Determination of left ventricular stroke volume from the arterial pressure wave

Transcription

1 Integrative Human Cardiovascular Control The Panum Institute/ Rigshospitalet, University of Copenhagen May 2018 Determination of left ventricular stroke volume from the arterial pressure wave Jo(Han)nes van Lieshout Academic Medical Centre, University of Amsterdam NL School of Life Sciences, University of Nottingham UK

2 Outline - Continuous stroke volume / beat-to-beat cardiac output Arterial pressure Features Pulse Contour and Modeling Evaluation of continuous Stroke Volume Arterial pressure and the Circulatory State Machine learning in Cardiovascular Monitoring

3 Outline - Continuous stroke volume / beat-to-beat cardiac output Arterial pressure - Features

4 dois (1872) hollow needle of a syringe stuck into an artery of a dog a paper strip moved where blood droplets hit the table t blood pressure oscillation r published

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6 70s: Non-Invasive Blood pressure Device (NIBD) re oscillations measured by a transducer and inputted microprocessor

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9 Clinical standard

10 rmation from blood pressure wave nformation other than systolic /diastolic ressure is being discarded o analysis over time ntegrating information is complex

11 d Pressure Continuous versus Intermittent S=116 mmhg DIA = 78 mmhg No Blood loss a Blood loss

12 Arterial pressure - Features

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14 Blood Pressure Monitoring Aortic pressure Brachial pressure Radial pressure Finger pressure

15 en providing arterial blood pressure data eport BP Method and Anatomical Site

16 Pressure and Flow Wave from Central to Periphery

17 Outline - Continuous stroke volume / beat-to-beat cardiac output Arterial pressure Features Pulse Contour and Modeling

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19 Impedance easure of opposition to an alternating current (AC) AC Total Peripheral Resistance: MAP / CO DC (direct current)

20 Ascending Aortic Input Impedance hree element model of aortic input impedance ajor properties of aorta and arterial system

21 Aortic Input Impedance haracteristic impedance rterial compliance ystemic (total peripheral) vascular resistance

22 Aortic Input Impedance edance (Z) e opposition that an electronic component, circuit, r system offers to AC and/or DC DC - Direct Current AC - Alternating Current

23 Characteristic Impedance describes the relation between pulsatile flow and pressure at the entrance of the aorta

24 Characteristic Impedance traction of left ventricle ejection of d into aorta a contains already blood existing tic pressure opposes LV outflow elerated blood volume aortic ssure rises

25 Arterial Compliance ection of blood into the aorta the rta expands elastically aortic essure rises creased pressure opposes further flow into the aorta until left ntricular pressure also rises

26 Pump based on Windkessel principle

27 Peripheral Vascular Resistance asure for the ease of constant blood inage from the Windkessel into the ripheral vascular beds mension: pressure / flow ripheral vascular resistance is not a major determinant of

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29 Windkessel

30 Outline - Continuous stroke volume / beat-to-beat cardiac output Arterial pressure Features Pulse Contour and Modeling Evaluation of continuous Stroke Volume

31 Beat-to-beat SV: Ultrasound Doppler (bold) and Modelflow (thin) 150 Valsalva ABP (mmhg) SV (%) Time (s)

32 Thermodilution vs. Modelflow SV from Finger Pressure

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34 Thermodilution vs. Modelflow CO (Orthostatic stress)

35 tandard Cardiac Output Measurement Techniques Techniques like Fick, thermo-dilution and rebreathing have in common o values obtained are averages over at least 20 seconds up to minutes o the cardiac output they reflect is actual under steady state conditions only o comparisons are based on averaging procedures in steady-state condition

36 Thermodilution vs. Modelflow Cardiac Output in Septic Shock 200 Norepinephrine Dopamine Norepinephrine IAP (mm Hg) HR (bpm) CO (l/min) Time (min)

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39 Outline - Continuous stroke volume / beat-to-beat cardiac output Arterial pressure Features Pulse Contour and Modeling Evaluation of continuous Stroke Volume Arterial pressure and the Circulatory State

40 ood Pressure Information on Circulatory State 51 yr, 2 days abdominal discomport ission First Aid Department throwing up blood

41 #1 #2 measurement # 1: BP 130/78 mmhg measurement # 2: BP 126/75 mmhg

42 #1 #2

43 Following infusion of 2 l NaCl 0.9 % in 20 min

44 Blood Pressure and Circulation BP = CO * SVR Blood pressure is the controlled variable Loss of ~ 1 litre of blood or fluid: hardly if any change in blood pressure Blood pressure imprecise parameter for the circulatory filling state

45 Outline - Continuous stroke volume / beat-to-beat cardiac output Arterial pressure Features Pulse Contour and Modeling Evaluation of continuous Stroke Volume Arterial pressure and the Circulatory State Machine learning in Cardiovascular Monitoring

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49 Methods Protocol

50 Progression to syncope

51 Approach Features P SYS MAP P DIA

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54 etermination of Left Ventricular Stroke Volume - Summary ite of measurement and technique determine blood pressure data eporting arterial pressure without knowledge on systemic flow rovides limited information on the circulation onsider one or two continuous SV / CO methods and get trained