% CI, 0.028-0.054; p = 0.01). The ACS+LAC algorithm increased positive predictive value, negative predictive value, and accuracy. Over-triage was reduced 7.2%, while undertriage only increased 0.7%. The area under the curve was significantly higher for the ACS+LAC algorithm (0.79 vs. 0.76; p < 0.01).

CONCLUSIONS

The ACS+LAC algorithm reclassified patients to more appropriate levels of trauma activation compared to the ACS algorithm. This overall benefit is achieved by significant reduction in overtriage relative to very small increase in undertriage. In the context of trauma team activation, this trade-off may be acceptable, especially in the current health care environment.

LEVEL OF EVIDENCE

Therapeutic/care management study, level III; prognostic/epidemiologic study, level III.

Practical Use of Lactate Levels in the Intensive Care

Hyperlactatemia is a strong predictor of mortality in diverse populations of critically ill patients. In this article, we will give an overview of how lactate is used in the intensive care unit. We describe the use of lactate as a predictor of outcome, as a marker to initiate therapy and to monitor adequacy of initiated treatments.

Handheld Capillary Blood Lactate Analyzer as an Accessible and Cost-Effective Prognostic Tool for the Assessment of Death and Heart Failure Occurrence during Long-Term Follow-Up

Impact of tissue lactate accumulation on prognosis after acute myocardial infarction (AMI) is biased. The study aimed to assess the prognostic role of lactate concentration (LC) in patients with AMI during one year of follow-up. 145 consecutive patients admitted due to AMI were enrolled. The data on the frequency of endpoint occurrence (defined as I, death; II, heart failure (HF); and III, recurrent myocardial infarction (re-MI)) were collected. The patients were divided into group A (LC below the cut-off value) and group B (LC above the cut-off value) for the endpoints according to receiver operating characteristic (ROC) analysis. The cumulative survival rate was 99% in group I-A and 85% in group I-B (p = 0.0004, log-rank test). The HF-free survival rate was 95% in group II-A and 82% in group II-B (p = 0.0095, log-rank test). The re-MI-free survival rate did not differ between groups. A multivariate Cox analysis showed a statistically significant influence of LC on death [Hazard Ratio (HR): 1.41, 95% Confidence Interval (CI) (1.13–1.76), and p = 0.002] and HF [HR: 1.21, 95% CI (1.05–1.4), and p = 0.007] with no impact on re-MI occurrence. LC in capillary blood may be considered a useful prognostic marker of late-onset heart failure and death after AMI.

The 100 most cited manuscripts in emergency abdominal surgery: A bibliometric analysis

BACKGROUND

The number of citations a scientific article receives provides a good indication of its impact within any given field. This bibliometric analysis aimed to identify the 100 most cited articles in Emergency Abdominal Surgery (EAS), to highlight key areas of interest and identify those that have most significantly shaped contemporary clinical practice in this newly evolving surgical specialty. This is of increasing relevance as concerns grow regarding the variable and suboptimal outcomes in Emergency General Surgery.

MATERIALS AND METHODS

The Thomson Reuters Web of Science database was used to search using the terms [Emergency AND Abdom* AND Surg*] to identify all English language, full manuscripts. Results were ranked according to citation number. The top 100 articles were further analysed by subject, author, journal, year of publication, institution, and country of origin.

RESULTS

The median (range) citation number of the top 100 out of 7433 eligible papers was 131 (1569-97). The most cited paper (by Goldman et al., Massachusetts General Hospital, New England Journal of Medicine; 1569 citations) focused on cardiac risk stratification in non-cardiac surgery. The Journal of Trauma, Injury, Infection and Critical Care published the most papers and received most citations (n = 19; 2954 citations. The majority of papers were published by centres in the USA (n = 52; 9422 citations), followed by the UK (n = 13; 1816 citations). The most common topics of publication concerned abdominal aneurysm management (n = 26) and emergency gastrointestinal surgery (n = 26).

CONCLUSION

Vascular surgery, risk assessment and gastrointestinal surgery were the areas of focus for 59% of the contemporary most cited emergency abdominal surgery manuscripts. By providing the most influential references this work serves as a guide to what makes a citable emergency surgery paper.

Cambridge Polytrauma Pathway: Are we making appropriately guided decisions?

Addenbrooke's Hospital, the Major Trauma Centre for the East of England Trauma Network, received 1070 major trauma patients between 1st January and 31st December 2014. In order to improve care, an audit was performed of 59 patients meeting our own selection criteria for orthopaedic polytrauma between 1st January 2013 and 31st December 2013. The Cambridge Polytrauma Pathway was devised through NCEPOD guidelines, literature review, internal and external discussion. It facilitates provision of best practice Early Appropriate Care, encompassing - multidisciplinary consultant decisions around the patient in our Neurological and Trauma Critical Care Unit, early full body trauma CT scans, serial measurements of lactate and fibrinogen levels, and out-of-hours orthopaedic theatre reserved for life-and-limb threatening injuries. Re-audit was conducted of 15 patients meeting selection criteria, admitted between 1st October 2014 and 31st March 2015. Significant improvements in recording of lactate and fibrinogen were demonstrated, both on admission (lactate - p<0.000, fibrinogen - p=0.015), and preoperatively (lactate - p=0.003, fibrinogen - p=0.030). Time to trauma CT was unchanged (p=0.536) with a median time to CT of 0.53h at re-audit (IQR 0.48-0.75). The number of patients receiving definitive orthopaedic intervention out-of-hours reduced from 8 to zero (p=0.195). The approach of facilitating management decisions to be made at early daytime MDT meetings has been adopted. It is anticipated that this pathway will improve outcomes in orthopaedic polytrauma patients and it is recommended that either the GOS-E, or the EQ-5D scoring systems be introduced to assess this.

Trauma patients who present in a delayed fashion: a unique and challenging population

BACKGROUND

A proportion of trauma patients present for evaluation in a delayed fashion after injury, likely due to a variety of medical and nonmedical reasons. There has been little investigation into the characteristics and outcomes of trauma patients who present delayed. We hypothesize that trauma patients who present in a delayed fashion are a unique population at risk of increased trauma-related complications.

MATERIALS AND METHODS

This was a retrospective review from 2010-2015 at a Level I trauma center. Patients were termed delayed if they presented >24 hours after injury. Patients admitted within 24 hours of their injury were the comparison group. Charts were reviewed for demographics, mechanism, comorbidities, complications and outcomes. A subgroup analysis was done on patients who suffered falls.

RESULTS

During the 5-y period, 11,705 patients were admitted. A total of 588 patients (5%) presented >24 h after their injury. Patients in the delayed group were older (65 versus 55 y, P < 0.001) and more likely to have psychiatric comorbidities (33% vs. 24%, P = 0.0001) than the control group. They were also more likely to suffer substance withdrawal (8.9% vs. 4.1%, P < 0.001) but had toxicology testing for drugs and alcohol done at significantly lower rates. Patients that presented delayed after falls were similar in age and injury severity score (ISS) but more likely to suffer substance withdrawal when compared to those with falls that presented within 24 hours. Patients with falls that presented delayed had toxicology testing at significantly lower rates than the comparison group.

CONCLUSIONS

Trauma patients that present to the hospital in a delayed fashion have unique characteristics and are more likely to suffer negative outcomes including substance withdrawal. Future goals will include exploring strategies for early intervention, such as automatic withdrawal monitoring and social work referral for all patients who present in a delayed fashion.

Is Early Appropriate Care of axial and femoral fractures appropriate in multiply-injured elderly trauma patients?

BACKGROUND

Previous work established resuscitation parameters that minimize complications with early fracture management. This Early Appropriate Care (EAC) protocol was applied to patients with advanced age to determine if they require unique parameters to mitigate complications.

METHODS

Between October 2010 and March 2013, 376 consecutive skeletally mature patients with unstable fractures of the pelvis, acetabulum, thoracolumbar spine, and/or proximal or diaphyseal femur fractures were treated at a level I trauma center and were prospectively studied. Patients aged ≤30 years (n = 114), 30 to 60 years (n = 184), and ≥60 years (n = 37) with Injury Severity Scores (ISS) ≥16 and unstable fractures of the pelvis, acetabulum, spine, and/or diaphyseal femur were treated within 36 h, provided they showed evidence of adequate resuscitation. ISS, Glasgow Coma Scale (GCS), and American Society of Anesthesiologists (ASA) classification were determined. Lactate, pH, and base excess (BE) were measured at 8-h intervals. Complications included pneumonia, pulmonary embolism (PE), acute renal failure, acute respiratory distress syndrome (ARDS), multiple organ failure (MOF), deep vein thrombosis, infection, sepsis, and death.

RESULTS

Patients ≤30 years old (y/o) were more likely to sustain gunshot wounds (p = 0.039), while those ≥60 y/o were more likely to fall from a height (p = 0.002). Complications occurred at similar rates for patients ≤30 y/o, 30 to 60 y/o, and ≥60 y/o. There were no differences in lactate, pH, or BE at the time of surgery. For patients ≤30 y/o, there were increased overall complications if pH was <7.30 (p = 0.042) or BE <-6.0 (p = 0.049); patients ≥60 y/o demonstrated more sepsis if BE was <-6.0 (p = 0.046).

CONCLUSIONS

EAC aims to definitively manage axial and femoral shaft fractures once patients have been adequately resuscitated to minimize complications. EAC is associated with comparable complication rates in young and elderly patients. Further study is warranted with a larger sample to further validate EAC in elderly patients.

LEVEL OF EVIDENCE

level II prospective, comparative study.

The value of blood lactate kinetics in critically ill patients: a systematic review

BACKGROUND

The time course of blood lactate levels could be helpful to assess a patient's response to therapy. Although the focus of published studies has been largely on septic patients, many other studies have reported serial blood lactate levels in different groups of acutely ill patients.

METHODS

We performed a systematic search of PubMed, Science Direct, and Embase until the end of February 2016 plus reference lists of relevant publications. We selected all observational and interventional studies that evaluated the capacity of serial blood lactate concentrations to predict outcome. There was no restriction based on language. We excluded studies in pediatric populations, experimental studies, and studies that did not report changes in lactate values or all-cause mortality rates. We separated studies according to the type of patients included. We collected data on the number of patients, timing of lactate measurements, minimum lactate level needed for inclusion if present, and suggested time interval for predictive use.

RESULTS

A total of 96 studies met our criteria: 14 in general ICU populations, five in general surgical ICU populations, five in patients post cardiac surgery, 14 in trauma patients, 39 in patients with sepsis, four in patients with cardiogenic shock, eight in patients after cardiac arrest, three in patients with respiratory failure, and four in other conditions. A decrease in lactate levels over time was consistently associated with lower mortality rates in all subgroups of patients. Most studies reported changes over 6, 12 or 24 hrs, fewer used shorter time intervals. Lactate kinetics did not appear very different in patients with sepsis and other types of patients. A few studies suggested that therapy could be guided by these measurements.

CONCLUSIONS

The observation of a better outcome associated with decreasing blood lactate concentrations was consistent throughout the clinical studies, and was not limited to septic patients. In all groups, the changes are relatively slow, so that lactate measurements every 1-2 hrs are probably sufficient in most acute conditions. The value of lactate kinetics appears to be valid regardless of the initial value.

Multiple Procedures in the Initial Surgical Setting: When Do the Benefits Outweigh the Risks in Patients With Multiple System Trauma?

OBJECTIVES

To compare single versus multiple procedures in the same surgical setting. We hypothesized that complication rates would not be different and length of stay would be shorter in patients undergoing multiple procedures.

DESIGN

Prospective, cohort.

SETTING

Level 1 trauma center.

PATIENTS/PARTICIPANTS

A total of 370 patients with high-energy fractures were treated after a standard protocol for resuscitation to lactate <4.0 mmol/L, pH ≥7.25, or base excess (BE) ≥-5.5 mmol/L. Fractures included femur (n = 167), pelvis (n = 74), acetabulum (n = 54), and spine (n = 107).

MAIN OUTCOME MEASUREMENTS

Complications, including pneumonia, acute respiratory distress syndrome, infections, deep venous thrombosis, pulmonary embolism, sepsis, multiple organ failure, and death, and length of stay.

RESULTS

Definitive fixation was performed concurrently with another procedure in 147 patients. They had greater ISS (29.4 vs. 24.6, P < 0.01), more transfusions (8.9 U vs. 3.6 U, P < 0.01), and longer surgery (4:22 vs. 2:41, P < 0.01) than patients with fracture fixation only, but no differences in complications. When patients who had definitive fixation in the same setting as another procedure were compared only with other patients who required more than 1 procedure performed in a staged manner on different days (n = 71), complications were fewer (33% vs. 54%, P = 0.004), and ventilation time (4.00 vs. 6.83 days), intensive care unit (ICU) stay (6.38 vs. 10.6 days), and length of stay (12.4 vs. 16.0 days) were shorter (all P ≤ 0.03) for the nonstaged patients.

CONCLUSIONS

In resuscitated patients, definitive fixation in the same setting as another procedure did not increase the frequency of complications despite greater ISS, transfusions, and surgical duration in the multiple procedure group. Multiple procedures in the same setting may reduce complications and hospital stay versus additional surgeries on other days.

LEVEL OF EVIDENCE

Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Trauma Survival Margin Analysis: A Dissection of Trauma Center Performance through Initial Lactate

Measurement of trauma center performance presently relies on W-score calculation and comparison to national data sets. A limitation to this practice is a skewing of the W score, as it determines overall performance of a trauma population that is often heavily weighted by patients of low acuity. The University of Virginia relative mortality metric (RMM) was formulated to provide higher resolution in identifying areas of performance improvement within subpopulations of a trauma center using traditional Trauma Injury Severity Score methodology. Lactic acidosis has been established as a risk factor for mortality in the setting of trauma. This study aims to compare survival margin, defined as the area between actual and predicted mortality curves, in patients with either normal or elevated initial lactate. W score and RMM were calculated and compared in these cohorts. Whereas the W score suggested increased survival within the high initial lactate group, the RMM demonstrated the expected finding of increased survival margin in the normal lactate cohort. The RMM is a potentially valuable tool for trauma centers to monitor and improve performance. In addition, these findings validate the use of lactate as a triage and risk adjustment tool in the trauma setting.

Prognostic role of lactate on mortality in younger and older patients with cardio-respiratory failure admitted to an acute intensive care unit

BACKGROUND AND AIM

Acidosis is able to induce negative changes of different organs that increase progressively with aging. At present it is not known whether the levels of lactate may differently influence the prognosis of younger and older patients. Thus, the aim of this study is to evaluate the prognostic value of lactate levels after admission of younger and older patients to an acute intensive care unit.

METHODS

Younger (<65 years, n = 118) and older (≥65 years, n = 165) patients admitted to an acute intensive care unit were prospectively enrolled and classified according to diagnosis of acute heart or/and respiratory failure. For each patient, APACHE II score, time of hospitalization and mortality, blood levels of lactate were collected.

RESULTS

Both in-hospital mortality and lactate >2.5 mmol/L at the admission was higher in the older than in the younger patients (42.4 vs. 20.3 %, p < 0.01 and 57.8 vs. 31.9 %, p < 0.01, respectively). Lactate level was higher in older than in the younger patients both at admission and after 24 h (3.9 ± 3.4 vs. 2.4 ± 2.2 mmol/L and 2.4 ± 2.0 vs. 1.4 ± 1.3 mmol, p < 0.01, respectively). Accordingly, multivariate analysis shows that lactate was predictive of mortality in younger (OR = 2.65, 95 % CI 1.62-5.24, p = 0.03) and even more in the older (OR = 4.74, 95 % CI 2.10-6.70, p < 0.01) patients.

CONCLUSIONS

Lactate concentration increase is associated with increased mortality in younger patients but, even more so, in older patients admitted to an acute intensive care unit. These results confirm the experimental evidence showing acidosis has a greater effect of leading to organ failure and higher mortality with increasing age.

The Role of Elevated Lactate as a Risk Factor for Pulmonary Morbidity After Early Fixation of Femoral Shaft Fractures

OBJECTIVES

To evaluate lactate levels before reamed intramedullary nailing (IMN) of femur fractures treated with early fixation.

DESIGN

Retrospective study.

SETTING

Three academic, tertiary care trauma centers.

PATIENTS

Age ≥18 years, injury severity score ≥17, admission lactate ≥ 2.5 mmol/L, elevated preoperative lactate = preoperative lactate ≥ 2.5 mmol/L.

INTERVENTION

Reamed IMN of femur fracture within 24 hours.

MAIN OUTCOME MEASURE

Total duration of mechanical ventilation, pulmonary complications (PC) = duration of mechanical ventilation ≥5 days.

RESULTS

Four hundred and fourteen patients identified; 294/414 (71.0%) with admission lactate ≥ 2.5 mmol/L. No difference in PC among the groups (86/294, 29.3% vs. 28/120, 23.3%; P = 0.22). Median admission lactate: 3.7 (interquartile range: 3.0-4.6); median preoperative lactate: 2.8 (interquartile range: 1.9-3.5). 184/294 (62.6%) demonstrated an elevated preoperative lactate (≥ 2.5 mmol/L) before fracture fixation. No difference in elevated preoperative lactate and vent days (4.8 ± 9.9 vs. 3.9 ± 6.0, P = 0.41) or PC (50/86, 58.1% vs. 134/208, 64.4%; P = 0.31). There was no difference in PC when preoperative lactate was considered separately for a lactate ≥3.0 (34/123, 27.6% vs. 52/171, 30.4%; P = 0.61), ≥3.5 (21/79, 26.6% vs. 65/215, 30.2%; P = 0.54), or ≥4.0 (14/50, 28.0% vs. 72/244, 29.5%; P = 0.83). Multivariable linear regression modeling demonstrated that admission lactate [coefficient of variation: 0.84, standard error: 0.33, 95% confidence interval (CI): 0.20-1.49] was correlated with duration of mechanical ventilation, after adjusting for emergency department Glasgow Coma Scale, age, chest Abbreviated Injury Scale (AIS) score, abdominal AIS, and admission glucose. Logistic regression demonstrated admission lactate was also significantly associated with PC (odds ratio: 1.26, 95% CI: 1.03-1.53) after controlling for age, admission Glasgow Coma Scale, chest AIS, abdominal AIS, admission pulse and admission glucose; preoperative lactate was not a risk factor (odds ratio: 0.84, 95% CI: 0.65-1.09) for PC.

CONCLUSION

Median admission lactate of 3.7 mmol/L was associated with duration of mechanical ventilation ≥5 days, whereas median preoperative lactate of 2.8 mmol/L was not, when multisystem trauma patients with a femoral shaft fracture were treated with reamed IMN within 24 hours after admission.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.