The golden hour and the silver day: detection and correction of occult hypoperfusion within 24 hours improves outcome from major trauma

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.

Early Fluid is Less Fluid: Comparing Early Versus Late Resuscitation in Severely Injured Trauma Patients

Background

We aimed to characterize the temporal trends of crystalloid resuscitation in severely injured trauma patients after intensive care unit (ICU) admission. Using 500 mL/hr of crystalloid in the first 6 hours of ICU admission to distinguish early versus late resuscitation, we hypothesized early resuscitation was associated with less volume by 48 hours and better outcomes compared with late resuscitation.

Methods

We performed a retrospective review of the trauma registry of a high-volume level 1 academic trauma center to examine adult trauma patients admitted to the ICU (2016-2019) with: with initial serum lactate ≥ 4 mmol/dL, elevated lactate (≥ 2 mmol/L) at ICU admission, and lactate normalization within 48 hours. We analyzed patient and injury characteristics, and the first 48 hours of ICU course. The primary outcome was ICU length of stay (LOS); secondary outcomes included ventilator days, acute kidney injury (AKI), and in-hospital death. We compared subjects who received early resuscitation to those received late resuscitation using unadjusted methods and multivariable regression models.

Results

We analyzed 333 subjects. The late resuscitation group received less volume over the first 24 hours, but surpassed the early group by 48 hours (5.5 vs 4.1L, p ≤ 0.001). The late group had longer ICU LOS (9 vs 5 days, p ≤ 0.001) and ventilator days (5 vs 2 days, p ≤ 0.001), and higher incidence of AKI (38% vs 11%, p ≤ 0.001). On multivariable regression, late resuscitation remained associated with longer ICU LOS and ventilator days, and higher odds of AKI after adjusting for important confounders.

Conclusions

After hemostasis, crystalloid can play an important role in restoration of organ perfusion. Delaying resuscitation is associated with both receipt of higher volumes of crystalloid by 48 hours and worse outcomes compared to early resuscitation. Judicious crystalloid given early in ICU admission could improve outcomes in the severely injured.

An unusual case of symmetric quadruple limb fractures

A 19-year-old man had an accidental fall from the 2nd floor and sustained multiple injuries. On radiological evaluation, the patient had symmetrical quadruple limb involvement with bilateral humerus shaft, bilateral olecranon, bilateral femur shaft, and bilateral patella fractures. The patient was actively managed using damage control orthopaedics, and a sequence of skeletal fixation was planned based on the hemodynamic stability and periodical serum lactate assessment. Symmetrical quadruple limb fractures are very rare, which could be associated with higher mortality. A meticulous clinical evaluation, periodical blood parameter assessment and strict adherence to the principles of damage control orthopaedics can be conducive to prevent life-endangering complications.

Stress Hyperglycemia Secondary to Abdominal Emergency Mimicking Diabetic Ketoacidosis in a Pediatric Patient

Abdominal pain in a pediatric patient with diabetic ketoacidosis (DKA) can be mistaken for surgical or septic causes of acute abdomen. Both DKA and surgical abdominal emergencies can cause lactic acidosis (LA), which makes it challenging to differentiate between them. Fluid therapy resulting in quick alleviation of metabolic acidosis could be a valuable sign in differentiating surgical abdomen from DKA. In this report, we present a case of the surgical abdomen with stress hyperglycemia that mimicked DKA.

Definition of occult hypoperfusion in trauma: A systematic literature review

INTRODUCTION

Occult hypoperfusion (OH) entails inadequate tissue oxygenation in the presence of normal vital signs. Numerous studies have demonstrated that this phenomenon is associated with impaired outcome and increased mortality, however definitions of OH differ between studies. The aim of the current study was to identify and evaluate the published definitions of the term `occult hypoperfusion` in trauma (tOH).

MATERIAL & METHODS

A review of literature was performed using the Medline database. The following MeSH terms have been used: occult hypoperfusion, severe trauma, polytrauma, resuscitation. Clinical studies on OH were included and utilized definitions have been compared. A predefined data-interpretation process was applied to create an integrative definition for tOH.

RESULTS

A total of 43 publications used the term OH. A definition of OH was provided in 16 manuscripts. A pooled mean number of participants of 729 (SD: 1158) was found per study. The majority of manuscripts combine multiple parameters for inadequate tissue oxygenation and normal vital signs to define OH in trauma. In 12 manuscripts, specific cut-off values for hemodynamic parameters (SBP/PR/UP) and in 11/16 papers exact metabolic thresholds (lactate/B.E) were defined. The following definition best integrates definitions in current literature: Lactate > 2 mmol/l or BE <-3 mmol/l (to define inadequate oxygenation) plus SBP > 90 mmHg and PR < 120 bpm (to define normal macroperfusion).

CONCLUSIONS

The current systematic review demonstrates that definitions of occult hypoperfusion in trauma differ in the literature. The following comprehensive definition for (tOH) is proposed: Lactate > 2 mmol/l or BE <-3 mmol/l plus SBP > 90 mmHg and PR < 120 bpm. This recommendation appears to represent current literature on tOH and may improve the identification of trauma patients at risk for OH and related complicated courses. Further validation studies are required to demonstrate the clinical role of tOH and the proposed definition.

The prognostic value of delta-lactate in critically ill children

AIM

This study aimed to test delta-lactate (ΔL) as a short-term risk stratification method in critically ill children.

METHODS

An exploratory study of patients admitted to paediatric intensive care unit (PICU) was conducted. ΔL was calculated as the difference between the maximum lactate concentrations on Days 1 and 2. According to the ΔL cutoff, two groups were considered: low mortality risk (LMR) - ΔL ≥ 0.05 mmol/L - and high mortality risk (HMR) - ΔL < 0.05 mmol/L.

RESULTS

Mortality, both during PICU stay and at 28 days, was statistically associated with elevated serum lactate on D1 and D2, per se. For the 93 cases with elevated lactate on Day 1, and a ΔL cutoff of 0.05 mmol/L, the area under the ROC curve was 0.698 (95% confidence interval, 0.47-0.93). HMR patients scored higher PIM3, were not discharged home until 28 days, counted fewer ventilation-free days and needed renal replacement therapy more often.

CONCLUSION

Elevated lactate levels at admission, as well as applying the optimal cutoff for ΔL, allowed to predict short-term mortality: if an increase or minimal decrease in lactate maximum levels occurred from D1 to D2, death was almost eight times more probable. In critically ill children, delta-lactate predicts short-term outcome.

Alterations in tissue oxygen saturation measured by near-infrared spectroscopy in trauma patients after initial resuscitation are associated with occult shock

PURPOSE

Persistent occult hypoperfusion after initial resuscitation is strongly associated with increased morbidity and mortality after severe trauma. The objective of this study was to analyze regional tissue oxygenation, along with other global markers, as potential detectors of occult shock in otherwise hemodynamically stable trauma patients.

METHODS

Trauma patients undergoing active resuscitation were evaluated 8 h after hospital admission with the measurement of several global and local hemodynamic/metabolic parameters. Apparently hemodynamically stable (AHD) patients, defined as having SBP ≥ 90 mmHg, HR < 100 bpm and no vasopressor support, were followed for 48 h, and finally classified according to the need for further treatment for persistent bleeding (defined as requiring additional red blood cell transfusion), initiation of vasopressors and/or bleeding control with surgery and/or angioembolization. Patients were labeled as "Occult shock" (OS) if they required any intervention or "Truly hemodynamically stable" (THD) if they did not. Regional tissue oxygenation (rSO₂) was measured non-invasively by near-infrared spectroscopy (NIRS) on the forearm. A vascular occlusion test was performed, allowing a 3-min deoxygenation period and a reoxygenation period following occlusion release. Minimal rSO₂ (rSO₂min), Delta-down (rSO₂-rSO₂min), maximal rSO₂ following cuff-release (rSO₂max), and Delta-up (rSO₂max-rSO₂min) were computed. The NIRS response to the occlusion test was also measured in a control group of healthy volunteers.

RESULTS

Sixty-six consecutive trauma patients were included. After 8 h, 17 patients were classified as AHD, of whom five were finally considered to have OS and 12 THD. No hemodynamic, metabolic or coagulopathic differences were observed between the two groups, while NIRS-derived parameters showed statistically significant differences in Delta-down, rSO₂min, and Delta-up.

CONCLUSIONS

After 8 h of care, NIRS evaluation with an occlusion test is helpful for identifying occult shock in apparently hemodynamically stable patients.

LEVEL OF EVIDENCE

IV, descriptive observational study.

TRIAL REGISTRATION

ClinicalTrials.gov Registration Number: NCT02772653.

Need for intensive care admission based on point-of-care measurement of serum lactate levels in early trauma care

Trauma is the leading cause of preventable death in the world. The time delay in presentation and the lack of knowledge about the availability of early markers of severity assessment decrease the success of survivability. The serum lactate analyses help the intensivist in effective triaging and thereby sorting out the indeed need of trauma victims for early intensive care management. Moreover, it guides orthopaedic surgeons, on when they should impart definitive surgery on polytrauma patients. Serum lactate analysis is an excellent 'resuscitation predictor' and its value have well utilized for framing a resuscitation protocol in advanced trauma care. The objective of this review is to enlighten the usage of serum lactate analysis at the point of early trauma care. Nevertheless, it describes the application of a continuous lactate monitoring system using sensor-based technologies in sports as well as trauma medicine.

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.

Automated CT reformations reduce time and variability in trauma panscan exam completion

PURPOSE

To test the hypothesis that an automated post-processing workflow reduces trauma panscan exam completion times and variability.

METHODS

One-hundred-fifty consecutive trauma panscans performed between June 2018 and December 2019 were included, half before and half after implementation of an automated software-driven post-processing workflow. Acquisition and reconstruction timestamps were used to calculate total examination time (first acquisition to last reformation), setup time (between the non-contrast and contrast-enhanced acquisitions), and reconstruction time (for the contrast-enhanced reconstructions and reformations). The performing technologist was recorded and accounted for in analyses using linear mixed models to assess differences between the pre- and post-intervention groups.

RESULTS

Exam, setup, and recon times were (mean ± standard deviation) 33.5 ± 4.6, 9.2 ± 2.4, and 23.6 ± 4.7 min before and 27.8 ± 1.5, 8.9 ± 1.4, and 18.9 ± 1.7 min after intervention. These reductions of 5.7 and 4.7 min in the mean exam and recon times were statistically significant (p < 0.001) while the setup time was not (p = 0.49). The reductions in standard deviation were statistically significant for exam and recon times (p < 0.0001) but not for setup time (p = 0.13). All automated panscans were completed within 36 min, versus 65% with the traditional workflow.

CONCLUSION

Automation of image reconstruction workflow significantly decreased mean exam and reconstruction times as well as variability between exams, thus facilitating a consistently rapid imaging assessment, and potentially reducing delays in critical management decisions.

The Impact of Timing on Clinical and Economic Outcomes During Inter-ICU Transfer of Acute Respiratory Failure Patients: Time and Tide Wait for No One

Approximately one in 30 patients with acute respiratory failure (ARF) undergoes an inter-ICU transfer. Our objectives are to describe inter-ICU transfer patterns and evaluate the impact of timing of transfer on patient-centered outcomes.

Damage control in the intensive care unit: what should the intensive care physician know and do?

Damage control surgery has transformed the management of severely injured trauma patients. It was initially described as a three-step process that included bleeding control, abdominal cavity contamination, and resuscitation in the intensive care unit (ICU) before definitive repair of the injuries. When the patient is admitted into the ICU, the physician should identify all the physiological alterations to establish resuscitation management goals. These strategies allow an early correction of trauma-induced coagulopathy and hypoperfusion increasing the likelihood of survival. The objective of this article is to describe the physiological alterations in a severely injured trauma patient who undergo damage control surgery and to establish an adequate management approach. The physician should always be aware and correct the hypothermia, acidosis, coagulopathy and hypocalcemia presented in the severely injured trauma patients.

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.

Iterative heuristic design of temporal graphic displays with clinical domain experts

Conventional electronic health record information displays are not optimized for efficient information processing. Graphical displays that integrate patient information can improve information processing, especially in data-rich environments such as critical care. We propose an adaptable and reusable approach to patient information display with modular graphical components (widgets). We had two study objectives. First, reduce numerous widget prototype alternatives to preferred designs. Second, derive widget design feature recommendations. Using iterative human-centered design methods, we interviewed experts to hone design features of widgets displaying frequently measured data elements, e.g., heart rate, for acute care patient monitoring and real-time clinical decision-making. Participant responses to design queries were coded to calculate feature-set agreement, average prototype score, and prototype agreement. Two iterative interview cycles covering 64 design queries and 86 prototypes were needed to reach consensus on six feature sets. Interviewers agreed that line graphs with a smoothed or averaged trendline, 24-h timeframe, and gradient coloring for urgency were useful and informative features. Moreover, users agreed that widgets should include key functions: (1) adjustable reference ranges, (2) expandable timeframes, and (3) access to details on demand. Participants stated graphical widgets would be used to identify correlating patterns and compare abnormal measures across related data elements at a specific time. Combining theoretical principles and validated design methods was an effective and reproducible approach to designing widgets for healthcare displays. The findings suggest our widget design features and recommendations match critical care clinician expectations for graphical information display of continuous and frequently updated patient data.

Association of delayed time in the emergency department with the clinical outcomes for critically ill patients

BACKGROUND

Previous studies have shown the association of waiting time in the emergency department with the prognosis of critically ill patients, but these studies linking the waiting time to clinical outcomes have been inconsistent and limited by small sample size.

AIM

To determine the relationship between the waiting time in the emergency department and the clinical outcomes for critically ill patients in a large sample population.

DESIGN

A retrospective cohort study of 13 634 patients.

METHODS

We used the Medical Information Mart for Intensive Care III database. Multivariable logistic regression was used to determine the independent relationships of the in-hospital mortality rate with the delayed time and different groups. Interaction and stratified analysis were conducted to test whether the effect of delayed time differed across various subgroups.

RESULTS

After adjustments, the in-hospital mortality in the ≥6 h group increased by 38.1% (OR 1.381, 95% CI 1.221-1.562). Moreover, each delayed hour was associated independently with a 1.0% increase in the risk of in-hospital mortality (OR 1.010, 95% CI 1.008-1.010). In the stratified analysis, intensive care unit (ICU) types, length of hospital stay, length of ICU stay, simplified acute physiology score II and diagnostic category were found to have interactions with ≥6 h group in in-hospital mortality.

CONCLUSIONS

In this large retrospective cohort study, every delayed hour was associated with an increase in mortality. Furthermore, clinicians should be cautious of patients diagnosed with sepsis, liver/renal/metabolic diseases, internal hemorrhage and cardiovascular disease, and if conditions permit, they should give priority to transferring to the corresponding ICUs.

Intensive care unit strain and mortality risk in patients admitted from the ward in Australia and New Zealand

PURPOSE

ICU strain (low number of available beds) may be associated with a delay and altered threshold for ICU admission and adverse patient outcomes. We aimed to investigate the impact of ICU strain on hospital mortality in critically ill patients admitted from wards across Australia and New Zealand.

MATERIALS AND METHODS

Ward patient admitted to ICU and ICU bed data at 137 hospitals were accessed between January 2013 and December 2016. ICU strain was classified as low (≤0.5 patients admitted per available ICU bed in a 6-h block), medium (0.5 to ≤1) or high (>1). Logistic regression models were used to examine the relationship between ICU strain and hospital mortality.

RESULTS

57,844 ICU admissions were analysed, with the majority (64.4%) admitted to medium-strain ICUs. Those admitted to high-strain ICUs spent longer in hospital prior to ICU than medium-strain or low-strain ICUs. After adjusting for confounders those admitted to high-strain ICUs [OR 1.24 (95%CI 1.14-1.35)] or medium-strain ICUs [OR 1.18 (95%CI 1.09-1.27)], (p < 0.001) had a higher risk of death compared low-strain ICUs.

CONCLUSION

ICU strain is associated with longer times in hospital prior to ICU admission and was associated with increased risk of death in patients admitted from ward.

Simulated Volume-Based Regionalization of Complex Procedures: Impact on Spatial Access to Care

OBJECTIVE

This study simulates the regionalization of pancreatectomies to assess its impact on spatial access in terms of patient driving times.

BACKGROUND

Although policies to regionalize complex procedures to high-volume centers may improve outcomes, the impact on patient access is unknown.

METHODS

Patients who underwent pancreatectomies from 2005 to 2014 were identified from California's statewide database. Round-trip driving times between patients' home ZIP code and hospital addresses were calculated via Google Maps. Regionalization was simulated by eliminating hospitals performing <20 pancreatectomies/yr, and reassigning patients to the next closest hospital that satisfied the volume threshold. Sensitivity analyses were performed for New York and Medicare patients to assess for influence of geography and insurance coverage, respectively.

RESULTS

Of 13,317 pancreatectomies, 6335 (47.6%) were performed by hospitals with <20 cases/yr. Patients traveled a median of 49.8 minutes [interquartile range (IQR) 30.8-96.2] per round-trip. A volume-restriction policy would increase median round-trip driving time by 24.1 minutes (IQR 4.5-53.5). Population in-hospital mortality rates were estimated to decrease from 6.7% to 2.8% (P < 0.001). Affected patients were more likely to be racial minorities (44.6% vs 36.5% of unaffected group, P < 0.001) and covered by Medicaid or uninsured (16.3% vs 9.8% of unaffected group, P < 0.001). Sensitivity analyses revealed a 17.8 minutes increment for patients in NY (IQR 0.8-47.4), and 27.0 minutes increment for Medicare patients (IQR 6.2-57.1).

CONCLUSIONS

A policy that limits access to low-volume pancreatectomy hospitals will increase round-trip driving time by 24 minutes, but up to 54 minutes for 25% of patients. Population mortality rates may improve by 1.5%.

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.

Hybrid emergency room shows maximum effect on trauma resuscitation when used in patients with higher severity

BACKGROUND

The hybrid emergency room (ER) system is a novel trauma workflow that uses angio-computed tomography equipment in a trauma resuscitation room. Although the hybrid ER system decreases time to start surgery and endovascular treatments and improves mortality, the optimal target benefitting from this system remained unclear. We aimed to identify a subset of trauma patients likely to receive the greatest benefits from the hybrid ER.

METHODS

This retrospective cohort study was conducted in a tertiary hospital in Japan from August 2007 to January 2020. We consecutively included severe adult blunt trauma patients (Injury Severity Score [ISS], ≥16) and divided them into two groups: conventional group (August 2007 to July 2011) and hybrid ER (August 2011 to January 2020) group. We evaluated the association between the hybrid ER group and 28-day mortality using multivariable logistic regression analysis. The 28-day mortality trend during the study period was evaluated with restricted cubic spline analysis. To evaluate heterogeneity of effects within various patient severities, we evaluated whether the patients' ISS modified the effect of the hybrid ER on survival.

RESULTS

Among 1,050 trauma patients, the conventional group comprised 360 patients and the hybrid ER group comprised 690 patients. Injury Severity Score and probability of survival (Ps) were not significantly different between the groups. Twenty-eight-day mortality was significantly lower in the hybrid ER group (Ps-adjusted odds ratio, 0.48; 95% confidence interval, 0.32-0.71; p < 0.001). Restricted cubic spline analysis revealed that Ps-adjusted 28-day mortality sharply decreased approximately 200 days after installation of the hybrid ER. Increase of survival probabilities according to the increase of ISS was significantly improved in hybrid ER group (p = 0.014). Because ISS increased to >25, survival probabilities in the hybrid ER group were higher compared with those in the conventional group.

CONCLUSION

The hybrid ER may improve posttraumatic mortality, especially in patients with higher baseline severity.

LEVEL OF EVIDENCE

Therapeutic/care management, level IV.

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.

Delayed Neurosurgical Intervention in Traumatic Brain Injury Patients Referred From Primary Hospitals Is Not Associated With an Unfavorable Outcome

Background: Secondary transports of patients suffering from traumatic brain injury (TBI) may result in a delayed management and neurosurgical intervention, which is potentially detrimental. The aim of this study was to study the effect of triaging and delayed transfers on outcome, specifically studying time to diagnostics and neurosurgical management.

Methods: This was a retrospective observational cohort study of TBI patients in need of neurosurgical care, 15 years and older, in the Stockholm Region, Sweden, from 2008 throughout 2014. Data were collected from pre-hospital and in-hospital charts. Known TBI outcome predictors, including the protein biomarker of brain injury S100B, were used to assess injury severity. Characteristics and outcomes of direct trauma center (TC) and those of secondary transfers were evaluated and compared. Functional outcome, using the Glasgow Outcome Scale, was assessed in survivors at 6–12 months after trauma. Regression models, including propensity score balanced models, were used for endpoint assessment.

Results: A total of n = 457 TBI patients were included; n = 320 (70%) patients were direct TC transfers, whereas n = 137 (30%) were secondary referrals. In all, n = 295 required neurosurgery for the first 24 h after trauma (about 75% of each subgroup). Direct TC transfers were more severely injured (median Glasgow Coma Scale 8 vs. 13) and more often suffered a high energy trauma (31 vs. 2.9%) than secondary referrals. Admission S100B was higher in the TC transfer group, though S100B levels 12–36 h after trauma were similar between cohorts. Direct or indirect TC transfer could be predicted using propensity scoring. The secondary referrals had a shorter distance to the primary hospital, but had later radiology and surgery than the TC group (all p < 0.001). In adjusted multivariable analyses with and without propensity matching, direct or secondary transfers were not found to be significantly related to outcome. Time from trauma to surgery did not affect outcome.

Conclusions: TBI patients secondary transported to a TC had surgical intervention performed hours later, though this did not affect outcome, presumably demonstrating that accurate pre-hospital triaging was performed. This indicates that for selected patients, a wait-and-see approach with delayed neurosurgical intervention is not necessarily detrimental, but warrants further research.

Lactic Acidosis in Diabetic Ketoacidosis: A Marker of Severity or Alternate Substrate for Metabolism

PURPOSE

The lactate level is being increasingly used as a marker of severity of illness and prognosis in multitude of critical conditions. However, its role in diabetic ketoacidosis (DKA) is not well defined.

AIM

To determine the prevalence and clinical importance along with the underlying role of metformin in lactic acidosis (LA) in patients admitted with DKA.

METHODS

A 2-year prospective and observational study involving 62 consenting in hospital DKA patients. Plasma lactate level on arrival, its clinical significance and relationship with morbidity and mortality in patients with DKA was evaluated.

RESULTS

The prevalence of LA (lactate ≥2.5 mmol/l) among the study cohort was found to be 55% with significant LA (≥5 mmol/l) documented in 16%. The median lactate level was 2.55 mmol/l (interquartile range, 1.70-3.20). No significant difference in the severity of LA was seen with metformin use. Lactate correlated positively with initial plasma glucose (IPG) (P = 0.001) and APACHE-II Score (P = 0.002); correlated negatively with systolic blood pressure (P = 0.003), pH (P = 0.002) and severity of DKA (P = 0.001). After controlling for AKI, APACHE II score and blood pressure, lactate continued to correlate positively with IPG (P = 0.002). No mortality or significant morbidity was documented in the entire cohort.

CONCLUSIONS

LA has a significant presence in patients with DKA; however, it is not associated with mortality or significant morbidity. Moreover, there was no significant difference in severity of LA with metformin use. Elevated lactate levels may be an adaptation to provide alternate substrate for metabolism in the presence of hypoinsulinemic state. The study results provide rationale for large well-designed studies evaluating in-depth clinical relationship of lactate in DKA.

Different strokes: differences in the characteristics and outcomes of BCVI and non-BCVI strokes in trauma patients

Background

Although strokes are rare in trauma patients, they are associated with worse functional and cognitive outcomes and decreased mobility. Blunt cerebrovascular injury (BCVI)–related strokes and mortality have decreased, likely due to refined screening and treatment algorithms in trauma literature; however, there is a paucity of research addressing non-BCVI strokes in trauma. The purpose of this study is to evaluate the incidence, etiology, and risk factors of stroke in our trauma population in order to identify preventive strategies.

Methods

This study was a retrospective review of all adult trauma patients admitted to a level 1 trauma hospital who suffered a stroke during trauma admission from 2010 to 2017. Data were collected from the prospectively maintained trauma and stroke databases. Stroke etiology was determined by a vascular neurologist.

Results

Of the 43 674 adult trauma patients admitted during the study period, 99 (0.2%) were diagnosed with a stroke during the index admission. Twenty-one (21%) strokes were due to BCVI. Seventy-eight (79%) strokes were due to non-BCVI etiologies. Patients with non-BCVI strokes were older, less severely injured, and had more medical comorbidities compared with patients with a BCVI stroke. While patients with a BCVI stroke were more likely to suffer multiple traumatic injuries from MVC (76% vs 28%, p<0.001), non-BCVI strokes had more isolated extremity injuries from fall mechanism (55% vs 10%, p<0.001). Over the study period, the age and incidence of stroke and BCVI (p<0.001) increased. However, the rate of BCVI strokes decreased while the rate of non-BCVI strokes increased.

Discussion

The incidence of stroke has increased despite aggressive screening and treatment of BCVI. This increase is primarily due to non-BCVI strokes which are associated with advanced age and medical comorbidities after low mechanism traumatic injury. Medical optimization of comorbid conditions during trauma hospitalization will become increasingly important for stroke prevention as the population ages.

Level of evidence: Level III

Arterial lactate in traumatic brain injury - Relation to intracranial pressure dynamics, cerebral energy metabolism and clinical outcome

PURPOSE

High arterial lactate is associated with disturbed systemic physiology. Lactate can also be used as alternative cerebral fuel and it is involved in regulating cerebral blood flow. This study explored the relation of endogenous arterial lactate to systemic physiology, pressure autoregulation, cerebral energy metabolism, and clinical outcome in traumatic brain injury (TBI).

METHOD

A retrospective study including 115 patients (consent given) with severe TBI treated in the neurointensive care unit, Uppsala university hospital, Sweden, 2008-2018. Data from cerebral microdialysis, arterial blood gases, hemodynamics and intracranial pressure were analyzed the first ten days post-injury.

RESULTS

Arterial lactate peaked on day 1 post-injury (mean 1.7 ± 0.7 mM) and gradually decreased. Higher arterial lactate correlated with lower age (p-value < 0.05), higher Marshall score (p-value < 0.05) and higher arterial glucose (p-value < 0.001) in a multiple regression analysis. Higher arterial lactate was associated with poor pressure autoregulation (p-value < 0.01), but not to worse cerebral energy metabolism. Higher arterial lactate was also associated with unfavorable clinical outcome (p-value < 0.05).

CONCLUSIONS

High endogenous arterial lactate is a biomarker of poor systemic physiology and may disturb cerebral blood flow autoregulation.

Evaluation of an Anti-Thrombotic Continuous Lactate and Blood Pressure Monitoring Catheter in an In Vivo Piglet Model undergoing Open-Heart Surgery with Cardiopulmonary Bypass

Blood lactate and blood pressure measurements are important predictors of life-threatening complications after infant open-heart surgeries requiring cardiopulmonary bypass (CPB). We have developed an intravascular nitric oxide (NO)-releasing 5-Fr catheter that contains a lactate sensor for continuous in-blood lactate monitoring and a dedicated lumen for third-party pressure sensor attachment. This device has antimicrobial and antithrombotic properties and can be implanted intravascularly. The importance of this design is its ability to inhibit thrombosis, due to the slow release of NO through the surface of the catheter and around the electrochemical lactate sensors, to allow continuous data acquisition for more than 48 h. An in vivo study was performed using six piglets undergoing open-heart surgery with CPB and cardioplegic arrest, in order to mimic intra-operative conditions for infants undergoing cardiac surgery with CPB. In each study of 3 h, two 5-Fr NO-releasing lactate and blood-pressure monitoring catheters were implanted in the femoral vessels (arteries and veins) and the CPB circuitry to monitor changing lactate levels and blood pressures during and immediately after aortic cross-clamp removal and separation from CBP. Electrical signals continuously acquired through the sensors were processed and displayed on the device's display and via Bluetooth to a computer in real-time with the use of a two-point in vivo calibration against blood gas results. The study results show that lactate levels measured from those sensors implanted in the CPB circuit during CPB were comparable to those acquired by arterial blood gas measurements, whereas lactate levels measured from sensors implanted in the femoral artery were closely correlated with those acquired intermittently by blood gas prior to CPB initiation, but not during CPB. Blood pressure sensors attached to one lumen of the device displayed accurate blood pressure readings compared to those measured using an FDA approved pressure sensor already on the market. We recommend that the sensor be implanted in the CPB's circuit to continuously monitor lactate during CPB, and implanted in the femoral arteries or jugular veins to monitor lactate before and after CPB. Blood pressures dramatically drop during CPB due to lower blood flow into the lower body, and we suspect that the femoral arteries are likely collapsing or constricting on the implanted catheter and disrupting the sensor-to-blood contact. This study shows that the device is able to accurately and continuously monitor lactate levels during CPB and potentially prevent post-surgery complications in infants.

Effect of Delayed Admission to Intensive Care Units from the Emergency Department on the Mortality of Critically Ill Patients

Background: Increasing in emergency department need to critical care, the number of intensive care unit bed worldwide is inadequate to meet these applies. Objectives: The aim of this study was to investigate the effect of waiting for admission to the Intensive Care Unit (ICU) in the Emergency Department (ED) on the length of stay in the ICU and the mortality of critically ill patients. Methods: This retrospective cohort study carried out between January 2012 - 2019 patients admitted to the ICU of a training and research hospital. The data of 1297 adult patients were obtained by searching the Clinical Decision Support System. Results: The data of the patients were evaluated in two groups as those considered to be delayed and non-delayed. It was determined that the delay of two hours increased the risk of mortality 1.5 times. Hazard Ratios (HR) was 1.548 (1.077 - 2.224). Patients whose ICU admission was delayed by 5 - 6 hours were found to have the highest risk in terms of mortality (HR = 2.291 [1.503 - 3.493]). A statistically significant difference was found in the ICU mortality, 28-day and, 90-day mortality between the two groups. ICU mortality for all patients’ general was 25.2% (327/1297). This rate was 11.4% (55/481) in the non-delayed group and 33.3% (272/816) in the delayed group (P < 0.001). The 28-day mortality rate for all patients’ general was 26.9% (349/1297). This rate was found to be 13.5% (65/481) in the non-delayed group and 34.8% (284/816) in the delayed group (P < 0.001). The 90-day mortality for all patients’ general was 28.4% (368/1297). This rate was 14.1% (68/481) in the non-delayed group and 36.8% (300/816) in the delayed group (P < 0.001). Conclusions: Prolonged stay in the ED before admission to the ICU is associated with worse consequences, and increased mortality.

Early Lactate Values After Out-of-Hospital Cardiac Arrest: Associations With One-Year Outcome

BACKGROUND

Previous studies have shown associations between high admission serum lactate, lower lactate clearance, and increased short-term mortality after out-hospital cardiac arrest (OHCA). We studied whether lactate levels predict long- term outcome after OHCA.

METHODS

We included 458 OHCA patients with lactate measurements during intensive care unit (ICU) stay from the prospective FINNRESUSCI study. We evaluated thresholds for time-weighted (TW) mean lactate values for the first 24, 48, and 72 h. We analyzed lactate clearance and used multivariate regression to assess the prognostic value of the different measurement time points.

RESULTS

The admission lactate (median [IQR] 3.06 [2.68-3.44] mmol/L vs 4.76 [4.29-5.23] mmol/L) and the last measured lactate (0.98 [0.90-1.06] mmol/L vs 2.40 [2.03-2.78] mmol/L) were higher in non-survivors than in survivors, as were the lowest (0.73 [0.67-0.79] mmol/L vs 1.83 [1.52-2.14] mmol/L) and the highest (3.44 [3.05-3.83] mmol/L vs 5.25 [4.76-5.74] mmol/L) lactate values (all P < 0.001). Time-weighted mean lactate values for the first 24, 48, 72, and for the entire ICU stay were lower in patients with good outcome (P < 0.001). In multivariate backward regression models, time-weighted mean lactate for the entire ICU stay (OR 1.41 per mmol/L, CI 95% 1.08-1.86, P = 0.013) and the last measured lactate in the ICU (OR 2.16 per mmol/L, CI 95% 1.47-3.18, P < 0.001) were independent predictors of poor 1-year outcome.

CONCLUSIONS

In the present study time-weighted mean lactate values for the entire ICU stay, and the last measured lactate value in the ICU, but not admission lactate or lactate clearance were independent predictors of poor 1-year outcome.

Success Of An Expedited Emergency Department Triage Evaluation System For Geriatric Trauma Patients Not Meeting Trauma Activation Criteria

Background

Geriatric patients are at increased risk of injury following low-energy mechanisms and are less tolerant of injury. Current criteria for trauma team activation (TTA) often miss these injuries. We evaluated a novel triage process for an expedited Emergency Medicine Physician evaluation protocol (T3) for at-risk geriatric sub-populations not meeting trauma team activation (TTA) criteria.

Methods

Retrospective review of injured patients (≥65 years) from a Level II Trauma Center with an Injury Severity Score (ISS < 16), prior to (Pre-T3, Jan 2007-Oct 2009), and after (Post-T3, Jan 2010-Oct 2012), implementation of T3, as well as a contemporary period (CP, Jan 2013-Oct 2015). Demographics, physiologic variables, and timeliness of care were measured. Rates of ICU admission, operative procedures and lengths of stay and in-hospital mortality were compared for all periods. Logistic regression analysis determined variables independently associated with mortality.

Results

Post-T3, 49.2% of geriatric registry patients underwent T3 with a reduction in key time intervals. Median time to evaluation (42.1 mins vs 61.7 min, p<0.001), median time to CT (161.3 mins vs 212.9 mins, p<0.001) and EDLOS (364.6 mins vs 451.5 mins, p=0.023) were all reduced compared to non-expedited evaluations. There was no change in mortality after the implementation of the protocol.

Conclusion

The T3 protocol expedited patient evaluation of at-risk geriatric patients that would not otherwise meet TTA criteria. The new process met the goals of the American College of Surgeons Trauma Quality Improvement Program while conserving resources.

Near-simultaneous intensive care unit (ICU) admissions and all-cause mortality: a cohort study

PURPOSE

Prior studies have reported the adverse effects of strain on patient outcomes. There is a paucity of literature about a type of strain that may be caused by near-simultaneous intensive care unit (ICU) admissions. We hypothesized that when multiple admissions arrive nearly at the same time, the ICU teams are excessively strained, and this leads to unfavorable patient outcomes.

METHODS

This is a retrospective cohort study of consecutive adult patients admitted to an academic medical ICU of a tertiary referral center over five consecutive years. Primary outcomes were the all-cause hospital and ICU mortality.

RESULTS

We enrolled 13,234 consecutive ICU admissions during the study period. One-fourth of the admissions had an elapsed time since the last admission (ETLA) of < 55 min. Near-simultaneous admissions (NSA) had on average, a higher unadjusted odds ratio (OR) of ICU death of 1.16 (95% CI 1-1.35, P = 0.05), adjusted 1.23 (95% CI 1.04-1.44, P = 0.01), unadjusted hospital death of 1.11 (95% CI 0.99-1.24, P = 0.06), adjusted 1.20 (95% 1.05-1.35, P = 0.004), and a lower adjusted OR of home discharge of 0.91 (95% CI 0.84-0.99, P = 0.04). NSA was associated with 0.16 (95% CI 0.04-0.29, P = 0.01) added days in the ICU. For each incremental unit increase of the logarithmic transformation of ETLA [log (ETLA in minutes)], the average adjusted hospital mortality OR incrementally decreased by an added average OR of 0.93 (95% CI 0.89‒0.97, P = 0.001).

CONCLUSION

Our results suggest that near-simultaneous ICU admissions (NSA) are frequent and are associated with a dose-dependent effect on mortality, length of stay, and odds of home versus nursing facility discharge.

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.

Direct to operating room trauma resuscitation decreases mortality among severely injured children

BACKGROUND

Expediting evaluation and intervention for severely injured patients has remained a mainstay of advanced trauma care. One technique, direct to operating room (DOR) resuscitation, for selective adult patients has demonstrated decreased mortality. We sought to investigate the application of this protocol in children.

METHODS

All DOR pediatric patients from 2009 to 2016 at a pediatric Level I trauma center were identified. Direct to OR criteria included penetrating injury, chest injuries, amputations, significant blood loss, cardiopulmonary resuscitation, and surgeon discretion. Demographics, injury patterns, interventions, and outcomes were analyzed. Observed mortality was compared with expected mortality, calculated using Trauma Injury Severity Score methodology, with two-tailed t tests, and a p value less than 0.5 was considered significant.

RESULTS

Of 2,956 total pediatric trauma activations, 82 (2.8%) patients (age range, 1 month to 17 years) received DOR resuscitation during the study period. The most common indications for DOR were penetrating injuries (62%) and chest injuries (32%). Forty-four percent had Injury Severity Score (ISS) greater than 15, 33% had Glasgow Coma Scale (GCS) score of 8 or less, and 9% were hypotensive. The most commonly injured body regions were external (66%), head (34%), chest (30%), and abdomen (27%). Sixty-seven (82%) patients required emergent procedural intervention, most commonly wound exploration/repair (35%), central venous access (22%), tube thoracostomy (19%), and laparotomy (18%). Predictors of intervention were ISS greater than 15 (odds ratio, 14; p = 0.013) and GCS < 9 (odds ratio = 8.5, p = 0.044). The survival rate to discharge for DOR patients was 84% compared with an expected survival of 79% (Trauma Injury Severity Score) (p = 0.4). The greatest improvement relative to expected mortality was seen in the subgroup with penetrating trauma (84.5% vs 74.4%; p = 0.002).

CONCLUSION

A selective policy of resuscitating the most severely injured children in the OR can decrease mortality. Patients suffering penetrating trauma with the highest ISS, and diminished GCS scores have the greatest benefit. Trauma centers with appropriate resources should evaluate implementing similar policies.

LEVEL OF EVIDENCE

Diagnostic tests or criteria, level II.

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.

Impact of triage-to-admission time on patient outcome in European intensive care units: A prospective, multi-national study

PURPOSE

Ubiquitous bed shortages lead to delays in intensive care unit (ICU) admissions worldwide. Assessing the impact of delayed admission must account for illness severity. This study examined both the relationship between triage-to-admission time and 28-day mortality and the impact of controlling for Simplified Acute Physiology Score (SAPS) II scores on that relationship.

METHODS

Prospective cross-sectional analysis of referrals to eleven ICUs in seven European countries between 2003 and 2005. Outcomes among patients admitted within versus after 4 h were compared using a Chi-square test. Triage-to-admission time was also analyzed as a continuous variable; outcomes were assessed using a non-parametric Kruskal-Wallis test.

RESULTS

Among 3175 patients analyzed, triage-to-admission time was 2.1 ± 3.9 h. Patients admitted within 4 h had higher SAPS II scores (33.6 versus 30.6, Pearson correlation coefficient -0.07, p < 0.0001). 28-day mortality was surprisingly higher among patients admitted earlier (29.6 vs 25.2%, OR 1.25, 95% CI 0.99-1.58, p = 0.06). Even after adjusting for SAPS II scores, delayed admission was not associated with higher mortality (OR 1.08, CI 0.83-1.41, p = 0.58).

CONCLUSIONS

Even after accounting for quantifiable parameters of illness severity, delayed admission did not negatively impact outcome. Triage practices likely influence outcomes. Severity scores may not fully reflect illness acuity or trajectory.

Clinical scenarios for use of transvalvular microaxial pumps in acute heart failure and cardiogenic shock - A European experienced users working group opinion

For patients with myocardial infarct-related cardiogenic shock (CS), urgent percutaneous coronary intervention is the recommended treatment strategy to limit cardiac and systemic ischemia. However, a specific therapeutic intervention is often missing in non-ischemic CS cases. Though drug treatment with inotropes and/or vasopressors may be required to stabilize the patient initially, their ongoing use is associated with excess mortality. Coronary intervention in unstable patients often leads to further hemodynamic compromise either during or shortly after revascularization. Support devices like the intra-aortic balloon pump failed to improve clinical outcomes in infarct-related CS. Currently, more powerful and active hemodynamic support devices unloading the left ventricle such as transvalvular microaxial pumps are available and are being increasingly used. However, as for other devices large randomized trials are not yet available, and device use is based on registry data and expert consensus. In this article, a multidisciplinary group of experienced users of transvalvular microaxial pumps outlines the pathophysiological background on hemodynamic changes in CS, the available mechanical support devices, and current guideline recommendations. Furthermore, different hemodynamic situations in several case-based scenarios are used to illustrate candidate settings and to provide the theoretic and scientific rationale for left-ventricular unloading in these scenarios. Finally, organization of shock networks, monitoring, weaning, and typical complications and their prevention are discussed.

Hepatic and Renal Biochemical Markers as Predictors of Mortality Among Critically Ill Systemic Inflammatory Response Syndrome Patients

Systemic inflammatory response syndrome (SIRS) is a frequently encountered complication seen in intensive care unit patients and remains a common cause of mortality. Assessing prognosis of those becomes a priority and indeed we have various efficient scoring systems for the same. However they use enormous data and involve complex calculations for scoring. We intended to find a simple, inexpensive, accurate diagnostic tool of certain markers to predict mortality outcome among critically ill SIRS patients and to evaluate their efficiency in comparison to Acute Physiology and Chronic Health Evaluation II (APACHE II) scoring system. Eighty-seven patients were selected and general hepatic, renal and urinary investigations were done for them at 24 h of admission and were followed up for a period of 4 weeks from admission date to classify them as survivors and non-survivors. Twenty-one percent patients had succumbed to death during study period. Urine albumin-creatinine ratio, alanineaminotransferase, aspartate aminotransferase and prothrombin time/International Normalized Ratio were found to be correlating with APACHE II scores and mortality significantly. Specific individual cut-offs were found for these parameters and were combined to form combined predictors which showed good discrimination (AUC = 0.715) and good calibration (p = 0.811) with specificity of 98.6% in predicting mortality. SIRS patients falling above combined predictor's cutoff are 54 times more likely to have an unfavorable outcome compared to the ones below. Overall predictive accuracy of first day combined predictors was such that within 24 h of ICU admission 87% of ICU SIRS admissions could be given a risk estimate for hospital death.

Changes in central venous oxygen saturation, lactates, and ST segment changes in a V lead ECG with changes in hemoglobin in neurosurgical patients undergoing craniotomy and tumor excision: A prospective observational study

Background and Aims:

The aim of the study was to observe the trends in central venous oxygen saturation (ScvO₂), lactate, and ST segment changes with change in hemoglobin in patients undergoing acute blood loss during surgery and to assess their role as blood transfusion trigger.

Material and Methods:

Seventy-seven consecutive patients undergoing craniotomy at a tertiary care institution were recruited for this study after obtaining written, informed consent. After establishing standard monitoring, anesthesia was induced with standard anesthetic protocol. Hemodynamic parameters such as heart rate, blood pressure (mean, systolic, diastolic), pulse pressure variation (PPV), and physiological parameters such as lactate, ScvO₂, ST segment changes were checked at baseline, before and after blood transfusion and at the end of the procedure.

Statistical Analysis:

Comparison of the mean and standard deviation for the hemodynamic parameters was performed between the transfused and nontransfused patient groups. Pearson correlation test was done to assess the correlation between the covariates. Receiver operating characteristic (ROC) curve was constructed for the ScvO₂ variable, which was used as a transfusion trigger and the cutoff value at 100% sensitivity and 75% specificity was constructed. Linear regression analysis was done between the change in hemoglobin and the change in ScvO₂ and change in hemoglobin and change in the ST segment.

Results:

There was a statistically significant positive correlation between the change in ScvO₂ and change in hemoglobin during acute blood loss with a regression coefficient of 0.8 and also between change in ST segment and hemoglobin with a regression coefficient of –0.132. No significant change was observed with lactate. The ROC showed a ScvO₂ cutoff of 64.5% with a 100% sensitivity and 75% specificity with area under curve of 0.896 for blood transfusion requirement.

Conclusions:

We conclude that ScvO₂ and ST change may be considered as physiological transfusion triggers in patients requiring blood transfusion in the intraoperative period.

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.

Predictive Value of Point-of-care Lactate Measurement in Patients Meeting Level II and III Trauma Team Activation Criteria that Present to the Emergency Department: A Prospective Study

Background

The aim of this study was to investigate the utility of early point-of-care (POC) lactate levels to help predict injury severity and ultimate emergency department (ED) disposition for trauma patients meeting Level II and III activation criteria.

Methods

This was a blinded, prospective cohort study including a convenience sample of patients meeting our triage criteria for Level II or III team activation with stable vital signs. Bedside lactate samples were collected during the secondary survey. Clinical care/disposition was at the discretion of physicians who remained blinded to the bedside lactate result. An elevated lactate was defined as >2.0 mmol/L.

Results

Ninety-six patients were in the study group; mean age was 41 ± 17 years, 26% were female, 57% were Hispanic, and 60% admitted. We found no difference in initial mean POC lactate levels (mmol/L) for admitted versus discharged groups and Injury Severity Score (ISS) ≥9 versus ISS <9 groups (3.71 [95% confidence interval (CI): 3.1-4.4] vs. 3.85 [95% CI: 2.8-4.9]; P = 0.99 and 3.54 [95% CI: 2.7-4.4] vs. 3.89 [95% CI: 3.1-4.6]; P = 0.60, respectively). Performance characteristics of early elevated lactate levels were poor both to predict need for hospital admission (sensitivity = 77% [65%-87%]; specificity = 26% [13%-43%]; negative predictive value [NPV] = 43% [27%-61%]; and positive predictive value [PPV] = 62% [56%-67%]) and to identify patients with ISS scores ≥9 (sensitivity = 76% [59%-89%]; specificity = 24% [14%-37%]; NPV = 65% [47%-80%]; and PPV = 36% [30%-41%]).

Conclusions

For Level II/III, we found that early bedside lactate levels were not predictive of ISS ≥9 or the need for admission.

Level of Evidence

III (diagnostic test).

Planning and understanding the intensive care network in the State of Rio de Janeiro (RJ), Brazil: a complex societal problem

Objectives

To determine the optimal number of adult intensive care unit beds to reduce patient's queue waiting time and to propose policy strategies.

Methods

Multimethodological approach: (a) quantitative time series and queueing theory were used to predict the demand and estimate intensive care unit beds in different scenarios; (b) qualitative focus group and content analysis were used to explore physicians' attitudes and provide insights into their behaviors and belief-driven healthcare delivery changes.

Results

A total of 33,101 requests for 268 regulated intensive care unit beds in one year resulted in 25% admissions, 55% queue abandonment and 20% deaths. Maintaining current intensive care unit arrival and exit rates, there would need 628 beds to ensure a maximum wait time of six hours. A reduction of the current abandonment rates due to clinical improvement or the average intensive care unit length of stay would decrease the number of beds to 471 and 366, respectively. If both were reduced, the number would reach 275 beds. The interviews generated 3 main themes: (1) the doctor's conflict: fair, legal, ethical and shared priorities in the decision-making process; (2) a failure of access: invisible queues and a lack of infrastructure; and (3) societal drama: deterioration of public policies and health care networks.

Conclusion

The queue should be treated as a complex societal problem with a multifactorial origin requiring integrated solutions. Improving intensive care unit protocols and reengineering the general wards may decrease the length of stay. It is essential to redefine and consolidate the regulatory centers to organize the queue and provide available resources in a timely manner, by using priority criteria, working with stakeholders to guarantee clinical governance and network organization.

Traditional approach versus Stewart approach for acid-base disorders: Inconsistent evidence

Purpose

The traditional approach and the Stewart approach have been developed for evaluating acid-base phenomena. While some experts have suggested that the two approaches are essentially identical, clinical researches have still been conducted on the superiority of one approach over the other one. In this review, we summarize the concepts of each approach and investigate the reasons of the discrepancy, based on current evidence from the literature search.

Methods

In the literature search, we completed a database search and reviewed articles comparing the Stewart approach with the traditional, bicarbonate-centered approach to November 2016.

Results

Our literature review included 17 relevant articles, 5 of which compared their diagnostic abilities, 9 articles compared their prognostic performances, and 3 articles compared both diagnostic abilities and prognostic performances. These articles show a discrepancy over the abilities to detect acid-base disturbances and to predict patients' outcomes. There are many limitations that could yield this discrepancy, including differences in calculation of the variables, technological differences or errors in measuring variables, incongruences of reference value, normal range of the variables, differences in studied populations, and confounders of prognostic strength such as lactate.

Conclusion

In conclusion, despite the proposed equivalence between the traditional approach and the Stewart approach, our literature search shows inconsistent results on the comparison between the two approaches for diagnostic and prognostic performance. We found crucial limitations in those studies, which could lead to the reasons of the discrepancy.