Published online Jul 26, 2020. doi: 10.4330/wjc.v12.i7.351
Peer-review started: February 29, 2020
First decision: April 7, 2020
Revised: May 11, 2020
Accepted: June 17, 2020
Article in press: June 17, 2020
Published online: July 26, 2020
Processing time: 146 Days and 5.9 Hours
Intensive care unit (ICU) acquired weakness (ICUAW) remains a major cause of mortality and morbidity in critically ill patients. Ultrasonography is a valid diagnostic tool in critical ill patients who present muscle weakness. Muscle wasting may occur in cardiac surgery patients’ post-ICU admission affecting outcome. Early detection of muscle wasting may benefit interventions to decrease the duration of mechanical ventilation, increase muscle strength and improve their quality of life.
Sonography is a diagnostic method that allows the assessment of muscle mass in bedridden. It has been introduced recently as a valid and reliable to measure quantity and quality of skeletal muscle. It's a non-invasive, low-cost method offering real-time imaging without radiation exposure.
The clinical value of ultrasound-assessed muscle mass in patients post-cardiac surgery ICU admission.
An observational study was conducted to 221 consecutive patients after cardiac surgery at the Cardiac Surgery ICU of Onassis Cardiac Surgery Center from February 1, 2018 to May 15, 2018. Sonographic assessment of quadriceps muscle thickness and evaluation of muscle strength using the Medical Research Council (MRC) scale were performed until 7th day post-ICU admission or ICU discharge.
Among the 165 patients finally included in the analysis [median age: 71 (64-77) years], there was a decrease of femoris muscle thickness by 2.2% [(95% confidence interval (CI): - 0.21 to 0.15), n = 9; P = 0.729] and vastus intermedius mass (RF_VI mass) decreased by 3.5% [(95%CI: - 0.4 to 0.22), n = 9; P = 0.530]. Patients with RF_VI mass below the recorded median values (2.5 cm) on day 1 (n = 80) had a longer ICU length of stay compared to those patients with RF_VI mass above than 2.5 cm (n = 85), (47 ± 74 h vs 28 ± 45 h, P = 0.02) and remained to MV more time, (17 ± 9 h vs 14 ± 9 h, P = 0.05). Patients with ICUAW on day 3 (n = 7) had prolonged ventilation (44 ± 14 h vs 19 ± 9 h, P = 0.006) compared to patients with no ICUAW (n = 33). Moreover, the duration of extracorporeal circulation was greater for patients with low MRC scale score on day 3 (n = 7) compared with patients with higher MRC scale score (n = 33), (159 ± 91 min vs 112 ± 71 min, P = 0.025).
The results of the study have shown that there is a trend to a decreased muscle mass in patients after cardiac surgery post-ICU admission. Patients with decreased muscle mass remained more on ventilator and stayed longer in ICU. Sonographic assessment seems to be a valid method to quantify quadriceps muscle mass in patients after cardiac surgery.
We advocate further research to investigate muscle wasting in patients after cardiac surgery in order to implement preventive measures for ICU acquired weakness. Furthermore, it is recommended to identify a standardized protocol for sonographic muscle mass assessment to be implemented in research studies and intervention protocols.