Postoperative Continuous Non-invasive Haemodynamic Monitoring on the Ward

Enrolled patients will have the CNAP sited in the post-anaesthetic care unit (PACU) and it will stay on their arm until at least 12 hours have passed. The device will collect continuous heart rate, blood pressure, and nominal cardiac output; it also derives a range of values from these measurements. There is minimal risk attributable to the use of the CNAP device. These devices are already in routine clinical use in the UK in intensive care units, high-dependency units and operating theatres. To reduce burden on the patient, no additional HR/BP monitor is required and whenever the usual care team would like to know the HR or BP these values will be displayed. The additional parameters (related to measurement of cardiac output) will not be shared with the clinical team - they will remain blinded to these data because otherwise there is the risk that they would use this additional information to alter clinical management. Medical notes will be examined to provide information about demographics, physical characteristics (height, weight), and previous medical history - please see case report form (CRF, appendix 1) for more details. There are no blood tests, or other acquisition of biological samples.