Can Capillary Refill Time Variation During Passive Leg Raising Predict Fluid Responsiveness

Study Overview
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Brief Summary
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Fluid responsiveness in a context of circulatory failure can be assessed by different way. Microcirculatory evaluation to assess fluid responsiveness could be interesting, but the available device are expensive and the analysis are delayed. Capillary refill time (CRT) is hampered by its variability. The investigators have developed a method to standardize the pressure, the length of compression and a computerized analysis to calculate the capillary refill time. This method enables accurate measure of CRT. The investigators will study if CRT variation induced by a passive leg raising (PLR) can predict CRT after a 500 ml Fluid Load. About thirty patients in circulatory failure with a continuous cardiac output monitoring for whom, the attending physician has decided a fluid load, will be included. hemodynamic parameters (arterial pressure, venous pressure, cardiac output), metabolic parameters (arterial and venous blood gas and lactate), microcirculatory parameters (assessed by sublingual video-microscopy) and capillary refill time measured on the thorax and on the gingival area will be recorded. Data collection will be made before and after a passive leg raising and after a 500 ml fluid load of crystalloids. Patients will be aposteriori sorted in two groups: responders and non responders, defined by the reduction of CRT after the fluid load. The diagnosis ability of the CRT variation after PLR to predict in which group each patient is classified will be investigate and receiver operative characteristic curve will be built. These results will be compared to the metabolic response, the macrocirculatory response, and the microcirculatory response.

Official Title
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Can Capillary Refill Time Variation Induced by Passive Leg Raising Predict Capillary Refill Time Variation After a Fluid Load in Patients With Circulatory Failure.

Conditions
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Circulatory Failure

Intervention / Treatment
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* Other: Observational study: No special intervention will be made.


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: The patient is equipped with an arterial and a central venous catheter Capillary refill time is measurable. A cardiac output monitoring is available A 500 ml fluid load as been prescribed by the intensivist in charge. A circulatory failure is present defined as follow: Patient treated with inotropic or vasoconstrictive drugs OR Patient presenting an hypotension defined by systolic arterial pressure less than 90 mmHg or mean arterial pressure less than 70 mmHg or a drop 40 mmHg in case of previous Hypertension. WITH tissue hypoperfusion defined by at least one of the following item: Lactate > 1 mmol/L Capillary refill time > 3 s Blotch Organ dysfunction due to the circulatory failure (oligo anuria, acute lung injury / acute respiratory distress syndrome, encephalopathy) Exclusion Criteria: Pregnant woman Cardiogenic pulmonary edema Circulatory support : extracorporal life support / extracorporal membrane oxygenator, Thoratec, heart mate. Moribund patient Intra-abdominal hypertension Lower limb amputation

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

| Intervention/Treatment |
| --- |
|Other: Observational study: No special intervention will be made.|No special intervention will be made, only data will be collected before, and after a passive leg raising and a fluid challenge decided and performed by the attending physician.|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Capillary refill time response | A reduction of about 30% of the capillary refill time after a 500 ml fluid load will defined responders. Evaluation of the diagnosis capacity of capillary refill time variation after passive leg raising to diagnose responders will be investigate. | The period of inclusion last 45 minutes, the outcome will be assessed at the end of the 500 ml fluid load 45 minutes after the inclusion. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Cardiac output response. | An increase of 15% of cardiac output after a 500 ml fluid load will define macrocirculatory responders. Evaluation of the diagnosis capacity of capillary refill time after passive leg raising to diagnose macrocirculatory responders will be investigate. | The period of inclusion last 45 minutes, the outcome will be assessed at the end of the 500 ml fluid load 45 minutes after the inclusion. | 
| Microcirculatory response | An increase of 15% of the proportion of perfused vessels or from 0.6 of the microcirculatory flow index assessed by videomicroscopy after a 500 ml fluid load will define microcirculatory responders. Evaluation of the diagnosis capacity of capillary refill time variation after passive leg raising to diagnose microcirculatory responders will be investigate. | The period of inclusion last 45 minutes, the outcome will be assessed at the end of the 500 ml fluid load 45 minutes after the inclusion. | 
| Metabolic response | An increase of 15% Oxygen consumption after a 500 ml fluid load will define metabolic responders. Evaluation of the diagnosis capacity of capillary refill time to diagnose metabolic responders after passive leg raising will be investigate. | The period of inclusion last 45 minutes, the outcome will be assessed at the end of the 500 ml fluid load 45 minutes after the inclusion. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Fluid responsiveness, capillary refill time, microcirculation, circulatory failure, passive leg raising