In a large number of clinic cases we have found that the daily maintenance dose is approximately two eat units which corresponds to three grains of the powdered leaf or thirty minims (sixty drops) of a good tincture. To produce saturation, therefore, we must give more than this maintenance dose at first. If the common 12 grain tables of a standard preparation are used, at least three a day will be required at first and it is often desirable to give four a day, two in the morning and two in the evening.
As you approach saturation the best guide is the heart rate and this must be determined in fibrillators by listening at the apex. When the rate begins to approach normal, 80 to 70, stop the digitalis for a day or two (stop it completely and do not simply reduce the dose) and the then give three grains a day. If the rate creeps up, it will indicate that the maintenance dosage in this particular patient is more than three grains a day.
If the rate falls below 60, it will indicate that the maintenance dosage is less than three grains a day. Thus you can experiment by giving one tablet one day and two the next or give two tablets as a dose five or six times a week. The slow method of digitalization which has just been outlined is usually the best.
The rapid method is more dramatic but is not often needed. In an urgent case with a very rapid ventricular rate, of 140 or more, with great discomfort a nd rapidly increasing passive congestion, the rapid method may be used. One simple form is to order a dram of tincture of digitalis every six hours until the apex rate is 90 or less. One, two or at most three doses will accomplish this result. Another method assumes that ten can units or ten tablets of 12 grains each will saturate or nearly saturate your patient.
Space the doses six hours apart, counting the heart rate at the apex before each dose and give five tablets for the first dose, three for the second and two thereafter every six hours until the heart rate has been reduced to 90. Then stop the drug and you will find in twelve hours that the rate will probably be 70 or less. In this way patients can be digitalized within eighteen or twenty-four hours very safely. After waiting another day the maintenance dosage will have to be started, beginning with three grains a day until the exact individual requirement can be determined by trial and error.
In using the rapid method it is simpler to follow a general rule rather than to attempt any calculation based upon the patient s weight. Such calculations give a false sense of security because the individual differences in susceptibility of patients will always; defy calculation. In all these methods we follow the counsel of Withering. Withering, Wm.: “An Account of the Foxglove and Some of Its Medicinal Uses: with Practical Remarks on Dropsy and Other Diseases,” Birmingham, M. Swinney, 1785. to give the drug until we get the effect desired, pushing it consistently until we get that effect.
The common errors in digitalis dosage have already been mentioned. Insufficient dosage without ever securing an adequate effect is the first. The second mistake is to continue large doses which are necessary for saturation but which produce toxic symptoms if they are continued beyond the point of useful saturation of the heart muscle.
We know that many cases of heart disease will secure benefit from moderate or even small doses of digitalis without even approaching complete myocardial saturation but these cases are not the ones that you encounter in bed will swollen legs, large liver or moist Rales at the lung bases.
When digitalis has done all that it can without bringing about the relief we have hoped for, we must go a step further by the use of diuretics. It is not logical to attempt a direct attack before digitalis has brought the circulation up to its optimum efficiency as the kidneys cannot get rid of fluid that is not brought to them. On the other hand the peripheral edema as well as the stasis in the kidney seems to acts as a peripheral block so that digitalis may not be able to exert all its effects without the assistance of diuretics. Digitalis has no direct diuretic action upon the kidney in therapeutic doses.
It produces an increase in the output of urine by its action on the circulation, by bringing more fluid to the kidneys. In this sense it is an indirect diuretic but cannot properly be called a diuretic drug. It is wise to give digitalis for two or three days at least before considered diuretic medication, and, if improvement is evident, the use of diuretics may be postponed.
The most effective diuretic which can be given by mouth is theocin. It may be ordered in capsules containing four or five grains to be taken three time a day immediately after food. Irritation of the stomach is an occasional effect of theocin and therefore it is important to give it after meals. It should not be continued for more than three to five days at a time so as to avoid renal irritation and it is wise to watch the urine for showers of red cells during treatment. If a course of theocin lasting four or five days has not had any effect, stop the drug and avoid diuretic measures for at least forty-hours, so as to give the kidneys a rest.
If theocin by mouth is not effective, we must turn to one of the diuretics used intravenously or intramuscularly: Salyrgan or Mercupurin. These may be given by deep intramuscular injection, but an eschar is always a possibility. If the veins are readily accessible, intravenous use is to be preferred. A dose of 2 cc. should be given first, followed in twenty-four or forty-eight hours by 1 cc. A dose of 1 or 2 cc. may then be given every second or third day. If is possible to keep chronic cases in comfort by a weekly injection over long periods. I have had several patients with irreducible congestive failure who have had their edema kept within comfortable limits by this medication.
The effect of these strong diuretics will be enhanced by preparatory treatment: ammonium nitrate or ammonium chloride in doses of at least fifteen grains three times a day for a few days before the intravenous injection. Enteric coated tablets containing 72 grains of either of these salts are available and the patients should receive two or more tablets per dose. If well tolerated he may take three or four tablets three times a day over long periods.
When the diuretic effect has been secured i t can often be maintained by the use of urea in 50 per cent solution, one to two ounces or more per day. For psychologic reasons the nature of the drug should not be revealed to the patient. The taste can best be disguised in sarsaparilla, in my experience, although orange juice and beer can be used as vehicles. I have observed that patients maybe disturbed at night by the need to urinate when area is given in the afternoon or evening. As a rule, therefore, I divide the daily ration of urea, which may be as much as four or six ounces of the 50 per cent solution, into two doses, one to be taken with breakfast and the second after lunch.
The daily use of urea may be necessary in some cases in order to control edema.
The term irreducible congestive heart failure which I have just used is a confession that all these methods of treatment (rest, limitation of fluids and salt, digitalis and diuretics) may be ineffective. Even than the outlook is not necessarily hopeless as we have another method in reserve. Blumgart and his associates in Boston deserve credit for the pioneer work on this problem. They have attempted to control congestive heart failure by reducing the basal metabolic rate. To accomplish this, total thyroidectomy has been successful in a large series of cases. Bulgmart, H.L., Riseman, J.E.F., Davis, D., and Berlin,.
A low basal metabolic rate from our present point of view means practically that the tissues are content with an amount of oxygen which is less than they would demand if the metabolic rate were higher. The speed of the blood flow determines the rate of oxygen supply tot he tissues. If the rate is low the tissues may be satisfied by the reduced amount of oxygen furnished by an impaired circulation. Thus removal of the thyroid gland by reducing the metabolic rate will bring the demands of the tissues within the capacity of the circulation when it is impossible to raise the efficiency of the circulation beyond a certain subnormal limit.
This is a new and novel attack on the problem of heart failure and has proven to be effective in a fair percentage of cases. In two cases which I have observed the patients were bed-ridden, one for nine months, the other for over a year. After total thyroidectomy they are both up now, able to carry on moderate activities without excessive dyspnea or other distress. The fear of undesirable effects following the operation is apparently unfounded. These patients do not become mentally sluggish if the basal metabolic rate is kept at about minus 25 per cent. A small daily dose of thyroid suffices for this.
