Hypothermic ventricular fibrillation

Introduction Cary W. Akins Basic principles developed in Most surgeons use hyperkalemic cardioplegic arrest Useful tecnique Akins operated 500 pts, demonstrated low peri op infarction and hospital mortality

Indications and contraindications Successful with revascularisation and LV aneurism No aortic cross clamp: - Redo mitral valve repair - Calcified aorta - Brittle aorta Problematic in AI

Principles VF and no aortic cross clamp Hydraulic argument Root P 80 – 100 mmHg Low P in LV Hypothermia Proximal anastomosis prior to bypass

Principles GA and IV TNT Β blocker post induction Heparin prior to cannulation Proximal anastomosis Mannitol and crystalloid prime 28 – 32 ˚C MAP 80 – 100 mm Hg VF Venting LV No cross clamp Vessel isolation First graft Circumflex warming

Pre operative Regular preparations Akins suggests non ischemic status

Post op Coronary perfusion Diuresis TNT Aspirin

Advantages Less trauma to aorta No retrograde cannula Decreased global myocardial ischemia Grafting in any order Side effects of cardioplegia prevented Pulsatile flow with balloon pump

Disadvantages Partial cross clamp for proximal anastomosis Transient ischemia Local isolation Retraction of heart when doing posterior and lateral anastomosis Blood in field Fibrillating heart more MVO2 Fibrillating heart decreased DO2 High risk with hyper tropic myocardium Air emboli

Operative tecnique Anastomosis as usual Heparin prior to internal mammary A clamp Papaverin Aortic cannulation Check veins 5 grafts (Akins) Proximal anastomosis Avoid calcified areas Side clamp ( check pressure) Proximal anastomosis prior to bypass Venous cannulation 28 – 30 ˚ C - VF

Operative technique Venting Distal anastomosis - Most ischemic area first - Left lat circumflex prior to LAD - Occluded vessels 1 st - Regular technique Remove air prior to tie Warming 34˚C Pacing wires Vent out Weaning