Part 3

The respiration is studied by watching the movements of the chest or abdomen, by placing the hand in the vicinity of the nostril to feel the respiratory current of air, or, best of all, for the respiration is rarely noiseless, by listening to the breathing. The quality of the breathing is noted. The faintest indication of a snoring respiration means that the surgical degree has been reached. Any change in the quality of the breathing compels the questions “Has the patient escaped from the proper surgical plane?” “Is the anesthesia too deep or too superficial?” or “Is the change simply a respiratory reflex induced by the surgeon’s manipulations?”

The color of the ear is a most useful guide. This does not hold good of the color of the forehead. The forehead in some individuals becomes cyanotic with slight changes of posture. The ear is not so subject to postural influences and is therefore a less misleading indicator of the venous condition of the blood. Even a slightly bluish tinge of the ear demands attention. Usually, crowding is the cause, and a little more air allows the normal red flush to return. Slight pallor developing during the course of the narcosis should always be regarded as a danger sign. It means that the patient is in profound anesthesia, and that the heart is threatening collapse. The mask should be removed promptly and the patient allowed to breathe pure air. As long as the pulse is not weak or irregular one need not worry about the outcome.

There are some advantages in choosing the temporal pulse as the guide, instead of the radial pulse, which is ordinarily followed; occasionally the temporal can still be felt when the radial has become impalpable. The pulsation of the temporal artery is best felt by placing the index finger flat over the tragus into the depression at the root of the ear. The pulse is important because it tells how the heart reacts towards the anesthetic and the surgeon’s manipulations. The frequency is not very important. Exceptionally, it may be 120 or 130 during the greater part of an anesthesia without vital significance, if the quality is good. A diffuse and weakening pulse is a signal that the narcosis is too profound and that the heart is in danger of collapse. A somewhat irregular pulse may immediately precede or accompany the act of vomiting, and it is not a cause for alarm.

Accessory to the respiration, color and pulse, but of lesser significance, are the pupil, the cornea and eyelid, and the secretions.

In patients who have not received morphine before narcosis the pupil is, as a rule, a guide of some importance. If the pupil is narrow, examination of its reaction to light is generally superfluous. A wide pupil, however, often means one or the other extreme of narcosis. A wide pupil which reacts promptly to light indicates superficial anesthesia; the patient may need more of the anesthetic. A wide pupil which reacts to light sluggishly or not at all means that the danger line has been overstepped; the anesthesia is too deep; the patient must have air. Without knowledge of the reaction, every markedly dilated pupil should be looked upon as prognostic of danger.

To touch the cornea repeatedly with the finger for the purpose of obtaining the corneal reflex, is a bad habit. The reflex can be tested just as satisfactorily by shifting the eyelid gently across its surface.

A point worth remembering is that in the morphine-anaesthol (or morphine-chloroform) anesthesia the corneal reflex may remain quite active, while with ether it soon becomes feeble or extinct.

A useful indicator of the degree of muscular relaxation is, I believe, the tonicity of the eyelid. The usual arm test is very misleading. Flexing the elbow once or twice may give the impression that the muscles are thoroughly relaxed, and yet, on repeating the manipulation five or six times one may be surprised to obtain a sudden, powerful contraction of the biceps, showing that the patient is still not fully under the influence of the narcotic.

Normally the upper lid has a certain tonicity. If it is lifted gently by means of the superimposed ball of the finger it springs back to its natural position promptly. When the patient is fully under the influence of the anesthetic, this tonicity is partly or completely lost and the lid returns sluggishly to its natural position, or not at all. The patient can sometimes be kept in a proper surgical plane by giving a few drops of the anesthetic each time as the tonicity returns, and ceasing when relaxation of the eyelid is obtained.

When the patient is under anesthesia to the surgical degree the activity of the salivary, sweat and tear glands ceases. The accumulation of mucus in the mouth, the appearance of a tear in the eye, beads of perspiration on the brow all mean that the anesthesia is becoming superficial, that more anesthetic is required. It is worth bearing in mind that these indicators of the depth of narcosis do not, in all individuals, react in exactly the same way. While initiating the narcosis the anesthetist can get his bearings in regard to this point, and watch for any individual idiosyncrasy which may exist.

It is unsafe to concentrate the attention on one sign, lest the general aspect of the patient be overlooked.

The anesthetist watches constantly the rhythm and quality of the breathing, the color of the ear and the character of the pulse. From time to time, only as occasion demands, he refers to the accessory signs for confirmation. Should he, at any time, be in doubt about the depth of the narcosis, the first step is always to desist from giving more of the anesthetic until he has regained his bearings or the signs of awakening are recognized.

SOME IMPORTANT REFLEXES.

(1) Pharyngeal reflex. Coughing does not necessarily indicate awakening. It usually means that the vapor of the anesthetic is too concentrated and irritates the air passages. “Holding the breath” occurs even in fairly deep narcosis and has the same significance. The treatment is to dilute the anesthetic by admitting air.

(2) Ano-respiratory reflex. The crowing inspiration heard during operation on the perineum or rectum, does not indicate that the patient should have more anesthetic.

(3) The reflex produced by traction on the gall bladder or mesentery is similar in its significance to that of the ano-respiratory reflex.

VOMITING DURING ANESTHESIA.

It may happen to the conscientious anesthetist, who desists from giving more of the anesthetic until he has regained his bearings, that the patient suddenly shows signs of awakening, and vomiting begins. This is a disagreeable, but generally not a serious interruption. The anesthetist is absolute master of the situation. Although the patient’s face turns somewhat blue during the vomiting efforts, the anesthetist should not attempt to push the jaw forward or exert traction on the tongue. The face is merely turned to the side and kept in position by placing the hand on the cheek. The mouth and pharynx are cleansed gently with a piece of gauze and the anesthetic is continued, drop by drop. It is often surprising in such cases how rapidly the patient can be brought back into the proper plane of anesthesia. There need be no fear that the patient will fully awake.

OBSTRUCTED BREATHING.

Many anesthesias are unsatisfactory because the breathing is obstructed. To my mind the prime cause of obstructed breathing is too great a concentration of the anesthetic. The importance of avoiding the crowding of the anesthetic is the secret of a good narcosis.

The irritability of the air passages varies greatly in different individuals. Concentrated vapor may cause reflex spasm of the larynx and, consequently, obstructed breathing. This is the condition that leads to what is ordinarily called respiratory collapse. It is due to crowding—undue concentration—rather than excessive quantity of the anesthetic. If there were no superior laryngeal and trifacial nerves to warn the inexperienced or inattentive by closing the larynx to more of the anesthetic, real respiratory paralysis, which is apt to be fatal, and is due to direct toxic action of the anesthetic on the respiratory centre, might be more common.

“Have I crowded the anesthetic?” is the first question that should be considered when there are signs of obstructed breathing. The jaw is rigid, the patient is almost awake, and yet the mask is lifted to admit more air. Paradoxical as it may seem, the jaw begins to relax, the breathing becomes free and the anesthesia at once more profound. The reason is simple. As long as the spasm of the larynx persists the anesthetic cannot readily pass the barrier to exert its physiological action. As soon as the spasm is overcome by admitting air the anesthetic can be freely inhaled. By observing the precaution to dilute the anesthetic generously with air pharyngeal irritation and laryngeal spasm can be avoided and an undisturbed narcosis secured.

Sometimes, however, the obstruction is purely mechanical. It may be due to compression of the trachea by a shoulder brace. In aged individuals, after removing the tooth plate, progressively increasing cyanosis may be due to valve-action of the lips. Expiration is unhindered, but inspiration becomes impossible on account of collapse of the lips and cheeks. The difficulty is overcome by turning the head to one side and placing a spindle of gauze in the dependent angle of the mouth to keep the lips apart.

There are other cases in which the base of the tongue drops back into the oropharynx, and hinders breathing. There is a peculiar, noisy, “fluttering” respiration which indicates this condition. The jaw-grip, that is, pushing the jaw forward, is often insufficient. Most of us have been taught to use the wedge, mouth-gag and tongue forceps at once in such an emergency, but it is certainly desirable to escape this maneuver whenever possible. A naso-pharyngeal catheter, or breathing tube of soft rubber, passed through the nostril into the pharynx sometimes instantly relieves the obstruction.

THE USE OF THE BREATHING TUBE.

The breathing tube is a soft rubber tube 5/16” in calibre and 7¼” in length. The end is smooth and beveled and has an opening, there being a second opening on the side, about a quarter of an inch distant. To introduce it, the tip of the nose is lifted and the rounded end of the catheter directed into the larger nostril perpendicularly to the face. The use of a little white vaseline obviates friction and unnecessary traumatism. The tube is pushed gently back into the pharynx behind the receded base of the tongue until the respiratory air streams freely through it. Very rarely, it is necessary to pull the tongue forward until the tube is in position. At times it is of advantage to support the angle of the jaw lightly, in order to get the full benefit of the tube breathing. Oxygen, it is true, improves the color when the tongue has receded and there is partial asphyxia, but no one will argue that it eliminates the cause of the obstruction, viz., that the base of the tongue has dropped back into the pharynx and occludes the way to the air passages.

Sometimes, when the recession of the tongue is slight, supporting the angle of the jaw helps, because the base of the tongue is carried forward with it. Frequently, this is insufficient. The tongue may be drawn forward by means of forceps or suture, but this method is crude and necessitates also the use of a wedge and mouth gag. The same accessories are imperative, when an attempt is made to introduce a breathing tube through the mouth into the pharynx. It is for these reasons that the nasal route is preferred. The method outlined is uncomplicated—its efficacy is often striking. It seems to be the simplest solution of the problem to re-establish the respiratory air channel, which has been occluded by the recession of the tongue.

INDICATIONS FOR STIMULATION DURING NARCOSIS.