Chapter XX (2)

Morphine offers no little aid in the production of anesthesia in many cases. Those patients who are terrified by the thought of operation, and who are in a semihysterical state when anesthesia is begun, may be greatly tranquillized by a hypodermic injection of 0.01 to 0.015 of morphine, fifteen or twenty minutes previously. Given in this way it acts as a heart tonic and general equalizer to the circulation. If a small dose of atropine be added the effect upon the respiratory centres is much enhanced. Again, in those cases where anesthesia is begun without it, and patients prove very rebellious, it will have the same happy effect. The only objection to its use is the nausea which may thereby be produced. There is no way by which to dissociate this from the nausea due to the anesthetic, elsewhere considered under the heading of the After-care of Patients.

Patients can rarely be so completely put under the influence of morphine as to justify its use alone.

=Scopolamine.=--The Germans sell under this name an alkaloid made from the Solanaceæ, which seems to be identical with the _hyoscyamine_ of the U.S. Pharmacopœia. Schneiderlin, in 1900, published a method of producing anesthesia with little discomfort by using it combined with morphine. The mixture seems more effective than either alkaloid alone, but is rather slow in action. On the day preceding the operation a trial dose of 0.02 of morphine and 0.008 to 0.01 of scopolamine may be given. This will demonstrate the susceptibility of the patient to the mixture. One hour and a half before the operation this dose, or a larger one, should be administered, and, if necessary, another one of smaller size fifteen minutes before the time of operation.

According to this method an interval of sixty to eighty minutes should elapse between the first dose and the operation itself. When anesthesia is thus produced it lasts from three to several hours. Others have advised to divide the dose into three injections, giving the first about two and one-half hours, the second one and one-half hours, and the third one-half hour before operating. In some cases this has produced complete and satisfactory anesthesia; in some it has not been complete, while in others serious symptoms have been produced. The statement that each alkaloid counteracts the dangerous effects of the other is not substantiated; it is probable that the combined effect is greater than would be that of either used alone. This mixture should rarely be used, save in those cases where general anesthesia is inadvisable, and where there are difficulties, even about the employment of local anesthetics.

LOCAL ANESTHESIA.

The use of ethyl chloride, as the most volatile of the ordinary drugs, by which chilling or freezing of the skin may be produced, has been already mentioned. Other agents which chill or freeze may be used, _e. g._, a spray of common ether or of rhigolene, or the local application of ice and salt.

=Liquid Air.=--Liquid air, when available, affords an excellent means of benumbing sensibility, since one or two very light applications, two or three minutes apart, admirably serve the purpose. It is, however, rarely available and should be used with great caution.

=Cocaine.=--Of the local anesthetics _cocaine_, or some of its compounds or substitutes, will give the best results; although it is said that injections of pure water, if sufficiently bulky, will also answer the purpose of a local anesthetic. Cocaine has marvellous properties upon mucous surfaces or in the tissues, but none upon the unbroken skin. Where the parts to be operated are covered with skin it is necessary to inject the drug with a hypodermic syringe, as in the case of all deeper tissues. About the eye, the drug is used in from 1 to 4 per cent. strength; in the nasopharynx, from 2 to 4 for ordinary purposes; about the genitals, 2 to 5 per cent.; beneath the skin, ordinarily in strength of 1 to 2 per cent. In operations upon the nasopharynx and larynx it is often advisable to make a local application of a small amount of an almost saturated solution, by which a more complete effect is gained.

_Cocaine is not without dangerous toxic properties_, to which some persons are peculiarly susceptible. It will seriously disturb heart action in some; in others produce vertigo and mild delirium, and in still others peculiar erotic symptoms. Warm solutions are more quickly absorbed than cold ones. The use of more than 0.06 (1 grain) should be avoided.

When the skin alone is to be anesthetized the injection should be made into and not beneath. The nearer the cocaine solution is deposited to the principal nerve trunk or branches the more promising will be its effect.

The use of cocaine in operations, under general anesthesia, for the prevention of those depressing influences which cause lowered blood pressure and shock, has been alluded to in the chapter on Shock. For instance, it is well to spray the larynx after opening it and before making further operation upon it; while in all major operations in which large nerve trunks are exposed or divided, _e. g._, amputations, etc., the injection into the nerve trunks of a few drops of 2 or 3 per cent. cocaine solution prevents this kind of disturbance.

For small and localized operations the direct injection of cocaine into and around the area involved will prove sufficient. It is rarely necessary to use for this purpose a solution stronger than 1 or 2 per cent., especially if it is deposited drop by drop around the entire margin of the area and if the part have been previously made bloodless by pressure, as by the Esmarch rubber bandage. But when extensive operations are to be undertaken the method of “_blocking_,” so called, should be carried out. This consists in cocainizing the principal nerve trunks which supply the part, for which purpose an accurate knowledge of regional neural anatomy is necessary, with the intent to inject into or closely around the nerve trunks a few drops of a 1 or 2 per cent. solution. Working in this way by combination of injection, then of incision, by which the nerve trunks are better exposed and more fully protected in order to be more completely injected, and then proceeding farther with the operative part, extensive operations have been and may be done; such for instance as amputations, not alone of the limbs but even of the shoulder girdle, removal of large tumors, etc. In this way, for example, Kocher now removes most of the goitres which he attacks. The essential feature of this work is to first get the cocaine inside of the nerve sheaths. In this way a minimum of the drug is used with a maximum of effect. Nevertheless when a large nerve trunk is thus to be paralyzed temporarily it is best to inject the solution directly _into it as well as around it inside the sheath_. Cocaine is a temporary protoplasmic poison, and for the time being shuts off the afferent power of the nerve. One advantage of this method is the avoidance of shock as well as of pain. Another method, devised by Schleich, is to be preferred. He uses three different solutions, of which the second is commonly used. Tablets for making these solutions can now be obtained. In order to secure the best effect with them the parts should be made bloodless. The solution is deposited subcutaneously in a series of drops around the margin of the area, and then massage may be made to distribute the fluid more uniformly in the tissues. When the tissue to be operated upon is inflamed the injections should be made first into the healthy area on the proximal side.

Schleich’s formulas are as follows:

No. 1.
Cocainæ hydrochloridi .200 (gr. iij).
Morphinæ hydrochloridi .025 (gr. ²⁄₅).
Sodii chloridi .200 (gr. iij).
Aquæ destillatæ ad 100.000 (f ℥ iiiss).

No. 2.
Cocainæ hydrochloridi .100 (gr. iss).
Morphinæ hydrochloridi .025 (gr. ²⁄₅).
Sodii chloridi .200 (gr. iij).
Aquæ destillatæ ad 100.000 (f ℥ iiiss).

No. 3.
Cocainæ hydrochloridi .010 (gr. ¹⁄₆).
Morphinæ hydrochloridi .005 (gr. ²⁄₅).
Sodii chloridi .200 (gr. iij).
Aquæ destillatæ ad 100.000 (f ℥ iiiss).

Various substitutes for cocaine are now on the market. Some of these are soluble and some insoluble. _Eucaine_ is most commonly used, especially in form known as _eucaine B._, or _beta-eucaine_. It is weaker than cocaine, especially so in toxic properties, and solutions of twice the strength can be used, often with satisfaction, and almost always without danger. For urethral and eye work, _e. g._, it answers the purpose; nevertheless, it will sometimes prove disappointing. _Orthoform_ is a crystalline, sparingly soluble artificial product, which is too light and too coherent to be generally serviceable. It often gives satisfaction mixed with other powders or in ointments, and it is usually free from toxic properties. _Nervanin_ is another laboratory product, not equal in activity to cocaine, but almost free from unpleasant properties. _Anesthesin_ is another similar product, which is practically free from physiological properties save that it acts as a local anesthetic. The latter may be employed for infiltration anesthesia in the following proportion, recommended by Dunbar:

Anesthesin hydrochloride 0.250
Sodium chloride 0.150
Morphine hydrochloride 0.005 to 0.015
Water 100.000 Cc.

_Stovaine_ and _alypin_ are among the latest synthetic substitutes for cocaine. The latter seems to offer promise of usefulness.

Adrenalin may be added to any of these solutions in proportion of 1 per cent. of a 1 to 1000 solution, and will have a beneficial effect in all cases.

INTRASPINAL COCAINIZATION.

The intraspinal injection of remedies was first suggested by Corning, of New York, in 1885; it remained, however, for Bier to perfect the technique in 1899, and to make it so popular that the same maneuver has been practised for various other purposes; as, for instance, for withdrawal of cerebrospinal fluid in cases of hydrocephalus, etc., or the injection of tetanus antitoxin. (See chapter on Tetanus.)

The intent in this use of cocaine is to spread the solution over the surface of the cord and beneath the arachnoid. For this purpose a needle about 4 inches in length, with a point not too sharp, preferably gold or platinum plated, is used; with this also a syringe which will hold 2 to 4 Cc., which can be firmly, yet easily, attached to the needle. The accompanying illustration (Fig. 46) will give an idea of the technique. The patient should be seated leaning forward so as to curve the back and open the intervertebral spaces. A sterilized towel is stretched tightly across the back from one iliac crest to the other; its upper edge should then pass just over the spinous process of the fourth lumbar vertebra. The injection is usually practised between the second and third lumbar spines, or between the third and fourth; the latter having been identified, the former are easily made out. The needle is entered about 1 Cm. to the right of the middle line and passed forward, inward, and upward, to a depth of 7 or 8 Cm. in the ordinary adult, until the resistance offered by the tissues is felt to have been passed and the point to have entered a cavity. If the needle has been passed alone the escape of a drop or two of cerebrospinal fluid will indicate that the spinal canal has been entered; if the syringe is attached to the needle the piston should be withdrawn in order to show the same result. It is possible to practise this operation with a patient in the recumbent position, but it is done more easily as above outlined. The skin may be frozen by the freezing spray, or may be anesthetized by the local injection of cocaine solution with the ordinary hypodermic syringe.

It is astonishing what beneficial effects can be gained from the use of a small amount of cocaine. It is rarely necessary to use more than 0.03 (¹⁄₂ grain) of pure cocaine in order to procure analgesia of the entire lower part of the body.

_Beta-cocaine_ or _tropacocaine_ may be used for the same purpose, in double this amount, but they do not give as reliable results. Morton, of San Francisco, has suggested that ¹⁄₂ Gr. powders of cocaine be wrapped in such a way that they can be repeatedly sterilized by a heat of 200° F., and that one of these be dropped into the syringe barrel, that this be attached to the needle, and the cocaine itself be dissolved in the cerebrospinal fluid withdrawn through the latter, and then thrown back again. This is probably the neatest and most serviceable method yet devised, and its originator has assured the writer that with 1 Gr. of tropacocaine used in this way, thrown into the spinal canal with considerable force, _i. e._, in such a way as to more completely distribute it, he has been able to practise operations even upon the tongue with little or no pain to the patient. The solution used for this purpose should be sterilized, also the needle, the syringe, the patient’s skin, and the operator’s hands. The water with which the cocaine solution is made should be first pure, then measured, and the solution made in such strength that not more than the amount indicated above will be used. This should then be again heated, but not quite to the boiling point, since cocaine solutions are impaired by too much heat.

Technique of intraspinal injection.]

The advantages of intraspinal anesthesia are many and obvious, and were it not for disadvantages this method would have supplanted all others for certain work. It is, however, by no means free from danger, both from the maneuver and from the drug itself. Carelessness in its introduction may lead to septic meningitis, while the drug itself may produce considerable and even serious or fatal disturbance, though these cases are rare. It has been claimed that 2 per cent. of the cases in which this method has been employed have, in consequence, terminated fatally. The immediate effects are largely confined to the stomach and the nervous system, and include nausea, intense headache, and profound depression. The remote effects are less positive, but have been stated to include serious changes in the cord itself. It is often a disadvantage to have the patient mentally conscious of what is going on, even though oblivious to pain. Inasmuch as cocaine produces analgesia rather than anesthesia, nervous patients will be likely to mistake the general sensation of lifting a limb, or manipulating it, for actual pain. There are not a few cases where chloroform and ether are so plainly contra-indicated that if it were possible to use any other agent with safety this would offer a valuable substitute.

The effect desired is not produced immediately, but comes on slowly, after the expiration of ten to twelve minutes. As ordinarily used, anesthesia of the surface will be produced up to the height of about the waist. Should it be desired, however, to increase or enhance the effect the solution might be injected between some of the dorsal vertebræ, although at this point it will require more skill to introduce the needle, and the operator should be cautious not to injure the cord. Below the second lumbar vertebra the cord breaks up into its segments and the patient would be almost exempt from this danger. It is occasionally necessary to tranquillize the patient’s fear by using morphine subcutaneously at the same time. It is a question whether this can be safely combined with cocaine for the subarachnoid injection. Failing in this it may be necessary to supplement the use of cocaine with ether or chloroform.

The intraspinal injection of normal saline solution, or even of pure water, has been shown by Eden to be almost as effective in some cases as the cocaine solutions. Bier has largely modified his statements about the value of intraspinal cocaine injections, and speaks of them as more dangerous than he had first appreciated.[11]

[11] _Magnesium Salts as Local Anesthetics._--Six years ago Meltzer
discovered that magnesium salts have the property of inhibiting
functional activity in nerve tissue, and in December, 1899, he
announced that the intracerebral injection of magnesium sulphate
in a rabbit caused paralysis without previous convulsions. He has
recently announced the local anesthetic effect of small doses of a
25 per cent. solution of magnesium sulphate, an effect which lasts
from one to two hours. It is the magnesium “ion” which possesses the
anesthetic property, since the chloride and the bromides give the
same effects.

These salts have this advantage over other local anesthetics that
there is no primary period of excitation. Moreover, applied locally
to nerve trunks they have the effect of “blocking” them; and when
applied to the sciatic, pneumogastric, and other nerves, temporarily
abolish their power of conducting influences, either motor or
sensory. This effect is apparently due to the fact that the magnesium
normally present in the tissues constantly exercises an inhibitory
power over them, and that when thus applied from without they merely
exaggerate the condition already present; thus, if this be true,
affording an ideal anesthetic.

In December, 1905, Meltzer read a paper before the New York Academy
of Medicine, announcing success with intraspinal injection of
magnesium sulphate in 25 per cent. strength. Blake, of New York,
promptly made use of the suggestion in a child with tetanus. Two
injections of antitoxin had been made into the cervical cord on
successive days, with apparently no effect. He then made lumbar
puncture and a subdural injection of magnesium sulphate, giving 1 Cc.
of 25 per cent. solution for every twenty-five pounds of body weight,
administering it every thirty-six hours, employing four doses. The
effect was marked, in immediate control of convulsions, which,
however, was not permanent; hence the repetition of the doses. How
much influence the previous antitoxin had produced does not appear.

Meltzer suggests that the best time for an operation is three or
four hours after a spinal injection. He reports four cases thus
operated, in one of which, after the operation, the patient passed
into a period of deep general anesthesia, in which he remained for
five hours, the pulse keeping up, the respirations falling to ten
per minute. In this case another spinal puncture was made, some of
the spinal fluid let out, and the spinal cavity treated by repeated
irrigations with sterile salt solution.

Meltzer’s few but important experiences indicate that at least three
or four hours should be allowed to elapse after the introduction of
the magnesium solution. He advises 1 Cc. for every twenty-five pounds
of body weight, for intraspinal injection, which causes not only
_analgesia_ but temporary paralysis of the legs, sensation and motion
returning in from eight to fourteen hours, with possible retention of
urine for a day or two, requiring the use of the catheter.

Doses a little larger than the above, he thinks, would permit the
performance of extensive operations in the abdominal cavity, or even
higher up, without the aid of a general anesthesia. He is inclined
to think that it would be preferable not to wait four hours, but
to operate within about two hours after injection, with the aid
of a small amount of chloroform, the operation to be followed by
another puncture, with the removal of at least as much fluid as
was introduced, and irrigation with sterile salt solution, finally
leaving some of it within the canal.