Comparing The Ratio Of Femoral Vein Diameter To Femoral Artery Diameter With Pulse Pressure Variation As A Diagnostic Tool For Fluid Responsiveness In Mechanically Ventilated Patients; A Prospective Observational Study

The study will be conducted in intensive care units of Fayoum University Hospitals after approval of the local institutional ethics committee, and the local institutional review board will approve the study. The inclusion criteria will be as follows: patients on mechanical ventilation(MV), aged between 18 and 60 years with circulatory failure defined as mean arterial pressure (MAP) less than 65 mmHg or systolic arterial pressure less than 90mm Hg with signs of hypoperfusion (urinary flow < 0.5mL/kg/ min for > 2hr, tachycardia > 100 beats/min, or presence of skin mottling, and serum lactate more than 2 mmol/L) 17 and showing positive PLRT. The exclusion criteria: cardiac arrhythmias, previously known significant valvular disease or intracardiac shunt, air leakage through chest drains, increasing intraabdominal pressure, norepinephrine infusion as it decreases PPV and SVV, masking their ability for the detection of FR15

, peripheral vascular diseases, ARDS patients due to low tidal volume a, Contraindication for fluid administration as cardiogenic shock, acute pulmonary edema or LVEF% less than 50%. , renal patients with oliguria and volume overload including patients on hemodialysis or patients with acute anuric renal failure., patients with lower extremity artery/vein thrombosis, significant lower extremity artery plaque, lower extremity artery occlusion, inferior vena cava filter implantation, lower extremity varicose veins,

All patients fulfilling criteria will be monitored by (1) 6 leads ECG, (2) noninvasive BP, (3)urinary catheter for UOP, (4) pulse oximeter then divided into 2 groups, group (P) PPV guided group and group (F) FVD/FAD ratio guided

Randomization of patients to each of the treatment groups will be done by a statistician not involved in the study, using the website randomization.com. The allocation concealment will be done by contacting the statistician giving him the patient number, age, and sex to receive the patient allocation in a sealed envelop.

The envelope is to be received and opened after the informed consent is obtained Neither the participants, the study investigator, the attending clinicians, nor the data collector will be aware of groups allocation till the study end. The Consolidated Standards of Reporting Trials (CONSORT)recommendation will be followed. Group (P):(n=30), patients will be temporarily sedated and paralyzed and on fully controlled mechanical ventilation. No spontaneous breathing effort will be detected on the mechanical ventilator waveform monitor, ensuring that the respiratory changes in arterial pressure reflect only the effects of positive pressure ventilation. Modes of ventilation are selected to volume or pressure-controlled ventilation, depending on the decision of the primary physicians. A tidal volume will be set to not less than 8 ml/ kg (predicted body weight). The preset respiratory rate will be set at 14 breaths/min. Positive end-expiratory pressure (PEEP) will be between 8 and 10 cmH2O. The plateau pressure was kept at below 30 cmH2O. In all patients, radial artery cannulation will be done for invasive blood pressure monitoring (using a 20 G cannula), PPV is calculated directly on Nihon Kohden monitors at the base line then infusion of 4ml/kg /h of crystalloids will be infused till PPV will be less than 13%. 15