Biomedical subjects

Peter Rhee

Publications and source records attributed to Peter Rhee.

At least 19 recordsLinked to original sources

PubMed2007

New developments in fluid resuscitation.

Hemorrhagic shock is the leading cause of death in civilian and military trauma. Effective hemorrhage control and optimal resuscitation are the main goals in the management of severely injured patients. This article addresses the changing trends in fluid resuscitation in regards to who, when, and how. Much of these changing trends are caused by the recognition that the current method of resuscitation with crystalloid fluids may not be optimal and may even have detrimental consequences. This article summarizes a number of studies that have evaluated the cellular toxicities of commonly used resuscitation fluids, to highlight the need for the development of new fluids.

Animals↗

PubMed2007

Tissue oxygen saturation predicts the development of organ dysfunction during traumatic shock resuscitation.

BACKGROUND: Near-infrared spectroscopy (NIRS) can continuously and noninvasively monitor tissue oxygen saturation (StO2) in muscle and may be an indicator of shock severity. Our purpose was to evaluate how well StO2 predicted outcome in high-risk torso trauma patients presenting in shock. METHODS: The primary outcome in this prospective study was multiple organ dysfunction syndrome (MODS). StO2 data were obtained upon hospital arrival and for 24 hours along with other known predictors of hypoperfusion and clinical outcomes. Clinicians were blinded to StO2 measurements. RESULTS: Seven Level I trauma centers enrolled 383 patients, 50 of whom developed MODS. Minimum StO2 performed similarly to maximum base deficit (BD) in discrimination of MODS patients. The sensitivity for both measures (StO2 cutoff = 75%; BD cutoff = 6 mEq/L) was 78%, the specificity was 34% to 39%, the positive predictive value was 18% to 20% and the negative predictive value was 88% to 91%. StO2 and BD were also comparable in predicting death. CONCLUSIONS: NIRS-derived muscle StO2 measurements perform similarly to BD in identifying poor perfusion and predicting the development of MODS or death after severe torso trauma, yet have the additional advantages of being continuous and noninvasive.

Adolescent↗

PubMed2006

Management and hospital outcomes of blunt renal artery injuries: analysis of 517 patients from the National Trauma Data Bank.

BACKGROUND: Blunt renal artery injuries are rare and no single trauma center can accumulate substantial experience for meaningful conclusions about optimal therapeutic strategies. The purpose of this study was to assess the incidence of renal artery injuries after different types of blunt trauma, and evaluate the current therapeutic approaches practiced by American trauma surgeons and the effect of various therapeutic modalities on hospital outcomes. STUDY DESIGN: This was a National Trauma Data Bank study including all blunt trauma admissions with renal artery injuries. Demographics, mechanism of injury, Injury Severity Score, Abbreviated Injury Score for each body area (head, chest, abdomen, extremities) injuries, type of management (nephrectomy, arterial reconstruction, or observation), time from admission to definitive treatment, and hospital outcomes (mortality, ICU, and hospital stay) were analyzed. Multiple and logistic regression analyses were used to examine the relationship between type of management and hospital outcomes. RESULTS: Of a total of 945,326 blunt trauma admissions, 517 patients (0.05%) had injuries to the renal artery. Of the 517 patients, the kidney was not explored in 376 (73%), 95 (18%) patients had immediate nephrectomy, and 45 (9%) patients underwent surgical revascularization. In 87 of 517 (17%) patients, renal artery injury was the only intraabdominal injury. Of the 87 patients with isolated renal artery injuries, 73 (84%) were observed, 7 (8%) underwent surgical revascularization, and 7 (8%) had early nephrectomy. Multiple regression analysis demonstrated that patients who had surgical revascularization had a considerably longer ICU and hospital stay than observed patients. Patients who had nephrectomy had a considerably longer hospital stay than observed patients. CONCLUSIONS: Blunt renal artery injury is rare. Nonoperative management should be considered as an acceptable therapeutic option.

Abdominal Injuries↗

PubMed2006

Near-hanging injuries: a 10-year experience.

OBJECTIVE: To review the injury patterns and analyse outcomes in patients who present after near-hanging. METHODS: This is a trauma registry study that included all patients who were admitted to an academic Level I trauma centre with the diagnosis of attempted suicide by hanging between January 1993 and December 2003. All patients who were dead on arrival or in cardiopulmonary arrest were excluded. Data regarding demographics, injuries, and outcomes were examined. Independent risk factors for poor outcome were identified. RESULTS: During the 10-year study period, 63 patients were admitted after near-hanging. A total of 12 patients (19%) had 17 injuries. Cervical spine fractures occurred in nearly 5% of cases. Four factors were found to be significantly associated with poor outcome: systolic blood pressure <90, Glasgow coma score < or =8, anoxic brain injury on computed tomography (CT) scan, and injury severity score >15. However, logistic regression analysis found only anoxia on CT scan to be independently associated with poor outcome (p < 0.01). CONCLUSION: Injuries commonly occurred after near-hanging. Liberal screening using CT scans is warranted. The prognosis is favorable, even with patients who arrive with a GCS < or =8. Overall survival was 90% and only 3.5% were discharged with severe or permanent disability.

Adolescent↗

PubMed2006

Use of computed tomography in anterior abdominal stab wounds: results of a prospective study.

HYPOTHESIS: Computed tomography (CT) can be used to evaluate patients with anterior abdominal stab wounds (AASWs). DESIGN: Prospective observational study. SETTING: Academic level I trauma center. PATIENTS AND METHODS: All of the patients sustaining AASWs, excluding those with hemodynamic instability, peritonitis, or omental evisceration, were admitted for serial abdominal examinations with or without CT depending on attending preference. Patients with associated left thoracoabdominal stab wounds underwent diagnostic laparoscopy. MAIN OUTCOME MEASURES: Change in patient management as a direct result of the CT scan findings, as well as sensitivity, specificity, positive predictive value, and negative predictive value of CT scanning calculated against clinical outcome (the need for laparotomy, uneventful discharge without laparotomy, or return to the hospital for adverse events). RESULTS: One hundred fifty-six consecutive patients with AASWs were included over 24 months. Computed tomography was performed for 67 patients (CT group) whereas 89 patients were admitted for serial examination only (no-CT group). Nineteen of the 67 patients in the CT group had positive CT results, leading to laparotomy in 10 patients. Of the 48 patients with negative CT results, 3 underwent diagnostic laparoscopy for an associated thoracoabdominal stab wound and 2 eventually underwent laparotomy for clinical deterioration with negative results. Excluding patients with associated thoracoabdominal stab wounds, the negative predictive value of CT was 100%. CONCLUSIONS: In patients with AASWs, CT can be used to identify visceral injuries. It is a promising tool that may identify patients who can be discharged after a shorter period of observation. Further evaluation of its use in patients with AASWs is warranted.

Abdominal Injuries↗

PubMed2006

The impact of obesity on severely injured children and adolescents.

PURPOSE/BACKGROUND: In conjunction with the obesity epidemic in adults, we are starting to see an increase of obesity in children and adolescents. Obesity has been identified as risk factor for poor outcomes in adult trauma patients, but has not been investigated adequately in younger patients. The purpose of this study was to investigate the impact of obesity on the outcomes of a severely injured population of children and adolescents. METHODS: Retrospective review of traumatized children (age 6-12) and adolescents (age 13-19) admitted to the intensive care unit (ICU) at an urban, level I trauma center from 1998 to 2003. The trauma registry and ICU database were used for data acquisition. Height and weight were recorded for each patient upon admission to the ICU and used to calculate body mass index (BMI). Patients were categorized as either lean (BMI <95th percentile for age) or obese (BMI > or =95th percentile for age). The two groups were compared regarding admission demographics, vital signs, mechanism of injury, patterns of injury, Injury Severity Score, and operations required. Outcomes evaluated were need for and length of mechanical ventilation, complications, length of hospital and ICU stay, and mortality. RESULTS: There were 316 pediatric and adolescent trauma patients (262 [83%] lean, mean BMI = 23 kg/m2 and 54 [17%] obese, mean BMI = 33 kg/m2) admitted to the ICU. The lean and obese groups were similar regarding age, sex, mechanism of injury, admission vitals, injury severity, and operations required. Injury patterns were similar, except obese patients had less severe head injuries. Although there was no difference in mortality among obese (15%) and non-obese (9%) patients (P = .39), obese children did have more complications (41% vs 22%, P = .04). In addition, obese patients required longer ICU stays (8 +/- 9 vs 6 +/- 6 days, P = .05) after severe trauma. CONCLUSIONS: Despite similar admission characteristics and less severe head injuries, obese children and adolescents have more complications and require longer ICU stays than their lean counterparts.

Adolescent↗

PubMed2006

Angiography and the pediatric trauma patient: a 10-year review.

BACKGROUND/PURPOSE: Although interventional radiology has played an increasing role in the management of adult trauma patients, little has been written regarding its application in the care of the injured child. This study analyzed the indications, results, and complications for angiography in pediatric trauma patients. METHODS: A retrospective review of pediatric patients (14 years or younger) admitted to Los Angeles County-University of Southern California Medical Center, Los Angeles, Calif (an urban level I trauma center), over a 10-year period (1993-2003) was performed. Patients who underwent angiography were identified using hospital angiography records, and further information was recorded from the trauma registry and medical records. Variables collected included age, sex, mechanism of injury, and injury severity score (ISS). Angiographic data analyzed included indications, results, therapeutic interventions, and procedure-related complications. RESULTS: Twenty-five pediatric trauma patients who underwent angiography were identified (18 boys, 7 girls). The average age was 11 years (range, 1-14 years), with an ISS of 16 +/- 10. Indications for angiography included suspected limb ischemia (n = 9), suspected pelvic (n = 8) or solid organ bleeding (n = 8), suspected aortic injury (n = 6), and expanding hematoma (n = 1). Eleven patients (44%) had an abnormal finding, and 10 of 11 underwent a subsequent therapeutic intervention. There was 1 minor procedure-related complication and no procedure-related mortality. CONCLUSIONS: Though used infrequently in pediatric trauma patients, the result of the angiography was abnormal in almost half of the children in this series. An abnormal finding prompted further therapeutic intervention in most cases. Angiography was associated with minimal morbidity and should be considered as a useful and safe adjunct when caring for injured children.

Angiography↗

PubMed2006

Cardiac histones are substrates of histone deacetylase activity in hemorrhagic shock and resuscitation.

BACKGROUND: DNA transcription is regulated, in part, by acetylation of nuclear histones that are controlled by 2 groups of enzymes: histone deacetylases (HDAC) and histone acetyl transferases (HAT). Whether an imbalance in HDAC/HAT system plays a role in hemorrhage/resuscitation is unknown. The goals of this study were to determine whether hemorrhage results in deacetylation of cardiac histones and whether this can be corrected through the application of different resuscitation strategies or specific HDAC inhibitors. METHODS: In the first experiment, rats (n = 6 per group) were subjected to volume-controlled hemorrhage and resuscitated with racemic lactated Ringer's solution, L-lactated Ringer's solution, 7.5% hypertonic saline solution, ketone Ringer's solution, and pyruvate Ringer's solution. Control groups included no hemorrhage (sham) and hemorrhage with no resuscitation. In the second experiment (n = 5 per group), 3 HDAC inhibitors (valproic acid, trichostatin A, and suberoylanilide hydroxamic acid) were added to saline solution resuscitation. Heart tissue was collected at the end of resuscitation. Isolated subcellular protein fractions were used in Western blotting to analyze the patterns of total protein acetylation and histone acetylation specifically. HDAC and HAT activity was measured in tissue extracts. RESULTS: Hemorrhage led to partial histone deacetylation. Resuscitation resulted in protein hyperacetylation in nuclear fractions only. A detailed analysis of histones (on 10 acetylation sites) revealed that ketone Ringer's solution hyperacetylated histones H2B, H3, and H4. The addition of suberoylanilide hydroxamic acid hyperacetylated histones more effectively than other resuscitation strategies, presumably by direct inhibition of HDAC activity. CONCLUSION: Hemorrhage/resuscitation is associated with HDAC/HAT activity misbalance, and the acetylation status of cardiac histones is influenced by the choice of resuscitation strategy. Shock-induced changes can be reversed through the infusion of pharmacologic HDAC inhibitor, even when it is administered after the insult for a limited period of time.

Acetylation↗

PubMed2006

Profound hypothermia is superior to ultraprofound hypothermia in improving survival in a swine model of lethal injuries.

BACKGROUND: Rapid induction of profound hypothermia can improve survival from uncontrolled lethal hemorrhage. However, the optimal depth of hypothermia in this setting remains unknown. This experiment was designed to compare the impact of deep (15 degrees C), profound (10 degrees C), and ultraprofound (5 degrees C) hypothermia on survival and organ functions. METHODS: Uncontrolled lethal hemorrhage was induced in 32 swine (80-120 lb) by creating an iliac artery and vein injury, followed 30 minutes later by laceration of the descending thoracic aorta. Hypothermia was induced rapidly (2 degrees C/min) by infusing cold organ preservation solution into the aorta through a thoracotomy. The experimental groups were (n = 8 per group): a normothermic control, and 3 hypothermic groups in which the core temperature was reduced to 15 degrees C, 10 degrees C, and 5 degrees C. Vascular injuries were repaired during 60 minutes of hypothermia. Animals were then rewarmed (0.5 degrees C/min) and resuscitated on cardiopulmonary bypass, and monitored for 6 weeks for neurologic deficits, cognitive function, and organ dysfunction. RESULTS: All normothermic animals died, whereas 6-week survival rates for the 15 degrees C, 10 degrees C, and 5 degrees C groups were 62.5%, 87.5%, and 25%, respectively (P < .05: normothermic vs 15 degrees C and 10 degrees C; 10 degrees C vs 5 degrees C). The surviving animals from the 15 degrees C and 10 degrees C groups were neurologically intact, displayed normal learning capacity, and had no long-term organ dysfunction. The survivors from the 5 degrees C group displayed slower recovery and impaired cognitive functions. CONCLUSIONS: In a model of lethal injuries, rapid induction of profound hypothermia can prevent death. The depth of hypothermia influences survival, with a better outcome associated with a core temperature of 10 degrees C compared with 5 degrees C.

Animals↗

PubMed2006

Selective nonoperative management of penetrating abdominal solid organ injuries.

OBJECTIVE: To assess the feasibility and safety of selective nonoperative management in penetrating abdominal solid organ injuries. BACKGROUND: Nonoperative management of blunt abdominal solid organ injuries has become the standard of care. However, routine surgical exploration remains the standard practice for all penetrating solid organ injuries. The present study examines the role of nonoperative management in selected patients with penetrating injuries to abdominal solid organs. PATIENTS AND METHODS: Prospective, protocol-driven study, which included all penetrating abdominal solid organ (liver, spleen, kidney) injuries admitted to a level I trauma center, over a 20-month period. Patients with hemodynamic instability, peritonitis, or an unevaluable abdomen underwent an immediate laparotomy. Patients who were hemodynamically stable and had no signs of peritonitis were selected for further CT scan evaluation. In the absence of CT scan findings suggestive of hollow viscus injury, the patients were observed with serial clinical examinations, hemoglobin levels, and white cell counts. Patients with left thoracoabdominal injuries underwent elective laparoscopy to rule out diaphragmatic injury. Outcome parameters included survival, complications, need for delayed laparotomy in observed patients, and length of hospital stay. RESULTS: During the study period, there were 152 patients with 185 penetrating solid organ injuries. Gunshot wounds accounted for 70.4% and stab wounds for 29.6% of injuries. Ninety-one patients (59.9%) met the criteria for immediate operation. The remaining 61 (40.1%) patients were selected for CT scan evaluation. Forty-three patients (28.3% of all patients) with 47 solid organ injuries who had no CT scan findings suspicious of hollow viscus injury were selected for clinical observation and additional laparoscopy in 2. Four patients with a "blush" on CT scan underwent angiographic embolization of the liver. Overall, 41 patients (27.0%), including 18 cases with grade III to V injuries, were successfully managed without a laparotomy and without any abdominal complication. Overall, 28.4% of all liver, 14.9% of kidney, and 3.5% of splenic injuries were successfully managed nonoperatively. Patients with isolated solid organ injuries treated nonoperatively had a significantly shorter hospital stay than patients treated operatively, even though the former group had more severe injuries. In 3 patients with failed nonoperative management and delayed laparotomy, there were no complications. CONCLUSIONS: In the appropriate environment, selective nonoperative management of penetrating abdominal solid organ injuries has a high success rate and a low complication rate.

Abdominal Injuries↗

PubMed2006

Cervical spine injury is highly dependent on the mechanism of injury following blunt and penetrating assault.

BACKGROUND: The mechanism of injury has not been highly regarded as an important variable when evaluating cervical spine injuries. The aim of this study was to determine the incidence of cervical spine fracture (CSF) and cervical spinal cord injury (CSCI) based on mechanism following blunt and penetrating assault to better aid prioritization of management. METHODS: Retrospective analysis from two large urban Level I trauma centers over 87 and 144 months caused by gunshot wounds (GSW), stab wounds (SW) or blunt assault (BA). RESULTS: During the study period, there were 57,532 trauma patients evaluated at the two trauma centers, of which 42.3% were following blunt or penetrating assault. The rates of CSF and CSCI for the various mechanisms were similar between the two centers. The rates for having CSF were significantly different (p < 0.05) for the various mechanisms. GSW (1.35%) was the highest followed by BA (0.41%) and then SW (0.12%). The rates of CSCI for GSW (0.94%) were significantly (p < 0.05) higher than BA (0.14%) and SW (0.11%). For GSW patients, all patients with CSF or CSCI had a point of entry between the ears and the nipple. For SW patients, the wound was directly in the neck below the mandible and above the trapezius muscle. Although many of the SW patients also suffered blunt assault, none of the CSF or CSCI injuries were from blunt forces. In addition, all patients, both blunt and penetrating who had CSCI had neurologic deficit at the time of presentation. Surgical stabilization or tongs were applied in 15.5% (26 of 168) of the GSWs, 27.8% (3 of 11) of the SWs and 31.6% (6 of 19) of the BA patients. There was a BA patient (1 of 4,390) patient with CSF that was neurologically intact that required surgical stabilization and this patient had neck pain on admission. No penetrating injury patients with CSCI regained significant neurologic recovery during the hospitalization. SUMMARY: The rate of CSF or CSCI is low following assault and dependent on mechanism of injury. Thus the concern and extent of evaluation should also be dependent on the mechanism of injury. Neurologic deficits from penetrating assault were established and final at the time of presentation. Concern for protecting the neck should not hinder the evaluation process or life saving procedures.

Adult↗

PubMed2006

Tactical surgical intervention with temporary shunting of peripheral vascular trauma sustained during Operation Iraqi Freedom: one unit's experience.

BACKGROUND: Rapidly restoring perfusion to injured extremities is one of the primary missions of forward military surgical teams. The austere setting, limited resources, and grossly contaminated nature of wounds encountered complicates early definitive repair of complex combat vascular injuries. Temporary vascular shunting of these injuries in the forward area facilitates rapid restoration of perfusion while allowing for deferment of definitive repair until after transport to units with greater resources and expertise. METHODS: Standard Javid or Sundt shunts were placed to temporarily bypass complex peripheral vascular injuries encountered by a forward US Navy surgical unit during a six month interval of Operation Iraqi Freedom. Data from the time of injury through transfer out of Iraq were prospectively recorded. Each patient's subsequent course at Continental US medical centers was retrospectively reviewed once the operating surgeons had returned from deployment. RESULTS: Twenty-seven vascular shunts were used to bypass complex vascular injuries in twenty combat casualties with a mean injury severity score of 18 (range 9-34) and mean mangled extremity severity score of 9 (range 6-11). All patients survived although three (15%) ultimately required amputation for nonvascular complications. Six (22%) shunts clotted during transport but an effective perfusion window was provided even in these cases. CONCLUSION: Temporary vascular shunting appears to provide simple and effective means of restoring limb perfusion to combat casualties at the forward level.

Adolescent↗

PubMed2006

Does the rate of rewarming from profound hypothermic arrest influence the outcome in a swine model of lethal hemorrhage?

BACKGROUND: Rapid induction of profound hypothermic arrest (suspended animation) can provide valuable time for the repair of complex injuries and improve survival. The optimal rate for re-warming from a state of profound hypothermia is unknown. This experiment was designed to test the impact of different warming rates on outcome in a swine model of lethal hemorrhage from complex vascular injuries. METHODS: Uncontrolled lethal hemorrhage was induced in 40 swine (80-120 lbs) by creating an iliac artery and vein injury, followed 30 minutes later (simulating transport time) by laceration of the descending thoracic aorta. Through a thoracotomy approach, a catheter was placed in the aorta and hyperkalemic organ preservation solution was infused on cardiopulmonary bypass to rapidly (2 degrees C/min) induce profound (10 degrees C) hypothermia. Vascular injuries were repaired during 60 minutes of hypothermic arrest. The 4 groups (n = 10/group) included normothermic controls (NC) where core temperature was maintained between 36 to 37 degrees C, and re-warming from profound hypothermia at rates of: 0.25 degrees C/min (slow), 0.5 degrees C/min (medium), or 1 degrees C/min (fast). Hyperkalemia was reversed during the hypothermic arrest period, and blood was infused for resuscitation during re-warming. After discontinuation of cardiopulmonary bypass, the animals were recovered and monitored for 6 weeks for neurologic deficits, cognitive function (learning new skills), and organ dysfunction. Detailed examination of brains was performed at 6 weeks. RESULTS: All the normothermic animals died, whereas survival rates for slow, medium and fast re-warming from hypothermic arrest were 50, 90, and 30%, respectively (p < 0.05 slow and medium warming versus normothermic control, p < 0.05 medium versus fast re-warming). All the surviving animals were neurologically intact, displayed normal learning capacity, and had no long-term organ dysfunction. CONCLUSIONS: Rapid induction of hypothermic arrest maintains viability of brain during repair of lethal vascular injuries. Long-term survival is influenced by the rate of reversal of hypothermia.

Animals↗

PubMed2006

Hepatic and pulmonary apoptosis after hemorrhagic shock in swine can be reduced through modifications of conventional Ringer's solution.

BACKGROUND: Cytotoxic properties of racemic (D-,L-isomers) lactated Ringer's solution detected in vitro and in small animal experiments, have not been confirmed in large animal models. Our hypothesis was that in a clinically relevant large animal model of hemorrhage, resuscitation with racemic lactated Ringer's solution would induce cellular apoptosis, which can be attenuated by elimination of d-lactate. METHODS: Yorkshire swine (n = 49, weight 40-58 kg) were subjected to uncontrolled (iliac arterial and venous injuries) and controlled hemorrhage, totaling 40% of estimated blood volume. They were randomized (n = 7/group) to control groups, which consisted of (1) no hemorrhage (NH), (2) no resuscitation (NR), or resuscitation groups, which consisted of (3) 0.9% saline (NS), (4) racemic lactated Ringer's (DL-LR), (5) L-isomer lactated Ringer's (L-LR), (6) Ketone Ringer's (KR), (7) 6% hetastarch in 0.9% saline (Hespan). KR was identical to LR except for equimolar substitution of lactate with beta-hydroxybutyrate. Resuscitation was performed in three phases, simulating (1) prehospital, (2) operative, (3) postoperative/recovery periods. Arterial blood gasses, circulating cytokines (TNF-alpha, IL-1, -6, -10), and markers of organ injury were serially measured. Metabolic activity of brain, and liver, was measured with microdialysis. Four hours postinjury, organs were harvested for Western blotting, ELISA, TUNEL assay, and immunohistochemistry. RESULTS: All resuscitation strategies restored blood pressure, but clearance of lactic acidosis was impeded following DL-LR resuscitation. Metabolic activity decreased during shock and improved with resuscitation, without any significant inter-group differences. Levels of cytokines in circulation were similar, but tissue levels of TNF in liver and lung increased six- and threefolds (p < 0.05) in NR group. In liver, all resuscitation strategies significantly decreased TNF levels compared with the NR group, but in the lung resuscitation with lactated Ringer (DL and L isomers) failed to decrease tissue TNF levels. DL-LR resuscitation also increased apoptosis (p < 0.05) in liver and lung, which was not seen after resuscitation with other solutions. CONCLUSIONS: In this large animal model of hemorrhagic shock, resuscitation with conventional (racemic) LR solution increased apoptotic cell death in liver and lung. This effect can be prevented by simple elimination of D-lactate from the Ringer's solution.

Animals↗

PubMed2006

Obesity and traumatic brain injury.

BACKGROUND: As obesity continues to run rampant in our society, an understanding of its adverse effect after traumatic injury is starting to unfold. We hypothesize that obesity negatively impacts head-injured patients, and the current study intends to compare obese and lean patients with traumatic brain injury (TBI). METHODS: This is a retrospective study evaluating all blunt trauma patients with TBI admitted to the intensive care unit (ICU) in our urban, Level I trauma center from 1998 until 2003. Body mass index (BMI) was used to categorize patients as either lean (BMI <30 kg/m2) or obese (BMI > or =30 kg/m2). Admission demographics, type and severity of head injury, and associated injuries were recorded for each patient. Primary outcome was mortality, while secondary outcomes were cause of death, complications, and for survivors, days of mechanical ventilation, ICU length of stay, and hospital length of stay. Obese and lean patients were compared using univariate analysis and multivariate stepwise logistic regression. In addition, a subgroup analysis of patients with isolated head injury was performed. RESULTS: There were 690 patients with TBI admitted to the ICU during the study period, with 129 (19%) obese patients (BMI = 34 +/- 5 kg/m2) and 561 (81%) lean patients (BMI = 24 +/- 4 kg/m2). The two groups were similar with the exceptions that obese patients were older (46 +/- 20 years versus 39 +/- years, p < 0.01), had lower admission systolic blood pressure (125 +/- 38 mm Hg versus 134 +/- 30 mm Hg, p = 0.01), and more often sustained an associated chest injury (46% versus 35%, p = 0.03). Obese patients with TBI had a trend toward more complications (34% versus 28%, p = 0.17) and a higher mortality (36% versus 25%, p = 0.02). However, stepwise logistic regression failed to identify obesity as an independent risk factor for either morbidity or mortality. In addition, obese patients with isolated head injury had no increase in complications or death. CONCLUSIONS: Although obese patients suffer more complications and higher mortality than lean patients after TBI, this adverse effect seems to be due to age, lower admission blood pressure, and more associated chest injury, rather than a direct result of the obese state.

Adult↗

PubMed2006

Identification of expression patterns associated with hemorrhage and resuscitation: integrated approach to data analysis.

BACKGROUND: Although transcriptional profiling is a well-established technique, its application to systematic studying of various biological phenomena is still limited because of problems with high-volume data analysis and interpretation. This research project's objective was to create a comprehensive summary of changes in gene expression after hemorrhagic shock (HS), reliant and impartial of multiple variables, such as resuscitation treatments, organ analyzed, and time after impact. METHODS: Rat model of severe (40% total blood loss) HS was employed. Hemorrhagic shock was treated with 6 different resuscitation strategies: (1) racemic lactated Ringer's (DL-LR); (2) L-lactated Ringer's (L-LR); (3) ketone Ringer's (KR); (4) pyruvate Ringer's (PR); (5) 6% hetastarch (Hex); (6) 7.5% hypertonic saline (HTS). Nonresuscitated and nonhemorrhaged rats served as controls. Ketone and pyruvate Ringer solutions were identical to the lactated Ringer's solution except for equimolar substitution of lactate with beta-hydroxybutyrate and sodium pyruvate, respectively. Total RNA from liver, lung, and spleen was isolated immediately (0 hour) and 24 hour postresuscitation. Each organ, time point and treatment was profiled using individual cDNA array (1,200 genes), to produce 183 separate data files. Methods of analysis included one-way and unbalanced factorial ANOVA, Sokal-Michener average linkage clustering and contextual mapping. RESULTS: : Unresuscitated HS produced the highest number (56) of upregulated expressions in spleen and lungs. HEX and HTS affected mostly pulmonary genes (22 and 9). Fourteen genes changed in response to combination of all three factors: treatment, organ, and time. Eighteen genes were identified as treatment-specific. Fifteen genes adjusted expression 24 hour post-treatment. The largest number of genes with altered expression (168) responded differently in all three organs. In this study 15 gene clusters were pinpointed. Contextual mapping identified novel and confirmed known pathways contributing to hemorrhage/resuscitation. CONCLUSIONS: We have reliably identified genes and pathways that are affected by HS and are responsive to resuscitation. Gene expression in various organs is affected differentially by HS, which can be further modulated by the choice of resuscitation strategy.

Analysis of Variance↗

PubMed2006

Early prediction of mortality in isolated head injury patients: a new predictive model.

BACKGROUND: To construct a predictive model of survival in isolated head injury patients, on the basis of easily available parameters that are independent risk factors for survival outcome. METHODS: Trauma registry-based study of head injury patients who had no other major extracranial injuries and were not hypotensive at admission. A predictive model of probability of death was constructed using discriminant analysis, on the basis of admission Glasgow Coma Scale (GCS) score, head Abbreviated Injury Score (AIS), age, and mechanism of injury. RESULTS: The study included 7,191 patients with head trauma. The overall correct classification rate of the proposed predictive model was 94.2% as compared with 89.0% of the admission GCS score (p < 0.05) and 92.8% of the head AIS (p < 0.05). The correct classification rate of the predictive model developed for the severe head trauma (GCS score 4-8) patients was 79.9%, as compared with 72.6% using the admission GCS score alone or 75.1% (p < 0.05). A one-page, easy to use table summarizing the predicted mortality on the basis of GCS score, head AIS, mechanism of injury, and age was developed. CONCLUSIONS: The proposed model has a significantly better predictive power, especially in severe head trauma, than the extensively used GCS and head AIS. A simple table on the probability of death of a particular patient based on admission GCS score, head AIS, mechanism of injury and age of patient can provide instant information.

Abbreviated Injury Scale↗

PubMed2006

The experience of the US Marine Corps' Surgical Shock Trauma Platoon with 417 operative combat casualties during a 12 month period of operation Iraqi Freedom.

BACKGROUND: The Forward Resuscitative Surgical System (FRSS) is a small, mobile trauma surgical unit designed to support modern US Marine Corps combat operations. The experience of two co-located FRSS teams during 1 year of service in Operation Iraqi Freedom is reviewed to evaluate the system's efficacy. METHODS: Between March 1, 2004, and February 28, 2005, two FRSS teams and a shock trauma platoon were co-located in a unit designated the Surgical Shock Trauma Platoon (SSTP). Data concerning patient care before and during treatment at the SSTP was maintained prospectively. Prospective determination of outcomes was obtained by e-mail correspondence with surgeons caring for the patients at higher echelons. The Los Angeles County medical center (LAC) trauma registry was queried to obtain a comparable data-base with which to compare outcomes. RESULTS: During the year reviewed there were 895 trauma admissions to the SSTP. Excluding 25 patients pulseless on arrival and 291 minimally injured patients, 559 of 579 (97%) combat casualties survived; 417 casualties underwent 981 operative procedures in the two SSTP operating shelters. There were 79 operative patients with a mean injury severity score of 26 (range, 16-59) and mean revised trauma score of 6.963 (range, 4.21-7.841) who had sustained severe injuries. Ten (12.7%) of these casualties died while 43 of 337 (12.8%) deaths were seen with comparable cases treated at LAC. CONCLUSIONS: Small task-oriented surgical units are capable of providing effective trauma surgical care to combat casualties. Further experience is needed to better delineate the balance between early, forward-based surgical intervention and more prolonged initial casualty evacuation to reach more robust surgical facilities.

Adult↗