Faculty Bibliography

BACKGROUND: Computed tomography pulmonary angiography (CTA) is the gold standard for diagnosing pulmonary embolism (PE) but involves radiation and iodinated contrast exposure. Of orthopedic patients evaluated for PE, a minority have a positive CTA study. Herein, we evaluate end tidal carbon dioxide (ETCO2) as a method to identify patients at low risk for PE and may not require a CTA. We hypothesize that ETCO2 will be useful for predicting the absence of PE in postoperative orthopedic patients. METHODS: In this prospective study, all patients older than 18 years who were admitted for orthopedic surgery and who had a CTA performed for PE were eligible. These patients underwent an ETCO2 measurement. Patients were determined to have PE if they had a positive PE-protocol CT. RESULTS: Between May 2014 and April 2015, 121 patients met the inclusion criteria for the study. Of these patients, 84 had a negative CTA examination, 25 had a positive examination, and 12 had a nondiagnostic examination. We found a statistically significant difference (P = .03) when comparing the average ETCO2 values for the positive and negative CTA groups. An ETCO2 cutoff value of 43 mm Hg was 100% sensitive with a negative predictive value of 100% for absence of PE on CTA. CONCLUSION: This study demonstrates a significant difference in ETCO2 measurements between postoperative orthopedic patients with and without CTA-detected PE. A cutoff value of >43 mm Hg may be useful in excluding patients from undergoing CTA.

Hemostasis is a major concern during the perioperative period. Changes in platelet aggregation and coagulation factors may contribute to the delicate balance between thrombosis and bleeding. We sought to better understand perioperative hemostasis by investigating the changes in platelet aggregation and coagulation factors during the perioperative period. We performed a prospective cohort analysis of 70 subjects undergoing non-emergent orthopedic surgery of the knee (n = 28), hip (n = 35), or spine (n = 7) between August 2011 and November 2011. Plasma was collected preoperatively (T1), 1-h intraoperatively (T2), 1-h (T3), 24-h (T4) and 48-h (T5) postoperatively. Platelet function testing was performed using whole blood impedance aggregometry. Coagulation assays were performed for factor VII, factor VIII, von Willebrand Factor (vWF), and fibrinogen. Of the 70 patients, mean age was 64.1 +/- 9.8 years, 61 % were female, and 74 % were Caucasian. Platelet activity decreased until 1 h postoperatively and then significantly increased above baseline at 24- and 48-h postoperatively. Compared to baseline, coagulation factors decreased intraoperatively. Factor VII activity continued to decrease, while FVIII, vWF, and fibrinogen all increased above baseline postoperatively. The results of our study indicate significant changes in platelet activity and coagulation factors during the perioperative period. Both platelet activity and markers of coagulation decrease during the intraoperative period and then some increase postoperatively. These changes may contribute to the hypercoagulabity and/or bleeding risk that occurs in the perioperative period. Future prospective studies aimed at correlating hemostatic changes with perioperative outcomes are warranted.

BACKGROUND: In 2012 the World Health Organization reported 8.7 million new cases of Tuberculosis worldwide, causing 1.4 million deaths (1). Despite modern drug therapy, this disease continues to present in novel ways and mimic other diseases causing misdiagnosis. AIM: We report this case to educate on the reason to suspect atypical Tuberculosis presentation, even if a common disease is diagnosed, when Tuberculosis remains in the differential. We also demonstrate that with globalization and patient moving between countries, that these presentations can occur in locations, where such atypical manifestations are very uncommon. CASE: We report on a 48 year old man with one month of malaise, fever, productive cough, night sweats, chills, pleuritic chest pain, weight loss and progressive non-painful swelling on his thorax. Initial diagnoses of interstitial pneumonia and a thoracic subcutaneous abscess were made. Needle drainage was attempted, with thick purulent material returned. When the sternum was not struck with the needle, a thoracic computed tomography scan was performed. A milliary pattern was noted in the lungs, with a large abscess present anteriorly, completely obliterating the manubrium, approaching the aorta with distant lesions. Subsequent analysis showed the material to be pan-sensitive M. Tuberculosis. CONCLUSION: The issue that this case raises is that when tuberculosi is in the differential, even common diseases may in fact be atypical manifestations of tuberculosis. In addition, when a shallow surgical procedure is going to be performed on the thoracic soft tissues, particularly when tuberculosis is suspected, imaging of the thorax should be obtained.