Samuel C. Smith

Compression feedback devices over estimate chest compression depth when performed on a bed

INTRODUCTION CPR feedback/prompt devices are being used increasingly to guide CPR performance in clinical practice. A potential limitation of these devices is that they may fail to measure the amount of mattress compression when CPR is performed on a bed. The aim of this study is to quantify the amount of mattress compression compared to chest compression using a commercially available compression sensor (Q-CPR, Laerdal, UK). A secondary aim was to evaluate if placing a backboard beneath the victim would alter the degree of mattress compression. METHODS CPR was performed on a manikin on the floor and on a bed with a foam or inflatable mattress with and without a backboard. Chest and mattress compression depths were measured by an accelerometer placed on the manikins chest (total compression depth) and sternal-spinal (chest) compression by manikin sensors. RESULTS Feedback provided by the accelerometer device led to significant under compression of the chest when CPR was performed on a bed with a foam 26.2 (2.2)mm or inflatable mattress 32.2 (1.16)mm. The use of a narrow backboard increased chest compression depth by 1.9mm (95% CI 0.1-3.7mm; P=0.03) and wide backboard by 2.6mm (95% CI 0.9-4.5mm; P=0.013). Under compression occurred as the device failed to compensate for compression of the underlying mattress, which represented 35-40% of total compression depth. CONCLUSION The use of CPR feedback devices that do not correct for compression of an underlying mattress may lead to significant under compression of the chest during CPR.

PWE-048 The virtual electronic chromoendoscopy score in ulcerative colitis exhibits very good inter-rater agreement in scoring mucosal and vascular changes after computerised module training: a study across academic and community practice

Introduction Mucosal healing is the desired therapeutic endpoint for clinical trials in ulcerative colitis (UC). However, conventional white light endoscopy may fall short of capturing the full spectrum of inflammatory change; and virtual electronic chromoendoscopy (VEC) can show ongoing disease activity even when Mayo scores suggest healing (Iacucci et al. Endoscopy 2015 and 2017). Applicability of VEC scoring requires determination outside the expert setting; thus, our aim was to provide external validation among trainees, consultant gastroenterologists and colorectal surgeons, practicing across six general and specialist centres. Method 15 participants reviewed a computerised training module outlining HD and i-Scan modes. Anchor points for the VEC score indicated mucosal changes (crypt distortion, 0 [A–C]; microerosions, I [1–3]; erosions, II [1–3]; and ulceration, III [1–3]) and vascular alterations (non-dilated vessels, 0 [A–C]; dilated/crowded vessels, I [1–3]; mucosal bleeding, II [1–3]; and intraluminal bleeding, III [1–3]). Performance accuracy was tested using a video library pre-/post-training (n=30). Agreement between raters was tested for the Mayo score, UCEIS and VEC score, and results correlated with histology (New York Mount Sinai system). Results The inter-rater agreement was very good for the Mayo score, UCEIS scoring erosions/ulcers and overall, and for VEC scoring mucosal patterns in both modules (Table 1). For the vascular components of UCEIS agreement was only moderate, and did not improve post-training; unlike the agreement for VEC vascular patterns which improved significantly to very good. Correlation between histology and VEC score was highly significant for mucosal and vascular scoring (Spearman’s ρ: 0.910, p<0.001; and 0.907, p<0.001; respectively, Figure 1). This was superior to the Mayo score (0.876, p<0.001) and UCEIS (0.887, p<0.001). Conclusion The VEC score demonstrates very good inter-observer agreement across all levels of experience and provides excellent correlation with histology. Unlike UCEIS, the VEC score does not have subjective elements (e.g. mucosal erythema, incidental/contact friability) and may better delineate vascular changes due to filter technology. Given the ability to define subtle endoscopic features, VEC may be applied to further stratify treatment paradigms for patients with UC. Disclosure of Interest P. Trivedi Conflict with: Received funding from the National Institute for Health Research (NIHR), Conflict with: This article presents independent research funded by the NIHR. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health, S Ghosh: None Declared, M Iacucci: None Declared Abstract PWE-048 Table 1 Abstract PWE-048 Figure 1