Pleth Variability Index in Modified Prone Position or Knee-chest Position (Concord Position)

Pleth Variability Index as Predictors of Fluid Responsiveness in Modified Prone Position(Concord Position) or Knee-chest Position

To investigate whether PVI predicts the fluid responsiveness in modified prone position undergoing posterior approach cervical operation. Furthermore, modified prone position could influence on dynamic variables including stroke volume variation(SVV), pulse pressure variation(PPV) and PVI.

Objective :

To compare measurements of pleth variability index (PVI), pulse pressure variation (PPV) and stroke volume variation (SVV) to predict fluid responsiveness in modified prone position or knee-chest position (concord position) for cervical operation.

To identify Influence of the modified prone position (concord position) on these variables.

Method

1. To assess influence of the position change on PVI and other variables(PPV, SVV)
2. To assess PVI to predict fluid responsiveness at modified prone position

Inclusion Criteria:

• American Society of Anaesthesiologists'(ASA) physical status 1-3
• patients who received cervical operation in modified prone position or knee-chest position

Exclusion Criteria:

• Valvular heart disease
• Congestive heart failure, reduced left ventricular function ( Ejection fraction < 40%)
• Moderate grade of pulmonary disease
• Arrhythmia (atrial fibrillation, atrial flutter.. etc.)
• body mass index > 30 or < 15 kg/m2