Hypothermic ventricular fibrillation

1
Hypothermic ventricular fibrillation

2
Introduction

• Cary W. Akins
• Basic principles developed in 1960 - 1970
• Most surgeons use hyperkalemic cardioplegic
  arrest
• Useful tecnique
• 1984 - Akins operated 500 pts, demonstrated low
  peri op infarction and hospital mortality

3
Indications and contraindications

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

4
Principles

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

5
Principles

• GA and IV TNT
• ? 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

6
Pre operative

• Regular preparations
• Akins suggests non ischemic status

7
Post op

• Coronary perfusion
• Diuresis
• TNT
• Aspirin

8
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

9
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

10
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

11
Operative technique

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