ANESTHESIA FOR MYOCARDIAL REVASCULARIZATION. Alla Klimova, M.D UAMS, Little Rock, AR

Transcription

1 ANESTHESIA FOR MYOCARDIAL REVASCULARIZATION Alla Klimova, M.D UAMS, Little Rock, AR

2

3 Objectives Historical perspective of CABG Stent or surgery Indication for CABG surgery On pump CABG : design and pathophysiology of CPB circuit, myocardial protection. Off pump CABG Robotic CABG Anesthetic management

4 Historical perspective of CABG 1937 Dr.John Gibbon designed heart lung machine 1951 Vineburg implanted internal thoracic artery (IMA) directly into myocardium 1967 Cleveland Clinic began performing saphenous vein CABG 1968 Green performed an anastomosis of IMA directly to coronary artery. In 1990ties enhanced recovery (fast track) and minimally invasive cardiac surgery initiated by economic pressure and latter fueled by recognized improvement in clinical outcome. Transesophageal echocardiography important clinical development

5 Dr. John Gibbon

6 John Gibbon and the heart-lung machine: a personal encounter and his import for cardiovascular surgery Michael E. DeBakey, MD Presented at the symposium, "Gibbon & His Heart-Lung Machine: 50 Years & Beyond," Philadelphia, PA, May 2, Ann Thorac Surg 2003;76:S2188-S2194

7 Present perspective of CABG Percutaneous coronary interventions (PCI) Surgical approach switch from on pump to off pump CABG Development of heart stabilization technique Robotic surgery boom Transesophageal echocardiography Fast tracking management

8 Stent or Surgery study (SOS) 2001 (The Lancet) mortality at 1year additional PCI additional CABG adverse effects PCI and stenting n = % 13% 9% 22.1% CABG n = % 4.8% 1% 12.2%

9 Stent or surgery? Due to repeated treatment, costs for stents and surgery are approximately equal after 2 years Minimally invasive surgeries (MIDCABG) result in fewer complications and shorter hospital stay - this is essentially removing the cost advantage of stenting Diabetics have a substantially better response to CABG than angioplasty or stenting

10 STENT or PCI Isolated proximal single vessel disease Hybrid procedure (1stent +1 graft MIDCABG) Contraindication to CABG Coronary stenosis after cardiac transplantation

11 The 2004 ACC/AHA CABG guidelines: CABG is the preferred treatement for: Disease of the left main coronary artery (LMCA) Disease of all three coronary vessels (LAD, LCX and RCA).

12 The 2005 ACC/AHA CABG guidelines further state: CABG is the likely preferred treatment with other high risk patients such as those with severe ventricular dysfunction (low ejection fraction) or diabetes mellitus.

13 On pump CABG (80% of all CABG) standard conventional classic

14 Cardiopulmonary bypass (CPB) Extracorporeal circulation System to temporarily perform the functions of the heart and lungs Perfusion of the brain and vital organs are maintained during surgery on the non beating heart Ascending aorta is cross-clamped, thus excluding the coronaries from the circuit

15 Venous cannula Patient Arterial cannula Venous reservoir ARTERIAL FILTER Oxygenator Heat exchanger Main pump Roller or Centrifugal

16

17 CARDIOPLEGIA (potassium rich solution stops the heart in diastole) ANTEROGRADE RETROGRADE coronary arteries coronary sinus aortic root myocardial hypertrophy high proximal obstruction

18 Cardioplegia composition KCl diastolic arrest aspartate/glutamate metabolic substrate Glucose metabolic substrate THAM / histidine buffer Mannitol osmolarity CPD free Ca concentration MgCl2 antagonize Ca effect Blood O2 carrying capacity

19 Myocardial O2 consumption Normal working heart: 8 ml O2/100g/min Empty beating heart : 5.6 ml O2/100g/min Kalium arrested heart:1.1ml O2/100g/min Myocardial cooling : 0.3 ml/100g/min

20 CPB as a perfusion system WHAT IS OPTIMAL FLOW? Cardiac output = pump flow rate consider AGE TEMPERATURE DEPTH OF ANESTHESIA L/min/m2

21 CABG procedure is a team work anesthesiologist perfusionist Average team Good communication BETTER OUTCOME!!! surgeon Sky team Bad communication WORSEN OUTCOME!!!

22 Complications of CPB Hemolysis / RBC damage in pump circuit Coagulopathy/ platelets dysfunction, systemic heparinization Microcirculation abnormalities/ lactate, 3th spacing Hemodynamic instability/stunned myocardium,vasoplegia Myocardial depression Pulmonary dysfunction/intersticial edema,microemboli, surfactant Neurological dysfunction/stroke, impaired cognition Hypothermia side effects Systemic inflamatory response

23 WARM CPB New trend to conduct CPB at near normothermic level. Advantage of avoiding cooling and rewarming shortening CPB hazard of overheating hypothermia less bleeding COGNITIVE OUTCOME IS COMPARABLE FOR TEPID AND MODERATELY HYPOTHERMIC CPB MANAGEMENT

24 On pump CABG anesthesia management Cardiac anesthesiologist must induce a patient who would not receive general anesthesia for elective non cardiac surgery.

25 Slow cardiac induction with a least cardiodepresive anesthetics. Betablockers, ACE inhibitors, Statins Fentanyl + Etomidate + nondepolarizing muscle relaxant Atraumatic and fast intubation Close monitoring Prophylactic antibiotics Temperature management TEE

26 Cardioprotection with Volatile Anesthetics: Mechanisms and Clinical Implications Anesthesia & Analgesia, June 2005,Vol.100,(6), Anesthetic Preconditioning, (administration of a volatile anesthetic before the period of myocardial ischemia) resulted in a similar degree of cardioprotection as observed after ischemic preconditioning, both for functional recovery and for protection from ischemic damage to the heart and lungs. In addition to attenuating the effects of ischemia on contractility, anesthetic preconditioning also decreased the area of the myocardium that was affected during ischemia.

27 Pre CPB period 2 stages of stimulations Incision HIGH Sternal split Sternal spread Sympathetic nerve dissection Aortic cannulation Preincision LOW Radial artery harvest Thoracic artery dissection Venous cannulation

28 Pre CPB period (cont.) HEPARINIZATION ACT dose response curve or 300 mg / kg ACT should be > 300 sec Ideally > 480 sec

29 On CPB COFFEE TIME OR OBSERVATION surgical field CVP and MAP Patient s face

30 Post CPB period Inotropic support Vasopressor suport Mechanical ventilation / vaporizer Temperature 36 degree C Adequate heart rate and rhythm / pacer No air in the heart

31 OFF PUMP CABG 10 20% Short vessel patency is equivalent with on pump CABG. Long term patency???

32 Octopus tissue stabilizator (Medtronic)

33 Apical and stabilization device

34 OFF PUMP CABG Classic with sternotomy (for multiple vessels) Minimally Invasive Direct CABG (only LAD) - through left anterior thoracotomy Robotic CABG (computer assisted)

35 Patient s selection (OPCABG) DEPENDS ON SURGEON ELDERLY PATIENTS WITH SEVERE SYSTOLIC DYSFUNCTION, LUNG DISEASE, VASCULAR DISEASE, RENAL DYSFUNCTION AND AT RISK FOR STROKE.

36 MONITORING FOR OPCABG EXTENSIVE Standard ASA monitors + CVL PAC TEE Direct Blood pressure BIS

37 Anesthesia management points classic OPCABG Early extubation and recovery is desired Maintanance of adequate coronary perfusion is a goal (coronary artery is clamped for distal anastomosis) Ischemic and pharmacologic preconditioning Importance of adequate preload and patient s position changes No antifibrinolytic therapy need Lower Heparin requirement

38 Indications for converting to on CPB Persistence of the followings for >15 min despite aggressive therapy: Cardiac index <1.5 litre /min/ m2 SvO2 <60% MAP <50 mm Hg STsegment elevation >2 mv Large new wall motion abnormalities or collapse of LV function assessed by TEE Sustained malignant arrhythmias

39 Roboticaly enhanced CABG off pump 1999 first reported by Loulment and Reichenspurner Anesthetic consideration LIMITED ACCES TO THE PATIENT Need for extensive monitoring External defibrilator pads ON

40

41 Robotic CABG (cont.) Patient s position: 30 degree left side up Deflation of left lung (DLT or bronchial blocker) CO2 insufflations of left hemithorax (8 mmhg) External defibrillator pads applied Careful temperature management (lengthy surgery)

42 Instrumentation Endoscopic Robotic Degree of freedom Tremor filter Motion transmission Hand-eye alignment Fulcrum effect Force ratio 4 NO 1:1 poor Reversed motion large,abnormal non linear 6 YES 1:1 TO 1:5 natural Not effective favorable

43

44 No ideal anesthesia, no ideal surgery exist. Choose for optimal ones.