Faculty Bibliography

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.

BACKGROUND: Little focus is on health care disparities in the elderly, a population largely covered by public insurance. We characterized insurance type and race in elderly trauma patients to determine if lack of insurance or minority status predict increased mortality. METHODS: The National Trauma Data Bank (version 7.0) was queried for all adult blunt trauma patients. We divided patients into two cohorts (15-64 or >/= 65 years) based on age for universal Medicare eligibility. Our primary outcome measure was in-hospital mortality. Multiple logistic regression was used to control for confounding variables. RESULTS: A total of 541,471 patients met inclusion criteria. Among younger patients, the most common insurance type was private (41.0%), with 26.9% uninsured. In contrast, the most common insurance type among older patients was Medicare (64.6%), with 6.0% uninsured. Within the younger cohort, private insurance (adjusted odds ratio [AOR], 0.6; p < 0.01) and other insurance (AOR, 0.8; p < 0.01) predicted reduced mortality, while Medicare predicted similar mortality (AOR, 1.1; p = 0.18) compared with no insurance. Black race (AOR, 1.4; p < 0.01) and Hispanic ethnicity (AOR, 1.4; p < 0.01) predicted higher mortality compared with white race. Within the older cohort, no insurance predicted similar mortality as Medicare (AOR, 1.0; p = 0.43), private insurance (AOR, 1.0; p = 0.51), and other insurance (AOR, 1.0; p = 0.71). Hispanic ethnicity predicted increased mortality (AOR, 1.4; p < 0.01), while Asian race was protective (AOR, 0.7; p = 0.01) compared with white race. CONCLUSION: Elderly trauma patients present primarily with Medicare, while younger trauma patients are mostly privately insured; elderly patients are four times more likely to be insured. Disparities caused by lack of insurance and minority race are reduced in elderly trauma patients. LEVEL OF EVIDENCE: Epidemiologic/prognostic study, level III.

BACKGROUND: Alcohol intoxication in pediatric trauma is underappreciated. The aim of this study was to characterize alcohol screening rates in pediatric trauma. METHODS: The Los Angeles County Trauma System Database was queried for all patients aged /=10 years who require admission.

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 degrees 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.

BACKGROUND: The effect of beta-blockade in trauma patients without significant head injuries is unknown. The purpose of this investigation was to determine the impact of beta-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 beta-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 beta-blockers. Patients exposed to beta-blockers had significantly lower in-hospital mortality (11.2% vs 19.3%, P = .006). Stepwise logistic regression identified beta-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.

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 /= 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.

Previous investigations suggest outcome differences at Level I and Level II trauma centers. We examined use of intracranial pressure (ICP) monitors at Level I and Level II trauma centers after traumatic brain injury (TBI) and its effect on mortality. The 2007 to 2008 National Trauma Databank was reviewed for patients with an indication for ICP monitoring based on Brain Trauma Foundation (BTF) guidelines. Demographic and clinical outcomes at Level I and Level II centers were compared by regression modeling. Overall, 15,921 patients met inclusion criteria; 11,017 were admitted to a Level I and 4,904 to a Level II trauma center. Patients with TBI admitted to a Level II trauma center had a lower rate of Injury Severity Score greater than 16 (80 vs 82%, P<0.01) and lower frequency of head Abbreviated Injury Score greater than 3 (80 vs 82%, P<0.01). After regression modeling, patients with TBI admitted to a Level II trauma center were 31 per cent less likely to receive an ICP monitor (adjusted odds ratio [AOR], 0.69; P<0.01) and had a significantly higher mortality (AOR, 1.12; P<0.01). Admission to a Level II trauma center after severe TBI is associated with a decreased use of ICP monitoring in patients who meet BTF criteria as well as an increased mortality. These differences should be validated prospectively to narrow these discrepancies in care and outcomes between Level I and Level II centers.

BACKGROUND: Complications after inferior vena cava (IVC) injury, including venous thromboembolism (VTE), are expected, but the exact incidence is poorly defined. The purpose of this study is to examine the VTE rate following ligation versus repair of IVC injuries. MATERIALS AND METHODS: The California State Inpatient Database was queried for all adult patients (age >14 y) admitted between 2005 and 2008 with IVC injuries. Demographic data, mechanism of injury, operative technique (ligation versus repair), and outcomes were recorded. Outcomes were compared according to operative technique. RESULTS: A total of 308 patients with IVC injuries were evaluated. The study population was mostly male (81.2%), young (median age 24 y), and Hispanic (43.2%). Overall mortality was 37.3%. The mechanisms of injury included gunshot wounds (52.3%), stab wounds (14.0%), and motor vehicle collisions (14.9%). Associated injuries were present in 100% of cases, with duodenal injuries being the most common. The majority of injuries were managed by primary repair (76.6%), with ligation performed in 23.4%. Patients who underwent ligation had a longer hospital stay (median 9 versus 6 d, P = 0.04) and a trend towards a higher mortality (45.8% versus 34.8%, P = 0.10), with no difference in VTE rate (4.2% versus 1.7%, P > 0.99). CONCLUSIONS: As expected, IVC injuries carry a very high mortality rate and are always associated with other injuries. We demonstrated a surprisingly low rate of VTE after operative management for IVC injury, which was similar for patients undergoing ligation and repair.

BACKGROUND: We undertook the current study to determine the impact of elevated admission systolic blood pressure (SBP) on trauma patients without severe brain injury. MATERIALS AND METHODS: We conducted a retrospective review of the Los Angeles County Trauma System database to identify all patients with moderate to severe injuries (injury severity score >9) admitted between 2003 and 2008. Patients with head abbreviated injury score >3 were excluded. We divided the remaining patients into three age cohorts and conducted multivariate regression modeling at increasing SBP thresholds to identify independent predictors of mortality. RESULTS: A total of 23,931 patients met inclusion criteria. Overall mortality was 8.6% and it increased with age across the three groups. The admission SBP thresholds associated with significantly increased mortality in the young and middle-aged were >190 mm Hg (AOR 1.5, P = 0.04) and >180 mm Hg (AOR 1.5, P = 0.01), respectively. In the elderly, no admission SBP threshold was associated with significantly increased mortality. Interestingly, several elevated admission SBP thresholds were associated with significantly reduced mortality in the elderly (>150 mm Hg AOR 0.6, P < 0.01; >160 mm Hg AOR 0.6, P < 0.01; and >170 mm Hg AOR 0.7, P = 0.02). CONCLUSIONS: The admission SBP thresholds that predicted higher mortality for the young and middle-aged were >190 mm Hg and >180 mm Hg, respectively. Elderly trauma patients tolerated higher admission SBP than their younger counterparts and multiple elevated SBP thresholds were associated with significantly reduced mortality in the elderly.