Hemodynamics Hemodynamics The study of forces involved in the flow of blood throughthe cardiovascular and circulatory systems
Components: Blood pressure Central venous pressure Right and left heart pressures
Assessment of ventricular function through evaluation ofhemodynamic variables enables the nurse to identify cardiovascular problems and to determine appropriate interventions
Hemodynamic Monitoring Non-invasive E.g. blood pressure monitoring or mean arterial pressure Invasive Used to make actual measurements of pressures (i.e. directlywithin the heart) Allows the nurse to have access to much more information about the status of the patient But this will never replace hands-on patient assessment
Primary purpose: Early detection, identification and treatment of life-threateningconditions such as heart failure and cardiac tamponade Allow immediate evaluation of patients response to treatment such as drugs and mechanical support
Indications for Hemodynamic Monitoring Signs of severe dehydration, hemorrhage, G.I. bleed
Burns or surgery All types of shock Any deficit or loss of cardiac function (such as AMI orCHF)
Hemodynamic parameters Cardiac Output (CO) The volume of blood ejected from the heart per minute A function of heart rate and stroke volume (CO = HR x SV) Must generate enough pressure in systole to overcome aorticpressure and systemic vascular resistance and eject sufficient blood volume to perfuse the organs of the body Normal value: 4 to 8L/min at rest
Cardiac Index (CI) an adjustment of the cardiac output considers the patients body size (or Body Surface area) Formula: CI = CO / BSA Normal value: 2.5 t0 4 L/min/m2
Hemodynamic parameters Heart Rate (HR) Often overlooked, but very useful and simple Detects cardiac dysrrhythmias, such as bradycardia ortachycardia Normal value (in adult): 60 to 100 beats per minute Heart rate that is more than 120 bpm decreases cardiac outputdue to decreased ventricular filling time
Stroke Volume (SV) Volume of blood ejected with each ventricular contraction In cardiac dysfunction, the SV decline is not immediatelyapparent Formula: SV = CO / HR
Hemodynamic parameters Central Venous Pressure (CVP) A measurement of the right atrium Reflects the right ventricular diastolic pressure, or theability of the right side of the heart to pump blood Used for assessing the relationship between cardiac action, vascularity and blood volume Used for prescribing fluid replacement or restrictions more accurately Normal value: 2 to 6 mmHg Decreased CVP may indicate hypovolemia, neurogenic shockor anaphylactic shock Increased CVP may indicate right ventricular dysfunction, cardiac tamponade, constrictive pericarditis, pulmonary hypertension, tricuspid stenosis or tricuspid regurgitation
Components of Hemodynamic Monitoring Amplifier located inside the bedside monitor;increases the size of signal from the transducer
Recorder or monitor to display the signal and recordinformation
Transducer changes the mechanical energy or thepressures of pulse into electrical energy
Supplemental equipment Pressure tubing prevents tubing distention
Video (CVP)
Nursing considerations Always level and zero the system to ensure accuracy of valuesobtained
Leveling Performed to eliminate the effects of hydrostatic pressure onthe transducer
Should be done before and after connecting the pressuresystem to the patient, with every change in position of the patient and prior to zeroing and calibration
Nursing considerations Always level and zero the system to ensure accuracy of valuesobtained
Zeroing Performed to eliminate the effects of atmospheric pressureon the transducer
Should be performed before and after connecting thepressure system to the patient, with any leveling and whenever there is a significant change in the hemodynamic variables
Nursing considerations All values should be rated at the end of expiration
The catheter must be flushed at least every 8 hours Precaution Follow electrical safety monitoring guidelines Risk to patient: ventricular fibrillation A defibrillator, emergency crash cart and medicationsmust be readily available
Complications Pneumothorax During catheter insertion, the needle may puncturethe apical lung as it passes through the subclavian vein
Constant wedging of the PA catheter The catheter may migrate into smaller pulmonaryvessel resulting in pulmonary ischemia This is an emergency! If this occurs, the catheter balloon must be deflated, and the catheter must be pulled back slightly
Complications Ventricular irritation Occurs when the catheter floats back into the rightventricle or is looped through the ventricle May cause ventricular dysrhythmmias Notify the physician if the catheter needs to be floated back into the pulmonary artery
Complications Air embolism May occur when the balloon ruptures Causes pulmonary embolism When inflating the balloon, feel for resistance andwatch for a dampened waveform. No resistance and no wedge are indications of a ruptured balloon If this happens, remove the syringe, close the port and label the port that the balloon is ruptured
Complications Dampened waveform May be caused by kinks, bubbles within the lines,clots or the catheter may be against the vessel wall
Complications Dampened waveform May be caused by kinks, bubbles within the lines,clots or the catheter may be against the vessel wall
Infection Always observe sterile technique
Complications Infection Always observe sterile technique
