Non-invasive Identification of Preoperative Anaemia

Study Overview
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Brief Summary
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Approximately 20% of patients undergoing elective orthopaedic surgery are anaemic. When not identified and treated before surgery, this can lead to requiring blood transfusions, which brings additional expenses, time and inconvenience to the patient.It is recommended that preoperative assessment involves investigation and where possible, treatment of anaemia. The timescale between assessment and surgery makes it difficult to comply with guidelines without postponing surgery. This study will investigate adult patients scheduled for elective orthopaedic surgery, where a full blood count is to be taken as part of routine care. A paired non-invasive reading of their blood will be taken. It will be conducted at The Royal Infirmary, Edinburgh. This device is not in use within the department currently but has been given free of charge for the study. There are no restrictions placed on the device except that it is not accurate for measuring haemoglobin <8g.dL. Participant care will only be determined by results from the laboratory assay as per routine care, not the noninvasive device. The device is CE marked for haemoglobin determination. Masimo (manufacturer) have released results in the accuracy of their monitor but with very little other information, for example, study population or precision. This study aims to answer how accurate and precise non-invasive measurements are in patients scheduled for orthopaedic surgery (there are no studies with these results) and whether anaemia can be identified earlier in the patient pathway i.e. an anaemia screen at time of surgical listing, therefore leaving ample time for treatment and optimisation of care. The data from the study will not be shared with Masimo. There is ongoing work towards introducing and piloting a new pre-operative triage system where optimisable conditions e.g. anaemia are identified at the time of listing. This study would aid this work.

Official Title
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NIPPA: Non-Invasive Haemoglobin Measurement to Identify Preoperative Anaemia in Patients Scheduled for Elective Orthopaedic Surgery, a Single-centred Prospective Cohort Study.

Conditions
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Anemia

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: able to provide informed consent aged between 16-80 years old scheduled for elective orthopaedic surgery a full blood count (FBC) is to be taken as part of routine care Inclusion Criteria for healthy volunteers cohort: able to provide informed consent aged between 16-80 years old Exclusion Criteria: Patients with haemoglobin disorders Raynaud's disease (or any other condition affecting the blood supply to the digits). Exclusion Criteria for healthy volunteers cohort: Patients with haemoglobin disorders Raynaud's disease (or any other condition affecting the blood supply to the digits).

Ages Eligible for Study
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Minimum Age: 16 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Patients undergoing elective orthopaedic surgery<br> | |
| Healthy Volunteers<br> | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The accuracy of the non-invasive device | assessed by calculating the agreement between the results obtained from the gold standard laboratory assay and the non-invasive device | January to March 2020 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Correlation of the non-invasive device to the gold standard | Intraclass correlation coefficient | January to March 2020 | 
| Correlation of the non-invasive device to the gold standard | Interclass correlation coefficient | January to March 2020 | 
| Predictive value of the non-invasive device | sensitivity | January to March 2020 | 
| Predictive value of the non-invasive device | specificity | January to March 2020 | 
| Predictive value of the non-invasive device | positive predictive value | January to March 2020 | 
| Predictive value of the non-invasive device | negative predictive value | January to March 2020 | 
| Factors independently associated with bias | age in years | January to March 2020 | 
| Factors independently associated with bias | sex (male or female) | January to March 2020 | 
| Factors independently associated with bias | perfusion index measured by noninvasive device | January to March 2020 | 
| Factors independently associated with bias | pleth variability index measured by noninvasive device low signal quality | January to March 2020 | 
| Factors independently associated with bias | heart rate measured by noninvasive device low signal quality | January to March 2020 | 
| Factors independently associated with bias | SpO2 (peripheral oxygen saturation) measured by noninvasive device low signal quality | January to March 2020 | 
| Factors independently associated with bias | low signal quality measured by noninvasive device low signal quality | January to March 2020 |