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Cardiac Output Monitoring. Monica Morosan. Typical value End diastolic volume (EDV)120 ml (65 - 240 ml) End systolic volume (ESV)50 ml(16 - 143 ml) Stroke volume (SV)70 ml (55 - 100 ml) Stroke volume index (33-47 ml/m 2 /beat) Ejection Fraction (Ef)58% (55 to 70%)
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Cardiac Output Monitoring Monica Morosan
Typical value • End diastolic volume (EDV)120 ml (65 - 240 ml) • End systolic volume (ESV)50 ml(16 - 143 ml) • Stroke volume (SV)70 ml (55 - 100 ml) • Stroke volume index (33-47 ml/m2/beat) • Ejection Fraction (Ef)58% (55 to 70%) • Cardiac output (CO)4.9 L/minute (4.0 - 8.0 L/min) • Cardiac index CI (2.6-4.2)L/min/m2 • SVR=80x(MAP-CVP)/CO (800-1200dynes/sec/cm5) • SVRI (1970-2390dynes/sec/cm5/m2)
Cardiac output monitoring • Invasive PA catheter • Non invasive TOE, Echo Oesophageal Doppler Transthoracic impedance Arterial pulse contour analysis (PiCCO) Arterial pulse power analysis (LiDCO)
PA catheter Measures: • Intracardiac pressures • PA pressures • Cardiac output • Oxygen saturation
Indications: IHD, Cardiogenic shock RV failure Septic shock ARDS Periop: high risk cardiac surgery or neurosurgery Contraindications: Tricuspid or pulm valve mechanical prosthesis Right heart mass (Tumour or thrombus) Tricuspid or pulmonary endocarditis
PAOP (PCWP) significance Estimates • Left sided preload • Left ventricular end diastolic pressure • Extravascular lung water • Miocardial O2 consumption
Oesophageal Doppler Measures: Blood flow velocity in the descending aorta CO=VTIxCSAxHR Parameters: CO, SV, FTc, PV (peak velocity), HR CO: 86% agreement between measured CO with Doppler vs PAC
LiDCO • Lithium indicator dilution • Continous, real time pulse power analysis rather than pulse contour • Assumption than pulse power has a linear relationship with flow, uses an algorithm to det CO • Minimally invasive
Safe • Uses the CVP catheter and A line • Injectate 0.15-0.3 mmol Lithium Chloride Contraindications -If already on Lithium -Muscle relaxant drugs -Weight less then 40 kg -First 3 months pregnancy
Pulse contour analysis with intermittent thermodilution measurement Good agreement with PAC Thermistor tipped A line Relies on good A line trace ( arrythmias, AoR, Ao baloon, SVR up): innaacuracies PiCCO
PiCCO • Pulse contour analysis: -Continuous pulse contour cardiac analysis (PCCO) -Arterial blood pressure (AP) -Heart rate (HR) -Stroke volume (SV) -Stroke volume variation (SVV) -Systemic vascular resistance (SVR) -Index of left ventricular contractility • Intermittent thermodilution: • Transpulmonary cardiac output (CO) • Intrathoracic blood volume (ITBV) • Extravascular lung water (EVLW) • Cardiac function index (CFI)
Impedance plethysmography • 2 sets circular wire electrodes around chest and neck • Current passed between outer two( high frec, low magnitude), with measurement of potential difference between the inner two • Maximal rate of change of impedance occurs with peak Ao flow • Movement, arrythmias and diathermy: innacuracies • More evidence in haemodynamically unstable
Thoracic bioreactance NICOM • Modification of impedance technology • To improve the signal to noise ratio • Phase shift in voltage across thorax • 4 electrodes across thorax • CO for L and R side and then averages • Also averages over 60s
Penaz technique • Continous pulse contour analysis of NIBP ( also known as vascular unloading technique) • Finger cuff applies pressure • Infrared light assesses the light absorbtion (artery diameter) • Alters the pressure in the cuff to keep the diameter constant (this pressure=BP) • Trace compared to oscillometric derived systolic and diastolic values • Limitations: oedema or hypeperfusion, low CO, low SVR
Others • Pulse wave transit time: continous, derived from ECG, sats probe trace and Art pressure • Radial artery tonometry • ECHO: LVEF, IVC collapsibility index • All might have a place in low/intermediate risk patients, non-invasive haemodyn optimisation, ED department and diagnostic procedures