Ventricular Assist Devices

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Dr Priya Nair is a senior intensive care specialist at Sydney's St Vincent's Hospital and an expert in managing patients with cardiac assist devices. In this talk she takes us through the key issues encountered when on managing patients with left ventricular assist devices. As LVADs are becoming more widespread, this inside know-how is invaluable to all of us. They physiology and technology involved with these devices is pretty amazing.

This is the second of two talks at the recent Sydney Intensive Network Meeting. The first talk was by Cardiologist Chris Hayward here.

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Ventricular Assist Devices

  1. 1. Ventricular Assist Devices Peri-operative Care Approach to Emergencies Priya Nair Intensive Care Unit
  2. 2. Immediate Pre-operative considerations
  3. 3. Haemodynamic optimisation • • • • Comprehensive assessment of RV function Pulmonary artery catheter CVP<15 Lowering PVR to optimise right heart function, reduce RAP & hepatic congestion • Aggressively managing volume to minimise RV workload • Inotropes, vasodilators +/- IABP • V-A ECMO as bridge to decision
  4. 4. • • • • • • Renal Function Hepatic Function Nutrition Infection Coagulation status Neurologic, psychosocial & psychiatric Slaughter M et al, Clinical management of continuous flow LVADs in advanced heart failure. Journal of Heart & Lung Transplantation, Vol 29, No 4S, April 2010.
  5. 5. Intraoperative issues
  6. 6. TOE assessment • • • • • • PFO/septal abnormalities Aortic Incompetence- may be under-estimated Mitral Stenosis LV Thrombus Ascending Aorta ?TV annuloplasty • Chumnanvej S et al, Echocardiography for VAD implantation Anesth Analg 2007;105(583-601) • Scalia GM et al, Clinical utility of echocardiography in the management of implantable ventricular assist devices. J Am Soc Echocardiogr 2000;13
  7. 7. PFO/ septal abnormalities
  8. 8. Aortic Reguritation
  9. 9. LV thrombus
  10. 10. Aortic atheroma
  11. 11. Tricuspid Regurgitation
  12. 12. Inflow cannula orientation
  13. 13. Chumnanvej S et al, Echocardiography for VAD implantation Anesth Analg 2007;105(583-601)
  14. 14. Pump placement - pre
  15. 15. Pump placement - post
  16. 16. Inflow & Outflow Doppler Chumnanvej S et al, Echocardiography for VAD implantation Anesth Analg 2007;105(583-601)
  17. 17. Chumnanvej S et al, Echocardiography for VAD implantation Anesth Analg 2007;105(583-601)
  18. 18. Determinants of Flow
  19. 19. Speed adjustment • • • • MAP>65 mm Hg, Midline interventricular septum position Intermittent aortic valve opening No more than mild MR
  20. 20. Chumnanvej S et al, Echocardiography for VAD implantation Anesth Analg 2007;105:583-601
  21. 21. Right-sided circulation • • • • • High capacitance Low –pressure Short isovolumic contraction time Near-continuous systolic ejection period Less tolerant to afterload changes
  22. 22. Response to RV & LV to experimental changes in afterload MacNee et al, AJRCCM 1994
  23. 23. • Lower sarcomere Ca++ concentrations with reduced maximal shortening • Less Ca++ sensitivity during inotropic stimulation • Compromises rapidly leading to hepatic dysfunction & coagulopathy • Increases peri-op mortality from 10-15% to 38-43%
  24. 24. • Peri-op- TX-A2, TNF-α, Interleukin & catechol release during CPB, blood products, inadequate cardioprotection, vasoconstrictors can trigger RVF • LVAD adds to this – shifts inter-ventricular septum to left, – distorts TV lead to TR – improved CO & sudden increase in venous return
  25. 25. Management of RV dysfunction • • • • • • • • Meticulous haemostasis/ avoid blood products Avoid excess RV preload, diuretics Decrease RV afterload- iNO, Iloprost Inotropes- Adrenaline, Milrinone, Dobutamine Vasoconstrictors- to maintain perfusion pressure Pacing Decrease pump speed Consider RCA bypass &/or TV annuloplasty • V-PA ECMO
  26. 26. Immediate post-op ICU care
  27. 27. • • • • • Fluids/inotropes Suction events RV dysfunction Bleeding & anticoagulation Tamponade
  28. 28. Suction event Mauermann W J et al. Anesth Analg 2008;107:791-792
  29. 29. Cyclical LVAD suction Speed (RPM) Flow (L/min) 6 5 4 3 Positive pressure ventilation 2 PEEP 18cmH2O 2800 2700 2600 75 85 Time (seconds) 95
  30. 30. Fischer L et al Management of pulmonary hypertension Anesth Analg 2003;96:1603–16 Day/Month/Year Footnote to go here Page 39
  31. 31. Pericardial collection
  32. 32. V-PA ECMO
  33. 33. Weaning from V-PA ECMO
  34. 34. Take home messages • • • • • • Pre-op haemodynamic optimisation Meticulous care of the RV Avoid over-pumping Serial echocardiography is vital Cautious anticoagulation VADs are preload dependent & afterload sensitive • Mortality and persistent heart failure determined by inefficient unloading of left side and persistent RV dysfunction
  35. 35. At discharge • Comprehensive education of patient & NOK • Easy contact with VAD coordinator & hospital team • Spare controller & battery packs • Strict BP control
  36. 36. Emergency Department presentations • EMS guide January 2012, Mechanical Circulatory Support Organisation • www.jems.com • emcrit.org/wee/left-ventricular-assist-devices-lvads • heartware.org • mylvad.com
  37. 37. Call VAD centre
  38. 38. Check with NOK
  39. 39. • Bleeding – Anticoagulation-related – Abnormal von Willebrand factor • Infection – Driveline – Pump pocket
  40. 40. VAD emergencies Patient in Extremis
  41. 41. 1) AUSCULTATE FOR PUMP HUM
  42. 42. NO HUM • Check cables and connections • Check batteries
  43. 43. 2) CHECK MAP, ASSESS PERFUSION
  44. 44. 3) JUDICIOUS FLUID CHALLENGE • Check pump flows and response. <65mmHg- Adrenaline/Noradrenaline/Vasopressin >65mmHg- Dobutamine/Milrinone • Early arterial line with ultrasound guidance • Care with CVC if RVAD in place
  45. 45. 4)MONITOR +/- DEFIBRILLATE • Check electrolytes, correct potassium • Avoid chest compressions
  46. 46. 5) URGENT ECHO • RV small- hypovolaemia, bleeding, sepsis • RV bigger than LV, D-shaped septum, TR- RV dysfunction • Large LV (+MR)• High power- pump thrombosis (haemolysis, altered hum) • Low power- inflow or outflow obstruction • Ischaemic events • Aortic Incompetence
  47. 47. AT ALL TIMES, BE GENTLE WITH THE RV
  48. 48. Pump flows & MAP OKLikely neurologic event
  49. 49. In short… • • • • • • • Call VAD centre Check connections & cables Auscultate for pump hum/doppler pulse Check doppler BP, perfusion Judicious fluid challenge, inotropes/pressors Echo if possible Consider non-VAD causes for presentation
  50. 50. Questions?

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