Measurement of Serum Potassium Rate During Accidental Hypothermia.

Study Overview
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Brief Summary
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Serum Potassium Rate (PR) is a key indicator for medical management of patients with accidental hypothermia particularly for hypothermia related cardiac arrest (CA). Experts recommend a cut-off value for PR of 12 mmol/l for all hypothermic victims and 8 mmol/l for avalanche casualties. Any patient presenting a PR lower than the cut-off value should be considered for Extracorporeal Rewarming. This therapeutic strategy is vital for patient survival. However, there is no consensus about what type of vessels should be punctured in order to obtain an accurate potassium rate and what type of measurement technics should be used to measure this potassium rate. The investigators hypothesize that potassium rate in these patients will differ by 1 mmol/l in blood samples collected from a peripheral vein in contrast to a central vein. The investigators study is a prospective observational, multicentre study.

Official Title
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A Comparative Study of Serum Potassium Rate Between Peripheral and Central Venous Sample Collection in Patients With Hypothermia Related Cardiac Arrest

Conditions
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Accidental Hypothermia, Hyperkalemia, Cardiac Arrest

Intervention / Treatment
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* Diagnostic Test: blood draw from three different vessels


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Hypothermia related cardiac arrest Age > 18 years Core temperature < 30° C measured in oesophagus at hospital admission Exclusion Criteria: Age < 18 years Known condition of pregnancy or breastfeeding women Evidence of trauma-related cardiac arrest Cardiac arrest in which reanimation is not justified (frozen body, final stadium of an incurable disease, advance health care directive)

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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Design Details

Primary Purpose: Diagnostic
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Hypothermia related cardiac arrest<br>blood draw from three different vessels punctured in the emergency room (central vein, peripheral vein, artery) and comparison of potassium rate and other biological values between the different sites of blood draw and two different measuring techniques (laboratory vs. blood gas analyser) | Diagnostic Test: blood draw from three different vessels<br>* Patient in cardiac-arrest and cold exposure, diagnostic test: blood draw from three different vessels (central vein, artery, peripheral vein) and measuring of PR<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Comparison of potassium rate in central venous blood and blood from a peripheral vein (measured in mmol/l) | Comparison of PR in central venous blood and blood from a peripheral vein (measured in mmol/l) | 24 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Comparison of potassium rate in venous and arterial blood (measured in mmol/l) | Comparison of potassium rate in venous and arterial blood (measured in mmol/l) | 24 hours | 
| Comparison of potassium rate from laboratory analysis and at bedside via blood gas analyser (measured in mmol/l) | Comparison of potassium rate from laboratory analysis and at bedside via blood gas analyser (measured in mmol/l) | 24 hours | 
| Comparison of the time difference between laboratory analysis and blood gas analyzer at bed side (measured in minutes) | Comparison of the time difference between laboratory analysis and blood gas analyzer at bed side (measured in minutes) | 24 hours | 
| Survival and neurological outcome as measured by the Cerebral Performance Category Scale | Survival and neurological outcome as measured by the Cerebral Performance Category Scale | 3 months | 
| Study of biological parameters to calculate the Strong Ion Gap (measured in mEq/l) according to the Stewart Approach | For each sample, the apparent strong ion difference (SIDa) will be calculated as SIDa =(Na+ +K+ +Ca2+ +Mg2+)-(Cl- +Lac-) The amount of weak plasma acid (A-) will be calculated as: A- = [Alb] × (0.123 × pH - 0.631) + [PO4] × (0.309 × pH - 0.469) The effective strong ion difference (SIDe) will be calculated as: SIDe = 1000 × 2.46 × 10-11 × PaCO2/(10-pH) + [A-] To quantify unmeasured charges, the SIG will be calculated as: SIG = SIDa - SIDe | 24 hours |