Study design: Systematic review.
Setting: Published and unpublished randomized, controlled trials performed worldwide.
Synopsis: The research examined in this study was composed of randomized, controlled trials that investigated CIN prevention and included IV sodium bicarbonate in one of the treatment groups. Nine published and 15 unpublished trials were selected for a total of 3,563 patients studied. The overall pooled relative risk of CIN in patients treated with IV sodium bicarbonate compared with normal saline was 0.62 (95% CI, 0.45-0.86), though the strength of this evidence was questioned.
Significant heterogeneity across studies was found (I2=49.1%; P=0.004), partially related to substantially greater treatment effect in published (RR 0.43, 95% CI, 0.25-0.75) versus unpublished (RR 0.78, 95% CI, 0.52-1.17) studies. Publication bias was confirmed statistically. Among the published studies, greater treatment effect favoring bicarbonate over saline tended to be reported in those published before 2008, had fewer patients (<200) and events (<15), had measured events within 48 hours, and were studies of lower quality.
No effects regarding the risk of heart failure, the need for dialysis, or mortality were found, though the studies were not specifically designed to investigate those clinical outcomes. Larger studies are needed to better assess these questions.
Bottom line: IV sodium bicarbonate for CIN prevention in high-risk patients could be less effective than previous reports have suggested.
Citation: Zoungas S, Ninomiya T, Huxley R, et al. Systematic review: sodium bicarbonate treatment regimens for the prevention of contrast-induced nephropathy. Ann Intern Med. 2009;151(9):631-638.
Incidental Findings More Frequent than PE in Chest CT Angiograms
Clinical question: What is the prevalence of incidental findings on chest-computed tomographic angiograms (CTAs) ordered by an ED to evaluate for pulmonary embolism (PE)?
Background: CTAs commonly are ordered by ED physicians to assess for PE. While CTAs might yield findings to support an alternate diagnosis to PE, incidental findings might be found that often require further radiographic or clinical followup. The workup of these incidental findings can be burdensome and low-yield.
Study design: Retrospective chart review.
Setting: Single, academic, tertiary-care hospital in North Carolina.
Synopsis: All patients who underwent CTA evaluation for PE in the ED over two enrollment periods were selected; radiographic findings were compiled and their medical records reviewed. Fifty-five of 589 CTAs (9%) were positive for PE. New incidental findings requiring radiographic or clinical followup were found in 141 cases (24%).
Overall, pulmonary nodules were most common, requiring followup in 73 (13%) cases. Adenopathy requiring followup was seen in 51 cases (9%), and new masses requiring followup were found in 12 cases (2%). Findings to support alternate diagnoses for shortness of breath, hypoxemia, or tachycardia were found in 195 patients (33%), most commonly pleural effusion (19%) and infiltrates (11%). Other incidental findings that required less-urgent clinical attention were common with 615 total findings, most frequently nonmalignant bone findings in 144 cases (24%), mild dependent atelectasis in 137 cases (23%), and emphysema in 69 cases (12%).