In this clinical study the investigators will compare blood pressure measurements obtained using the non-invasive, continuous and wireless Biobeat monitoring device (a wrist watch or a patch configuration) to an invasive arterial line (radial or femoral) in 30 patients immediately after cardiac surgery, at the intensive care unit.

The Biobeat non-invasive, continuous and wireless monitoring device is based on photoplethysmograph technology. It measures several vital signs, including blood pressure, stroke volume, pulse rate, pulse pressure, heart rate variability, respiratory rate, saturation, cardiac output, cardiac index, and more. The data is transmitted to Biobeat's application (in both Apple and Google Play), and is available on the individual's cellular phone, tablet, or as a full monitoring system in a hospital department. The aim of this study is to compare the Biobeat monitor with the invasive method of blood pressure measurement, an arterial line. The study population includes 30 patients undergoing cardiac surgery. As per local protocol, each one of the participants will come out from the operating room with an arterial line. Once in the intensive care unit, the investigators will attach the Biobeat non-invasive monitor (either wrist watch or a patch, these two configurations are identical in terms of the monitoring system), and monitor the participants for 4 hours. Though both methods are continuous, the investigators will record the vital signs every 15 minutes during the 4 hours of the study.

Inclusion Criteria:

• Patients arriving immediately after cardiac surgery to the intensive care unit with an arterial line.

Exclusion Criteria:

• Refusal to participate
• Patients with no arterial line
• Pregnant women
• Individuals under the age of 18 years
• Patients with lack of judgment/mental illness
• Patients working in the Baruch Padeh Medical Center

30 patients immediately after cardiac surgery arriving to the intensive care unit, and connected to an arterial line transducer. Usually the arterial line is left for 24 hours. Right after arrival and once connected to an arterial line, the participants will be connected to the Biobeat monitor (either wrist watch or a patch). Vital signs will be monitored for 4 hours, and recorded every 15 minutes, for comparison. After 4 hours, the Biobeat monitor will be disconnected.

The investigators would probably share the results showing the level of agreement between the two measurement methods, but it will not be an individual data, rather the whole group, without any personal data included.