Written by Chris Thom
Spoon Feed
In this single center study, POCUS assessment of quadriceps muscle thickness predicted length of stay within an inpatient medicine unit.
POCUS is often the last stop on the imaging train
120 adult patients aged 65 and older who were being admitted to an inpatient medicine service were consecutively enrolled. At the time of admission, POCUS was utilized to measure the quadriceps muscle thickness (MT) and muscle echo intensity (EI). The quadriceps MT was measured in the supine position at the midpoint between the greater trochanter and lateral condyle of the femur. The rectus femoris and vastus intermedius were summated to measure MT. EI was defined with a score of 0 (black) to 255 (white). Length of stay (LOS) was recorded and categorized into greater or less than 30 days. The Charlson Comorbidity Index was also calculated as a comparator tool for predicting LOS.
Patients with LOS greater than 30 days had lower MT than those with < 30 day LOS (mean 17 mm vs. 21 mm, p < 0.0001). In multivariate linear regression analysis, one unit increase in MT was associated with 1.5 fewer days of LOS. High muscle EI was not statistically significant in its association with LOS. The association between MT and LOS persisted and remained significant after adjusting for the CCI score.
How does this change my practice?
This is a novel usage of POCUS that appears to have good predictive value for increased LOS among patients admitted to an inpatient medicine service that independently predicts LOS. It appears easy to perform and could be quickly added in conjunction with other existing variables and might even lend itself to an AI predictive model to estimate hospital or internal medicine capacity.
POCUS pro-tips and clips:
I will often sonographically interrogate the muscle layer for foreign body evaluations, hematoma assessment, or when suspecting deep soft tissue infection such as pyomyositis or necrotizing fasciitis. The first step is to get comfortable with what’s normal. You can do this during joint evaluations, DVT scans, US IV placement, etc. The muscle will appear as a hypoechoic, “speckled” structure just underneath the subcutaneous tissue layer. You can then start to recognize when there is abnormal edema or echogenicity in the muscle layer and also accurately identify the borders of the muscle tissue for thickness measurement. Another helpful tip is that the muscle will often be directly bordered by an echogenic layer of fascial tissue.
Source
Quadriceps muscle thickness as measured by point-of-care ultrasound is associated with hospital length of stay among hospitalised older patients. Age Ageing. 2025 Mar 28;54(4):afaf103. doi: 10.1093/ageing/afaf103. PMID: 40237716; PMCID: PMC12001769.
