Study on the Repeatability of Cardiac Output Measurements Dependence of Temperature of Injectate

Study Overview
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Brief Summary
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This study tests the reliability of thermodilution cardiac output measurements with pulmonary artery catheters in immediate connection with heart surgery. In accordance with our clinical practice, thermal indicator injections are synchronized with respiration. The impact on measurement repeatability of spontaneous vs artificial ventilation and the effect of the injectate temperature is tested. The study hypothesis is that when injections are synchronized with the respiration, only three injections at room temperature are needed to be within 5 % of the true cardiac output in mechanically ventilated patients.

Detailed Description
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Bolus thermodilution cardiac output measurements by means of a pulmonary artery catheter have been a mainstay of monitoring critically ill patients for more than thirty years. Recent studies have questioned wether the traditional practice of averaging measurements from tree room temperature thermal indicator injections give sufficient precision. This study tests the number of indicator injections necessary to be within 5 % of the true cardiac output (taken as the average of 16 injections) when the injection is synchronized with the respiration. The reliability of the thermodilution measurements are tested A) in sedated, artificially ventilated cardiac surgical patients and B) in the same patients when postoperatively awake and spontaneously breathing. We further compare the use of room temperature and iced thermal indicator injections. The study hypothesis is that when injections are synchronized with the respiration, only three injections at room temperature are needed to achieve the desired precision in mechanically ventilated patients. Only patients receiving a pulmonary artery catheter according our institution standard procedure of care will be included.

Official Title
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The Impact of Temperature of the Injectate on the Precision (Repeatability) of Cardiac Output Measurements Synchronized With the Respiration (the Temperature Study)

Conditions
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Heart Diseases

Intervention / Treatment
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* Device: Pulmonary artery catheter


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Cardiac surgical patients who receive a pulmonary artery catheter according to the institution clinical criteria - Exclusion Criteria: Acute cardiac surgery Preoperative arrythmias

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 85 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

| Intervention/Treatment |
| --- |
|Device: Pulmonary artery catheter|Four series of cardiac output measurements, each series consists of eight measurements using cold and eight measurements using tepid injectate. Randomized order of temperature at first series and crossover design.|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Cardiac output, Thermodilution