Factors affecting outcome in the resuscitation of severely injured patients

Correlation between prehospital and in-hospital hypotension and outcomes after traumatic brain injury

BACKGROUND AND OBJECTIVE

Hypotension has a powerful effect on patient outcome after traumatic brain injury (TBI). The relative impact of hypotension occurring in the field versus during early hospital resuscitation is unknown. We evaluated the association between hypotension and mortality and non-mortality outcomes in four cohorts defined by where the hypotension occurred [neither prehospital nor hospital, prehospital only, hospital only, both prehospital and hospital].

METHODS

Subjects ≥10 years with major TBI were included. Standard statistics were used for unadjusted analyses. We used logistic regression, controlling for significant confounders, to determine the adjusted odds (aOR) for outcomes in each of the three cohorts.

RESULTS

Included were 12,582 subjects (69.8% male; median age 44 (IQR 26-61). Mortality by hypotension status: No hypotension: 9.2% (95%CI: 8.7-9.8%); EMS hypotension only: 27.8% (24.6-31.2%); hospital hypotension only: 45.6% (39.1-52.1%); combined EMS/hospital hypotension 57.6% (50.0-65.0%); (p < 0.0001). The aOR for death reflected the same progression: 1.0 (reference-no hypotension), 1.8 (1.39-2.33), 2.61 (1.73-3.94), and 4.36 (2.78-6.84), respectively. The proportion of subjects having hospital hypotension was 19.0% (16.5-21.7%) in those with EMS hypotension compared to 2.0% (1.8-2.3%) for those without (p < 0.0001). Additionally, the proportion of patients with TC hypotension was increased even with EMS "near hypotension" up to an SBP of 120 mmHg [(aOR 3.78 (2.97, 4.82)].

CONCLUSION

While patients with hypotension in the field or on arrival at the trauma center had markedly increased risk of death compared to those with no hypotension, those with prehospital hypotension that was not resolved before hospital arrival had, by far, the highest odds of death. Furthermore, TBI patients who had prehospital hypotension were five times more likely to arrive hypotensive at the trauma center than those who did not. Finally, even "near-hypotension" in the field was strongly and independently associated the risk of a hypotensive hospital arrival (<90 mmHg). These findings are supportive of the prehospital guidelines that recommend aggressive prevention and treatment of hypotension in major TBI.

Injuries associated with hypotension after trauma: Is it always haemorrhage?

Introduction

Restricted fluid replacement strategy is one part of damage control resuscitation for patients with trauma haemorrhage. However, not all patients presenting with physiological symptoms suggestive of haemorrhage are bleeding. This descriptive study aims to compare demographics and injuries in adult and older trauma patients presenting to the Emergency Department with hypotension versus normotension.

Methods

This was a retrospective, descriptive data analysis from a UK trauma registry. The records from one major trauma centre were analysed between 2014–2019, and every hypotensive (systolic blood pressure <90 mmHg) trauma patient investigated for injuries associated with hypotension. The hypotensive threshold for older patients was also adjusted to 110 mmHg for sub-cohort analysis.

Results

6245 trauma patients were included, of which 255 (4.1%) arrived hypotensive at the Emergency Department. Significant blood loss was identified in 32.2% of those cases. In 27.1%, multiple potential associations obscured the underlying mechanism for the hypotension but were more commonly associated with hypotension than with normotension. Over a third (37.5%) were ≥65 years old. Neurological injuries occurred more frequently in both older hypotensive groups than younger patients.

Conclusions

This study sought to compare injuries of adult and older trauma patients to aid trauma teams with decision making. In severely injured hypotensive patients, significant blood loss was the principal association with hypotension. However, several factors can mimic bleeding in the hypotensive trauma patient, which should be carefully considered. A prospective study is needed to clarify the characteristics and causes of bleeding mimics.

Optimal Out-of-Hospital Blood Pressure in Major Traumatic Brain Injury: A Challenge to the Current Understanding of Hypotension

STUDY OBJECTIVE

Little is known about the out-of-hospital blood pressure ranges associated with optimal outcomes in traumatic brain injuries (TBI). Our objective was to evaluate the associations between out-of-hospital systolic blood pressure (SBP) and multiple hospital outcomes without assuming any predefined thresholds for hypotension, normotension, or hypertension.

METHODS

This was a preplanned secondary analysis from the Excellence in Prehospital Injury Care (EPIC) TBI study. Among patients (age ≥10 years) with major TBIs (Barell Matrix type 1 and/or Abbreviated Injury Scale-head severity ≥3) and lowest out-of-hospital SBPs of 40 to 299 mmHg, we utilized generalized additive models to summarize the distributions of various outcomes as smoothed functions of SBP, adjusting for important and significant confounders. The subjects who were enrolled in the study phase after the out-of-hospital TBI guideline implementation were used to validate the models developed from the preimplementation cohort.

RESULTS

Among 12,169 included cases, the mortality model revealed 3 distinct ranges: (1) a monotonically decreasing relationship between SBP and the adjusted probability of death from 40 to 130 mmHg, (2) lowest adjusted mortality from 130 to 180 mmHg, and (3) rapidly increasing mortality above 180 mmHg. A subanalysis of the cohorts with isolated TBIs and multisystem injuries with TBIs revealed SBP mortality patterns that were similar to each other and to that of the main analysis. While the specific SBP ranges varied somewhat for the nonmortality outcomes (hospital length of stay, ICU length of stay, discharge to skilled nursing/inpatient rehabilitation, and hospital charges), the patterns were very similar to that of mortality. In each model, validation was confirmed utilizing the postimplementation cohort.

CONCLUSION

Optimal adjusted mortality was associated with a surprisingly high SBP range (130 to 180 mmHg). Below this level, there was no point or range of inflection that would indicate a physiologically meaningful threshold for defining hypotension. Nonmortality outcomes showed very similar patterns. These findings highlight how sensitive the injured brain is to compromised perfusion at SBP levels that, heretofore, have been considered adequate or even normal. While the study design does did not allow us to conclude that the currently recommended treatment threshold (<90 mmHg) should be increased, the findings imply that the definition of hypotension in the setting of TBI is too low. Randomized trials evaluating treatment levels significantly higher than 90 mmHg are needed.

Diffuse Axonal Injury: Clinical Prognostic Factors, Molecular Experimental Models and the Impact of the Trauma Related Oxidative Stress. An Extensive Review Concerning Milestones and Advances

Traumatic brain injury (TBI) is a condition burdened by an extremely high rate of morbidity and mortality and can result in an overall disability rate as high as 50% in affected individuals. Therefore, the importance of identifying clinical prognostic factors for diffuse axonal injury (DAI) in (TBI) is commonly recognized as critical. The aim of the present review paper is to evaluate the most recent contributions from the relevant literature in order to understand how each single prognostic factor determinates the severity of the clinical syndrome associated with DAI. The main clinical factors with an important impact on prognosis in case of DAI are glycemia, early GCS, the peripheral oxygen saturation, blood pressure, and time to recover consciousness. In addition, the severity of the lesion, classified on the ground of the cerebral anatomical structures involved after the trauma, has a strong correlation with survival after DAI. In conclusion, modern findings concerning the role of reactive oxygen species (ROS) and oxidative stress in DAI suggest that biomarkers such as GFAP, pNF-H, NF-L, microtubule associated protein tau, Aβ42, S-100β, NSE, AQP4, Drp-1, and NCX represent a possible critical target for future pharmaceutical treatments to prevent the damages caused by DAI.

Multiorgan Dysfunction After Severe Traumatic Brain Injury: Epidemiology, Mechanisms, and Clinical Management

Traumatic brain injury (TBI) is a major global health problem and a major contributor to morbidity and mortality following multisystem trauma. Extracranial organ dysfunction is common after severe TBI and significantly impacts clinical care and outcomes following injury. Despite this, extracranial organ dysfunction remains an understudied topic compared with organ dysfunction in other critical care paradigms. In this review, we will: 1) summarize the epidemiology of extracranial multiorgan dysfunction following severe TBI; 2) examine relevant mechanisms that may be involved in the development of multi-organ dysfunction following severe TBI; and 3) discuss clinical management strategies to care for these complex patients.

Multiple trauma management in mountain environments - a scoping review : Evidence based guidelines of the International Commission for Mountain Emergency Medicine (ICAR MedCom). Intended for physicians and other advanced life support personnel

Background

Multiple trauma in mountain environments may be associated with increased morbidity and mortality compared to urban environments.

Objective

To provide evidence based guidance to assist rescuers in multiple trauma management in mountain environments.

Eligibility criteria

All articles published on or before September 30th 2019, in all languages, were included. Articles were searched with predefined search terms.

Sources of evidence

PubMed, Cochrane Database of Systematic Reviews and hand searching of relevant studies from the reference list of included articles.

Charting methods

Evidence was searched according to clinically relevant topics and PICO questions.

Results

Two-hundred forty-seven articles met the inclusion criteria. Recommendations were developed and graded according to the evidence-grading system of the American College of Chest Physicians. The manuscript was initially written and discussed by the coauthors. Then it was presented to ICAR MedCom in draft and again in final form for discussion and internal peer review. Finally, in a face-to-face discussion within ICAR MedCom consensus was reached on October 11th 2019, at the ICAR fall meeting in Zakopane, Poland.

Conclusions

Multiple trauma management in mountain environments can be demanding. Safety of the rescuers and the victim has priority. A crABCDE approach, with haemorrhage control first, is central, followed by basic first aid, splinting, immobilisation, analgesia, and insulation. Time for on-site medical treatment must be balanced against the need for rapid transfer to a trauma centre and should be as short as possible. Reduced on-scene times may be achieved with helicopter rescue. Advanced diagnostics (e.g. ultrasound) may be used and treatment continued during transport.

Systolic Blood Pressure <110 mm Hg as a Threshold of Hypotension in Patients with Isolated Traumatic Brain Injuries

Hypotension is a known risk factor for poor neurologic outcomes after traumatic brain injury (TBI). Current guidelines suggest that higher systolic blood pressure (SBP) thresholds likely confer a mortality benefit. However, there is no consensus on the ideal perfusion pressure among different age groups (i.e., recommended SBP ≥100 mm Hg for patients age 50-69 years; ≥ 110 mm Hg for all other adults). We hypothesize that admission SBP ≥110 mm Hg will be associated with improved outcomes regardless of age group. A retrospective database review of the 2010-2016 Trauma Quality Improvement Program database was performed for adults (≥ 18 years) with isolated moderate-to-severe TBIs (head Abbreviated Injury Scale [AIS] ≥3; all other AIS <3). Sub-analyses were performed after dividing patients by SBP and age; comparison groups were matched with propensity score matching. Primary outcomes were early (6 h, 12 h, and 1 day) and overall in-hospital mortality. Overall, 154,725 patients met the inclusion criteria (mean age 62.8 ± 19.8 years, 89,431 [57.8%] males, Injury Severity Score13.9 ± 6.8). Multi-variate logistic regression showed that the risk of in-hospital mortality decreased with increasing SBP, plateauing at 110 mm Hg. Among patients of all ages, SBP ≥110 mm Hg was associated with improved mortality (SBP 110-129 vs. 90-109 mm Hg: 12 h 0.4% vs. 0.8%, p = 0.001; 1 day 0.8% vs. 1.4%, p = 0.004; overall 3.2% vs. 4.9%, p < 0.001). Among patients age 50-69 years, SBP ≥110 mm Hg was associated with improved mortality (SBP 110-119 vs. 100-109 mm Hg: 12 h 0.3% vs. 0.9%, p = 0.018; 1 day 0.5% vs. 1.5%, p = 0.007; overall 2.7% vs. 4.3%, p = 0.015). In conclusion, SBP ≥110 mm Hg is associated with lower in-hospital mortality in adult patients with isolated TBIs, including patients age 50-69 years. SBP <110 mm Hg should be used to define hypotension in adult patients of all ages.

Clinical Predictors of 3- and 6-Month Outcome for Mild Traumatic Brain Injury Patients with a Negative Head CT Scan in the Emergency Department: A TRACK-TBI Pilot Study

A considerable subset of mild traumatic brain injury (mTBI) patients fail to return to baseline functional status at or beyond 3 months postinjury. Identifying at-risk patients for poor outcome in the emergency department (ED) may improve surveillance strategies and referral to care. Subjects with mTBI (Glasgow Coma Scale 13–15) and negative ED initial head CT < 24 h of injury, completing 3- or 6-month functional outcome (Glasgow Outcome Scale-Extended; GOSE), were extracted from the prospective, multicenter Transforming Research and Clinical Knowledge in Traumatic Brain Injury (TRACK-TBI) Pilot study. Outcomes were dichotomized to full recovery (GOSE = 8) vs. functional deficits (GOSE < 8). Univariate predictors with p < 0.10 were considered for multivariable regression. Adjusted odds ratios (AOR) were reported for outcome predictors. Significance was assessed at p < 0.05. Subjects who completed GOSE at 3- and 6-month were 211 (GOSE < 8: 60%) and 185 (GOSE < 8: 65%). Risk factors for 6-month GOSE < 8 included less education (AOR = 0.85 per-year increase, 95% CI: (0.74–0.98)), prior psychiatric history (AOR = 3.75 (1.73–8.12)), Asian/minority race (American Indian/Alaskan/Hawaiian/Pacific Islander) (AOR = 23.99 (2.93–196.84)), and Hispanic ethnicity (AOR = 3.48 (1.29–9.37)). Risk factors for 3-month GOSE < 8 were similar with the addition of injury by assault predicting poorer outcome (AOR = 3.53 (1.17–10.63)). In mTBI patients seen in urban trauma center EDs with negative CT, education, injury by assault, Asian/minority race, and prior psychiatric history emerged as risk factors for prolonged disability.

Association of Out-of-Hospital Hypotension Depth and Duration With Traumatic Brain Injury Mortality

STUDY OBJECTIVE

Out-of-hospital hypotension has been associated with increased mortality in traumatic brain injury. The association of traumatic brain injury mortality with the depth or duration of out-of-hospital hypotension is unknown. We evaluated the relationship between the depth and duration of out-of-hospital hypotension and mortality in major traumatic brain injury.

METHODS

We evaluated adults and older children with moderate or severe traumatic brain injury in the preimplementation cohort of Arizona's statewide Excellence in Prehospital Injury Care study. We used logistic regression to determine the association between the depth-duration dose of hypotension (depth of systolic blood pressure <90 mm Hg integrated over duration [minutes] of hypotension) and odds of inhospital death, controlling for significant confounders.

RESULTS

There were 7,521 traumatic brain injury cases included (70.6% male patients; median age 40 years [interquartile range 24 to 58]). Mortality was 7.8% (95% confidence interval [CI] 7.2% to 8.5%) among the 6,982 patients without hypotension (systolic blood pressure ≥90 mm Hg) and 33.4% (95% CI 29.4% to 37.6%) among the 539 hypotensive patients (systolic blood pressure <90 mm Hg). Mortality was higher with increased hypotension dose: 0.01 to 14.99 mm Hg-minutes 16.3%; 15 to 49.99 mm Hg-minutes 28.1%; 50 to 141.99 mm Hg-minutes 38.8%; and greater than or equal to 142 mm Hg-minutes 50.4%. Log2 (the logarithm in base 2) of hypotension dose was associated with traumatic brain injury mortality (adjusted odds ratio 1.19 [95% CI 1.14 to 1.25] per 2-fold increase of dose).

CONCLUSION

In this study, the depth and duration of out-of-hospital hypotension were associated with increased traumatic brain injury mortality. Assessments linking out-of-hospital blood pressure with traumatic brain injury outcomes should consider both depth and duration of hypotension.

Mortality and Prehospital Blood Pressure in Patients With Major Traumatic Brain Injury: Implications for the Hypotension Threshold

IMPORTANCE

Current prehospital traumatic brain injury guidelines use a systolic blood pressure threshold of less than 90 mm Hg for treating hypotension for individuals 10 years and older based on studies showing higher mortality when blood pressure drops below this level. However, the guidelines also acknowledge the weakness of the supporting evidence.

OBJECTIVE

To evaluate whether any statistically supportable threshold between systolic pressure and mortality emerges from the data a priori, without assuming that a cut point exists.

DESIGN, SETTING, AND PARTICIPANTS

Observational evaluation of a large prehospital database established as a part of the Excellence in Prehospital Injury Care Traumatic Brain Injury Study. Patients from the preimplementation cohort (January 2007 to March 2014) 10 years and older with moderate or severe traumatic brain injury (Barell Matrix Type 1 classification, International Classification of Diseases, Ninth Revision head region severity score of 3 or greater, and/or Abbreviated Injury Scale head-region severity score of 3 or greater) and a prehospital systolic pressure between 40 and 119 mm Hg were included. The generalized additive model and logistic regression were used to determine the association between systolic pressure and probability of death, adjusting for significant/important confounders.

MAIN OUTCOMES AND MEASURES

The main outcome measure was in-hospital mortality.

RESULTS

Among the 3844 included patients, 2565 (66.7%) were male, and the median (range) age was 35 (10-99) years. The model revealed a monotonically decreasing association between systolic pressure and adjusted probability of death across the entire range (ie, from 40 to 119 mm Hg). Each 10-point increase of systolic pressure was associated with a decrease in the adjusted odds of death of 18.8% (adjusted odds ratio, 0.812; 95% CI, 0.748-0.883). Thus, the adjusted odds of mortality increased as much for a drop from 110 to 100 mm Hg as for a drop from 90 to 80 mm Hg, and so on throughout the range.

CONCLUSIONS AND RELEVANCE

We found a linear association between lowest prehospital systolic blood pressure and severity-adjusted probability of mortality across an exceptionally wide range. There is no identifiable threshold or inflection point between 40 and 119 mm Hg. Thus, in patients with traumatic brain injury, the concept that 90 mm Hg represents a unique or important physiological cut point may be wrong. Furthermore, clinically meaningful hypotension may not be as low as current guidelines suggest. Randomized trials evaluating treatment levels significantly above 90 mm Hg are needed.

Ankle Fractures and Modality of Hospital Transport at a Single Level 1 Trauma Center: Does Transport by Helicopter or Ground Ambulance Influence the Incidence of Complications?

In an era of concern over the rising cost of health care, cost-effectiveness of auxiliary services merits careful evaluation. We compared costs and benefits of Helicopter Emergency Medical Service (HEMS) with Ground Emergency Medical Service (GEMS) in patients with an isolated ankle fracture. A medical record review was conducted for patients with an isolated ankle fracture who had been transported to a level 1 trauma center by either HEMS or GEMS from January 1, 2000 to December 31, 2010. We abstracted demographic data, fracture grade, complications, and transportation mode. Transportation costs were obtained by examining medical center financial records. A total of 303 patients was included in the analysis. Of 87 (28.71%) HEMS patients, 53 (60.92%) had sustained closed injuries and 34 (39.08%) had open injuries. Of the 216 (71.29%) GEMS patients, 156 (72.22%) had closed injuries and 60 (27.78%) had open injuries. No significant difference was seen between the groups regarding the percentage of patients with open fractures or the grade of the open fracture (p = .07). No significant difference in the rate of complications was found between the 2 groups (p = 18). The mean baseline cost to transport a patient via HEMS was $10,220 + a $108/mile surcharge, whereas the mean transport cost using GEMS was $976 per patient + $16/mile. Because the HEMS mode of emergency transport did not significantly improve patient outcomes, health systems should reconsider the use of HEMS for patients with isolated ankle fractures.

Evaluation of the impact of implementing the emergency medical services traumatic brain injury guidelines in Arizona: the Excellence in Prehospital Injury Care (EPIC) study methodology

Traumatic brain injury (TBI) exacts a great toll on society. Fortunately, there is growing evidence that the management of TBI in the early minutes after injury may significantly reduce morbidity and mortality. In response, evidence-based prehospital and in-hospital TBI treatment guidelines have been established by authoritative bodies. However, no large studies have yet evaluated the effectiveness of implementing these guidelines in the prehospital setting. This article describes the background, design, implementation, emergency medical services (EMS) treatment protocols, and statistical analysis of a prospective, controlled (before/after), statewide study designed to evaluate the effect of implementing the EMS TBI guidelines-the Excellence in Prehospital Injury Care (EPIC) study (NIH/NINDS R01NS071049, "EPIC"; and 3R01NS071049-S1, "EPIC4Kids"). The specific aim of the study is to test the hypothesis that statewide implementation of the international adult and pediatric EMS TBI guidelines will significantly reduce mortality and improve nonmortality outcomes in patients with moderate or severe TBI. Furthermore, it will specifically evaluate the effect of guideline implementation on outcomes in the subgroup of patients who are intubated in the field. Over the course of the entire study (~9 years), it is estimated that approximately 25,000 patients will be enrolled.

Early predictors of mortality after spine trauma: a level 1 Australian trauma center study

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To identify early independent mortality predictors after spine trauma.

SUMMARY OF BACKGROUND DATA

Spine trauma consists of spinal cord and spine column injury. The ability to identify early (within 24 hours) risk factors predictive of mortality in spine trauma has the potential to reduce mortality and improve spine trauma management.

METHODS

Analysis was performed on 215 spine column and/or spinal cord injured patients from July 2008 to August 2011. Univariate and multivariate logistic regression models were applied to investigate the effects of the Injury Severity Score, age, mechanism of injury, blood glucose level, vital signs, brain trauma severity, morbidity before trauma, coagulation profile, neurological status, and spine injuries on the risk of in-hospital death.

RESULTS

Applying a multivariate logistic regression model, there were 7 independent early predictive factors for mortality after spine injury. They were (1) Injury Severity Score more than 15 (odds ratio [OR] = 3.67; P = 0.009), (2) abnormal coagulation profile (OR = 6; P < 0.0001), (3) patients 65 years or older (OR = 3.49; P = 0.007), (4) hypotension (OR = 2.9; P = 0.033), (5) tachycardia (OR = 4.04; P = 0.005), (6) hypoxia (OR = 2.9; P = 0.033), and (7) multiple comorbidities (OR = 3.49; P = 0.007). Severe traumatic brain injury was also associated with mortality but was excluded from multivariate analysis because there were no patients with this variable in the comparison group.

CONCLUSION

Mortality predictors for spine trauma patients are similar to those for general trauma patients. Spine injury variables were shown not to be independent predictors of spine trauma mortality.

Characteristics of hemodynamic disorders in patients with severe traumatic brain injury

Purpose. To define specific features of central hemodynamic parameter changes in patients with isolated severe traumatic brain injury (STBI) and in patients with clinically established brain death and to determine the required course of treatment for their correction. Data and Research Methods. A close study of central hemodynamic parameters was undertaken. The study involved 13 patients with isolated STBI (group STBI) and 15 patients with isolated STBI and clinically established brain death (group STBI-BD). The parameters of central hemodynamics were researched applying transpulmonary thermodilution. Results. In the present study, various types of hemodynamic reaction (normodynamic, hyperdynamic, and hypodynamic) were identified in patients with isolated STBI in an acute period of traumatic disease. Hyperdynamic type of blood circulation was not observed in patients with isolated STBI and clinically established brain death. Detected hemodynamic disorders led to the correction of the ongoing therapy under the control of central hemodynamic parameters. Conclusions. Monitoring of parameters of central hemodynamics allows to detect the cause of disorders, to timely carry out the required correction, and to coordinate infusion, inotropic, and vasopressor therapy.

Augmented central nitric oxide production inhibits vasopressin release during hemorrhage in acute alcohol-intoxicated rodents

Acute alcohol intoxication (AAI) attenuates the AVP response to hemorrhage, contributing to impaired hemodynamic counter-regulation. This can be restored by central cholinergic stimulation, implicating disrupted signaling regulating AVP release. AVP is released in response to hemorrhage and hyperosmolality. Studies have demonstrated nitric oxide (NO) to play an inhibitory role on AVP release. AAI has been shown to increase NO content in the paraventricular nucleus. We hypothesized that the attenuated AVP response to hemorrhage during AAI is the result of increased central NO inhibition. In addition, we predicted that the increased NO tone during AAI would impair the AVP response to hyperosmolality. Conscious male Sprague-Dawley rats (300-325 g) received a 15-h intragastric infusion of alcohol (2.5 g/kg + 300 mg·kg(-1)·h(-1)) or dextrose prior to a 60-min fixed-pressure hemorrhage (∼40 mmHg) or 5% hypertonic saline infusion (0.05 ml·kg(-1)·min(-1)). AAI attenuated the AVP response to hemorrhage, which was associated with increased paraventricular NO content. In contrast, AAI did not impair the AVP response to hyperosmolality. This was accompanied by decreased paraventricular NO content. To confirm the role of NO in the alcohol-induced inhibition of AVP release during hemorrhage, the nitric oxide synthase inhibitor, nitro-l-arginine methyl ester (l-NAME; 250 μg/5 μl), was administered centrally prior to hemorrhage. l-NAME did not further increase AVP levels during hemorrhage in dextrose-treated animals; however, it restored the AVP response during AAI. These results indicate that AAI impairs the AVP response to hemorrhage, while not affecting the response to hyperosmolality. Furthermore, these data demonstrate that the attenuated AVP response to hemorrhage is the result of augmented central NO inhibition.

Alcohol does not modulate the augmented acetylcholine-induced vasodilatory response in hemorrhaged rodents

Our previous studies have shown that acute alcohol intoxication (AAI) decreases blood pressure, exacerbates hypotension after hemorrhagic shock, impairs the pressor response to fluid resuscitation, and blunts neuroendocrine activation. We hypothesized that impaired hemodynamic compensation during and after hemorrhagic shock in the acute alcohol-intoxicated host is the result of blunted neuroendocrine activation or, alternatively, of an impaired vascular responsiveness to vasoactive agents. The aim of this study was to examine the effects of AAI, AAI and hemorrhagic shock, and AAI and hemorrhagic shock and resuscitation on reactivity of isolated blood vessel rings to phenylephrine and acetylcholine. Chronically instrumented, conscious male Sprague-Dawley rats (300-350 g) received a primed continuous 15-h intragastric alcohol infusion (2.5 g x kg(-1) + 300 mg x kg(-1) x h(-1)), and time-matched controls received an isocaloric-isovolumic dextrose infusion. At completion of infusions, animals were randomized to sham, 60-min fixed-pressure hemorrhage, or hemorrhagic shock followed by resuscitation with lactated Ringer's solution. At the completion of the experimental protocols, animals were killed, and thoracic aorta and mesenteric artery ring segments (1-2 mm) were prepared and studied in myograph baths. Acute alcohol intoxication did not produce significant alterations in either pressor or dilator responses in aortic or mesenteric rings. These findings suggest that impaired hemodynamic counterregulation during hemorrhagic shock in AAI is not due to decreased vasopressor responsiveness. However, our results suggest a role for accentuated vasodilatory responses that may be central in progression to decompensatory shock.

Transient central cholinergic activation enhances sympathetic nervous system activity but does not improve hemorrhage-induced hypotension in alcohol-intoxicated rodents

Morbidity and mortality after traumatic injury and hemorrhagic shock (HS) are exacerbated in the alcohol-intoxicated individual. The level of hypotension at the time of admittance into the emergency department is a critical indicator of outcome from injury. Previously, we have demonstrated that acute alcohol intoxication (AAI) decreases basal mean arterial blood pressure (MABP), exaggerates hypotension throughout HS, and attenuates the pressor response to fluid resuscitation in male rodents. This AAI-induced impaired hemodynamic counter-regulation to blood loss is associated with dampened neuroendocrine activation (i.e., epinephrine, norepinephrine, and arginine vasopressin [AVP] release). We hypothesize that the blunted neuroendocrine response is the principal mechanism involved in hemodynamic instability during and after HS in AAI. The present study investigates whether enhancing central cholinergic activity via intracerebroventricular (ICV) choline, a precursor of acetylcholine, would restore the neuroendocrine response and, as a result, improve hemodynamic compensation after HS. Chronically catheterized, conscious, male Sprague-Dawley rats (225-250 g) received a primed 15-h alcohol infusion (30% wt/vol; total approximately 8 g x kg(-1)) before ICV choline (150 microg) injection and were subsequently subjected to fixed-volume HS (50%) and fluid resuscitation with lactated Ringer's solution (2x volume removed). There were a total of eight experimental groups (n = 5-12 rats per group): alcohol-treated not hemorrhaged (alcohol/sham), dextrose-treated not hemorrhaged (dextrose/sham), alcohol-treated hemorrhaged (alcohol/hemorrhage), and dextrose-treated hemorrhaged (dextrose/hemorrhage), with ICV choline or water injection. Intracerebroventricular choline immediately increased basal MABP in both control (16%) and AAI animals (12%), but did not alter MABP after HS in either group. Intracerebroventricular choline increased basal plasma epinephrine (196%), norepinephrine (96%), and AVP (145%) and enhanced the HS-induced increase in epinephrine and AVP, without altering norepinephrine responses to HS, in control animals. Acute alcohol intoxication blunted choline-induced neuroendocrine activation and prevented the HS-induced increase in norepinephrine, without affecting post-HS epinephrine and AVP levels. Intracerebroventricular choline administration to AAI animals enhanced the HS-induced increase in epinephrine without affecting post-HS norepinephrine or AVP. These results indicate that ICV choline produced immediate neuroendocrine activation and elevation in MABP that was not sustained sufficiently to improve hemodynamic counter-regulation in alcohol-treated animals.

Central acetylcholinesterase inhibition improves hemodynamic counterregulation to severe blood loss in alcohol-intoxicated rats

Acute alcohol intoxication results in impaired hemodynamic counterregulation to blood loss and is associated with an attenuated hemorrhage-induced release of catecholamines and AVP. We speculated that restoration of the neuroendocrine response to hemorrhage would improve mean arterial blood pressure (MABP) recovery during acute alcohol intoxication. Previously, we demonstrated that intracerebroventricular (i.c.v.) choline, a precursor of acetylcholine, transiently increases sympathetic nervous system (SNS) outflow but is not capable of improving neuroendocrine and hemodynamic compensation to hemorrhage in alcohol-treated rats. We hypothesized that prolongation of the observed effect via i.c.v. neostigmine, an acetylcholinesterase inhibitor, would enhance SNS outflow, restore the neuroendocrine response, and in turn improve hemodynamic responses to hemorrhage during acute alcohol intoxication. I.c.v. neostigmine (1 microg) increased MABP, catecholamines, and AVP within 5 min and reversed hypotension due to 40% hemorrhage and intragastric alcohol (30% wt/vol, 2.5 g/kg) administration in chronically catheterized male Sprague-Dawley rats (225-250 g body wt). Acute alcohol intoxication before 50% hemorrhage decreased basal MABP, accentuated hypotension midhemorrhage, suppressed the hemorrhage-induced release of norepinephrine and AVP, and prevented restoration of MABP to basal levels after fluid resuscitation with lactated Ringer solution. I.c.v. neostigmine (0.5 microg) produced a sustained increase in MABP beginning at 30 min of hemorrhage that persisted throughout fluid resuscitation in control and alcohol-treated animals. I.c.v. neostigmine enhanced epinephrine responses and restored the hemorrhage-induced release of norepinephrine and AVP in alcohol-treated rats. These results demonstrate that inhibition of acetylcholinesterase in the central nervous system enhances SNS outflow, restores the neuroendocrine response to severe blood loss, and thereby improves hemodynamic counterregulation during acute alcohol intoxication. This study provides evidence for a central (and not peripheral) role of alcohol in impairing hemodynamic stability during hemorrhagic shock.

Measuring quality in trauma care

For use in quality measurement, a quality indicator (QI) must satisfy a number of criteria: there needs to be an established link with outcome; the indicator needs to measure what is considered current accepted practice; the targeted population requires precise definition; an appropriate risk adjustment strategy must be employed; the indicator should be feasible for collection; and, the measure must apply to a sufficient number of people so as to provide a measure of system-wide quality. This article discusses the use of QIs in the care of trauma patients. A series of QIs were originally promulgated by the American College of Surgeons Committee on Trauma (ACSCOT) and have been investigated for their utility in measuring quality in trauma systems by a number of US based studies. While some have advocated the implementation of several specific indicators, others have recommended discontinued use of a range of proposed QIs. This review highlights the difficulties of meeting these ideal indicator requirements in trauma care and proposes that the development of alternative indicators may provide more useful measures of quality care.

Influence of definition and location of hypotension on outcome following severe pediatric traumatic brain injury*

OBJECTIVE

To examine the influence of definition and location (field, emergency department, or pediatric intensive care unit) of hypotension on outcome following severe pediatric traumatic brain injury.

DESIGN

Retrospective cohort study.

SETTING

Harborview Medical Center (level I pediatric trauma center), Seattle, WA, over a 5-yr period between 1998 and 2003.

PATIENTS

Ninety-three children <14 yrs of age with traumatic brain injury following injury, head Abbreviated Injury Score > or = 3, and pediatric intensive care unit admission Glasgow Coma Scale score <9 formed the analytic sample. Data sources included the Harborview Trauma Registry and hospital records.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The relationship between hypotension and outcome was examined comparing two definitions of hypotension: a) systolic blood pressure <5th percentile for age; and b) systolic blood pressure <90 mm Hg. Hospital discharge Glasgow Outcome Score <4 or disposition of either death or discharge to a skilled nursing facility was considered a poor outcome. Pediatric intensive care unit and hospital length of stay were also examined. Systolic blood pressure <5th percentile for age was more highly associated with poor hospital discharge Glasgow Outcome Score (p = .001), poor disposition (p = .02), pediatric intensive care unit length of stay (rate ratio 9.5; 95% confidence interval 6.7-12.3), and hospital length of stay (rate ratio 18.8; 95% confidence interval 14.0-23.5) than systolic blood pressure <90 mm Hg. Hypotension occurring in either the field or emergency department, but not in the pediatric intensive care unit, was associated with poor Glasgow Outcome Score (p = .008), poor disposition (p = .03), and hospital length of stay (rate ratio 18.7; 95% confidence interval 13.1-24.2).

CONCLUSIONS

Early hypotension, defined as systolic blood pressure <5th percentile for age in the field and/or emergency department, was a better predictor of poor outcome than delayed hypotension or the use of systolic blood pressure <90 mm Hg.

Nontraumatic out-of-hospital hypotension predicts inhospital mortality

STUDY OBJECTIVE

Out-of-hospital hypotension may signify need for intensive resuscitation and rapid diagnosis on emergency department (ED) arrival. We hypothesized that nontraumatic out-of-hospital hypotension confers risk of inhospital mortality.

METHODS

This was a multicenter study of ambulance-transported, nontrauma, non-cardiopulmonary resuscitation patients conducted at 2 venues: (1) a cross-sectional risk assessment study of high-priority medical transports at a US metropolitan county; and (2) a Canadian prospective multicenter cohort study of patients with respiratory distress. Data at both venues were extracted from prospectively recorded, standardized run sheets by either a physician or a paramedic. Data extraction and analysis at each venue were conducted independently. Exposures to hypotension were defined as age older than 17 years old, systolic blood pressure less than 100 mm Hg during transport, and 1 or more of 10 predefined symptoms of circulatory insufficiency. Nonexposures to hypotension had the same definition as exposures, except the systolic blood pressure had to be more than 100 mm Hg during the entire out-of-hospital transport. The main outcome variable was inhospital mortality.

RESULTS

At venue 1, of 3,128 transports, 395 (13%) exposures and 395 nonexposures were identified. Inhospital mortality of exposures was 26% versus 8% for nonexposures (adjusted odds ratio [OR] 4.6; 95% confidence interval [CI] 2.0 to 5.9). At venue 2, of 7,679 transports, 532 exposures (7%) and 7,147 nonexposures were identified. Out-of-hospital exposure to hypotension conferred a mortality rate of 32% versus 11% for nonexposures (OR 3.0; 95% CI 2.4 to 3.7), representing a sensitivity of 18% and a specificity of 95%.

CONCLUSION

The inhospital mortality rate after out-of-hospital, nontraumatic hypotension is high and reproducible. Future research should focus on ED clinical protocols to ensure appropriate resuscitation and investigation of etiology of out-of-hospital hypotension.

IS THE REVISED TRAUMA SCORE STILL USEFUL?

The revised trauma score (RTS) has been embraced by the trauma community worldwide. Although originally developed as a triage tool, the use of the RTS has since been expanded to include the prediction of outcome following traumatic injury. Through a critical review of the literature, evidence for use of the RTS is discussed along with the limitations of this commonly used tool. In summary, the RTS is a well-established predictor of mortality in trauma populations, but there is a lack of definitive evidence supporting its use as a primary triage tool and as a predictor of outcomes other than mortality. Difficulty in collecting the components of the RTS creates issues for data validity and the use of the RTS as a research tool. Although the weighted RTS has been developed to improve the prediction capacity of the RTS, studies reporting its use are few and there is debate regarding the applicability of the published coefficients for broad use. Overall, further studies are warranted to clearly establish the usefulness of the RTS as a triage tool in the field, to further evaluate the weighted version of the RTS, and to determine the ability of the RTS to predict functional outcome and quality of life. In particular, future research is needed to address these issues in Australian trauma populations.

A brief episode of hypotension increases mortality in critically ill trauma patients

OBJECTIVE

Hypotension is associated with increased mortality, however previous studies have failed to account for the depth and duration of hypotension. We evaluated the effect of the duration of hypotension on outcome in injured patients.

METHODS

Trauma patients admitted to the intensive care unit (ICU) from 1999 to 2000 were prospectively evaluated. Patients transferred to a ward </= 48 hours after admission were excluded. The lowest systolic blood pressure and duration of all episodes of systolic blood pressure below 90 mm Hg were recorded along with the total ICU length of stay and discharge status. The Kruskal-Wallis test, Pearson chi2, and test for trend were used for analysis.

RESULTS

Patients with hypotension during the first 24 hours of ICU care had an increased mortality rate. A brief (</= 10 minutes) episode of hypotension was associated with increased mortality that increased with duration of hypotension (p = 0.0001). ICU length of stay also increased with duration of hypotension (p = 0.0001).

CONCLUSION

Brief episodes of hypotension are associated with an increased risk of death in patients requiring admission to the ICU after injury and a longer ICU recovery for those who survive.

The Brain Trauma Foundation. The American Association of Neurological Surgeons. The Joint Section on Neurotrauma and Critical Care. Resuscitation of blood pressure and oxygenation

Early postinjury episodes of hypotension or hypoxia greatly increase morbidity and mortality from severe head injury. At present, defining level of hypotension and hypoxia is unclear in these patients. However, ample class II evidence exists regarding hypotension, defined as a single observation of a systolic blood pressure of <90/mm Hg, or hypoxia, defined as apnea/cyanosis in the field or a PaO2 < 60 mm Hg by arterial blood gas analysis, to warrant the formation of guidelines stating that these values must be avoided, if possible, or rapidly corrected in severe head injury patients. A significant proportion of adult and pediatric TBI patients are discovered to be hypoxemic or hypotensive in the prehospital setting. Patients with severe head injury that are intubated in the prehospital setting appear to have better outcomes. Strong class II evidence suggests that raising the blood pressure in hypotensive, severe head injury patients improves outcome in proportion to the efficacy of the resuscitation.

The effect of polytrauma in persons with traumatic spine injury. A prospective database of spine fractures

STUDY DESIGN

A mixed cross-sectional survey and cohort study using a prospectively gathered database of persons with traumatic spine injury.

OBJECTIVES

To identify demographic and injury mechanism factors that predict greater injury severity, and to determine the effect of injury severity on outcomes in traumatic spine fracture.

SUMMARY OF BACKGROUND DATA

Traumatic spine fracture outcome studies have focused on defining type and level of vertebral fracture without considering the severity of associated injuries. In the trauma population, greater injury severity has been shown to be related to worse outcome. No studies have been reported on the effect of injury severity on outcome in the traumatic spine fracture population.

METHODS

Prospectively collected data on 830 persons with traumatic spine injury who were admitted to a trauma hospital were reviewed. Patient demographics; injury mechanism; hospital events; and disability, employment, and pain status at discharge, 1 year, and 2 years after injury were recorded. Associations between these factors and trauma severity (Injury Severity Score) were explored using Pearson's correlation and analysis of variance.

RESULTS

Trauma was more severe in patients who had been married previously, who were involved in a motor vehicle accident, were ejected from the vehicle, had loss of consciousness, had higher-level and multiple complicated vertebral fractures, or had neurologic deficit. Those more severely injured had longer lengths of stay, more surgery, more complications, higher mortality, more disability, and less return to work.

CONCLUSIONS

Persons with traumatic spine injury and polytrauma have poorer short- and long-term outcomes. This high-risk group may require aggressive interventions, more hospital resources, and close follow-up observation after discharge from hospital to optimize outcome.

Neurotrauma care in the new millennium

The next millennium will see an explosion of neuromonitoring technology that will provide a more detailed understanding of brain-injured patients. This understanding will allow an individualized and intelligent application of the wide range of therapies that will become available. The measure of success for all of these endeavors will be individual patients and physicians' ability to return them to their normal lives.

Outcome after hemorrhagic shock in trauma patients

BACKGROUND

It is essential to identify patients at high risk of death and complications for future studies of interventions to decrease reperfusion injury.

METHODS

We conducted an inception cohort study at a Level I trauma center to determine the rates and predictors of death, organ failure, and infection in trauma patients with systolic blood pressure < or = 90 mm Hg in the field or in the emergency department.

RESULTS

Among the 208 patients with hemorrhagic shock (blood pressure < or = 90 mm Hg), 31% died within 2 hours of emergency department arrival, 12% died between 2 and 24 hours, 11% died after 24 hours, and 46% survived. Among those who survived > or = 24 hours, 39% developed infection and 24% developed organ failure. Increasing volume of crystalloid in the first 24 hours was strongly associated with increased mortality (p = 0.00001).

CONCLUSION

Hemorrhage-induced hypotension in trauma patients is predictive of high mortality (54%) and morbidity. The requirement for large volumes of crystalloid was associated with increased mortality.

Methods and results of the treatment of peacetime and wartime multiple injuries--a comparative study

Seventy-one patients suffering from multiple injuries were divided into two groups, according to the manner in which the injuries were inflicted. Forty-one were injured in 'peacetime' circumstances (road traffic accidents, 85.4 per cent), and 30 patients were injured during 'military' shelling or in combat. Since there is no generally accepted severity scoring of wartime multiple injuries, this paper has offered one. A 'peacetime' scoring system was used to compare the hospital mortality in the two groups. The severity of injuries in both groups was estimated by using the Injury Severity Score. There was no statistically significant difference between the two groups with regard to injury severity, age, hospital mortality rate, received infusion, or the number of specialists involved in treatment. The differences between the two groups were significant in the application of transfusion and antibiotics, number of operations performed, and the time span between injury and operation.

Value of the prospective 'before and after' study as a methodology to evaluate outcome in a trauma centre

A series of interventions (administrative, clinical and educational) was introduced to improve the quality of trauma care at Royal Prince Alfred Hospital, the designated trauma centre for the Central Sydney Area Health Service (CSAHS). A prospective, 'before and after' study was conducted to assess changes in outcome following the introduction of these measures. The trauma centre survival rate for patients admitted with serious injury (Injury Severity Scores > 15) increased significantly, from 72% in the nine months before trauma centre designation to 89% in the nine months after (P = 0.005). The peer review designated, potentially avoidable death rate did not change significantly over the two study periods, remaining in the 20-30% range. Similarly the unexpected death rate (TRISS) did not change significantly, remaining in the 20-45% range. A trend to a lower trauma centre mortality in those arriving with a systolic blood pressure < or = 90 mmHg was noted. Seven out of 14 patients 'at risk' from exsanguination died in the first 9 months compared with one out of seven in the second 9 months (P = 0.17). An unexpected finding was a change in the degree of injury severity and physiological status in patients arriving at the trauma centre. The Injury Severity Scores were significantly lower (P = 0.008) and the Revised Trauma Scores significantly higher (P = 0.0006) in the latter 9 months of the study. It was concluded that the improved trauma centre survival rate was a reflection of a reduced hospital mortality from haemorrhagic shock in conjunction with a lesser degree of injury severity in patients admitted from the CSAHS.