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Study objective We evaluate the frequency of emergency department (ED) ultrasonographic probe contamination and the bacterial species involved and evaluate probe cleaning and disinfection methods. Methods This was a 3-part observational cross-sectional study. Surveillance cultures were taken of linear and curvilinear probes on 3 ultrasonographic machines between patient encounters. Cultures of uncovered probes were taken immediately after scanning of skin and soft tissue infections. After experimental probe contamination with methicillin-resistant Staphylococcus aureus (MRSA), we assessed 3-step disinfection by sequential cleaning with a dry towel, saline solution–moistened towel, and quaternary ammonia germicidal wipe and 1-step disinfection by germicidal wipe alone. Cultures were obtained by applying the probe to a blood agar plate. Results In part 1, of 164 surveillance cultures obtained from 6 probes on 29 sampling days during 11 months, 111 (67%; 95% confidence interval [CI] 60% to 74%) grew normal skin flora or environmental flora, 52 had no growth (32%; 95% CI 25% to 39%), and 2 (1.2%; 95% CI 0.3% to 4.3%) grew a clinically important pathogen. In part 2, 14 of 20 (70%; 95% CI 48% to 85%) cultures taken after skin and soft tissue infection scanning produced heavy growth of a clinically important pathogen, including 13 S aureus (5 MRSA). In part 3, cleaning with a dry and moist towel reduced but did not eliminate MRSA. The germicidal wipe step resulted in no growth in 15 of 15 (100%; 95% CI 80% to 100%) cultures in 3-step disinfection and in 9 of 10 (90%; 95% CI 60% to 98%) when used alone. Conclusion Skin and environmental flora are commonly present on ultrasonographic probes between patient encounters in our ED; however, clinically important pathogens are uncommon. S aureus (including MRSA) frequently contaminates uncovered probes during skin and soft tissue infection scanning, but in an experimental model, MRSA appears to be reliably removed by a quaternary ammonia germicidal wipe if the probe is partially cleaned first.

Study objective Among adult emergency department (ED) patients undergoing central venous catheterization, we determine whether a greater than or equal to 50% decrease in inferior vena cava diameter is associated with a central venous pressure of less than 8 mm Hg. Methods Adult patients undergoing central venous catheterization were enrolled in a prospective, observational study. Inferior vena cava inspiratory and expiratory diameters were measured by 2-dimensional bedside ultrasonography. The caval index was calculated as the relative decrease in inferior vena cava diameter during 1 respiratory cycle. The correlation of central venous pressure and caval index was calculated. The sensitivity, specificity, and positive and negative predictive values of a caval index greater than or equal to 50% that was associated with a central venous pressure less than 8 mm Hg were estimated. Results Of 73 patients, the median age was 63 years and 60% were women. Mean time and fluid administered from ultrasonographic measurement to central venous pressure determination were 6.5 minutes and 45 mL, respectively. Of the 73 participants, 32% had a central venous pressure less than 8 mm Hg. The correlation between caval index and central venous pressure was –0.74 (95% confidence interval [CI] –0.82 to –0.63). The sensitivity of caval index greater than or equal to 50% to predict a central venous pressure less than 8 mm Hg was 91% (95% CI 71% to 99%), the specificity was 94% (95% CI 84% to 99%), the positive predictive value was 87% (95% CI 66% to 97%), and the negative predictive value was 96% (95% CI 86% to 99%). Conclusion Bedside ultrasonographic measurement of caval index greater than or equal to 50% is strongly associated with a low central venous pressure. Bedside measurements of caval index could be a useful noninvasive tool to determine central venous pressure during the initial evaluation of the ED patient.

INTRODUCTION Acute pain management for patients sustaining injuries in natural disasters and complex emergencies should be a priority for medical providers. Although there are minimal data examining the modalities and effectiveness of pain control in disaster settings, what data exist reveal practices that would be considered grossly inadequate in a typical emergency department (ED) setting. Ultrasound-guided nerve blocks performed by emergency physicians who have undergone targeted training have the potential to positively affect pain control and safety for patients with traumatic injuries in disaster settings. Femoral, popliteal, forearm, and interscalene blocks have been used safely and successfully in the ED setting for fracture reduction and splinting, incision and drainage, and complex wound care, procedures frequently required in disaster settings. The inherent difficulties of disaster settings do raise challenges to documentation, sterile technique, and monitoring for adverse effects such as local anesthetic systemic toxicity (LAST) that will require further investigation. Emergency physicians, already trained in procedural ultrasound skills and frequently required to perform extremity procedures in daily practice, are positioned to rapidly gain training and proficiency with nerve blocks. Once mastered, ultrasound-guided nerve blocks have the potential to greatly improve pain control in disaster settings, as well as in the general practice of emergency medicine. Ultrasound-guided nerve blocks are being increasingly introduced into emergency medicine practice to provide pain control for patients presenting with traumatic injuries and those undergoing painful procedures. The challenges to pain control in disaster and resource-limited settings make ultrasound-guided nerve block particularly applicable in these settings as a central component of a multimodal approach to pain management. Emergency ultrasoundguided nerve blocks have proven utility in combat and disaster settings, using the deposition of local anesthetics around peripheral nerves to induce a reversible loss of sensation with minimal central nervous system and cardiovascular adverse effects. Emergency ultrasound-guided nerve blocks differ from the traditional practice of perioperative regional anesthesia, however, in having a primary goal of acute pain reduction in the setting of n