THE CLINICAL OBSERVATION OF THE PATIENT.
Stages of Anæsthesia.
Anæsthesia has been divided into four clinical stages corresponding
to the degrees to which the nervous system has been affected. The
boundaries between these stages are often ill-defined, but the
terminology has some value as facilitating description.
THE FIRST STAGE lasts from the commencement of inhalation up to the
time when volitional self-control is lost by the patient.
THE SECOND STAGE in the older text-books was said to be characterised
by struggling, shouting, and breath-holding. With a patient not
addicted to alcohol and with the anæsthetic skilfully administered,
this description is unduly lurid.
THE THIRD STAGE is that of full surgical anæsthesia.
THE FOURTH STAGE is that of over-dosage.
The Ocular Reflexes in Anæsthesia.
These give such valuable assistance to the anæsthetist that it will be
well to define and describe them as a preliminary. They are three in
number.
THE CONJUNCTIVAL REFLEX is best elicited by drawing the upper lid
upwards from the eyeball and retaining it in that position with one
finger, while with another finger the ocular conjunctiva is lightly
touched in the area of the inner canthus. If the anæsthesia is very
light, both lids attempt to approximate and close the palebral
fissure. The upper lid may slip down from under the retaining finger
and come into its proper place, while the lower lid is elevated. At
a deeper level of anæsthesia there is not complete action of the
orbicularis but merely of a certain part of it, so that all that is
observed is a _twitch inwards of the lower lid_. Even this form of the
reflex disappears before the corneal reflex.
THE CORNEAL REFLEX is elicited by pushing up the upper lid by one
finger and with the pulp of the _same_ finger lightly brushing the
centre of the cornea as soon as it is exposed, when we feel or see the
upper lid come back into position with a sharp definite twitch. The
examining finger must be slipped smartly out of the way as soon as
the cornea has been touched. Even in deep anæsthesia, a trace of this
reflex can usually be elicited if the little manipulation be properly
performed.
The conjunctival and corneal reflexes are frequently confused in the
mind of the student. The most common mistake made is to pin the upper
lid firmly somewhere in the region of the bony roof of the orbit,
to dab the eye far too vigorously, and to believe that no reflex is
present because no movement of the upper lid takes place. In the first
place, the upper lid cannot move if it is rigidly held against a bony
plate: in the second place, it is wholly unnecessary to inflict upon
the cornea more than the lightest of touches. Both these reflexes
are to be used with great discretion, undue frequency and excessive
vigour of touch being alike capable of setting up serious inflammatory
reaction.
THE PUPILLARY LIGHT REFLEX is elicited by shutting off light from
_both_ pupils for ten to twenty seconds and then smartly withdrawing
the protecting fingers and allowing as strong a light as possible to
fall on to the eye. The response of the ciliary muscle should _always_
be present; its absence is a certain indication of something wrong:
some sluggishness may be permissible under ether, but even that is
suggestive of trouble if chloroform is the anæsthetic.
The use of a preliminary hypodermic of morphia tends to make the pupil
somewhat smaller than normal, and to elicit the light reflex it may be
necessary to cut off illumination for a somewhat longer period than
if no morphia had been given. Nevertheless with a little care, the
light reflex should always be capable of demonstration even in the
morphinised subject.
The Observation of a Normal Case.
In the case of nitrous oxide and of ethyl chloride, the patient passes
through the various stages very rapidly, and the picture of anæsthesia
as induced by either of these two is therefore best described
separately. The following may be taken, therefore, as an account of
what is to be observed in the patient inhaling ether or chloroform,
unless a specific reference is made to one of the other anæsthetics.
FIRST STAGE.--The first sign that some effect is being produced in the
patient is usually the appearance of the movements of _swallowing_;
the hyoid and thyroid can be felt or seen to be moving in conjunction
with the muscles of deglutition. During this stage, the patient being
still to some extent under volitional control, there should be no other
movement noticed. The eyes are usually closed and the colour normal;
the respiration may be hurried by excitement, but judicious handling of
the patient will do much to minimise this.
THE SECOND STAGE is really entered when volitional control is lost.
It may be characterised by struggling and shouting by the patient,
even if the anæsthetic is properly administered; but with a healthy
patient and a good anæsthetist, all that usually occurs in the way of
movement by the patient is some rigidity of the limbs and a slight
attempt, perhaps, to lift the head from the pillow or a limb from the
couch. The breathing tends during the first part of this stage to be
light and is rarely entirely regular: slight pauses occur, usually
after an inspiration, less commonly after expiration. Serious “holding
of the breath” (after an inspiration) rarely occurs save in the type
of patient who is also struggling; if it does occur to a degree which
causes any blueness of the patient’s face (cyanosis), it usually calls
for the removal of the anæsthetic for a moment until normal breathing
has been resumed.
The colour of the face rarely departs much from normal during the
second stage, unless cyanosis from breath-holding intervenes.
The eyes are usually opened, as the second stage progresses, and the
eyeballs tend to rotate slowly in every plane. The pupils are usually
large, but react sharply to light. Both conjunctival and corneal
reflexes are brisk.
THE ONSET OF THE THIRD STAGE is marked by the appearance of muscular
relaxation. Any limb which the patient may have been holding rigidly
up sinks down on to the couch, and it will be found that if an attempt
be now made by the anæsthetist (as it should be) to turn the head of
the patient to one side or another, the muscles of the neck no longer
resist.
_The respiration_ also alters in type, losing its tendency to lightness
and irregularity, and becomes full, deep, and regular. In open ether
anæsthesia particularly, expiration commonly assumes a “blowing” type
very characteristic, and which to the trained ear is of itself an
indication that full surgical anæsthesia is present or at any rate not
far distant.
_The colour_ varies somewhat with the anæsthetic in use. With ether it
is usually somewhat higher than normal, and a trace of blueness may
be present if the method is the “closed” one. Anything more than a
trace, however, must be regarded as abnormal, whatever the method or
anæsthetic may be. With chloroform the colour is perhaps a little paler
than that normal to the individual.
_The eyelids_ are usually half open, and the eyeballs at rest looking
forward and slightly downwards. An extreme rotation downward may
usually be taken as a sign of very deep anæsthesia. _The pupil_ is, as
already said, always active to light, but its actual size varies with
the anæsthetic used. With ether, particularly “closed” ether, it may be
large (4–5 millimetres): with open ether, preceded by morphia, about
3–4 millimetres: a good chloroform anæsthesia usually exhibits a pupil
of only 2–3 millimetres, and if morphia has also been given, it may be
pin-point in size. Too much emphasis must not be placed, however, upon
the mere size of the pupil; that may vary within wide limits without
necessarily indicating serious abnormality. The essential point is that
the light reflex shall be brisk. A pupil of 5 millimetres reacting
sharply to light may be of no special moment: one of that size immobile
to light would cause real anxiety.
_The conjunctival reflex_ usually disappears fairly early in the
third stage: if briskly present, the anæsthesia is certainly a light
one, and probably insufficient for an abdominal section. _The corneal
reflex_ if properly taken in the way already described can usually
be elicited throughout the third stage. In an anæsthesia deep enough
for abdominal section it is, of course, not brisk, but we may say
generally that its entire absence is _presumptive_ evidence of a very
deep anæsthesia--probably undesirably deep. It must not be forgotten
that some local causes such as drying of the surface of the cornea
may cause it to disappear, and in case of doubt it is sometimes worth
while to wash out the eye with a little saline solution. If after doing
so the anæsthetist still finds the reflex not present he should be on
his guard. Provided, however, that the light reflex is still present
and colour and respiration satisfactory, he need not consider that the
patient is in any immediate danger.
Broadly speaking, then, the third stage, the stage which is called for
by the requirements of major surgery, is characterised by (1) full
regular respirations; (2) colour not much removed from normal; (3)
moderate sized pupil, larger in the case of ether than chloroform; (4)
conjunctival reflex faint or absent; (5) corneal reflex just present,
or, in a deep third stage, just absent; (6) light reflex present: these
may be regarded _as the signs of fully developed surgical anæsthesia_.
The absolute beginner may be so completely out of his reckoning as
to mistake the quietude of the later part of the first stage for the
appearance of the third stage. For the prevention of so gross an error
as that, the reader need only be referred to a patient study of the
foregoing. But even a man with considerable experience may frequently
be in doubt exactly as to _how far through the third stage his patient
has passed_. He may have attained a level which will permit an incision
to be made into the skin without movement on the part of the patient,
but not one which would relax the abdominal muscles sufficiently for
the peritoneum to be opened without eliciting considerable resistance
from the abdominal muscles. In such moments of doubt, the author is
accustomed to request the surgeon to make his skin incision, and
_observe the effect which this trauma has upon the depth, frequency,
and regularity of respiration_. This furnishes a most valuable guide
to the depth of anæsthesia. In a third stage of very light degree, the
respiratory rhythm will be interrupted and the breath held for a second
in inspiration. Apart from any other sign, that may be taken as an
index that the anæsthesia is very light--too light to permit of opening
the peritoneal cavity. In a very deep anæsthesia the respiration
is little affected by the skin incision, while at a moderate and
more desirable level the respiration is quickened and deepened, but
unaffected in the regularity of its rhythm.
THE FOURTH STAGE IS STAGE OF OVER-DOSE.--This stage is, of course,
never entered voluntarily. Its earliest signs are loss of all tone in
the muscles of expression, complete loss of corneal reflex, a widely
dilated pupil _insensitive to light_, and a type of respiration which
though definitely weakened may show occasional deep gasps. Circulatory
failure and cessation of respiration from failure of the medullary
centre are the closing phenomena of overdose.
The Circulation in Anæsthesia.
It will be perhaps noticed that in the foregoing, no reference has
been made to the examination of the pulse. This is not an oversight on
the part of the author. It is perfectly true that under any anæsthetic
not complicated by an asphysical element, the blood pressure falls as
the drug takes effect, and that in the case of chloroform the fall is
often quite considerable. Such a fall can be appreciated by the skilled
finger, but only by concentrating upon that examination a degree of
attention which necessarily detracts from the administrator’s available
energy for the observation of other signs which are of equal value, and
can be more rapidly and certainly appreciated and appraised.
It is nevertheless essential to assure oneself during the whole
progress of an anæsthesia that the circulation is in a satisfactory
condition. Two obvious guides to this are the colour of the patient’s
face and the force with which cut arteries spout. As regards the colour
in circulatory failure, one would naturally expect a pallid face, and
this indeed is the rule. It must not be forgotten, however, _that
cyanosis may sometimes be cardiac in origin_. Cases do sometimes occur
when a bluish tinge is seen on the lips, ears, and nostrils, apart from
any obvious cause of oxygen starvation. In these we may reasonably
suspect that the right heart is failing, and take measures accordingly.
Another valuable index to the state of the circulation is the “skin
reflex,” that is, the speed with which the circulation returns to an
area of the skin which has been pinched. The student should train his
eye by occasionally pinching the lobule of the patient’s ear and
observing first the white area so produced, and later the rate at
which, in a normal case, the healthy colour returns.
Abnormal Phenomena in Anæsthesia.
It is not intended to furnish here any account of matters more suitably
treated under the “Accidents of Anæsthesia,” which are fully described
in Chapter xvi., but merely to draw the attention of the student to
certain departures from the normal course of anæsthesia which are
encountered with varying frequency, to ascribe them as far as possible
to their true causation, and indicate methods of prevention.
The abnormalities fall into two classes, those connected with the
nervous and muscular systems, and those in which respiratory changes
are evident.
MOTOR AND NERVOUS SYSTEM.
_Clonus or tremor_ sometimes appears in one or more limbs, even the
trunk being affected in severe cases. Ether is practically the only
anæsthetic under which the tremor ever appears, and the condition is
often spoken of as “ether tremor.” It rarely appears in the female
subject, being almost limited to powerfully built young men. Coming
on towards the end of the second stage, it frequently persists in the
deepest of third stages, and in bad cases there is usually no option
but to change over to chloroform--always supposing that the tremor will
interfere with the work of the surgeon. If it will not, the condition
calls for no active treatment, since it is in itself not dangerous.
_Movements recalling to the observer the condition of athetosis seen
in the limbs of hemiplegics_ are occasionally seen in the anæsthetised
patient. The fingers of a hand may be slowly moved, or one or other
shoulder may be shrugged. The exact cause of these movements is
obscure. They occur in all types, both sexes, and at all ages; they are
not necessarily asphyxia though a trace of asphyxia seems sometimes
to conduce to them. They persist for some time after the third stage
has been entered, and ultimately disappear without any obvious cause
other than the passage of time. It is rare for them to continue more
than five or ten minutes after full anæsthesia has been induced. Their
practical importance lies purely in this, that the inexperienced
anæsthetist observing some muscular movements still persisting, may
take them as an infallible sign that anæsthesia is not complete, and
may deliberately take his patient to a deeper level. If in doubt, the
anæsthetist must, of course, consult all the other recognised guides,
such as the eye reflexes, but once he has seen these movements in a
case, and had demonstrated to him _their slow, rhythmical character_,
he is not likely to be misled on a future occasion.
_Muscular rigidity_ has been mentioned already in Chapter iii. When
it persists in a patient in whom other signs suggest that a full
anæsthesia has been produced, the anæsthetist will usually find that
attention to the air-way, and perhaps a whiff of oxygen, will remedy
the trouble.
Respiratory Abnormalities.
_Shallow breathing_ or even slight temporary arrests of
respiration arise frequently. During the induction stage they may be
due to:--
1. Apnœa or acapnia following voluntary excessive breathing.
2. Using morphia before chloroform.
At a later stage, it may be due to:--
1. Acapnia following excessive breathing excited reflexly from
the seat of operation.
2. Direct reflex inhibition of the respiratory centre.
An example of this is seen sometimes when the bladder is
over-distended by lotion.
3. Impending vomiting.
_Moist sounds_ not uncommonly appear. The student’s general knowledge
of medicine will enable him to decide whether the fluid is likely to
be in the pharynx, larynx, trachea, or bronchi. If in one of the first
two named, it will suffice to swab out the throat and encourage the
patient to cough. If, however, moisture is evidently present in the
trachea or bronchi, the condition is one calling for considerable care
and judgment. It arises more commonly with ether than with chloroform.
Much will depend upon how much longer the surgeon requires to finish
his operation. If only a few minutes more are required, nothing is
necessary but to cut down the amount of ether being given to the
minimum possible. If, however, the surgeon has still a good deal to do,
the safest thing is to withdraw the ether and substitute chloroform
or a mixture. Be it clearly understood, however, that such a change
over is not devoid of risk. If it is to be made, it must be done
early, before the patient is cyanosed and almost drowned in his own
secretion. In a neglected case where cyanosis has already appeared,
there will be no option but to interrupt the operation, empty the chest
by encouraging coughing, and to aid the process by compressing the
patient’s chest during expiration. Thereafter chloroform may be given,
but with the greatest care.
_Gasping and sighing_ are not common phenomena but when they occur,
call for close notice from the anæsthetist. Excluding, of course, such
occurrences in the first stage, before volitional control has been
lost, they may be _usually but not invariably ascribed to overdosage
or to the appearance of definite surgical shock_. Whenever they are
noticed, therefore, it behoves the administrator to overhaul the
patient thoroughly, to consult the eye reflexes, the skin reflex, and
the pulse, and not to rest until he is assured that there are no other
signals of danger to be found.
_Stertor and stridor._ The first of these is caused by flapping of the
soft palate. It is a noise low in pitch, resembling ordinary snoring.
Indicating as it does that the palatal and therefore probably other
muscles, are relaxed, it may if moderate in volume usually be taken as
a favourable sign. If it becomes very loud, however, the probability
is that the base of the tongue has fallen back; cyanosis will begin to
appear, but will immediately be remedied by pulling forward the jaw or
in extreme cases, using the tongue forceps.
_Stridor_ is a high-pitched sound produced by approximation of the
vocal cords. It has already been dealt with in Chapter iii.
False Anæsthesia.
This term has been applied to a condition often seen in children,
and occasionally in adults. It is almost limited to chloroform: the
author has never seen a genuine case when ether has been in use. It
appears very quickly after inhalation has begun: the muscles are
relaxed, the respirations quiet and regular, the conjunctival reflex
sluggish. A very marked feature is the excessive smallness of the
pupil. Obviously then, the condition much resembles a true third stage,
but if the operation be begun, the mistake will very rapidly be made
evident, for the patient will at once move and cry out. In essence, the
condition is simply one of ordinary sleep. It can be recognised by its
appearance after a period of inhalation too brief for the induction
of true anæsthesia, by the very small pupils and the lightness of the
respiration. It will be a waste of time to permit the condition to
continue, as the lightness of the respiration delays the taking in of
a dose of the anæsthetic sufficient to induce a proper third stage.
The remedy is simple,--rub the lips and face smartly with a towel or
the hand, when respiration will at once deepen and the pupil dilate.
Thereafter, the induction should proceed normally.