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

Lactate clearance as a useful biomarker for the prediction of all-cause mortality in critically ill patients: a systematic review study protocol

INTRODUCTION

Arterial lactate is a reflection of balance between lactate production and clearance. Accumulating lactate may be a marker of global hypoxia or hypoperfusion. Lactate clearance is the reduction of lactate concentrations with interventional strategies, and it has been associated with increased risk of death in critically ill patients. However, conflicting results exist, which mandates a systematic review to clarify the association between lactate clearance and clinical outcome.

METHODS AND ANALYSIS

Critically ill adult patients will be included in our analysis. This population will include heterogeneous study participants, including patients with sepsis or severe sepsis, trauma, surgical intensive care unit (ICU) patients, and so on. We will search four databases including EBSCO, PubMed, Scopus and ISI Web of knowledge from inception to February 2014. There will be no language restrictions in the electronic search for studies. Newcastle Ottawa Scale for cohort study will be employed to assess the reporting quality of included original studies. We will report pooled relative risk of death for those with lactate clearance and those without. The diagnostic performance of lactate clearance in predicting mortality will be explored by using the hierarchical summary receiver operating characteristic model.

ETHICS AND DISSEMINATION

The protocol for the systematic review has been registered in PROSPERO. The study will be disseminated electronically and in print. It will also be presented to conferences related to critical care medicine.

TRIAL REGISTRATION NUMBER

CRD42013006511.

Timing of vasopressor initiation and mortality in septic shock: a cohort study

Introduction

Despite recent advances in the management of septic shock, mortality remains unacceptably high. Earlier initiation of key therapies including appropriate antimicrobials and fluid resuscitation appears to reduce the mortality in this condition. This study examined whether early initiation of vasopressor therapy is associated with improved survival in fluid therapy-refractory septic shock.

Methods

Utilizing a well-established database, relevant information including duration of time to vasopressor administration following the initial documentation of recurrent/persistent hypotension associated with septic shock was assessed in 8,670 adult patients from 28 ICUs in Canada, the United States of America, and Saudi Arabia. The primary endpoint was survival to hospital discharge. Secondary endpoints were length of ICU and hospital stay as well as duration of ventilator support and vasopressor dependence. Analysis involved multivariate linear and logistic regression analysis.

Results

In total, 8,640 patients met the definition of septic shock with time of vasopressor/inotropic initiation documented. Of these, 6,514 were suitable for analysis. The overall unadjusted hospital mortality rate was 53%. Independent mortality correlates included liver failure (odds ratio (OR) 3.46, 95% confidence interval (CI), 2.67 to 4.48), metastatic cancer (OR 1.63, CI, 1.32 to 2.01), AIDS (OR 1.91, CI, 1.29 to 2.49), hematologic malignancy (OR 1.88, CI, 1.46 to 2.41), neutropenia (OR 1.78, CI, 1.27 to 2.49) and chronic hypertension (OR 0.62 CI, 0.52 to 0.73). Delay of initiation of appropriate antimicrobial therapy (OR 1.07/hr, CI, 1.06 to 1.08), age (OR 1.03/yr, CI, 1.02 to 1.03), and Acute Physiology and Chronic Health Evaluation (APACHE) II Score (OR 1.11/point, CI, 1.10 to 1.12) were also found to be significant independent correlates of mortality. After adjustment, only a weak correlation between vasopressor delay and hospital mortality was found (adjusted OR 1.02/hr, 95% CI 1.01 to 1.03, P <0.001). This weak effect was entirely driven by the group of patients with the longest delays (>14.1 hours). There was no significant relationship of vasopressor initiation delay to duration of vasopressor therapy (P = 0.313) and only a trend to longer duration of ventilator support (P = 0.055) among survivors.

Conclusion

Marked delays in initiation of vasopressor/inotropic therapy are associated with a small increase in mortality risk in patients with septic shock.

Prevention of tissue hypoperfusion in the trauma patient: initial management

This article outlines the challenges of identification and management of tissue hypoperfusion as a consequence of haemorrhagic shock in civilian polytrauma cases. It also describes damage resuscitation, but does not cover specific trauma cases such as pregnancy, burns, head injuries, children and elderly trauma.

Rapid Emergency Medicine Score (REMS) in the trauma population: a retrospective study

OBJECTIVE

Rapid Emergency Medicine Score (REMS) is an attenuated version of the Acute Physiology and Chronic Health Evaluation (APACHE) II score and has utility in predicting mortality in non-surgical patients, but has yet to be tested among the trauma population. The objective was to evaluate REMS as a risk stratification tool for predicting in-hospital mortality in traumatically injured patients and to compare REMS accuracy in predicting mortality to existing trauma scores, including the Revised Trauma Score (RTS), Injury Severity Score (ISS) and Shock Index (SI).

DESIGN AND SETTING

Retrospective chart review of the trauma registry from an urban academic American College of Surgeons (ACS) level 1 trauma centre.

PARTICIPANTS

3680 patients with trauma aged 14 years and older admitted to the hospital over a 4-year period. Patients transferred from other hospitals were excluded from the study as were those who suffered from burn or drowning-related injuries. Patients with vital sign documentation insufficient to calculate an REMS score were also excluded.

PRIMARY OUTCOME MEASURES

The predictive ability of REMS was evaluated using ORs for in-hospital mortality. The discriminate power of REMS, RTS, ISS and SI was compared using the area under the receiver operating characteristic curve.

RESULTS

Higher REMS was associated with increased mortality (p<0.0001). An increase of 1 point in the 26-point REMS scale was associated with an OR of 1.51 for in-hospital death (95% CI 1.45 to 1.58). REMS (area under the curve (AUC) 0.91±0.02) was found to be similar to RTS (AUC 0.89±0.04) and superior to ISS (AUC 0.87±0.01) and SI (AUC 0.55±0.31) in predicting in-hospital mortality.

CONCLUSIONS

In the trauma population, REMS appears to be a simple, accurate predictor of in-hospital mortality. While REMS performed similarly to RTS in predicting mortality, it did outperform other traditionally used trauma scoring systems, specifically ISS and SI.

Use of point-of-care lactate in the prehospital aeromedical environment

INTRODUCTION

Lactate measurement has been used to identify critical medical illness and initiate early treatment strategies. The prehospital environment offers an opportunity for very early identification of critical illness and commencement of care.

HYPOTHESIS

The investigators hypothesized that point-of-care lactate measurement in the prehospital aeromedical environment would: (1) identify medical patients with high mortality; (2) influence fluid, transfusion, and intubation; and (3) increase early central venous catheter (CVC) placement.

METHODS

Critically ill, medical, nontrauma patients who were transported from September 2007 through February 2009 by University of Massachusetts (UMass) Memorial LifeFlight, a university-based emergency medical helicopter service, were eligible for enrollment. Patients were prospectively randomized to receive a fingerstick whole-blood lactate measurement on an alternate-day schedule. Flight crews were not blinded to results. Flight crews were asked to inform the receiving attending physician of the results. The primary endpoint was the ability of a high, prehospital lactate value [> 4 millimoles per liter (mmol/L)] to identify mortality. Secondary endpoints included differences in post-transport fluid, transfusion, and intubation, and decrease in time to central venous catheter (CVC) placement. Categorical variables were compared between groups by Fisher's Exact Test, and continuous variables were compared by t-test.

RESULTS

Patients (N = 59) were well matched for age, gender, and acuity. In the lactate cohort (n = 20), mean lactate was 7 mmol/L [Standard error of the mean, SEM = 1]. Initial analysis revealed that prehospital lactate levels of ≥ 4 mmol/L did show a trend toward higher mortality with an odds ratio of 2.1 (95% CI, 0.3-13.8). Secondary endpoints did not show a statistically significant change in management between the lactate and non lactate groups. There was a trend toward decreased time to post-transport CVC in the non lactate faction.

CONCLUSION

Prehospital aeromedical point-of-care lactate measurement levels ≥ 4 mmol/L may help stratify mortality. Further investigation is needed, as this is a small, limited study. The initial analysis did not find a significant change in post-transport management.

Etiology and therapeutic approach to elevated lactate levels

Lactate levels are commonly evaluated in acutely ill patients. Although most often used in the context of evaluating shock, lactate levels can be elevated for many reasons. While tissue hypoperfusion may be the most common cause of elevation, many other etiologies or contributing factors exist. Clinicians need to be aware of the many potential causes of lactate level elevation as the clinical and prognostic importance of an elevated lactate level varies widely by disease state. Moreover, specific therapy may need to be tailored to the underlying cause of elevation. The present review is based on a comprehensive PubMed search between the dates of January 1, 1960, to April 30, 2013, using the search term lactate or lactic acidosis combined with known associations, such as shock, sepsis, cardiac arrest, trauma, seizure, ischemia, diabetic ketoacidosis, thiamine, malignancy, liver, toxins, overdose, and medication. We provide an overview of the pathogenesis of lactate level elevation followed by an in-depth look at the varied etiologies, including medication-related causes. The strengths and weaknesses of lactate as a diagnostic/prognostic tool and its potential use as a clinical end point of resuscitation are discussed. The review ends with some general recommendations on the management of patients with elevated lactate levels.

Changes in blood lactate levels after major elective abdominal surgery and the association with outcomes: a prospective observational study

BACKGROUND

Prolonged elevated blood lactate levels strongly correlate with poor outcomes in a variety of critically ill patients. We hypothesized that the dynamic postoperative changes in blood lactate levels during the first 24 h were significantly associated with postoperative morbidity and mortality in patients undergoing elective major abdominal surgery.

MATERIALS AND METHODS

We performed a single-center prospective observational study of 114 consecutive patients undergoing elective major abdominal surgery from September 2009 to December 2010. Blood lactate was determined postoperatively at 6 h intervals during the first 24 h. In-hospital complications and deaths occurring within 30 d of enrollment were included in the data analysis.

RESULTS

A total of 88 postoperative complications were recorded in 51 patients (44.7%). There was a significant difference in blood lactate levels among patients with no, minor, and major complications (ANOVA, Groups, P < 0.001; time, P < 0.001; groups × time interaction, P = 0.014). The accuracy of lactate levels to predict both overall and major complications increased postoperatively from 0 h to 24 h. Using a multivariate analysis, the time-weighted average lactate was independently predictive of both overall (OR 7.108, 95% CI 2.271-22.249, P = 0.001) and major (OR 3.277, 95% CI 1.363-7.877, P = 0.008) postoperative complications, and lactate clearance at 0-24 h (OR 0.217, CI 0.077-0.616, P = 0.004) was independently predictive of major postoperative complications. The optimal time-weighted average lactate cutoff value for complication prediction was 1.46 mmol/L; below this level, both overall and major complication rates were significantly reduced, which was true even after adjusting for potential confounding factors.

CONCLUSIONS

The dynamic changes in blood lactate levels during the first 24 postoperative h were significantly associated with complications after major elective abdominal surgery. This result warrants a "golden hour and silver day" perspective of early resuscitation in this patient cohort.

Damage control - trauma care in the first hour and beyond: a clinical review of relevant developments in the field of trauma care

INTRODUCTION

Trauma provision in the UK is a topic of interest. Regional trauma networks and centres are evolving and research is blossoming, but what bearing does all this have on the care that is delivered to the individual patient? This article aims to provide an overview of key research concepts in the field of trauma care, to guide the clinician in decision making in the management of major trauma.

METHODS

The Ovid MEDLINE(®), EMBASE™ and PubMed databases were used to search for relevant articles on haemorrhage control, damage control resuscitation and its exceptions, massive transfusion protocols, prevention and correction of coagulopathy, acidosis and hypothermia, and damage-control surgery.

FINDINGS

A wealth of research is available and a broad range has been reviewed to summarise significant developments in trauma care. Research has been categorised into disciplines and it is hoped that by considering each, a tailored management plan for the individual trauma patient will evolve, potentially improving patient outcome.

Even mild hyperlactatemia is associated with increased mortality in critically ill patients

Introduction

The clinical significance of elevation of lactate levels within the reference range is not well studied. The objective of this study was to determine the best cutoff threshold for serum lactate within the reference range (0.01 to 2.00 mM) that best discriminated between survivors and nonsurvivors of critical illness and to examine the association between relative hyperlactatemia (lactate above the identified threshold) and mortality.

Methods

This was a retrospective cohort study of adult patients admitted to the medical-surgical intensive care unit (ICU) of a tertiary care academic center. Youden index was calculated to identify the best lactate cutoff threshold that discriminated between survivors and nonsurvivors. Patients with lactate above the identified threshold were defined as having relative hyperlactatemia. Multivariate logistic regression, adjusting for baseline variables, was performed to determine the relationship between the above two ranges of lactate levels and mortality. In addition, a test of interaction was performed to assess the effect of selected subgroups on the association between relative hyperlactatemia and hospital mortality.

Results

During the study period, 2,157 patients were included in the study with mean lactate of 1.3 ± 0.4 mM, age of 55.1 ± 20.3 years, and acute physiology and chronic health evaluation (APACHE) II score of 22.1 ± 8.2. Vasopressors were required in 42.4%. Lactate of 1.35 mM was found to be the best cutoff threshold for the whole cohort. Relative hyperlactatemia was associated with increased hospital mortality (adjusted odds ratio (aOR), 1.60, 95% confidence interval (CI) 1.29 to 1.98), and ICU mortality (aOR, 1.66; 95% CI, 1.26 to 2.17) compared with a lactate level of 0.01 to 1.35 mM. This association was consistent among all examined subgroups.

Conclusions

Relative hyperlactatemia (lactate of 1.36 to 2.00 mM) within the first 24 hours of ICU admission is an independent predictor of hospital and ICU mortality in critically ill patients.

Perfusion, hypoperfusion, and ischemia processes: the effect on bodily function

Adequate perfusion is requisite for normal body function. Should perfusion be disrupted, a cascade of events may result that can lead to disruption of function and potentially cell, tissue, organ, and ultimately organism death. Contrary to logic, reperfusion as a modality of treatment is not without issues in the form of reperfusion injury.

Capillary lactic acid validation in an ED

INTRODUCTION

One of the most used methods to evaluate patients with a high risk not responding to clinical treatment is the measurement of blood levels of lactic acid (LA). The objective of this study was to compare the sensitivity and specificity of an LA test for capillary and venous blood with LA test for arterial blood in a population of patients with tissue hypoperfusion and to evaluate the time needed for each test.

MATERIALS AND METHODS

The following factors were evaluated: the performance of venous and capillary LA in relation to arterial LA, and the time needed to elicit each method from patient admission to mortality according to initial LA.

RESULTS

Seventy-nine patients with a median age of 58 years were admitted. The area under the curve for capillary LA was 82% (95% confidence interval [CI], 73-91). The best cutoff point was 2.35, with a sensitivity of 81% (95% CI, 65-90) and a specificity of 70% (95% CI, 53-83). The average time from patient admission until arterial, venous, and capillary LA values were obtained was 112, 117, and 77 minutes, respectively. The patients who died within 3, 30, and 60 days showed an average arterial LA of 5.9, 1.9, and 2.2, respectively.

CONCLUSION

The utilization of capillary and venous LA is an effective method of evaluation and risk stratification for patients with different degrees of tissue hypoperfusion. The time needed to elicit capillary LA proved much faster with respect to arterial and venous LA.

Association between a geriatric trauma resuscitation protocol using venous lactate measurements and early trauma surgeon involvement and mortality risk

OBJECTIVES

To investigate whether implementing a geriatric resuscitation protocol that uses lactate-guided therapy with early trauma surgeon involvement is associated with lower mortality through the early recognition of occult hypoperfusion (OH).

DESIGN

Prospective cohort study.

SETTING

Level I trauma center.

PARTICIPANTS

All hemodynamically stable individuals with blunt trauma aged 65 and older admitted to the Level I trauma center from October 1, 2008, through December 31, 2011 (n = 1,998).

MEASUREMENTS

Mortality over time (according to quarter) was analyzed using an adjusted logarithmic regression model stratified according to the presence of OH. OH was defined as lactate of 2.5 mM or greater.

RESULTS

Overall mortality was 3.9% (n = 78). Admission venous lactate was collected in 73.5% of participants, of whom 20.5% had OH (n = 301). In participants with OH, a significant decrease in mortality was observed over time (adjusted coefficient of determination (R(2) ) = 0.66, P = .002). A smaller yet significant decrease in mortality rates in participants with normal perfusion status was also observed (adjusted R(2) = 0.55, P = .01).

CONCLUSION

Early identification and treatment of OH in elderly adults with trauma using venous lactate-guided therapy coupled with early trauma surgeon involvement was associated with significantly lower mortality. A protocol that uses lactate-guided therapy with early trauma surgeon involvement should be followed to improve the care of elderly adults with trauma.

Venous and arterial base deficits: do these agree in occult shock and in the elderly? A Bland-Altman analysis

BACKGROUND

Trauma centers are increasingly advocating the replacement of arterial blood gas measurements with venous blood gas measurements for simplification of base deficit (BD) determination. These values have never been demonstrated to agree in important trauma populations, such as for patients in occult shock (OS) or the elderly. The goal of this study was to investigate the level of agreement between venous and arterial BDs from blood gases in critically ill or injured patients, specifically in OS and the elderly.

METHODS

This is a retrospective, consecutive, cohort study using matched pairs of venous and arterial blood gases from patients admitted to the Trauma and Neurosurgery Intensive Care Unit in a Level I trauma center in Toronto, Ontario, Canada. Agreement between near simultaneous arterial and venous BD was calculated using the Bland-Altman method. McNemar's test was used for differences in BDs in the presence or absence of OS and in elderly patients.

RESULTS

BDs for 466 arterial and venous samples from 72 patients were compared pairwise. There was no significant difference between samples (p = 0.88). Ninety-eight percent of samples were within 3.0 mmol/L of each other. No significant differences were detected between venous and arterial BD in the presence of OS or in the elderly (p = 0.72 and p = 0.25, respectively).

CONCLUSION

Arterial and venous BDs agree, including in the presence of OS and in the elderly. Consideration may be given to venous sampling both in the intensive care unit or in other areas of care, such as the trauma bay.

LEVEL OF EVIDENCE

Diagnostic study, level III.

Prehospital neurologic deterioration is independent predictor of outcome in traumatic brain injury: analysis from National Trauma Data Bank

BACKGROUND

The prevalence and impact of prehospital neurologic deterioration (PhND) in patients with traumatic brain injury (TBI) have not been investigated. We aimed to determine the prevalence of PhND during emergency medical service (EMS) transportation among patients with TBI and its impact on patient's outcome.

METHODS

We used the National Trauma Data Bank, using data files from 2009 to 2010 to identify patients with TBI through International Classification of Diseases, Ninth Revision, Clinical Modification diagnosis codes. The initial Glasgow Coma Scale (GCS) score ascertained at the scene by EMS was compared with the subsequent GCS score evaluation in the emergency department (ED) to identify neurologic deterioration (defined as a decrease in GCS of ≥2 points). Patients' demographics, initial injury severity score (ISS), admission GCS score, and hospital outcome were compared between patients with PhND and patients without neurologic deterioration.

RESULTS

A total of 257 127 patients with TBI were identified. Among patients with TBI, 22 254 patients had PhND, which comprised 9% of all patients with TBI. The mean of GCS score decrease during EMS transport was 5 points (±3). Patients without PhND tended to have higher GCS recorded by EMS (median, 15 vs 12; P < .0001). Patients with TBI who had PhND had significantly higher hospital length of stay and intensive care unit days after adjusting for baseline characteristics and EMS GCS score, EMS transport time, type of injury, presence of intracranial hemorrhages, and ED ISS (P < .0001). These patients had higher rate of in-hospital mortality after adjusting for the same variables (odds ratio, 2.30; 95% confidence interval, 2.18-2.41).

CONCLUSION

Prehospital neurologic deterioration occurs in 9% of patients with TBI. It is more prevalent in men and associated with lower EMS GCS level and higher ED ISS. Prehospital neurologic deterioration is an independent predictor of worse hospital outcome and higher resource use in patients with TBI.

Continuous neuromuscular blockade is associated with decreased mortality in post-cardiac arrest patients

AIM

Neuromuscular blockade may improve outcomes in patients with acute respiratory distress syndrome. In post-cardiac arrest patients receiving therapeutic hypothermia, neuromuscular blockade is often used to prevent shivering. Our objective was to determine whether neuromuscular blockade is associated with improved outcomes after out-of-hospital cardiac arrest.

METHODS

A post hoc analysis of a prospective observational study of comatose adult (>18 years) out-of-hospital cardiac arrest at 4 tertiary cardiac arrest centers. The primary exposure of interest was neuromuscular blockade for 24h following return of spontaneous circulation and primary outcomes were in-hospital survival and functional status at hospital discharge. Secondary outcomes were evolution of oxygenation (PaO2:FiO2), and change in lactate. We tested the primary outcomes of in-hospital survival and neurologically intact survival with multivariable logistic regression. Secondary outcomes were tested with multivariable linear mixed-models.

RESULTS

A total of 111 patients were analyzed. In patients with 24h of sustained neuromuscular blockade, the crude survival rate was 14/18 (78%) compared to 38/93 (41%) in patients without sustained neuromuscular blockade (p=0.004). After multivariable adjustment, neuromuscular blockade was associated with survival (adjusted OR: 7.23, 95% CI: 1.56-33.38). There was a trend toward improved functional outcome with neuromuscular blockade (50% versus 28%; p=0.07). Sustained neuromuscular blockade was associated with improved lactate clearance (adjusted p=0.01).

CONCLUSIONS

We found that early neuromuscular blockade for a 24-h period is associated with an increased probability of survival. Secondarily, we found that early, sustained neuromuscular blockade is associated with improved lactate clearance.

Diagnostic accuracy of a single point-of-care prehospital serum lactate for predicting outcomes in pediatric trauma patients

BACKGROUND

Preliminary evidence suggests that a single prehospital lactate level (pLA) improves prediction of morbidity and mortality in adult trauma patients independent of vital signs. However, the value of pLA for pediatric trauma patients is unknown. Our objective was to determine whether pLA is associated with the need for critical care in pediatric trauma patients.

METHODS

We conducted a cohort study of 217 patients transported by helicopter to a level I pediatric trauma center over 24 months. The primary outcome was the need for predefined critical care measures. Covariates included vital signs and Glasgow Coma Scale (GCS) scores documented by prehospital providers.

RESULTS

Forty-one subjects required critical care. Abnormal prehospital vital signs were not associated with need for critical care. Overall, median pLA level for patients who required critical care was 2.1 mmol/L (interquartile range [IQR], 1.6-2.7 mmol/L) versus 1.7 mmol/L (IQR, 1.2-2.2 mmol/L) for those who did not (P = 0.01). In addition, there were 85 subjects who had normal vital signs and a normal GCS during transport. Of these, 11 (13%) required critical care. In the subset of patients with normal prehospital vital signs and GCS, median pLA level for patients who required critical care was 2.6 mmol/L (IQR, 1.8-2.6 mmol/L) versus 1.7 mmol/L (IQR, 1-2.1 mmol/L) for those who did not (P = 0.01).

CONCLUSIONS

Prehospital lactate level was higher in pediatric trauma patients who required critical care, including those who had normal prehospital vital signs and GCS. In this cohort, lactate was an early identifier of children with severe traumatic injuries.

Serum lactate is a prognostic indicator in patients with hip fracture

BACKGROUND AND PURPOSE

Serum lactate has been shown to be an indicator of adverse clinical outcomes in patients admitted secondary to general trauma or sepsis. We retrospectively investigated whether admission serum venous lactate can predict in-hospital mortality in patients with hip fractures.

METHOD AND RESULTS

Over a 38-month period the admission venous lactate of 807 patients with hip fractures was collated. Mean age was 82 years. The overall in-hospital mortality for this cohort was 9.4%. Mortality was not influenced by the fracture pattern or the type of surgery - be it internal fixation or arthroplasty (p = 0.7). A critical threshold of 3 mmol/L with respect to the influence of venous lactate level on mortality was identified. Mortality rate in those with a lactate level of less than 3 mmol/L was 8.6% and 14.2% for those whose level was 3 mmol/L or greater. A 1 mmol/L increase in venous lactate was associated with a 1.2 (1.02-1.41) increased risk of in-hospital mortality. Patients with a venous lactate of 3 mmol/L or higher had twice the odds of death in hospital compared to matched individuals. There was no statistically significant difference in ASA distribution between those with a lactate of less than or greater than 3 mmol/L.

CONCLUSIONS

Patients with an elevated venous lactate following hip trauma should be identified as being at increased risk of death and may benefit from targeted medical therapy.

Admission base excess as a predictor of transfusion requirement and mortality in dogs with blunt trauma: 52 cases (2007-2009)

OBJECTIVE

To evaluate the ability of admission base excess (ABE) to predict blood transfusion requirement and mortality in dogs following blunt trauma.

DESIGN

Retrospective study 2007-2009.

SETTING

University Veterinary Teaching Hospital.

ANIMALS

Fifty-two dogs admitted to the intensive care unit for treatment following blunt trauma.

MEASUREMENTS AND MAIN RESULTS

Animals requiring red blood cell transfusion (N = 8) had significantly lower ABE than those not requiring transfusion (N = 44; median base excess [BE] = -8.4 versus -4.7, P = .0034), while there was no difference in admission packed cell volume (PCV) or age. Animals that died or were euthanized due to progression of signs (N = 5) had lower median ABE than those that survived (N = 47; median BE = -7.3 versus -4.9, P = 0.018). Admission PCV and age were not significantly different between survivors and nonsurvivors. Receiver operator characteristic curve analysis showed an ABE cutoff of -6.6 was 88% sensitive and 73% specific for transfusion requirement (P < 0.001), and a cutoff of -7.3 was 81% sensitive and 80% specific for survival (P < 0.001). Multivariate logistic regression analysis demonstrated that ABE was a predictor of transfusion requirement that was independent of overall severity of injury as measured by the Animal Triage Trauma (ATT) score, but a similar analysis showed that only ATT was an independent predictor of survival.

CONCLUSIONS

The ABE in dogs with blunt trauma was a predictor of mortality and blood transfusion requirement within 24 hours.

Lactic acidosis is associated with multiple organ failure and need for ventilator support in patients with severe hemorrhage from trauma

PURPOSE

Lactate is a biomarker for hypoperfusion and subsequent resuscitation in trauma. It is also a predictor of mortality, but few studies have correlated lactate levels with relevant morbidities after trauma.

METHODS

A retrospective review was performed of severely injured trauma patients entered into the Trauma Registry of the German Society for Trauma Surgery (TR-DGU) between 2002 and 2008. Adults requiring intensive care were categorized into two groups: lactate and no lactate. The lactate group had three subgroups: normal, elevated, and high lactate. Mean multiple organ failure (MOF) rates and composite endpoint of time (days) to complete organ failure resolution (CTCOFR) for 14 and 21 days and ventilator-free days (VFD) were compared, as well as other endpoints.

RESULTS

We analyzed 2,949 patients, of which 1,199 had lactate measurements. The percentage of patients with MOF increased in each higher lactate subgroup (p < 0.001), as did the mean CTCOFR14 and CTCOFR21 scores (p < 0.001 and < 0.001, respectively). Conversely, the mean VFD decreased in each higher lactate subgroup (p < 0.001). Thus, patients in the elevated and high lactate subgroups had greater MOF rates; required more days, on average, to resolve organ failure; and required more days of ventilator support than patients in the normal lactate subgroup.

CONCLUSION

Elevated blood lactate levels from trauma were closely correlated with worse outcomes. Thus, lactate shows promise as a biomarker for resuscitation as well as a predictor of mortality. Furthermore, this study supports its use in critical care trials as an outcome measure.

Splenic Doppler resistive index for early detection of occult hemorrhagic shock after polytrauma in adult patients

The objective of this study was to evaluate whether direct assessment of splenic circulation by splenic Doppler resistive index (Doppler RI) is a clinically useful noninvasive method for an early detection of occult hemorrhagic shock after polytrauma in adult patients. Splenic Doppler RI was measured in 49 hemodynamically stable adult patients admitted to the emergency department because of polytrauma. Renal Doppler RI was also determined in 20 patients. Spleen size, Injury Severity Score, systolic blood pressure, heart rate, blood lactate, standard base excess, pH, hemoglobin, and inferior vena cava diameter values were recorded at admission and at 24 h. Patients were grouped according to whether signs of hemorrhagic shock did (n = 22) or did not (n = 27) occur within the first 24 h from admission. Patients who developed hemorrhagic shock had significantly higher splenic and renal Doppler RI, higher Injury Severity Score, and lower standard base excess at admission. By multivariate logistic regression, splenic Doppler RI resulted to be a predictor of hemorrhagic shock development within the first 24 h from admission. Splenic Doppler RI may represent a clinically useful noninvasive method for early detection of occult hemorrhagic shock and persistent occult hypoperfusion after polytrauma in adult patients.

A retrospective analysis of geriatric trauma patients: venous lactate is a better predictor of mortality than traditional vital signs

BACKGROUND

Traditional vital signs (TVS), including systolic blood pressure (SBP), heart rate (HR) and their composite, the shock index, may be poor prognostic indicators in geriatric trauma patients. The purpose of this study is to determine whether lactate predicts mortality better than TVS.

METHODS

We studied a large cohort of trauma patients age ≥ 65 years admitted to a level 1 trauma center from 2009-01-01 - 2011-12-31. We defined abnormal TVS as hypotension (SBP < 90 mm Hg) and/or tachycardia (HR > 120 beats/min), an elevated shock index as HR/SBP ≥ 1, an elevated venous lactate as ≥ 2.5 mM, and occult hypoperfusion as elevated lactate with normal TVS. The association between these variables and in-hospital mortality was compared using Chi-square tests and multivariate logistic regression.

RESULTS

There were 1987 geriatric trauma patients included, with an overall mortality of 4.23% and an incidence of occult hypoperfusion of 20.03%. After adjustment for GCS, ISS, and advanced age, venous lactate significantly predicted mortality (OR: 2.62, p < 0.001), whereas abnormal TVS (OR: 1.71, p = 0.21) and SI ≥ 1 (OR: 1.18, p = 0.78) did not. Mortality was significantly greater in patients with occult hypoperfusion compared to patients with no sign of circulatory hemodynamic instability (10.67% versus 3.67%, p < 0.001), which continued after adjustment (OR: 2.12, p = 0.01).

CONCLUSIONS

Our findings demonstrate that occult hypoperfusion was exceedingly common in geriatric trauma patients, and was associated with a two-fold increased odds of mortality. Venous lactate should be measured for all geriatric trauma patients to improve the identification of hemodynamic instability and optimize resuscitative efforts.

Association of serum lactate and survival outcomes in patients undergoing therapeutic hypothermia after cardiac arrest

INTRODUCTION

Recent studies have suggested that serum lactate may serve as a marker to predict mortality after resuscitation from cardiac arrest (CA). The relationship between serum lactate and CA outcomes requires further characterization, especially among patients treated with therapeutic hypothermia (TH) and aggressive post-arrest care.

METHODS

A retrospective analysis of patients resuscitated from non-traumatic CA at three urban U.S. hospitals was performed using an established internet-based post-arrest registry. Adult (≥ 18 years) patients resuscitated from CA and receiving TH treatment were included. Logistic regression analysis was used to adjust for potential confounders to survival outcomes. Survival to discharge served as the primary endpoint.

RESULTS

A total of 199 post-CA patients treated with TH between 5/2005 and 11/2011 were included in this analysis. The mean age was 56.9 ± 16.5 years, 85/199 (42.7%) patients were female, and survival to discharge was attained in 84/199 (42.2%). While lower initial post-CA serum lactate levels were not associated with increased survival to discharge, subsequent lactate measurements were significantly associated with outcomes (24-h serum lactate levels in survivors vs. non-survivors, 2.7 ± 0.5 vs. 4.2 ± 0.4 mmol/L, p<0.01). Multivariable logistic regression confirmed this relationship with survival to discharge (p<0.01).

CONCLUSION

Lower serum lactate levels at 12h and 24h, but not initially following cardiac arrest, are associated with survival to hospital discharge after resuscitation from CA and TH treatment. Prospective investigation of serum lactate as a potential prognostic tool in CA is needed.

Early fracture stabilisation in the presence of subclinical hypoperfusion

INTRODUCTION

In polytrauma patients with an injury severity score (ISS)>16, early long bone and pelvic fracture fixation within 24h after injury has been shown to be beneficial. In contrast, surgery in the presence of subclinical hypoperfusion (SCH), defined as normal vital signs with a serum lactate≥2.5mmol/L may be detrimental. This study aimed to investigate the effect of fracture fixation in polytrauma patients with SCH.

METHODS

We undertook a database review extracting 88 polytrauma patients with a new injury severity score (NISS)>16 with significant long bone or pelvic fractures (extremity NISS≥9) who underwent surgical fracture stabilisation within 48h of injury. In the group of patients with normal vital signs (mean arterial pressure≥60mmHg and heart rate≤110 beats/min) we compared outcomes between those with a normal preoperative lactate (<2.5mmol/L) and those with a raised lactate (≥2.5mmol/L).

RESULTS

Of the 36 patients with normal preoperative vital signs, 17 had normal lactates (control group) and 19 abnormal lactates (SCH group). There were no significant differences in the method of fixation or theatre time between the groups. The SCH group required more inotropic support in the first 24h post surgery (p=0.02) and had higher sequential organ failure assessment (SOFA) scores on day 3 (p=0.003). Although not reaching mathematical significance those with SCH required on average 10 days longer on mechanical ventilation.

CONCLUSION

Early fracture fixation in patients with SCH as defined by normal vital signs and a lactate≥2.5mmol/L is associated with significant postoperative morbidity. Consideration should be given to delaying surgery in this cohort.

Emergency Department vancomycin use: dosing practices and associated outcomes

BACKGROUND

Emergency Department (ED) dosing of vancomycin and its effect on outcomes has not been examined.

STUDY OBJECTIVE

To describe current vancomycin dosing practices for ED patients, focusing on patient factors associated with administration, dosing accuracy based on patient body weight, and clinical outcomes.

METHODS

Single-center, retrospective cohort study of vancomycin administered in the ED over 18 months in an academic, tertiary care ED. Data were collected on 4656 patients. Data were analyzed using a generalized estimating equations model to account for multiple doses being administered to the same patient.

RESULTS

The ED dose was continued, unchanged, in 2560 admitted patients (83.8%). The correct dose was given 980 times (22.1%), 3143 doses (70.7%) were underdosed, and 318 were overdosed (7.2%). Increasing weight was associated with underdosing (adjusted odds ratio 1.52 per 10 kg body weight, p < 0.001). Patients who received doses of vancomycin > 20 mg/kg had longer hospital length of stay (p = 0.005); were more likely to spend ≥ 3 days in the hospital (odds ratio [OR] 1.49; 95% confidence interval [CI] 1.12-1.98, p = 0.006); and more likely to die (OR 1.88; 95% CI 1.22-2.90, p = 0.004).

CONCLUSION

In this largest study to date examining ED vancomycin dosing, vancomycin was commonly given. Dosing outside the recommended range was frequent, and especially prevalent in patients with a higher body weight. The ED dose of vancomycin was frequently continued as an inpatient, regardless of dosing accuracy. There is significant room for improvement in dosing accuracy and indication. Vancomycin dosing in the ED may also affect clinical outcomes.

Perioperative increase in global blood flow to explicit defined goals and outcomes following surgery

BACKGROUND

Studies have suggested that increasing whole body blood flow and oxygen delivery around the time of surgery reduces mortality, morbidity and the expense of major operations.

OBJECTIVES

To describe the effects of increasing perioperative blood flow using fluids with or without inotropes or vasoactive drugs. Outcomes were mortality, morbidity, resource utilization and health status.

SEARCH METHODS

We searched CENTRAL (The Cochrane Library 2012, Issue 1), MEDLINE (1966 to March 2012) and EMBASE (1982 to March 2012). We manually searched the proceedings of major conferences and personal reference databases up to December 2011. We contacted experts in the field and pharmaceutical companies for published and unpublished data.

SELECTION CRITERIA

We included randomized controlled trials with or without blinding. We included studies involving adult patients (aged 16 years or older) undergoing surgery (patients having a procedure in an operating room). The intervention met the following criteria. 'Perioperative' was defined as starting up to 24 hours before surgery and stopping up to six hours after surgery. 'Targeted to increase global blood flow' was defined by explicit measured goals that were greater than in controls, specifically one or more of cardiac index, oxygen delivery, oxygen consumption, stroke volume (and the respective derived indices), mixed venous oxygen saturation (SVO(2)), oxygen extraction ratio (0(2)ER) or lactate.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted the data. We contacted study authors for additional data. We used Review Manager software.

MAIN RESULTS

We included 31 studies of 5292 participants. There was no difference in mortality: 282/2615 (10.8%) died in the control group and 238/2677 (8.9%) in the treatment group, RR of 0.89 (95% CI 0.76 to 1.05, P = 0.18). However, the results were sensitive to analytical methods and the intervention was better than control when inverse variance or Mantel-Haenszel random-effects models were used, RR of 0.72 (95% CI 0.55 to 0.95, P = 0.02). The results were also sensitive to withdrawal of studies with methodological limitations. The rates of three morbidities were reduced by increasing global blood flow: renal failure, RR of 0.71 (95% CI 0.57 to 0.90); respiratory failure, RR of 0.51 (95% CI 0.28 to 0.93); and wound infections, RR of 0.65 (95% CI 0.51 to 0.84). There were no differences in the rates of nine other morbidities: arrhythmia, pneumonia, sepsis, abdominal infection, urinary tract infection, myocardial infarction, congestive cardiac failure or pulmonary oedema, or venous thrombosis. The number of patients with complications was reduced by the intervention, RR of 0.68 (95% CI 0.58 to 0.80). Hospital length of stay was reduced in the treatment group by a mean of 1.16 days (95% CI 0.43 to 1.89, P = 0.002). There was no difference in critical care length of stay. There were insufficient data to comment on quality of life and cost effectiveness.

AUTHORS' CONCLUSIONS

It remains uncertain whether increasing blood flow using fluids, with or without inotropes or vasoactive drugs, reduces mortality in adults undergoing surgery. The primary analysis in this review (mortality at longest follow-up) showed no difference between the intervention and control, but this result was sensitive to the method of analysis, the withdrawal of studies with methodological limitations, and is dominated by a single large RCT. Overall, for every 100 patients in whom blood flow is increased perioperatively to defined goals, one can expect 13 in 100 patients (from 40/100 to 27/100) to avoid a complication, 2/100 to avoid renal impairment (from 8/100 to 6/100), 5/100 to avoid respiratory failure (from 10/100 to 5/100), and 4/100 to avoid postoperative wound infection (from 10/100 to 6/100). On average, patients receiving the intervention stay in hospital one day less. It is unlikely that the intervention causes harm. The balance of current evidence does not support widespread implementation of this approach to reduce mortality but does suggest that complications and duration of hospital stay are reduced.

The damage control sequence in the elderly: Strategy, complexities, and outcomes

Traditional management in cases of exsanguinating abdominal trauma led to poor outcomes in critically injured patients. Because prolonged operations were not well tolerated due to the severe physiologic derangements, an abbreviated laparotomy began to be used. Patients were then resuscitated in the intensive care unit and brought back to the operating room once their physiology had been normalised. This approach has been termed the damage control sequence. Elderly trauma patients are susceptible to significant injury that may mandate a damage control sequence. For myriad reasons, including pre-existing medical conditions, decreased physiologic reserve, and the emergent nature of their injuries, the application of this management approach in the elderly is fraught with challenges. The purpose of this review is to enumerate the damage control sequence, describe the complexities of its use in the elderly, and discuss associated outcomes in this challenging patient population.

Critical care considerations in the management of the trauma patient following initial resuscitation

Background

Care of the polytrauma patient does not end in the operating room or resuscitation bay. The patient presenting to the intensive care unit following initial resuscitation and damage control surgery may be far from stable with ongoing hemorrhage, resuscitation needs, and injuries still requiring definitive repair. The intensive care physician must understand the respiratory, cardiovascular, metabolic, and immunologic consequences of trauma resuscitation and massive transfusion in order to evaluate and adjust the ongoing resuscitative needs of the patient and address potential complications. In this review, we address ongoing resuscitation in the intensive care unit along with potential complications in the trauma patient after initial resuscitation. Complications such as abdominal compartment syndrome, transfusion related patterns of acute lung injury and metabolic consequences subsequent to post-trauma resuscitation are presented.

Methods

A non-systematic literature search was conducted using PubMed and the Cochrane Database of Systematic Reviews up to May 2012.

Results and conclusion

Polytrauma patients with severe shock from hemorrhage and massive tissue injury present major challenges for management and resuscitation in the intensive care setting. Many of the current recommendations for “damage control resuscitation” including the use of fixed ratios in the treatment of trauma induced coagulopathy remain controversial. A lack of large, randomized, controlled trials leaves most recommendations at the level of consensus, expert opinion. Ongoing trials and improvements in monitoring and resuscitation technologies will further influence how we manage these complex and challenging patients.

Monitoring in the intensive care

In critical care, the monitoring is essential to the daily care of ICU patients, as the optimization of patient's hemodynamic, ventilation, temperature, nutrition, and metabolism is the key to improve patients' survival. Indeed, the decisive endpoint is the supply of oxygen to tissues according to their metabolic needs in order to fuel mitochondrial respiration and, therefore, life. In this sense, both oxygenation and perfusion must be monitored in the implementation of any resuscitation strategy. The emerging concept has been the enhancement of macrocirculation through sequential optimization of heart function and then judging the adequacy of perfusion/oxygenation on specific parameters in a strategy which was aptly coined “goal directed therapy.” On the other hand, the maintenance of normal temperature is critical and should be regularly monitored. Regarding respiratory monitoring of ventilated ICU patients, it includes serial assessment of gas exchange, of respiratory system mechanics, and of patients' readiness for liberation from invasive positive pressure ventilation. Also, the monitoring of nutritional and metabolic care should allow controlling nutrients delivery, adequation between energy needs and delivery, and blood glucose. The present paper will describe the physiological basis, interpretation of, and clinical use of the major endpoints of perfusion/oxygenation adequacy and of temperature, respiratory, nutritional, and metabolic monitorings.

Venous lactate levels can be used to identify patients with poor outcome following community-onset norovirus enteritis

BACKGROUND

Norovirus enteritis (NVE) can be fatal in frail patients. High blood lactate levels indicate hypoperfusion and predict mortality in many infectious diseases. The objective was to determine the frequency and association with mortality of elevated lactate levels in patients with community-onset NVE.

METHODS

A retrospective cohort study was performed. All hospitalized adult patients with community-onset NVE verified by polymerase chain reaction during the period August 2008 to June 2009 were included. Vital signs and venous lactate on arrival, co-morbid conditions, and time of death were registered. The outcome measure was 30-day all-cause mortality.

RESULTS

Eighty-two patients with a median age of 77 y (interquartile range (IQR) 53-86 y) were included, of whom 47 (57%) were female and 49 (60%) had at least 1 major co-morbid condition. Lactate levels were above the upper limit of normal (ULN; 1.6 mmol/l) in 45 patients (55%). The overall 30-day mortality rate was 7% (6/82). Mortality was 18% (5/28) with lactate ≥ 2.4 mmol/l (> 50% above the ULN) on admission compared to 2% (1/54) with lactate < 2.4 mmol/l (p < 0.05). Patients who died had a higher median lactate level compared to survivors: 4.5 (IQR 2.7-7.9) mmol/l vs 1.7 (IQR 1.3-2.5) mmol/l, respectively (p < 0.01). The adjusted odds ratio for death within 30 days for a 1 mmol/l increase in lactate was 2.5 (95% confidence interval 1.003-6.3, p = 0.049).

CONCLUSIONS

We observed a high proportion of patients with elevated lactate levels in community-onset NVE. Lactate elevation could predict mortality. Measurement of blood lactate may be a valuable tool in the clinical management of patients with a suspected norovirus infection.

Development of a geriatric resuscitation protocol, utilization compliance, and outcomes

Inconsistent application of trauma service resources and underevaluation of risk and resuscitation status in elderly trauma patients are problematic. We describe a geriatric protocol that includes initial lactate determination and trauma surgery admission. Protocol compliance rates were initial lactate determination, 67.9%; trauma service admission for overt or compensated (elevated lactate) shock, 73.6%; and trauma service consultation for nonshock patients, 67.8%. Implementation of this protocol resulted in a trend toward reduced mortality and reduced potentially preventable deaths.

Adverse outcomes associated with delayed intensive care consultation in medical and surgical inpatients

PURPOSE

The impact of delay in obtaining an intensive care unit (ICU) consult from inpatient wards is unclear. The goal of this study was to examine the effect of time to ICU consult from medical and surgical wards on mortality and length of stay (LOS).

MATERIALS AND METHODS

This was a retrospective study of 241 adult medical and surgical inpatients admitted at 2 tertiary care ICUs in Canada between 2007 and 2009. Neither institution has medical emergency teams (METs). Patient demographics, time when the patient would have fulfilled MET calling criteria (MET time), time of ICU consult, and ICU admission were analyzed. The main outcome variables were 30-day mortality and ICU LOS.

RESULTS

Multivariate analysis demonstrated an increase in mortality (odds ratio, 1.8; 95% confidence interval, 1.1-2.9; P = .01) with increased duration from MET time to ICU consult for medical patients. There was no effect of this period on ICU LOS in medical patients. In contrast, in surgical patients, the MET time to ICU consult duration was associated with an increased ICU LOS (coefficient, 2.1 for delay; 95% confidence interval, 0.26-3.8; P = .02) but had no effect on mortality.

CONCLUSIONS

Increased duration to ICU consult from MET time is associated with adverse outcomes. These adverse outcomes are different between medical and surgical patients.

Combined administration of anisodamine and neostigmine produces anti-shock effects: involvement of α7 nicotinic acetylcholine receptors

AIM

To evaluate the anti-effects of anisodamine and neostigmine in animal models of endotoxic and hemorrhagic shock.

METHODS

Kunming mice were injected with lipopolysaccharide (LPS 30 mg/kg, ip) to induce endotoxic shock. Anisodamine (12.5, 25, and 50 mg/kg, ip) and neostigmine (12.5, 25, and 50 μg/kg, ip) were administered immediately after LPS injection. Survival rate was monitored, and the serum levels of TNF-α and IL-1β were analyzed using ELISA assays. The effects of anisodamine and neostigmine were also examined in α7 nicotinic acetylcholine receptor (α7 nAChR) knockout mice with endotoxic shock and in Beagle dogs with hemorrhagic shock.

RESULTS

In mice with experimental endotoxemia, combined administration of anisodamine and neostigmine significantly increased the survival rate and decreased the serum levels of inflammatory cytokines, as compared to those produced by either drug alone. The anti-shock effect of combined anisodamine and neostigmine was abolished in α7 nAChR knockout mice. On the other hand, intravenous injection of the combined anisodamine and neostigmine, or the selective α7 nAChR agonist PNU282987 exerted similar anti-shock effects in dogs with hemorrhagic shock.

CONCLUSION

The results demonstrate that combined administration of anisodamine and neostigmine produces significant anti-shock effects, which involves activation of α7 nAChRs.

Infections caused by multidrug resistant organisms are not associated with overall, all-cause mortality in the surgical intensive care unit: the 20,000 foot view

BACKGROUND

Resistant pathogens are increasingly common in the ICU, with controversy regarding their relationship to outcomes. We hypothesized that an increasing number of infections with resistant pathogens in our surgical ICU would not be associated with increased overall mortality.

STUDY DESIGN

All ICU-acquired infections were prospectively identified between January 1, 2000 and December 31, 2009 in a single surgical ICU. Crude in-hospital, all-cause mortality data were obtained using a prospectively collected ICU database. Trends in rates were compared using linear regression.

RESULTS

A total of 799 resistant pathogens were identified (257 gram-positive, 542 gram-negative) from a total of 3,024 isolated pathogens associated with 2,439 ICU-acquired infections. The most frequently identified resistant gram-positive and -negative pathogens (defined as resistant to at least 1 major class of antimicrobials) were methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa, respectively. Pathogens were most commonly isolated from the lung, blood, and urine. The crude mortality rate declined steadily from 2000 to 2009 (9.4% to 5.4%; equation for trend y = -0.11x + 8.26). Linear regression analysis of quarterly rates revealed a significant divergence in trends between increasing total resistant infections (equation for trend y = 0.34x + 13.02) and percentage resistant infections (equation for trend y = 0.36x + 18.66) when compared with a decreasing mortality (p = 0.0003, p < 0.0001, respectively).

CONCLUSIONS

Despite a steady rise in the proportion of resistant bacterial infections in the ICU, crude mortality rates have decreased over time. The rates of resistant infections do not appear to be a significant factor in overall mortality in our surgical ICU patients.

Metformin-associated lactic acidosis following acute kidney injury. Efficacious treatment with continuous renal replacement therapy

INTRODUCTION

Metformin is a biguanide anti-hyperglycaemic drug. Metformin-associated lactic acidosis may sometimes be life-threatening. Continuous renal replacement therapy has been suggested as a method for resolving this extremely dangerous metabolic state. We describe the history of six patients admitted to the intensive care unit over a 28-month period in pre-shock conditions because of severe lactic acidosis, attributed to metformin-associated lactic acidosis, and successfully treated.

METHODS

We reviewed the charts of six patients admitted to our intensive care unit between January 2008 and May 2010. After initial assessment, all patients were treated with continuous renal replacement therapy. Admission serum lactate and creatinine levels, pH, need for ventilatory and cardiovascular support, as well as continuous renal replacement therapy details and length of stay were reviewed.

RESULTS

Admission pH levels of the six patients ranged between pH 6.63 and 7.0 and their serum lactate levels ranged between 12 and 27 mmol/l; the estimated creatinine clearance ranged between 6 and 24 ml min(-1)  1.73 m(-2) . All patients required vasoactive support and five required ventilatory support. Lactate levels decreased to near zero with continuous renal replacement therapy within 7-19 h in five of the patients whose intensive care unit length of stay ranged between 1 and 5 days. One patient's length of stay reached 11 days because of pneumonia, one died from multi-organ failure and another suffered permanent neurological damage following prolonged cardiopulmonary resuscitation before continuous renal replacement therapy was administered. All other patients recovered without sequellae.

CONCLUSIONS

Accurate recognition of metformin-associated lactic acidosis and prompt initiation of haemodialysis are paramount steps towards rapid recovery. Large series reports and controlled studies may better determine the optimal duration and best dialysis technique in these patients.

Review article: Part two: Goal-directed resuscitation--which goals? Perfusion targets

Haemodynamic targets, such as cardiac output, mean arterial blood pressure and central venous oxygen saturations, remain crude predictors of tissue perfusion and oxygen supply at a cellular level. Shocked patients may appear adequately resuscitated based on normalization of global vital signs, yet they are still experiencing occult hypoperfusion. If targeted resuscitation is employed, appropriate use of end-points is critical. In this review, we consider the value of directing resuscitation at the microcirculation or cellular level. Current technologies available include sublingual capnometry, video microscopy of the microcirculation and near-infrared spectroscopy providing a measure of tissue oxygenation, whereas base deficit and lactate potentially provide a surrogate measure of the adequacy of global perfusion. The methodology and evidence for these technologies guiding resuscitation are considered in this narrative review.

Blood lactate as a predictor for in-hospital mortality in patients admitted acutely to hospital: a systematic review

BACKGROUND

Using blood lactate monitoring for risk assessment in the critically ill patient remains controversial. Some of the discrepancy is due to uncertainty regarding the appropriate reference interval, and whether to perform a single lactate measurement as a screening method at admission to the hospital, or serial lactate measurements. Furthermore there is no consensus whether the sample should be drawn from arterial, peripheral venous, or capillary blood. The aim of this review was: 1) To examine whether blood lactate levels are predictive for in-hospital mortality in patients in the acute setting, i.e. patients assessed pre-hospitally, in the trauma centre, emergency department, or intensive care unit. 2) To examine the agreement between arterial, peripheral venous, and capillary blood lactate levels in patients in the acute setting.

METHODS

We performed a systematic search using PubMed, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and CINAHL up to April 2011. 66 articles were considered potentially relevant and evaluated in full text, of these ultimately 33 articles were selected.

RESULTS AND CONCLUSION

The literature reviewed supported blood lactate monitoring as being useful for risk assessment in patients admitted acutely to hospital, and especially the trend, achieved by serial lactate sampling, is valuable in predicting in-hospital mortality. All patients with a lactate at admission above 2.5 mM should be closely monitored for signs of deterioration, but patients with even lower lactate levels should be considered for serial lactate monitoring. The correlation between lactate levels in arterial and venous blood was found to be acceptable, and venous sampling should therefore be encouraged, as the risk and inconvenience for this procedure is minimal for the patient. The relevance of lactate guided therapy has to be supported by more studies.

[Measurement of lactic acid in multiple injury patients and its usefulness as a predictor of multiorgan failure and mortality]

INTRODUCTION

The use of lactic acid as marker of occult hyperfusion and its relationship with multiorgan failure (MOF) and/or mortality is a subject of debate.

MATERIAL AND METHOD

A prospective study was conducted on multiple injury patients over 16 years of age in critical care areas. The lactic acid was measured at the beginning and at 24 hours of the trauma and associating it with the patient morbidity and mortality.

RESULTS

A total of 342 patients, with a mean injury severity score of 24.1, were included. The patients who survived had an initial, and 24 hours after the trauma, lactic acid of 27.8 mg/dl and 17.9 mg/dl, respectively, (normal values less than 22 mg/dl), increasing to 36.5mg/dl and 40.2mg/dl, respectively, in those who died. There were no differences between the initial lactic acid in patients with and without MOF, being increased at 24 hours in those who had MOF (17.8 vs 26.7). The patients with a lactic acid that got worse or remained abnormal at 24 hours had a higher mortality than those in which it remained the same or improved (25% - 17.1% vs 6.3% - 0.8%), with the percentage of patients with MOF also increasing (40.6% - 32.8% vs 14.9% - 11.1%). In haemodynamically stable patients, there was also a higher mortality when the lactic acid got worse or remained abnormal in the first 24 hours (23.8% - 19.2% vs 8.8% - 0%), as well as a higher percentage of MOF (38.1% - 26.9% vs 10.9% - 7.6%).

CONCLUSIONS

The lactic acid results in the first 24 hours of the multiple injury patient are associated with mortality and MOF, even when the patient is haemodynamically stable.

Prevalence and significance of lactic acidosis in diabetic ketoacidosis

PURPOSE

The prevalence and clinical significance of lactic acidosis in diabetic ketoacidosis (DKA) are understudied. The objective of this study was to determine the prevalence of lactic acidosis in DKA and its association with intensive care unit (ICU) length of stay (LOS) and mortality.

METHODS

Retrospective, observational study of patients with DKA presenting to the emergency department of an urban tertiary care hospital between January 2004 and June 2008.

RESULTS

Sixty-eight patients with DKA who presented to the emergency department were included in the analysis. Of 68 patients, 46 (68%) had lactic acidosis (lactate, >2.5 mmol/L), and 27 (40%) of 68 had a high lactate (>4 mmol/L). The median lactate was 3.5 mmol/L (interquartile range, 3.32-4.12). There was no association between lactate and ICU LOS in a multivariable model controlling for Acute Physiology and Chronic Health Evaluation II, glucose, and creatinine. Lactate correlated negatively with blood pressure (r = -0.44; P < .001) and positively with glucose (r = 0.34; P = .004).

CONCLUSIONS

Lactic acidosis is more common in DKA than traditionally appreciated and is not associated with increased ICU LOS or mortality. The positive correlation of lactate with glucose raises the possibility that lactic acidosis in DKA may be due not only to hypoperfusion but also to altered glucose metabolism.

Lactate and acid base as a hemodynamic monitor and markers of cellular perfusion

BACKGROUND

: The intra- and postoperative monitoring of lactate and acid-base has been advocated in pediatric cardiac critical care as surrogate markers of cardiac output, oxygen delivery, and cellular perfusion. Many clinicians use lactate and base excess routinely as markers of tissue perfusion and to assess the effectiveness of their intervention. This review discusses the strengths and weaknesses of using these measurements in pediatric cardiac critical care.

METHODOLOGY

: A search of MEDLINE, EMBASE, PubMed, and the Cochrane Database was conducted to find controlled trials of lactate and base excess. Adult and pediatric data were considered. Guidelines published by the Society of Critical Care Medicine, the American Heart Association, the American Academy of Pediatrics, and the International Liaison Committee on Resuscitation were reviewed including further review of references cited.

RESULTS AND CONCLUSIONS

: Many factors other than tissue hypoxia may contribute to hyperlactemia in critical illness. Although the presence of hyperlactemia on admission appears to be associated with intensive care unit mortality and morbidity in some retrospective analyses, significant overlap between survivors and nonsurvivors means that nonsurvivors cannot be predicted from admission lactate measurement. Persistently elevated postoperative lactate is associated with increased morbidity and mortality in the pediatric cardiac population. To date there is no randomized control trial of goal-directed therapy in adult or pediatric cardiac care that includes normalization of lactate as a target. Overall equivalent time measurements of base excess, anion gap, and pH have a low predictive value for morbidity and mortality in children after cardiac surgery. Lactate is one of a cluster of markers of cellular perfusion and oxygen delivery. Alone, as a single measurement, it has minimal predictive value and is nondiscriminatory for survival.

Preoperative predictors of mortality in adult patients with perforation peritonitis

INTRODUCTION

There is paucity of data from India regarding the etiology, prognostic indicators, morbidity, and mortality patterns of perforation peritonitis. The objective of our study was to evaluate the predictors of mortality, preoperatively, for risk stratification of the patients and institution of an early goal-directed therapy.

MATERIALS AND METHODS

Eighty-four consecutive patients presenting with perforation peritonitis, in the age group of 14-70 years scheduled for emergency laparotomy were studied prospectively. The parameters studied were age and sex of the patients, associated co-morbidities, duration of symptoms, delay in initiating surgical intervention, and preoperative biochemical parameters such as hemoglobin, random blood sugar, blood urea, serum creatinine, pH, base excess, and serum lactate levels. In-hospital mortality was taken as the outcome.

RESULTS

We encountered a mortality of 17.8% in our study. Multiple linear (enter) regression identified the age, duration of symptoms, preoperative blood sugar levels, blood urea, serum creatinine levels, Mannheim Peritonitis Index, and the delay in instituting surgical intervention as independent predictors of mortality. Hyperlactatemia, acidosis and base excess were not found to be associated with mortality.

CONCLUSION

Routine biochemical investigations, delay in presentation, and surgical intervention are good predictors of mortality. Recognizing such patients early may help the anesthesiologists in risk stratification and in providing an early goal-directed therapy.

Femoral nailing during serum bicarbonate-defined hypo-perfusion predicts pulmonary organ dysfunction in multi-system trauma patients

OBJECTIVE

To assess the value of venous serum bicarbonate as an endpoint of resuscitation and guide to timing of femoral nailing in multi-system trauma patients.

DESIGN

Retrospective cohort study.

SETTING

Academic Level 1 Trauma Centre.

PATIENTS

Seventy-two consecutive adult multi-system trauma patients (Injury Severity Score≥15) with femoral shaft fracture (Orthopaedic Trauma Association Class 32-A to 32-C) treated with reamed medullary nail fixation.

INTERVENTION

Femoral nailing in the setting of hypo-perfusion defined by venous serum bicarbonate (SB). Threshold values of SB were determined first by correlating SB and simultaneously drawn arterial base deficit (BD). Then, corresponding values of SB to previously defined thresholds of hypo-perfusion based on BD were identified using regression analysis.

MAIN OUTCOME MEASUREMENT

Pulmonary organ dysfunction (POD) component of the Denver Multiple Organ Failure scoring system.

RESULTS

Simultaneous admission SB and BD values were correlated (r=-0.43, p=0.001). Adjusting for age, ISS and baseline POD, patients with SB<24.7 mequiv./L within 6 h of treatment had a 12-fold increase in POD (OR 12.2, 95% CI 1.5-98.6, p=0.019). This association was diminished, but still significant with hypo-perfusion present within 12 h prior to treatment (OR 5.6, 95% CI 1.0-29.1, p=0.042) and 24 h prior to treatment (OR 5.9, 95% CI 1.1-30.7, p=0.037).

CONCLUSIONS

Medullary fixation of femoral shaft fracture in the setting of serum bicarbonate-defined hypo-perfusion is associated with increased morbidity. Appropriate damage-control measures and aggressive resuscitation prior to definitive fracture care are advised and physiologic markers such as serum bicarbonate should guide clinical decision making rather than temporal distinctions.

Admission hyperlactatemia: causes, incidence, and impact on outcome of patients admitted in a general medical intensive care unit

PURPOSE

The aim of this study was to evaluate the causes, incidence, and impact on outcome of admission hyperlactatemia in patients admitted to a general medical intensive care unit (ICU).

METHODS

A retrospective cohort study was done in an 8-bed general ICU of tertiary care hospital over 15 months. Data regarding patient demographics, probable cause of hyperlactatemia, presence of shock, need for organ support, and ICU outcome were recorded. Patients were divided into 2 groups based on admission lactate levels as follows: high lactate (>2 mmol/L) and normal lactate (<2 mmol/L). Patients were compared in terms of need for organ support and ICU mortality.

RESULTS

Admission hyperlactatemia was present in 199 of 653 (30.47%) patients. Shock was the commonest cause, 53.3% patients, followed by respiratory and renal failure in 26 (13.1%) and 16 (8%) patients, respectively. Mean ± SD lactate levels in survivors and nonsurvivors were 1.64 ± 1.56 and 4.77 ± 4.72 mmol/L, respectively (P = .000). Receiver operating characteristic curve for lactate was 0.803 (95% confidence interval [CI], 0.753-0.853). Sensitivity and specificity of lactate (>2 mmol/L) to predict ICU mortality was 74.8% and 77.8%, respectively. Odds ratio for dying in patients with hyperlactatemia was 10.39 (95% CI, 6.378-16.925) with a relative risk of 1.538 (95% CI, 1.374-1.721). On subgroup analysis, in patients without hypotension too, ICU mortality was significantly increased in patients with hyperlactatemia (1.3% vs 6.45%, P = .009).

CONCLUSIONS

Admission hyperlactatemia is common in a general ICU and is associated with increased mortality, irrespective of presence of hypotension. Shock was the commonest cause for hyperlactatemia, followed by respiratory and renal failures.