Assessment of quadriceps muscle thickness using bedside ultrasonography by nurses and physicians in the intensive care unit:Intra- and inter-operator agreement

BACKGROUND Data regarding the agreement among multiple operators for measurement of quadriceps muscle thickness by bedside ultrasonography(USG)are sparse.AIM To statistically assess the agreement among 5 operators for measurement of quadriceps muscle thickness on bedside USG.METHODS This was a cross-sectional observational study.The 5 operators of varied experience(comprised of 1 critical care consultant,2 fellows,and 2 nurses)independently measured quadriceps muscle thickness in triplicate for 45 critically ill patients each,using USG.Intra-and interrater agreement rates among the 5 operators were assessed using intraclass correlation coefficient(ICC)and expressed with 95%confidence interval(CI).RESULTS The 5 operators produced a total of 135 readings and 675 observations for ICC calculations to determine the intraoperator and interoperator variations respectively.For intraoperator agreement,the overall ICC(95%CI)was 0.998(0.997,0.999)for operator 1,0.998(0.997,0.999)for operator 2,0.997(0.995,0.999)for operator 3,0.999(0.998,0.999)for operator 4,and 0.998(0.997,0.999)for operator 5.For interoperator agreement,the overall ICC(95%CI)was 0.977(0.965,0.986;P<0.001)for reading 1,0.974(0.960,0.984;P<0.001)for reading 2,and 0.975(0.961,0.985;P<0.001)for reading 3.CONCLUSION USG measurement of quadriceps muscle thickness was not dependent on clinical experience,supporting training for nurses in it.