CVS Monitoring in Shock

CVS Monitoring Non-invasive techniques: Invasive Monitoring: Clinical assessment of tissue perfusion ECG, NiBP, pulse oximetry; Non-invasive CO studies – Echo, NiCO method Invasive Monitoring: Central venous pressure monitoring; Direct arterial line pressure monitoring; Cardiac Output studies (Pulmonary Artery Catheter) 2

Central Venous Catheterisation Internal jugular vein Subclavian vein Axillary vein Femoral vein The absolute value is often unhelpful, except in extreme cases of severe hypovolaemia, significant fluid overload, or heart failure. Correct interpretation requires assessment of the change in central venous pressure in response to a fluid challenge in conjunction with alterations in other monitored variables. Other Indications for CVC: Drug delivery (Adrenaline, Noradrenaline, Potassium, other hypertonic solutions), Total Parenteral Nutrition (TPN), etc. 3

Complications of central catheters On insertion Cardiac arrythmias Pneumothorax / haemothorax Air embolism Surrounding tissue injuries Cardiac tamponade Post insertion Infection (consider removal after 7 days) Cardiac arrhythmias Displacement of catheter Blockage of lumen(s) Air / material embolism Thrombus formation 4

Direct arterial pressure monitoring Invasive cannulation of an artery for continuous monitoring of direct BP; used in: Haemodynamically unstable patient, patient in shock Patient receiving inotropic / vasoactive agents For blood sampling (ABG’s, U&E’S, glucose etc) Patient with physiological difficulties for NIBP (obesity, AF) Stroke volume variation (SVV) : difference between the largest and the smallest arterial wave traces during respiratory cycle 5

SPV and PVI In spontaneous (negative pressure) breaths, pulmonary vessels dilated and fill with blood, so less gets to left side of heart 6

Techniques to assess cardiac output (Flow-based techniques) Oesophageal Doppler based on determination of RBC velocity/flow Trans-oesophageal Echocardiography (TOE) Gold standard in USA Arterial pulse/pressure wave analysis (PPWA) eg PiCCO, Vigileo, LiDCO Combination of pulse/pressure wave analysis (PPAW) with oesophageal Dopler flow measurement (for re calibration) Bioimpedance / Bioreactance Change in amplitude / frequency of a transmitted electrical signal 7

Oesophageal Doppler

Pulse contour analysis PPWA If an arterial pressure waveform is calibrated to a known cardiac output then tracking the changed in the shape and size of arterial waveform can give information to the changes in cardiac output.

Pulmonary artery catheterisation Dr. Jeremy Swan and Dr. William Ganz Developed 1971 Catheterisation of the pulmonary artery with a balloon flotation catheter allows to measure: Preload - indirect assessment of the filling pressure of the left ventricle (pulmonary artery occlusion or wedge pressure) Contractility – by using ‘thermodilution’ technique Afterload or SVR - by calculating from the formula SVR = CO / MAP (PAC; PAFC; PAOP; PAWP) 10

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