Summary
Highlights
Pico stands for Pulse Contour Cardiac Output, an advanced hemodynamic device. It helps determine if a patient needs fluids or vasoactive therapy, such as vasopressors or inotropes.
Thermodilution involves injecting 10-15 milliliters of cold normal saline through a CVP catheter. A thermistor measures the temperature difference between the CVP and the art line. A higher temperature difference indicates a lower cardiac output, as it takes longer for low cardiac output to circulate. This shows an inverse relationship: low cardiac output means high-temperature difference, and vice-versa.
Thermodilution determines several parameters: Cardiac Output (5-8 L/min), Cardiac Index (2.5-4 L/min/m²), Global End-Diastolic Index (680-800 ml/m²), Intrathoracic Lung Volume Index (850-1000 ml/m²), Extravascular Lung Water Index (3-7 ml/kg), Pulmonary Vascular Permeability Index (1-3 for cardiogenic, >3 for non-cardiogenic pulmonary edema), Cardiac Function Index (4.5-6.5%), and Global Ejection Fraction (25-35%).
Pulse contour analysis estimates cardiac output based on the arterial waveform. When the aortic valve opens, pressure rises, forming a systolic peak. The dicrotic notch occurs when the aorta closes. The area under the curve determines cardiac output.
This principle determines Cardiac Output, Arterial Blood Pressure (120/80 mmHg), Heart Rate (60-100 beats/min), Stroke Volume (60-110 ml), Pulse Pressure Variation (<10%), and Systemic Vascular Resistance Index (1700-2400 dynes·s·cm⁻⁵).