Effect of ethanol on lactic acidosis in experimental hemorrhagic shock

Symptom-level modelling unravels the shared genetic architecture of anxiety and depression

Depression and anxiety are highly prevalent and comorbid psychiatric traits that cause considerable burden worldwide. Here we use factor analysis and genomic structural equation modelling to investigate the genetic factor structure underlying 28 items assessing depression, anxiety and neuroticism, a closely related personality trait. Symptoms of depression and anxiety loaded on two distinct, although highly genetically correlated factors, and neuroticism items were partitioned between them. We used this factor structure to conduct genome-wide association analyses on latent factors of depressive symptoms (89 independent variants, 61 genomic loci) and anxiety symptoms (102 variants, 73 loci) in the UK Biobank. Of these associated variants, 72% and 78%, respectively, replicated in an independent cohort of approximately 1.9 million individuals with self-reported diagnosis of depression and anxiety. We use these results to characterize shared and trait-specific genetic associations. Our findings provide insight into the genetic architecture of depression and anxiety and comorbidity between them.

Is blood alcohol level a good predictor for injury severity outcomes in motor vehicle crash victims?

Experimental studies in animals suggest that alcohol may influence pathophysiologic response to injury mechanisms. However, biological evidence for the alcohol-injury severity relationship provides conflicting results. The purpose of our retrospective cross-sectional study in 2,323 people was to assess whether blood alcohol level (BAC) adversely influences injury severity in victims of motor vehicle collisions (MVCs). We found no difference in mortality OR 1.09 (0.73–1.62), or length of hospital stay, and a trend for lower ISS score was found in the high-alcohol group (P = 0.052). Furthermore, the high-alcohol group demonstrated a lower adjusted rate of severe head injury OR 0.65 (0.48–0.87), chest injury OR 0.58 (0.42–0.80), and serious extremity injury OR 0.10 (0.01–0.76). The findings of our study do not demonstrate a dose-response relationship between alcohol consumption and injury severity in MVCs. This study implies that higher BAC may lead to less severe injuries, without impacting mortality or length of hospital stay, however, further research is required to elucidate the nature of this relationship.

Consequences of alcohol-induced early dysregulation of responses to trauma/hemorrhage

Acute alcohol intoxication is a frequent underlying condition associated with traumatic injury. Studies from our laboratory have been designed to examine the early hemodynamic, proinflammatory, and neuroendocrine alterations in responses to hemorrhagic shock in surgically catheterized, conscious, unrestrained, male Sprague-Dawley rats during acute alcohol intoxication (1.75-g/kg bolus, followed by a constant 15-h infusion at a rate of 250-300 mg/kg/h). With both fixed-pressure (40 mm Hg) and fixed-volume (50%) hemorrhagic shock, followed by fluid resuscitation with Ringer's lactate, acute (15 h) alcohol intoxication has been shown to impair significantly the immediate hemodynamic, metabolic, and inflammatory counterregulatory responses to hemorrhagic shock. Alcohol intoxication enhanced hemodynamic instability during blood loss and impaired the recovery of mean arterial blood pressure during fluid resuscitation. Activation of neuroendocrine pathways involved in restoring hemodynamic stability was significantly attenuated in alcohol-intoxicated hemorrhaged animals. The hemodynamic and neuroendocrine impairment is associated with enhanced expression of lung and spleen tumor necrosis factor, and it suppressed circulating neutrophil function. In addition, neuroimmune regulation of cytokine production by spleen-derived macrophages obtained from alcohol-intoxicated hemorrhaged animals was impaired when examined in vitro. We hypothesize that impaired neuroendocrine activation contributes to hemodynamic instability, which, in turn, prolongs tissue hypoperfusion and enhances risk for tissue injury. Specifically, the early dysregulation in counterregulatory responses is hypothesized to affect host defense mechanisms during the recovery period. We examined host response to systemic (cecal ligation and puncture) and localized (pneumonia) infectious challenge in animals recovering from hemorrhage during acute alcohol intoxication. Increased morbidity and mortality from infection were observed in alcohol-intoxicated hemorrhaged animals. Our results indicate that alcohol-induced alterations in early hemodynamic and neuroimmune responses to shock have an impact on susceptibility to an infectious challenge during the early recovery period.

Acute Alcohol Intoxication During Hemorrhagic Shock: Impact on Host Defense From Infection

BACKGROUND

Acute alcohol intoxication is a frequent underlying condition associated with traumatic injury. Our studies have demonstrated that acute alcohol intoxication significantly impairs the immediate hemodynamic, metabolic, and inflammatory responses to hemorrhagic shock. This study investigated whether acute alcohol intoxication during hemorrhagic shock would alter the outcome from an infectious challenge during the initial 24 hr recovery period.

METHODS

Chronically catheterized male Sprague Dawley rats were randomized to acute alcohol intoxication (EtOH; 1.75 g/kg bolus followed by a constant 15 hr infusion at 250-300 mg/kg/hr) or isocaloric isovolemic dextrose infusion (dex; 3 ml + 0.375 ml/hr). EtOH and dex were assigned to either fixed-volume (50%) hemorrhagic shock followed by fluid resuscitation with Ringer's lactate (EtOH/hem, dex/hem) or sham hemorrhagic shock (EtOH/sham, dex/sham). Indexes of circulating neutrophil function (apoptosis, phagocytosis, oxidative burst) were obtained at baseline, at completion of hemorrhagic shock, and at the end of fluid resuscitation. Bacterial clearance, lung cytokine expression, and myeloperoxidase activity were determined at 6 and 18 hr after an intratracheal challenge with Klebsiella pneumoniae (10 colony-forming units).

RESULTS

Mean arterial blood pressure was significantly lower in acute alcohol intoxication-hemorrhagic shock animals throughout the hemorrhagic shock. In sham animals, acute alcohol intoxication alone did not produce significant changes in neutrophil apoptosis or phagocytic activity but significantly suppressed phorbol myristic acid (PMA)-stimulated oxidative burst. Hemorrhagic shock produced a modest increase in neutrophil apoptosis and suppression of neutrophil phagocytic capacity but significantly suppressed PMA-stimulated oxidative burst. Acute alcohol intoxication exacerbated the hemorrhagic shock-induced neutrophil apoptosis and the hemorrhagic shock-induced suppression of phagocytosis without further affecting PMA-stimulated oxidative burst. Fluid resuscitation did not restore neutrophil phagocytosis or oxidative burst. Acute alcohol intoxication decreased (-40%) 3-day survival from K. pneumoniae in hemorrhagic shock animals, impaired bacterial clearance during the first 18 hr postinfection, and prolonged lung proinflammatory cytokine expression.

CONCLUSIONS

These results demonstrate that the early alterations in metabolic and inflammatory responses to hemorrhagic shock produced by acute alcohol intoxication are associated with neutrophil dysfunction and impaired host response to a secondary infectious challenge leading to increased morbidity and mortality.

Ethanol intoxication and lactated Ringer's resuscitation prolong hemorrhage-induced lactic acidosis

Ethanol (EtOH) blunts the respiratory and metabolic compensation during hemorrhage, resulting in a more severe lactic acidemia. We hypothesized that lactated Ringer's (LR) resuscitation may exacerbate this lactic acidemia. Male guinea pigs were implanted with arterial and venous catheters. Two days after catheter placement, conscious animals were injected intraperitoneally with 1 g/kg EtOH, 0.3 g/kg EtOH, or an equal volume of water 30 min before hemorrhage (60% of estimated blood volume). After 30 min of hemorrhagic shock, animals were resuscitated with isotonic saline (S) or LR at 1 mL/min (three times shed blood volume). Mean arterial blood pressure (MABP) was not affected by pretreatment with either dose of EtOH, but was significantly decreased by hemorrhage in all groups. Both S and LR resuscitation slightly increased MABP, but neither restored it to prehemorrhage values. Blood lactate levels increased in all groups during hemorrhage and remained elevated for 3 h in animals pretreated with 1 g/kg EtOH. In the group pretreated with 0.3 g/kg EtOH, pH decreased during shock but returned to prehemorrhage levels during the resuscitation period. Resuscitation with S returned pH to prehemorrhage values in animals pretreated with 1.0 g/kg EtOH. Resuscitation with LR did not exacerbate, but did prolong, the lactic acidemia after shock in animals pretreated with 1.0 g/kg EtOH. Administration of additional lactate during intoxication and hypovolemia for hemodynamic stabilization before blood transfusion may exacerbate a metabolic stress.

Alcohol intoxication increases morbidity in drivers involved in motor vehicle accidents

We prospectively examined the correlation of alcohol intoxication with injury severity, morbidity, and mortality in drivers involved in motor vehicle accidents in a prospective cohort study. The study enrolled 923 injured patients, of whom 421 were legally intoxicated (blood alcohol concentration [BAC] > or = 50 mg/dL) and 502 were not intoxicated (BAC < 50 mg/dL). The intoxicated drivers had a significantly higher injury severity score (ISS), lower Glasgow Coma Score, lower systolic blood pressure; higher rate in old age, male sex, greater rate of habitual drinking, greater lack of use of safety gear, and greater accident-related morbidity. After logistic regression analysis, alcohol intoxication was not associated with severe injury (ISS > or = 9); however, alcohol intoxication analyzed either as a preinjury or postinjury risk factor, was one of the predictors for morbidity. Severe head injury was the only predictor of mortality. In conclusion, although alcohol intoxication is not associated with an increased incidence of severe injury or mortality in drivers involved in motor vehicle crashes, it is one of the significant predictors for morbidity after injury.

Acute ethanol binge followed by withdrawal regulates production of reactive oxygen species and cytokine-induced neutrophil chemoattractant and liver injury during reperfusion after hepatic ischemia

This work tests the hypothesis that withdrawal from an acute ethanol binge regulates the production of reactive oxygen species (ROS) and chemokines by Kupffer cells, and as a result compromises or protects the liver from injury. Male Sprague-Dawley rats received an intravenous ethanol bolus (1.75 g/kg), followed by an intravenous infusion of 200-300 mg/kg/h for 12 h. At 12 h, ethanol infusion was stopped and replaced by saline. At 18 h, rats were subjected to 45 min of partial hepatic ischemia, followed by 0-24 h of reperfusion (I/R). At specific time points, Kupffer cells were isolated for superoxide anion assay and CINC (cytokine-induced neutrophil chemoattractant) and MIP-2 (macrophage inflammatory protein-2) production in vitro. Alanine transferase (ALT) activity, endotoxin, CINC, and MIP-2 were measured in serum samples taken at appropriate intervals. Results show that at 3 h post reperfusion, serum ALT was significantly elevated in the ethanol-treated group + I/R, compared with the saline + I/R group. ROS production by Kupffer cells at this time was also significantly increased compared with the saline + I/R group. However, ethanol withdrawal + I/R did not significantly alter CINC and MIP-2 production at 3 h of reperfusion. After 24 h, serum ALT was lower in the ethanol + I/R group than in the saline + I/R group. Superoxide anion and MIP-2 releases by Kupffer cells were not statistically significantly different between these two groups at this time. CINC production by Kupffer cells from the ethanol-treated + I/R group was significantly lower than in the saline + I/R group. Concomitantly, CINC and nuclear factor-kappaB (NF-kappaB) mRNAs and NF-kappaB translocation and binding in Kupffer cells in this treatment group were down-regulated. Moreover, the number of polymorphonuclear neutrophils (PMNs) sequestered in the liver was significantly lower in the ethanol + I/R group than in the saline-treated group. ROS and chemokine productions in sham animals with or without ethanol were lower than in the I/R group. These data suggest that acute ethanol binge followed by withdrawal may compromise the liver to injury during the early phase, whereas in the later phase it may be protective. Furthermore, these results support the notion that Kupffer cells are involved in hepatic injury in the early phase, whereas PMNs participate more actively during the later phase of reperfusion.

Women, alcohol, and driving

Alcohol-related crashes and fatalities have shown a dramatic decrease over the last decade. While males continue to account for most alcohol-related crashes, females are an increasing proportion of alcohol-involved drivers in both fatal and nonfatal crashes. Although most research has not addressed the possibility of gender differences in the effects of alcohol on driving performance, available evidence suggests that such differences may exist. Alcohol appears to have greater effects on females in terms of biomedical damage and impaired performance, although these effects have not been systematically investigated in relation to driving. Effective prevention programs for women require more focused research to understand gender-related factors in the effects of alcohol on driving.

Base deficit level indicating major injury is increased with ethanol

Analyses were performed to determine whether ethanol increases base deficit, independent of major injury, in blunt trauma patients from two Level I trauma centers. In 2140 Baltimore patients, base deficit was significantly higher in ethanol-positive patients (blood level > or =0.01%), independent of blood pressure (BP), Injury Severity Score (ISS), and blood loss. In 139 Youngstown, Ohio, patients, base deficit was significantly higher in ethanol-positive patients, independent of ISS and RBC units given. In 1796 awake Baltimore patients, major injury was defined as an ISS >10, presence of blood loss, or need for RBC transfusion. A base deficit < or =-4.1 for ethanol-positive and < or =-1.1 for ethanol-negative patients had higher rates of major injury (odds ratio 3.2 and 2.1, respectively) and abdominal trauma (odds ratio 3.6 and 3.2, respectively). In blunt trauma patients, base deficit is increased with ethanol, independent of major injury. A base deficit of < or =-4.1 for ethanol-positive and < or =-1.1 for ethanol-negative awake patients may be an early warning for occult injury and suggest the need for an abdominal computed tomography (CT) scan or ultrasound.

Effects of alcohol on the geographic variation of driver fatalities in motor vehicle crashes

OBJECTIVE

To determine whether the increased risk of dying in a rural vs nonrural motor vehicle crash (MVC) can be attributed to driver demographics, crash characteristics, or police-reported alcohol use.

METHODS

A retrospective cohort study was conducted, comparing all rural (116,242) and a 20% random sample of nonrural (104,197) Michigan drivers involved in an MVC during 1994-1996. Data consisted of all police-reported traffic crashes on public roadways. A logistic regression model was created, using survival as the dependent variable and gender, age, crash characteristics, and rural or nonrural county as independent variables. Driver alcohol use, as reported by the investigating officer, was introduced into the model, and the effect was analyzed.

RESULTS

Nonsurvivors represented 0.2% of the total; 99.8% were survivors. Police-reported alcohol use was reported for 3.9% of drivers. Drivers in rural MVCs were more likely to be male, to be more than 50 years of age, to have been drinking alcohol, and to have more severe vehicle deformation as a result of the MVC. The relative risk (RR) for MVC nonsurvivors was 1.69 [95% confidence interval (CI) = 1.3 to 2.1] times higher for drivers in rural than nonrural counties. After adjusting for demographic and crash characteristics, the RR was 1.56 (95% CI = 1.2 to 1.9). Controlling for alcohol and its interactions decreased the RR to 1.26 (95% CI = 0.6 to 2.4), a nonsignificant difference between rural and nonrural MVC mortalities.

CONCLUSIONS

Alcohol use by drivers in Michigan was a significant contributor for nonsurvivors of rural crashes. Efforts to decrease rural MVC mortality must address alcohol use.

Effects of ethanol on brain lactate in experimental traumatic brain injury with hemorrhagic shock

OBJECTIVE

Previous studies of traumatic brain injury (TBI) and hemorrhagic shock (HS) models, have shown cardiorespiratory depression in ethanol-treated animals. This study investigated the effects of ethanol (ET) on brain lactate concentrations and acidosis in a TBI/HS model.

METHODS

Anesthetized swine were instrumented and subjected to injury (INJ) consisting of fluid percussion TBI of 3 atm with concurrent 30 ml/kg graded hemorrhage over 30 min. Three groups were studied: Sham, INJ and INJ/ET. ET was given preinjury as a 2-g/kg i.v. bolus over 30 min, and an infusion of 0.4 g kg(-1) h(-1). Cardiorespiratory and cerebral physiologic data were monitored continuously for 150 min postinjury. Cerebral and renal blood flow was measured with colored microspheres. Brains were frozen in situ with liquid nitrogen. Lactate was measured with an enzymatic method.

RESULTS

ET levels at injury were 219+/-24 mg/dl. The INJ/ET group had increased mortality, impaired ventilation, and reduced renal blood flow. Brain (cortical) lactate levels were significantly higher and cerebral venous lactate concentrations were increased in the INJ/ET group during the postinjury period. Cerebral venous glucose was significantly higher in the INJ/ET group, and cerebral venous pH was significantly lower.

CONCLUSION

In this TBI/HS model, ethanol-induced increases in lactate concentrations in brain tissue and cerebral venous blood are associated with respiratory depression and reduced organ blood flow.

Alcohol and injury severity: reappraisal of the continuing controversy

It is well recognized that alcohol increases the risk of injury. It is controversial, however, whether alcohol also has an effect on the degree and outcome of injury after controlling for the severity of impact. This review examines the evidence from experimental studies in animals regarding the potentiating effects of alcohol on trauma, and the methodologic issues that may have contributed to the contradictory findings of clinical and epidemiologic studies. Most experimental studies indicate that alcohol can adversely affect the degree and outcome of injury. In controlled laboratory conditions, alcohol is found to reduce cardiac output, to increase the susceptibility to hemorrhagic shock, and to increase the pulmonary vascular resistance after standardized experimental injuries. However, it is difficult to extrapolate these findings to humans, partly because the interactive effects of chronic and acute alcohol use on trauma are rarely considered in experimental studies. The conflicting results in studies involving trauma patients are due in part to the differences in study design, particularly selection of study populations, and in measuring and controlling for kinetic forces on the body. Studies indicating that alcohol is associated with an increased risk of serious or fatal injury are usually based on data from emergency departments or police departments. The alcohol-injury severity relationship reported in these studies is attributable to a great extent to the effects of correlates of alcohol, such as speeding and not wearing seat belts, rather than the biological effects of alcohol. Studies indicating that alcohol is not associated with the degree and outcomes of injury are mostly those involving patients who were admitted to hospitals or trauma centers. Methodologic issues concerning the alcohol-injury severity controversy, including conceptual models and future research needs, are discussed.

Effects of ethanol in traumatic brain injury

The effects of ethanol intoxication on brain injury and cerebral blood flow (CBF) were investigated in a porcine fluid-percussion model of traumatic brain injury (TBI). Immature swine, under halothane anesthesia (1%), had a TBI delivered with a fluid-percussion device. The experimental group (n = 10) received ethanol (3.5 gm/kg) via gastric tube followed in 1 h by TBI. Two groups of control animals received normal saline and TBI (n = 10) or ethanol and no TBI (n = 5). Mean arterial blood pressure (MAP), intracranial pressure (ICP), arterial blood gases, and serum lactate were monitored for 3 h after the injury. CBF was measured with radiolabelled 15-micron diameter microspheres. Neuropathologic changes were evaluated and graded after formalin perfusion and brain removal at 3 h postinjury. The ethanol level 60 min post-head injury was 198 +/- 70 (SD) mg/dL in the ethanol+TBI group. At 90 min postinjury and thereafter, ethanol+TBI animals compared with TBI only animals had significantly lower MAP (63 +/- 26 mmHg vs 91 +/- 15 mmHg) and lower cerebral perfusion pressure (50 +/- 25 mmHg vs 78 +/- 15), and at 180 min postinjury, lower CBF (87 +/- 37% vs 62 +/- 79% of preinjury levels). Ethanol+TBI animals had higher blood lactates (28 +/- 11 mg/dL vs 13 +/- 6 mg/dL) than TBI only animals. Ethanol+TBI animals also had significantly longer postinjury apneas (11 +/- 8 min vs 0.6 +/- 0.4 min), with three of ten ethanol-treated animals never recovering spontaneous respiration. Ethanol intoxication produced hemodynamic and respiratory changes, which may have a deleterious effect on outcome and mortality after brain injury.

Protracted metabolic acidosis: the impact of acute ethanol in hemorrhagic shock

The effects of acute ethanol administration on acid-base balance and hemodynamic parameters were studied in a canine model. Ten mongrel dogs, anesthetized and maintained on a volume ventilator, underwent splenic artery ligation 30 minutes prior to study. Group A (N = 5) served as controls. Thirty minutes after drug administration, the animals underwent a 20-cc/kg hemorrhage over 15 minutes. Thirty minutes postphlebotomy, resuscitation was performed with the same volume of homologous blood. Acid-base and hemodynamic parameters were monitored over 3.5 hours. Ethanol levels peaked 60 minutes following administration at 207 +/- 13 mg%. During the entire study, no differences were observed in heart rate, pulmonary capillary wedge pressure, systemic vascular resistance index, pO2, or pCO2, between the two groups. Following hemorrhage, statistically significant decreases in pH, mean arterial pressure (MAP), cardiac index (CI), and left ventricular stroke work index (LVSWI) developed in group A compared to controls. Maximal disparity developed in pH (7.21 +/- 0.05 to 7.33 +/- 0.02, P < 0.01), MAP (67 +/- 11 v 110 +/- 9 torr, P < 0.01), CI (1.69 +/- 0.24 compared to 2.72 +/- 0.19 L/min/M2, and LVSWI (18.7 +/- 1.2 compared to 44.9 +/- 4.8 gr-meter/M2/beat, P < 0.01) at 60, 45, 30, and 75 minutes postphlebotomy. In this study, ethanol directly or indirectly caused an increased metabolic acidosis and myocardial depression in the post-hemorrhage period.

Base deficit as an indicator of significant abdominal injury

OBJECTIVE

To determine the relative predictive value of the arterial base deficit (BD) as an indicator of intra-abdominal injury (AI) and to compare BD with other indicators (chest injuries, pelvic fractures) of AI.

DESIGN

Retrospective case-control analysis.

SETTING

University of California San Diego Medical Center.

MEASUREMENTS AND MAIN RESULTS

Between January 1985 and July 1988, 3,223 blunt trauma patients were admitted, with complete records available on 3,011. Using a "best fit" multiple logistic regression, BD less than or equal to -6 was the single most important indicator of AI (P less than or equal to .0001), and the odds ratio for AI increased with each category of increasing severity of BD. Admission hypotension, major chest injury, pelvic fracture, and field hypotension (in odds ratio order) also were significantly associated with AI.

CONCLUSION

BD is a powerful indicator of AI. A normal BD does not exclude AI, but the presence of a BD less than or equal to -6 in a blunt trauma patient should be considered a strong indication for objective evaluation of the abdomen (ie, diagnostic peritoneal lavage).

Impact of acute alcohol intoxication on the severity of injury: a cause-specific analysis of non-fatal trauma

The impact of alcohol on the severity of injury was studied by using injured patients from an emergency room in Helsinki, Finland. Blood alcohol content was estimated either clinically or with a breath test and then was recorded using a three-grade intoxication code (Ethyl sign). The study population was comprised of 14,995 men aged 15-64 years. The Ethyl sign was positive in 19.7 per cent. Hospitalization was used as an indicator of the severity of injury. Hospitalization was almost as common among sober (9.3 per cent) as among intoxicated patients (9.6 per cent) and the odds of being hospitalized, if considered 1.0 among the sober, was 1.03 among the intoxicated. However, the severity of injury correlated positively with the alcohol intoxication in the injured car occupants with an odds ratio (OR) of 3.1 (95 per cent confidence interval (CI) 1.7-5.6) and in those injured in falls from stairs (OR = 2.6; 95 per cent CI 1.4-4.7), but negatively in those injured in unspecified falls on the same level (OR = 0.3; 95 per cent CI 0.2-0.6). The effect of alcohol on injury severity seems to vary with the cause of injury.

Effects of acute alcohol intake on tolerance to hypotension

The specific aim of this research was to test the hypothesis that intoxication with alcohol results in poor tolerance to hemorrhage. This was evaluated on the basis of blood pressure, cardiac output respiratory rate, blood flow to organs, and survival for 4 hr after hemorrhage. Four groups of six swine per group were used (control, intoxicated, hemorrhage, and intoxicated-hemorrhage). The results revealed that blood alcohol concentrations near 0.1% greatly reduced tolerance to hemorrhage. Intoxicated animals subjected to hemorrhage were unable to maintain an adequate cardiac output, blood pressure, or respiratory rate to sustain life. Pigs tolerated higher blood alcohol concentrations, up to 0.35%, when not exposed to hemorrhage. Also, unintoxicated pigs were able to compensate for severe hemorrhage. Only one of the six pigs in the intoxicated-hemorrhage group survived for 4 hr after hemorrhage. In conclusion the body's ability to compensate and recover from hemorrhage was greatly reduced during intoxication. It is logical to assume that the ability to overcome numerous other stressors may also be reduced during intoxication.

Effect of alcohol consumption on outcome of pedestrian victims

The influence of alcohol consumption on the severity of pedestrian injuries has not been studied extensively. In this retrospective study, we reviewed the cases of 143 pedestrian accident victims admitted to our trauma center during 1982 and 1983. Alcohol consumption was present in 30% of patients; 74% of them had blood alcohol levels of more than 100 mg/dL. There was a significant difference in age distribution (P less than .001); the alcohol-related accidents peaked in the 25- to 34-year-old age group, and the nonalcohol-related accidents peaked in the less than 18- and more than 55-year-old groups. Mean Injury Severity Score (25.0 vs 17.8, P less than .01) and mean length of stay (30.9 vs 17.2 days, P less than .005) were significantly greater in the patients who had consumed alcohol. Those patients with ethanol in their blood had significantly more frequent injuries to the spine (25.6% vs 10%, P less than .05) and the chest (32.6% vs 13%, P = .01). Overall mortality (11.6% vs 20%, P = .23) and mortality excluding emergency department deaths (11.6% vs 11.1%, P = .93) were not significantly different between the drinking and nondrinking groups. However, the ED mortality was higher in the nonalcohol group (0% vs 10%, P = .03). We conclude that pedestrian victims are commonly intoxicated and that chest and spine injuries are more common in this population.