Here is a quick look at three articles published in the July issue of Annals of Emergency Medicine. Visit www.annemergmed.com to read the full text.

Patient Perceptions of Computed Tomographic Imaging and Their Understanding of Radiation Risk and Exposure

By B. M. Baumann et al.

• What is already known on this topic: Emergency department use of computed tomography (CT) imaging has rapidly increased over the past several years, resulting in substantial radiation exposure to patients.
• What question this study addressed: The authors surveyed 1,168 emergency department patients who presented with abdominal pain to
• assess the patients’ confidence in the medical evaluations they received – which ranged from history and physical (H&P) only to H&P plus laboratory testing and CT imaging – and the patients’ understanding of radiation exposure and of radiation-related cancer risk.
• What this study adds to our knowledge: Patients reported far greater confidence in evaluations that included CT imaging, but they substantially underestimated the amount of radiation involved and the risks of that radiation.
• How is this relevant to clinical practice: These results reinforce the need for increased public education regarding the appropriate use of CT imaging and the risks inherent in such imaging.

Hospital Determinants of Emergency Department Left Without Being Seen Rates

By R. Y. Hsia et al.

• What is already known on this topic: Emergency department left without being seen (LWBS) rates are considered an important indicator of access to care and ED performance.
• What question this study addressed: The variation in LWBS rates and hospital characteristics associated with LWBS rates for all acute care, nonfederal California hospitals in 2007.
• What this study adds to our knowledge: Upon analyzing more than 9 million visits at 262 hospitals, the authors found that reported LWBS rates varied from 0% to 20% (median 2.6%). Emergency departments that serve low-income communities and communities with a high proportion of poorly insured patients had higher rates of patients who left without being seen. Hospital structural characteristics associated with increased LWBS rates included county ownership, trauma center designation, and teaching program affiliation.
• How this is relevant to clinical practice: Emergency departments that are seeking to lower their LWBS rate will need to institute changes that go beyond fine-tuning ED operations.

Accuracy of Noninvasive Multiwave Pulse Oximetry Compared With Carboxyhemoglobin From Blood Gas Analysis in Unselected Emergency Department Patients

By D. Roth et al.

• What is already known on this topic: Multiwave pulse oximetry can noninvasively determine carbon monoxide levels.
• What question this study addressed: This prospective study of 1,578 patients determined the bias and precision of multiwave pulse oximetry using blood gas analysis as the criterion standard.
• What this study adds to our knowledge: Bias and precision seemed acceptable. Negative predictive value at a cutoff of SpCO 6.6% was 100%; however, there were only 17 patients with carbon monoxide poisoning in the cohort.
• How this is relevant to clinical practice: This noninvasive technique could be an effective means for screening at-risk populations for carbon monoxide poisoning. Further assessment in samples with a higher prevalence of carbon monoxide poisoning is required to establish the accuracy of this technology.