Flow Monitoring Approaches Jane Roe Practice Educator (Intensive Care) Adapted by Sarah Leyland (May 2016)

PAC (Pulmonary Artery Catheter) Thursday, 20 September 2018 Approaches & Devices Oesophageal Doppler PAC (Pulmonary Artery Catheter) LiDCO (Lithium Dilution Cardiac Output) SvO2(via PAC), ScvO2 (via CVP) There are more! Jane Roe FCCN 2008

20/09/2018 Pressure, Volume & Flow Combination of all 3 ensure perfusion to all areas Blood pressure Cardiac output or index - flow Stroke volume Preload Afterload Contractility Systemic vascular resistance Frank Starling Law Rosie Maundrill, November 2007

Cardiac Output

DETERMINANTS OF CO Heart Rate Preload Afterload Contractility CVP: Indicates patient‘s heart filling SVV: Preload Responsivness (>13%) (ETT) Afterload SVR: Relaxation / Contraction of arteries. Contractility SV: Power of heart contraction

The PA catheter: the ‘gold standard’ ? Thursday, 20 September 2018 The PA catheter: the ‘gold standard’ ? Dr HJ Swan & Dr W Ganz N Engl J Med (1970) 283: 447-451 Jane Roe FCCN 2008

Where it sits:

What you see as it goes in:

Normal values CO 4-8 L/min SV 60-130 ml PASyst 15-25 mmHg PADiast 6-12 mmHg PAOP 4-12 mmHg SVR 770-1500 PVR 20-120 LVSW 58-104 gm/beat RVSW 8-16 gm/beat DO2 900-1000 mlO2/min VO2 200-290 mlO2/min CI 2.5-4.2 L/min/m2 SVI 30-65 ml/beat/m2 SVRI 1680-2580 PVRI 69-177 LVSWI 50-62 RVSWI 5-10 DO2I 550-650 VO2I 115-160 SvO2 65-75% (Resistance measured in dyne/sec/cm-5) Darovic G (2004) Handbook of Haemodynamic Monitoring Saunders (Elsevier)

Lithium Dilution Cardiac Output (LiDCO) Uses a small dose of Lithium as an indicator to directly measure CO as the device is calibrated. PulseCo uses pulse pressure analysis of the arterial waveform to derive CO, this is adjusted for the individuals physiology when the device is calibrated (autocalibration) Lithium can be injected into peripheral vein via a large bore cannula or CVC

PulseCO Monitor Beat-to-beat changes CO/CI Mean Arterial Pressure SVR & SVRI Stroke Volume Heart Rate DO2 & DO2I

Perfusion / Oxygen Transport A primary function of cardiopulmonary system is to provide sufficient oxygen delivery to maintain normal tissue and organ function O2 Delivery / availability (DO2) The amount (ml) of O2 pumped out by the heart & available to the body per minute O2 Consumption (VO2) The total amount of O2 consumed by the body per minute

Oxygen Delivery (DO2) Consists of: Dependent on: Thursday, 20 September 2018 Oxygen Delivery (DO2) Consists of: Oxygen content of arterial blood (CaO2 = SaO2 x [Hb] x 1.36) WITH The flow of blood leaving the left side of the heart (CO) DO2 = CO x CaO2 Normal DO2 = 900 – 1100 ml/min Normal DO2 I= 520 – 720 ml/min/m2 (indexed value) Dependent on: Pulmonary gas exchange Haemoglobin levels Binding of O2 to haemoglobin Cardiac Output Oxygen delivery or oxygen availability Jane Roe FCCN 2008

Oxygen Delivery to the Cells Thursday, 20 September 2018 Oxygen Delivery to the Cells Gas Exchange Macro Circulation Micro Circulation Cell Function Goal: Optimal Tissue Oxygenation Jane Roe FCCN 2008

Oxygen Consumption (VO2) Consists of: Oxygen content of arterial-to-mixed venous blood (CvO2 = SaO2 - SvO2 x [Hb] x 1.36) WITH The flow of blood leaving the left side of the heart (CO) VO2 = CO x CvO2 Normal VO2 = 200 – 290 ml/min Normal VO2 I = 100 - 180 ml/min/m2 (index value) Function of: The cellular demand of oxygen Adequacy of O2 delivery (DO2) Ability of cell to extract O2 from blood

ScvO2 and SvO2 What? SvO2 = Mixed oxygen saturation, measured in PA ScvO2 = Central venous oxygen, measured in SVC When? SvO2 = used with a PA (Swan-Ganz) catheter ScvO2 = use CVC

SvO2 Monitoring: What is it? In simple terms, it is the oxygen saturation of the blood returning to the right side of the heart. This reflects, in a way, the amount of oxygen “left” after the tissues remove and utilize what they need

ScvO2 How Do We Measure It? Thursday, 20 September 2018 ScvO2 How Do We Measure It? Direct measurement Blood sample from distal lumen of CVC analyzed by a normal blood gas machine Best if IVC for lower body SVC e.g. via jugular) result is upper body Does show trends Jane Roe FCCN 2008

How Do We Measure It? Oximetric Swan (Pulmonary Artery Catheter) Direct measurement Blood sample from distal lumen of pulmonary artery catheter can be analyzed by a normal blood gas machine Used for calibration

Changes in ScvO2 – Possible Clinical Correlations Drop Rise Causes: VO2 DO2 Stress Pain Fever Shivering  PaO2  Hb  Cardiac output  DO2 VO2  PaO2  Hb  Cardiac output Hypothermia Sedation

If your numbers don’t fit your clinical findings… Recheck Recalibrate Rethink

Thursday, 20 September 2018 And… Always use observations in conjunction with “whole patient” observations Trends in observations not “one-off’s” Baseline observations are very important Standardised conditions Accurate & meaningful Appropriate use, not routine or ritualised Understand significance of any change Jane Roe FCCN 2008