S Munirama1, K Zealley1, A Schwab2, M Columb3, G A Corner4, R Eisma5, G A McLeod6. 1. Department of Anaesthesia, Ninewells Hospital & Medical School, Dundee, UK. 2. Institute of Medical Physics, Friedrich Alexander University-Erlangen-Nuremberg, Erlangen, Germany. 3. Intensive Care Unit, Wythenshawe Hospital, South Manchester University Hospitals, Manchester, UK. 4. Department of Bioengineering, University of Dundee, Dundee, UK. 5. Centre for Anatomy and Human Identification, University of Dundee, Dundee, UK. 6. Institute of Academic Anaesthesia, Ninewells Hospital & Medical School, Dundee, UK g.a.mcleod@dundee.ac.uk.
Abstract
BACKGROUND: The incidence of intraneural injection during trainee anaesthetist ultrasound guided nerve block varies between 16% in experts and up to 35% in trainees. We hypothesized that elastography, an ultrasound-based technology that presents colour images of tissue strain, had the potential to improve trainee diagnosis of intraneural injection during UGRA, when integrated with B-Mode ultrasound onto a single image. METHODS: We recorded 40 median nerve blocks randomly allocated to 0.25 ml, 0.5 ml, 1 ml volumes to five sites, on both arms of two soft embalmed cadavers, using a dedicated B-Mode ultrasound and elastography transducer. We wrote software to fuse elastogram and B-Mode videos, then asked 20 trainee anaesthetists whether injection was intraneural or extraneural when seeing B-Mode videos, adjacent B-Mode and elastogram videos, fusion elastography videos or repeated B-Mode ultrasound videos. RESULTS: Fusion elastography improved the diagnosis of intraneural injection compared with B-Mode ultrasound, Diagnostic Odds Ratio (DOR) (95%CI) 21.7 (14.5 - 33.3) vs DOR 7.4 (5.2 - 10.6), P < 0.001. Compared with extraneural injection, intraneural injection was identified on fusion elastography as a distinct, brighter translucent image, geometric ratio 0.33 (95%CI: 0.16 - 0.49) P < 0.001. Fusion elastography was associated with greater trainee diagnostic confidence, OR (95%CI) 1.89 (1.69 - 2.11), P < 0.001, and an improvement in reliability, Kappa 0.60 (0.55 - 0.66). CONCLUSIONS: Fusion elastography improved the accuracy, reliability and confidence of trainee anaesthetist diagnosis of intraneural injection.
BACKGROUND: The incidence of intraneural injection during trainee anaesthetist ultrasound guided nerve block varies between 16% in experts and up to 35% in trainees. We hypothesized that elastography, an ultrasound-based technology that presents colour images of tissue strain, had the potential to improve trainee diagnosis of intraneural injection during UGRA, when integrated with B-Mode ultrasound onto a single image. METHODS: We recorded 40 median nerve blocks randomly allocated to 0.25 ml, 0.5 ml, 1 ml volumes to five sites, on both arms of two soft embalmed cadavers, using a dedicated B-Mode ultrasound and elastography transducer. We wrote software to fuse elastogram and B-Mode videos, then asked 20 trainee anaesthetists whether injection was intraneural or extraneural when seeing B-Mode videos, adjacent B-Mode and elastogram videos, fusion elastography videos or repeated B-Mode ultrasound videos. RESULTS: Fusion elastography improved the diagnosis of intraneural injection compared with B-Mode ultrasound, Diagnostic Odds Ratio (DOR) (95%CI) 21.7 (14.5 - 33.3) vs DOR 7.4 (5.2 - 10.6), P < 0.001. Compared with extraneural injection, intraneural injection was identified on fusion elastography as a distinct, brighter translucent image, geometric ratio 0.33 (95%CI: 0.16 - 0.49) P < 0.001. Fusion elastography was associated with greater trainee diagnostic confidence, OR (95%CI) 1.89 (1.69 - 2.11), P < 0.001, and an improvement in reliability, Kappa 0.60 (0.55 - 0.66). CONCLUSIONS: Fusion elastography improved the accuracy, reliability and confidence of trainee anaesthetist diagnosis of intraneural injection.
Authors: Mohamed Abdelmohsen Bedewi; Ayman A Elsifey; Mamdouh A Kotb; Abdelmohsen Mohamed Bediwy; Yasmin M Ahmed; Sherine Mohamed Swify; Ahmed M Abodonya Journal: Medicine (Baltimore) Date: 2020-09-11 Impact factor: 1.817