Faculty Bibliography

BACKGROUND: Penetrating Extremity Trauma (PET) may result in arterial injury, a rare but limb- and life-threatening surgical emergency. Timely, accurate diagnosis is essential for potential intervention in order to prevent significant morbidity. OBJECTIVES: Using a systematic review/meta-analytic approach, we determined the utility of physical examination, Ankle-Brachial Index (ABI), and Ultrasonography (US) in the diagnosis of arterial injury in emergency department (ED) patients who have sustained PET. We applied a test-treatment threshold model to determine which evaluations may obviate CT Angiography (CTA). METHODS: We searched PubMed, Embase, and Scopus from inception to November 2016 for studies of ED patients with PET. We included studies on adult and pediatric subjects. We defined the reference standard to include CTA, catheter angiography, or surgical exploration. When low-risk patients did not undergo the reference standard, trials must have specified that patients were observed for at least 24 hours. We used the Quality Assessment Tool for Diagnostic Accuracy Studies (QUADAS-2) to evaluate bias and applicability of the included studies. We calculated positive and negative likelihood ratios (LR+ and LR-) of physical examination ("hard signs" of vascular injury), US, and ABI. Using established CTA test characteristics (sensitivity = 96.2%, specificity = 99.2%) and applying the Pauker-Kassirer method, we developed a test-treatment threshold model (testing threshold = 0.14%, treatment threshold = 72.9%). RESULTS: We included eight studies (n = 2,161, arterial injury prevalence = 15.5%). Studies had variable quality with most at high risk for partial and double verification bias. Some studies investigated multiple index tests: physical examination (hard signs) in three studies (n = 1,170), ABI in five studies (n = 1,040), and US in four studies (n = 173). Due to high heterogeneity (I2 > 75%) of the results, we could not calculate LR+ or LR- for hard signs or LR+ for ABI. The weighted prevalence of arterial injury for ABI was 14.3% and LR- was 0.59 (95% confidence interval [CI] = 0.48-0.71) resulting in a posttest probability of 9% for arterial injury. Ultrasonography had weighted prevalence of 18.9%, LR+ of 35.4 (95% CI = 8.3-151), and LR- of 0.24 (95% CI = 0.08-0.72); posttest probabilities for arterial injury were 89% and 5% after positive or negative US, respectively. The posttest probability of arterial injury with positive US (89%) exceeded the CTA treatment threshold (72.9%). The posttest probabilities of arterial injury with negative US (5%) and normal ABI (9%) exceeded the CTA testing threshold (0.14%). Normal examination (no hard or soft signs) with normal ABI in combination had LR- of 0.01 (95% CI = 0.0-0.10) resulting in an arterial injury posttest probability of 0%. CONCLUSIONS: In PET patients, positive US may obviate CTA. In patients with a normal examination (no hard or soft signs) and a normal ABI, arterial injury can be ruled out. However, a normal ABI or negative US cannot independently exclude arterial injury. Due to high study heterogeneity, we cannot make recommendations when hard signs are present or absent or when ABI is abnormal. In these situations, one should use clinical judgment to determine the need for further observation, CTA or catheter angiography, or surgical exploration.

BACKGROUND: Serum venous lactate (LAC) levels help guide emergency department (ED) resuscitation of patients with major trauma. Critical LAC level (CLAC, >/=4.0 mmol/L) is associated with increased disease severity and higher mortality in injured patients. The characteristics of injured patients with non-CLAC (NCLAC) (<4.0 mmol/L) and death have not been previously described. OBJECTIVES: (1) To describe the characteristics of patients with venous NCLAC and death from trauma. (2) To assess the correlation of venous NCLAC with time of death. METHODS: A retrospective cohort study at an urban teaching hospital between 9/2011 and 8/2014. Inclusion: All trauma patients (all ages) who presented to the ED with any injury and met all criteria: (1) Venous LAC drawn at the time of arrival that resulted in an NCLAC level; (2) were admitted to the hospital; (3) died during their hospitalization. Exclusion: CLAC. Outcome: Correlation of NCLAC and time of death. Data were extracted from an electronic medical record by trained data abstractors using a standardized protocol. Cross-checks were performed on 10% of data entries and inter-observer agreement was calculated. Data were explored using descriptive statistics and Kaplan-Meier curves were created to define survival estimates. Data are presented as percentages with 95% confidence interval (CI) for proportions and medians with quartiles for continuous variables. Kaplan-Meier curves with differences in time to events based on LAC are used to analyze the data. RESULTS: A total of 60 patients met the inclusion criteria. The median age was 52 years (quartiles: 30, 75) and 73% were male (age range 2-92). The median LAC in the overall cohort was 1.9 mmol/L (quartiles: 1.5, 2.1). Sixteen patients (27%) died during the first 24 h with 5 (31%) due to intracranial hemorrhage. The median survival time was 5.6 days (134.4 h) (95% CI: 2.3-12.6). CONCLUSIONS: In trauma patients with NCLAC who died during the index hospitalization, the median survival time was 5.6 days, approximately one-third of patients died within the first 24 h. These findings indicate that relying on a triage NCLAC level alone may result in underestimating injury severity and subsequent morbidity and mortality.

BACKGROUND: Acute cholecystitis (AC) is a common differential for patients presenting to the emergency department (ED) with abdominal pain. The diagnostic accuracy of history, physical examination, and bedside laboratory tests for AC have not been quantitatively described. OBJECTIVES: We performed a systematic review to determine the utility of history and physical examination (H&P), laboratory studies, and ultrasonography (US) in diagnosing AC in the ED. METHODS: We searched medical literature from January 1965 to March 2016 in PubMed, Embase, and SCOPUS using a strategy derived from the following formulation of our clinical question: patients-ED patients suspected of AC; interventions-H&P, laboratory studies, and US findings commonly used to diagnose AC; comparator-surgical pathology or definitive diagnostic radiologic study confirming AC; and outcome-the operating characteristics of the investigations in diagnosing AC were calculated. Sensitivity, specificity, and likelihood ratios (LRs) were calculated using Meta-DiSc with a random-effects model (95% CI). Study quality and risks for bias were assessed using the Quality Assessment Tool for Diagnostic Accuracy Studies. RESULTS: Separate PubMed, Embase, and SCOPUS searches retrieved studies for H&P (n = 734), laboratory findings (n = 74), and US (n = 492). Three H&P studies met inclusion/exclusion criteria with AC prevalence of 7%-64%. Fever had sensitivity ranging from 31% to 62% and specificity from 37% to 74%; positive LR [LR+] was 0.71-1.24, and negative LR [LR-] was 0.76-1.49. Jaundice sensitivity ranged from 11% to 14%, and specificity from 86% to 99%; LR+ was 0.80-13.81, and LR- was 0.87-1.03. Murphy's sign sensitivity was 62% (range = 53%-71%), and specificity was 96% (range = 95%-97%); LR+ was 15.64 (range = 11.48-21.31), and LR- was 0.40 (range = 0.32-0.50). Right upper quadrant pain had sensitivity ranging from 56% to 93% and specificity of 0% to 96%; LR+ ranged from 0.92 to 14.02, and LR- from 0.46 to 7.86. One laboratory study met criteria with a 26% prevalence of AC. Elevated bilirubin had a sensitivity of 40% (range = 12%-74%) and specificity of 93% (range = 77%-99%); LR+ was 5.80 (range = 1.25-26.99), and LR- was 0.64 (range = 0.39-1.08). Five US studies with a prevalence of AC of between 10% and 46%. US sensitivity was 86% (range = 78%-94%) and specificity was 71% (range = 66%-76%); LR+ was 3.23 (range = 1.74-6.00), and LR- was 0.18 (range = 0.10-0.33). CONCLUSION: Variable disease prevalence, coupled with limited sample sizes, increases the risk of selection bias. Individually, none of these investigations reliably rule out AC. Development of a clinical decision rule to include evaluation of H&P, laboratory data, and US are more likely to achieve a correct diagnosis of AC.

OBJECTIVE: This study describes emergency department (ED) sepsis patients with non-critical serum venous lactate (LAC) levels (LAC <4.0 mmol/L) who suffered in-hospital mortality and examines LAC in relation to survival times. METHODS: An ED based retrospective cohort study accrued September 2010 to August 2014. Inclusion criteria were ED admission, LAC sampling, >2 systemic inflammatory response syndrome criteria with an infectious source (sepsis), and in-hospital mortality. Kaplan-Meier curves were used for survival estimates. An a priori sub-group analysis for patients with repeat LAC within 6 hours of initial sampling was undertaken. The primary outcome was time to in-hospital death evaluated using rank-sum tests and regression models. RESULTS: One hundred ninety-seven patients met inclusion criteria. Pulmonary infections were the most common (44%) and median LAC was 1.9 mmol/L (1.5, 2.5). Thirteen patients (7%) died within 24 hours and 79% by