Skip to main content

Muscle wasting in the ICU can be reliably monitored using ultrasound


The aim of this study was to establish the intraobserver and interobserver variation of ultrasonographic measurements of the rectus femoris muscle cross-section area (RF-CSA). Muscle wasting is frequent in the ICU, affecting more than one-half of the patients with severe sepsis [1]. Muscle mass reduces rapidly, and 15 to 20% is lost within the first week [1]. To monitor muscle mass, ultrasound has the benefits of being both readily available in the ICU and non-invasive. Ultrasonographic measurement of RF-CSA has an almost perfect correlation with MRI (mean interclass correlation (ICC) = 0.999) [2] and RF-CSA is linearly related to maximum voluntary contraction strength in both healthy subjects and COPD patients (r = 0.78) [3].


The study had two purposes: to determine the intraobserver variation for RF-CSA by one observer scanning 15 healthy adult volunteers three times each at 2-day intervals; and to determine the interobserver variation for RF-CSA by two observers each scanning 15 adult ICU patients on the same day. Patients were in a supine position, legs in passive extension. The transducer was placed perpendicular to the long axis of the right thigh over the RF, two-thirds of the distance from the anterior superior iliac spine to the superior patellar border [1]. RF-CSA was calculated by planimetry. At each scan, three measurements were made. For intraobserver variation, the 3 × 3 scans were analyzed using the interclass correlation coefficient. For interobserver variation, the three measurements from each observer were averaged and compared using Bland-Altman statistics.


Intraobserver variation: 15 healthy adults, age 39.6 ± 2.4 years, weight 66.8 ± 2.3 kg, sex three male/12 female. ICC: 0.996 (95% CI: 0.990 to 0.998). Interobserver variation: 15 ICU patients, age: 77 ± 8.3 years, weight: 71.3 ± 9.1 kg, sex nine male/six female. Bland-Altman: bias: -0.07 cm2, 95% limits of agreement -0.188 to 0.048 cm2.


Ultrasonographic measurement of RF-CSA is easily learned and quickly performed. It has a very low intraobserver and interobserver variation and can be recommended as a reliable method for monitoring muscle wasting in the ICU.


  1. 1.

    Parry SM, et al.: BMJ Open. 2012, e001891. doi:10.1136/bmjopen

    Google Scholar 

  2. 2.

    Reeves ND, et al.: Eur J Appl Physiol. 2004, 91: 116-118. 10.1007/s00421-003-0961-9

    Article  PubMed  Google Scholar 

  3. 3.

    Seymour JM, et al.: Thorax. 2009, 64: 418-423. 10.1136/thx.2008.103986

    Article  CAS  PubMed  Google Scholar 

Download references

Author information



Corresponding author

Correspondence to H Jørgensen.

Rights and permissions

This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated in a credit line to the data.

Reprints and Permissions

About this article

Cite this article

Jørgensen, H., Nedergaard, B. & Gilsaa, T. Muscle wasting in the ICU can be reliably monitored using ultrasound. Crit Care 17, P439 (2013).

Download citation


  • Maximum Voluntary Contraction
  • Anterior Superior Iliac Spine
  • Healthy Adult Volunteer
  • Interclass Correlation
  • Interobserver Variation