Marko Bukur

Redefining hypotension in traumatic brain injury

BACKGROUND Systemic hypotension is a well documented predictor of increased mortality following traumatic brain injury (TBI). Hypotension is traditionally defined as systolic blood pressure (SBP)<90 mmHg. Recent evidence defines hypotension by a higher SBP in injured (non-TBI) trauma patients. We hypothesize that hypotension threshold requires a higher SBP in isolated moderate to severe TBI. PATIENTS AND METHODS A retrospective database review of all adults (≥ 15 years) with isolated moderate to severe TBI (head abbreviated injury score (AIS)≥ 3, all other AIS ≤ 3), admitted from five Level I and eight Level II trauma centres (Los Angeles County), between 1998 and 2005. Several fit statistic analyses were performed for each admission SBP from 60 to 180 mmHg to identify the model that most accurately defined hypotension for three age groups: 15-49 years, 50-69 years, and ≥ 70 years. The main outcome variable was mortality, and the optimal definition of hypotension for each group was determined from the best fit model. Adjusted odds ratios (AOR) were then calculated to determine increased odds in mortality for the defined optimal SBP within each age group. RESULTS A total of 15,733 patients were analysed. The optimal threshold of hypotension according to the best fit model was SBP of 110 mmHg for patients 15-49 years (AOR 1.98, CI 1.65-2.39, p<0.0001), 100 mmHg for patients 50-69 years (AOR 2.20, CI 1.46-3.31, p=0.0002), and 110 mmHg for patients ≥ 70 years (AOR 1.92, CI 1.35-2.74, p=0.0003). CONCLUSIONS Patients with isolated moderate to severe TBI should be considered hypotensive for SBP<110 mmHg. Further research should confirm this new definition of hypotension by correlation with indices of perfusion.

Influence of resident involvement on trauma care outcomes

HYPOTHESIS Discrepancies exist in complications and outcomes at teaching trauma centers (TTCs) vs nonteaching TCs (NTCs). DESIGN Retrospective review of the National Trauma Data Bank research data sets (January 1, 2007, through December 31, 2008). SETTING Level II TCs. PATIENTS Patients at TTCs were compared with patients at NTCs using demographic, clinical, and outcome data. Regression modeling was used to adjust for confounding factors to determine the effect of house staff presence on failure to rescue, defined as mortality after an in-house complication. MAIN OUTCOME MEASURES The primary outcome measures were major complications, in-hospital mortality, and failure to rescue. RESULTS In total, 162 687 patients were available for analysis, 36 713 of whom (22.6%) were admitted to NTCs. Compared with patients admitted to TTCs, patients admitted to NTCs were older (52.8 vs 50.7 years), had more severe head injuries (8.3% vs 7.8%), and were more likely to undergo immediate operation (15.0% vs 13.2%) or ICU admission (28.1% vs 22.8%) (P < .01 for all). The mean Injury Severity Scores were similar between the groups (10.1 for patients admitted to NTCs vs 10.4 for patients admitted to TTCs, P < .01). Compared with patients admitted to TTCs, patients admitted to NTCs experienced fewer complications (adjusted odds ratio [aOR], 0.63; P < .01), had a lower adjusted mortality rate (aOR, 0.87; P = .01), and were less likely to experience failure to rescue (aOR, 0.81; P = .01). CONCLUSIONS Admission to level II TTCs is associated with an increased risk for major complications and a higher rate of failure to rescue compared with admission to level II NTCs. Further investigation of the differences in care provided by level II TTCs vs NTCs may identify areas for improvement in residency training and processes of care.

Which central venous catheters have the highest rate of catheter-associated deep venous thrombosis: a prospective analysis of 2,128 catheter days in the surgical intensive care unit.

BACKGROUND Catheter-associated deep venous thromboses (CADVTs) are a common occurrence in the surgical intensive care unit (SICU), necessitating central venous catheter (CVC) removal and replacement. Previous studies evaluating risk factors for CADVT in SICU patients are limited, and most lack a true denominator of all CVC days. We sought to determine the true incidence of and risk factors for CADVT based on patient characteristics as well as CVC site, type, and duration of insertion. METHODS The following data from all SICU patients in two urban Level I trauma centers were prospectively collected from 2009 to 2012: demographics, risk factors for DVT, CVC site/type/duration, and duplex results. Sites included the subclavian (SC), internal jugular (IJ), arm (for peripherally inserted central catheter [PICC] lines), and femoral. Types included multilumen (ML), introducer/hemodialysis (I/HD), and PICC. High-risk patients received weekly screening duplex examinations and a CADVT was defined as a DVT being detected on duplex with a CVC in place or within 7 days of removal. Rates of CADVT were normalized per 1,000 CVC days, and independent predictors of CADVT were determined using logistic regression. RESULTS Data were complete for 184 patients, 354 CVCs, and 2,128 CVC days. Fifty-nine CADVTs were diagnosed in 28% of patients. Rates of CADVT were 9 per 1,000 catheter days for SC, 61 for IJ (p < 0.01 vs. SC), 27 for arm (p < 0.01), 36 for femoral (p < 0.01), 22 for ML, 57 for I/HD (p < 0.01 vs. ML), and 27 for PICC (p = 0.24). After adjusting for patient risk factors, predictors of CADVT included the IJ and arm sites (odds ratio, 6.0 and 3.0 compared with SC) and the I/HD type (odds ratio, 2.6 compared with ML, all p < 0.05). CONCLUSION The IJ and arm sites and I/HD type are associated with increased CADVT. These data may be used to determine the optimal site and type of CVC for insertion. LEVEL OF EVIDENCE Prognostic/epidemiologic study, level III.

Pre-hospital intubation is associated with increased mortality after traumatic brain injury.

BACKGROUND Early endotracheal intubation in patients sustaining moderate to severe traumatic brain injury (TBI) is considered the standard of care. Yet the benefit of pre-hospital intubation (PHI) in patients with TBI is questionable. The purpose of this study was to investigate the relationship between pre-hospital endotracheal intubation and mortality in patients with isolated moderate to severe TBI. METHODS The Los Angeles County Trauma System Database was queried for all patients > 14 y of age with isolated moderate to severe TBI admitted between 2005 and 2009. The study population was then stratified into two groups: those patients requiring intubation in the field (PHI group) and those patients with delayed airway management (No-PHI group). Demographic characteristics and outcomes were compared between groups. Multivariate analysis was used to determine the relationship between pre-hospital endotracheal intubation and mortality. RESULTS A total of 2549 patients were analyzed and then stratified into the two groups: PHI and No-PHI. There was a significant difference noted in overall mortality (90.2% versus 12.4%), with the PHI group being more likely to succumb to their injuries. After adjusting for possible confounding factors, multivariable logistic regression analysis demonstrated that PHI was independently associated with increased mortality (AOR 5, 95% CI: 1.7-13.7, P = 0.004). CONCLUSIONS Pre-hospital endotracheal intubation in isolated, moderate to severe TBI patients is associated with a nearly 5-fold increase in mortality. Further prospective studies are required to establish guidelines for optimal pre-hospital management of this critically injured patient population.

Self-inflicted penetrating injuries at a Level I Trauma Center.

INTRODUCTION Although gunshot and stab wounds are a common cause of self-inflicted injury, very little is understood about this mechanism of injury. The aim of this study was to characterise the epidemiology and outcomes of patients who injured themselves with a gun or sharp object. METHODS After IRB approval, the LAC+USC Trauma Registry was utilised to identify all patients who sustained a self-inflicted injury caused by firearm (GSW) or stabbing (SW) from 1997 to 2007. Demographic data, injury characteristics, surgical interventions, and outcomes were abstracted and analysed. RESULTS During the 11-year study period, a total of 753 patients (1.6%) were admitted for a self-inflicted injury. Of these, 369 (49.0%) had a self-inflicted penetrating injury, with 72 (19.5%) having sustained a GSW and 297 (80.5%) having a SW. Overall, the mean age was 36.4+/-15.8 years, 83.5% were male, with a mean ISS of 7.4+/-11.0. The most commonly injured body region in GSW patients was the head (76.4%), followed by the chest (15.3%) and in SW patients the upper extremity (37.0%), followed by the abdomen (36.4%). When compared to SW, GSW were significantly more frequent in males (21.4% vs. 9.8%, p=0.04), and were most commonly to the head (21.4% vs. 8.2%, p=0.02). Patients sustaining a GSW were more likely to be older than 55 years (22.2% vs. 8.4%, p<0.001). Intoxication was noted at presentation in 38.3% of screened GSW patients and 39.9% of SW patients. SW patients required operative intervention more frequently (40.9% vs. 22.2%, p<0.01), with 12.8% of them requiring exploratory laparotomy. However, patients who shot themselves were much more likely to die (66.7%) than those presenting with SW (1.7%). For those presenting with a GSW to the head, the mortality rate was even higher, at 80%. Mortality did not differ between males and females in either group. CONCLUSION Although a self-inflicted SW is far more common than a self-inflicted GSW, patients sustaining a GSW are more severely injured, and have a nearly 110-fold increased risk of death. Though less lethal, stab wounds still consume significant amounts of healthcare resources and incur large in-hospital costs. The average hospital charge incurred for treating these self-inflicted injuries was five times the amount spent per annum on American citizens. Self-inflicted penetrating injuries represent a golden opportunity for secondary prevention through psychiatric intervention. These interventions may not only preserve life but also improve resource utilisation.

Alcohol is associated with a lower pneumonia rate after traumatic brain injury.

BACKGROUND Recent evidence supports the beneficial effect of alcohol on patients with traumatic brain injury (TBI). Pneumonia is a known complication following TBI; thus, the purpose of this study was to evaluate the effects of alcohol on pneumonia rates following moderate to severe TBI. METHODS From 2005 to 2009, the Los Angeles County Trauma Database was queried for all patients ≥ 14 y of age with isolated moderate to severe TBI and admission serum alcohol levels. The incidence of pneumonia was compared between TBI patients with and without a positive blood alcohol concentration (BAC) level. The study population was then stratified into four BAC levels: None (0 mg/dL), low (0-100 mg/dL), moderate (100-230 mg/dL), and high (≥ 230 mg/dL). Pneumonia rates were compared across these levels. RESULTS A total of 3547 patients with isolated, moderate to severe TBI were evaluated. Nearly 66% tested positive for alcohol. The pneumonia rate was significantly lower in the TBI patients who tested positive for alcohol (2.5%) compared with those who tested negative (4.0%, P = 0.017). The pneumonia rate also decreased across increasing BAC levels (linear trend P = 0.03). After logistic regression analysis, a positive ethanol (ETOH) level was associated with a reduced incidence of pneumonia (AOR = 0.62; 95%CI: 0.41-0.93; P = 0.020). CONCLUSION A positive serum alcohol level was associated with a significantly lower pneumonia rate in isolated, moderate to severe TBI patients. This may explain the observed mortality reduction in TBI patients who test positive for alcohol. Additional research is warranted to investigate the potential therapeutic implications of this association.

Impact of prehospital hypothermia on transfusion requirements and outcomes.

BACKGROUND Prehospital hypothermia (PH) is known to increase mortality following traumatic injury. PH relationship with transfusion requirements has not been documented. The purpose of this investigation was to analyze the impact of PH on blood product requirements and subsequent outcomes. METHODS The Los Angeles County Trauma System Database was queried for all patients admitted between 2005 and 2009. Demographics, physiologic parameters, and transfusion requirements were obtained and dichotomized by admission temperatures with a core temperature of less than 36.5°C considered hypothermic. Multivariate analysis was performed to determine factors contributing to transfusion requirements and to derive adjusted odds ratios (AORs) for mortality and rates of adult respiratory distress syndrome and pneumonia. RESULTS A total of 21,023 patients were analyzed in our study with 44.6% presenting with PH. Hypothermic patients required 26% more fluid resuscitation (p < 0.001) in the emergency department and 17% more total blood products (p < 0.001) than those who were admitted with a normal temperature. There was a trend toward an increase in emergency department transfusion (8%, p = 0.06). PH was independently associated with the need for a transfusion (AOR, 1.1; p = 0.047), increased mortality (AOR, 2.0; p < 0.01), as well as incidence of adult respiratory distress syndrome (AOR, 1.8; p < 0.05) and pneumonia (AOR, 2.6; p < 0.01). CONCLUSION PH is associated with increased transfusion and fluid requirements and subsequently worse outcomes. Interventions that correct hypothermia may decrease transfusion requirements and improve outcomes. Prospective studies investigating correction of hypothermia in trauma patients are warranted. LEVEL OF EVIDENCE Prognostic/epidemiologic study, level III.

Beta-blocker exposure in the absence of significant head injuries is associated with reduced mortality in critically ill patients

BACKGROUND The effect of β-blockade in trauma patients without significant head injuries is unknown. The purpose of this investigation was to determine the impact of β-blocker exposure on mortality in critically injured trauma patients who did not sustain significant head injuries. METHODS Critically ill trauma patients (Injury Severity Score ≥ 25) admitted to the surgical intensive care unit from January 2000 to December 2008 without severe traumatic brain injuries (head Abbreviated Injury Score ≥ 3) were included in this retrospective review. Patients who received β-blockers within 30 days of intensive care unit admission were compared with those who did not. The primary outcome measure evaluated was in-hospital mortality. RESULTS During the 9-year study period, 663 critically injured patients (Injury Severity Score ≥ 25) were admitted to the intensive care unit. Of these, 98 patients (14.8%) received β-blockers. Patients exposed to β-blockers had significantly lower in-hospital mortality (11.2% vs 19.3%, P = .006). Stepwise logistic regression identified β-blocker use as an independent protective factor for mortality (adjusted odds ratio, .37; P = .007) in critically injured patients. CONCLUSIONS Beta-blocker exposure was associated with reduced mortality in critically injured patients without head injuries. Prospective validation of this finding is warranted.

Long-term effect of trauma splenectomy on blood glucose

BACKGROUND Increasing evidence suggests that the spleen harbors stem cells that act as precursors to insulin-producing pancreas cells. Additionally, small studies with short-term follow-up associate splenectomy with increased rates of diabetes mellitus. The purpose of this study was to analyze the long-term effect of trauma splenectomy on blood glucose. MATERIALS AND METHODS Patients were included if a blood glucose level was measured more than 5 y after trauma splenectomy or laparotomy with bowel repair. Mean blood glucose level was then compared between the two groups. RESULTS During the 10-y study period 61 patients underwent trauma splenectomy and 50 survived until discharge. In comparison, 229 patients underwent trauma laparotomy and bowel repair and 207 survived until discharge. Nine splenectomy patients compared with 12 control patients had, blood glucose measured at least 5 y after initial trauma. Mean follow-up period was not significantly different between groups (splenectomy 82.8 ± 17.6 mo versus control 96.0 ± 44.3 mo, P = 0.41). In the splenectomy cohort mean glucose level was significantly higher compared with the control (114 ± 34 mg/dL versus 90 ± 13 mg/dL, P = 0.04), as was the number of patients with recorded blood glucose level greater than 130 mg/dL (4 patient versus 0 patients P = 0.02). One new diagnosis of diabetes mellitus was noted only in the trauma splenectomy cohort. CONCLUSIONS This small study suggests that trauma splenectomy may be associated with hyperglycemia at long-term follow-up.

Elevated admission systolic blood pressure after blunt trauma predicts delayed pneumonia and mortality.

BACKGROUND Although avoiding hypotension is a primary focus after trauma, elevated systolic blood pressure (SBP) is frequently disregarded. The purpose of this study was to determine the association between elevated admission SBP and delayed outcomes after trauma. METHODS The Los Angeles County Trauma System Database was queried for all patients between 2003 and 2008 with blunt injuries who survived for at least 2 days after admission. Demographics and outcomes (pneumonia and mortality) were compared at various admission SBP subgroups (≥160 mm Hg, ≥170 mm Hg, ≥180 mm Hg, ≥190 mm Hg, ≥200 mm Hg, ≥210 mm Hg, and ≥220 mm Hg). Patients with moderate-to-severe traumatic brain injury (TBI), defined as head Abbreviated Injury Score ≥3, were then identified and compared with those without using multivariable logistic regression. RESULTS Data accessed from 14,382 blunt trauma admissions identified 2,601 patients with moderate-to-severe TBI (TBI group) and 11,781 without moderate-to-severe TBI (non-TBI group) who were hospitalized ≥2 days. Overall mortality was 2.9%, 7.1% for TBI patients, and 1.9% for non-TBI patients. Overall pneumonia was 4.6%, 9.5% for TBI patients, and 3.6% for non-TBI patients. Regression modeling determined SBP ≥160 mm Hg was a significant predictor of mortality in TBI patients (adjusted odds ratio [AOR], 1.59; confidence interval [CI], 1.10-2.29; p = 0.03) and non-TBI patients (AOR, 1.47; CI, 1.14-1.90; p = 0.003). Similarly, SBP ≥160 mm Hg was a significant predictor for increased pneumonia in TBI patients (AOR, 1.79; CI, 1.30-2.46; p = 0.0004), compared with non-TBI patients (AOR, 1.28; CI, 0.97-1.69; p = 0.08). CONCLUSIONS In blunt trauma patients with or without TBI, elevated admission SBP was associated with worse delayed outcomes. Prospective research is necessary to determine whether algorithms that manage elevated blood pressure after trauma, especially after TBI, affect mortality or pneumonia.