Validation of Nexfin Cardiac Output in Elderly Patients With Hip Fracture

Study Overview
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Brief Summary
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Measurement of how much blood the heart pumps may be useful in guiding how much intravenous fluid to give patients during surgery. The current monitors either require special drips (arterial and/or central lines) or a probe inserted into the oesophagus (food pipe) which may limit their use. Newer monitors are available which are completely non-invasive and seem to work well in younger patients. Patients with hip fracture are elderly and frail. The investigators wish to see whether the newer non-invasive monitor works well enough compared to the current monitors in this group of patients. If it does this may allow more of these patients to be monitored in this way.

Detailed Description
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The investigators wish to compare the accuracy of the newer, non-invasive monitor (Nexfin) against a more established minimally invasive monitor (LiDCO). The LiDCO has a calibration system which allows the absolute accuracy of the Nexfin to be established.

Official Title
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Validation of the Nexfin Non-invasive Cardiac Output Monitor in Patients Undergoing Hip Fracture Repair

Conditions
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Hip Fractures, Anesthesia

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Aged over 80 Able to give their own informed consent Exclusion Criteria: Severe valvular heart disease Taking lithium

Ages Eligible for Study
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Minimum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Bias and limits of agreement of Nexfin recorded cardiac output compared with LiDCOplus | Analysis of agreement between Nexfin cardiac output and the calibrated cardiac output measured by LiDCOplus | During anaesthesia period of surgery - measurements will be complete within 30 minutes of starting anaesthesia | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Bias and limits of agreement for change in cardiac output measured by Nexfin compared with LiDCO | Comparison of relative changes in cardiac output recorded by Nexfin and LiDCO in response to intra-anaesthesia / intra-operative events (fluid administration, drug administration) | During anaesthesia period of surgery - measurements will be complete within 30 minutes of starting anaesthesia | 
| Utility of Nexfin monitor | Proportion of time during anaesthesia and surgery when a valid signal is obtained from the Nexfin device. | Intra-operative - average duration about 1 hour | 
| Adverse events associated with Nexfin monitor | Recording of adverse events associated with use of the Nexfin monitor | Intra-operative - average duration about one hour | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Cardiac output, Stroke volume