The purpose of this study is to compare blood pressure values (systolic, diastolic, mean arterial pressure) and waveform as recorded by a radial arterial line catheter to the waveform and values as calculated by the Sensifree's algorithm from a PPG sensor from a variety group of patients during elective surgeries.

Before induction of anesthesia, an arterial line will be inserted to the patient radial artery using a designated short, stiff tubing kit according to catheter IFU (Instructions for Use), preferably under US guidance. Removal of air bubbles from the catheter-transducer system is mandatory prior to connecting the tubing to the catheter.

Study nurse will connect a Sensifree laptop with designated data acquisition software (Medicollector BEDSIDE) to the multi-parameter monitor communication port and start the recording of invasive blood pressure and pulse oximeter pleth (PPG sensor) per software IFU. Prior to connecting the arterial line system to the patient, a calibration (flush test) will be done and recorded. During the study, any deterioration in the waveform recorded by the intra-arterial catheter will be noted and appropriate corrective measures will be taken as soon as possible (e.g., flushing or adjusting the position of the catheter).

Preferable NIBP (Non Invasive Blood Pressure) measurement rate will be every 10 minutes, unless the medical procedure requires otherwise.

Calibration procedure will be repeated every 60 +/- 5 minutes and at the end of the surgery. Recording will take place for the duration of the surgery.

NIBP cuff will be placed over the arterial-line arm, NIBP air hose will be replaced with an air hose supplied by Sensifree and the pressure gauge in it will be connected to Sensifree laptop via analog to digital converter in order to capture the data.

Medication used during the surgery will be listed and documented in the CRF (Case Report Form) including drugs name, dose, time and method of administration.

Offline data analysis will compare the blood pressure values as calculated by the Sensifree's algorithm based on the PPG signal, to the values obtained from the arterial line. The comparison results will be measured against the accuracy performance requirements per ISO 81060-2.

Inclusion Criteria:

• Signed inform consent
• Age 18-20
• Elective surgery that requires invasive BP monitoring (A-line)

Exclusion Criteria:

• Emergency surgery
• Subject has a condition that might prevent BP fluctuations
• Subject is taking medicine that might prevent BP fluctuations
• Arterial line not placed in the radial artery
• Flush test has inadequate frequency response pre-trial
• Subject's arterial line contralateral hand is not available for PPG sensor placement
• Subject has 50% or more pacemaker dependency

Patients scheduled for elective surgery involving placement of radial artery A-line for BP monitoring