The Impact of Different Recovery Positions on the Perfusion of the Lower Forearm and Comfort

Study Overview
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Brief Summary
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Introduction: A side-lying recovery position is recommended when victims are unresponsive but breathing normally and, hence, do not require cardiopulmonary resuscitation. In 2021, the European Resuscitation Council (ERC) and the Belgian Red Cross-Flanders issued new guidelines which included the description of a modified recovery position to avoid problems in victims with joint stiffness and to overcome potential obstructed venous return in the dependent arm. Based on good practice insights, the dependent arm will now be extended and not bent to support the other arm. However, there is currently no evidence available to support a specific recovery position. Objectives: The aim of this study is to assess the impact of different recovery positions on perfusion of the forearm and associated comfort. Methods: In this cross-over randomized controlled trial, 24 healthy volunteers will be placed in either the lateral recovery position with extended dependent arm or with bent arm, and in the other position thereafter. Before and between both recovery positions, the volunteers will be positioned supine for 15 min. Several perfusion indices of the forearm will be non-or mildly invasively monitored in the respective recovery positions by radial artery tonometry, ulnar artery echo doppler and venous congestion plethysmography. Subjective participant's discomfort and pain will be assessed as well. Differences in continuous outcomes between the different recovery positions will be assessed with paired t-tests or wilcoxon signed-rank test. Discussion: The benefit of lateral positioning of adults and children with decreased level of consciousness has been widely accepted despite limited supportive scientific evidence. We here will provide direct evidence (i) whether venous drainage in the dependent limb is impaired when positioning the victim in the lateral recovery position with bent arms and (ii) whether this potential complication can be minimized by extending the dependent arm. The major limitations of this study is that healthy volunteers, instead of non-responsive victims, are included as participants, and that the study will be performed in a highly controlled environment. Nevertheless, the generated insights will directly fuel evidence-based treatment recommendations regarding the recovery position in first aid settings, and fill a current gap in evidence.

Official Title
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The Impact of Different Recovery Positions on the Perfusion of the Lower Forearm and Comfort Associated With the Positioning: a Cross-over Randomized Controlled Trial

Conditions
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Unconsciousness

Intervention / Treatment
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* Other: recovery position


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: -healthy volunteers Exclusion Criteria: History of any coronary or peripheral vascular disease such as Raynaud's disease or thromboangitis obliterans (self-declared) Type I or type II diabetes (self-declared) Intake of cholesterol-lowering medication (self-declared) High blood pressure (systolic blood pressure > 140 mmHg and/or diastolic blood pressure > 90 mmHg) and/or use of antihypertensive drugs (self-declared) Obesity (BMI > 30 kg/m2) Smoking or using tobacco products (self-declared)

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 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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Design Details

Primary Purpose: Supportive Care
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: This study is a cross-over Randomized Controlled Trial in which the sequence of the lateral recovery position will be randomized.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Lateral side-lying recovery position with extended arm<br>The lateral side-lying recovery position with extended arm is directly based on the revised 2021 ERC guidelines recommending to extend the dependent arm and placing it next to the creased upper lying arm, which supports the head. | Other: recovery position<br>* A side-lying recovery position is a first aid intervention that can be performed by laypeople when victims are unresponsive but breathing normally and, hence, do not require cardiopulmonary resuscitation.<br>|
| Active Comparator: Lateral side-lying recovery position with bent arms<br>In the lateral side-lying recovery position with bent arms, the elbow of the dependent arm will now be bent with palm up and the far knee still flexed. | Other: recovery position<br>* A side-lying recovery position is a first aid intervention that can be performed by laypeople when victims are unresponsive but breathing normally and, hence, do not require cardiopulmonary resuscitation.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Difference in peripheral arterial pressure (PAP) | extracted from pulse wave amplitude (PWA) measured by radial artery tonometry | between 10 to 15 min in each position | 
| Cross-sectional area of the ulnar artery (SU) and peak systolic velocity of the ulnar artery (PSVU) of the hand of the dependent arm | measured by echo doppler | between 10 to 15 min in each position | 
| Peripheral venous pressure (PVP) | measured at the forearm and the back of the hand by venous congestion plethysmography | between 10 to 15 min in each position | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Oxygen saturation |  | measured continuously during 1u15 min (15 min supine position, 15 min posture 1, 15 min supine position, 15 min posture 2, 15 min supine position) | 
| Heart rate |  | measured continuously during 1u15min (15 min supine position, 15 min posture 1, 15 min supine position, 15 min posture 2, 15 min supine position) | 
| Discomfort (experienced by participant) | 10-point Likert-scale completed by the participants | after 15 min in the recovery position | 
| Pain (experienced by participant) | 10-point Likert-scale completed by the participants | after 15 min in the recovery position | 
| Skin discoloration | 10-point Likert-scale completed by the researcher | after 15 min in the recovery position | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Recovery position, First aid for unconsciousness, Arterial flow