Right Ventricular "Bubble Time" to Identify Patients With Right Ventricular Dysfunction.

STUDY OBJECTIVE: We propose a novel method of evaluating right ventricular (RV) dysfunction in the emergency department (ED) using RV "bubble time"-the duration of time bubbles from a saline solution flush are visualized in the RV on echocardiography. The objective was to identify the optimal cutoff value for RV bubble time that differentiates patients with RV dysfunction and report on its diagnostic test characteristics. METHODS: This prospective diagnostic accuracy study enrolled a convenience sample of hemodynamically stable patients in the ED. A sonographer administered a 10-mL saline solution flush into the patient's intravenous catheter, performed a bedside echocardiogram, and measured RV bubble time. Subsequently, the patient underwent a comprehensive cardiologist-interpreted echocardiogram within 36 hours, which served as the gold standard. Patients with RV strain or enlargement of the latter found on an echocardiogram were considered to have RV dysfunction. Bubble time was evaluated by a second provider, blinded to the initial results, who reviewed the ultrasound clips. The primary outcome measure was the optimal cutoff value of RV bubble time that identifies patients with and without RV dysfunction. RESULTS: Of 196 patients, median age was 67 year, and half were women, with 69 (35.2%) having RV dysfunction. Median RV bubble time among patients with RV dysfunction was 62 seconds (interquartile range [IQR]: 52, 93) compared with 21 seconds (IQR: 12, 32) among patients without (P<.0001). The optimal cutoff value of RV bubble time for identifying patients with RV dysfunction was 40 or more seconds, with a sensitivity of 0.97 (95% CI 0.93 to 1.00) and specificity of 0.87 (95% CI 0.82 to 0.93). CONCLUSION: In patients in the ED, an RV bubble time of 40 or more seconds had high sensitivity in identifying patients with RV dysfunction, whereas an RV bubble time of less than 40 seconds had good specificity in identifying patients without RV dysfunction. These findings warrant further investigation in undifferentiated patient populations and by emergency physicians without advanced ultrasound training.

Ultrasound Identification of Retrobulbar Hematomas by Emergency Physicians in a Cadaveric Model.

INTRODUCTION: Retrobulbar hemorrhage (RBH) is a rare complication of facial trauma that can lead to dangerous orbital compartment pressures and must be rapidly recognized to prevent permanent vision loss. Point-of-care ultrasound (POCUS) offers a rapid modality for evaluating a wide variety of ocular pathologies, and prior case reports demonstrate the ability of clinicians to recognize RBH using ultrasound. This study aimed to assess the ability of clinicians at various stages of training to identify a RBH using POCUS in a cadaveric model. Clinicians also were assessed for self-reported comfort using ultrasound for ocular pathology before and after the study. METHODS: Participants included 17 physicians who evaluated 10 eyes (from five cadavers) that were independently randomized to have either a modeled RBH or no hemorrhage. Participants' final diagnosis of each eye was recorded (RBH present or not), and participants also completed pre- and post-activity surveys. RESULTS: The overall sensitivity and specificity to correctly diagnose retrobulbar fluid was 87% and 88%, respectively. Sensitivity and specificity were higher after excluding clinicians in their early phase of training. Additionally, self-reported comfort level with ocular ultrasound was significantly improved by this activity. CONCLUSION: Emergency physicians at a variety of training levels can correctly identify a cadaveric model of retrobulbar hemorrhage. Use of this cadaveric model can improve exposure of clinicians to the appearance of a rare but vision-threatening ocular pathology such as RBH.

Gonococcal Tenosynovitis Diagnosed with the Aid of Emergency Department Bedside Ultrasound.

BACKGROUND: Gonorrhea is the second most common sexually transmitted infection. Disseminated gonococcal infection (DGI) consists of gonococcal infection plus one or more of the triad of arthritis, tenosynovitis, and dermatitis. Diagnosis in the emergency department (ED) must be suspected clinically, as confirmatory tests are often not available. Point-of-care ultrasound (POCUS) can aid in diagnosis and appropriate management by identifying tenosynovitis and excluding arthritis. CASE REPORT: A 26-year-old man with multiple recent sex partners presented to the ED with slowly progressing right wrist pain and swelling over 5 days. His dorsal right wrist was swollen, with slightly decreased range of motion owing to mild pain, and no warmth, tenderness, erythema, or drainage. Multiple hemorrhagic, gray-purple blisters were noted over both hands. Serum white blood cell count was 12 × 103/µL; C-reactive protein was 30.3 mg/L. POCUS of the dorsal right wrist found no joint effusion; the extensor tendon sheath contained a large anechoic space with clear separation of the extensor tendons, suggesting a tendon sheath effusion/tenosynovitis. DGI was suspected, without septic arthritis. The patient was admitted and treated with ceftriaxone and azithromycin. Gonococcus grew from blood cultures and pharyngeal swabs. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: DGI must be suspected clinically, as confirmatory tests are often not available in the ED. Not all patients present with arthritis, tenosynovitis, and dermatitis. It is often difficult to differentiate tenosynovitis from arthritis. POCUS can aid in diagnosis by identifying tenosynovitis (vs. arthritis or simple soft-tissue swelling), allowing timely appropriate DGI diagnosis and management, and, importantly, averting unnecessary arthrocentesis.

Ultrasound-Guided Femoral Nerve Block to Facilitate the Closed Reduction of a Dislocated Hip Prosthesis.

Prosthetic hip dislocation is a common but unfortunate complication in patients who have undergone total hip arthroplasty. Successful closed reduction in the emergency department leads to a reduced length of stay and rate of hospitalization.1,2 The use of regional anesthesia by femoral nerve block represents a novel approach for controlling pain in patients with hip pathologies.3 Ultrasound-guided approaches have been used with great success for controlling pain in patients with hip fractures.4,5 Here we report the case of a 90-year-old male who presented with a dislocated hip prosthesis, which was subsequently corrected with closed reduction following delivery of regional anesthesia to the femoral nerve under ultrasound guidance. To our knowledge, this represents the first reported use of an ultrasound-guided femoral nerve block to facilitate closed reduction of a dislocated prosthetic hip, and highlights a novel approach that avoids the use of procedural sedation in an elderly patient.

Neuropilin2 regulates the guidance of post-crossing spinal commissural axons in a subtype-specific manner.

BACKGROUND: Spinal commissural axons represent a model system for deciphering the molecular logic that regulates the guidance of midline-crossing axons in the developing central nervous system (CNS). Whether the same or specific sets of guidance signals control the navigation of molecularly distinct subtypes of these axons remains an open and largely unexplored question. Although it is well established that post-crossing commissural axons alter their responsiveness to midline-associated guidance cues, our understanding of the repulsive mechanisms that drive the post-crossing segments of these axons away from the midline and whether the underlying guidance systems operate in a commissural axon subtype-specific manner, remains fragmentary at best. RESULTS: Here, we utilize axonally targeted transgenic reporter mice to visualize genetically distinct dorsal interneuron (dI)1 and dI4 commissural axons and show that the repulsive class 3 semaphorin (Sema3) guidance receptor Neuropilin 2 (Npn2), is selectively expressed on the dI1 population and is required for the guidance of post-crossing dI1, but not dI4, axons. Consistent with these observations, the midline-associated Npn2 ligands, Sema3F and Sema3B, promote the collapse of dI1, but not dI4, axon-associated growth cones in vitro. We also identify, for the first time, a discrete GABAergic population of ventral commissural neurons/axons in the embryonic mouse spinal cord that expresses Npn2, and show that Npn2 is required for the proper guidance of their post-crossing axons. CONCLUSIONS: Together, our findings indicate that Npn2 is selectively expressed in distinct populations of commissural neurons in both the dorsal and ventral spinal cord, and suggest that Sema3-Npn2 signaling regulates the guidance of post-crossing commissural axons in a population-specific manner.