Use of a minimally invasive uncalibrated cardiac output monitor in patients undergoing cesarean section under spinal anesthesia: report of four cases.

Background And Objectives: Hemodynamic changes are observed during cesarean section under spinal anesthesia. Non-invasive blood pressure (BP) and heart rate (HR) measurements are performed to diagnose these changes, but they are delayed and inaccurate. Other monitors such as filling pressure and cardiac output (CO) catheters with external calibration are very invasive or inaccurate.