Intensive care unit -acquired weakness (ICU- AW) is a common consequence linked to a worse outcome as evidenced by prolonged mechanical ventilation, longer ICU stays, greater mortality rates and a lower quality of life for survivors, so early detection and treatment of ICU-AW are critical. However, there is no "gold standard" currently available for assessing and diagnosing ICU-AW. It's crucial to develop diagnostic methods that enable for early detection and risk stratification in all critically ill patients, such as:

GDF-15 (growth differentiation factor-15) is thought to be a mediator of muscle atrophy because its level increases in the muscular atrophy As a result, measuring GDF-15 seems promise for diagnosing muscle atrophy.

After obtaining the approval of research ethical committee of faculty of medicine, Minia university, written informed consent will be obtained from all participants or their legal representatives prior to study inclusion, this prospective cross sectional non randomized observational study will be conducted in intensive care unit Minia university hospital, on conscious non-mechanically ventilated patients with expected ICU stay 7 days or more during the period from January 2022 to December 2022. Based on inclusion and exclusion criteria, patients who met eligibility criteria, the prognosis and outcome of patients developing ICU-AW will be observed.

Parameters will be assessed:

1. Medical history, Age, gender, weight, BMI and APACHE II score ("Acute Physiology and Chronic Health Evaluation II") which is a severity-of-disease classification system one of several ICU scoring systems will be assessed in the day of admission.
2. SOFA score ("Sequential Organ Failure Assessment ") which will be assessed every day.
3. Routine lab investigations other than these in SOFA score as (Urea, Albumin, Hb, TLc, Pt, Ptt, RBG…..ect).
4. Urea:creatinine ratio: Urea and creatinine will be measured daily as a part of SOFA score and urea to creat will be calculated.
5. Plasma Growth differentiation 15 (GDF15) on 1, 4 and 7 days.
6. Ultrasound measurement of rectus femoris cross-sectional area (RFcsa) on 1, 4, 7, 10 and then every 3days according to patients stay in ICU.
7. Muscle Strength Assessment using the Medical Research Council (MRC) score on 1, 4 and 7 days where patients will be divided into an ICU-AW group and a non ICU-AW group according to their MRc-score on the 7th day.
8. Length of hospital and ICU stay.
9. Long term out come after 3 months survival, physical activity and return to work

Inclusion Criteria:

• age more than 18 conscious patients patients with expected ICU stay more than 7 days

Exclusion Criteria:

- unconscious patients spinal cord injury limb fracture or amputations history of cognitive dysfunction severe oedema end stage kidney disease

patients older than 18, conscious non mechanically ventilated patients and those with expected ICU stay more than 7 days during the period from September 2023 to September 2024