Returning from the acidotic abyss: Mortality in trauma patients with a pH < 7.0

Recovery to normal vital functions and acid-base status after a severe trauma in Level I versus Level II Trauma Centres

PURPOSE

In the Netherlands, approximately 70% of severely injured patients (ISS ≥ 16) are transported directly to a Level I trauma center. This study compared the time needed to return to normal vital parameters and normal acid-base status in severely injured patients and some in-hospital processes in Level I versus Level II trauma centers.

METHODS

This retrospective cohort study included all adult severely injured patients or adult trauma patients admitted to the intensive care unit between 2015 and 2020 in a Dutch trauma region. The primary endpoint was time until normal vital parameters and acid-base status. Secondary endpoints were complication rate, hospital length of stay, emergency department length of stay, and time until a computed tomography (CT) scan.

RESULTS

A total of 2345 patients were included. Patients admitted to a Level I trauma center had a significantly higher rate of normalization of vital parameters over time (HR 1.51). There was no significant difference in normalization rate of the acid-base status over time (HR 1.10). In Level I trauma centers, time spent at the emergency department and time until the CT scan was significantly shorter (respectively, β - 38 min and β - 77 min), and the complication rate was significantly lower (OR 0.35).

CONCLUSION

Severely injured patients admitted to a Level I trauma center require less time to normalize their vital functions. Level I centers are better equipped, resulting in better in-hospital processes with shorter time at the emergency department and shorter time until a CT scan.

Benefit of balance? Odds of survival by unit transfused: Retrospective analysis of the ACS-TQIP database

BACKGROUND

The critical blood shortage in January 2022 threatened the availability of blood. Utility of transfusion per unit was reported in a previous study, revealing patients receiving balanced transfusion are more likely to die after 16 units of packed red blood cells. We aimed to validate this study using a larger database.

METHODS

Retrospective analysis utilizing the American College of Surgeons Trauma Quality Improvement Program was performed. Trauma patients aged ≥16 receiving transfusion within 4 hours of arrival were included and excluded if they died in the emergency department, received <2 units of packed red blood cells, did not receive fresh frozen plasma, or were missing data. Primary outcome was mortality. Subgroups were balanced transfusion if receiving ≤2:1 ratio of packed red blood cells:fresh frozen plasma, and unbalanced transfusion if >2:1 ratio.

RESULTS

A total of 17,047 patients were evaluated with 28% mortality (4,822/17,408). Multivariable logistic regression identified advancing age (odds ratio 1.03 95% confidence interval 1.03-1.04), higher ISS (odds ratio 1.04, 95% confidence interval 1.03-1.04), and lower GCS (odds ratio 0.82, 95% confidence interval 0.82-0.83) as risk factors for mortality. Protective factors were balanced transfusion (odds ratio 0.81 95% confidence interval 0.71-0.93), male sex (odds ratio 0.90, 95% confidence interval 0.81-0.99), and blunt mechanism (odds ratio 0.74, 95% confidence interval 0.67-0.81). At 11 units of packed red blood cells, balanced transfusion patients were more likely to die (odds ratio 0.88, 95% confidence interval 0.80-0.98). Balanced transfusion patients survived at a higher rate for each unit of packed red blood cells, between 6 and 23 units of packed red blood cells.

CONCLUSION

Mortality increases with each unit of packed red blood cell transfused. At 11 units of packed red blood cells, mortality is the more likely outcome. Balanced transfusion improves the chance of survival through 23 units of packed red blood cells.

Factors contributing to death of major trauma victims with haemorrhage: A retrospective case-control study

OBJECTIVE

To identify factors associated with death secondary to haemorrhage following major trauma.

METHODS

A retrospective case-control study was conducted on data from adult major trauma patients attending Christchurch Hospital ED between 1 June 2016 and 1 June 2020. Cases (those who died due to haemorrhage or multiple organ failure [MOF]), were matched to controls (those who survived) in a 1:5 ratio from the Canterbury District Health Board major trauma database. A multivariate analysis was used to identify potential risk factors for death due to haemorrhage.

RESULTS

One thousand, five hundred and forty major trauma patients were admitted to Christchurch Hospital or died in ED during the study period. Of them, 140 (9.1%) died from any cause, most attributed to a central nervous system cause of death; 19 (1.2%) died from haemorrhage or MOF. After controlling for age and injury severity, having a lower temperature on arrival in ED was a significant modifiable risk factor for death. Additionally, intubation prior to hospital, increased base deficit, lower initial haemoglobin and lower Glasgow Coma Scale were risk factors associated with death.

CONCLUSIONS

The present study reaffirms previous literature that lower body temperature on presentation to hospital is a significant potentially modifiable variable in predicting death following major trauma. Further studies should investigate whether all pre-hospital services have key performance indicators (KPIs) for temperature management, and causes for failure to reach these. Our findings should promote development and tracking of such KPIs where they do not already exist.

Biochemical disturbance in damage control resuscitation: mechanisms, management and prognostic utility

PURPOSE OF REVIEW

With advances in resuscitative techniques, trauma patients are surviving increasingly severe injuries and physiological insult. Timely recognition of futility remains important in terms of patient dignity and resource preservation yet is increasingly challenging in the face of these advances. The understanding of biochemical derangement from pathophysiological processes of trauma and iatrogenic effects of resuscitation has expanded recently.

RECENT FINDINGS

Acidosis and hypocalcaemia have been recognized as important contributors to mortality among trauma patients. Although less well recognized and studied, critical injury and high blood product volume resuscitation render patients vulnerable to life-threatening hyperkalaemia. The methods of correcting disruptions to acid-base and electrolyte homeostasis during damage control resuscitation have changed little recently and often rely on evidence from undifferentiated populations. Biochemical disturbances have value as ancillary predictors of futility in trauma resuscitation.

SUMMARY

These findings will contribute to a greater understanding among anaesthesiologists of the causative mechanisms and effects of biochemical derangement after severe injury and aid them in the delivery of well tolerated and effective damage control resuscitation. Gaps in the evidence base are highlighted to encourage future work.

Predicting Futility in Severely Injured Patients: Using Arrival Lab Values and Physiology to Support Evidence-Based Resource Stewardship

BACKGROUND

The recent pandemic exposed a largely unrecognized threat to medical resources, including daily available blood products. Some of the most severely injured patients who arrive in extremis consume tremendous resources yet succumb shortly after arrival. We sought to identify cut points available early in the patient's resuscitation that predicted 100% mortality.

STUDY DESIGN

Cut points were developed from a previously collected data set of all level 1 trauma patients admitted January 2010 to December 2016. Objective values available on or shortly after arrival were evaluated. Once generated, we then validated these variables against (1) a prospective data set November 2017 to October 2021 of severely injured patients and (2) a multicenter, randomized trial of hemorrhagic shock patients. Analyses were conducted using STATA 17.0 (College Station, TX), generating positive predictive value (PPV), negative predictive value, sensitivity, and specificity.

RESULTS

The development data set consisted of 9,509 patients (17% mortality), with 2,137 (24%) and 680 (24%) in the two validation data sets. Several combinations of arrival vitals and labs had 100% PPV. Patients undergoing CPR in the field or on arrival (with subsequent return of spontaneous circulation) required lower fibrinolysis LY-30 (30%) than those with systolic blood pressures of ≤50 (30 to 50%), ≤70 (80 to 90%), and ≤90 mmHg (90%). Using a combination of these validated variables, the Suspension of Transfusions and Other Procedures (STOP) criteria were developed, with each element predicting 100% mortality, allowing physicians to cease further resuscitative efforts.

CONCLUSIONS

The use of evidence-based STOP criteria provides cut points of futility to help guide early decisions for discontinuing aggressive treatment of severely injured patients arriving in extremis.

The Association Between Serum Lactate Concentration, Base Deficit, and Mortality in Polytrauma Patients as a Prognostic Factor: An Observational Study

Introduction

In polytrauma patients, it is crucial to identify the severity of the injuries to ensure patient safety and survival. Polytrauma leads to hypotension and hypoperfusion, which results in an anaerobic metabolism with acidosis and a decrease in base excess. Thus, blood lactate levels above a certain threshold indicate the existence of global tissue hypoxia, which is a precursor to shock and multiple organ dysfunction syndrome (MODS). The serum lactate and base deficit (BD) levels are used in polytrauma patients as measures of damage severity and resuscitation endpoints and as a way to evaluate therapy efficacy and to predict outcomes. Thus, arterial blood gas analysis is of great value in assessing the status and prognosis of patients with polytrauma. There are few comparative studies on the predictive values of these markers in trauma patients. To determine which measure can more accurately predict the prognosis of polytrauma patients, the present study investigated the predictive values of mortality of these indicators for mortality within 48 hours of admission to the emergency room (ER) in patients with polytrauma.

Methods

This prospective study was designed for a single tertiary care center in northern India. We included 90 patients with polytrauma who were between the ages of 18 and 70 years, with the exception of pregnant women, who presented to the ER within six hours of injury with an injury severity score (ISS) >16, serum lactate level >2.0 mmol/L, and BD -4.0 mEq/L at the time of admission. If the patient's ISS was >16 at the time of ER presentation, arterial blood samples were drawn to determine the serum lactate and BD level at the time of admission and at 12, 24, and 48 hours intervals after ER admission. The primary outcome was the change in serum lactate and BD level in polytrauma. The secondary outcomes were an association of serum lactate and BD with mortality and the correlation between serum lactate with the BD and ISS with mortality of polytrauma patients. The timing of all outcome assessments was at 48 hours after each patient's ER admission.

Results

Lactate clearance from 0-12 hours (t = 2.28, p <0.05), 0-24 hours (t = 6.01, p <0.001), and 0-48 hours (t = 7.98, p <0.001) and a correction in BD from 0-24 (t = 2.68, p <0.01 ) and 0-48 hours (t = 5.46, p <0.001) were significantly higher in nonsurvivors as compared with survivors. In survivors and nonsurvivors, mean serum lactate levels (2.46 ± 1.46 versus 4.15 ± 2.99, t = 3.31, p <0.001, 95%Cl) and mean BD (-3.17 ± 2.58 versus -6.5 ± 4.91, t = 3.86, p <0.001, 95%CI) had a statistically significant difference. The serum lactate and BD levels at time of ER admission (r L0, BD0 = -0.765, p <0.01) and 48 hours after ER admission (r L48, BD 48 = -0.652, p <0.001) were highly negatively correlated.

Conclusion

In polytrauma patients, serum lactate and BD are simple, quick, and independent biochemical predictors of 48-hour mortality, and this single arterial blood test would thereby improve decision-making for resuscitation effectiveness. Prolonged lactate and BD normalization time were associated with higher mortality. Serum lactate and BD are negatively correlated. A higher ISS at admission was associated with a higher incidence of mortality in polytrauma patients.

Massive transfusion and severe blood shortages: establishing and implementing predictors of futility

Massive transfusion protocols were developed to deliver blood for life-threatening haemorrhage; however, there are no guidelines to advise when massive transfusion protocols may be considered futile. Early recognition of clinical futility remains a challenge as studies have not identified variables that can accurately determine early mortality. As blood is a scarce resource, efforts to distribute it equitably to all patients who would benefit are of paramount importance. In this editorial we discuss recent data and various aspects important in developing and implementing tools that assist with determining futility in massive transfusion.

A Case of Aggressive Resuscitation and Timely Surgical Intervention to Reverse Severe Acidosis After Multiple Gunshot Wounds to the Chest, Abdomen, and Left Shoulder With a Bullet Fragment Retained in the Heart

The lethal triad of coagulopathy, hypothermia, and acidosis is a well-known cause of severe deterioration and poor prognosis in trauma patients. The presence of this triad complicates the surgical management of a patient suffering from penetrating injury and hemorrhage. Here, we report the case and management of a 44-year-old man with multiple high-caliber gunshot wound (GSW) injuries who became severely acidotic (pH <6.8) with hemorrhagic shock in the setting of massive hemorrhage due to penetrating chest and abdominal trauma. The patient sustained one high-caliber GSW to the left upper quadrant of the abdomen, one high-caliber GSW to the left periumbilical region of the abdomen, one high caliber GSW to the fourth intercostal space of the left chest just medial to the midclavicular line with an expanding hematoma, and one high-caliber GSW to the left shoulder with a floating left shoulder. He arrived at the Emergency Department conscious with a stable pulse but quickly became hemodynamically unstable. He required a thoracotomy and exploratory laparotomy in addition to a massive transfusion protocol. This case demonstrates the reversal of a severely acidotic patient due to massive hemorrhage to a blood pH within normal limits using damage control resuscitation surgery and massive transfusion protocols. The patient has since been discharged home in a stable condition with minimal long-term sequelae.

Comparison of base excess, lactate and pH predicting 72-h mortality of multiple trauma

Objective

To compare the predictive values of base excess (BE), lactate and pH of admission arterial blood gas for 72-h mortality in patients with multiple trauma.

Methods

This was a secondary analysis based on a publicly shared trauma dataset from the Dryad database, which provided the clinical data of 3669 multiple trauma patients with ISS > = 16. The records of BE, lactate, pH and 72-h prognosis data without missing values were selected from this dataset and 2441 individuals were enrolled in the study. Logistic regression model was performed to calculate the odds ratios (ORs) of variables. Area under the curve (AUC) of receiver operating curve (ROC) was utilized to evaluate the predictive value of predictors for 72 h in-hospital mortality. Pairwise comparison of AUCs was performed using the Delong’s test.

Results

The statistically significant correlations were observed between BE and lactate (r = − 0.5861, p < 0.05), lactate and pH (r = − 0.5039, p < 0.05), and BE and pH (r = − 0.7433, p < 0.05). The adjusted ORs of BE, lactate and pH for 72-h mortality with the adjustment for factors including gender, age, ISS category were 0.872 (95%CI: 0.854–0.890), 1.353 (95%CI: 1.296–1.413) and 0.007 (95%CI: 0.003–0.016), respectively. The AUCs of BE, lactate and pH were 0.693 (95%CI: 0.675–0.712), 0.715 (95%CI: 0.697–0.733), 0.670 (95%CI: 0.651–0.689), respectively.

Conclusions

There are significant correlations between BE, lactate and pH of the admission blood gas, all of them are independent predictors of 72-h mortality for multiple trauma. Lactate may have the best predictive value, followed by BE, and finally pH.

Successful Outcomes of Critically Ill Patients with Extreme Metabolic Acidosis Treated with Structured Approach: Case Series

INTRODUCTION

Hydrogen ion concentration which is expressed as pH value is in human blood maintained in narrow physiological range (7.36-7.44 in arterial blood). This range is crucial for normal functioning of most biochemical reactions. Extreme acidosis with pH < 6.8 is incompatible with life, unless pathophysiologic process is rapidly reversed. Timely, standardized, and structured approach to assessment and management of extreme critical illness is essential to maximize the chances of patient's survival.

CASES

We present a series of 3 critically ill patients admitted to Medical intensive care unit (MICU) diagnosed with extreme metabolic acidosis (pH ⩽ 6.8). Each patient was treated using Checklist for Early Recognition and Treatment of Acute Illness and INjury (CERTAIN) which is a standard decision support tool in our MICU. Causes of extreme metabolic acidosis included hemorrhagic shock, sepsis, and acute renal failure and diabetic ketoacidosis. Rapid assessment, prompt resuscitation (IV fluids, vasopressors, mechanical ventilation, and renal replacement), and application of specific causal treatment led to positive outcomes in all 3 patients.

DISCUSSION

Medical physiology textbooks set the lower limit of pH value at which life is possible to 6.8. However, examples from clinical practice show that if adequate resuscitation measures are taken early in the acute phase of the disease, the biochemical cascade of reactions that are considered irreversible (at pH ⩽ 6.8) may be reversed after all.

CONCLUSION

Critical care approach to extreme metabolic acidosis is a prime example of applied clinical physiology where basic science and clinical practice connect. With these case series we show that timely and structured approach to critical illness shifts the boundaries of reversibility for some of the most severe physiologic derangements.

Assessing predictors of futility in patients receiving massive transfusions

BACKGROUND

Massive transfusions are associated with a high mortality rate, but there is little evidence indicating when such efforts are futile. The purpose of this study was to identify clinical variables that could be used as futility indicators in massively transfused patients.

METHODS

We retrospectively analyzed 138 adult surgical patients at our institution receiving a massive transfusion (2016-2019). Peak lactate and nadir pH within 24 h of massive transfusion initiation, along with other clinical variables, were assessed as predictors of the primary outcome, in-hospital mortality.

RESULTS

The overall rate of in-hospital mortality among our patient population was 52.9% (n = 73). Increasing lactate and decreasing pH were associated with greater mortality among massively transfused patients. Mortality rates were ~2-fold higher for patients in the highest lactate category (≥10.0 mmol/L: 25 of 37; 67.6%) compared to the lowest category (0.0-4.9 mmol/L: 17 of 48; 35.4%) (p = .005), and ~2.5-fold higher for patients in the lowest pH category (<7.00: 8 of 9; 88.9%) compared to the highest category (≥7.40: 8 of 23; 34.7%) (p = .016). Increasing age was also associated with higher mortality (≥65 years: 24 of 33; 72.7%) when compared to younger patients (18-64 years: 49 of 105; 46.7%) (p = .010).

CONCLUSIONS

Peak lactate ≥10.0 mmol/L, nadir pH <7.00, and age ≥65 years were significantly associated with higher rates of in-hospital mortality among massively transfused patients. Incorporating these clinical parameters into a futility index for massive transfusions will be useful in situations where blood products are scarce and/or mortality may be unavoidable.

Characterization of Acidosis in Trauma Patient

Background

Recent data suggest that acidosis alone is not a good predictor of mortality in trauma patients. Little data are currently available regarding factors associated with survival in trauma patients presenting with acidosis.

Aims

The aims were to characterize the outcomes of trauma patients presenting with acidosis and to identify modifiable risk factors associated with mortality in these patients.

Settings and Design

This is a retrospective observational study of University of Arkansas for Medical Sciences (UAMS) trauma patients between November 23, 2013, and May 21, 2017.

Methods

Data were collected from the UAMS trauma registry. The primary outcome was hospital mortality. Analyses were performed using t-test and Pearson's Chi-squared test. Simple and multiple logistic regressions were performed to determine crude and adjusted odds ratios.

Results

There were 532 patients identified and 64.7% were acidotic (pH < 7.35) on presentation: 75.9% pH 7.2-7.35; 18.5% pH 7.0-7.2; and 5.6% pH ≤ 7.0. The total hospital mortality was 23.7%. Nonsurvivors were older and more acidotic, with a base deficit >-8, Glasgow Coma Scale (GCS) ≤ 8, systolic blood pressure ≤ 90, International Normalized Ratio (INR) >1.6, and Injury Severity Score (ISS) >15. Mortality was significantly higher with a pH ≤ 7.2 but mortality with a pH 7.2-7.35 was comparable to pH > 7.35. In the adjusted model, pH ≤ 7.0, pH 7.0-7.2, INR > 1.6, GCS ≤ 8, and ISS > 15 were associated with increased mortality. For patients with a pH ≤ 7.2, only INR was associated with increase in mortality.

Conclusions

A pH ≤ 7.2 is associated with increased mortality. For patients in this range, only the presence of coagulopathy is associated with increased mortality. A pH > 7.2 may be an appropriate treatment goal for acidosis. Further work is needed to identify and target potentially modifiable factors in patients with acidosis such as coagulopathy.