Computer clinical decision support that automates personalized clinical care: a challenging but needed healthcare delivery strategy

How to deliver best care in various clinical settings remains a vexing problem. All pertinent healthcare-related questions have not, cannot, and will not be addressable with costly time- and resource-consuming controlled clinical trials. At present, evidence-based guidelines can address only a small fraction of the types of care that clinicians deliver. Furthermore, underserved areas rarely can access state-of-the-art evidence-based guidelines in real-time, and often lack the wherewithal to implement advanced guidelines. Care providers in such settings frequently do not have sufficient training to undertake advanced guideline implementation. Nevertheless, in advanced modern healthcare delivery environments, use of eActions (validated clinical decision support systems) could help overcome the cognitive limitations of overburdened clinicians. Widespread use of eActions will require surmounting current healthcare technical and cultural barriers and installing clinical evidence/data curation systems. The authors expect that increased numbers of evidence-based guidelines will result from future comparative effectiveness clinical research carried out during routine healthcare delivery within learning healthcare systems.

2017 update of the WSES guidelines for emergency repair of complicated abdominal wall hernias

Emergency repair of complicated abdominal wall hernias may be associated with worsen outcome and a significant rate of postoperative complications. There is no consensus on management of complicated abdominal hernias. The main matter of debate is about the use of mesh in case of intestinal resection and the type of mesh to be used. Wound infection is the most common complication encountered and represents an immense burden especially in the presence of a mesh. The recurrence rate is an important topic that influences the final outcome. A World Society of Emergency Surgery (WSES) Consensus Conference was held in Bergamo in July 2013 with the aim to define recommendations for emergency repair of abdominal wall hernias in adults. This document represents the executive summary of the consensus conference approved by a WSES expert panel. In 2016, the guidelines have been revised and updated according to the most recent available literature.

WSES guidelines for management of Clostridium difficile infection in surgical patients

In the last two decades there have been dramatic changes in the epidemiology of Clostridium difficile infection (CDI), with increases in incidence and severity of disease in many countries worldwide. The incidence of CDI has also increased in surgical patients. Optimization of management of C difficile, has therefore become increasingly urgent. An international multidisciplinary panel of experts prepared evidenced-based World Society of Emergency Surgery (WSES) guidelines for management of CDI in surgical patients.

Differential induction of PPAR-gamma by luminal glutamine and iNOS by luminal arginine in the rodent postischemic small bowel

Using a rodent model of gut ischemia-reperfusion (I/R), we have previously shown that the induction of inducible nitric oxide synthase (iNOS) is harmful, whereas the induction of heme oxygenase 1 (HO-1) and peroxisome proliferator-activated receptor-gamma (PPAR-gamma) is protective. In the present study, we hypothesized that the luminal nutrients arginine and glutamine differentially modulate these molecular events in the postischemic gut. Jejunal sacs were created in rats at laparotomy, filled with either 60 mM glutamine, arginine, or magnesium sulfate (osmotic control) followed by 60 min of superior mesenteric artery occlusion and 6 h of reperfusion, and compared with shams. The jejunum was harvested for histology or myeloperoxidase (MPO) activity (inflammation). Heat shock proteins and iNOS were quantitated by Western blot analysis and PPAR-gamma by DNA binding activity. In some experiments, rats were pretreated with the PPAR-gamma inhibitor G9662 or with the iNOS inhibitor N-[3(aminomethyl)benzyl]acetamidine (1400W). iNOS was significantly increased by arginine but not by glutamine following gut I/R and was associated with increased MPO activity and mucosal injury. On the other hand, PPAR-gamma was significantly increased by glutamine but decreased by arginine, whereas heat shock proteins were similarly increased in all experimental groups. The PPAR-gamma inhibitor G9662 abrogated the protective effects of glutamine, whereas the iNOS inhibitor 1400W attenuated the injurious effects of arginine. We concluded that luminal arginine and glutamine differentially modulate the molecular events that regulate injurious I/R-mediated gut inflammation and injury. The induction of PPAR-gamma by luminal glutamine is a novel protective mechanism, whereas luminal arginine appears harmful to the postischemic gut due to enhanced expression of iNOS.

Mortality from Isolated Civilian Penetrating Extremity Injury

BACKGROUND

Although studies have ascertained that ten percent of soldiers killed in battle bleed to death from extremity wounds, little data exists on exsanguination and mortality from extremity injuries in civilian trauma. This study examined the treatment course and outcomes of civilian patients who appear to have exsanguinated from isolated penetrating extremity injuries.

METHODS

Five and 1/2 years' data (Aug 1994 to Dec 1999) were reviewed from two Level I trauma centers that receive 95% of trauma patients in metropolitan Houston, TX. Records (hospital trauma registries, emergency medical system (EMS) and medical examiner data) were reviewed on all patients with isolated extremity injuries who arrived dead at the trauma center or underwent cardiopulmonary resuscitation (CPR) or emergency center thoracotomy (ECT).

RESULTS

Fourteen patients meeting inclusion criteria were identified from over 75,000 trauma emergency center (EC) visits. Average age was 31 years and 93% were males. Gunshot wounds accounted for 50% of the injuries. The exsanguinating wound was in the lower extremity in 10/14 (71%) patients and proximal to the elbow or knee in 12/14 (86%). Ten (71%) had both a major artery and vein injured; one had only a venous injury. Prehospital hemorrhage control was primarily by gauze dressings. Twelve (86%) had "signs of life" in the field, but none had a discernable blood pressure or pulse upon arrival at the EC. Prehospital intravenous access was not obtained in 10 patients (71%). Nine patients underwent ECT, and nine were initially resuscitated (eight with ECT and one with CPR). Those undergoing operative repair received an average of 26 +/- 14 units of packed red blood cells. All patients died, 93% succumbing within 12 hours.

CONCLUSION

Although rare, death from isolated extremity injuries does occur in the civilian population. The majority of injuries that lead to immediate death are proximal injuries of the lower extremities. The cause of death in this series appears to have been exsanguination, although definitive etiology cannot be discerned. Intravenous access was not obtainable in the majority of patients. Eight patients (57%) had bleeding from a site that anatomically might have been amenable to tourniquet control. Patients presenting to the EC without any detectable blood pressure and who received either CPR or EC thoracotomy all died.

Inhibition of intestinal transit by resuscitation-induced gut edema is reversed by L-NIL

BACKGROUND

Post-resuscitation gut edema and associated gut dysfunction is a common and significant clinical problem that occurs after traumatic injury and shock. We have shown previously that gut edema without ischemia/reperfusion injury delays intestinal transit [1]. We hypothesized that gut edema increases expression of inducible nitric oxide synthase (iNOS) protein, and that selective iNOS inhibition using L-NIL reverses the delayed intestinal transit associated with gut edema.

MATERIALS AND METHODS

One hour prior to laparotomy, rats were pretreated with 10 mg/kg body weight of intraperitoneal L-NIL or saline vehicle and underwent 80 ml/kg body weight of 0.9% saline + superior mesenteric venous pressure elevation (Edema) or sham surgery (Sham). A duodenal catheter was placed to allow injection of a fluorescent dye for the measurement of intestinal transit. At 6 h, the small bowel was divided and the mean geometric center (MGC) of fluorescent dye was measured to determine transit. Ileum was harvested for histological assessment of mucosal injury, evaluation of iNOS protein expression by Western blotting, and MPO activity. Tissue water was determined using the wet-to-dry weight ratio to assess gut edema. Data are expressed as mean +/- SEM, n = 3-6 and * = P <0.05 using ANOVA.

RESULTS

Gut edema, expressed as increased wet-to-dry ratio, was associated with decreased intestinal transit and elevated iNOS protein expression. Pretreatment with l-NIL improved intestinal transit and decreased expression of iNOS protein without decreasing intestinal tissue water compared to edema animals. There was no difference in mucosal injury or MPO activity among groups.

CONCLUSION

Gut edema delays intestinal transit via an iNOS-mediated mechanism.

Heme oxygenase-1 induction by hemin protects against gut ischemia/reperfusion injury

BACKGROUND

We have shown that both intraischemic hypothermia and hypertonic saline resuscitation provide dramatic protection against gut ischemia/reperfusion (I/R) injury that is in part mediated by heme oxygenase-1 (HO-1). We therefore hypothesized that induction of HO-1 by hemin would lessen damage and improve function after gut I/R.

MATERIALS AND METHODS

Male Sprague-Dawley rats were treated with 50 micromol/kg hemin (HO-1 inducer ferric protoporphyrin IX chloride) sq or vehicle 2 h before superior mesenteric artery occlusion for 60 min or sham laparotomy. After 6 h of reperfusion, transit was determined by quantitation of percentage of tracer in 10 equal segments of small intestine 30 min following injection into the duodenum (expressed as mean geometric center). Ileum was harvested for assessment of mucosal histologic injury (Chiu score 0-5 by blinded observer), myeloperoxidase activity (MPO, index of inflammation), and HO-1 protein expression.

RESULTS

Hemin treatment was associated with increased HO-1 protein expression, lessened mucosal injury, decreased MPO activity, and improved intestinal transit following gut I/R.

CONCLUSION

These data corroborate that HO-1 plays an important role in protecting the gut against I/R-induced injury.

Migrating motility complexes persist after severe traumatic shock in patients who tolerate enteral nutrition

BACKGROUND

Postinjury small bowel ileus is poorly characterized and may be an important factor in intolerance to enteral nutrition (EN). We, therefore, placed jejunal manometry catheters in high-risk trauma patients. Our hypothesis was that the presence of "fasting migrating motility complex (MMC)" activity and conversion to a "fed pattern" at goal rate of EN would be present in those patients who tolerate jejunal feeding.

METHODS

After obtaining baseline fasting manometry pressure tracings, jejunal feeding was advanced stepwise to a set goal while tolerance was monitored and intolerance was treated by a standard approach.

RESULTS

Of the 10 study patients, 7 were able to be maintained on EN. Five (50%) had "fasting MMCs" and had good tolerance to early advancement of EN. The remaining five patients did not exhibit "fasting MMCs" and four had poor tolerance to early advancement of EN. Overall, nine patients reached goal rate of EN of which four converted to a "fed pattern." This, however, was not associated with later tolerance to EN.

CONCLUSION

EN is feasible following severe traumatic shock. Surprisingly, half of the patients had fasting MMCs. This requires intact neural and motor function and was associated with good tolerance of early EN.

Vacuum-assisted wound closure provides early fascial reapproximation in trauma patients with open abdomens

BACKGROUND

Damage control and decompressive laparotomies salvage severely injured patients who would have previously died. Unfortunately, many of these patients develop open abdomens. A variety of management strategies exist. The end result in many cases, however, is a large ventral hernia that requires a complex repair 6 to 12 months after discharge. We instituted vacuum-assisted wound closure (VAWC) to achieve early fascial closure and eliminate the need for delayed procedures.

METHODS

For 12 months ending June 2000, 14 of 698 trauma intensive care unit admissions developed open abdomens and were managed with VAWC dressing. This was changed every 48 hours in the operating room with serial fascial approximation until complete closure.

RESULTS

Fascial closure was achieved in 13 patients (92%) in 9.9 +/- 1.9 days, and 2.8 +/- 0.6 VAWC dressing changes were performed. There were 2 wound infections, no eviscerations, and no enteric fistulas.

CONCLUSIONS

Use of VAWC can safely achieve early fascial closure in more than 90% of trauma patients with open abdomens.

Ischemia/reperfusion-induced disruption of rat small intestine transit is reversed by total enteral nutrition

OBJECTIVES

A reduced blood flow to the gut is a consistent event after traumatic shock. Enteral nutrition support has been shown to reduce the septic morbidity after major trauma. We evaluated the effects of a transient ischemia followed by reperfusion (I/R) and an enteral nutrition support regimen on the motility of the small intestine of the rat.

METHODS

A catheter was placed in the upper duodenum and the small intestine was then made ischemic by clamping the superior mesenteric artery for 45 min; the arteries of sham rats were isolated but not clamped. Intestinal transit was evaluated by measuring the amount of fluorescein isothiocyanate-dextran (12 000 MW) in each of 10 intestinal sections at 30 min after injection through the duodenal catheter. The mean geometric center of marker distribution (MGC) was calculated for each group and compared. In a second study, I/R was followed by infusion of saline or a complete nutrient solution overnight, and transit was determined.

RESULTS

Intestinal transit (as the MGC) of I/R rats at 24 h after the beginning of reperfusion (3.5 +/- 0.2) and 48 h after the beginning of reperfusion (4.5 +/- 1.1) was significantly lower than that in the respective sham controls (5.1 +/- 0.3 and 5.9 +/- 0.5). The MGC for rats receiving a nutrient solution overnight during the reperfusion phase (6.0 +/- 1.1) was significantly increased compared with the MGC of 4.8 +/- 0.3 for rats receiving saline during the same period.

CONCLUSIONS

These results demonstrate a long-term deleterious effect of a non-lethal ischemia on intestinal transit and may be one explanation for many of the sequelae occurring after ischemia. In addition, these results demonstrate that a nutrient infusion will prevent the delayed transit. This may provide a partial explanation for the beneficial effects of total enteral nutrition in the clinical situation of posttraumatic injury.

[Enteral feeding of glucose increases intestinal mucosal blood flow during intestinal ischemia/reperfusion injury]

OBJECTIVE

To explore the relationship between enteral nutrition and the change in intestinal mucosal blood flow during intestinal ischemia/reperfusion injury.

METHODS

Thirty-six Sprague-Dawley rats were randomly divided into alanine (12 rats), glucose (14 rats) and mannitol control (10 rats) groups. Jejunal sac was prepared with the filling of either 10 mM alanine, glucose or mannitol in the three groups. The laser doppler probe and intestinal mucosal tonometry were placed at the both ends of the sac. The superior mesenteric artery was occluded by arterial clamp for 60 mins and released thereafter for another 60 mins. Intestinal mucosal blood flow and regional pressure of CO(2) (PrCO(2)) were determined every 30 mins.

RESULTS

During the process of ischemia/reperfusion, the intestinal mucosal blood flow in glucose group increased evidently and the PrCO(2) in glucose group decreased obviously (P < 0.01) when comparcd with those in mannitol group.

CONCLUSION

During the process of ischemia/reperfusion, enteral feeding of glucose could increase intestinal mucosal blood flow, which provided guarding effects on the intestine suffering from ischemic/reperfusion injury.

Inducible nitric oxide synthase mediates gut ischemia/reperfusion-induced ileus only after severe insults

Inducible nitric oxide synthase (NOS 2) is thought to play a role in gut motility disorders that occur under proinflammatory conditions. Clinically, ileus occurs after sepsis and shock-induced gut ischemia/reperfusion (I/R). The purpose of this study was to determine if NOS 2 mediates impaired intestinal transit in well-established models of both moderate and severe gut ischemia/reperfusion. At laparotomy, Sprague-Dawley rats had duodenal catheters placed. Small intestinal transit was determined by quantitating the percentage tracer (FITC-dextran) in 10 equal segments of intestine 30 min after catheter injection [expressed as the mean geometric center (MGC) of distribution]. Transit was assessed at 6 and 24 h after gut ischemia [45 or 75 min of superior mesenteric artery occlusion (SMAO) with sham laparotomy as control]. In a separate set of experiments, N(6)-(iminoethyl)-L-lysine (L-NIL), a selective NOS 2 antagonist, was administered 1 h prior to laparotomy and transit was determined after 6 h as described above. Ileal NOS 2 expression was assessed by Western immunoblot and quantitative "real-time" RT-PCR. We observed that both 45 and 75 min of SMAO decreased intestinal transit at 6 h of reperfusion compared to sham. Ileal NOS 2 mRNA and protein were increased after 75, but not 45, min of SMAO. In addition, L-NIL improved transit after 75, but not 45, min of SMAO. We conclude that (1) NOS 2 is upregulated in the gut only after more severe ischemic insults, and (2) ileus is mediated, at least in part, by NOS 2 under these conditions.

Computerized decision support for mechanical ventilation of trauma induced ARDS: results of a randomized clinical trial

BACKGROUND

Variability and logistic complexity of mechanical ventilatory support of acute respiratory distress syndrome, and need to standardize care among all clinicians and patients, led University of Utah/LDS Hospital physicians, nurses, and engineers to develop a comprehensive computerized protocol. This bedside decision support system was the basis of a multicenter clinical trial (1993-1998) that showed ability to export a computerized protocol to other sites and improved efficacy with computer- versus physician-directed ventilatory support. The Memorial Hermann Hospital Shock Trauma intensive care unit (ICU) (Houston, TX; a Level I trauma center and teaching affiliate of The University of Texas Houston Medical School) served as one of the 10 trial sites and recruited two thirds of the trauma patients. Results from the trauma patient subgroup at this site are reported to answer three questions: Can a computerized protocol be successfully exported to a trauma ICU? Was ventilator management different between study groups? Was patient outcome affected?

METHODS

Sixty-seven trauma patients were randomized at the Memorial Hermann Shock Trauma ICU site. "Protocol" assigned patients had ventilatory support directed by the bedside respiratory therapist using the computerized protocol. "Nonprotocol" patients were managed by physician orders.

RESULTS

Of the 67 trauma patients randomized, 33 were protocol (age 40 +/- 3; Injury Severity Score [ISS] 26 +/- 3; 73% blunt) and 34 were nonprotocol (age 38 +/- 2; ISS 25 +/- 2; 76% blunt). For the protocol group, the computerized protocol was used 96% of the time of ventilatory support and 95% of computer-generated instructions were followed by the bedside respiratory therapist. Outcome measures (i.e., survival, ICU length of stay, morbidity, and barotrauma) were not significantly different between groups. Fio2 > or = 0.6 and Pplateau > or = 35 cm H2O exposures were less for the protocol group.

CONCLUSION

A computerized protocol for bedside decision support was successfully exported to a trauma center, and effectively standardized mechanical ventilatory support of trauma-induced acute respiratory distress syndrome without adverse effect on patient outcome.

Post-injury multiple organ failure: the role of the gut

Despite intensive investigation, the pathogenesis of post-injury multiple organ failure (MOF) remains elusive. Laboratory and clinical research strongly suggests that the gastrointestinal tract (i.e., the gut) plays a pivotal pathogenic role. Since its inception in 1988, the Trauma Research Center (TRC) at the University of Texas-Houston Medical School (UTHMS) has focused its efforts on elucidating the role of the gut in post-injury MOF. On the basis of our observations and those of others, we believe that 1) shock with resulting gut hypoperfusion is an important inciting event, 2) the reperfused gut is a source of proinflammatory mediators that can amplify the early systemic inflammatory response syndrome (SIRS) and thus contribute to early MOF, 3) early gut hypoperfusion causes an ileus in both the stomach and small bowel that sets the stage for progressive gut dysfunction so that the proximal gut becomes a reservoir for pathogens and toxins that contribute to late sepsis-associated MOF, and 4) late infections cause further worsening of this gut dysfunction. Thus, the gut can be both an instigator and a victim of MOF. The purpose of this article is to provide the rationale behind these beliefs and to provide a brief overview of the ongoing research projects in the TRC at UTHMS.

Nitroprusside in resuscitation of major torso trauma

OBJECTIVE

Patients with thoracic aortic injury (TAI) usually have sustained other major trauma, and may require aggressive shock resuscitation. In the 24 hours after aortic repair and during resuscitation, our cardiothoracic surgeons request intravenous nitroprusside to maintain mean arterial pressure (MAP) less than 90 mm Hg to minimize bleeding at the repair. We compared the resuscitation response of patients who sustained major torso trauma (MTT) and TAI with that of patients who had MTT with no TAI to determine whether nitroprusside can effectively control MAP during resuscitation and whether use of nitroprusside, because of its peripheral vasodilatory effects, is associated with a favorable resuscitation response.

METHODS

During the 9-month study period, 11 patients who sustained TAI and 38 patients who sustained MTT with no TAI met multiple organ failure risk/shock criteria and were resuscitated by a standardized protocol emphasizing volume loading and hemoglobin replacement to maintain systemic oxygen delivery index (DO2I) > or = 600 mL O2/min-m2 for the first 24 intensive care unit hours. For TAI patients, postoperative management included intravenous nitroprusside infusion titrated by the bedside nurse to maintain mean arterial pressure (MAP) less than 90 mm Hg during the same 24 hours. Data were obtained prospectively during resuscitation. Retrospectively, the resuscitation response of TAI and non-TAI patients was compared.

RESULTS

For the TAI group, nitroprusside effectively controlled MAP (range, 77-87 mm Hg); for the non-TAI group, mean MAP exceeded 95 mm Hg within 5 hours. During the first 8 hours, MAP, pulmonary capillary wedge pressure, and systemic vascular resistance index were less, and DO2I was greater for the TAI than for the non-TAI group. The resuscitation goal of DO2I > or = 600 mL O2/ min-m2 was attained at 4 hours for the TAI group, and was attained at 12 hours for the non-TAI group. No revisions of aortic repairs were required during or as a result of resuscitation.

CONCLUSION

During aggressive shock resuscitation, control of MAP using nitroprusside is feasible and is associated with a favorable resuscitation response. Nitroprusside may be a useful adjunct during shock resuscitation of MTT as a vasoactive agent that promotes peripheral tissue perfusion.

Blunt trauma resuscitation: the old can respond

HYPOTHESIS

Old and young trauma patients are capable of hyperdynamic response during standardized shock resuscitation.

DESIGN

The responses of old and young trauma patients resuscitated using a standardized protocol are compared in an inception cohort study. A standardized resuscitation protocol was used to attain and maintain an oxygen delivery index of 600 mL/min x m2 or greater (DO2I > or = 600) for the first 24 hours in the intensive care unit. Interventions, responses, and outcomes for old (> or = 65 years) and young (<65 years) patients are described. Data were analyzed using analysis of variance, the chi2 test, and the t test; P<.05 was considered significant.

SETTING

A 20-bed shock trauma intensive care unit in a regional level I trauma center.

PATIENTS

Patients at high risk of postinjury multiple organ failure, ie, major organ or vascular injury and/or skeletal fractures, initial base deficit of 6 mEq/L or greater, need for 6 units or more of packed red blood cells in the first 12 hours, or age of 65 years or older with any 2 previous criteria.

INTERVENTIONS

Pulmonary artery catheter, crystalloid fluid infusion, packed red blood cell transfusion, and moderate inotrope support, as needed in that sequence, to attain DO2I > or = 600.

MAIN OUTCOME MEASURES

Intensive care unit length of stay and survival.

RESULTS

During 19 months ending June 1999, 12 old patients (58% male; age, 76 +/- 2 years [mean +/- SEM] [P<.0011; Injury Severity Score, 20 +/- 2 [P=.02]) and 54 young patients (61% male; age, 37 +/- 2 years; Injury Severity Score, 32 +/- 2) were resuscitated. Initially, for old patients (cardiac index, 2.0 +/- 0.2 L/min x m2) and for young patients (cardiac index, 3.0 +/- 0.2 L/min x m2; P=.01), 24-hour volumes were as follows: 16 +/- 3 L of crystalloid and 12 +/- 3 units of packed red blood cells for the old patients and 21 +/- 2 L of crystalloid and 19 +/- 2 units of packed red blood cells for the young patients. For old patients, 9 (75%) attained DO2I > or = 600, and 11 (92%) survived 7 or more days and 5 (42%) 30 or more days. For young patients, 45 (83%) attained the DO2I goal, and 48 (89%) survived 30 or more days. Intensive care unit length of stay was 25 +/- 9 days for the old patients and 23 +/- 2 days for the young patients.

CONCLUSIONS

Elderly patients have initially depressed cardiac index but generate hyperdynamic response. Although ultimate outcome is poorer than in the younger cohort, resuscitation is not futile.

Age should not be a consideration for nonoperative management of blunt splenic injury

BACKGROUND

Operative management of blunt splenic injury is recommended for adults > or = 55 years. Because this is not our practice, we did a retrospective review to compare outcomes of patients > or = 55 years old versus patients < 55 years old.

METHODS

During a 5-year period ending in July of 1998, 461 patients (3%) admitted to our Level I trauma center had a blunt splenic injury. Eighty-six patients (19%) died within 24 hours of massive injuries, leaving 375 patients for evaluation. Data were obtained from our trauma registry and medical records.

RESULTS

A total of 29 patients (8%) were > or = 55 years old (mean age, 67 +/- 2 years; mean injury severity score [ISS] 25 +/- 2). Of these, 18 patients (62%) underwent nonoperative management (NOM). A total of 346 patients (92%) were < 55 years old (mean age, 28 +/- 0.6; mean ISS, 20 +/- 1). Of these, 198 patients (57%) underwent NOM. The failure rate was not different between the two age groups (17% vs. 14%). However, the ISS and mortality rate were significantly higher in the older age group that failed (ISS, 29.3 +/- 2.6 vs. 19.5 +/- 2.1; mortality: 67% vs. 4%). None of the deaths could be attributed to splenic injury.

CONCLUSION

Adults > or = 55 years old with blunt splenic injury are successfully treated by NOM. Although older adults had significantly greater injuries, they had similar failure rates of NOM when compared with younger adults. Older adults had significantly higher mortality, but this was not a result of their splenic injury. Therefore, age should not be a criteria for NOM of blunt splenic injury.

Tissue hemoglobin O2 saturation during resuscitation of traumatic shock monitored using near infrared spectrometry

BACKGROUND

Near infrared (NIR) spectrometry offers a noninvasive monitor of tissue hemoglobin O2 saturation and has been developed to report a quantitative clinical variable, StO2 [= HbO2/(HbO2 + Hb)]. In this study, a prototype NIR oximeter was used to investigate the hypothesis that changes in systemic O2 delivery index (D(O2)I) would be reflected by changes in StO2 in skeletal muscle, subcutaneous tissue, or both, as reperfusion occurs during shock resuscitation. StO2 was also compared with other indices of severity of shock or adequacy of resuscitation, including arterial base deficit, lactate, gastric mucosal P(CO2) (PgCO2), and mixed venous hemoglobin O2 saturation (S(VO2)).

METHODS

Skeletal muscle and subcutaneous tissue StO2 were monitored simultaneously in eight severely injured trauma patients (88% blunt mechanism; age, 42 +/- 6 years; Injury Severity Score, 27 +/- 3) during standardized shock resuscitation in the intensive care unit with the primary goal of D(O2)I > or = 600 mL O2/min/m2 for 24 hours, and for an additional 12 hours during transition from resuscitation to standard intensive care unit care.

RESULTS

Skeletal muscle StO2 increased significantly from 15 +/- 2% (mean +/- SEM) at the start of resuscitation to 49 +/- 14% at 24 hours, and to approximately 55% from 25 to 36 hours. Subcutaneous tissue StO2 approximately 82% and was significantly greater than skeletal muscle StO2 throughout. D(O2)I increased significantly from 372 +/- 54 to 718 +/- 47 mL O2/min/m2 during resuscitation. Over 36 hours, mean D(O2)I and skeletal muscle StO2 were highly correlated (r = 0.95). Neither D(O2)I-PgCO2 nor D(O2)I-S(VO2) were significantly correlated; neither S(VO2) nor subcutaneous tissue StO2 changed significantly.

CONCLUSION

Hemoglobin O2 saturation was monitored noninvasively and simultaneously in skeletal muscle and subcutaneous tissues as StO2 (%) by using a prototype NIR oximeter. Skeletal muscle StO2 tracked systemic O2 delivery during and after resuscitation. As a rapidly deployable, noninvasive monitor of peripheral tissue oxygenation and O2 delivery, skeletal muscle StO2 obtained using NIR spectrometry would be useful to guide resuscitation in the intensive care unit, to monitor resuscitation status in the operating room, and, potentially, in combination with indicators such as base deficit and lactate, to detect shock during initial assessment of the severe trauma patient in the emergency department.

Nonocclusive bowel necrosis occurring in critically ill trauma patients receiving enteral nutrition manifests no reliable clinical signs for early detection

BACKGROUND

Nonocclusive bowel necrosis (NOBN) has been associated with early enteral nutrition (EN). The purpose of this study was to determine the incidence of this complication in our trauma intensive care unit population and to define a typical patient profile vulnerable to NOBN.

METHODS

Thirteen cases of NOBN were identified among 4,311 patients (0.3%) over a 64-month period ending October 1998. Their charts were analyzed for a variety of clinical data, including prospective EN tolerance data in 4.

RESULTS

Twelve (92%) patients were enterally fed prior to diagnosis for 10 +/- 8 days (range 3 to 21). Tachycardia (n = 12, 92%); fever/hypothermia, (n = 12, 92%), and an abnormal white blood cell count (n = 11, 85%) were consistently present. Abdominal distention was common but tended to be a late sign (n = 12). Seven (56%) survived. In 4 patients with tolerance data, 3 reached the goal rate of feeds prior to diagnosis. Two became distended at >12 hours from diagnosis. Gastric tonometry demonstrated a decreased NgpHi (<7.30) after starting EN in all 3 in whom it was monitored.

CONCLUSIONS

NOBN developed in 0.3% of our trauma patients. Onset occurs in the second week in high-acuity patients who have had a period of EN tolerance. Clinical findings resemble bacterial sepsis with tachycardia, fever, and leukocytosis. Gastrointestinal specific signs are not consistent or occur late. Thus, we could not identify an early, useful clinical indicator. Gastric carbon dioxide tonometry may detect a vulnerable subgroup of patients.

The role of the gastrointestinal tract in postinjury multiple organ failure

Despite intensive investigation, the pathogenesis of postinjury multiple organ failure (MOF) remains elusive. Laboratory and clinical research strongly implicate that the gastrointestinal tract plays a pivotal role. Shock with resulting gut hypoperfusion appears to be one important inciting event. While early studies persuasively focused attention on bacterial translocation as a unifying mechanism to explain early and late sepsis syndromes that characterize postinjury MOF, subsequent studies suggest that other gut-specific mechanisms are operational. Based on our Trauma Research Center observations and those of others, we conclude that: 1) bacterial translocation may contribute to early refractory shock; 2) for patients who survive shock, the reperfused gut appears to be a source of proinflammatory mediators that may amplify the early systemic inflammatory response syndrome; and 3) early gut hypoperfusion sets the stage for progressive gut dysfunction such that the gut becomes a reservoir for pathogens and toxins that contribute to late MOF.

Release of anti-inflammatory mediators after major torso trauma correlates with the development of postinjury multiple organ failure

BACKGROUND

Soluble tumor necrosis factor receptor (sTNFr) and interleukin-1 receptor antagonist (IL-1ra) have been identified as endogenous inhibitors of TNF-alpha and IL-1beta. While TNF-alpha and IL-1beta levels are not systematically elevated in postinjury patients who developed multiorgan failure (MOF), their involvement at the tissue level has been suggested. Our study hypothesis was that levels of sTNFr-I and IL-1ra would discriminate patients at risk for postinjury MOF.

METHODS

Serial plasma levels of sTNFr and IL-1ra were measured in 29 trauma patients at high risk for postinjury MOF.

RESULTS

sTNFr-I levels were higher in MOF compared with non-MOF patients at 12, 84, and 132 hours postinjury. MOF patients also had higher IL-1ra values 36, 60, 84, and 132 hours postinjury.

CONCLUSIONS

Anti-inflammatory mechanisms are activated after trauma. Since increased levels of sTNFr and IL-1ra correlate with postinjury MOF, they may contribute to our understanding of the pathogenesis as well as prediction of outcome. High levels of antagonists to TNF-alpha and IL-1beta suggest tissue level involvement of these cytokines in postinjury hyperinflammation.

Blunt versus penetrating subclavian artery injury: presentation, injury pattern, and outcome

BACKGROUND

Subclavian artery (SCA) injuries are rare vascular injuries and may be difficult to manage. The majority of SCA injuries are secondary to penetrating trauma. The purpose of this report is to examine the injury patterns, diagnostic and therapeutic approaches, and outcome of patients with blunt and penetrating SCA injuries.

METHODS

Retrospective review

RESULTS

Fifty-six patients sustained SCA injuries (25 blunt, 31 penetrating). SCA injury location was evenly distributed between the proximal, middle, and distal SCA after penetrating trauma; proximal injuries were rare (2 of 25) with blunt mechanisms. A radial arterial pulse deficit was present in only 3 of 25 blunt injuries and 9 of 31 penetrating injuries. Complications occurred more commonly in both groups of patients with initial systolic blood pressures less than 90 mm Hg. Survival was 76% in blunt and 81% in penetrating groups; limb salvage was similar (92% in blunt and 97% in penetrating groups). Complete brachial plexus injuries were more common with blunt injuries.

CONCLUSION

SCA injuries are rare vascular injuries with an associated high morbidity and mortality, regardless of mechanism. Blunt mechanisms result in more middle and distal injuries and more frequent complete brachial plexus injuries. Complications are related to the hemodynamic status of the patient upon presentation, and not to mechanism of injury.

Delayed diagnosis of blunt duodenal injury: an avoidable complication

BACKGROUND

There is controversy about the impact on morbidity from delayed diagnoses of blunt hollow viscus injuries. A recent study suggested that the increased morbidity was primarily from delayed diagnosis of blunt duodenal injury (BDI).

STUDY DESIGN

We studied the medical records from a 10-year period from June 1987 to June 1997 examining the data on 22,163 cases of blunt trauma. We assessed the incidence and consequences of delayed diagnoses of BDI, and identified preoperative factors associated with these delayed diagnoses.

RESULTS

Thirty-five patients (0.2%) were identified in the retrospective study of the records from 22,163 blunt trauma patients to have sustained BDI. Of these, 25 patients (71%) were male. Ages ranged from 1 to 58 years (mean 18.8 years), and the predominant mechanism was motor vehicle accident in 18 patients (51%). Seven patients (20%) (group I) had a diagnostic delay of > 6 hours; 28 patients (80%) (group II) were diagnosed in < 6 hours. Six of the seven group I patients (86%) were evaluated initially with CT scans, and five (83%) showed findings suggestive of BDI. Among the 28 group II patients, 14 (50%) underwent initial diagnostic peritoneal lavage (DPL), and 14 (50%) had a CT scan. In seven of the group II patients (50%) who were initially evaluated by CT scan, there were findings suggestive of BDI. Diagnostic peritoneal lavage was initially equivocal (red blood cell count=5,000 to 100,000) in the remaining one group I patient compared with three of the group II patients who had DPL. Deterioration found on physical examinations prompted followup CT scans in 6 group I patients (86%), and the scans were diagnostic for BDI in all cases.

CONCLUSIONS

Blunt duodenal injury is an uncommon entity. Despite the presence of suggestive CT and DPL findings, the diagnosis was delayed in 20% of the 35 patients whose records were examined in the study; this delayed diagnosis was associated with increased abdominal complications. Patients with persistent abdominal complaints and equivocal CT or DPL findings should undergo laparotomy or repeat CT scan evaluations.

Multiple organ failure can be predicted as early as 12 hours after injury

BACKGROUND

The failure of therapies aimed at modulating systemic inflammatory response syndrome and decreasing multiple organ failure (MOF) has been attributed in part to the inability to identify early the population at risk. Our objective, therefore, was to develop predictive models for MOF at admission and at 12, 24 and 48 hours after injury.

METHODS

Logistic regression models were derived in a data set with 411 adult trauma patients using indicators of tissue injury, shock, host factors, and the Acute Physiology Score-Acute Physiology and Chronic Health Evaluation III (APS-APACHE III).

RESULTS

MOF was diagnosed in 78 patients (19%). Injury Severity Score, platelet count, and age emerged as predictors in all models. Transfused blood, inotropes, and lactate were significant predictors at 12, 24, and 48 hours, but not at admission. The APS-APACHE III emerged only in the 0- to 48-hour model and offered minimal improvement in predictive power. Good predictive power was achieved at 12 hours after injury.

CONCLUSION

Postinjury MOF can be predicted as early as 12 hours after injury. The APS-APACHE III added little to the predictive power of tissue injury, shock and host factors.

Hollow visceral injury and blunt trauma

BACKGROUND

The incidence of hollow viscus injury (HVI) after blunt trauma (BT) is variable, and differences between children and adults have not been well described. The purpose of this study is to determine the age-group-related incidence and characteristics of BT-associated HVI as well as the clinical markers and consequences of delayed diagnosis.

METHODS

A 9-year trauma registry review of all patients with HVI.

RESULTS

A large sample of patients (19,621) with BT were evaluated (2,550 < or = 14 years old; 17,070 > 14 years old). One hundred thirty-nine of 17,070 (0.8%) adults had HVI compared with 27 of 2,550 (1%) children. HVI occurred more frequently in the duodenum in children (11 of 27) compared with adults (17 of 139) (p < 0.05). Among patients with abdominal wall ecchymosis, 13.5% of children had HVI compared with 10.6% of adults. Delays in diagnosis of HVI occurred in 9 of 27 children compared with 10 of 139 adults (p < 0.0 5). Delayed diagnosis was associated with increased abdominal septic complications in both children (4 of 9) and adults (2 of 10) compared with diagnosis at presentation (p < 0.05).

CONCLUSION

HVI occurs with a similar low frequency in both children and adults. Duodenal injuries are more common in pediatric BT patients. Abdominal wall ecchymosis is associated with increased HVI but is less predictive of HVI than previously described. Contrary to previous reports, delays in diagnosis are associated with increased morbidity.

Delayed complications of nonoperative management of blunt adult splenic trauma

OBJECTIVE

To determine the incidence and type of delayed complications from nonoperative management of adult splenic injury.

DESIGN

Retrospective medical record review.

SETTING

University teaching hospital, level I trauma center.

PATIENTS

Two hundred eighty patients were admitted to the adult trauma service with blunt splenic injury during a 4-year period. Men constituted 66% of the population. The mean (+/-SEM) age was 32.2+/-1.0 years and the mean (+/-SEM) Injury Severity Score was 22.8+/-0.9. Fifty-nine patients (21%) died of multiple injuries within 48 hours and were eliminated from the study. One hundred thirty-four patients (48%) were treated operatively within the first 48 hours after injury and 87 patients (31%) were managed nonoperatively.

MAIN OUTCOME MEASURES

We reviewed the number of units of blood transfused, intensive care unit length of stay, overall length of stay, outcome, and complications occurring more than 48 hours after injury directly attributable to the splenic injury.

RESULTS

Patients managed nonoperatively had a significantly lower Injury Severity Score (P<.05) than patients treated operatively. Length of stay was significantly decreased in both the number of intensive care unit days as well as total length of stay (P<.05). The number of units of blood transfused was also significantly decreased in patients managed nonoperatively (P<.05). Seven patients (8%) managed nonoperatively developed delayed complications requiring intervention. Five patients had overt bleeding that occurred at 4 days (3 patients), 6 days (1 patient), and 8 days (1 patient) after injury. Three patients underwent splenectomy, 1 had a splenic artery pseudoaneurysm embolization, and 1 had 2 areas of bleeding embolization. Two patients developed splenic abscesses at approximately 1 month after injury; both were treated by splenectomy.

CONCLUSION

Significant numbers of delayed splenic complications do occur with nonoperative management of splenic injuries and are potentially life-threatening.

Operative treatment of truncal vascular injuries in children and adolescents

BACKGROUND/PURPOSE

Pediatric truncal vascular injuries are rare, but the reported mortality rate is high (35% to 55%), and similar to that in adults (50% to 65%). This report examines the demographics, mechanisms of injury, associated trauma, and results of treatment of pediatric patients with noniatrogenic truncal vascular injuries.

METHODS

A retrospective review (1986 to 1996) of a pediatric (< or = 17 years old) trauma registry database was undertaken. Truncal vascular injuries included thoracic, abdominal, and neck wounds.

RESULTS

Fifty-four truncal vascular injuries (28 abdominal, 15 thoracic, and 11 neck injuries) occurred in 37 patients (mean age, 14+/-3 years; range, 5 to 17 years); injury mechanism was penetrating in 65%. Concomitant injuries occurred with 100% of abdominal vascular injuries and multiple vascular injuries occurred in 47%. Except for aortic and one SMA injury requiring interposition grafts, these wounds were repaired primarily or by lateral venorrhaphy. Nonvascular complications occurred more frequently in patients with abdominal injuries who were hemodynamically unstable (systolic blood pressure [BPS] <90) on presentation (19 major complications in 11 patients versus one major complication in five patients). Thoracic injuries were primarily blunt rupture or penetrating injury to the thoracic aorta (nine patients). Thoracic aortic injuries were treated without bypass, using interposition grafts. In patients with thoracic aortic injuries, there were no instances of paraplegia related to spinal ischemia (clamp times, 24+/-4 min); paraplegia occurred in two patients with direct cord and aortic injuries. Concomitant injuries occurred with 83% of thoracic injuries and multiple vascular injuries occurred in 25%. All patients with thoracic vascular injuries presenting with BPS of less than 90 died (four patients), and all with BPS 90 or over survived (eight patients). There were 11 neck wounds in 9 patients requiring intervention, and 8 were penetrating. Overall survival was 81%; survival from abdominal vascular injuries was 94%, thoracic injuries 66%, and neck injuries 78%.

CONCLUSIONS

Survival and subsequent complications are related primarily to hemodynamic status at the time of presentation, and not to body cavity or vessel injured. Primary anastomosis or repair is applicable to most nonaortic wounds. The mortality rate in pediatric abdominal vascular injuries may be lower than previously reported.

Effects of facial nerve injury on mouse motoneurons lacking the p75 low-affinity neurotrophin receptor

When motoneuron axons in peripheral nerves are injured, the expression of the p75 low-affinity neurotrophin receptor (p75) increases in their cell bodies and axons, as well as in the Schwann cells undergoing Wallerian degeneration in the distal excised nerve segment. To understand the role of p75 in the events following nerve injury, we have examined the survival and regeneration of motoneurons in mice lacking the p75 receptor. In adult p75 (-/-) mice, functional recovery of whiskers movement following a facial nerve crush occurred slightly earlier than in p75 (+/+) mice, and some recovery of function over a 25-day interval following a nerve cut occurred more frequently in p75 (-/-) mice. Motoneuron profile numbers were slightly reduced in p75 (-/-) mice, and there were correspondingly fewer axons in the facial nerve. At 25 days following axotomy, profile survival in the adult p75 (-/-) mice was significantly improved compared to p75 (+/+) mice (mean 85%+/-standard error of the mean 3%, n = 11 vs. 67+/-5%, n = 11 in CD-1 mice and 68.0+/-4%, n = 6 in balb/c mice), and significantly more regenerating axons were present in the distal facial nerve. After axotomy on postnatal day 1, there was almost total loss of motoneuron profiles in the lateral facial nucleus in p75 (+/+) mice (1.7+/-0.3% remained, n = 5), while significantly more survived in p75 (-/-) mice (17 +/-2.5 %, n = 6). We conclude that expression of p75 in motoneurons or Schwann cells following facial nerve injury is not necessary for motoneuron survival or prompt regeneration of their axons; rather, p75 may increase their risk of dying.

Prospective characterization and selective management of the abdominal compartment syndrome

BACKGROUND

The abdominal compartment syndrome (ACS) is now recognized as a frequent confounder of surgical critical care following major trauma; however, few prospective data exist concerning its characterization, evolution, and response to decompression.

METHODS

Acutely injured patients with an injury severity scale (ISS) score >15 requiring emergent laparotomy and intensive care unit (ICU) admission were prospectively evaluated for the development of ACS. The syndrome was defined as an intra-abdominal pressure (IAP) >20 mm Hg complicated by one of the following: peak airway pressure (PAP) >40 cm H2O, oxygen delivery index (DO2I) <600 mL O2/min/m2, or urine output (UO) <0.5 mL/kg/hr. Physiologic response to decompression was similarly documented prospectively.

RESULTS

Over a 14-month period ending December 1995, 21 (14%) of 145 patients (ISS >15) requiring laparotomy and admitted to our surgical ICU developed ACS; mean age was 39 +/- 9 years; injury mechanism was blunt in 60%; ISS 26 +/- 6. At initial laparotomy, 67% underwent abdominal packing (57% for major liver injuries). Mean IAP was 27 +/- 2.3 mm Hg, and time from laparotomy to decompression was 27 +/- 4 hours; 24% were planned whereas the remaining were prompted by deteriorating organ function as defined above (cardiopulmonary in 43%; renal in 19%; both renal and cardiopulmonary in 14%). Following decompression, there was an increase in cardiac index, oxygen delivery, urine output, and static compliance while there was a decrease in pulmonary capillary wedge pressure, systemic vascular resistance, and peak airway pressure.

CONCLUSIONS

The abdominal compartment syndrome occurs in a significant number of severely injured patients, and it develops quickly (27 +/- 4 hours). Cardiopulmonary deterioration is the most frequent reason prompting decompression. Timely decompression of the ACS results in improvements in cardiopulmonary and renal function. These data support the use of the proposed ACS grading system for selective management of the syndrome.

Pulmonary contusion: are children different?

BACKGROUND

Pulmonary contusion (PC) is a common sequelae of blunt trauma in adults and children; previous reports suggest that children have more favorable outcomes because of differences in mechanisms of injury, associated injury, and physiologic response. Our objective was to determine whether children who sustain PC have different outcomes compared with similarly injured adults.

STUDY DESIGN

Our Level I Trauma Registry was reviewed for a 4-year period and identified 251 consecutive patients who sustained PC. Their charts were reviewed retrospectively for demographics, injury mechanism, injury severity scores, associated injuries, and outcomes (measured by the need for intubation, ventilation days, pneumonia, acute respiratory distress syndrome, and death). Data are expressed as the mean +/- SEM. The Student's t-test was used to compare the groups. A p value less than 0.05 was considered significant.

RESULTS

Of the study patients, 41 (16%) were children (ages 2-16, mean 10 years) and 210 (84%) were adults (ages 17-80, mean 34 years). The most common injury mechanisms in children were motor vehicle accidents (56%) and auto-pedestrian accidents (39%), but in adults, motor vehicle accidents (80%, p = 0.02) predominated. Injury severity score was not significantly different between groups (children, 26 +/- 2 and adults 25 +/- 1). Similarly, the incidence of associated injuries was not different between children and adults: head 78% versus 62%, abdomen 59% versus 43%, and skeletal fractures 41% versus 29%, respectively. Neither need for intubation, ventilator days, pneumonia, acute respiratory distress syndrome, or death differed significantly between groups.

CONCLUSIONS

Although children and adults differ in regard to injury mechanism, their overall injury severity, associated injuries, and outcomes are quite similar. Thus, contrary to previous reports, children do not have a more favorable outcome after PC.

Lipid mediators up-regulate CD11b and prime for concordant superoxide and elastase release in human neutrophils

BACKGROUND

The pathogenesis of multiple organ failure after injury is believed to involve priming and activation of the inflammatory cascade, and the polymorphonuclear neutrophil (PMN) appears to be an integral effector. Characterization of the primed PMN is evolving. Because much research has focused on the respiratory burst, the synergistic role of cytotoxic proteases, especially elastase, has been largely ignored. In addition, CD11b has been identified as pivotal in PMN-mediated tissue injury. Our hypothesis is that the well-recognized postinjury mediators platelet-activating factor (PAF) and leukotriene B4 (LTB4) prime PMNs for the concordant release of elastase and superoxide (O2-) as well as for CD11b up-regulation.

METHODS

Human PMNs were isolated and then incubated with PAF or LTB4 before N-formyl-methionyl-leucyl-phenylalanine activation. O2- generation was measured by reduction of cytochrome c. Elastase was measured by cleavage of Ala-Ala-Pro-Val p-nitroanilide. CD11b expression was quantified by incubation with R-phycoerythrin-labeled monoclonal antibodies followed by flow cytometry.

RESULTS

PAF and LTB4 primed PMNs maximally within 5 minutes for the production of O2-, elastase release, and simultaneous up-regulation of CD11b expression on the PMN surface.

CONCLUSION

PAF and LTB4 prime human PMNs for the concordant release of elastase, generation of O2-, and CD11b up-regulation. Understanding the physiologic characteristics of PMN priming may offer new therapeutic targets to avoid the development of multiple organ failure after injury.

Clinical utility of human polymerized hemoglobin as a blood substitute after acute trauma and urgent surgery

We have previously documented the safety of 1 unit (50 gram) of human polymerized hemoglobin (Poly SFH-P) in healthy volunteers. This report describes the first patient trial to assess the therapeutic benefit of Poly SFH-P in acute blood loss. Thirty-nine patients received 1 (n = 14), 2 (n = 2), 3 (n = 15), or 6 (n = 8) units of Poly SFH-P instead of red cells as part of their blood replacement after trauma and urgent surgery. There were no safety issues related to the infusion of Poly SFH-P. The plasma hemoglobin concentration ([Hb]) after the infusion of 6 units (300 gram) of Poly SFH-P was 4.8 +/- 0.8 g/dL (mean +/- SD). Although the red cell [Hb] fell to 2.9 +/- 1.2 g/dL, the total [Hb] was maintained at 7.5 +/- 1.2 g/dL. Poly SFH-P maintained total [Hb], despite the marked fall in red cell [Hb] due to blood loss. The utilization of O2 (extraction ratio) was 27 +/- 16% from the red cells and 37 +/- 13% from the Poly SFH-P. Twenty-three patients (59%) avoided allogeneic transfusions during the first 24 hours after blood loss. Poly SFH-P effectively loads and unloads O2 and maintains total hemoglobin in lieu of red cells after acute blood loss, thereby reducing allogeneic transfusions. Poly SFH-P seems to be a clinically useful blood substitute.

Blood transfusion. An independent risk factor for postinjury multiple organ failure

OBJECTIVE

To determine if blood transfusion is a consistent risk factor for postinjury multiple organ failure (MOF), independent of other shock indexes.

DESIGN

A 55-month inception cohort study ending on August 30, 1995. Data characterizing postinjury MOF were prospectively collected. Multiple logistic regression analysis was performed on 5 sets of data. Set 1 included admission data (age, sex, comorbidity, injury mechanism, Glasgow Coma Scale, Injury Severity Score, and systolic blood pressure determined in the emergency department) plus the amount of blood transfused within the first 12 hours. In the subsequent 4 data sets, other indexes of shock (early base deficit, early lactate level, late base deficit, and late lactate level) were sequentially added. Additionally, the same multiple logistic regression analyses were performed with early MOF and late MOF as the outcome variables.

SETTING

Denver General Hospital, Denver, Colo, is a regional level I trauma center.

PATIENTS

Five hundred thirteen consecutive trauma patients admitted to the trauma intensive care unit with an Injury Severity Score greater than 15 who were older than 16 years and who survived longer than 48 hours.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

The relationship of blood transfusions and other shock indexes with the outcome variable, MOF.

RESULTS

A dose-response relationship between early blood transfusion and the later development of MOF was identified. Despite the inclusion of other indexes of shock, blood transfusion was identified as an independent risk factor in 13 of the 15 multiple logistic regression models tested; the odds ratios were high, especially in the early MOF models.

CONCLUSIONS

Blood transfusion is an early consistent risk factor for postinjury MOF, independent of other indexes of shock.

Base deficit after major trauma directly relates to neutrophil CD11b expression: a proposed mechanism of shock-induced organ injury

OBJECTIVE

To determine whether expression of neutrophil integrin receptors is related to the degree of post-traumatic shock.

DESIGN

Data were collected prospectively on patients with major trauma admitted to the surgical intensive care unit.

SETTING

Denver General Hospital, Colorado.

PATIENTS AND PARTICIPANTS

17 severely injured adults.

MEASUREMENTS AND RESULTS

The mean fluorescence intensity and per cent positive of neutrophil integrin receptors CD11 b, CD18 and CD11 a, and systolic blood pressure, blood transfusion, lactate and base deficit as indices of shock. CD11 b expression on circulating neutrophils was increased 6 and 12 h after trauma. After correcting for the other shock indices, base deficit predicted CD11 b expression at 12 h. CD11 b expression was negatively correlated with the circulating neutrophil count.

CONCLUSIONS

The degree of metabolic acidosis after trauma correlates directly with CD11 b receptor expression on circulating neutrophils. This relation may be the mechanism whereby post-traumatic shock results in neutrophil sequestration and neutrophil-mediated organ injury and failure.

Circulating IL-1ra and IL-10 levels are increased but do not predict the development of acute respiratory distress syndrome in at-risk patients

Although numerous cytokines, including interleukin (IL)-1, IL-8, and tumor necrosis factor, circulate in critically ill patients at risk for acute respiratory distress syndrome (ARDS), none clearly predict the development of the syndrome. We hypothesized that cytokines, such as IL-1ra, IL-10, and IL-4, which modulate inflammation, might contribute to or reflect the development of acute lung injury. Accordingly, serial levels of IL-1ra and IL-10 were measured in 77 patients who were identifed as being at risk for the development of ARDS. Initial IL-1ra levels were significantly higher (p < 0.0001) in the patients (7.82 [2.29-38.01] ng/ml) than in normal control subjects (0.24 [0.24-0.34] ng/ml) but did not predict the development of ARDS. Initial IL-1ra levels, however, were greater (p = 0.038) in the patients who died (31.95 [3.02-65.06] ng/ml) compared with survivors (6.61 [1.86-29.33] ng/ml). Similarly, IL-10 levels were increased in patients (155 [53.75-318.75] ng/ml) compared with normal control subjects (0 ng/ml) but did not predict the development of ARDS. Like IL-1ra levels, initial IL-10 levels were significantly higher (p = 0.005) in patients who died compared with survivors. IL-4 was not detectable in any of the patient plasma samples measured. Thus, modulators of inflammation are increased in patients at risk for ARDS who die, but do not predict the development of the syndrome.

Evidence for early supply independent mitochondrial dysfunction in patients developing multiple organ failure after trauma

OBJECTIVE

To determine whether early supply independent mitochondrial oxidative dysfunction occurs in trauma patients who develop multiple organ failure (MOF).

DESIGN

Prospective focused observational trial.

METHODS

High-risk patients were aggressively resuscitated while being continuously monitored by near infrared spectroscopy. Near infrared spectroscopy monitoring strips allow for a direct comparison of changes in tissue oxyhemoglobin levels (HbO2), which reflect local oxygen supply, and cytochrome a,a3 redox, which reflects mitochondrial oxygen consumption. Under normal conditions, HbO2 and a,a3 redox are tightly coupled. On the other hand, decoupled HbO2 and a,a3 redox is a sign of mitochondrial oxidative dysfunction. Outcomes included MOF, oxygen delivery, oxygen consumption, lactate, and the presence of decoupled HbO2 and a,a3 redox.

RESULTS

Twenty-four high-risk patients were studied; nine (38%) developed MOF. At 12 hours of resuscitation, MOF and non-MOF patients did not have statistically different oxygen delivery and oxygen consumption, but lactate levels were significantly higher in MOF patients. Additionally, HBO2 and a,a3 redox were decoupled in eight (89%) MOF patients compared with two (13%) non-MOF patients (p < 0.05).

CONCLUSION

Severely injured trauma patients who develop MOF preferentially display evidence of mitochondrial oxidative dysfunction early in the course of their resuscitation despite early goal-oriented maximization of oxygen delivery.

Reduced PAF-acetylhydrolase activity is associated with postinjury multiple organ failure

Our basic laboratory work has identified the postischemic gut as a source of platelet-activating factor (PAF), which primes circulating neutrophils for the production of reactive oxygen metabolites (ROMs) leading to distant organ injury. Circulating PAF-acetylhydrolase (PAF-AH) hydrolyzes PAF to lyso-PAF. Recently, ROMs have been shown to rapidly and irreversibly inactivate human PAF-AH. Consequently, our study hypothesis was that reduced levels of PAF-AH in severely injured patients would be associated with the development of multiple organ failure (MOF). Over a 16 mo period, 26 patients at known risk for MOF (Injury Severity Score (ISS) > or = 25 or an ISS > 15 with > or = 6 U of blood transfused within the first 6 h) had blood sampled on postinjury days 0, 1, 2, 3, and 5. PAF-AH activity was assessed by measuring the percentage of 3H-labeled PAF hydrolyzed. MOF was defined by a standard score. The mean age of the 26 study patients was 34 +/- 2 yr; 19 (73%) were male. The injury mechanism was blunt in 18 (69%), and the mean ISS was 31 +/- 2. Eight patients (31%) developed MOF. In the MOF patients, plasma PAF-AH activity was significantly lower on the day of injury and remained depressed throughout the ensuing 5 days compared with the non-MOF patients. Reduced PAF-AH activity is associated with the development of postinjury MOF. With the recent molecular cloning of human plasma PAF-AH, repleting this circulating, anti-inflammatory enzyme may represent useful therapy for these high risk patients.

Serum ferritin as a predictor of the acute respiratory distress syndrome

We investigated serum ferritin levels as a predictor of the acute respiratory distress syndrome (ARDS) because: (1) proinflammatory cytokines, which are implicated in ARDS, increase ferritin synthesis; and (2) oxidative stress in patients at risk for ARDS might liberate iron from ferritin, accelerating toxic hydroxyl radical (.OH) formation. Serum ferritin levels measured by radioimmunoassay (RIA) were greater in 75 patients at risk for ARDS (women, p < 0.0001; men, p < 0.0001) and 8 patients with ARDS (women, p = 0.001; men, p = 0.0009) than in healthy control subjects. Serum ferritin levels were also greater in female (p = 0.003) and male (p = 0.003) at-risk patients who developed ARDS than in patients who did not develop ARDS. In women, a value exceeding 270 ng/ml predicted ARDS with an 83% sensitivity, 71% specificity, 67% positive, and 86% negative predictive value. In men, a value exceeding 680 ng/ml predicted ARDS with a 60% sensitivity, 90% specificity, 75% positive, and 82% negative predictive value. Serum ferritin levels did not correlate with C-reactive protein levels, were not different in medical or surgical at-risk patients, and were not accounted for by liver disease. Evaluating serum ferritin levels in at-risk patients may help predict the development of ARDS and thereby improve study and treatment of ARDS. Elevated serum ferritin levels may also regulate the participation of iron in the oxidative responses that contribute to ARDS.