Defibrillators Defibrillators Vince Baier Corey Provencher Adam - - PowerPoint PPT Presentation

EM Field Theory Applied: EM Field Theory Applied:

Defibrillators Defibrillators

Vince Baier Corey Provencher Adam Spirer Kory Williams

History History

• First Demonstration; 1899, Prevost and

First Demonstration; 1899, Prevost and Batelli Batelli, Physiologists from , Physiologists from Switzerland. Switzerland.

• Small charges cause ventricular fibrillation

Small charges cause ventricular fibrillation

• Large charges reverse the syndrome.

Large charges reverse the syndrome.

• Claude Beck, 1947, Western Reserve University

Claude Beck, 1947, Western Reserve University ‘ ‘Heart too good to die Heart too good to die” ”

• 14 Year Old Boy saved from congenital heart disease by

14 Year Old Boy saved from congenital heart disease by defibrillation with procaine amide heart medicine. defibrillation with procaine amide heart medicine.

• AC Current 110

AC Current 110-

• 240 V

240 V → →300 300-

• 1000 V

1000 V; Damage to Cells; Bulky ; Damage to Cells; Bulky Transformers Transformers

• Dr V.

Dr V. Eskin Eskin and A. and A. Klimov Klimov in Frunze , USSR 1950 in Frunze , USSR 1950’ ’s; Closed Chest s; Closed Chest Method; AC >1000V Method; AC >1000V

History History

• Bernard

Bernard Lown Lown; 1959 DC Capacitors to achieve ~1000V (Approx. ; 1959 DC Capacitors to achieve ~1000V (Approx. 100 100-

• 200 Joules)

200 Joules)

• Charge through an inductance to produce heavily damped

Charge through an inductance to produce heavily damped sinusoidal wave; sinusoidal wave; Lown Lown Waveform Waveform

• 1980

1980’ ’s BTE Lower Energy, Weight Reduction s BTE Lower Energy, Weight Reduction

• Modern Machines: BTE with Automatic measurement of

Modern Machines: BTE with Automatic measurement of transthoracic transthoracic impedance impedance

• Frank

Frank Pantridge Pantridge, Belfast , Belfast; Portable Machines ; Portable Machines

• Stephen

Stephen Heilman Heilman, , Alois Alois Langer, Morton Mower, Langer, Morton Mower, Michel Michel Mirowski Mirowski, , and and Mir Mir Imran Imran; ICD ; ICD

• February 1980 at

February 1980 at Johns Hopkins Hospital Johns Hopkins Hospital by Dr. Levi Watkins, by Dr. Levi Watkins, Jr Jr

Types Types

• External Manual

External Manual Defibrillator Defibrillator

• Internal Manual

Internal Manual Defibrillator Defibrillator

Types Types

• Automated External

Automated External Defibrillator (AED) Defibrillator (AED)

• Implantable

Implantable Cardioverter Cardioverter-

• Defibrillator

Defibrillator

Capacitors Capacitors

• Stores electric charge

Stores electric charge when voltage applied when voltage applied (finite charge time) (finite charge time)

• Discharges current

Discharges current rapidly to load (more rapidly to load (more so than a battery) so than a battery)

C = C = ε εs / d s / d Charge Q=CV Charge Q=CV Energy E=(1/2)CV Energy E=(1/2)CV2

2

Discharge time t=RC Discharge time t=RC

Circuitry Circuitry

• Capacitor stores energy for

Capacitor stores energy for defibrillation defibrillation

• Cap charged to ~1000V

Cap charged to ~1000V

• Delivers 100

Delivers 100-

• 200 J to patient

200 J to patient

• Discharge time ~5

Discharge time ~5-

• 10ms

10ms

• Inductor used to create a finite

Inductor used to create a finite damped sine wave from DC damped sine wave from DC ( (Lown Lown waveform) waveform)

• Monophasic

Monophasic vs. biphasic

• vs. biphasic

waveforms waveforms

• Body modeled as impedance

Body modeled as impedance

• Body contacts

Body contacts – – 25 lbs. 25 lbs. pressure required to avoid pressure required to avoid static discharge static discharge

Application Application

• External Units:

External Units:

• Gel

Gel

• Lower Resistance

Lower Resistance

• Wet vs. Dry Gel

Wet vs. Dry Gel

• Apply Paddles; 25lbs

Apply Paddles; 25lbs

• Automatic vs. Manual

Automatic vs. Manual

• Electrodes

Electrodes

• Safer, Better EKG

Safer, Better EKG Readings Readings

Application Application

• Internal Units:

Internal Units:

• Only for those who are at

Only for those who are at severe risk; severe risk;

• Ventricular fibrillation (unproductive

Ventricular fibrillation (unproductive heartbeat), ventricular tachycardia heartbeat), ventricular tachycardia (abnormally fast heartbeat), long QT (abnormally fast heartbeat), long QT syndrome (an inherited heart disease) syndrome (an inherited heart disease)

• Placement:

Placement:

• Lead Wire from Cephalic vein to heart

Lead Wire from Cephalic vein to heart chamber chamber

• Electrode implanted lower chamber

Electrode implanted lower chamber heart muscle (LV or LA) heart muscle (LV or LA)

• Tech. Specs
• Tech. Specs
• Li

Li-

• Ion Battery

Ion Battery

• “

“Wand Wand” ” Programming over RF Programming over RF

• Electrodes; Platinum, Silicone

Electrodes; Platinum, Silicone

• Treatment

Treatment

• Pacing Regimen

Pacing Regimen → → Cardioversion Cardioversion → → Defibrillation Defibrillation

References References

• American Red Cross: Saving a Life is as Easy as A

American Red Cross: Saving a Life is as Easy as A-

• E

E-

• D

D

• FDA Heart Health Online: Automated External Defibrillator (AED)

FDA Heart Health Online: Automated External Defibrillator (AED)

• Resuscitation Council (UK)

Resuscitation Council (UK)

• History of defibrillation

History of defibrillation

• How an internal defibrillator is implanted

How an internal defibrillator is implanted from Children's Hospital Heart from Children's Hospital Heart Center, Seattle. Center, Seattle.

• http://www.arpansa.gov.au/uvrg/rginfo_p15.html

http://www.arpansa.gov.au/uvrg/rginfo_p15.html

• http://www.arpansa.gov.au/uvrg/rginfo_p15.html

http://www.arpansa.gov.au/uvrg/rginfo_p15.html

• http://www.medical.philips.com/main/products/resuscitation/bipha

http://www.medical.philips.com/main/products/resuscitation/biphasic_techno sic_techno logy/understanding_electricity.html logy/understanding_electricity.html