2.1 CME

Advanced Haemodynamic Monitoring

Speaker: Dr. Gunadhar Padhi

Senior Critical Care Consultant, Apollo Hospitals, Navi Mumbai

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Description

This webinar will focus on modern haemodynamic monitoring techniques used in critically ill patients to guide timely and accurate clinical decisions. Participants will gain insights into assessing cardiac output, fluid responsiveness, and tissue perfusion beyond conventional vital signs. The session will emphasize practical interpretation of monitoring data and its application in optimizing fluid, vasopressor, and inotropic therapy. Real-world clinical scenarios will be discussed to help integrate advanced haemodynamic monitoring into daily critical care practice.

Summary Listen

  • Advanced hemodynamic monitoring builds upon basic clinical tools and parameters, focusing on dynamic parameters rather than static ones. Dynamic monitoring, which includes microstarpolation management and advanced hemodynamic tools like advanced perfusion techniques, is generally superior to static parameters in critical care settings.
  • Cardiac output monitoring tools are central to advanced hemodynamic monitoring and fall into three categories: non-invasive, minimally invasive, and invasive. Non-invasive systems are the safest, offering monitoring without vascular access. Minimally invasive techniques estimate cardiac output through vascular catheters, either central or arterial lines, without traversing the body's compartments. Invasive methods involve catheter insertion through body compartments, providing direct and continuous measurement of various hemodynamic parameters.
  • Non-invasive cardiac output monitoring systems use non-bacterial pulse wave analysis, employing tools like point-of-care ultrasound (focus), Nikom (bio-air test principles), and physio flow (bio-impedance principle). These tools measure cardiac output through vessel pulsatility, blood flow, and Doppler techniques. They are trend indicators, not absolute values, making them useful for patients in the ER or transitioning from ICU to the ward.
  • Minimally invasive techniques employ vascular catheters placed in arterial or central lines. Examples include flow track, pico, and lead co-monitoring systems. The catheters do not traverse the entire body, but provide advanced hemodynamic data.
  • Invasive hemodynamic monitoring necessitates catheter insertion into the body's compartments. It provides direct, continuous measurements of hemodynamic parameters, offering reliability and accuracy, however, the procedure carries risks and potential complications, like complications of vascular access or placement of devices.
  • The PiCCO system requires both an arterial and a central line, calibrated through cold bolus thermodilution technique which is a transpulmonary approach. It provides continuous measurements of cardiac output, stroke volume variation, systemic vascular resistance, and global end-diastolic volume. The accuracy of arterial waveform analysis is dependent on vascular compliance and systemic vascular resistance.
  • Transpulmonary thermodilution (TPPT-3D) technique involves injecting cold saline bolus into the central vein, measuring temperature changes in the arterial line via a thermistor. This method is better for patients with arrhythmias or spontaneous breathing. This also measures preload and lung water, valuable in fluid management for shock patients.
  • Flow Track/Vigileo system requires only an arterial line and doesn't need external calibration. It functions using a proprietary algorithm, providing continuous data on cardiac output, stroke volume, stroke volume variation, and systolic pressure variation.
  • Invasive monitoring tools, like the pulmonary artery catheter (Swan-Ganz catheter), require specialized techniques and are more reliable for direct measurement of chamber pressures. Pulmonary artery catheter monitoring is often favored in postcardiac bypass surgery. They measure pressures in the heart and lungs.
  • Pulmonary thermodilution involves cold saline injection through a pulmonary artery catheter, with temperature change detected by a thermistor. This principle, using Stewart-Hamilton equation, allows calculation of cardiac output, pulmonary artery pressure, pulmonary capillary pressure, and mixed venous oxygen saturation.
  • Mixed venous oxygen saturation indicates the amount of oxygen consumed by peripheral tissues. Values outside the normal range (65-75%) can point to issues with oxygen utilization (e.g., cyanide toxicity, mitochondrial dysfunction) or delivery (e.g., anemia).
  • Pulmonary vascular resistance (PVR), not measurable by many cardiac output monitors, is crucial in heart-lung transplant patients and those with pulmonary hypertension. High PVR puts a load on the right ventricle. Reduction of PVR can be achieved through nitric oxide or selective pulmonary vasodilators.
  • Central venous pressure (CVP) offers insight into volume status, though with limited accuracy. Trends in CVP are more informative than singular measurements. External factors, such as ventilator settings, can influence CVP readings.
  • Guidelines recommend dynamic assessment over static preload markers for fluid responsiveness. While pulmonary artery catheters don't offer mortality benefits in routine ICU cases, they remain useful in select cases like post-cardiac surgery patients and those with pulmonary hypertension.
  • Selecting the appropriate hemodynamic monitoring method depends on factors like complexity of application, risk of complications, need for continuous measurement, and desired accuracy. Use of invasive or calibrated methods is recommended when high accuracy in cardiac output measurement is needed, especially for carogenic shock or complex patients.

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