ECMO Treatment, ARDS, Pneumonia, Intensive Care, Hemodynamic Monitoring, Fluid Responsiveness
Conditions
Keywords
VV ECMO, Extracorporeal Membrane Oxygenation, ARDS, Intensive Care Medicine, Critical Care Medicine, Hemodynamic Monitoring, Fluid Responsiveness, Passive Leg Raising, Pulse Contour Analysis, Transpulmonary Thermodilution, Bioreactance, Pulse Pressure Variation, End-expiratory Occlusion Test, End-inspiratory Occlusion Test, Cardiac Output, LVOT VTI, Stroke Volume, Vena Cava Ultrasound
Brief summary
In extracorporeal membrane oxygenation (ECMO), blood is drawn out of the body via tubes, oxygenated in an artificial lung; and then pumped back into the blood vessels. This allows the supply of oxygen-rich blood to the organs (brain, heart, lungs, kidneys, liver, intestines, etc.) to be maintained. Continuous monitoring of cardiac function and circulatory status (blood pressure, blood flow to organs) is very important in intensive care medicine in order to control the administration of circulation-supporting medication and infusions. Various devices are routinely used for this task. However, in the specific situation of ECMO treatment, the measurements of these devices could be affected due to the artificial circulation; outside the body. The purpose of this study is therefore to test the accuracy of different methods of circulation monitoring during ECMO treatment.
Detailed description
Hemodynamic monitoring and tests for fluid responsiveness are cornerstones of intensive care medicine. Generally, hemodynamic measurements can be obtained, for instance, with the following methods: pulmonary artery catheter, transthoracic echocardiography (TTE), esophageal doppler, transpulmonary thermodilution, pulse contour analysis and bioreactance, amongst others. Maneuvers for assessing volume responsiveness include passive leg raising (PLR), respiratory pulse pressure variation (PPV), stroke volume variation (SVV), inferior vena cava ultrasound (IVC), and end-inspiratory or end-expiratory occlusion tests. While these commonly used methods of hemodynamic assessment have been validated in various clinical scenarios, data are lacking in the setting of venovenous extracorporeal membrane oxygenation (VV ECMO). VV ECMO is commonly used for respiratory support in patients with severe acute respiratory failure. Blood is usually drained from a femoral vein, pumped through an oxygenator, where it is oxygenated and decarboxylated, and thereafter reinfused into the patient via a central venous, most commonly jugular, return cannula. Theoretically, the artificial circulation with its blood drainage and return flows may interfere with common hemodynamic monitoring techniques and lead to erroneous measurements. The aim of this study therefore is to validate select techniques of hemodynamic monitoring and assessment of fluid responsiveness in patients on VV ECMO. In the context of this study, the performance of different hemodynamic monitoring tools and techniques for predicting fluid responsiveness will be compared.
Interventions
DEVICETransthoracic Echocardiography
Transthoracic echocardiography (TTE) is used for intermittent non-invasive stroke volume (SV) measurements. It is calculated by multiplication of left ventricular out flow tract (LVOT) and LVOT velocity time integral (VTI), obtained in a parasternal long axis view and apical five chamber view, respectively.
Pulse Contour Analysis allows an automated and continuous measurement of stroke volume (SV). Its underlying principle is that the integral of the systolic arterial pressure curve directly correlates with stroke volume.
Transpulmonary thermodilution (TPTD) involves the administration of a cold saline bolus into a central venous catheter. A special thermistor catheter placed in the femoral or brachial artery detects the successive changes in blood temperature. The resulting heat dissipation curve is analyzed to estimate stroke volume, cardiac output and other hemodynamic variables such as intrathoracic thermal volume (ITTV), pulmonary thermal volume (PTV), global end-diastolic volume (GEDV), intrathoracic blood volume (ITBV) and extravascular lung water (EVLW). Intermittent TPTD-derived cardiac output measurements (typically performed 1-3x/d) are used to calibrate pulse contour analysis.
DEVICEEsophageal Doppler
In esophageal Doppler, a thin ultrasound probe, coated with aqueous ultrasound gel, is orally or nasally inserted into the esophagus and orientated towards the aorta. By emission and detection of continuous wave Doppler signals, real time spectral waveforms of red blood cell velocity in the aorta are obtained, from which cardiac indices can be derived.
DEVICEBioreactance
Bioreactance is a noninvasive hemodynamic monitoring technique, in which four double electrode sensors are placed on the skin of the chest. A high frequency sine wave is transmitted across the thorax. Pulsatile flow in the aorta causes phase shifts and amplitude changes of this signal, which are measured across the different electrodes and used to compute cardiac output.
DIAGNOSTIC_TESTPassive Leg Raising
Passive Leg Raising (PLR) is a maneuver that mimics a fluid challenge by shifting about 300 ml of venous blood from the lower body to the heart. Thereby, it can help to predict fluid responsiveness without actual fluid infusion. To start with, the patient is placed in a semi-recumbent position. Then, the bed is adjusted so that the patient's torso is moved to a horizontal position and the lower limbs are raised to an angle of 45°. Hemodynamic effects occur and can be measured within one minute.
DIAGNOSTIC_TESTVena Cava Ultrasound
Inferior Vena Cava (IVC) Ultrasound has become a popular technique for assessing volume status. IVC diameter is measured in a subcostal long-axis IVC view 1-2 cm from the junction with the right atrium. The magnitude of distensibility during mechanical ventilation cycles or collapsibility during spontaneous breathing has been proposed to correlate with fluid responsiveness
DIAGNOSTIC_TESTEnd-expiratory /-inspiratory occlusion test
In preload-dependent patients, mechanical ventilation induces periodic changes in cardiac output. Standardized maneuvers of end-expiratory or end-inspiratory interruption over 15 seconds may increase or decrease stroke volume, respectively, which is a valid predictor of fluid responsiveness
DRUGFluid bolus
To verify fluid responsiveness, 500 ml of balanced crystalloids will be infused over a time of 15-20 min (25-33.33 ml/min) after completion of passive leg raising and restoration of baseline patient positioning.
Sponsors
Medical University of Vienna
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
DIAGNOSTIC
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to 75 Years
Healthy volunteers
No
Inclusion criteria
* Patient receiving VV-ECMO support * Age 18 - 75 years
Exclusion criteria
* Pregnancy * Conditions not allowing for passive leg raising maneuvers, e.g. open abdomen, known or suspected elevation of intracranial pressure, recent leg or spinal trauma or orthopedic conditions not permitting leg raising * Known ischemic or hemorrhagic stroke within 3 months prior to study enrollment. Suspicion of raised intracranial pressure is defined as pupil divergence (if not yet further clarified radiographically/neurologically/ophthalmologically) or signs detected in routine computed tomography scans (compressed or elapsed basal cisterns or midline shift > 5 mm.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Agreement of receiver operating characteristic (ROC) curves for predicting fluid responsiveness using the passive leg-raising test between different cardiac output measurement techniques (echocardiography, pulse contour analysis, thermodilution). | Repeated measurements throughout ECMO therapy (duration ranging from a few days to up to 24 weeks) and within up to 7 days after ECMO removal. Separate analysis for controlled and assisted mechanical ventilation. | Cardiac Output (L/min) will be measured using transthoracic echocardiography, uncalibrated pulse contour analysis, and thermodilution before, during, and after a passive leg-raising test, as well as after administration of a fluid bolus of 500 ml balanced crystalloids over 15-20 min. A cardiac output increase of \> 15% will be the cut-off for defining fluid responsiveness. Receiver operating characteristic (ROC) curves will be generated for each cardiac output measurement technique and compared using the Hanley-McNeil method. The agreement between the ROC curves (Hanley-McNeil test statistic) will serve as the primary outcome. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Diagnostic performance (receiver operating characteristic (ROC) area under the curve) of an inspiratory and expiratory occlusion test in conjunction with pulse contour analysis for the prediction of fluid responsiveness during ECMO. | Repeated measurements throughout ECMO therapy (duration ranging from a few days to several weeks) and within a few days after ECMO removal. Separate analysis for controlled and assisted mechanical ventilation. | Cardiac Output (L/min) will be measured using calibrated and uncalibrated pulse contour analysis before, during, and after an end-inspiratory and end-expiratory occlusion test (15 s), as well as after administration of a fluid bolus of 500 ml balanced crystalloids over 15-20 min. A cardiac output increase of \> 15% after fluid infusion will be the cut-off for defining fluid responsiveness. Receiver operating characteristic (ROC) curves will be generated to assess the performance of the end-inspiratory and end-expiratory occlusion tests and the best threshold for predicting fluid responsiveness during ECMO. |
| Changes of cardiac output (L/min) over the course of ECMO therapy | Repeated measurements throughout ECMO therapy (duration ranging from a few days to up to 24 weeks) and within up to 7 days after ECMO removal. | Cardiac output (L/min) will be measured at different time points (at least at the beginning of ECMO therapy and after ECMO removal) throughout ECMO therapy using transthoracic echocardiography, uncalibrated pulse contour analysis, and thermodilution. |
| Changes of tricuspid annular plane systolic excursion (TAPSE, mm) over the course of ECMO therapy | Repeated measurements throughout ECMO therapy (duration ranging from a few days to up to 24 weeks) and within up to 7 days after ECMO removal. | Tricuspid annular plane systolic excursion (TAPSE, mm) will be measured at different time points (at least at the beginning of ECMO therapy and after ECMO removal) throughout ECMO therapy using transthoracic echocardiography. |
| Changes of tissue doppler imaging tricuspid annular velocity (cm/s) over the course of ECMO therapy | Repeated measurements throughout ECMO therapy (duration ranging from a few days to up to 24 weeks) and within up to 7 days after ECMO removal. | Tissue doppler imaging tricuspid annular velocity (cm/s) will be measured at different time points (at least at the beginning of ECMO therapy and after ECMO removal) throughout ECMO therapy using transthoracic echocardiography. |
| Changes in cardiac output (L/min, measured by transthoracic echocardiography, uncalibrated pulse contour analysis, thermodilution) at different ECMO blood flow rates | A few days (up to 5 days) before the expected ECMO removal: during ECMO weaning trial, i.e. zero ECMO gas flow | During the ECMO weaning trial (zero gas flow), cardiac output (L/min) will be measured repeatedly at different ECMO blood flow rates (1 l/min, 3 l/min, 5 l/min or maximum flow with venous pressure \<-100 mmHg) using transthoracic echocardiography, uncalibrated pulse contour analysis, and thermodilution. |
Countries
Austria
Contacts
Primary ContactBernhard Nagler, MD
Backup ContactThomas Staudinger, MD
Outcome results
None listed