Clinical question: How does “triple rule out” (TRO) computed tomographic (CT) angiography compare to other imaging modalities in evaluating coronary and other life-threatening etiologies of chest pain, such as pulmonary embolism (PE) and aortic dissection?
Background: TRO CT angiography is a noninvasive technology that evaluates the coronary arteries, thoracic aorta, and pulmonary vasculature simultaneously. Comparison with other tests in the diagnosis of common clinical conditions is useful information for clinical practice.
Study design: Systematic review and meta-analysis.
Setting: Systematic review of 11 studies (one randomized, 10 observational).
Synopsis: Using an enrolled population of 3,539 patients, TRO CT was compared to other imaging modalities on the basis of image quality, diagnostic accuracy, radiation, and contrast volume. When TRO CT was compared to dedicated CT scans, no significant imaging difference was discovered. TRO CT detected CAD with a sensitivity of 94.3% (95% CI, 89.1% to 97.5%, I2=58.2%) and specificity of 97.4% (95% CI, 96.1% to 98.5%, I2=91.2%).
An insufficient number of patients with PE or aortic dissection were studied to generate diagnostic accuracy for these conditions. TRO CT involved greater radiation exposure and contrast exposure than non-TRO CT.
This study reports high accuracy of TRO CT in the diagnosis of coronary artery disease. Due to the low prevalence of patients with PE or aortic dissection (<1%), the data cannot be extrapolated to these conditions.
Bottom line: Although TRO CT is highly accurate for detecting coronary artery disease, there is insufficient data to recommend its use for the diagnosis of PE or aortic dissection.
Citation: Ayaram D, Bellolio MF, Murad MH, et al. Triple rule-out computed tomographic angiography for chest pain: a diagnostic systematic review and meta-analysis. Acad Emerg Med. 2013;20(9):861-871.
Colloids vs. Crystalloids for Critically Ill Patients Presenting with Hypovolemic Shock
Clinical question: In critically ill patients admitted to the ICU with hypovolemic shock, does the use of colloid for fluid resuscitation, compared with crystalloid, improve mortality?
Background: The current Surviving Sepsis Campaign guidelines recommend crystalloids as the preferred fluid for resuscitation of patients with hypovolemic shock; however, evidence supporting the choice of intravenous colloid vs. crystalloid solutions for management of hypovolemic shock is weak.
Study design: RCT.
Setting: International, multi-center study.
Synopsis: Researchers randomized 2,857 adult patients who were admitted to an ICU and required fluid resuscitation for acute hypovolemia to receive either crystalloids or colloids.
At 28 days, there were 359 deaths (25.4%) in the colloids group vs. 390 deaths (27.0%) in the crystalloids group (P=0.26). At 90 days, there were 434 deaths (30.7%) in the colloids group vs. 493 deaths (34.2%) in the crystalloids group (P=0.03).
Renal replacement therapy was used in 11.0% of the colloids group vs. 12.5% of the crystalloids group (P=0.19). There were more days alive without mechanical ventilation in the colloids group vs. the crystalloids group at seven days (P=0.01) and at 28 days (P=0.01), and there were more days alive without vasopressor therapy in the colloids group vs. the crystalloids group at seven days (P=0.04) and at 28 days (P=0.03).
Major limitations of the study included the use of open-labeled fluids during allocation, so the initial investigators were not blinded to the type of fluid. Moreover, the study compared two therapeutic strategies (colloid vs. crystalloids) rather than two types of molecules.
Bottom line: In ICU patients with hypovolemia requiring resuscitation, the use of colloids vs. crystalloids did not result in a significant difference in 28-day mortality; however, 90-day mortality was lower among patients receiving colloids.
Citation: Annane D, Siami S, Jaber S, et al. Effects of fluid resuscitation with colloids vs crystalloids on mortality of critically ill patients presenting with hypovolemic shock: the CRISTAL randomization trial. JAMA. 2013;310(17):1809-1817.