Association of biliary distention with a diagnosis of acute cholecystitis

BACKGROUND

Gallbladder distention has been described in radiology literature but its value on point-of-care ultrasound (PoCUS) performed by emergency physicians is unclear. We sought to determine the test characteristics of gallbladder distention on PoCUS for cholecystitis (acute or chronic), and secondarily whether distention was associated with an obstructing stone-in-neck (SIN), acute cholecystitis on subsequent pathology report, and longer cholecystectomy operative times.

METHODS

This was a dual-site retrospective cohort study of all Emergency Department (ED) patients that underwent diagnostic biliary PoCUS and were subsequently admitted from 11/1/2020 to 10/31/2022. Patients with pregnancy, liver failure, ascites, hepatobiliary cancer, prior cholecystectomy, or known cholecystitis were excluded. Gallbladder distention was defined as a width ≥4 cm or a length ≥10 cm. Saved ultrasound images were reviewed by three independent reviewers who obtained measurements during the review. Test characteristics, Cohen's kappa (κ), and strength of association between distention and our variables (acute cholecystitis on pathology report and SIN on PoCUS) were calculated using a Chi Square analysis, where intervention (cholecystectomy, percutaneous cholecystostomy, or intravenous antibiotics) was used as the reference standard for AC. A one-tail two sample t-test was calculated for mean operative times.

RESULTS

Of 280 admitted patients who underwent ED biliary PoCUS, 53 were excluded, and 227 were analyzed. Of the 227 patients, 113 (49.8%) had cholecystitis according to our reference standard, and 68 (30.0%) had distention on PoCUS: 32 distended by both width and length, 16 distended by width alone, and 20 distended by length alone. Agreement between investigators was substantial for width (κ 0.630) and length (κ 0.676). Distention was 85.09% (95% CI 77.20-91.07%) specific and 45.1% (95% CI 35.8-54.8%) sensitive for cholecystitis. There was an association between distention and SIN; odds ratio (OR) 2.76 (95% CI 1.54-4.97). Distention of both length and width was associated with acute over chronic cholecystitis; OR 4.32 (95% CI 1.42-13.14). Among patients with acute cholecystitis, mean operative times were 114 min in patients with distention and 89 min in patients without distention (p = 0.03).

CONCLUSION

Gallbladder distention on PoCUS was specific for cholecystitis (acute or chronic), and associated with SIN, acute cholecystitis on subsequent pathology report, and longer cholecystectomy operative times. Measurement of gallbladder dimensions as part of the assessment of cholecystitis may be advantageous.

Point-of-care ultrasound associated with shorter length of stay than computed tomography for renal colic

BACKGROUND

Despite similar diagnostic effectiveness for renal colic, computed tomography (CT) is more resource intensive than point-of-care ultrasound (PoCUS). We sought to compare Emergency Department (ED) length of stay (LOS) among patients with renal colic according to imaging modality utilized. We secondarily compared rates of infection, return ED visits, missed significant pathology, and urologic intervention.

METHODS

This was a 12-month (1/1/22-12/31/22) multi-site retrospective cohort study of all patients diagnosed with renal colic who presented to the ED on days when at least one patient had a billable renal PoCUS examination performed. Patients with a history of genitourinary malignancy, pregnancy, renal transplant, hemodialysis, single kidney, prior visit for renal colic in the previous 30 days, or an incomplete workup were excluded. Median ED LOS was compared using a Wilcoxon rank sum test, and the 95% confidence limits for the difference between medians was calculated. Secondary outcomes were compared using a Fisher's Exact test.

RESULTS

Of 415 patients screened, 325 were included for analysis: 150 had CT alone, 80 had PoCUS alone, 54 had PoCUS plus CT, and 41 had neither. Median LOS for PoCUS alone was 75.0 (95% CI 39.3-110.7) minutes shorter than CT alone (231.5 vs. 307.0 min, p < 0.0001). Similar rates of infection, return visits, and missed pathology occurred across all groups (p > 0.10). Urologic interventions were higher in the PoCUS plus CT (25.9%) group compared to CT alone (7.3%), PoCUS alone (2.5%), and neither (7.3%), p < 0.0001.

CONCLUSION

Among patients with renal colic, PoCUS was associated with shorter ED LOS compared to CT, without differences in infection rates, return visits, or missed pathology. Patients with PoCUS plus CT had a higher rate of urologic interventions, suggesting PoCUS may have a role in identifying patients who would most benefit from CT.

Radiology Imaging Adds Time and Diagnostic Uncertainty when Point of Care Ultrasound Demonstrates Cholecystitis

BACKGROUND

Point of care ultrasound (POCUS) is specific for acute cholecystitis (AC), but surgeons request radiology imaging (RI) prior to admitting patients with POCUS-diagnosed AC.

OBJECTIVES

We sought to determine the test characteristics of POCUS for AC when performed and billed by credentialed emergency physicians (EPs), the accuracy rate of RI when performed after POCUS, and the time added when RI is requested after POCUS demonstrates AC.

METHODS

We performed a dual-site retrospective cohort study of admitted adult ED patients who had received biliary POCUS from November 1, 2020 to April 30, 2022. Patients with previously diagnosed AC, liver failure, ascites, hepatobiliary cancer, or cholecystectomy were excluded. Descriptive statistics and 95% confidence intervals for point estimates were calculated. Medians were compared using a Wilcoxon signed-rank test. Test characteristics of POCUS for AC were calculated using inpatient intervention for AC as the reference standard.

RESULTS

Of 473 screened patients, 143 were included for analysis: 80 (56%) had AC according to our reference standard. POCUS was positive for AC in 46 patients: 44 true positives and two false positives, yielding a positive likelihood ratio of 17.3 (95%CI 4.4-69.0) for AC. The accuracy rate of RI after positive POCUS for AC was 39.0%. Median time from ED arrival to POCUS and ED arrival to RI were 115 (IQR 64, 207) and 313.5 (IQR 224, 541) minutes, respectively; p < 0.01.

CONCLUSION

RI after positive POCUS performed by credentialed EPs takes additional time and may increase diagnostic uncertainty.

Best Practices for Point of Care Ultrasound: An Interdisciplinary Expert Consensus

Despite the growing use of point of care ultrasound (POCUS) in contemporary medical practice and the existence of clinical guidelines addressing its specific applications, there remains a lack of standardization and agreement on optimal practices for several areas of POCUS use. The Society of Point of Care Ultrasound (SPOCUS) formed a working group in 2022 to establish a set of recommended best practices for POCUS, applicable to clinicians regardless of their training, specialty, resource setting, or scope of practice. Using a three-round modified Delphi process, a multi-disciplinary panel of 22 POCUS experts based in the United States reached consensus on 57 statements in domains including: (1) The definition and clinical role of POCUS; (2) Training pathways; (3) Credentialing; (4) Cleaning and maintenance of POCUS devices; (5) Consent and education; (6) Security, storage, and sharing of POCUS studies; (7) Uploading, archiving, and reviewing POCUS studies; and (8) Documenting POCUS studies. The consensus statements are provided here. While not intended to establish a standard of care or supersede more targeted guidelines, this document may serve as a useful baseline to guide clinicians, leaders, and systems considering initiation or enhancement of POCUS programs.

Prevalence and implications of perinephric fluid on renal point-of-care ultrasound in the emergency department

BACKGROUND

Point-of-care ultrasound (PoCUS) is commonly utilized in the setting of renal colic. The presence of perinephric fluid may be an overlooked finding associated with ureteral obstruction. Our aims were to determine the prevalence of perinephric fluid on emergency physician-performed PoCUS and to determine whether perinephric fluid was associated with stone size or urologic intervention.

METHODS

This was a 12-month cross-sectional study at an academic emergency department (ED) that took place from January 1, 2022, to December 31, 2022. All adult ED patients ≥18 years of age who had a renal PoCUS examination performed were included. Patients with missing or inadequate PoCUS images were excluded. Investigators blinded to PoCUS images and interpretations performed chart review for demographic data and outcome variables, while separate investigators blinded to clinical data reviewed PoCUS images to assess for perinephric fluid and hydronephrosis. A chi-square analysis was used to determine significance of association between perinephric fluid and outcome variables (stone size, urologic intervention).

RESULTS

There were 442 patients screened; 18 were excluded due to inadequate images and 4 were repeat visits of which only the initial visit was analyzed. Of the remaining 420 patients included, the prevalence of perinephric fluid was 6.2% (n = 26). Most patients (23/26) with perinephric fluid had final diagnoses consistent with ureterolithiasis. Hydronephrosis was present in 115 of the 420 patients (27.4%) and of these, 22 (19.1%) had perinephric fluid which was significantly associated with a need for urologic intervention; odds ratio (OR) 10.38 (95% CI 2.70-39.85), p < 0.01. Among the 67 patients with confirmed ureterolithiasis on computed tomography, perinephric fluid was associated with stone size ≥5 mm; OR 4.00 (95% CI 1.01-15.85), p = 0.04.

CONCLUSION

The prevalence of perinephric fluid on emergency physician-performed renal PoCUS was 6.2% of all studies and 19.1% of patients with hydronephrosis. In the setting of ureterolithiasis, perinephric fluid was associated with larger stone size and need for urologic intervention.

Prevalence of Phantom Scanning in Cardiac Arrest and Trauma Resuscitations: The Scary Truth

Background: The prevalence of phantom scanning, or point of care ultrasound (POCUS) performed without saving images, has not been well studied. Phantom scanning can negatively affect patient care, reduce billed revenue, and can increase medicolegal liability. We sought to quantify and compare the prevalence of phantom scanning among emergency department (ED) cardiac arrests and trauma resuscitations. Methods: This was a single center, retrospective cohort study from July 1, 2019, to July 1, 2021, of all occurrences of POCUS examination documented on the resuscitation run sheet during cardiac arrest and trauma resuscitations. Two investigators reviewed the run sheets to screen for POCUS documentation. Instances where documentation was present were matched with saved images in the picture archiving and communication system. Instances where documentation was present but no images could be located were considered phantom scans. A two-tailed student's t test was utilized to compare the phantom scanning rate between cardiac arrest and trauma resuscitations. Results: A total of 1,862 patients were included in the study period, with 329 cardiac arrests and 401 trauma resuscitations having run sheet documentation of POCUS performance. The phantom scanning rate in cardiac arrests and trauma resuscitations was 70.5% (232/329) and 86.5% (347/401), respectively (p < 0.001). Conclusion: Phantom scanning is common in both cardiac arrests and trauma resuscitations in the ED at our institution, but is significantly higher in trauma resuscitations. Further research is needed to assess causes and develop potential solutions to reduce the high prevalence of phantom scanning.

Minutes matter: Time it takes to perform point-of-care ultrasound

Background

While point-of-care ultrasound (PoCUS) is a safe, versatile tool that can improve patient care, the perceived time investment needed to incorporate PoCUS into clinical care is cited as a barrier to performance. We sought to determine the time it takes to perform a PoCUS examination and whether this time was influenced by training level and prior ultrasound experience.

Methods

This was a retrospective study looking at time stamps of all emergency medicine (EM) provider-performed PoCUS examinations during clinical shifts from August 10, 2019, to June 7, 2022, at a suburban academic emergency department that is the site for a 3-year EM residency. Our workflow is order-based; when PoCUS is ordered, that patient's information populates the ultrasound machine worklist. Selecting the patient's name from the worklist generates a time-stamped patient information page (PIP). We defined the PIP time stamp as the start of the PoCUS examination. The duration of one PoCUS examination was defined as the time of the last image acquired minus the time of the PIP. General estimating equations were used to estimate differences between training level and between prior scan status using an exchangeable correlation and Tukey adjusted pairwise comparisons. A two-tailed chi-square analysis was used for comparing accuracy according to training level.

Results

Of 4187 PoCUS examinations abstracted, 2144 met study criteria. The median (IQR) time spent per examination was 6.0 (3-9) min. First-year residents took the longest to perform PoCUS among all providers (p < 0.0001). Residents with fewer than 250 prior scans took longer than residents with 501-800 (p = 0.0002) and >800 (p = 0.0013). Resident accuracy was not significantly different according to training level.

Conclusions

Overall median time to perform PoCUS was 6.0 min. EM residents became more efficient in performing PoCUS as they advanced from first- to third-year, without compromising accuracy.

Point-of-care ultrasound may expedite diagnosis and revascularization of occult occlusive myocardial infarction

BACKGROUND

Electrocardiographically occult occlusive myocardial infarction (OOMI), defined as coronary artery occlusion requiring revascularization without ST-segment elevation on electrocardiogram (ECG), is associated with delayed diagnosis resulting in higher morbidity. Left ventricular (LV) wall motion abnormalities (WMA) appreciated on echocardiography can expedite OOMI diagnosis. We sought to determine whether point-of-care ultrasound (PoCUS) demonstrating WMA expedites revascularization time when performed on emergency department patients being evaluated for OOMI.

METHODS

This was a single-site retrospective cohort study over a 38-month period. All admitted adult ED patients ≥35 years of age evaluated by the emergency physician with PoCUS for LV function, an ECG, and a standard troponin I biomarker assay were included. Patients with ST-segment elevation myocardial infarction (STEMI), prior LV dysfunction, fever ≥100.4 °F, or hypotension were excluded. A structured chart abstraction was performed for relevant demographic and clinical characteristics.

RESULTS

We screened 1561 ED patients who underwent cardiac PoCUS for eligibility: 874 met exclusion criteria, 453 were discharged, and 234 were included in the analysis. Twenty-three patients had coronary interventions, of which 14 had WMA. PoCUS was performed 36 min (IQR -9-68) before troponin resulted (n = 234) and 39 min (IQR -23-96) before the first troponin elevation (n = 85). Twenty of the 23 patients diagnosed with OOMI had elevated troponins prior to catheterization with time from PoCUS to first troponin elevation of 43 min (IQR 9-263). Of these patients, 11 had WMA identified on PoCUS, and the WMA was appreciated 47 min (IQR 26-255) prior to troponin elevation. The time from ED arrival to revascularization was 673 min (IQR 251-2158); 432 min (IQR 209-1300) among patients with WMA (n = 14) compared with 2158 min (IQR 552-3390) for those without WMA (n = 9).

CONCLUSION

Cardiac PoCUS may identify OOMI earlier than standard evaluation and may expedite definitive management.

Massive Ovarian Cyst Mimics Constipation

BACKGROUND

Abdominal pain and constipation are common presenting symptoms of pediatric patients presenting to the emergency department. Sometimes these symptoms are related to uncomplicated constipation from stool burden, and other cases may be secondary to more serious pathologies, including obstruction from intra- or extra-intestinal compression. Point-of-care ultrasound (PoCUS) can be helpful in discerning the etiology for this undifferentiated symptomatology.

CASE REPORT

A 14-year-old girl presented with 3 days of constipation and abdominal pain. This was similar to previous symptoms that resolved with laxatives. This time, however, her symptoms were associated with one episode of vomiting. PoCUS expanded a narrow differential with the discovery of a large ovarian cyst. This finding helped to expedite her transfer to a pediatric hospital for definitive treatment in the operating room. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Constipation is one of the leading reasons pediatric patients present to the ED with abdominal pain. PoCUS can detect uncommon causes of constipation, especially pathologies associated with large volumes of fluid, such as a large ovarian cyst, bladder outlet obstruction, or small bowel obstruction.

Feasibility of pneumoperitoneum diagnosis using point-of-care ultrasound: a pilot study using a fresh cadaver model

AIMS

To assess the accuracy of point-of-care ultrasound (PoCUS) in the hands of two trained and blinded emergency physicians (EPs) in detecting very small amounts of free intraperitoneal air injected intra-abdominally, using a fresh human cadaver model.

MATERIAL AND METHODS

Fifteen cadavers were injected on 3 occasions with predefined quantities of free intraperitoneal air ranging from 0-10 mL. Seven cadavers were injected in the mid-epigastrium (ME), while 8 were injected in the left lower quadrant (LLQ). Each cadaver was scanned after each of the 3 injections by 2 trained and blinded EPs, resulting in 45 scans per sonographer. Scans were performed using previously validated and standardized techniques. All scans were recorded, time-stamped and labeled. For each scan the sonographers indicated "yes" or "no" to whether pneumoperitoneum was detected. A chi square analysis was performed to determine the sensitivity and specificity of PoCUS utilized by each sonographer of pneumoperitoneum based on the location and volume of air injected.

RESULTS

Free air (0.25-10 mL) injected into the ME was successfully diagnosed in 36/42 instances (86% sensitivity), but only detected in 10/36 instances when injected into the LLQ (28% sensitivity). Both EPs detected all air injections of ≥2 mL into the ME.

CONCLUSION

Detection of free air originating from the midepigastric region may become a future PoCUS indication for adequately trained EPs.

Effectiveness of Near-Peer Versus Faculty Point-of-Care Ultrasound Instruction to Third-Year Medical Students

Background: Incorporation of point-of-care ultrasound (POCUS) in undergraduate medical education (UME) is expanding; however, its effective implementation is impeded by a lack of trained faculty. Recruitment of near-peer (NP) instructors is a potential solution, but there are concerns surrounding NP teaching effectiveness compared to faculty instruction. While some institutions have assessed supplemental NP instruction, or NP-taught sessions with strict faculty supervision, few if any have compared effectiveness of NP POCUS instruction alone to faculty instruction through a multi-dimensional assessment. The aim of this study was to compare the effectiveness of near-peer (NP) instruction to faculty instruction at an undergraduate medical education clinical POCUS session for third-year medical students. Methods: This was a randomized controlled trial where third-year medical students were assigned to one of two groups for a 90-minute POCUS session: NP instruction or faculty instruction. A pre- and post-session multiple-choice test and a post-session objective structured clinical examination (OSCE) were administered to assess conceptual and hands-on clinical POCUS knowledge gained. Students' perceptions of the instructors and session were evaluated using a Likert scale. Results: Seventy-three students (66% of the class) participated; 36 taught by faculty and 37 by NP instructors. Both groups showed a significant score increase from pre-test to post-test (p =0.002); however, there was no significant difference between groups in post-test (p=0.27) nor OSCE scores (p=0.20). Student perceptions of instructor competency were not statistically significant. Conclusions: NP instructors were as effective at teaching clinical POCUS to third-year medical students as faculty instructors at our institution.

Ultrasound-guided spinal accessory nerve block for intractable trapezius pain: A case series

Myofascial pain affects about 10% of the United States population, often involves the trapezius muscle, and can be difficult to manage using conventional analgesic medications in the Emergency Department (ED). The use of ultrasound-guided nerve blocks performed by emergency physicians is well-documented, but this is the first report describing the technique and effectiveness of an ultrasound-guided spinal accessory nerve block for acutely treating trapezius myofascial pain in the ED setting. In this case series of three patients with intractable trapezius pain, the ultrasound-guided spinal accessory nerve block proved feasible and offered substantial therapeutic benefit.

Acute unilateral hydronephrosis in the setting of hemorrhagic cystitis

Acute flank pain associated with hematuria and unilateral hydronephrosis is a classic presentation for an obstructing ureteral stone. However, in the setting of hemorrhagic cystitis, blood can acutely obstruct the distal ureter and infrequently result in hydronephrosis. We present a case of an adult female patient with hemorrhagic cystitis who presented with acute right flank pain associated with unilateral hydronephrosis and perinephric fluid on point-of-care ultrasound (PoCUS) in the absence of renal or ureteral abnormality on CT scan hours earlier. Her symptoms resolved, urine cultures showed no growth, and her outpatient follow-up was unremarkable. We suspect given the acute onset of right obstructive uropathy, an unremarkable CT just hours earlier, and the brief nature of her symptoms, that blood obstructed her distal UVJ leading to acute and transient obstructive uropathy.

Point-of-Care Ultrasound Assists Diagnosis of Spontaneously Passed Common Bile Duct Stone

BACKGROUND

Choledocholithiasis complicates approximately 10% of gallstone disease. Spontaneous stone migration out of the common bile duct (CBD) may occur in as many as 20% of choledocholithiasis cases. A decrease in CBD caliber occurs in the setting of spontaneous stone passage, but to our knowledge, this finding has not been appreciated using point-of-care ultrasound (POCUS) in the emergency medicine setting.

CASE REPORT

A 49-year-old woman presented to our Emergency Department (ED) with a complaint of epigastric pain radiating to the left shoulder. On examination she was found to have epigastric tenderness to palpation, but no guarding or rebound. POCUS demonstrated a dilated common bile duct, and her liver function tests were abnormally high. She was admitted to Medicine with concern for choledocholithiasis and plan for endoscopic retrograde cholangiopancreatography (ERCP), but her pain had resolved shortly after ED arrival. A repeat ultrasound examination demonstrated a normal-caliber common bile duct approximately 3 h after the initial scan. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Choledocholithiasis often requires admission and invasive testing. Using POCUS in conjunction with liver function tests and patient assessments may obviate a need for ERCP.