Study on Baroreceptor Function in Relation to Orthostatic Blood Pressure Regulation After Hip Surgery

Study Overview
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Brief Summary
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The purpose of this observational study is to evaluate the baroreceptor function in relation to surgical inflammation and orthostatic intolerance after elective hip arthroplasty. The main hypothesis is that baroreceptor function is attenuated after surgery and related to surgical inflammation.

Detailed Description
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Orthostatic intolerance and hypotension is prevalent during early mobilization after major surgery. This observational study aims to evaluate the baroreceptor function during using a standardized evaluation protocol before, 6- and 24 hours after elective primary unilateral hip-arthroplasty. The study hypothesis is that baroreceptor function as expressed by the valsalva ratio is attenuated after surgery and related to surgical inflammation.

Official Title
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Baroreceptor Function and Inflammation in Relation to Orthostatic Intolerance During Early Mobilization After Elective Hip Arthroplasty

Conditions
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Hypotension, Orthostatic, Total Hip Replacement

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Scheduled for unilateral hip arthroplasty 18 years or older Able to give informed consent Exclusion Criteria: American Society of Anesthesiologists (ASA) class 3 or higher Chronic arrythmia (Atrial fibrillation or other arrythmia) Incompensated ischaemic heart disease Mobilization restriction due to surgical reasons Medical complications during admission requiring transferral to other department

Ages Eligible for Study
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Minimum Age: 18 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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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Study cohort<br> | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in baroreceptor function from preoperatively to 6 hours after surgery | Change in baroreceptor function as expressed by change in the blood pressure valsalva ratio during a standardized assessment before and 6 hours after surgery. | 6 hours after surgery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Orthostatic response in blood pressure | The response in systolic and diastolic blood pressure during postural change from supine to standing | Preoperative, 6 and 24 hours after surgery | 
| Orthostatic response in heart rate variability | Heart rate variability during supine rest, sitting and standing as assessed by Spectral analysis. | preoperative, 6 and 24 hours postoperative | 
| Orthostatic intolerance | Orthostatic intolerance defined as the inability to sit or stand for 3 minutes due to presyncopal symptoms (Dizziness, Nausea, Blurred vision). | preoperative, 6 and 24 hours after surgery | 
| Inflammatory markers | Inflammatory markers (CRP and interleukin-6) measured at 3 separate timepoint: preoperative, 6- and 24 h after surgery | preoperative, 6 and 24 hours postoperative | 
| Orthostatic Hypotension | orthostatic hypotension defined according to international guidelines. | Preoperative, 6 and 24 hours postoperative. | 
| Baroreceptor function | baroreceptor function as expressed by change in the blood pressure valsalva ratio during a standardized assessment | On the day of surgery: preoperatively, 6- and 24 hours after surgery | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Postoperative orthostatic intolerance, Surgical inflammatory response