BRITISII JOURNAL OF PLASTIC SURGERY VOL. V JANUARY 1953 NO. 4 EDITORIAL HYPOTENSIVE DRUGS IN ANE~STHESIA THE introduction into ana:sthesia of a controlled hypotension has brought to the patient many direct and indirect advantages which for the most part cannot be obtained otherwise. Thus surgical ha:morrhage can be so reduced that ha:morrhagic shock is no longer feared in operations where previously bleeding was so intense as to necessitate multiple transfusions. Indeed, on rare occasions a controlled hypotension affects not only the success of the operation but the chance of survival of the patient. Such dramatic effects, however, are seen only very occasionally, and in the vast majority of patients a controlled hypotension maintains a clarity of vision in difficult inaccessible regions which thereby assists the surgical technique so that the operation is quicker, more skilfully performed, and thus more satisfactory. In plastic surgery bleeding is often profuse from such highly vascular tissue as skin and mucous membrane, whilst the radical removal of malignant growths and their immediate repair often entail a very considerable blood loss. Ha:matoma formation inside and beneath skin flaps and grafts can endanger the success of the entire operation, and may occasionally be responsible for a more extensive loss of tissue so laboriously obtained by previous operations. Reactionary ha:morrhage, however, is unlikely after carefid control of blood- pressure both in the theatre and during the immediate post-operative recovery period. With effective h~cmostasis, skin grafting is more successful. Skin flaps and pedicles do not become congested and cyanosed when the arterial pressure is low, but an adequate blood supply can still be maintained through the dilated arterial channels. Further advantages include a reduction in tissue-bruising and in ~edema, particularly noticeable in operations on the face and neck and in certain ophthalmic operations. For this reason post-operative comfort is increased and healing occurs quickly. Complications have arisen from the use of hypotension in anazsthesia. It is at present difficult to assess the extent or nature of these troubles for few have been reported. From the little ,widence at present available it is impossible to draw valid conclusions. Hewer and Goldsmith report the occurrence of unilateral amaurosis with r~" "q recovery after using hexamethonium iodide during the operation of rad :astectomy (Brit. reed. J., 1952, 2, 759). They conclude that spasm of the cent~a: retinal artery.was the most likely cause of this complication in their patient. Other complications are said to include hemiplegia, paraplegia, and total blindne~ -'om retinal atrophy, but no evidence is given in support of these claims (,4 :'sthesla, I952, 7, 65)" Coronary and cerebral thromboses occur 4 A 22I 222 BRIT ISH JOURNAL OF PLASTIC: SURGERY after " normal" anmsthetics, i.e., an uncontrolled blood-pressure. They have occurred also after an induced hypotension. Blood flow in vital organs does not depend entirely on blood-pressure. The state of constriction or dilatation of vessels is of greater importance. It is at present impossible to assess the significance of coronary and cerebral thrombosis in association with low-pressure anazsthesia until a greater knowledge has been obtained of the factors affecting circulation in these vital organs. Cardiac arrest occurred once with hexamethonium in a series of I,OOo hypotensive anmsthetics, whilst during the same period it occurred twice in 5,2c'o other " normal" ana:sthetics, all administered by the staff of one hospital. Cardiac arrest is considered a likely complication of an induced hypotension, especially when the initial fall of pressure is very sudden and severe. Under such conditions the heart can be starved of blood and will stop. The careful induction of the optimal hypotension and its exact maintenance are vital safety factors. Errors of technique and judgment in the administration of the ana:sthetic and in the use of hypotensive drugs have undoubtedly been responsible for many of the complications. A systolic pressure between 55 and 85 mm. Hg has been induced and maintained for varying lengths of time in a very large number of patients. From personal communications and published figures this number can be stated to be in excess of 3,ooo. This is striking support for Gillies' statement that a hypotension of 60 mm. Hg is adequate to support cellular respiration and metabolism in all the vital organs, provided the blood is well oxygenated and provided vasodilatation is ensured. Naturally, the ill-effects which have been encountered have made surgeons and ana:sthetists very hesitant about employing hypotension. The desire for clear-cut indications and for justification can be understood. But it must be remembered that the reduction of a severe and dangerous blood loss to an insignificant amount is encountered only rarely. Hypotension is essentially a refinement which allows the achievement of better surgery. There are very few operations where it is indispensable. It is therefore vitally important to ensure safety for this type of work. Safety depends on the skill of the ana:sthetist and the co-operation and competence of the surgeon. The present position can be compared with the early days of general ana:sthesia when safety was not of a degree high enough to warrant its use in relatively minor procedures on the face and neck which were then performed under local, but which are now almost always performed under general anazsthesia, with added benefits to both patient and surgeon. Further work and experience with hypotension will in like manner ensure greater safety. A controlled hypotension is unnecessary and unjustified for every patient. For the present the necessary skill and competence are not available in every anmsthetist. Hypotensive anazsthesia demands constant care and attention as well as considerable practice in order to achieve safely improved Operative conditions and results. The benefits of hypotension have enabled a dramatic forward step in certain fields of surgery. It is now possible to perform two, three, and occasionally more stages as one in some multi-stage operations. This is especially valuable in the repair of secondary hare-lip and cleft palate and in extensive skin grafts of the face. These combined surgical operations can be successfully completed with an ease and skill which would have been impossible in the presence of normal anazsthetic ha:morrhage. This is a real advance in modern surgery. EDITORIAL 223 I f it is the considered opinion of the surgeon that any particular operation can be performed equally well and with as great a chance of success without hypotension, then it should never be used. The benefits of hypotension are welcomed by surgeons who are constantly striving to perfect their technique and results. For this reason surgical skill should match the improved facilities which this technique provides. It is therefore inadvisable to employ it freely for trainee and junior surgeons who are trying to master the technique of the operation, for their skill is not yet sufficient to make use of all the advantages which hypotension offers. At the same time it must be remembered even by those who are most skilled and enthusiastic that this work is difficult and exceedingly trying for the anmsthetist. Future developments in the measurement of blood-pressure and in the technique of control may reduce this burden and make the work less arduous. They will also enable hypotension to be applied to a wider selection of patients, and more especially to those in the younger age groups who are now so difficult." This work will enlarge and enrich our knowledge of the heart's action and of the dynamics of the circulation. G. E. H. E.