38 SPECULUM
SPECULUM 39 (1) Ascertain the patient's name and call him by it.
(2) Speak reassuringly, and explain, when necessary, what you are doing, i.e., when covering the eyes with face piece, tell him it is to keep the vapor out of the eyes.
(3) Have everything ready beforehand; don't put the face piece on and leave him blindfolded, in suspense, while you fill the ether bottles. Incident- ally, the mask should be covered with eight to 12 single layers of gauze; if there are too few layers, evaporation is hindered, and if too many, an excessive amount of CO2 is collected beneath it.
(4) Always inquire about dentures; they should be, and usually are, removed; but occasionally they are forgotten. Ultimately the anaesthetist is responsible.
(5) Look in the mouth for loose teeth, fillings, etc.
(6) Remember, hearing becomes acute and is the last of the special senses to go; therefore do not carry on a conversation with a third person or allow others to talk—the patient expects your whole attention.
(7) You are trying to coax a patient to sleep; it is doubtful if asking him to count helps, and, incidentally, some people object.
(8) For the same reason do not ask questions; if you wish, you can assure him that he is doing well.
(9) Do not tell him to take deep breaths, or when voluntary control goes, the breathing will become shallow or stop.
The induction period, i.e., from the commencement of Stage I to 1st Plane Stage III is the most important and most difficult from the anaethe-
tist's point of view; important because a smooth 1st and 2nd stage means usually a smooth 3rd stage; difficult because he has to coax a patient to breathe an increasing concentration of an irritating vapour. Clinically, a patient is anaethetised when the tension of ether vapour in the blood reaches 40 to 50 mm.Hg., corresponding to 6-7% ether in inspired air. The attain- ment of that tension in a reasonable time, however, requires an initial tension of about 140mm. or approximately 18% in inspired air, because at first the vapour in the blood stream diffuses to the tissues and not until the tissues become relatively saturated can the tension in the blood rise and equilibrium be reached. Hence a progressive increase is necessary during Stages I and H.
If this is interfered with, anaesthetisation is delayed and becomes lighter.
However, the most universal fault of the beginner to hurry the induction;
this not only defeats its own object, but is the cause of most of the difficulties that arise at this stage.
Ethyl chloride is nearly as potent a drug as chloroform and therefore should be given with plenty of air. If dropped on an open mask it evapor- ates in the gauze and is inspired diluted with air; if sprayed on, some of the vapour may go through the gauze and reach the patient in high concentration.
As soon as breathing becomes deeper than normal and regular, switch to ether and drop the latter on as fast as the patient will breath it. (It is better to drop the ether on the mask throughout the administration and to increase or decrease the rate of dropping, rather than to pour it on intermittently).
If he "gags" or holds his breath, stop the ether, since there is obviously no point in putting ether on a mask if the patient is not breathing.
SPECULUM
Use your eyes—watch the colour (always have an ear uncovered by towels) and if it is pink don't remove the mask, presumably (as someone once remarked) to see if the patient is still underneath. As tolerance to ether vapour increases, and because there is a limit to the concentration obtainable on the open mask, you will need to fold a towel over the mask, draping it well down over the edge to prevent the heavy ether vapour escaping; this not only increases the concentration, but also increases the depth of the respirations.
There is then only one reason for the level of anaesthesia not increasing
—the vapour is not reaching the alveoli of the lungs. Some of the common causes are:—
(1) Mask may have slipped away from escaping between mask and face.
(2) Shallow breathing—often due to premedication.
the face, or too much vapour is drugs, etc. Morphia or heavy (3) Obstruction at lips in edentulous patients resulting in a valve-like action; the more you push up the chin, the greater the obstruction.
(4) Clenching of teeth due to spasm—if the patient has no nasal obstruction, the level of anaesthesia will increase and the spasm be relieved;
but if the colour does not remain pink, give air or oxygen.
(5) Dropping back of tongue: Relieve by pushing the mandible for- ward.
(6) The presence of mucus: Avoid by giving atropine beforehand. Do not force the ether—turn the head to one side and mucus will collect in the cheek, where it may be removed with "sucker." Do not turn the head upright or over to the other side with a pool of mucus still there or it may run into the trachea.
( 7) Laryngeal spasm due to (a) high concentration of ether, (b) mucus between the cords, (c) badly fitting airway, (d) unknown causes: It is said to be more common when morphia is used as preliminary sedative. It is difficult to abolish—try carbogen or oxygen. It often disappears as anaesthe- sia deepens. When occurring during Stage III, it is usually due to reflex from
the site of operation; do not try to abolish it by deepening the anaesthesia unless you are certain the patient is not already deeply anaesthetised.
There are other causes, but the above are most frequently encountered.
The introduction of an airway as soon as the patient will tolerate one often facilitates matters.
Having brought the patient to the stage of surgical anaesthesia (Stage III), the anaesthetist must give him unremitting attention, particularly as regards the colour and respiration. The tendency is for the beginner to overdose with ether. The level of the anaesthesia should be varied with the needs of the surgeon. It should be realised that certain tissues (e.g., skin and peritoneum) are much more sensitive than others and a lower level of anaesthesia maintained when less sensitive tissues are being handled (e.g., actual cutting and suturing of bowel).
If the patient has been "saturated" before the surgeon begins it will be found quite easy to vary the depth, but keep a little ahead of the surgeon.
Should rigidity develop, do not give more ether until you are quite sure that it is not more oxygen that is needed. Relaxation and an obstructed airway
SPECULUM 41 do not co-exist. Noisy breathing is always obstructed breathing, although the converse is not always true, e.g., a patient with a depressed respiration centre and resultant shallow breathing may show lack of oxygen only by increasing cyanosis.
The most reliable and constant eye signs are the lateral oscillation of the eyes, or the eccentric fixation in late Stage II.
In Plane I of Stage III the oscillations persist but become more sluggish until finally central fixation occurs indicating the, entry into Plane II.
In conclusion:
(1) Do not hurry the induction.
(2) Maintain a patient's airway—correct the slightest obstruction as soon as you detect it. Avoidance of anoxia is a primary consideration.
(3) Listen to the breathing and watch the colour from the commence- ment of the anaesthetic.