Sonographer-rated Effort Is Superior to Examination Time as a Method of Measuring Workload in the Vascular Laboratory

Abstract

Managing and equitably attributing workload in the vascular laboratory is challenging because of the wide variety of examinations that sonographers perform. We developed an effort-based method of measuring sonographer workload in the vascular laboratory. Vascular sonographers (n = 11) at an academic medical center anonymously rated the overall effort required to perform 39 different examinations for which standard protocols existed. The overall effort to perform a unilateral lower extremity venous ultrasound for DVT was selected as the reference and arbitrarily assigned an effort level of 1. Sonographers then rated all other exams relative to the reference examination using a scale of 0.2 to 5.0 (0.2 being only one-fifth the effort of the reference examination and 5.0 requiring a five-fold greater effort). Perceived effort as rated by the sonographers was then correlated with the time required to perform all examination-related activities (electronic health record time stamps for n = 9822 examinations with complete start/end time data from June 1, 2021, through May 28, 2022) as well as experience (years since RVT certification). Mean effort ratings varied considerably across the 39 examinations, ranging from 0.68 ± 0.20 (unilateral endovenous laser treatment [EVLT] follow-up) to 3.61 ± 0.85 (abdominal venous ultrasound for pelvic pain), a >5-fold difference (Table). Mean coefficient of variation for rated effort across all studies was 0.27 (range, 0.14-0.47). Mean time to perform each examination ranged from 35 ± 12 minutes (unilateral EVLT follow-up) to 88 ± 29 (EVLT guidance), a 2.5-fold difference. Mean coefficient of variation for examination time across all studies was 0.32 (range, 0.11-0.53). There was a modest correlation between sonographer-rated effort and examination time (R = 0.56) (Figure). Mean duration of RVT certification was 12.2 ± 10.1 years (range, 1-39 years). There was no correlation between duration of RVT certification and rated effort for each examination. Sonographer-rated effort is a precise measure of workload in the vascular laboratory and is independent of experience. Although effort and examination time correlated modestly (R = 0.56), effort ratings produced greater dispersion (>5-fold difference between easiest/hardest examination) than did time (2.5-fold difference between shortest/longest examination) with equal or less variation. For instance, the longest examination (EVLT guidance) received an effort rating of only 1.74 (14th), whereas the study receiving the highest effort score (abdominal venous, 3.61) required a mean of 58 minutes (24th). Sonographer-rated effort scores likely incorporate additional elements of work such as mental and/or physical effort, required expertise and documentation complexity not captured by examination time alone.TableSonographer-rated effort and time to complete 39 different vascular laboratory examinationsExaminationRated effortEffort SDEffort CoVTime, minutesTime SDTime CoVUnilateral EVLT follow-up0.680.200.2935120.35PPG fingers0.850.330.3947240.51PPG toes0.910.290.3251250.49Unilateral LE US for DVT (reference)1----45160.36Unilateral UE US for DVT1.080.180.1749150.30ABI limited1.240.590.4770300.43Bilateral LE vein map for bypass1.240.500.4060320.53Bilat LE venous US (limited)1.330.260.1948160.33Bilat UE venous US (limited)1.370.450.3344160.36Unilateral UE artery US for pseudoaneurysm1.480.310.2155140.26WBI1.560.620.4054180.33Unilateral LE artery US for pseudoaneurysm1.610.500.3147170.36Unilateral carotid US1.690.600.3550160.32Bilateral LE artery US (limited)1.710.480.2857170.30EVLT guidance1.740.750.4388290.33Bilateral LE artery US for popliteal aneurysm1.740.500.2953180.34Bilateral LE venous US for DVT1.800.300.1753150.29Bilateral carotid US1.790.500.2853150.28ABI complete (segmentals)1.930.630.3252140.27Bilateral LE artery US for pseudoaneurysm2.000.650.3356170.30Bilateral UE veins US for DVT2.010.450.2361190.31AAA screen2.030.500.2546100.22Temporary artery duplex2.080.560.276270.11Intraoperative duplex (CEA/LE bypass)2.100.600.2956190.34TOS PPG arterial (limited)2.310.610.2656140.25Bilateral LE venous comp check2.150.440.2157170.30Unilateral UE fistula map2.570.740.2960170.29Unilateral LE artery US (native)2.590.490.1968290.43AAA duplex (known)2.600.500.1953120.23Graft surveillance2.740.540.2074270.37ABI exercise2.870.670.2386230.27Bilateral radial artery map2.960.770.2655130.23Bilateral LE artery US (native)3.040.710.2375290.39Mesenteric artery US3.060.640.2153110.21Fistula surveillance US3.160.670.2163160.25Unilateral LE venous reflux mapping3.340.720.2262160.26Aortoiliac artery US (native/EVAR)3.390.790.2385320.38Renal artery US3.480.500.1462150.24Bilateral UE fistula map3.510.840.2488260.30Abdominal venous US3.610.850.2358140.24AAA, Abdominal aortic aneurysm; ABI, ankle-brachial index; CEA, carotid endarterectomy; CoV, coefficient of variation; DVT, deep vein thrombosis; EVAR, endovascular aneurysm, repair; EVLT, endovenous laser treatment; LE, lower extremity; PPG, photoplethysmogram; SD, standard deviation; TOS,; US, ultrasound; WBI, whole body imaging. 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