Is observation for traumatic hemothorax safe?

BACKGROUND: Eastern Association for the Surgery of Trauma guidelines suggest tube thoracostomy (TT) be considered for all traumatic hemothoraces. However, previous research has suggested that some traumatic hemothoraces may be observed safely. We sought to (1) determine the safety of selective observation for traumatic hemothorax and (2) identify predictors of failed observation. METHODS: All patients with traumatic hemothorax from 2000 to 2014 at a Level I trauma center were identified and categorized by size as small (<300 cc) or large (≥300 cc) based on chest computed tomography (CT) scan measurements. Patients with no CT or with TT placement before CT were excluded. Patients were categorized into four intervention groups: (i) early TT (<24 hours after CT), (ii) failed observation (TT ≥24 hours after CT), (iii) successful observation (no TT), and (iv) inevaluable due to early mortality (no TT but died within 7 days). Univariate analyses compared outcomes between groups. Multivariate analyses identified independent predictors of failed observation. RESULTS: Three hundred forty patients met the inclusion criteria. 156 (46%) patients received early TT. Of the 184 patients that were initially observed, 121 (66%) were successfully observed, 53 (29%) failed observation, and 10 (5%) were inevaluable due to early mortality. Most of the successfully observed hemothoraces were small (119/121, 98%). Four independent predictors of failed observation were identified: older age, fewer ventilation-free days, large hemothorax, concurrent pneumothorax. Patients, who received TT were more likely than non-TT patients to receive tissue plasminogen activator, develop an empyema, have fewer hospital-free days, and are discharged to rehabilitation rather than home. When compared to early TT, failed observation was associated with a higher likelihood of discharge to rehabilitation but no difference in mortality, hospital-free days, or rate of empyema. CONCLUSION: Initial observation in select patients is safe and may result in better outcomes. The identified predictors of failed observation can help in clinical decision making regarding the need for TT in patients with traumatic hemothorax. LEVEL OF EVIDENCE: Therapeutic/care management, level IV.

Stress myocardial blood flow correlates with ventricular function and synchrony better than myocardial perfusion reserve: A Nitrogen-13 ammonia PET study.

BACKGROUND: Cardiac PET quantifies stress myocardial blood flow (MBF) and perfusion reserve (MPR), while ECG-gated datasets can measure components of ventricular function simultaneously. Stress MBF seems to outperform MPR in the detection of significant CAD. However, it is uncertain which perfusion measurement is more related to ventricular function. We hypothesized that stress MBF correlates with ventricular function better than MPR in patients studied for suspected myocardial ischemia. METHODS: We studied 248 patients referred to a rest and adenosine-stress Nitrogen-13 ammonia PET. We performed a multivariate analysis using systolic function (left ventricular ejection fraction, LVEF), diastolic function (mean filling rate in diastole, MFR/3), and synchrony (Entropy) as the outcome variables, and stress MBF, MPR, and relevant covariates as the predictors. Secondarily, we repeated the analysis for the subgroup of patients with and without a previous myocardial infarction (MI). RESULTS: 166 male and 82 female patients (mean age 63 ± 11 and 67 ± 11 year, respectively) were included. 60% of the patients presented hypertension, 57% dyslipidemia, 21% type 2 diabetes mellitus, 45% smoking, and 34.7% a previous MI. Mean stress MBF was 1.99 ± 0.75 mL/g/min, MPR = 2.55 ± 0.89, LVEF = 61.6 ± 15%, MFR/3 = 1.12 ± 0.38 EDV/s, and Entropy = 45.6 ± 11.3%. There was a significant correlation between stress MBF (P < .001) and ventricular function. This was stronger than the one for MPR (P = .063). Sex, age, diabetes, and extent of previous MI were also significant predictors. Results were similar for the analyses of the 2 subgroups. CONCLUSION: Stress MBF is better correlated with ventricular function than MPR, as evaluated by Nitrogen-13 ammonia PET, independently from other relevant cardiovascular risk factors and clinical covariates. This relationship between coronary vasodilatory capacity and ventricular function is sustained across groups with and without a previous MI.