Acute Circulatory Failure
Conditions
Keywords
Methylene Blue
Brief summary
International guidelines recommend Methylene Blue (MB) as a second-line drug in the treatment of norepinephrine refractory vasoplegic shock (VS) after Cardiopulmonary Bypass CPB. Macrocirculatory effects of MB in this setting are now well established but microcirculatory effects of MB remain unknown. The purpose of this study is to assess the micro vascular effects of a single administration of methylene blue (1.5 mg/kg over 30 minutes) for norepinephrine-refractory VS post CPB. Microcirculatory effect will be monitored before and one hour after MB infusion through cutaneous refill time, video microscopy measurements of the sublingual microcirculation and tissue oxygen saturation combined with vascular occlusion test (VOT).
Interventions
OTHERHemodynamic assessment (micro and macrocirculatory)
Each of the variable related to macro- and microcirculatory will be evaluated before and one hour after start of MB infusion. Macrocirculatory parameters will include : * Mean, systolic, diastolic arterial, heart rate (HR) * Cardiac output (CO), sequential vascular response (SVR) and stroke volume (obtained with transthoracic echocardiography or transpulmonary thermodilution catheter if available). * A passive leg raising (PLR) test will be performed before and one hour after MB infusion. Patients will be classified as fluid responder if they had a CO of at least 10% after PLR. Microcirculatory parameters will include : * Cutaneous and gingival refill time * Tissue oxygen saturation combined with vascular occlusion test (VOT) * Video microscopy measurements of the sublingual microcirculation * Metabolic variables: Arterial blood gases including arterial lactate and central venous blood gases.
Sponsors
Hospices Civils de Lyon
Study design
Observational model
COHORT
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* patients receiving methylene blue prescribed by the clinician in charge of the patient * patient receiving a dose of norepinephrine \> 0.5µg/kg/min * normal or increase cardiac (\> 2 L.min-1.m-2) at the time of inclusion * vasoplegic syndrome post cardiopulmonary bypass for cardiac surgery
Exclusion criteria
* the need for hemodynamic intervention during the time of study (fluid resuscitation, introduction of inotropic or vasopressor support, change in inotropic support dose) * age under 18 years
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in tissue oxygenation (resaturation speed expressed as %/sec) during the vessel obstruction test. | one hour after the start of methylene blue infusion | The resaturation speed during reperfusion is defined as maximum StO2 - minimum StO2 /time of reperfusion. Tissue oxygen saturation (StO2) will be measured by near-infrared reflectance spectroscopy (NIRS) optode applied to the medial surface of the left or right forearm, 5 cm below the elbow. The sensor will be connected to the four-wavelength O3 Regional Oximetry device (Masimo Incorporation). All StO2 values will be recorded continuously and read every second. Data will be recorded online, transferred to a laptop with a specific software designed by Masimo (Masimo Instrument Configuration Tool (MICT) Version 1.0.4.9), and stored for further analysis. After completion of a baseline set of measurements for each patient, a vascular occlusion test (VOT) will be then perform using a manual pneumatic cuff inflator (Spengler SAS, Antony, France) positioned at the upper extremity of the ipsilateral upper limb. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Video microscopy measurements of the sublingual microcirculation | one hour after the start of methylene blue infusion | Proportion of Perfused Vessel (PPV), Total Vessel Density (TVD), Perfused Vessel Density (PVD), Microcirculatory Flow Index (MFI) and heterogeneity index will be reported. Video microscopy measurements will be collected before and one hour after the beginning of MB infusion. |
| Cutaneous and gingival refill time | one hour after the start of methylene blue infusion | Five consecutive cutaneous recoloration time (CRT) acquisitions on the thorax and five consecutive gingival recoloration time (GRT) acquisitions will be made after calibrated compression of the skin and the gingiva. These measurements will be collected before and one hour after the beginning of MB infusion. |
| Metabolic variables | one hour after the start of methylene blue infusion | Arterial blood gases including arterial lactate and central venous blood gases will be withdrawn before and one hour after the beginning of MB infusion concomitantly to measurement of cardiac output to allow calculation of oxygen delivery (DO2), oxygen uptake (VO2), oxygen extraction ratio (ER), venous-to-arterial difference in carbon dioxide partial pressure (PCO2gap), modified respiratory quotient (RQ modified) and ratio of central venous-to-arterial carbon dioxide content to arteriovenous oxygen content (DavCO2/DavO2). |
Countries
France
Outcome results
None listed