Future of CPR

ELCARE’S CRYSTAL BALL – A VISION FOR THE FUTURE

(Condensed from a lecture given November 2000 at Texas College of Osteopathic Medicine)

I’m Elroy Cantrell, DO, PhD,  an emergency physician for the past 15 years.   Prior to that

I was the chairman of the Pharmacology department at the Texas College of Osteopathic

Medicine in Fort Worth.

 

THE PROBLEM: I have had occasion to treat numerous cases of cardiac arrest and

have observed a considerable variation in the quality of care provided by emergency

technicians and paramedics in rural Texas.  I have also recognized several shortcomings

in the pharmacologic and technical management of cardiac arrest.   The American Heart

Association has encouraged an intense program of basic life support training in the US,

and expanded use of automatic electrical defibrillators  – yet the rate of rescues and

resuscitation from sudden cardiac death is still dismal.  The survival rate varies from

under 1% in large cities with limited CPR training,  high-rise apartments & traffic

congestion, up to 15% in Seattle, Washington where an aggressive CPR training program

and enhanced Emergency services has been implemented.  Texas has about 4-5%

survival.

 

THE HOPE: Recent research in resuscitation indicates that survival from sudden cardiac

death can be markedly improved with implementation of existing technologic

innovations.  Furthermore,  new devices under development can contribute to this

expectation of improved survival and improved quality of life.   —-  So how does the

new paradigm  work ?

 

THE NOW:  Sudden cardiac death is a major health problem in the US and the world.

The American Heart Association reports that about 350,000 persons in the USA

experience cardiac arrest (sudden cardiac death) each year.  Unfortunately, even under

the best circumstances of outpatient emergency care,  MOST DIE ANYWAY.  Only 1-

15% survive, depending upon regional resources and training.  Much more can be done

to improve these numbers.

 

The American Heart Association states that there is a decline in survivability of 10% for

each minute that electrical defibrillation is delayed.  According to Dr. Paul Pepe of

Southwestern Medical School in Dallas, the supporting data is actually pooled from cases

with and without CPR.  The original data from the three studies show that without any

CPR, death is virtually assured if defibrillation is delayed for as little as five or six

minutes.  In contrast,  one can expect some success with  defibrillation within 20 minutes

— if PROMPT CPR is provided !

 

The current guidelines for cardiac life support are published in many training manuals for

CPR.  The American Heart Association describes and recommends the sequence of the

“Chain of Survival” which includes:

 

1) Recognize the problem and call for help,

2) start CPR,

3) Electrical defibrillation at the earliest possible time, and

4) Advanced life support efforts.

 

Or, in short :  Provide CPR   —–   Prompt defibrillation  —– and if not successful do not

pursue a futile effort.

We know that the best blood circulation is obtained with a healthy, beating heart.   The

second best with a sick, but beating heart.  Third best is perfect CPR, even though that

can sustain life for only a few minutes as we now understand and provide CPR.   Fourth

best is a tie between poor CPR and doing nothing.  With our present understanding, the

bottom line is clear –  Without a functional heart,   survival is not possible.

 

But is that really true ???

 

THERE’S MORE ?  Recent research in resuscitation suggests that with the present

paradigm of care we may be doing – – –

 

too little

too late

too short

 

During the past several years reports of aggressive management with early application of

heart-lung bypass (San Diego, Detroit, Philadelphia, Japan, and other sites)  indicate

markedly improved physiologic and neurologic survival even after 30+ minutes of arrest

and failure of electrical defibrillation and conventional efforts.

 

These results are consistent with the notion that a contractured, oxygen-starved heart can

actually become an obstruction to passive flow of blood during sustained CPR.

 

We and others envision a new paradigm of resuscitation evolving over the next few

years.  The primary emphasis will be toward support of brain function and other vital

organs.   Less emphasis will be toward restoring a heartbeat but overall rescue efforts will

be extended.

 

As before, immediate and PERFECT CPR must be provided.  And, as before, electrical

defibrillation is provided as soon as possible.  Most times a normal rhythm deteriorates to

ventricular fibrillation (VF) or Ventricular tachycardia (VT)   or a state of  pulseless

electrical activity (PEA), also called electromechanical dissociation (EMD).  Finally, a

state of asystole evolves where no electrical activity can be detected.  The current

guidelines of the American Heart Association indicate that one should consider early

termination of rescue effort when asystole is seen.  — But we shouldn’t give up !

 

There are obvious benefits to advanced efforts to manage this “stunning” effect on the

heart with advanced care, including heart-lung support to allow time for the heart to be

“serviced” or replaced.

 

NO KIDDING !  If we can truly manage shock and support viability in vital organs, we

can expect  substantial improvement in outcomes.

 

If we  expand the delivery of prompt CPR and advanced care, then the technology

is certainly available (or on the horizon)  for sophisticated interventions which

could improve length and quality of life.  These include improved heart-lung

devices, artificial hearts, xenobiotic (animal) hearts, and lab-grown human hearts.

 

TA DA !  Such measures are now available or in final stages of development.

 

Following Cardiac Arrest there is a  brief window of opportunity to provide definitive

treatment and re-establish pump function.  With no external support (CPR) a few persons

have been resuscitated spontaneously, by coughing , or with precordial thump.

Application of electric defibrillation within a 4-5 minute window  can be lifesaving.

Survivability otherwise  is grim.  Early application of basic and advanced CPR can

double the time of the window of opportunity and increase  probability of  survival with

intact neurologic function.  Extensive community training in prompt application of CPR

and defibrillation has increased survival (as in  Seattle, Washington) to about 15%.

 

A study of recent reports of early use of heart-lung bypass in cardiac arrest indicates that

survivability can be improved greatly if applied within 30 minutes following arrest – even

after CPR and defibrillation failed.  Several hours on bypass allowed time for surgical

intervention and recovery of the “Stunned” heart in some cases.  Furthermore, many  of

the non-survivors would have benefited from replacement of the heart with a new

biologic or mechanical pump.

 

There is a  latin term   “SINE QUA NON”  which means “without which there is

nothing”.  There is a part of the scheme which clearly fits that term — Perfect and

Sustained CPR.

 

YES, in cardiac arrest the first critical element in survival is perfect and sustained CPR

until the heart can be re-started (defibrillated) or an adequate substitute can be provided

.

OUCH !  Unfortunately, barehanded CPR rarely provides the quality of CPR we seek,

and may even cause further injury to a victim if improperly performed.

 

Broken ribs and internal organ damage may result from improper or excessively applied

force.   Inadequate circulation may result from too little applied force.

 

Recent reports from the medical literature indicate that device-assisted CPR could

markedly improve performance by  CPR providers.  Presently only one device is

approved by the FDA for basic CPR —CPRplus — and only one device for advanced CPR

The Thumper.  Other devices have been invented, but all are still pending FDA

approval.  The studies reported with these are impressive.

 

Several other devices have been invented to assist providers of CPR.   A few of the most

recent devices are described here.  BASIC CPR assist devices rely on human strength

and endurance to power the effort.

The CPRplus is the only “new” CPR device ever approved by the FDA. It has been on

the market about 5 years.  A pressure display gauge  is attached to a bellows chamber

which is placed on the lower sternum.  This device monitors applied force and helps the

rescuer provide adequate force while minimizing hazardous excessive force on the chest.

A metronome in the carrying case paces the rhythm.

 

The Cardiopump was devised after a report in the San Francisco Examiner in 1989.  A

bystander applied push-pull force to the arrest victim’s chest with a plumber’s plunger.

The victim was subsequently resuscitated.  The theory of its advantage is that lifting the

anterior chest wall enhances blood return to the heart.  Although not approved in the

USA, it has been employed in Europe and Australia.  The device requires 15% additional

energy to operate and tires the rescuer more rapidly.

 

Lifestick exploits the reported advantage of abdominal counterpulsation to enhance

blood return to the chest.  The two legpads are applied to the chest and abdomen and a

“See-Saw” rhythm is applied.  Since the abdominal stroke  also forces blood toward the

head, the effective stroke rate is doubled and blood flow to the brain is increased.  This

device is thought to require less energy by the rescuer, as well.  This device has not yet

been approved by the FDA.

 

We have reported results of our own basic CPR device “The Grip” and the

improvement in CPR performance by paramedics is remarkable.  Our studies in

experimental pigs indicate 50-80 % of normal blood flow to the brain can be expected

with “The Grip”.

 

The disposable chestpad is imprinted with brief reminders of the current parameters of

basic CPR.  (You OK? – Call help – Check pulse – 2 breaths),  and the 2:15 breath-to-

strokes ratio for single rescuer vs 1:5 ratio for two rescuer CPR.

 

Notches at the ends of the chestpad help to align with the xyphoid process and the

sternum.  A peel-off backing exposes sticky adhesive to affix the pad to the bare chest.

There is no danger of misplacing or moving the device after being properly applied.

 

A handgrip allows for firm control of the device and allows the entire palm and hand to

remain in a comfortable position during the rescue. Below the handgrip is the basepiece

with a force transducer and microswitches.

 

The display module contains a light and speaker to provide visual and audible output

from the metronome timer.  A rate selector allows one to proceed at 80 or 100 strokes per

minute.   The stroke counter window displays the cumulative strokes up to a preselected

count of  5 or 15 counts, then a chirp is provided to remind the rescuer to give rescue

breaths.  A unique feature is the tilt monitor.  One of  four microswitches in the base may

be triggered if force is not applied straight down onto the sternum, one of the four  L.E.D.

lamps points in the direction of misapplied force.

 

With instant feedback of performance  corrections in rate, force and direction can be

made “on the fly”.  To further improve performance, we suggest abdominal binding

during CPR.

 

Consistent with recent studies by others, we  found that CPR performance was

substantially augmented with our device.

 

Six persons from the Fairfield, Texas EMS were tested on a recording Resusci-Anne

employing conventional bare-hand compressions as taught by The American Heart

Association, and with our performance assist device.

 

Persons were tested both on the floor of the ambulance barn and in a moving ambulance

to simulate a rapid trip to the hospital.

 

The percentage of “adequate” strokes per minute was surprisingly variable among these

persons, when bare-hand technique was used, but the device which provided stroke-to-

stroke feedback on performance allowed all but one rescuers to maintain or reach near-

perfect performance even when pitching around in the back of a moving ambulance.

 

POWERED CPR DEVICES are intended for sustained rescue efforts, and relieve the

rescuer of his own physical effort.  Furthermore, stroke-to stroke variability may be less.

 

The Thumper has been sold in the USA for about 30 years.  It was marketed prior to the

date FDA assumed authority over new medical devices.  The pneumatically powered

device uses the oxygen supply bottle to power a piston in the arm of the unit, providing a

preset stroke distance. The victim is positioned on the backboard.  The piston pad often

becomes displaced during use and poor performance or injuries can result.  Price is about

$5300.

 

Vest CPR was developed and studied at Johns Hopkins Hospital and University over the

past 15+ years.  Blood flow is achieved by pumping the entire chest with a

circumferential pneumatic vest. Clinical studies indicate improved success as compared

with basic CPR. Combined with ventilation and/or abdominal maneuvers the blood flow

to brain is improved. Cost projection is about $50,000 per device.  The device is not yet

marketed in the USA.

 

Under development is our own Portable Automatic Resuscitation Device (PARD) , an

electrically powered chest compressor.

 

Virtually perfect CPR can be attained with this device.  It is quickly applied and the

operator then may set the strap tension & tap the “go” button.  One can select

preferentially stroke distance or stroke force as the primary determinant of compressions.

The rate can be set at 60, 80, or 100 per minute. The base, with a force transducer, rests

in the socket of the chestpad described above (“The Grip”).   A battery pack in the upper

section can provide 10-15 minutes of 100 pound strokes at a rate of 100 per minute.  This

can allow plenty time to hook up to a secondary battery, wall power, or vehicle power for

continued CPR.  As new procedures for abdominal maneuvers and ventilation support

become more commonly used, these devices will interface quite well and should make a

significant impact on survivability.  Price will be competitive.

 

TONGUE-IN-CHEEK  or  HAND-ON-BELLY-BUTTON ?  A  position and

technique is described in the ACLS manual for relieving tracheal obstruction (Café

Coronary). This variation of the  Heimlich Maneuver has the victim lying on his back and

the rescuer straddles the victim’s thighs.  Repeated abdominal thrusts are administered to

force air -and the obstruction -from the victim’s airway.   Could abdominal strokes be an

alternate form of CPR ?

 

Our studies in animals suggest that repetitive abdominal strokes could provide adequate

blood flow to brain with less applied force.  Perhaps  children or small rescuers could be

more effective with “Abdominal CPR” ???

____________________________________________________________________

Percent of  “Beating Heart” Values

Chest Only            Abdomen Only                    Simultaneous

 

CAROTID FLOW (%)        27 +/-  4                     29 +/-  4                                 49 +/-  6

 

MEAN  BP (%)                     40 +/-  5                     42 +/-  2                                 60 +/-  3

_____________________________________________________________________

In this study with 6 pigs, we monitored blood pressure and carotid blood flow during

CPR.  Two GRIP devices were employed to monitor compressions on the chest and

abdomen, respectively.  Data here are reported as percent of control values prior to

fibrillating the heart.  With 100 pounds of force on the chest we maintained about 40% of

normal blood pressure and 27% carotid blood flow.  With about 60 pounds of force with

the abdominal strokes, the blood pressure and carotid flow were about the same as with

chest compressions.  There was an additive improvement in the “minute blood flow”

when both maneuvers were applied either simultaneously, or (not shown here) with

alternating strokes.

 

Our data and others indicate that device-assisted CPR could support brain and other vital

organs to prolong the window of opportunity until application of definitive treatment

with “Ultra-CPR” and surgery described previously.

 

Advances in resuscitation from cardiac arrest have been slow and frustrating.  The

development and deployment of automatic electric defibrillators has already made

stepwise improvement in survival, but even so the percentages are dismal.

 

Technology is now available to provide more aggressive efforts and save more lives. The

history of thrombolytic therapy, electrical defibrillation, and other novel procedures

indicates that persons who experience cardiac arrest (and meet predetermined criteria)

can be rescued with an enhanced quality of life.

We just need to “make it happen”   – –      El