Spectral Analysis of Central Venous Pressure Waveform
Condition: Donor Hepatectomy; Central Venous Catheter; Hypovolemia
MeSH terms: Hypovolemia
Study type: Observational

Summary: 
      The use of central venous pressure has been abandoned for the assessment of intravascular
      volume status. The dynamic fluctuation of central venous pressure according to heart rate is
      quantitatively measured by spectral analysis of the central venous pressure waveform. Its
      clinical utility in the assessment of intravascular volume status is investigated.
    

Detailed description: 
      The use of central venous pressure, which is one of the static preload indices, has been
      abandoned for the assessment of intravascular volume status because of its unreliability. The
      static preload indices have been replaced with dynamic preload indices, such as stroke volume
      variation or pulse pressure variation because the dynamic preload indices reliably predict
      fluid responsiveness and perform better than the static preload indices. However, the
      periodic component of central venous pressure, which goes with cardiac cycles, has not been
      investigated. The power corresponding to heart rate from spectral analysis of central venous
      pressure waveform represents the extent of the dynamic fluctuation of central venous pressure
      and is assumed to reflect intravascular volume status. It is hypothesized that the spectral
      power of central venous pressure corresponding to heart rate represents intravascular volume
      status.
    

Intervention name(s): Placement of a central venous catheter; Monitoring of central venous pressure; Furosemide-induced hypovolemia before graft procurement; Replacement of fluid loss after graft procurement; Monitoring of stroke volume variation
Intervention type(s): Procedure; Device; Drug; Drug; Device
Intervention description(s): The right internal jugular vein is located at the first rib level under ultrasound-guidance. Using an out-of-plane technique, a needle is introduced into the lumen of the vessel. The aspiration of blood into the syringe connected to the hub of the needle confirms the placement of the needle tip in the lumen. After the syringe is detached from the needle, a guidewire is advanced into the vessel lumen through the needle. A dilator is introduced over the guidewire and subsequently is removed. Then, a central venous catheter is introduced over the guidewire into the vessel lumen through the pathway expanded by the dilator. The catheter tip is placed in the superior vena cava by inserting the catheter as far as the distance between the edge of the right transverse process of the first thoracic vertebra and the carina, which is preoperatively measured on a posteroanterior chest radiograph.; Following the placement of a central venous catheter, a fluid-filled system for monitoring central venous pressure is connected to the proximal lumen of the catheter. The reference transducer is placed at the level of 4/5 of the anteroposterior diameter of the thorax.; Patients fast from 10 pm the day before surgery. On the arrival at the operating room, an intravenous catheter for Plasmalyte infusion is placed into the right cephalic or basilic vein. The distal lumen of the central venous catheter is used for the infusion of 6% hydroxyethyl starch. Fluid requirements due to anesthesia, surgery, and no per os intake are not replaced by minimizing the administration of the fluids. Five minutes after the collection of the baseline data, 20 mg of furosemide is administered to promote diuresis for facilitating the venous outflow of the liver. An additional dose of furosemide 20 mg is given if the urine output is <1 ml/kg within 30 minutes after the first dose. Unless the second dose of furosemide produces >1 ml/kg of urine within 30 minutes, 40 mg of furosemide is administered. In the absence of effective diuresis (1 ml/kg within 30 minutes after each dose), the use of furosemide is abandoned and the patients are excluded from the study.; Immediately after the graft procurement, 500 ml of 6% hydroxyethyl starch are infused over 25 minutes. Afterward, Plasmalyte is infused at a rate of 10 ml/min until the end of surgery.; Following anesthesia induction, the right radial artery is catheterized. The catheter is connected to the EV1000 monitor (Edwards Lifesciences, Irvine, CA) through the FloTrac transducer (Edwards Lifesciences). The transducer is level with the one for central venous pressure monitoring. Using pulse contour analysis without external calibration, the stroke volume for each heartbeat is measured. At a 20-second interval, stroke volume variation is calculated as (maximum stroke volume - minimum stroke volume)/mean stroke volume.
Intervention MeSH terms: Furosemide
Observational model: Cohort
Time perspective: Prospective
Sampling method: Probability Sample
Study population: 
        Patients are recruited from a tertiary university hospital