X-Message-Number: 2948
Date: 28 Jul 94 20:37:04 EDT
From: Mike Darwin <>
Subject: SCI.CRYONICS BPI Tech Brief #15

BPI TECH BRIEF # 15

This is the last installment (for now) of the Standby 
Manual.  I have completed three more chapters including a 
rough draft of the chapter on premedication; the 
premedication chapter was an especially difficult one.  I 
have also completed the final version of the Chapter on 
Standby Staff Safety and Infection Control.  Ahead lie 
Chapters on Euthanasia, Legal aspects of Standby and 
cryopreservation, Basic Principles of Home Nursing Care and 
possibly yet another chapter or two on other subjects 
related to Standby.  

I am especially interested in feedback from people on issues 
that you feel are left unaddressed so far (in the material 
covered) or questions which are raised, implied or otherwise 
not dealt with well.  This kind of feedback will help me 
substantially in upgrading the final, printed version of 
this book.

Of  the Chapters I have completed, I am *least* satisfied 
with this one (Chapter 6).  Why?  Because it just isn't good 
enough at doing what it is really supposed to do: guide 
standby personnel in determining when and how the patient 
will experience cardiac arrest.  I have two frustrations in 
writing this Chapter.  The first is that it is an impossible 
task.  There are so many ways that a system as complex as a 
human being can fail that there are no substitutes for vast 
experience.  The ideal person would be someone of Feynman's 
intellect and perspacity, with the combined career data base 
of a seasoned neurologist, cardiologist, internist, hospice 
nurse, oncologist, hematologist, etc...  Alas, we have no 
such person and even very experienced medical people are 
tripped up or (wise enough to be) unwilling to make 
prediction(s) about when a patient will arrest.  The second 
is the lack of more experience an actual measurements which 
might serve to clarify the situation a great deal.  In cases 
of slow death (and even in many cases of so-called sudden 
death) I feel that there are probably many fairly reliable 
markers which can be used to determine the time-course to 
cardiac arrest.  But we have to *look*  for for them.

Some systems for predicting patient survival outcome such as 
the APACHE system already exist.  BPI has (and uses) a 
simple version of that program.  The full fledged APACHE 
program costs upwards of $250,000 and requires a large 
mainframe to run.  It won't tell you time course with a lot 
of precision, but it *will* tell you whether or not the 
patient will survive the hospitalization (providing the 
tests and measurements the program requires to work are 
being made) with better than 90% accuracy.  Some larger 
hospitals are already using APACHE to triage patients in the 
ICU and CCU and contain costs.  This is how APACHE Medical 
Syatems, Inc. makes money on the program and why they can 
charge what they do. (In all fairness it *is* a tremendously 
sophisticated program and it is fraught with liability  -- 
just wait till the public realizes this thing is already in 
use to triage right now (of course they don't use that 
word).  In the final edition of this chapter I intend to 
spend some time dealing with APACHE and suggesting ways we 
can use it if the  hospital that has the software is 
cooperative and/or the patient is in a facility with APACHE 
capability (NOTE: many facilities won't tell you they are 
using APACHE).

I mention APACHE here because it bears paralells with my 
perdicament in writing Chapter 6 and with the perdicament of  
standby persnnel in predicting time course to legal death.  
Everybody said APACHE was impossible.  But it works, 
surprisingly well.  We need to start looking at our dying 
patient's *closely* and doing lab analysis for lactates, 
ammonias and other markers which may be highly predictive 
and we need to start graphing this data.  I believe we will 
find markers which, while not they will not be 100% 
predictive, will at least be very useful as a guide, much as 
the APACHE system is.  I would like to see ALL cryonics 
organizations work together to build this data base by 
openly sharing their records and agreeing to standardize 
data gathering and laboratory monitoring during standby and 
transport.  Our statistical base (individually) is just too 
small otherwise.

Having said the above about what we need to *discover* I 
would also say that one of my great sources of frustration 
and guilt is what I (we) don't know already that we *should* 
know.  You will see warnings about pulse oximetery in this 
chapter and its use on low hemoglobin patients.  This was 
hard won information for me.  Yes, I rememered the "facts" 
but they didn't mean nearly as much to me as they did 
*after* I had a patient experience cardiac arrest when the 
standby team was neither present or prepared because I 
overlooked clinical signs of hypoxemia (the patient was 
agitated and *nasty*, and while he had previously been 
agitated and confused while on morphine, he was never 
aggressive -- a likely tip off that it was hypoxia due to 
anemia rather than his usual problems with opiates).   That 
patient experienced uneeded minutes of warm ischemia because 
of my lack of experience in applying a "book fact" to real  
life, *and* because of the problem (common to health care 
providers and nuclear reactor operators everywhere) of not 
wanting to think or see the worst even as it begins to 
unfold in front of you.  If there is any take-home message 
in this chapter it is in the opening quote.  Too bad I read 
it on the plane coming *back* from that patient's standby 
when he was already in the cargo hold and the "incident" was 
over.  Hopefully you will learn from my mistakes.  -- MD

Chapter 6 of STANDBY: END-STAGE CARE OF THE HUMAN 
CRYOPRESERVATION PATIENT

by Michael Darwin with Charles platt

Copyright 1994 by Michael G. Darwin.  All rights reserved.

Chapter 6 

Standby and Transport Logistics 


The first step in caring for a critically ill patient is to 
realize that he is in serious difficulty. This may not be 
easy, and seemingly inconsequential findings may presage 
disaster. The gravity of the situation may not be apparent 
even though there is serious malfunction of one or more 
systems. A subtle change in a physical sign could be the 
first indication of general collapse. It has been our 
personal experience that early warning signs are overlooked 
or dismissed unless the physician is ever aware of the 
possibility of serious trouble. There is a recurring 
tendancy even after one has "learned his lesson," to dismiss 
an abnormal finding by ascriboing it to an unimportant 
cause. It is not enough to recognize that a physical sign 
could indicate serious difficulty. The weakest link in 
patient care is the tendency of the physician to convince 
himself that somehow everything will be all right. Every 
clue must be sifted and analyzed. Every unexpected sign must 
be understood. 

                                 --Stephen M. Ayers, M.D. 
                                Care of the Critically Ill 
                                Second Edition 

The standard Local Standby Kit (LSK) contains two "E" 
cylinders of oxygen, capable of powering the Michigan 
Instruments Heart-Lung Resuscitator (HLR) for approximately 
thirty minutes. This will usually be sufficient to transport 
the patient via hearse or ambulance from the hospital or 
nursing home to a mortuary or other facility where extended 
external cooling and/or blood washout can be carried out. 

Arrangements should be made with the cooperating mortuary 
(or, if legal death is occurring at home, with the home-
hospice program) to provide at least two "H" oxygen 
cylinders, each of 220 cubic foot capacity, or larger. 
Always try to conserve E-cylinder oxygen for use when the 
patient is being moved by a vehicle. If the patient is 
initially hospitalized, try to use the hospital's oxygen 
supply while waiting for the mortician or ambulance. In most 
hospitals, you will find a wall outlet for oxygen in each 
room. To tap into this supply, you will need to obtain a 
special adapter or coupling from the respiratory therapy 
department of the hospital or carry an assortment of 
adapters for systems commonly in use in your country. 

If a wall adapter has a flow restriction device such as a 
flow meter, it will not provide enough pressure to run the 
HLR. Only a wall oxygen connector with a DISS fitting (see 
figure 3-1) can be used. 

If the hospital does not have or will not make available 
this type of fitting, you should ask for an H cylinder or 
other source of bottled oxygen. Alternatively, you can seek 
permission to bring a source of bottled oxygen in from 
outside. Please note that when you are moving an oxygen 
cylinder through the halls of a hospital, you must always 
mount it on a proper cylinder truck or hand cart. This is a 
safety requirement which is vigorously enforced in all 
hospitals.  Once the cylinder is in the patients room, it 
must be secured to the wall or placed in an anti-tip base.  
Alternatively, if the cart is a four wheel type which allows 
the cylinder to rest stably at an angle, the cylinder may be 
left *chained* to the cart.

A word of caution is in order about getting prompt access to 
oxygen under emergency conditions in a strange city. Most 
locales now require a prescription for medical oxygen. You 
can safely substitute welding gas, but it is rarely 
available on a 24-hour basis. Therefore, you should always 
try to plan ahead and have oxygen ordered and delivered to 
the home or mortuary as soon as you hear that the patient is 
terminally ill--even if the patient is expected to survive 
for weeks or months.
 
Sometimes, of course, it is not possible to plan ahead, and 
transport technicians should know the procedure for calling 
in a prescription for oxygen, either as a physician or the 
agent for a physician. Unfortunately, cylinder oxygen is 
becoming increasingly hard to obtain on a 24-hour basis. The 
need for it has been diminished by widespread use of oxygen 
concentrators (which plug into the wall and make oxygen from 
room air) and liquid oxygen systems. In many cities and most 
small towns, rapid, 24-hour delivery of oxygen in cylinders 
is becoming a thing of the past. Consequently, it's even 
more critical to plan ahead to insure a supply. 

-------------------------------------------------------
WARNING: Mortuary personnel are generally unfamiliar with 
the safe handling of oxygen. The transport technician will 
need to supervise loading, unloading, and handling of oxygen 
cylinders with great care. Remember always the risk of a 
CATASTROPHIC FIRE at the mortuary or en route to it. Within 
the confines of a vehicle, oxygen concentration can easily 
rise to a dangerous level. Consequently, you must warn 
mortuary or other personnel NOT TO SMOKE AS THEY MAY 
NORMALLY BE ACCUSTOMED TO DOING SO. 
----------------------------------------------------------

It's easy to forget this precaution when your prime concern 
is caring for the patient, but mortuary personnel frequently 
smoke and are especially inclined to do so at times of 
stress--such as moving a patient who is on HLR support. 
Remember, in a closed vehicle where there is a high 
concentration of oxygen, a lighted cigarette can almost 
guarantee a serious fire. Remember the Apollo fire!

Access To Ice 

You will need 300 to 400 pounds of ice to cool the average 
160 pound (72 kg) man, plus another 200 pounds for shipping 
the patient. If the institution which has control of the 
patient does not have access to this amount of ice or will 
not make access available, you will have to get it from an 
outside source. 

There are 24-hour ice services in most cities. After you 
obtain ice from an outside source, a mortuary may keep it 
for you in one of their freezers (if they have one), or a 
hospital may allow you to store it in one of their food 
freezers. Note that if the ice has melted at all along the 
way, refreezing it may turn it into a semisold mass, and 
you'll need an ice pick or screwdriver to break it up. 

If you are conducting a standby in the patient's home, you 
must arrange to have a large supply of ice on hand, or you 
must find a 24-hour source nearby. Convenience stores such 
as 7-11 can usually meet this need. If one of these stores 
is nearby, you may be able to delay buying ice until the 
patient becomes frankly agonal, so long as enough personnel 
are available to go out for ice when the time comes. 

If there is no reliable source of ice nearby, and no freezer 
in which to stockpile it for quick access, good quality 
picnic chests can be used to store ice with relatively 
little melting. The Igloo brand, with foam-insulated lids, 
is recommended. You will need six 22-quart chests for an 
average standby. 

Do not use inexpensive, "soft" expanded polystyrene picnic 
chests that are sold in drugstores and supermarkets. They 
will leak copiously and will not hold ice for long enough to 
be economical. 

Arranging Prompt Release of the Patient 

If the hospital has a staff mortician or diener (lab 
assistant) who is responsible for handling and processing 
remains in the morgue, you should contact this person and 
ask for his help. If you take care of this early on, you'll 
have a much better chance of obtaining prompt release of the 
patient. A staff mortician can significantly delay the 
release of the patient from the hospital if he feels that 
you have ignored him or treated his authority with 
insufficient respect. 

Whenever possible, try to see that a death certificate is 
filled out in advance, leaving the lines blank for the cause 
of death and the signature of the pronouncing physician. 
If the patient is at home and the hospice is unable to 
provide round-the-clock nursing service, you will need to 
make special arrangements for quick pronouncement of death. 
This is generally done by having a registry nurse in 
attendance. You will definitely need to clear this with the 
hospice agency, and possibly with the coroner or medical 
examiner as well. 

Securing a Private Room 

If the patient is in an open ward or undivided Intensive 
Care Unit (ICU) and the institution seems cooperative, you 
shold ask for transfer to a private room or cubicle 
(preferably near an exit) to minimize disruption and attract 
as little attention as possible during stabilization and 
removal. If the patient is unequivocally terminal, reassure 
the hospital that the cryonics organization (if it is their 
policy) will pay for the added expense of a private room. 

Evaluating the Patient's Condition 

Once the basic administrative and physical details outlined 
above have been dealt with, the team leader should see the 
patient and to ask to examine the chart. A general 
assessment of the patient should be made at this time, and 
the evaluation should be carefully recorded with proper 
notes. 

Is the patient alert and oriented as to person, place, and 
time? Is the patient comatose? What is the patient's fluid 
status: edematous, dehydrated, in balance? Whenever 
possible, obtain a photocopy of the recent medical history 
and daily "graphic record" from the nursing staff or the 
attending physician. This may be difficult, and you may have 
to use the Patient's Directive and Power of Attorney. You 
should be concerned with the current status and status for 
the previous 24 hours of the following key items: 

Temperature 
Blood Pressure 
Pulse 
Neurological Status (see Table 1, Glasgow/Pittsburgh Coma 
Scale) 
Fluid Balance (pulmonary edema?) 
Hematological Status (bleeding or coagulopathies?) 
Laboratory Test Results 
Medications Currently Being Administered (or given during 
the previous 48 hours) 
Surgical/Diagnostic Procedures 
Unusual Findings 
Prognosis 

The patient's temperature and fluid balance are of primary 
importance, since they can profoundly affect the course and 
quality of resuscitation and stabilization. If a patient is 
markedly febrile (running a temperature), CPR will be even 
less effective at meeting metabolic demand than normal. 
Remember to note this on the transport records. Likewise, 
the presence of edema will affect the efficacy of CPR due to 
diminished lung gas-exchange surface area. Severe 
dehydration could mean inadequate circulating blood volume 
and thus inadequate blood pressure and tissue perfusion 
during CPR. 

Predicting Cardiac Arrest 

Once you have evaluated the patient's condition, you should 
try and establish a probable time of legal death. Is the 
patient likely to experience cardiac arrest in a few 
minutes, a few hours, or a few days? Your assessment will 
profoundly affect every aspect of the standby operation. 
Obviously, if the start of ischemia is only minutes away, 
you will need to summon essential support personnel (such as 
the cooperating mortician or ambulance service). You will 
also need to begin drawing up medications. 

On the other hand, if the life expectancy seems likely to be 
numbered in days rather than minutes, your most immediate 
priority will be to determine where to situate yourself. 
I cannot overstate the importance of making a reasonably 
accurate assessment of when cardiac arrest is likely to 
occur. Typically, there will be only one set of transport 
medications available on-site for a local or remote standby. 
Once the medications have been drawn up, they must be used 
(even if promptly refrigerated) within no more than 24-48 
hours. If your estimate of the patient's condition is 
incorrect, you may find yourself lacking transport 
medications when they are needed. 

The overall level of readiness may be even more important 
than the issue of when to draw up medications. There is 
almost no disaster more demoralizing (short of not being 
able to cryopreserve the patient at all) than being 
unprepared when the patient experiences cardiac arrest. Here 
again, assessing the patient with a reasonable degree of 
reliability is vital, particularly when essential transport 
personnel must be located off-site for any reason. 

Unfortunately, a general assessment is rarely 
straightforward. Human beings are complex, and many factors 
will determine when this complex system fails. Nevertheless, 
there are a few useful guidelines. it should be noted that 
using these "markers" as predictors with any precision 
requires both skill and experience. Whenever possible, the 
transport technician should trust the judgment of those who 
have the greatest clinical experience. In particular, the 
nurses caring for the patient may be able to tell with a 
fair degree of accuracy when the patient will experience 
legal death. You should ask them for an assessment and give 
their estimations considerable weight. 

Key Factors to Consider 

There are two fundamental ways that a patient can experience 
cardiac arrest: acutely, as a result of very rapid 
destabilization (perhaps cardiac arrhythmia or hemorrhage), 
or slowly (perhaps as a result of decompensation and shock). 
The presence of arrhythmias--which can precipitate sudden 
cardiac arrest--can be disclosed by discussing the patient's 
condition with the nursing staff providing care. The range 
of cardiac conditions that can lead to sudden cardiac arrest 
is large, and a detailed discussion of the risk factors for 
sudden cardiac arrest is beyond the scope of this guide. 
Also, the presence of arrhythmias that are linked to sudden 
cardiac arrest is usually not going to be very useful in 
determining with any degree of precision when the patient i!
s going to arrest. 

Arrhythmias 

Having said this, there a few specific guidelines that can 
be given. Some cardiac arrhythmias are a cause for concern 
only in the context of the patient's overall condition. For 
example, premature ventricular contractions (PVCs) may occur 
in a variety of disease states, especially following acute 
myocardial infarction. Depending upon their nature and 
frequency, they may or may not be serious. However, in a 
patient who is entering the agonal shock period, the 
appearance of PVCs should be great cause for concern. If the 
PVCs become frequent, occur in runs, or are accompanied by 
the R-on-T phenomenon, you should be alert for the 
possibility of impending cardiac arrest. Even if the patient 
does not arrest as a result of the arrhythmia, it may 
indicate that shock is deepening and that cardiac arrest may 
be close. 

One arrhythmia which demands serious attention is 
ventricular tachycardia (V-Tach). When it is observed in a 
terminal patient, this arrhythmia must always be viewed as a 
precursor to ventricular fibrillation and cardiac arrest. 
Treatment is normally (in a non-terminal patient) immediate 
and very aggressive, usually through a combination of drugs 
and cardioversion (electric shock delivered to the heart). 
When V-Tach is observed in a terminal cryopreservation 
patient, the transport technician should alert other team 
members (waking them if necessary), lay out medications, and 
take all other necessary steps to insure readiness. Since V-
Tach can sometimes be sustained for hours, it is probably 
not wise to draw-up transport medications. However, if the 
V-Tach is associated with evidence of inadequate perfusion, 
such as a fall in blood pressure or alteration in 
consciousness, final preparation of transport medications 
should be undertaken. 

Evaluating Tissue Perfusion 

Shock is the pathway to all non-sudden cardiac arrest and 
the Transport Technician should understand its elements and 
the many ways in which it can present itself. Simply put, 
shock is inadequate blood flow or inadequate tissue 
perfusion as a result of decompensation or frank failure in 
one or more of the homeostatic mechanisms responsible for 
delivering blood flow to tissues. Shock can result from the 
following factors, individually or in combination: 
inadequate cardiac output secondary to a diseased or failing 
heart, inadequate distribution of a very large cardiac 
output, or insufficient blood volume for the heart to pump. 
In turn, the possible causes of pump failure or inadequate 
volume could be many. Hemorrhage may deplete circulating 
volume, and so may altered capillary permeability, which 
allows vascular fluids to leak out of the circulatory system 
and into the tissues. Whatever the cause, shock is the 
proximate cause of all slow death. 

Low blood pressure is often, but not always, associated with 
shock. A patient who is in shock may have a centrally 
measured mean arterial pressure of 70 mm Hg, and yet have 
grossly inadequate perfusion of limbs and even core organs. 
The critical element is not pressure or even "flow," but 
adequate perfusion. In septic shock, for instance, flows may 
be very high and yet be inadequate. The point is that the 
patient has to be considered as a unit and in context, 
rather than on the basis of any isolated number. The 
assessment points given below are designed to help you to 
make that assessment. Beware, there is no "royal road" to 
achieving clinical skill in patient assessment. 

Level of Consciousness 

The patient's level of consciousness, considered with the 
patient's diagnosis and the other factors below, is one of 
the most valuable and easily evaluated indicators. The body 
will maintain cerebral perfusion as long as possible, often 
at the expense of other organ systems. Thus, when 
compromises in neurological function occur as a result of 
shock, they are often evidence of the final phase of 
decompensation. If the patient has been conscious and the 
level of consciousness deteriorates, it may be an ominous 
sign that cardiac arrest is approaching. 

Similarly, changes in the patient's demeanor may be 
critical. Combativeness and hallucinations are two of the 
earliest signs of cerebral hypoperfusion and should be given 
considerable weight when you evaluate the likely time to 
cardiac arrest. In order to evaluate these changes 
objectively, you will need to interrogate the patient. Some 
guidelines are presented below. When performing an 
evaluation, always compare the left side of the body with 
the right and current responses with prior responses. 

Cortical Function 

Assess Response to External Stimuli 
* Degree of stimulus required to elicit a response 
* Degree of response to the stimuli (use the 
Glasgow/Pittsburgh Coma Scale; see Table 3-1) 
* Presence of weakness or loss of function 
* Progression of deterioration 

Assess Mental Status and Cognitive Function 
* Short-term memory 
* Long-term memory 
* Calculation 
* Reasoning 
* Orientation to person, place and time 

Assess Motor Function 
* Compare the left side with the right side 
* Muscle strength, pushing or pulling against resistance 
* Grip strength 
* Motor speech--assess for motor aphasia 

In patients who are obtunded or comatose, it is important to 
evaluate cranial nerve function. Deteriorating cranial nerve 
function should be considered a warning sign that cardiac 
arrest is usually no more than four to six hours away. 

Cranial Nerve Function 
* Assess pupil reaction, size and shape. Pupils should be 
round and equal in size within 1-2 mm. 
* Pupil reaction to bright light should be brisk. Shine a 
light in one eye and check for constriction of the pupil. 
Check the other eye, too. Through internuncial pathways, it 
should mimic the response of the eye that is exposed to 
light. This is known as a consensual response. Pupillary 
responses should be carefully documented during the agonal 
phase since failed pupillary reactivity is probably an 
indication of gross cerebral hypoperfusion or total 
ischemia. 

[insert tables and charts] 

The lower the combined total score of the two scales, the 
worse the patient's condition and the shorter the likely 
time interval to cardiac arrest. Maximum possible score: 30. 
Minimum possible score: 9. 

At the end of this chapter you will find a worksheet to 
evaluate the patient using the Glasgow/Pittsburgh Coma 
Scale. 

Reflexes 
* Assess the corneal reflex by briefly and lightly touching 
the corneas with a piece of cotton or soft gauze. The eyes 
should close. 
* Assess the blink reflex by touching the eyelashes lightly. 
The eyes should close. 
* Assess the Babinski reflex by stroking the exposed skin of 
the sole of the foot. Moving upward from the heel, stroke 
the outer edge of the sole and then stroke across the ball 
of the foot. The toes should curl down in response. If the 
big toe moves upward toward the knee and the other toes 
flare out, the reflex is positive, which is abnormal in 
someone who has learned to walk and, during shock, may 
indicate cerebral hypoperfusion. 
* Assess joint reflexes by tapping the limb with a reflex 
hammer to stretch the tendon. In a normal functioning state, 
the limb should move to shorten the tendon. 

Cardiovascular Assessment 

Central Circulation 

One of the first, most important, and easiest things to 
assess is the patient's circulation. Look for a bluish tint 
in the mucous membranes of the conjunctivae and the lips, 
indicating the presence of an increased amount of reduced 
hemoglobin (central cyanosis). An important caveat about 
cyanosis is that (as will be discussed in greater detail 
shortly in the section on pulse oximetry) cyanosis may not 
be evident even in the presence of marked hypoxia or shock 
if the patient's hemoglobin is 5g/dl or less. Symptoms which 
may accompany cyanosis (and/or hypoxia when cyanosis is not 
present, i.e. during severe anemia) are tachycardia 
(increased heart rate), tachypnea (increased breathing 
rate), and dyspnea (shortness of breath) and confusion 
and/or hostility or combativeness. 

Peripheral Circulation 

When a patient is agonal and the body is attempting to 
compensate for failure of one or more homeostatic 
mechanisms, circulation to the brain and core organs tends 
to be maintained at the expense of other areas. Usually, the 
body shunts blood flow away from organ systems which can 
tolerate periods of reduced or absent flow, such as the 
limbs, skin, and the gastrointestinal system. In such 
patients, the peripheral circulation usually becomes 
compromised in a very consistent fashion. As the more distal 
parts of the body (such as the lower extremities) begin to 
experience failed perfusion, you should notice pallor, 
cooling, and an increase in capillary refill time beyond two 
seconds. The nail beds will loose their normal pink color 
and become cyanotic, and the arms and legs will become cool 
to the touch. 

When capillary refill times increase to four or more 
seconds, the limbs assume a mottled purplish appearance. In 
some cases there may even be signs of dependent lividity 
where blood in the limb, under the influence of gravity, 
settles into the most dependent part of the tissues. This is 
normally a postmortem change but it may also be seen in 
patients with very protracted agonal courses; particularly 
in AIDS patients, the extremely elderly, and in patients 
dying of dehydration. If you notice these changes in a 
patient's circulation--particularly in conjunction with 
abnormalities in vital signs (low blood pressure or pulse), 
you should expect that cardiac arrest will occur within a 
few hours at most. 

Vital Signs 

Primary vital signs are generally defined as blood pressure, 
pulse rate, and respiratory rate. In many situations, these 
signs may be a reliable guide to the agonal time course. Of 
course, the patient's underlying condition and status will 
also have considerable relevance. For instance, extreme 
tachycardia (elevated heart rate) will be tolerated far 
longer in a young marathon runner in shock after an accident 
than in an 86-year-old heart-attack victim. Still, there are 
certain vital signs which cannot be tolerated by any 
individual. A peak systolic blood pressure of 50 mm of 
mercury or less is seldom tolerated by the heart for more 
than an hour. Terminal patients (i.e., those in whom no 
resuscitation intervention is planned) with peak systolic 
pressures of 50 mm or less should be considered frankly 
agonal and in imminent danger of cardiac arrest. Sustained 
peak systolic pressures below 80 mm Hg should also be 
considered cause for concern, particularly in the presence 
of other abnormal vital signs (tachycardia, bradycardia, or 
Cheyne-Stokes respiration) or evidence of peripheral 
vascular shutdown. On the other hand, if a patient's 
systolic blood pressure is 70 mm Hg while the other vitals 
appear stable and central and peripheral perfusion are good, 
the low blood pressure is probably not predictive.

---------------------------------------------------------
 NOTE: Blood pressure readings are given as the systolic 
pressure over the diastolic pressure; for example, 120/70. A 
few adults may have very low normal blood pressure, even as 
low as 70 systolic. The difference between the patient's 
normal pressure and the current pressure may be more 
relevant than an absolute value. 
------------------------------------------------------------

It is very important to remember that for arterial pressure 
to be measured reliably, you need a central catheter rather 
than a cuff. Quite commonly, a cuff-measured pressure may be 
nonexistent or very low, while a reading of central arterial 
systolic pressure may be 80 or even 100 mm Hg. 

Tachycardia and bradycardia are also indicators of impending 
cardiac arrest, particularly when considered in light of 
other vitals signs. Typically, heart rates higher than 150 
to 175 bpm are not sustainable for more than a few hours. 
Heart rates over 120 bpm are cause for concern, particularly 
if the blood pressure is less than 100 mm Hg or other signs 
of decompensation such as peripheral vascular shutdown are 
present. 

In the case of bradycardia, it must always be assessed in 
the context of the patient's overall condition. Some 
patients can tolerate heart rates in the range of 30 to 40 
bpm for extended periods of time, particularly if the 
bradycardia is a result of a conduction defect(s) and has 
developed over a long period. Alternatively, a patient in 
serious distress who is classified as "dying" and has a 
heart rate of 40 bpm (down from a normal or elevated heart 
rate) should be considered at high risk for imminent cardiac 
arrest. 

The respiratory rate varies so widely, it cannot be used as 
an indicator by itself. However, Cheyne-Stokes syndrome (a 
respiratory pattern consisting of stepped, sonorous intakes 
of air; see Glossary for details) is a frankly agonal sign 
when coupled with other abnormalaties in vitals. If it is 
present, the transport technician should prepare for cardiac 
arrest within 24 to 48 hours or less. Very low respiratory 
rates or respiration characterized by increasingly long 
periods of abpnea (transient cessation of breathing) should 
also be considered prognostic of impending cardiac arrest. 
The "death rattle" is a fairly distinctive bubbling or 
gurgling respiration which results from a combination of 
impaired consciousness and mucous accumulation. This is a 
very reliable sign that cardiac arrest is near, although 
there are occassional exceptions.  Finally, the presence of 
so-called classical shock, as indicated by hypotension (low 
blood pressure) with tachycardia and diaphoresis (sweating), 
should be considered a serious warning sign. If the 
patient's skin is cold and clammy, respirations are fast and 
shallow, and blood pressure is low, the patient can be 
considered in shock and not far from cardiac arrest. 


Figure 6-4: Correlation of mean arterial pressure (MAP) and 
heart rate in a patient dying from dehydration and pulmonary 
insufficiency (secondary to end-stage adenocarcinoma of the 
lungs) with clinical signs and occurrence of cardiac arrest. 


Urine Output/Fluid Status 

Urine output is probably the second most important general 
indicator of the progression of shock. When a dying patient 
becomes oliguric (defined as less than 30 cc of urine output 
per hour) or anuric (no urine output), it is a sign that the 
kidneys are no longer receiving adequate blood flow and 
cardiac arrest can be expected within hours or, at the 
extreme, a day or two. Note that oliguria and anuria can 
only be assessed accurately and reliably if the patient has 
a bladder catheter.
 
Some moribund patients may have a naturally low urinary 
output, resulting in long periods (up to a day) between each 
instance of urination and the next. This should not be 
mistaken for anuria. 

Laboratory Measurements 

There are clinical laboratory tests and measurements which 
can help in assessing the time to cardiac arrest, but when a 
terminal patient is receiving orthodox treatment, these 
tests are seldom performed. If a patient still has some 
chance of recovery and is receiving acute care in an ICU or 
CCU, you are more likely to get useful data such as the 
following: 

Arterial Oxygen Tension 
A paO2 (the concentration of oxygen in the blood) of less 
than 70 mm Hg in a patient breathing 100% oxygen on a 
ventilator is an indicator that cardiac arrest may be 
imminent. 

Blood Lactate 
Metabolic acidosis with elevated blood lactate levels (over 
1 mEq/dl) indicates inadequate perfusion. 

pH 
Blood pH of less than 7.25 (with normal pCO2 levels) is 
another indication of terminal shock. 


[insert tables and captions] 


Table 3-2 gives normal and crisis values for blood gases and 
chemistries. Memorizing these values is essential for rapid 
assessment of a patient's status in a difficult emotionally 
stressful situation. The Transport Technician should commit 
these values to memory and review them frequently. 

Pulse Oximetry 

You should now understand that it's seldom easy to determine 
when a patient is going to experience cardiac arrest. 
Recently, a tool has come into use in the cryonics community 
which promises to objectify this process somewhat and 
provide a more reliable measure of when a patient is 
becoming frankly agonal by providing a very reliable 
indicator of the patient's overall perfusion status. 
This device is the pulse oximeter. It has a number of 
advantages over all of the assessment techniques described 
above. It is simple, accurate, noninvasive, painless, and 
easy to use, giving continuous information about a patient's 
pulse and perfusion status. The pulse oximeter consists of 
either two or three components: the oximeter module, a cable 
with sensor (which is applied to the patient), and if the 
unit is portable with internal, rechargeable batteries: it 
will have a separate power supply/charger!
. 


Figure 6-5: Pulse Oximeter: oximeter, photodetector, sensor 
placement. 


The sensor contains two diodes emitting red and infrared 
light which is picked up by a photodetector after it has 
passed through human tissue. In some pulse oximeters, the 
detector is placed opposite the emitting diodes, with an ear 
lobe or fingertip in between. In other units, the light is 
detected after it has penetrated tissue and reflected off 
internal bone, typically in the patient's forehead. 
Some units combine both modes of operation, to allow maximum 
flexibility of probe placement. This is especially important 
for cryonics purposes where poor perfusion may persist for 
many hours. In such cases, you should be able to use areas 
such as the bridge of the nose or the forehead, where 
perfusion usually persists until the very end. 

Regardless of whether the unit uses transmittance, 
reflectance, or both, it works on the principle that oxygen 
content will alter the light-absorbing characteristics of 
hemoglobin in the arterial blood supply. Thus, the pulse 
oximeter provides a reliable guide to arterial oxygen 
saturation, at the same time that it monitors the patient's 
pulse. 

Usually, there will be an alarm that can be preset to values 
for pulse rate and saturationa selected by the operator. 
There will be another alarm preset to values which cannot be 
overridden. 

In a terminally ill cryonics patient, assuming the patient 
and family are cooperative, pulse oximetry should be used as 
soon as possible and should be continued for as long as 
possible. There are no exceptions to this rule. Any patient 
who has been diagnosed as terminal is at increased risk of 
sudden cardiac arrest, and pulse oximetry enables a constant 
24-hour vigil. 

The importance of this cannot be overstated. Decompensation 
may occur suddenly, particularly in cases where the patient 
is elderly, has heart disease, has active orb potential for 
active bleeding, or has chronic obstructive pulmonary 
disease (such as emphysema or pulmonary fibrosis). The 
emergency can easily occur when no one is around or when a 
sitter or registry nurse has fallen asleep.
 
Similarly, younger patients who are at risk of sudden 
decompensation, such as those with heart disease, 
arrhythmias, electrolyte imbalance, or risk of bleeding 
(such as patients with gastric or esophageal tumor 
involvement) must be continuously monitored to avoid cardiac 
arrest occurring without advanced warning. 


Figure 6-6: Vital signs and pulse oximetery data in a 55-
year old male AIDS patient.  This patient was in peak 
physical condition 2-years prior to onset of his illness 
(runner/weightlifeter).  Note the extended period of time 
which these reserves allowed the patient to tolerate poor 
perfusion.

Pulse Oximetry Crisis Values 

You should become more vigilant when oxygen saturation drops 
to 90% or below. If the patient becomes agitated or is 
moved, this may result in false low saturation readings. 
However, they may also signal the onset of cerebral hypoxia, 
and you should take great care to do a complete evaluation 
including a pulse oximetry reading. 

As saturation declines below 80%, cardiac arrest is usually 
imminent (typically 24 hours or less), and changes in vital 
signs, mentation, and tissue perfusion will become more 
pronounced. 

Setting Up and Troubleshooting the Pulse Oximeter 

A variety of oximeters may be in use throughout the cryonics 
community in the coming years. For specific guidance, follow 
the manufacturers' instructions carefully. In general, 
however, the following guidelines should apply: 

Check the cable and probe.
 
Clean the probe with alcohol as recommended by the 
manufacturer. 

Change the site used for measurement every four to six hours 
as needed to reduce vasoconstriction and accompanying false 
"low" readings. (This will also reduce the chance of 
ischemic damage to the skin from compression by the probe or 
probe holder.) 

If the room is brightly lit, there will be a risk of false 
readings. Guard against this by covering the site where the 
probe is applied in such situations. 

Initially, if the patient finds forehead or earlobe 
monitoring uncomfortable or distressing, you can apply the 
probe to a finger or toe. As the perfusion status 
deteriorates, however, the patient's level of consciousness 
may diminish to the point where you can shift the probe to 
an ear lobe without causing undue distress. Ultimately, as 
even the ear lobe experiences diminished perfusion, the 
forehead or the bridge of the nose can be used. 

Caveats on Pulse Oximetry 

Perhaps the most important caveat to pulse oximetry is that 
it can only be effective if you use it. In fact, if you use 
the pulse oximeter inconsistently, this may create a false 
sense of confidence. Similarly, if the unit is not operating 
properly it constitutes a serious hazard. In the  complete 
absence of pulse oximetry, other methods of monitoring the 
patient will be used; but this will not be the case if you 
are placing your trust in the monitoring equipment. 

One final caveat is also in order. Pulse oximetry is not a 
reliable indicator of hypoxia or inadequate tissue perfusion 
in cases of severe anemia where the patient's hemoglobin is 
less than 8 g/100 ml. In such instances, hemoglobin oxygen 
saturation may be reported by the oximeter as adequate (as 
indeed it is), but the amount of hemoglobin available to 
deliver oxygen to the tissues is not adequate, and oximetry 
will not indicate the true state of affairs until very near 
the time of cardiac arrest (minutes to an hour). Thus, in 
cases of severe anemia, you must use other methods in 
addition to pulse oximetery to assess the patient's 
perfusion status. 

Similarly, in cases where the amount of abnormal hemoglobin 
(carboxyhemoglobin, methemoglobin or sulfhemoglobin) is 
greater than 3% to 4%, pulse oximetry will not be a reliable 
indicator. Increased bilirubin levels which occur in 
jaundice secondary to liver failure (a common occurrence in 
end-stage cardiac, cancer, and hepatic disease patients) can 
also cause false readings, indicating low saturation. 
Saturation may also be "falsely" depressed in cases of 
peripheral vascular disease or when vasoconstricting 
medication is being used. 

Graph Your Data

Taking all the readings and gathering the data as outlined 
above is important and is the first step.  However it is of 
only limited usefulness unless the data is presented in a 
way that lets you spot *trends*.  Thus it is very important 
that you graph data in real time.  Heart rate, blood 
pressure (preferably as mean arterial pressure (MAP)) 
respiratory rate and mixed blood oxygen saturation should 
all be plotted graphically, preferably on the same sheet of 
graph paper.  This will allow you to spot trends early and 
being making preparations.  

Study the graphics of the two patients' agonal vitals 
presented in this chapter.  In both cases trends were 
important.  In one case (patient A-1049) the trend of 
increased heart rate and steadily dropping blood pressure 
was highly predictive.  This is almost a textbook case; when 
the patient's systolic blood pressure dropped below 50 mmHg 
she expired very shortly thereafter.  Maintaining a graphic 
record can tip you off to the beginning of the final spiral 
of decompensation precious hours before you might have 
noticed it otherwise.

A Final Note 

Generally, shock is not tolerable for more than a few hours, 
particularly in chronically ill and debilitated patients. 
You should rely on nursing staff to assess whether a patient 
is experiencing shock and how much time may remain until 
cardiac arrest. 

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