Prediction of Arterial Lactate and Blood Gas Values Through the Analysis of Central Venous Blood

Study Overview
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Brief Summary
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Predicting arterial lactate and blood gas values with sufficient accuracy by simply analyzing central venous blood would be interesting in intensive care unit patients in whom the insertion of an arterial catheter or arterial punctures could be avoided. This prospective study aims at externally validating published mathematical models built to predict arterial values from central venous blood analysis.

Detailed Description
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Mathematical models for predicting arterial blood gas and arterial lactate have recently be published (PMID 27543529; see the citations section). The aim of the study is to externally validate these models in a multicenter (11 centres in France) cohort of intensive care unit patients suffering from acute circulatory failure. For the peru pose of the study, patients will undergo concomitent central venous/arterial blood sampling from 1 to 4 times during their intensive cafe unit stay. Clinical characteristics of the patients and central venous blood gas and lactate values will be used to predicted arterial values according to previously published formula. Predicted and actual arterial values of each variable of interest (pH, PaCO2, SaO2, lactate) will then be compared.

Official Title
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Prediction of Arterial Lactate and Blood Gas Values Through the Analysis of Central Venous Blood. A Human, Prospective, Multicenter Validation Study.

Conditions
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Circulatory Failure

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: age>18 years patient admitted in a intensive care unit patient already carrying an indwelling arterial catheter and a superior vena cava central catheter patient presenting an acute circulatory failure defined by the presence of at least two of the following items: a) Persistent hypotension (systolic arterial blood pressure < 90 mm Hg or mean arterial pressure < 65 mm Hg) or need for continuous intravenous vasopressor treatment (at any dose). b) Presence of at least one of the following signs of hypoperfusionfusion :Change in mental status ; Skin mottling ; Oliguria (Urine output <0.5 ml/kg body weight for at least one hour); Arterial lactate > 2 mmol/l or peripheral venous lactate > 3.2 mmol/l; ScvO2 <70%. Routine medical management requires central venous blood sampling for ScvO2 measurement and arterial blood sampling for gazometry. Exclusion Criteria: Opposition to participation in the study Impossibility to take a concomitant arterial and venous gazometric sample. Patient treated with ECMO (extracorporeal membrane,oxygrnation), intermittent dialysis or continuous dialysis during sampling Patient hospitalized without consent and/or deprived of liberty by court decision.

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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What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Percentage error rate when predicting arterial values (pH, PaCO2, SaO2 and lactate) from central venous values. | For each variable of interest (pH, PaCO2, SaO2 and lactate), the percentage of predicted values outside the agreement interval obtained in a previously published study (i.e., -0.078 to +0.084 for arterial pH; -1.32 to +1.36 kPa for PaCO2; -5.15 to +4.47% for SaO2; 1.07 to +1.05 mmol/l for arterial lactate) will be calculated. | 15 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Bias and agreement interval between predicted and actual arterial values for each variable of interest. |  | 15 minutes | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Lactate, arterial blood gas, central venous blood, gazometer