Transcranial Doppler investigation of hemodynamic alterations associated with blunt cervical vascular injuries in trauma patients.

OBJECTIVES: Blunt cervical vascular injuries, often missed with current screening methods, have substantial morbidity and mortality, and there is a need for improved screening. Elucidation of cerebral hemodynamic alterations may facilitate serial bedside monitoring and improved management. Thus, the objective of this study was to define cerebral flow alterations associated with single blunt cervical vascular injuries using transcranial Doppler sonography and subsequent Doppler waveform analyses in a trauma population. METHODS: In this prospective pilot study, patients with suspected blunt cervical vascular injuries had diagnoses by computed tomographic angiography and were examined using transcranial Doppler sonography to define cerebral hemodynamics. Multiple vessel injuries were excluded for this analysis, as the focus was to identify hemodynamic alterations from isolated injuries. The inverse damping factor characterized altered extracranial flow patterns; middle cerebral artery flow velocities, the pulsatility index, and their asymmetries characterized altered intracranial flow patterns. RESULTS: Twenty-three trauma patients were evaluated: 4 with single internal carotid artery injuries, 5 with single vertebral artery injuries, and 14 without blunt cervical vascular injuries. All internal carotid artery injuries showed a reduced inverse damping factor in the internal carotid artery and dampened ipsilateral mean flow and peak systolic velocities in the middle cerebral artery. Vertebral artery injuries produced asymmetry of a similar magnitude in the middle cerebral artery mean flow velocity with end-diastolic velocity alterations. CONCLUSIONS: These data indicate that extracranial and intracranial hemodynamic alterations occur with internal carotid artery and vertebral artery blunt cervical vascular injuries and can be quantified in the acute injury phase by transcranial Doppler indices. Further study is required to elucidate cerebral flow changes resulting from a single blunt cervical vascular injury, which may guide future management to preserve cerebral perfusion after trauma.

A novel decision tree approach based on transcranial Doppler sonography to screen for blunt cervical vascular injuries.

OBJECTIVES: Early detection and treatment of blunt cervical vascular injuries prevent adverse neurologic sequelae. Current screening criteria can miss up to 22% of these injuries. The study objective was to investigate bedside transcranial Doppler sonography for detecting blunt cervical vascular injuries in trauma patients using a novel decision tree approach. METHODS: This prospective pilot study was conducted at a level I trauma center. Patients undergoing computed tomographic angiography for suspected blunt cervical vascular injuries were studied with transcranial Doppler sonography. Extracranial and intracranial vasculatures were examined with a portable power M-mode transcranial Doppler unit. The middle cerebral artery mean flow velocity, pulsatility index, and their asymmetries were used to quantify flow patterns and develop an injury decision tree screening protocol. Student t tests validated associations between injuries and transcranial Doppler predictive measures. RESULTS: We evaluated 27 trauma patients with 13 injuries. Single vertebral artery injuries were most common (38.5%), followed by single internal carotid artery injuries (30%). Compared to patients without injuries, mean flow velocity asymmetry was higher for single internal carotid artery (P = .003) and single vertebral artery (P = .004) injuries. Similarly, pulsatility index asymmetry was higher in single internal carotid artery (P = .015) and single vertebral artery (P = .042) injuries, whereas the lowest pulsatility index was elevated for bilateral vertebral artery injuries (P = .006). The decision tree yielded 92% specificity, 93% sensitivity, and 93% correct classifications. CONCLUSIONS: In this pilot feasibility study, transcranial Doppler measures were significantly associated with the blunt cervical vascular injury status, suggesting that transcranial Doppler sonography might be a viable bedside screening tool for trauma. Patient-specific hemodynamic information from transcranial Doppler assessment has the potential to alter patient care pathways to improve outcomes.

The utility of procalcitonin in critically ill trauma patients.

BACKGROUND: Procalcitonin (PCT), the prohormone of calcitonin, has an early and highly specific increase in response to systemic bacterial infection. The objectives of this study were to determine the natural history of PCT for patients with critical illness and trauma, the utility of PCT as a marker of sepsis versus systemic inflammatory response syndrome (SIRS), and the association of PCT level with mortality. METHODS: PCT assays were done on eligible patients with trauma admitted to the trauma intensive care unit (ICU) of a Level I trauma center from June 2009 to June 2010, at hours 0, 6, 12, 24, and daily until discharge from ICU or death. Patients were retrospectively diagnosed with SIRS or sepsis by researchers blinded to PCT results. RESULTS: A total of 856 PCT levels from 102 patients were analyzed, with mean age of 49 years, 63% male, 89% blunt trauma, mean Injury Severity Score of 21, and hospital mortality of 13%. PCT concentration for patients with sepsis, SIRS, and neither were evaluated. Mean PCT levels were higher for patients with sepsis versus SIRS (p < 0.0001). Patients with a PCT concentration of 5 ng/mL or higher had an increased mortality when compared with those with a PCT of less than 5 ng/mL in a univariate analysis (odds ratio, 3.65; 95% confidence interval, 1.03-12.9; p = 0.04). In a multivariate logistic analysis, PCT was found to be the only significant predictor for sepsis (odds ratio, 2.37; 95% confidence interval,1.23-4.61, p = 0.01). CONCLUSION: PCT levels are significantly higher in ICU patients with trauma and sepsis and may help differentiate sepsis from SIRS in critical illness. An elevated PCT level was associated with increased mortality.

Differences in management and mortality with a bronchoalveolar lavage-based diagnostic protocol for ventilator-associated pneumonia.

BACKGROUND: Directed antibiotic therapy based on accurate bacteriology is critical to ventilator-associated pneumonia (VAP) treatment. Bronchoalveolar lavage (BAL) has been reported to be more accurate than endotracheal sputum aspirate (ESA) in VAP diagnosis. Our objective was to determine the frequency with which BAL results differ from ESA cultures and the outcomes of VAP with a BAL-based VAP protocol. METHODS: Prospectively collected microbiologic data on all trauma patients with VAP from 2007 through 2009 were reviewed. Per protocol, a positive ESA prompts a BAL and initiation of broad empiric antibiotics with de-escalation based on BAL results. Patients diagnosed with VAP by the protocol were compared with those diagnosed outside of the protocol using univariate and multivariate linear regression analysis. Concordance of ESA and BAL results was evaluated, and cause of death was determined. RESULTS: Of 137 patients with VAP, 96 were diagnosed by the protocol (protocol group) and had 102 pairs of cultures. Twenty-six patients (27%) with 28 pairs of cultures (27.4%) had discordant results. Of discordant pairs, 17 (61%) showed bacteria of a different Gram's stain. Methicillin-sensitive Staphylococcus aureus was the most common causative organism. Mortality was lower in the protocol group (6.3%) than the nonprotocol group (22%, p = 0.014) and mechanically ventilated patients without VAP (24%, p = 0.35) but with comparable Injury Severity Score (ISS). VAP-attributable mortality in the protocol group was 1%. CONCLUSIONS: Use of a BAL-based diagnostic protocol affects management of trauma patients with VAP by improving identification of causative microorganisms and is associated with low overall mortality and VAP-attributable mortality.

Age: is it all in the head? Factors influencing mortality in elderly patients with head injuries.

BACKGROUND: Elderly patients, an increasing segment of the population, who sustain traumatic brain injury (TBI) are known to have worse outcomes, including higher mortality. This objective of this study was to examine the Crash Injury Research Engineering Network and to determine at what age motor vehicle crash fatalities from head injuries increased. METHODS: The Crash Injury Research Engineering Network database was queried from 1996 to 2009. Study inclusion criteria were adult vehicle occupants with TBI, with an Abbreviated Injury Scale score ≥2. The age at which mortality increased was calculated. Patients younger and older than this cutoff age were compared to determine differences in crash characteristics. The determined cutoff age was compared with one found in a larger, population-based database. RESULTS: There were 915 patients who met the study criteria. An increase in mortality was seen at age 60 years despite no difference in Injury Severity Score and a decrease in crash severity. Patients ≤60 years were more likely to have alcohol involved, to be in a rollover crash, and had higher crash speeds. Comparing the element of the crash attributed to the head injury, the patients >60 years were more likely to have struck the airbag, door, and seat. An analysis of the larger database revealed an increase in mortality at age 70 years. CONCLUSIONS: There was a higher mortality secondary to head injuries in those older than 60 years involved in motor vehicle crashes. Improved safety measures in vehicle design may decrease the number of head injuries seen in the older population.

Injury and side impact air bag deployment in near and far sided motor vehicle crashes, United States, 2000-2005.

BACKGROUND: Side impact crashes, the most lethal type, account for 26% of all motor vehicle crashes in the United States. The purpose of this study is to delineate side impact airbag (SIAB) deployment rates, injury rates, and analyze crash factors associated with SIAB deployment and occupant injury. METHODS: All passenger vehicles equipped with SIABs that were involved in a side impact crash were identified from the National Automotive Sampling System database. Crashes with multiple impacts, ejections, unbelted drivers or rollovers were excluded from the study. The outcome variables of interest were SIAB deployment and driver injury. SIAB deployment was compared in similar crashes to analyze the impact on driver's injury severity score. Other crash factors were also examined to analyze what role they play in SIAB deployment rates and injury rates, such as plane of contact, striking object and Delta-V. RESULTS: The data set for this study contained 247 drivers in near and far side crashes in vehicles with installed SIABs. Overall SIAB deployment was 43% in side impact crashes. A significant factor associated with both the SIAB deployment rate and the driver's injury rate was increased Delta-V. CONCLUSIONS: SIABs do not deploy consistently in crashes with a high Delta-V or with a lateral primary direction of force and a front plane of contact. In these two scenarios, further research is warranted on SIAB deployments. With SIAB deployment, it appears drivers are able to sustain a higher Delta-V impact without serious injury.