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348 Diagnosing Acute Cholecystitis with Bedside Ultrasonography
Research Forum Abstracts
Figure. The anatomic and sonographic landmarks for the ultrasound-guided interscalene brachial plexus nerve block. A. Optimal ultrasound image of the brachial plexus at the interscalene groove: (1) Sternocleidomastoid (SCM). (2) anterior scalene muscle, (3) middle scalene muscle, (4) Carotid artery and internal jugular vein, (5) interscalene groove with C5, C6, C7 cervical roots visualized, (6) in-plane needle approach. B. Schematic diagram of relevant interscalene brachial plexus anatomy. C. Patient positioning with overlay showing underlying relevant anatomy. Methods: Three emergency physicians including an attending emergency physician with greater than 100 ultrasound-guided blocks experience, an emergency physician ultrasound fellow, and a resident emergency physician were prospectively evaluated. The resident and fellow received a standardized training module developed by the attending emergency physician. A randomized cohort of ED patients was generated using bed numbers to prevent a biased selection of patients. Time to set up and identification of external anatomical landmarks was recorded. Times to acquisition of an optimal ultrasound image and accuracy of identification of six anatomical structures (internal carotid, sternocleidomastoid, anterior scalene muscle, middle scalene muscle, and the C5, C6 and C7 roots of the brachial plexus) as well the ideal in-plane needling tract were recorded. Subjects were asked to rate their confidence in structure identification for each scan (Table) Results: Twenty patients were enrolled for a total of 40 ultrasound examinations. Seventy percent were female; the mean body mass index (BMI) was 31, ranging from 15 to 53. The average set-up time was 1 minute and 30 seconds. Ultrasonographic landmarks were successfully identified in all patients by the attending emergency physician. Mean scanning times were 25 seconds and 1 minute, 32 seconds for the attending and resident/fellow respectively. There were 2 instances where the resident or fellow failed to correctly identify the interscalene brachial plexus; these were both middleaged patients who were severely (BMI>35) or very severely obese (BMI >40) (Figure). Conclusions: In this randomly selected cohort of ED patients, both attending and resident-level providers were able to quickly and accurately identify the important anatomic and ultrasonographic structures needed to perform an ultrasound-guided interscalene brachial plexus block. Severely obese patients may pose a challenge to providers early in training. More study is needed to better understand how emergency physicians can acquire and maintain competency performing ultrasound-guided regional anesthesia.
348
Diagnosing Acute Cholecystitis with Bedside Ultrasonography
Rifenburg R, Litchke C, Chan S/Resurrection Medical Center, Chicago, IL
Study Objectives: Emergency bedside gallbladder ultrasonography (EBUS) is able to identify abnormalities in acute cholecystitis (AC) as accurately as radiologyperformed gallbladder ultrasonography (GUS). But what abnormalities most closely correlate with AC? If emergency physicians are able to promptly diagnose AC with EBUS, treatment could be rendered more efficiently. Methods: We conducted a retrospective analysis of all EBGU performed from April 2008 to March 2014. Emergency physician assessed for gallstones (GS), sludge (S), anterior wall thickening (AWT), sonographic Murphy’s sign (SMS), common bile duct dilation
Volume 64, no. 4s : October 2014
(CBD), gallbladder distention (D), and pericholecystic fluid (PCF). EBGU findings were reviewed by the ultrasound director and compared with radiology findings. All study patients had a cholecystectomy performed with subsequent pathologic diagnosis. The pathologic results were subsequently compared with EBGU findings. Differences between acute and chronic cholecystitis were tested using Pearson Chi-square and likelihood ratios with 95% confidence intervals. All P values are two-tailed and statistical significance set at .05. Results: Between 2008 and 2014, 302 cases of suspected cholecystitis were abstracted from patients with EBGU, subsequent cholecystectomy, and pathology reports. Radiology GUS was performed on 241 (79.8%) patients. Abdominal CT scan was performed on 99 (32.8%) patients. There were 102 cases (33.8%) of AC (54 of which had both acute and chronic cholecystitis) and 188 cases (62.2%) of chronic cholecystitis. Final pathology showed gallstones in 267 (88.4%) patients. EBGU had gallstone accuracy rate of 84.4% (kappa¼.353) while radiology GUS had accuracy of 92.5% (kappa¼.584). SMS and CBD were not predictive of AC while S, AWT, and D were all predictive of AC. On EBGU, the positive likelihood ratio for S was 1.30 (95% CI: 1.01, 1.65) versus 1.65 (95% CI: 1.19, 2.22) for radiology GUS. Likelihood ratio for AWT was 1.90 (95% CI: 1.22, 2.94) on EBGU versus 2.03 (95% CI: 1.39, 2.90) for radiology GUS. Likelihood ratio for D was 2.90 (95% CI: 1.07, 8.09) on EBGU versus 1.68 (95% CI: 1.18, 2.35) for radiology GUS. When evaluating combinations of EBGU findings S, AWT, and D together gave a likelihood ratio of 7.73 (95% CI: .794, 173.1) on EBGU versus 11.4 (95% CI: 2.50, 74.3) for radiology GUS. Conclusion: Sonographic Murphy’s sign and common bile duct dilation were not predictive of acute cholecystitis while sludge, anterior wall thickening, and distention were predictive. The combination of all three had the highest likelihood ratio for AC. Our results confirm prior studies indicating that emergency physician are adept at identifying (versus diagnosing) gallbladder abnormalities with similar results as radiology GUS. The gallbladder abnormalities which significantly correlated with acute cholecystitis had similar likelihood ratios regardless of emergency physician or radiology performed ultrasound.
349
Assessing the Need for Dedicated Inferior Vena Cava Ultrasound Education in Emergency Medicine Residents
Dulani T, Bajaj T, Ayala S, Giorgetti R, Balk A, Chiricolo G/New York Methodist Hospital, Brooklyn, NY
Background: Ultrasound of the inferior vena cava (IVC) is used as a surrogate to estimate intravascular volume status as an alternative to invasive central venous pressure monitoring. Visualizing the IVC is routinely taught as a standard view on the focused
Annals of Emergency Medicine S123
Figure. The anatomic and sonographic landmarks for the ultrasound-guided interscalene brachial plexus nerve block. A. Optimal ultrasound image of the brachial plexus at the interscalene groove: (1) Sternocleidomastoid (SCM). (2) anterior scalene muscle, (3) middle scalene muscle, (4) Carotid artery and internal jugular vein, (5) interscalene groove with C5, C6, C7 cervical roots visualized, (6) in-plane needle approach. B. Schematic diagram of relevant interscalene brachial plexus anatomy. C. Patient positioning with overlay showing underlying relevant anatomy. Methods: Three emergency physicians including an attending emergency physician with greater than 100 ultrasound-guided blocks experience, an emergency physician ultrasound fellow, and a resident emergency physician were prospectively evaluated. The resident and fellow received a standardized training module developed by the attending emergency physician. A randomized cohort of ED patients was generated using bed numbers to prevent a biased selection of patients. Time to set up and identification of external anatomical landmarks was recorded. Times to acquisition of an optimal ultrasound image and accuracy of identification of six anatomical structures (internal carotid, sternocleidomastoid, anterior scalene muscle, middle scalene muscle, and the C5, C6 and C7 roots of the brachial plexus) as well the ideal in-plane needling tract were recorded. Subjects were asked to rate their confidence in structure identification for each scan (Table) Results: Twenty patients were enrolled for a total of 40 ultrasound examinations. Seventy percent were female; the mean body mass index (BMI) was 31, ranging from 15 to 53. The average set-up time was 1 minute and 30 seconds. Ultrasonographic landmarks were successfully identified in all patients by the attending emergency physician. Mean scanning times were 25 seconds and 1 minute, 32 seconds for the attending and resident/fellow respectively. There were 2 instances where the resident or fellow failed to correctly identify the interscalene brachial plexus; these were both middleaged patients who were severely (BMI>35) or very severely obese (BMI >40) (Figure). Conclusions: In this randomly selected cohort of ED patients, both attending and resident-level providers were able to quickly and accurately identify the important anatomic and ultrasonographic structures needed to perform an ultrasound-guided interscalene brachial plexus block. Severely obese patients may pose a challenge to providers early in training. More study is needed to better understand how emergency physicians can acquire and maintain competency performing ultrasound-guided regional anesthesia.
348
Diagnosing Acute Cholecystitis with Bedside Ultrasonography
Rifenburg R, Litchke C, Chan S/Resurrection Medical Center, Chicago, IL
Study Objectives: Emergency bedside gallbladder ultrasonography (EBUS) is able to identify abnormalities in acute cholecystitis (AC) as accurately as radiologyperformed gallbladder ultrasonography (GUS). But what abnormalities most closely correlate with AC? If emergency physicians are able to promptly diagnose AC with EBUS, treatment could be rendered more efficiently. Methods: We conducted a retrospective analysis of all EBGU performed from April 2008 to March 2014. Emergency physician assessed for gallstones (GS), sludge (S), anterior wall thickening (AWT), sonographic Murphy’s sign (SMS), common bile duct dilation
Volume 64, no. 4s : October 2014
(CBD), gallbladder distention (D), and pericholecystic fluid (PCF). EBGU findings were reviewed by the ultrasound director and compared with radiology findings. All study patients had a cholecystectomy performed with subsequent pathologic diagnosis. The pathologic results were subsequently compared with EBGU findings. Differences between acute and chronic cholecystitis were tested using Pearson Chi-square and likelihood ratios with 95% confidence intervals. All P values are two-tailed and statistical significance set at .05. Results: Between 2008 and 2014, 302 cases of suspected cholecystitis were abstracted from patients with EBGU, subsequent cholecystectomy, and pathology reports. Radiology GUS was performed on 241 (79.8%) patients. Abdominal CT scan was performed on 99 (32.8%) patients. There were 102 cases (33.8%) of AC (54 of which had both acute and chronic cholecystitis) and 188 cases (62.2%) of chronic cholecystitis. Final pathology showed gallstones in 267 (88.4%) patients. EBGU had gallstone accuracy rate of 84.4% (kappa¼.353) while radiology GUS had accuracy of 92.5% (kappa¼.584). SMS and CBD were not predictive of AC while S, AWT, and D were all predictive of AC. On EBGU, the positive likelihood ratio for S was 1.30 (95% CI: 1.01, 1.65) versus 1.65 (95% CI: 1.19, 2.22) for radiology GUS. Likelihood ratio for AWT was 1.90 (95% CI: 1.22, 2.94) on EBGU versus 2.03 (95% CI: 1.39, 2.90) for radiology GUS. Likelihood ratio for D was 2.90 (95% CI: 1.07, 8.09) on EBGU versus 1.68 (95% CI: 1.18, 2.35) for radiology GUS. When evaluating combinations of EBGU findings S, AWT, and D together gave a likelihood ratio of 7.73 (95% CI: .794, 173.1) on EBGU versus 11.4 (95% CI: 2.50, 74.3) for radiology GUS. Conclusion: Sonographic Murphy’s sign and common bile duct dilation were not predictive of acute cholecystitis while sludge, anterior wall thickening, and distention were predictive. The combination of all three had the highest likelihood ratio for AC. Our results confirm prior studies indicating that emergency physician are adept at identifying (versus diagnosing) gallbladder abnormalities with similar results as radiology GUS. The gallbladder abnormalities which significantly correlated with acute cholecystitis had similar likelihood ratios regardless of emergency physician or radiology performed ultrasound.
349
Assessing the Need for Dedicated Inferior Vena Cava Ultrasound Education in Emergency Medicine Residents
Dulani T, Bajaj T, Ayala S, Giorgetti R, Balk A, Chiricolo G/New York Methodist Hospital, Brooklyn, NY
Background: Ultrasound of the inferior vena cava (IVC) is used as a surrogate to estimate intravascular volume status as an alternative to invasive central venous pressure monitoring. Visualizing the IVC is routinely taught as a standard view on the focused
Annals of Emergency Medicine S123