The Ratio Of Femoral Vein Diameter To Femoral Artery Diameter With Pulse Pressure Variation As A Diagnostic Tool
Condition: Mechanically Ventilated Patients
Study type: Interventional

Summary: 
      In assessing critically ill patients, an accurate assessment of a patient's volume status and
      whether they will respond to a fluid challenge with an increase in cardiac output is vital. 1
      When hypovolemia is detected, volume expansion is utilized to enhance hemodynamics and
      restore normal blood pressure. 2 Hemodynamic tests (right atrial pressure, pulmonary artery
      occlusion pressure, and cardiac output ) are used to assess preload in critically ill
      patients, although these indexes are not necessarily reliable predictors of fluid status.
      According to the Starling law, fluid administration is hypothesized to boost cardiac output
      by raising preload, which describes a positive relationship between cardiac muscle fiber
      length and contractility. However, the Starling curve hits a plateau beyond its ascending
      leg, and additional fluid administration can be hazardous, leading to right ventricular
      overload and pulmonary edema Invasive or noninvasive techniques can be used to determine
      blood volume status. Assessments such as central venous pressure (CVP) and mean pulmonary
      artery pressure (mPAP) are both invasive procedures. Various factors influence CVP (including
      thoracic, pericardial, abdominal pressures, etc.). CVP can be used as a fluid management
      indication, although It can be misused to estimate blood volume or mislead methods for
      treatment. Dynamic indices such as stroke volume variation (SVV) and pulse pressure variation
      (PPV) are superior to static indices for assessing volume status. However, these dynamic
      indices are unreliable when a patient is ventilated with low tidal volume, such as acute
      respiratory distress syndrome (ARDS); the tidal volume is insufficient to change
      intrathoracic pressure significantly. Ultrasound (US) evaluation of the inferior vena cava
      (IVC) may help determine fluid status.
    

Detailed description: 
      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

      Group(F) : (n=30), FVD/FAD ratio guided; US probe will be used first to find the bifurcation
      position of the femoral artery, and then the probe will be retracted proximally. The visual
      field of the bifurcation will disappear until the probe enters the main branch of the femoral
      artery, and the femoral artery and vein could be observed simultaneously. Under normal
      conditions, pulsation indicates the femoral artery, and its companion is the femoral vein.
      The mean FVD and FAD will be measured then the FVD / FAD ratio will be calculated.
    

Intervention name(s): FVD/FAD ratio guided; PPV
Intervention type(s): Procedure; Procedure
Intervention description(s): Ultrasound-guided ratio; PPV
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: group (F) FVD/FAD ratio guided
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Diagnostic
Keywords: mechanically ventilated patients; FVD / FAD