Observational study in which pulse transit time (PTT) as a method and the device to register this data is compared with arterial blood pressure.

The population is composed of pediatric and adult patients in anesthesia or intensive care in need of arterial blood pressure monitoring.

Plan to enroll patients who accept the terms of the study consecutively. The population is composed by pediatric and adult patients in anesthesia and intensive care in need of close blood pressure monitoring.

After informed consent from the patients themselves, patient and parents and sometimes only parents.

The device measuring PTT is the prepared and calibrated with existing arterial blood pressure. Data is then recorded via the storage capacity of the device and via videocamera. The videocamera is used to identify large disturbances in data registration. This is to identify confounding data and in the end calibrate the device to be more accurate.

Data from the PTT device and the camera is then downloaded to the study computer and to an external hard drive in order to create redundancy in data storage.

Data is then analysed to compare the difference between data recorded from the PTT device and arterial pressure respectively. Aim is to be able to collect sufficient data to be able to decide wether to recommend or advice against clinical use.

Patient data is registered and then handled by our departmental clerk. Data is stored for ten years.

Inclusion Criteria:

• Arterial line planned or existing

Exclusion Criteria:

• suspected major perioperative hemodynamic variation.
• non existing consent.

Pediatric and adult patients in anesthesia or intensive care.

Anonymous data will be made available to interested researchers after publication. The patients are informed of this fact.

Supporting information will be made available after publication.

Data and supporting information will be made available to interested researchers upon request.