In a paper recently published in Chest, Llamas-Álvarez et al have undertaken a systematic review and meta-analysis of lung ultrasound for the diagnosis of pneumonia in adults. Studies examining patients over the age of 18 with either community acquired or nosocomial pneumonia were included. The reference standard was plain radiography, CT scanning or both.
The authors identified 16 studies involving 2359 patients. Six studies were performed in an ICU setting, 7 in emergency departments, with remainder in wards or a combined ward /ED. The reported sensitivities and specificities of the individual studies ranged from 0.57 - 1.00 and 0.54-0.99 respectively.
The meta-analysis showed a pooled sensitivity of 80-90% and specificity of 70-90%, with an area under the SROC curve of 0.93, leading the authors to conclude that "bedside lung ultrasonography has excellent accuracy for the diagnosis of pneumonia in adults".
Llamas-Alvarez AM, Tenza-Lozano EM, Latour-Perez J. Accuracy of Lung Ultrasonography in the Diagnosis of Pneumonia in Adults: Systematic Review and Meta-Analysis. Chest. 2017 Feb;151(2):374-382.
Supraclavicular brachial plexus blocks provide anaesthesia for the upper limb below the shoulder, excluding the medial upper arm. There are a number of great resources to guide you through learning the block. The addition of ultrasound has greatly improved the safety of this approach compared.
If you need to revise the anatomy of the brachial plexus have a look at this page from Medscape
Medscape -brachial plexus anatomy
NYSORA have a fantastic page detailing the anatomy, ultrasound anatomy and injection technique. They include a useful flow chart to guide you through the process of identifying the brachial plexus.
NYSORA - ultrasound guided brachial plexus block
Sonoguide provide a brief outline of the technique and potential complications. Flash is required to view the video clips
Sonoguide - supraclavicular brachial plexus block
Neuraxiom's page provide the usual high quality illustrations which make understanding the technique and the ultrasound images incredibly simple
Neuraxiom - The Supraclavicular Brachial Plexus Block
Sonosite have produed a number of videos detailing the technique. The '3D - how to' video makes it particularly easy to understand what you will see in your ultrasound image
Ultrasound-Guided Popliteal Sciatic Block - NYSORA
The usual high quality from NYSORA with a very useful cross sectional anatomy image.
Popliteal block - Neuraxiom
Another fantastic resource from Neuraxiom. Flash is required to use view some of the images.
Popliteal block - Cambridge Anaesthetics
This resources again describe the technique but shows how to perform the block in a supine patient by using a chair on the bed to elevate the limb to be blocked - just don't tell the infection control nurses!
The SonoSite video below shows the block being performed with simultaneous 3D anatomy animations
The issue of safety in ultrasound is often overlooked by novice sonographers. The British Medical Ultrasound Society has published a number of statements on safety in ultrasound.
BMUS - safety statements
The detailed guidance provides recommended maximum scanning times based on the type of examination being performed and the thermal and mechanical indices.
Of note for those providing training in ultrasound is safety guidance for using volunteers for training
The Management of Safety when using Volunteers and Patients for Practical Training
Whatever you are doing you should always remember the ALARA principle - As Low As Reasonably Achievable.
If you need a quick revision of thermal and mechanical indices, Radiopedia provides a useful brief overview.
Pablo Blanco and Giovanni Volpicelli have written a very useful guide to errors in point of care ultrasound, showing how they may occur and proving practical tips to avoid getting caught out.
They cover the following areas:
If you are performing PoCUS this paper provides a useful guide to reflect on your current practice.
Blanco P, Volpicelli G. Common pitfalls in point-of-care ultrasound: a practical guide for emergency and critical care physicians. Crit Ultrasound J. 2016 Dec;8(1):15
Following on from our recent post about the study by Barbic et al showing the utility of PoCUS in soft tissue infection here are a couple of resources to show you how the ultrasound features of abscess and soft tissue infection.
Soft tissue ultrasound - Sonoguide
Ultrasound of Skin and Soft Tissue Infections- Joseph Minardi
Below are links to resources on this site to help you get up speed before the course or to review what you have been taught after.
Central venous access
Peripheral venous access
Philips Point of Care echo pocket guide
Barbic et al have published a systematic review and meta-analysis examining the diagnostic accuracy of PoCUS in diagnosing abscesses in emergency department patients with skin and soft tissue infections. Comparison was made with a reference standard of abscess diagnosis based upon CT, findings on incision and draining or final clinical diagnosis at follow up. 8 studies ( 3 adult and 5 paediatric) totalling 747 patients were included in the analysis.
The diagnostic performance was found to be as follows:
Sensitivity- 96.2% (95% CI 91.1% to 98.4%)
Specificity- 82.9% (95% CI 60.4% to 93.9%)
Positive likelihood ratio- 5.6 (95% CI 2.2 to 14.6)
Negative likelihood ratio- 0.05 (95% CI 0.02 to 0.11).
A pre-planned subgroup analysis showed similar performance in paediatric patients.
The full article can be found here:
In patients presenting to the emergency department with skin and soft tissue infections what is the diagnostic accuracy of point-of-care ultrasonography for the diagnosis of abscess compared to the current standard of care? A systematic review and meta-analysis
A great text-based overivew of biliary ultrasound from SonoGuide covering both normal anatomy and pathology. However, the web page needs Flash so choose your device accordingly
Biliary ultrasound - Sonoguide