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BACKGROUND: The Injury Severity Score (ISS) is widely used as a method for rating severity of injury. The ISS is the sum of the squares of the three worst Abbreviated Injury Scale (AIS) values from three body regions. Patients with penetrating injuries tend to have higher mortality rates for a given ISS than patients with blunt injuries. This is thought to be secondary to the increased prevalence of multiple severe injuries in the same body region in patients with penetrating injuries, which the ISS does not account for. We hypothesized that the mechanism-based difference in mortality could be attributed to certain ISS ranges and specific AIS values by body region. METHODS: Outcome and injury scoring data were obtained from transfused patients admitted to 23 Level I trauma centers. ISS values were grouped into categories, and a logistic regression model was created. Mortality for each ISS category was determined and compared with the ISS 1 to 15 group. An interaction term was added to evaluate the effect of mechanism. Additional logistic regression models were created to examine each AIS category individually. RESULTS: There were 2,292 patients in the cohort. An overall interaction between ISS and mechanism was observed (p = 0.049). Mortality rates between blunt and penetrating patients with an ISS between 25 and 40 were significantly different (23.6 vs. 36.1%; p = 0.022). Within this range, the magnitude of the difference in mortality was far higher for penetrating patients with head injuries (75% vs. 37% for blunt) than truncal injuries (26% vs. 17% for blunt). Penetrating trauma patients with an AIS head of 4 or 5, AIS abdomen of 3, or AIS extremity of 3 all had adjusted mortality rates higher than blunt trauma patients with those values. CONCLUSION: Significant differences in mortality between blunt and penetrating trauma patients exist at certain ISS and AIS category values. The mortality difference is greatest for head injured patients. Language: en

Background Significant differences in outcomes have been demonstrated between Level I trauma centers. Usually these differences are ascribed to regional or administrative differences, although the influence of variation in clinical practice is rarely considered. This study was undertaken to determine whether differences in early mortality of patients receiving a massive transfusion (MT, ≥ 10 units pf RBCs within 24 hours of admission) persist after adjustment for patient and transfusion practice differences. We hypothesized differences among centers in 24-hour mortality could predominantly be accounted for by differences in transfusion practices as well as patient characteristics. Methods Data were retrospectively collected over a 1-year period from 15 Level I centers on patients receiving an MT. A purposeful variable selection strategy was used to build the final multivariable logistic model to assess differences between centers in 24-hour mortality. Adjusted odds ratios for each center were calculated. Results : There were 550 patients evaluated, but only 443 patients had complete data for the set of variables included in the final model. Unadjusted mortality varied considerably across centers, ranging from 10% to 75%. Multivariable logistic regression identified injury severity score (ISS), abbreviated injury scale (AIS) of the chest, admission base deficit, admission heart rate, and total units of RBC transfused, as well as ratios of plasma:RBC and platelet:RBC to be associated with 24-hour mortality. After adjusting for severity of injury and transfusion, treatment variables between center differences were no longer significant. Conclusions In the defined population of patients receiving an MT, between-center differences in 24-hour mortality may be accounted for by severity of injury as well as transfusion practices.

Background: The effect of blood component ratios on the survival of patients with traumatic brain injury (TBI) has not been studied. Methods: A database of patients transfused in the first 24 hours after admission for injury from 22 Level I trauma centers over an 18-month period was queried to find patients who (1) met different definitions of massive transfusion (5 units red blood cell [RBC] in 6 hours vs. 10 units RBC in 24 hours), (2) received high or low ratios of platelets or plasma to RBC units (1:2 vs. /=1:2), and (3) had severe TBI (head abbreviated injury score /=3) (TBI+). Results: Of 2,312 total patients, 850 patients were transfused with /= 5 RBC units in 6 hours and 807 could be classified into TBi+ (n = 281) or TBI- (n = 526). Six hundred forty-three patients were transfused with /=10 RBC units in 24 hours with 622 classified into TBI+ (n = 220) and TBi- (n = 402). For both high-risk populations, a high ratio of platelets:RBCs (not plasma) was independently associated with improved 30-day survival for patients with TBI+ and a high ratio of plasma:RBCs (not platelets) was independently associated with improved 30-day survival in TBI- patients. Conclusions: High platelet ratio was associated with improved survival in TBI+ patients while a high plasma ratio was associated with improved survival in TBI- patients. Prospective studies of blood product ratios should include TBI in the analysis for determination of optimal use of ratios on outcome in injured patients.

Background: Improvements in prehospital care and resuscitation have led to increases in the number of severely injured patients who are salvageable. Massive transfusion has been increasingly used. Patients often present with markedly abnormal physiologic and biochemical data. The purpose of this study was to identify objective data that can be used to identify clinical futility in massively transfused trauma patients to allow for early termination of resuscitative efforts. Methods: A multicenter database was used. Initial physiologic and biochemical data were obtained, and mortality was determined for patients in the 5th and 10th percentiles for each variable. Raw data from the extreme outliers for each variable were also examined to determine whether a point of excessive mortality could be identified. Injury scoring data were also analyzed. A classification tree model was used to look for variable combinations that predict clinical futility. Results: The cohort included 704 patients. Overall mortality was 40.2%. The highest mortality rates were seen in patients in the 10th percentile for lactate (77%) and pH (72%). Survivors at the extreme ends of the distribution curves for each variable were not uncommon. The classification tree analysis failed to identify any biochemical and physiologic variable combination predictive of 90% mortality. Patients older than 65 years with severe head injuries had 100% mortality. Conclusion: Consideration should be given to withholding massive transfusion for patients older than 65 years with severe head injuries. Otherwise we did not identify any objective variables that reliably predict clinical futility in individual cases. Significant survival rates can be expected even in patients with profoundly abnormal physiologic and biochemical data.

BACKGROUND Several recent military and civilian trauma studies demonstrate that improved outcomes are associated with early and increased use of plasma-based resuscitation strategies. However, outcomes associated with platelet transfusions are poorly characterized. We hypothesized that increased platelet:red blood cells (RBC) ratios would decrease hemorrhagic death and improve survival after massive transfusion (MT). METHODS A transfusion database of patients transported from the scene to 22 Level I Trauma Centers over 12 months in 2005 to 2006 was reviewed. MT was defined as receiving ≥ 10 RBC units within 24 hours of admission. To mitigate survival bias, 25 patients who died within 60 minutes of arrival were excluded from analysis. Six random donor platelet units were considered equal to a single apheresis platelet unit. Admission and outcome data associated with the low (>1:20), medium (1:2), and high (1:1) platelet:RBC ratios were examined. These groups were based on the median value of the tertiles for the ratio of platelets:RBC units. RESULTS Two thousand three hundred twelve patients received at least one unit of blood and 643 received an MT. Admission vital signs, INR, temperature, pH, Glasgow Coma Scale, Injury Severity Score, and age were similar between platelet ratio groups. The average admission platelet counts were lower in the patients who received the high platelet:RBC ratio versus the low ratio (192 vs. 216, p = 0.03). Patients who received MT were severely injured, with a mean (± standard deviation) Injury Severity Score of 33 ± 16 and received 22 ± 15 RBCs and 11 ± 14 platelets within 24 hours of injury. Increased platelet ratios were associated with improved survival at 24 hours and 30 days (p < 0.001 for both). Truncal hemorrhage as a cause of death was decreased (low: 67%, medium: 60%, high: 47%, p = 0.04). Multiple organ failure mortality was increased (low: 7%, medium: 16%, high: 27%, p = 0.003), but overall 30-day survival was improved (low: 52%, medium: 57%, high: 70%) in the high ratio group (medium vs. high: p = 0.008; low vs. high: p = 0.007). CONCLUSION Similar to recently published military data, transfusion of platelet:RBC ratios of 1:1 was associated with improved early and late survival, decreased hemorrhagic death and a concomitant increase in multiple organ failure-related mortality. Based on this large retrospective study, increased and early use of platelets may be justified, pending the results of prospective randomized transfusion data.

Background: Administration of high transfusion ratios in patients not requiring massive transfusion might be harmful. We aimed to determine the effect of high ratios of fresh frozen plasma (FFP) and platelets (PLT) to packed red blood cells (PRBC) in nonmassively transfused patients. Methods: Records of 1,788 transfused trauma patients who received 10 units of PRBC in 24 hours at 23 United States Level I trauma centers were reviewed. The relationship between ratio category (low and high) and in-hospital mortality was assessed with propensity-adjusted multivariate proportional hazards models. Results: At baseline, patients transfused with a high FFP:PRBC ratio were younger, had a lower Glasgow Coma Scale score, and a higher Injury Severity Score. Those receiving a high PLT:PRBC ratio were older. The risk of in-hospital mortality did not vary significantly with FFP:PRBC ratio category. Intensive care unit (ICU)-free days, hospital-free days, and ventilator-free days did not vary significantly with FFP:PRBC ratio category. ICU-free days and ventilator-free days were significantly decreased among patients in the high (1:1) PLT:PRBC category, and hospital-free days did not vary significantly with PLT:PRBC ratio category. The analysis was repeated using 1:2 as the cutoff for high and low ratios. Using this cutoff, there was still no difference in mortality with either FFP:PRBC ratios or platelet:PRBC ratios. However, patients receiving a 1:2 ratio of FFP: PRBCs or a 1:2 ratio PLT:PRBCs had significantly decreased ICU-free days and ventilator-free days. Conclusions: FFP:PRBC and PLT:PRBC ratios were not associated with in-hospital mortality. Depending on the threshold analyzed, a high ratio of FFP:PRBC and PLT:PRBC transfusion was associated with fewer ICU-free days and fewer ventilator-free days, suggesting that the damage control infusion of FFP and PLT may cause increased morbidity in nonmassively transfused patients and should be rapidly terminated when it becomes clear that a massive transfusion will not be required.

To evaluate the role of nonoperative management in the treatment of blunt liver trauma we examined all victims of blunt hepatic trauma admitted to our institution during a 36-month period under a protocol of nonoperative management. One hundred twenty-six patients had the diagnosis of blunt hepatic injury confirmed by abdominal computed tomographic (CT) scanning, surgical exploration, or autopsy. Twenty-four patients went to the operating room without CT scanning because of hemodynamic instability (16), peritoneal signs (two), or positive results on DPL (six). Ten other patients died of extra-abdominal trauma before reaching the operating room. The remaining 92 patients had CT scans of the abdomen. Of these 92 patients, 20 required surgery. The indications for surgery were hemodynamic instability (seven), peritoneal signs (six), nonhepatic injuries requiring surgery (five), and massive hemoperitoneum (two). Seventy-two patients were intentionally managed nonoperatively (55% of total liver injuries, 78% of scanned patients). Seventy (97%) of these patients were managed successfully without surgery. Of these 72 liver injuries, 11 were grade I, 28 were grade II, 16 were grade III, ten were grade IV, and five were grade V. The transfusion requirement in the first 24 hours for the nonoperative group was significantly lower than that for the group undergoing surgery (1.2 +/- 1.7 vs. 12.2 +/- 14 units). There were no instances of hemobilia, intrahepatic bile collections, or abdominal abscess in the nonoperative group. The grade of hepatic injury as diagnosed by CT scan does not predict the need for surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

BACKGROUND Recent data suggest that massively transfused patients have lower mortality rates when high ratios (>1:2) of plasma or platelets to red blood cells (RBCs) are used. Blunt and penetrating trauma patients have different injury patterns and may respond differently to resuscitation. This study was performed to determine whether mortality after high product ratio massive transfusion is different in blunt and penetrating trauma patients. METHODS Patients receiving 10 or more units of RBCs in the first 24 hours after admission to one of 23 Level I trauma centers were analyzed. Baseline physiologic and biochemical data were obtained. Univariate and logistic regression analyses were performed. Adjusted mortality in patients receiving high (≥ 1:2) and low (

BACKGROUND Recent data suggest that patients undergoing massive transfusion have lower mortality rates when ratios of plasma and platelets to red blood cells (RBCs) of ≥ 1:2 are used. This has not been examined independently in women and men. A gender dichotomy in outcome after severe injury is known to exist. This study examined gender-related differences in mortality after high product ratio massive transfusion. METHODS A retrospective study was conducted using a database containing massively transfused trauma patients from 23 Level I trauma centers. Baseline demographic, physiologic, and biochemical data were obtained. Univariate and logistic regression analyses were performed. Adjusted mortality in patients receiving high (≥ 1:2) or low (

Current trauma resuscitation guidelines recommend giving an initial crystalloid bolus as first line for resuscitation. Recent studies have shown a survival benefit for trauma patients resuscitated with high ratios of fresh frozen plasma (FFP) to packed red blood cells (PRBC). Our aim was to determine whether the volume of crystalloid given during resuscitation correlated with differences in morbidity or mortality based on the ratio of FFP:PRBC given.This was a retrospective review of 2,473 transfused trauma patients at 23 Level I trauma centers from July 2005 to October 2007. Patients were separated based on the ratios of FFP:PRBC they received (1:4, 1:4-1:1, and1:1) and then analyzed for morbidity and mortality based on whether or not they received at least 1 L crystalloid for each unit of PRBC. Outcomes analyzed were 6-hour, 24-hour, and 30-day survival as well as intensive care unit (ICU)-free days, ventilator-free days, and hospital-free days.Massive transfusion patients who received1:4 ratios of FFP:PRBC had significantly improved 6-hour, 24-hour, and 30-day mortality and significantly more ventilator-free days if they received at least 1 L of crystalloid for each unit of PRBC. Nonmassive transfusion patients who received1:4 ratios of FFP:PRBC had significantly improved 6-hour, 24-hour, and 30-day mortality and significantly more ICU-free days, ventilator-free days, and hospital-free days if they received at least 1 L crystalloid for each unit of PRBC. In both massive and nonmassive transfusion groups, the survival benefit and morbidity benefit was progressively less for the 1:4 to 1:1 FFP:PRBC groups and1:1 FFP:PRBC groups.If high ratios of FFP:PRBC are unable to be given to trauma patients, resuscitation with at least 1 L of crystalloid per unit of PRBC is associated with improved overall mortality.

Background Improvements in trauma systems and resuscitation have increased survival in severely injured patients. Massive transfusion has been increasingly used in the civilian setting. Objective predictors of mortality have not been well described. This study examined data available in the early postinjury period to identify variables that are predictive of 24-hour- and 30-day mortality in massively transfused trauma patients. Methods Massively transfused trauma patients from 23 Level I centers were studied. Variables available on patient arrival that were predictive of mortality at 24 hours were entered into a logistic regression model. A second model was created adding data available 6 hours after injury. A third model evaluated mortality at 30 days. Receiver operating characteristic curves and the Hosmer-Lemeshow test were used to assess model quality. Results Seven hundred four massively transfused patients were analyzed. The model best able to predict 24-hour mortality included pH, Glasgow Coma Scale score, and heart rate, with an area under the receiver operating characteristic curve (AUROC) of 0.747. Addition of the 6-hour red blood cell requirement increased the AUROC to 0.769. The model best able to predict 30-day mortality included the above variables plus age and Injury Severity Score with an AUROC of 0.828. Conclusion Glasgow Coma Scale score, pH, heart rate, age, Injury Severity Score, and 6-hour red blood cell transfusion requirement independently predict mortality in massively transfused trauma patients. Models incorporating these data have only a modest ability to predict mortality and should not be used to justify withholding massive transfusion in individual cases.

Abdominal CT, which routinely includes the lower thorax, is an important adjunct to supine chest radiography in detecting chest injury in patients with blunt abdominal trauma. In 1,086 consecutive patients with blunt abdominal trauma, 223 of whom had both supine chest radiography and abdominal CT, 49 patients examined with both techniques had pneumothoraces, 28 of them occult (seen only on CT). To help guide management, we established three categories of occult pneumothorax, based on size and location: (a) minuscule (1 cm in greatest thickness, seen on four or fewer images); (b) anterior (1 cm in greatest thickness, but not extending beyond the midcoronal line); (c) anterolateral (extending beyond the midcoronal line). In our study four of six patients with minuscule pneumothorax, including one who required mechanical ventilation, were observed without complications; two of six patients had chest tube placement. Seven of 14 cases with anterior pneumothorax were observed and resolved without complication; seven had chest tube placement. All eight patients with anterolateral pneumothoraces underwent percutaneous tube thoracostomy, regardless of proposed management.

In some populations, intensive care unit (ICU) mobility has been shown to be safe and beneficial. We gathered data on 50 nonintubated surgical patients in a 10-bed surgical ICU (SICU) who met physiologic inclusion criteria beginning in May 2008 (A group). In January 2009, we began mandatory entry of computerized mobility orders as part of a standardized ICU order set. We also created a mobility protocol for nurses in this ICU. We then collected data on 50 patients in this postintervention cohort (B group). Both groups had similar baseline characteristics. A group patients had some form of mobility orders entered in 29 patients (58%) versus 47 patients (82%) in the B group, P0.05. In the A group, 11 patients (22%) were mobilized; in the B group, 40 patients (80%) were mobilized, P0.05. In our SICU patient population, mandatory entry of computerized mobility orders as part of a standard SICU order set and establishment of an ICU mobility nursing protocol was associated with an increase in number of mobility orders entered as well as an increase in SICU patient activity. Further studies should focus on measurement of the effect of mobility interventions on patient outcomes.

CT is the technique of choice for initial examination of hemodynamically stable patients after blunt abdominal trauma. It is highly sensitive, specific, and accurate for use in detecting the presence or absence of injury and defining its extent. Nonoperative management of many posttraumatic injuries, particularly in the liver, spleen, and kidney, is possible in part because of the diagnostic usefulness of CT. CT can be used effectively to visualize the progression of liver and spleen injuries in those patients chosen for conservative management. CT helps in treatment decisions in patients with renal injury by defining the character and extent and distinguishing minor from severe renal trauma. Posttraumatic injuries to the pancrease, bowel, and mesentery can be detected with CT. In these areas, however, signs may be subtle, and a significant injury may be missed on an initial examination.

Background: Bleeding pelvic fractures (BPF) carry mortality as high as 60%, yet controversy remains over optimal initial management. Some base initial intervention on fracture pattern, with immediate external fixation (EX FIX) in amenable fractures aimed at controlling venous bleeding. Others feel ongoing hemodynamic instability indicates arterial bleeding, and prefer early angiography (ANGIO) before EX-FIX. Our aim was to evaluate markers of arterial bleeding in patients with BPF, thus identifying patients requiring early ANGIO regardless of fracture pattern. Methods: Patients with pelvis fracture were identified from a Level I trauma center registry over a 7-year period and records reviewed. From this group, two subsets were analyzed: those with initial hypotension related to pelvic fracture, and those without hypotension who underwent pelvic ANGIO. Data included hemodynamics, response to resuscitation, presence of contrast blush on CT, fracture treatment and outcome. Adequate response to initial resuscitation (R) was defined as a sustained (>2 hours) improvement of systolic blood pressure to >90 mm Hg systolic after the administration of ≤2 units packed red blood cells. Those with repeated episodes of hypotension despite resuscitation were classified as non-responders (NR) Results: From 1/94-1/01, 1171 patients were admitted with pelvic ring fracture. Thirty-five (0.3%) had hypotension attributable to pelvis fracture. 28 fell into the NR group, and 26 of these underwent ANGIO. Nineteen (73%) showed arterial bleeding while 3 resuscitation response patients underwent ANGIO with none demonstrating bleeding (p = 0.03). Sensitivity and specificity of inadequate response to initial resuscitation for predicting the presence of arterial bleeding on ANGIO were 100% and 30% respectively while negative and positive predictive value were 100% and 73%. In patients with fractures amenable to external fixation (n = 16), 44% had arterial bleeding on ANGIO, and all were in the NR group. An additional 17 patients without hypotension also underwent ANGIO. Contrast blush on admission CT was seen in 4, 3 of which had arterial bleeding seen on ANGIO (75%). Sensitivity and specificity for contrast blush in predicting bleeding on ANGIO were 60% and 92% with positive and negative predictive value being 75% and 85%. Conclusions: In patients with hypotension and pelvic fracture, therapy selection based on initial response to resuscitation in BPF yields a 73% positive ANGIO rate in NR patients. Delay in ANGIO for EX FIX in patients with amenable fractures would have delayed embolization in the face of ongoing arterial bleeding in 44% of patients. In stable patients with pelvic fracture, contrast blush also indicates a high likelihood of arterial injury and ANGIO is indicated. Optimal therapy in the face of BPF requires early determination of the presence of arterial bleeding so that ANGIO can be rapidly obtained, and response to initial resuscitation as well as the presence of contrast blush aid in this decision.

Background: The purpose of this study was to examine the contribution of age and gender to outcome after treatment of blunt splenic injury in adults. Methods: Through the Multi-Institutional Trials Committee of the Eastern Association for the Surgery of Trauma (EAST), 1488 adult patients from 27 trauma centers who suffered blunt splenic injury in 1997 were examined retrospectively. Results: Fifteen percent of patients were 55 years of age or older. A similar proportion of patients ≥ 55 went directly to the operating room compared with patients < 55 (41% vs. 38%) but the mortality for patients ≥ 55 was significantly greater than patients < 55 (43% vs. 23%). Patients ≥ 55 failed nonoperative management (NOM) more frequently than patients < 55 (19% vs. 10%) and had increased mortality for both successful NOM (8% vs. 4%, p < 0.05) and failed NOM (29% vs. 12%, p = 0.054). There were no differences in immediate operative treatment, successful NOM, and failed NOM between men and women. However, women ≥ 55 failed NOM more frequently than women < 55 (20% vs. 7%) and this was associated with increased mortality (36% vs. 5%) (both p < 0.05). Conclusion: Patients ≥ 55 had a greater mortality for all forms of treatment of their blunt splenic injury and failed NOM more frequently than patients < 55. Women ≥ 55 had significantly greater mortality and failure of NOM than women < 55.

Optimal guidelines for empiric antibiotic (EAB) therapy in cases of suspected post-traumatic ventilator-associated pneumonia (VAP) are not well defined. EAB administration is thought to increase the incidence of opportunistic organisms; however, culture-directed (as opposed to empiric) treatment may delay antibiotic administration with possible adverse consequences. Our goal was to examine the impact of EAB administration on the incidence of subsequent VAP and opportunistic organisms in a series of critically injured patients with sepsis syndrome. This is a retrospective review of all patients admitted to a Level I trauma center who underwent multiple fiberoptic bronchoscopies (FOBs) for diagnosis of suspected VAP as the cause of postinjury sepsis syndrome. The relationships between EAB administration, positive cultures (10(5) colony-forming units) at repeat FOB, and prevalence of opportunistic organisms (methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, Stenotrophomonas species, Acinetobacter species, and/or yeast) were evaluated. Over a 13-month period ending on January 1, 1999, 36 intubated trauma patients underwent more than one FOB during their intensive care unit stay. Twenty-nine patients received EAB immediately after the initial FOB. There was no difference in the rate of EAB administration in patients who developed subsequent VAP after initial FOB (19 of 24, 79%) versus those who did not develop VAP (10 of 12, 83%; P = 0.65). There were 30 VAPs diagnosed in 58 subsequent FOBs (i.e., after the initial FOB) of which 23 were due to an opportunistic organism compared with two VAPs due to an opportunistic organism diagnosed at initial FOB (P0.001). Twenty-one of the 23 opportunistic VAPs at subsequent FOBs had received EAB before the first FOB compared with four of seven nonopportunistic organisms (P = 0.06). Administration of EAB does not impact the incidence of subsequent VAP. However, EAB may be related to the development of subsequent opportunistic pulmonary infections.

In the setting of blunt trauma, abdominal CT, which routinely includes images of the lower thorax, frequently reveals pneumothoraces that have not been detected on routine supine chest radiographs. Proper management of these occult pneumothoraces remains controversial. The purpose of this study was to test the hypothesis that small (minuscule) to moderate (anterior) radiographically occult pneumothoraces can be safely managed without chest tube placement for patients in whom the need for positive pressure ventilation is not anticipated.We undertook a prospective study in which 44 occult pneumothoraces were classified into three groups, minuscule, anterior, or anterolateral, according to size and location on CT scans. Choice of initial management (tube thoracostomy versus close observation) was based in part on this classification system and in part on individual circumstances of a surgeon's decision.Of the 44 pneumothoraces found in 36 patients, 16 pneumothoraces were minuscule, 20 were anterior, and eight were anterolateral. Thirteen minuscule pneumothoraces and 11 anterior pneumothoraces initially managed with observation did not require subsequent tube thoracostomy. All eight patients with anterolateral pneumothoraces underwent tube thoracostomy.Most small (minuscule) occult pneumothoraces can successfully be managed with close observation. The risk that the pneumothorax will progress is slight. Moderate-sized (anterior) pneumothoraces may also be successfully managed without initial placement of a chest tube if the patient is not to undergo positive pressure ventilation.

Objectives: (1) To compare left ventricular stroke work index (SW) and left ventricular power output (LVP), hemodynamic variables that encompass blood pressure as well as blood flow, with the purely flow-derived hemodynamic and oxygen transport variables as markers of perfusion and outcome in critically injured patients during resuscitation. (2) To use the ventricular pressure-volume diagram to define characteristic hemodynamic patterns in the determinants of SW and LVP that are associated with survival. Methods: This was a cohort study at a university Level I trauma center during the course of I year. A consecutive series of patients was monitored with a volumetric pulmonary artery catheter during the initial 48 hours of resuscitation. Heart rate, SW, LVP, cardiac index, and oxygen delivery and consumption during resuscitation were compared using multivariate logistic regression analysis with regard to the ability to clear lactate in less than 24 hours and survival. Receiver operating characteristic curves were constructed to determine threshold values for SW and LVP. Ventricular pressure-volume diagrams were used to describe characteristic patterns in the determinants of SW and LVP in survivors and nonsurvivors. Preload was expressed as left ventricular end-diastolic volume index, afterload as aortic input impedance (E a ), and contractility as ventricular end-systolic elastance (E es ). The ratio of E a /E es (RATIO) was used as a measure of ventricular-arterial coupling, which describes the efficacy of energy transfer from the heart to the vascular system. Results: One hundred eleven patients (87 survivors, 24 nonsurvivors) met study criteria. Survivors had a significantly higher SW (4,510 ± 1,070 vs. 3,440 ± 980 mm Hg.mL.m -2 ; p < 0.0001) and LVP (370 ± 94 vs. 270 ± 81 mm Hg.L.min -1 .m -2 ; p < 0.0001) than nonsurvivors. Heart rate, SW, and LVP were the only studied variables that were significantly related to lactate clearance and survival by logistic regression. Threshold values determined by the receiver operating characteristic curves were 4,000 mm Hg.mL.m -2 for SW and 320 mm Hg.L.min -1 .m -2 for LVP. Survivors had better ventricular-arterial coupling than nonsurvivors, indicated by a lower RATIO (0.32 ± 0.22 vs. 0.54 ± 0.38; p = 0.003). This lower RATIO was attributable to lower levels of E a (2.7 ± 0.7 vs. 3.4 ± 0.8 mm Hg.mL -1 .m -2 ; p = 0.0003) and a trend toward higher levels of E es (13 ± 11 vs. 9.9 ± 7.3 mm Hg.mL -1 .m -2 ; p = 0.12). Conclusion: Thermodynamic perfusion variables that encompass both pressure and flow, such as SW and LVP, are more closely related to perfusion and outcome than the purely flow-derived variables. The higher SW and LVP in survivors is related to better ventricular-arterial coupling, and therefore more efficient cardiac function. Cutoff values for LVP of 320 mm Hg.L.min -1 .m -2 and for SW of 4,000 mm Hg.mL.m -2 may be useful thresholds for evaluating hemodynamic performance during resuscitation.

OBJECTIVE: Clinical pathways now highlight both observation and operation as acceptable initial therapeutic options for the management of patients with splenic injury. The purpose of this study was to evaluate treatment trends for splenic injury in all North Carolina trauma centers over a 6-year period. METHODS: Splenic injuries in adults over a 6-year period (January 1988-December 1993) were identified in the North Carolina Trauma Registry using ICD-9-CM codes. Patients were divided into four groups by method of management: 1) no spleen operation, 2) splenectomy, 3) definitive splenorrhaphy, and 4) splenorrhaphy failure followed by splenectomy. The authors examined age, mechanism of injury, admitting blood pressure, and severity of injury by trauma score and injury severity score. SUMMARY BACKGROUND DATA: Comparisons were made between adult (17-64 years of age) and geriatric (older than 65 years of age) patients and between patients with blunt and penetrating injury. Resource utilization (length of stay, hospital charges) and outcome (mortality) were compared. RESULTS: One thousand two hundred fifty-five patients were identified with splenic injury. Rate of splenic preservation increased over time and was achieved in more than 50% of patients through nonoperative management (40%) and splenorrhaphy (12%). Splenorrhaphy was not used commonly in either blunt or penetrating injury. Overall mortality was 13%. Geriatric patients had a higher mortality and resource utilization regardless of their mechanism of injury or method of management. CONCLUSIONS: Nonoperative management represents the prevailing method of splenic preservation in both the adult and geriatric population in North Carolina trauma center hospitals. Satisfactory outcomes and economic advantages accompany nonoperative management in this adult population. Language: en

A canine model was used to investigate the efferent laryngeal responses to stimulation by topically applied acid and pepsin. Five adult mongrel dogs were studied. Electromyographic recordings from the thyroarytenoid muscle were measured with hooked-wire electrodes as an acid solution (normal saline/hydrochloric acid at pH 6.0, 5.0, 4.0, 3.0, 2.5, 2.0, 1.5, and 1.0) was sequentially instilled into the larynx. Laryngospasm (tonic, sustained contraction of the thyroarytenoid muscle) occurred in all animals at pH 2.5 to 2.0 or less. Control substances such as neutral pH isotonic saline, hypotonic saline, hypertonic saline, water, and pepsin alone failed to produce laryngospasm. Next, solutions containing both acid (in the same pH range) and pepsin were tested. The laryngeal responses were similar to those of acid alone. The superior laryngeal nerves were sectioned bilaterally and the above experiments repeated. None of the test solutions produced laryngospasm; however, when capsaicin (1%) was instilled into the subglottis, laryngospasm occurred. Thus, chemoreceptors in the subglottis (supplied by the recurrent laryngeal nerves) appear to be responsive to capsaicin stimulation but not to acid stimulation. The data suggest that pH-sensitive chemoreceptors in the canine larynx cause laryngospasm (when the pH of the test solution is 2.5 or less) and that these acid receptors are supplied by the superior laryngeal nerves.

HYPOTHESIS: Emergency cesarean sections in trauma patients are not justified and should be abandoned. SETTING AND DESIGN: A multi-institutional, retrospective cohort study was conducted of level 1 trauma centers. METHODS: Trauma admissions from nine level 1 trauma centers from January 1986 through December 1994 were reviewed. Pregnant women who underwent emergency cesarean sections were identified. Demographic and clinical data were obtained on all patients undergoing a cesarean section. Fetal distress was defined by bradycardia, deceleration, or lack of fetal heart tones (FHTs). Maternal distress was defined by shock (systolic blood pressure < 90) or acute decompensation. Statistical analyses were performed. RESULTS: Of the 114,952 consecutive trauma admissions, more than 441 pregnant women required 32 emergency cesarean sections. All were performed for fetal distress, maternal distress, or both. Overall, 15 (45%) of the fetuses and 23 (72%) of the mothers survived. Of 33 fetuses delivered, 13 had no FHTs and none survived. Twenty infants (potential survivors) had FHTs and an estimated gestational age (EGA) of greater than or equal to 26 weeks, and 75% survived. Infant survival was independent of maternal distress or maternal Injury Severity Score. The five infant deaths in the group of potential survivors resulted from delayed recognition of fetal distress, and 60% of these deaths were in mothers with mild to moderate injuries (Injury Severity Score < 16). CONCLUSIONS: In pregnant trauma patients, infant viability is defined by the presence of FHTs, estimated gestational age greater than or equal to 26 weeks. In viable infants, survival after emergency cesarean section is acceptable (75%). Infant survival is independent of maternal distress or Injury Severity Score. Sixty percent of infant deaths resulted from delay in recognition of fetal distress and cesarean section. These were potentially preventable. Given the definition of fetal viability, our initial hypothesis is invalid.

To describe the epidemiology of nosocomial pneumonia in trauma patients and its impact on outcome, we performed a retrospective case-control analysis. Quantitative bronchoscopic cultures were collected from 62 intubated patients with suspected pneumonia. Patients with proven pneumonia had higher abdominal injury scores. Those with bronchoscopy-negative pneumonitis were older. Age and injury severity were used to match two controls to each case. The incidence of pneumonia was 5.8% Streptococci and Hemophilus were common pathogens, but gram-negative rods were isolated more frequently after lengthier intubation. Polymicrobial infections were common. There were no serious complications of bronchoscopy, and culture results often led to antibiotic therapy. No excess mortality could be attributed to pneumonia. Patients with pneumonia and those with bronchoscopy-negative pneumonitis required prolonged care compared with others (p < 0.05). Patients with pneumonia did not receive excess ventilation or hospitalization but incurred hospital charges 1.5 times higher than controls (p = 0.04). Pneumonia was confirmed in less than half of those suspected of having it on the basis of clinical findings. When severity of injury was considered, pneumonia was associated with neither increased mortality nor increased hospital care, but the clinical features suggesting respiratory infection identified trauma patients requiring prolonged hospitalization and incurring higher costs.

There is concern that oxygen delivery-directed resuscitation in patients with multiple trauma, including severe head injury, may worsen neurologic recovery. To study this, we retrospectively examined 31 patients admitted over an 18-month period who met the inclusion criteria of having suffered blunt trauma, were between 15 and 65 years of age, had an admission Glasgow coma scale ofor = 8, intact corneal and gag reflexes, and extracranial injury with an Abbreviated Injury score ofor = 3. All patients were placed on intracranial pressure monitors. In comparing the 14 patients whose resuscitation was guided by oxygen delivery (DO2) with the 17 who were resuscitated by standard fluid restriction (FR), we found that despite the DO2 group's having received a significantly greater volume of resuscitation fluids in the first 48 hours after injury, there was no difference in the neurologic recovery between the two groups.

A state trauma registry database containing 13,834 patients was evaluated to determine the relationship among 1,062 skull fractures, 1,329 facial fractures, 339 cervical spine injuries, and 299 spinal cord injuries. Categories studied were all trauma patients, motor vehicle crashes, automobile crashes (drivers, passengers, unknown), and belted and unbelted victims. Odds ratios calculated demonstrated that patients with skull and/or facial fractures did not have a higher likelihood of cervical spine or spinal cord injury as has been suggested. The lack of a relationship emphasizes the need for a greater vigilance for cervical spine and spinal cord injury in the group without facial or skull fractures. It appears that the pathological biomechanical forces causing each injury are a reflection of the different multiple forces associated with motor vehicle trauma.

Pulmonary embolism is a potentially lethal complication among patients with acetabular fractures requiring surgery. The reliability, safety, and extent of efficacy of pharmacologic as well as existing nonpharmacologic anticoagulation prophylaxis in this patient group has not been determined. A careful analysis of the myriad factors acting on these patients who have had major trauma and have undergone a major surgical procedure about the hip prompted a change in our approach to prophylaxis in this patient group. In the period from March 1984 through October 1987, 51 patients having 52 acetabular fractures underwent osteosynthesis at the Wake Forest University Medical Center. Twenty-four patients had two or more identifiable risk factors and underwent insertion of a Greenfield filter for prevention of pulmonary emboli. Filters were inserted at the time of acetabular surgery with C-arm guidance via the internal jugular vein approach. The average time for insertion was 57 min. Placements were verified by plain roentgenograms. There were no complications during filter insertion. Four patients with filters (17%) developed leg edema: in three the edema was minor, and in one the filter trapped what could have been a fatal embolus but caused lower extremity venous stasis severe enough to result in peripheral lower extremity tissue loss. There were no pulmonary emboli (by clinical criteria). The remaining 27 patients had routine medical prophylaxis and no filters. In this group, two patients had a clinically evident pulmonary embolus (7%), and one of these patients died. Two other patients (7%) had minor chronic leg edema. In one of them, a proximal deep venous thrombosis in the lower extremity was documented with venography, requiring rehospitalization and anticoagulant therapy. We conclude that the Greenfield filter is an efficacious method for preventing lethal pulmonary emboli in this high-risk patient group. Short-term and intermediate-term morbidity is minimal.

Early enteral nutrition may preserve gut function and prevent bacterial translocation after trauma. Standard enteral nutrition uses products which contain intact protein and require digestion for absorption. Peptide-based enteral nutritional products are better absorbed and stimulate the release of gut trophic hormones. This study was performed to determine whether a peptide-based (PEP) product (Reabilan HN) was better tolerated and/or produced better hepatic protein responses in patients after trauma when compared to an intact-protein (PRO) formula (Osmolite HN). Eighteen trauma patients were prospectively randomized to PEP (n = 9) or PRO (n = 9) enteral diets administered via nasoduodenal tubes (within 1-2 days of injury). Visceral protein synthesis was assessed by measuring baseline and 1 week pre-albumin and transferrin levels. Diarrhea was defined as greater than 300 gm/day of stool. Groups were similar in age, Injury Severity Score (ISS), caloric intake, and protein intake. Protein levels increased significantly faster in PEP patients despite similar urea nitrogen excretion. Diarrhea developed in four (44%) PRO patients and none of the PEP patients. Three of the PRO patients were switched to PEP after one week and diarrhea subsided in all three patients. Peptide-based enteral diets are associated with better hepatic protein responses and less diarrhea compared to intact-protein diets.

The need for ventricular venting with hypothermic cardioplegic arrest is controversial. We report an evaluation of the need for left ventricular venting in a canine model that closely simulates conditions during routine coronary artery bypass grafting (CABG). Thirty-five dogs were placed on cardiopulmonary bypass for 60 minutes of hypothermic cardioplegic arrest (18 vented, 17 nonvented) and then reperfused for 30 minutes. Myocardial temperature and left atrial pressure (LAP) were recorded continuously. Before and 30 minutes after hypothermic cardioplegic arrest, left ventricular function curves were generated (six vented, six nonvented), and biopsy specimens of the left ventricle were taken for adenosine triphosphate (ATP) determinations (11 vented, 10 nonvented) and semiquantitative grading of mitochondrial ultrastructure (six vented, six nonvented). LAP in nonvented dogs was 7.4 mm Hg during hypothermic cardioplegic arrest and 5.0 mm Hg during reperfusion. Temperature during hypothermic cardioplegic arrest was 12.3 degrees C in vented dogs and 11.3 degrees C in nonvented dogs (p = 0.5). There were no differences in left ventricular function or preservation of mitochondrial ultrastructure between vented and nonvented dogs. ATP after hypothermic cardioplegic arrest was 96.6% of control (4.30 microM/gm) in vented dogs and 94.6% (4.37 microM/gm) in nonvented dogs (p = 0.7). The absence of left ventricular venting did not lead to ventricular distention or more rapid rewarming. These data in vented dogs and nonvented dogs strongly support the belief that left ventricular venting is not necessary during routine CABG.

The pathophysiology of pulmonary inhalation injury, a major cause of morbidity and mortality from fires, is poorly understood. To examine the effects of colloid and crystalloid resuscitation on extravascular lung water (EVLW) during a standard smoke inhalation injury, we subjected 12 sheep to 8 minutes of cool pine smoke inhalation. The animals were then resuscitated to a pulmonary capillary wedge pressure (PCWP) of 10 +/- 1.5 mm Hg with either lactated Ringer's solution or plasma protein derivative. EVLW, cardiac output, vascular resistance, colloid oncotic pressure (COP), arterial and pulmonary artery pressures, PCWP, and blood gases were monitored during 4 hours of resuscitation. In colloid-treated animals, EVLW increased from 8.3 +/- 1.2 to 11.1 +/- 0.9 ml/kg with injury; it increased only to 12.5 +/- 1.3 ml/kg during resuscitation. In crystalloid-treated animals, EVLW increased from 8.0 +/- 1.0 to 10.3 +/- 0.8 ml/kg with injury and further increased to 17.4 +/- 1.6 ml/kg during resuscitation, a level significantly higher than that in the colloid group (P less than 0.05). The increases in EVLW were associated with progressive hypoxia, which was worse in the crystalloid group. In the crystalloid group, COP decreased from 27.3 +/- 0.9 to 14.2 +/- 0.4 mm Hg and intravascular driving force (COP-PCWP) dropped from 17.6 to 3.26 +/- 1.5 mm Hg; COP and COP-PCWP were maintained in the colloid group. These data demonstrate that supporting serum COP minimizes the increase in EVLW with smoke inhalation injury and suggests that smoke inhalation does not lead to a dramatic increase in alveolar capillary membrane permeability to protein.

Despite advances in wound healing, fascial dehiscence continues to be a problem in celiotomy wounds. Experimental and clinical studies on suture material and on patient-related factors in wound disruption are abundant, but little attention has been given to mechanical factors in wound closure, although they may be of greater importance. A midline abdominal wound was made in 120 Harlan Sprague-Dawley rats, and the fascia was closed with Dacron in one of six ways: simple interrupted, interrupted figure-of-eight, and running, each tied loosely in one half of each group and tightly in the other half. One week later, the rats were reanesthetized and wound-bursting strength was measured. In general, the running suture technique resulted in the greatest wound-bursting pressures. A loosely tied figure-of-eight technique was nearly as good as a loosely tied running stitch, but tying figure-of-eight sutures tightly caused a significant decrease in wound-bursting pressure. The simple interrupted technique was unaffected by suture tension but was generally inferior to the running stitch in terms of wound-bursting strength. Histologic studies were performed, but most of the disparity in wound strength among the suture techniques apparently was due solely to mechanical factors. Closing midline abdominal fascial wounds with a running suture may be a superior method of closure in clean, incised wounds.

A midline abdominal wound was made in 135 Harlan Sprague-Dawley rats, and the fascia was then closed by the continuous suture technique with 4-0 absorbable monofilament polydioxanone sutures (n = 45 rats), 4-0 permanent monofilament polypropylene sutures (n = 45 rats), or 4-0 Teflon-coated braided Dacron sutures (n = 45 rats). At 1-, 2-, and 6-month intervals, wound-bursting pressures were determined in 15 animals from each group. At 1 month and at 6 months, there was no significant difference in wound-bursting strength among the three types of sutures. At 2 months, wounds closed with Teflon-coated braided Dacron were significantly stronger than wounds closed with the other types of sutures. In most of the braided Dacron suture animals, the fascia burst in areas other than the abdominal wound, indicating that the wound was stronger at that time than was the surrounding fascia. There is no advantage to that added strength, and braided Dacron sutures have been shown to cause greater tissue reaction than monofilament sutures. Therefore, except in patients with poor wound healing who are highly susceptible to dehiscence and in whom permanent low-tissue-reaction sutures may be beneficial, the authors recommend a running suture technique using absorbable monofilament suture, such as polydioxanone, for the routine closure of clean abdominal wounds.

The need for ventricular venting with hypothermic cardioplegic arrest is controversial. We report an evaluation of the need for left ventricular venting in a canine model that closely simulates conditions during routine coronary artery bypass grafting (CABG). Thirty-five dogs were placed on cardiopulmonary bypass for 60 minutes of hypothermic cardioplegic arrest (18 vented, 17 nonvented) and then reperfused for 30 minutes. Myocardial temperature and left atrial pressure (LAP) were recorded continuously. Before and 30 minutes after hypothermic cardioplegic arrest, left ventricular function curves were generated (six vented, six nonvented), and biopsy specimens of the left ventricle were taken for adenosine triphosphate (ATP) determinations (11 vented, 10 nonvented) and semiquantitative grading of mitochondrial ultrastructure (six vented, six nonvented). LAP in nonvented dogs was 7.4 mm Hg during hypothermic cardioplegic arrest and 5.0 mm Hg during reperfusion. Temperature during hypothermic cardioplegic arrest was 12.3 degrees C in vented dogs and 11.3 degrees C in nonvented dogs (p = 0.5). There were no differences in left ventricular function or preservation of mitochondrial ultrastructure between vented and nonvented dogs. ATP after hypothermic cardioplegic arrest was 96.6% of control (4.30 microM/gm) in vented dogs and 94.6% (4.37 microM/gm) in nonvented dogs (p = 0.7). The absence of left ventricular venting did not lead to ventricular distention or more rapid rewarming. These data in vented dogs and nonvented dogs strongly support the belief that left ventricular venting is not necessary during routine CABG.

Hematuria after blunt abdominal trauma is common with multiple organ system injuries, and many trauma centers routinely perform intravenous pyelography (IVP) on all trauma patients having any degree of hematuria. However, it has been suggested that many IVPs could be avoided if more selective criteria were used. To help determine the need for an IVP, we reviewed the records of 102 consecutive patients undergoing IVP after blunt abdominal trauma over a 17-month period. Twenty-six (25%) patients had gross hematuria. Of these, seven (27%) had abnormal IVPs, and two (7.7%) of those required urologic surgery. Seventy-six (75%) patients had microscopic hematuria. Of these, one (1.3%) had an abnormal IVP but required no urologic surgery. Thus, if IVP had been performed only when gross hematuria was present, then all surgically significant urinary tract lesions would have been recognized, and 75 per cent of these 102 patients would have been spared IVPs. We agree with others that microscopic hematuria alone is not an indication for emergency IVP in these trauma patients. However, gross hematuria or other strong clinical evidence of renal injury still mandates IVP early during the assessment of patients who have suffered blunt abdominal trauma.

An inexpensive femoral "cuff" developed in this noninvasive vascular laboratory allows pulse volume recordings and systolic pressure measurements of the femoral arteries. Using the parameters 1) femoral/brachial systolic pressure ratio, 2) wave amplitude, and 3) status of the dicrotic notch for assessment of results, it was found that the cuff correctly identified 59 of 62 limbs with at least 50% aortoiliac stenosis, with only two false-positive results, for an accuracy of 97%. The high, wide thigh cuff identified 57 of the 62 limbs, but had 45 false-positive results (77% accuracy). Use of the femoral "cuff" has refined the ability to identify the anatomic location of significant arterial stenoses in the lower extremities.

Polytetrafluoroethylene (PTFE) grafts, 1 mm in internal diameter, were interpositioned in the infrarenal aortas of 20 adult Sprague-Dawley rats with either continuous or interrupted sutures. The interrupted-suture (I-S) technique was used in ten rats, the continuous-suture (C-S) technique in the other ten. After followup of 90 days, the overall patency rate for the 20 rats was 95% (19/20); all grafts in the C-S group were patent; one graft in the I-S group had occluded on the day of operation. Since excellent patency rates were obtainable with these minute PTFE grafts placed in the rat aorta by either technique, the speed with which the C-S technique can be accomplished appears to make it preferable.