Intravenous Anæsthesia with Special Reference to the Use of the Barbiturates

INTRAVENOUS ANAESTHESIA WITH SPECIAL REFERENCE TO THE USE OF THE BARBITURATES By K. W. LEON CAPTAIN, R.A.M.C. General consideration The first successful intravenous anaesthesia, produced in man was accomplished by Ore of Lyons in 1872 : for this purpose he used chloral hydrate. Since that date a variety of drugs has been used for the same reason including the follow- ing :?diethyl ether, hedonal, ethyl alcohol, tribromethyl alcohol or avertin, and the rapidly- acting barbiturates. I propose in this article to deal with the use of the last group but feel that a word or two on the subject of the barbiturates as a whole would not be out of place. They fall into three main groups :? 1. Long-acting.?e.g. allonal, dial, luminal, medinal, trional, and veronal. 2. Short-acting.?e.g. sodium amytal, nembu- tal, pernocton, rectidon, and Seconal. 3. Rapidly-acting.?e.g. evipan sodium, pentothal sodium, sodium thoethamyl, eunarcon, and narconumal. Those in the first group are administered mainly by the oral route, and are used as sedatives or hypnotics, though luminal may be used as a basal narcotic. Those in the second group may be given by the oral or intravenous 660 THE INDIAN MEDICAL GAZETTE [Nov., 1942 routes, and are mainly used for the production This figure refers to pentothal sodium, which of basal narcosis. Those in the third group, is the drug most extensively used in this work. sodium and especially evipan pentothal sodium, Continuous pentothal anaesthesia has been used are almost invariably administered by the in London by intravenous method for the of extensively recently, notably production with Carnac Rivett at the anaesthesia of duration. Quayle working proper varying Chelsea Hospital for Women. Every gynaeco- All the barbiturates have a common chemical logical operation, including complete Wertheim grouping clearances, has been undertaken successfully. NH CO I myself have employed it for herniorrhaphies appendicectomies, gun-shot wounds of abdomen c< some NH COK and other parts and in severely shocked patients. and to this common sodium grouping sulphur In such cases, provided the technique de- or other molecules be attached. There is may scribed below is adhered to, it has given satis- thus obtainable a of very large variety drugs. factory if not striking results. Other therapeutic uses to which these drugs may be put are as sedatives and anti-convulsants in Technique of administration and effects of the treatment of chorea and delirium tremens. barbiturate anaesthesia They are also used for the control of late ether Before discussing the actual and convulsions arising during anaesthesia, and finally dosage methods employed in this form of anaesthesia, they have in recent years been used extensively ' I would like to point out that in my opinion some in psychiatry, a process known as narco- premedication should invariably be given, and analysis that each should be treated In the effect of these is variable patient individually. general drugs I think it is true that there is no standard ?so many factors are involved. In a thous- amount of any given drug that will suit every and cases, it was found that the most resistant case. There are all kinds of factors individual four times the dose of the involved, required or least resistant. e.g. weight, general condition, presence absence of and the reaction of the The barbiturates, however administered, shock, etc., patient to any given dose of barbiturate (or cause some lowering of blood pressure and some any other For these reasons are excreted anaesthetic). every respiratory depression. They by case should be assessed on its merits. As a the liver as urea, though the blood-sugar and general rule I give omnopon gr. 1/3; scopola- blood-urea values are little affected during mine gr. 1/150 but this can be increased or re- anaesthesia. In gross agranu- overdosage a combination. or toxic occur. All the placed by morphine-atropine locytosis jaundice may this I the barbiturates offer some the (In country replace atropine by protection against In the toxic effects of cocaine and chloroform. hyoscine hydrobromide gr. 1/100.) selection of a vein, any vein can be used with Indications and contra-indications the exception of the varicose variety: in these The indications for this type of anaesthesia stagnation and thrombosis may occur, which are quoted in most textbooks are? obviously to be avoided. 1. Short anaesthesia if N20/02 is difficult to The common difficulties occurring in intra- obtain, especially for operations upon the mouth venous work are transfixation of the vein and and face. excessive mobility of the vein, and the best 2. Anaesthesia where the diathermic cautery methods of overcoming these are to use a short is to be employed. bevelled needle and to use the angle of two veins 3. Anaesthesia where chronic respiratory if possible for injections, viz, disease is present. 4. Ophthalmic operations. The contra-indications usually given are as follows :? 1. Gross impairment of liver or kidnev func- There are three methods of administration, tion. the single dose method, the repeated method, and 2. Severe cardiac or respiratory embarrass- the continuous method. In the first method, ment. sufficient evipan sodium or pentothal sodium is 3. cervical Deep sepsis (e.g. quinsy). injected, with or without a safety pause, till con- Asthma. 4. sciousness is lost?:a further few c.cm. are put in I would like to a put forward plea for the use and a total of | to 1 g. used in all. This should of barbiturate anaesthesia in a much wider field give an anesthesia lasting some 5 to 6 minutes than that indicated above,- and I feel that this and ample time for small surgical procedures to type of anaesthesia has a definite place in the be performed. treatment of In surgical injuries to-day. my In the second method, at least 20 c.cm. of it is safe to this method in opinion employ solution are 1 to 1.5 g. of barbitu- of and employed, operations any length severity, provided rate being injected in small quantities, the that a total of 3.5 is not dosage g. exceeded; needle being kept in the vein throughout. By Nov., 1942] LUNG TUBERCULOSIS: EISENSTAEDT & RINDANI 661 this means a longer anaesthesia of some 10 to 15 minutes is obtained. In both of these methods, a 5 per cent or 10 per cent solution is employed. In the third method a preliminary ? gr. of barbiturate is injected till consciousness is lost. 1 to 2 g. further are now dissolved on 560 c.cm. of either glucosaline plasma or whole blood. This mixture, which results either in a 1/6 per cent or 1/12 per cent solution, is now given by any simple drip apparatus. I myself use a drip designed by Professor Macintosh of Oxford which was fully described in a recent issue of the Lancet, and have succeeded in producing adequate anaesthesia for most surgical operations which will last if necessary up to a period of two hours. As mentioned above, no more than a total of 3.5 g. of barbiturate should on anv account be given. Induction with these drugs is rapid and pleasant, the patient gradually feeling sleepy, yawning a little and gently passing into uncon- sciousness. There is occasional twitching with but with pentothal sodium a very evipan sodium, ' smooth ' fade out is assured. The blood The pressure falls and respiration is depressed. tongue falls back and an airway is essential. The depth of anaesthesia should be judged by the depth of respiration and by the relaxation of the masseter muscles. The eye signs are unreliable and in my opinion can be ignored. is and various Recovery prolonged, sequelae (Continued from -previous column) have been described, such as excitement, drowsi- bottles of or are headache, nystagmus and glucosaline plasma necessary. ness, photophobia, This is an advantage over the carriage of heavy- bradycardia. cylinders of and the accompany- cases in which I have adminis- N20/02, etc., In the many ing machines: more particularly is it so in this tered sodium, I have never seen any pentothal country, where for the moment there appears of these drowsiness, and on the rarest except only to be a shortage of the latter articles. has there been of occasions any post-operative I would like to say that I have been is indicated intense Thirdly, vomiting. Overdosage by much impressed with the results of continuous and circulatory If this respiratory depression. barbiturate anaesthesia in patients who were treated or occurs it may be by C02/02 mixtures, suffering from some degree of shock. intravenous of coramine (5 to 10 the injection Obviously no patient should be operated or (3 mgm.). lumbar c.cm.) picrotoxin Repeated upon until resuscitation has taken place. There is also said to assist. puncture are, occasions in which operations are or two further I would however, There are one points urgently required at the earliest moment consis- as in favour of this like to make arguments type tent with the patient's safety. of anaesthesia. In cases of this type, in which I have used Firstly, I think it can be said that by using this method, the results have been good. Blood trauma is reduced to the barbiturates, psychic pressure readings have at the most showed a to me the a minimum. It seems that whatever drop of 10 mm. Hg. during the operation. There method subsequent anaesthetic, induction by this have been practically no post-operative com- results. gives rise to the best plications, and very rarely any vomiting or All patients with whom I have discussed the headache; the long 'carry over' produced has question, both in civil and military work, agree also benefited such case, in that it produces a have to that it is a pleasant method.

Load more