Postoperative Continuous Non-invasive Haemodynamic Monitoring on the Ward

Postoperative Continuous Non-invasive Haemodynamic Monitoring on the Ward: a Feasibility Study

The patient's clinical care will not be altered apart from an the use of a non-invasive monitor for a short time, without any biological sample acquisition, or follow-up. This is low risk.

The device works through a complex pressure measurement in the fingers and by slightly squashing the fingers it can cause minor impairments to circulation. This represents a very small risk. To mitigate this risk the investigators will exclude patients with impaired circulation to the fingers and fingers will be monitored.

The approach is necessarily on the day of surgery and for many people this is an anxious time. The investigators have a lot of experience of approaching patients on the day of surgery for providing consent for observational studies - the investigators use caution and sensitivity. The investigators do not approach patients who the clinical team consider anxious or where there is significant pressure on time.

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.

Inclusion Criteria:

• Has capacity to provide informed consent
• Surgery: planned or unplanned; all types including gastrointestinal, urology, orthopaedics and gynaecological
• Due for an inpatient stay (i.e. not day case surgery) on either Frensham or Bramshott wards (staff will have had training with the device on these wards)
• Aged 18 years or over

Exclusion Criteria:

• Admission to intensive care unit ICU / high dependency unit HDU
• Declines consent to participate, or lack capacity to provide consent
• Impaired circulation of the hands: Raynaud's disease or severe peripheral vascular disease.