Evidence & Independent Review
Published performance stated exactly as studied, cited inline — alongside what independent reviewers said about it, and the limitations they raised.
How we label evidence
Every protocol carries one of these labels. They are not interchangeable: a described technique is not a comparison study, and neither is a case series. The label states the strongest claim that protocol’s own citations support.
- Published method
- Technique described, not clinical-outcome validation
- Prospective comparison
- Agreement/performance study
- Retrospective implementation
- Feasibility in clinical use
- Case series
- Descriptive evidence without comparator
- Educational framework
- Derived application, not directly validated
- Investigational
- Research use only
- In development
- Not ready for clinical teaching
Published studies and case series
Original research on EASy — the papers that collected patient data. The methods and protocol papers, reviews, and book chapters are on publications.
Retrospective exploratory case series — EASy-PDA
Bughrara N, Tso MS, Weigand ME, et al. Integrating Rapid Cardiopulmonary and Gastric Ultrasound for Emergency Airway Management in Critically Ill Patients: A Case Series of Resident-Performed Echocardiographic Assessment Using Subcostal-Only-View in Physiologically Difficult Airway. Crit Care Explor 2025;7(11):e1340.
30 patients needing emergency airway management outside the operating room, scanned by trained anesthesiology residents before induction. Mean examination time 2.40 minutes; findings were sufficient to inform management in 26 of 30 (86.7%), prompting an emergent pericardial window in one patient and gastric decompression in two. The subcostal four-chamber view could not be obtained in one patient because of severe abdominal pain. A feasibility study: it was not designed to show whether EASy-PDA reduces peri-intubation complications or improves outcomes, and does not establish that it does.
doi:10.1097/CCE.0000000000001340Implementation study
Bughrara N, Neilson MR, Jones S, Workman L, Chopra A, Pustavoitau A. Is 1 day of focused training in echocardiographic assessment using subxiphoid-only (EASy) examination enough? A tertiary hospital response to COVID-19. Crit Care Explor 2024;6(3):e1038.
doi:10.1097/CCE.0000000000001038Prospective observational study
Bughrara N, Renew JR, Alabre K, et al. Comparison of qualitative information obtained with the echocardiographic assessment using subcostal-only view and focused transthoracic echocardiography examinations. Can J Anaesth 2022;69(2):196–204.
doi:10.1007/s12630-021-02152-6Case series
Bughrara N, Herrick SL, Leimer E, Sirigaddi K, Roberts K, Pustavoitau A. Focused cardiac ultrasound and the periresuscitative period: a case series of resident-performed echocardiographic assessment using subcostal-only view in advanced life support. A A Pract 2020;14(10):e01278.
doi:10.1213/XAA.0000000000001278
Independent Commentary
Two independent groups assessed the published EASy work in Can J Anaesth. These are their voices, not ours.
The editorialists commend the work for refining “the minimum competency standards of the operator” and the scope of point-of-care ultrasound that still yields clinically valuable information — while reducing the time the scan takes.
An independent group from Catania, London, and Cambridge judged the study capable of laying the foundations for a shift in basic critical care echocardiography training, and suggested “EASY will become the first approach novices learn.”
Performance
Fast enough to repeat
Prospective comparison — mean examination time, novice sonographers
The shorter examination time is intended to make serial reassessment more feasible as physiology changes — a design rationale, not a measured repeat-exam rate.
Published novice performance averaged approximately 4–4.3 minutes. Through deliberate practice and supervised repetition, the EASy competency pathway targets reliable completion in under 3 minutes while obtaining adequate-quality images.
Fiorini & Basmaji, Can J Anaesth 2022;69(2):187–191
Compared against focused transthoracic echocardiography using parasternal, apical, and subcostal windows, subcostal-only assessment showed almost perfect agreement for pericardial effusion (Gwet's AC1 0.98), interventricular septal motion (0.92), and RV contractility (0.84), and substantial agreement for RV size (0.70), LV size (0.73), and LV contractility (0.73). (Can J Anaesth 2022)
Limitations
The window fails in a meaningful minority. Of the 102 patients in the comparison study, 82 yielded good or adequate subcostal images and were analyzed; in the other 20 the images were poor quality or could not be obtained. The editorialists note that setting those aside may overestimate the benefit of the assessment, and conclude that this view cannot be relied on alone for a significant number of patients.
The conclusion is conditional. When subcostal images could be obtained, the qualitative information was sufficiently accurate compared with full focused transthoracic echocardiography.
Interpretation in that study was performed by experts, who may require fewer data points than novices to act — which is why the EASy pathway keeps interpretation supervised.
Agreement was measured in aggregate. Gwet's coefficient does not show whether disagreements clustered on ruling pathology in or ruling it out.
EASy is not an accreditation pathway. Independent commentary states that in isolation it is unlikely to be sufficient for accreditation in critical care echocardiography.
Future validation
Both commentaries call for external validation, and one recommends full adherence to the PRICES reporting standard for critical care echocardiography research. Prospective multicentre evaluation is the next step, and EASy's development follows that roadmap.
The central question is external: can clinicians trained at institutions the developers do not lead reproduce the results? Each rung below is answered before the next is claimed, so that agreement on images is never presented as evidence about patients.
- 1
Acquisition
Can independently trained learners obtain adequate images, judged on the 12-point quality scale?
- 2
Interpretation
Do they correctly identify the individual findings in each view?
- 3
Phenotype agreement
Do independent readers assign the same cluster and phenotype to the same examination?
- 4
Clinical integration
Does the phenotype lead to an appropriate next question or action, and when does it prompt escalation?
- 5
Outcomes
Does EASy-guided assessment change process measures or patient outcomes? Not yet studied — no outcome claim is made.
Looking for the full bibliography? View all publications.