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Simplified Method of Curare Administration in Cataract Surgery*
S I M P L I F I E D M E T H O D O F CURARE ADMINISTRATION IN CATARACT SURGERY* OSCAR DAHLENE,
M.D.
Hattiesburg, Mississippi AND J. WESLEY M C K I N N E Y ,
M.D.
Memphis, Tennessee
The use of curare in cataract surgery has not been universally accepted, possibly be cause of the fear of complications or the necessity for the assistance of an anesthetist for its administration. It is the purpose of this communication to present a simplified technique of curare administration which has eliminated the need for an anesthetist and has been without the slightest untoward re action in ISO cases of cataract extraction. The advantage of a quiet eye in a relaxed patient during cataract surgery needs no exposition. Curare is a valuable aid in se curing this. The drug has for the ophthal mologist the happy property of paralyzing the muscles about the eye in lower dosages than are required for paralysis of the other skeletal muscles. It has been found that increasing doses injected intravenously produce first paralysis of the eye and facial muscles and then in order, those of the pharynx, larynx, and ex tremities. As the dose is increased, the inter costal muscles and lastly the diaphragm are paralyzed. The paralysis of the ocular muscles occurs not only at a lower dosage but last longer than the paralysis of the other skeletal muscles. The effect on the ocular muscles of a single intravenous in jection of curare reaches its maximum in about four minutes, continues for 20 to 25 minutes, and then falls off rapidly. Kirby 1 and Clark 2 were the first to make use of this selective effect in ophthalmic surgery. Others have confirmed their ob* From the Department of Ophthalmology, Uni versity of Tennessee College of Medicine, John Gaston Hospital, and Memphis Eye, Ear, Nose, and Throat Hospital, Memphis, Tennessee.
servations. Cordes and Mullen3 and Hender son4 have reviewed the literature, giving a thorough coverage of the history of the dis covery of curare and its evolution from a medical curiosity to a useful aid to ocular akinesia. MODE OF ACTION OF CURARE
The pharmacodynamics of curare have been extensively treated in previous publica tions.1· 3 ' 5 We may summarize by noting that curare acts by way of the blood stream to eliminate the response of individual striated muscle fibers to the acetylcholine liberated at the myoneural junction. Very large doses block the response of smooth muscle fibers also. It is interesting to compare this action with that of procaine. The latter has the property of blocking the production of acetylcholine at the myoneural junction. The paralysis produced by procaine may not be complete because of insufficient saturation of the nerve or because excessive nerve im pulses from above may get through to the myoneural junction in the very apprehensive patient. That the production of acetylcholine is not always completely suppressed by procaine injections is often observed clinically. Ap parently effective O'Brien or Van Lint akinesia may not prevent squeezing of the lids from fright or painful stimulus. Retrobulbar injections of procaine regularly do not produce complete paralysis of the extraocular muscles even when reinforced by epinephrine and hyaluronidase. The paralysis produced by curare is not affected by the greater production of acetyl choline from efferent motor impulses be-
697
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OSCAR DAHLENE AND J. WESLEY McKINNEY
cause the muscle fibers are rendered incapa ble of contracting; however, much acetylcholine is produced at the myoneural junc^ tion. Thus, there is greater security in the paralysis produced by curare than in that produced by procaine. Kirby,ç Barraquer, 7 Henderson, 4 and others have depended entirely on curare for securing paralysis of the extraocular muscles. On the other hand, Cordes and Mullen3 have merely added curare to their routine Van Lint akinesia and retrobulbar procaine injec tion. To combine the action of curare and pro caine seems logical, if, in fact, the two drugs act synergistically. No experimental evidence for this synergism could be found, but clini cally it is readily demonstrable.
however, that, on occasion, patients in whom four cc. or more were required com plained of a mild sense of suffocation, which caused a little apprehension on the part of the patient and surgeon. The symptom al ways passed off quickly, however, and the patient was easily relieved by oxygen blown over the mouth under the drapes. This inconvenience led us to resume the use of the retrobulbar injection of procaine epinephrine and hyaluronidase followed by injection of curare, one cc. at a time until the desired effect was obtained. It was soon apparent that only two to three cc. of curare were required rather than the usual three to four cc. when curare was depended upon alone. Before beginning the injections of curare, the effect of the retrobulbar procaine was CLINICAL OBSERVATIONS assessed. The patient's ability to rotate the We were led to undertake the use of eye on command was extremely variable. In curare in cataract surgery by the evident ad dividual responses varied from almost com vantages of its use as set forth by Kirby.6 plete inability to rotate the eye in some cases Initially no retrobulbar injection was used. to a response with wide excursions of the Curare was injected by intravenous drip eye. in others. Curare was then given, one under the control of an anesthetist. One cc. cc. at a time. Although the dosage required was injected at a time at four-minute inter was less, paralysis was the same as with vals until the desired effect was obtained. It curare alone. In making our observations we soon ig was found that the average dose of curare necessary for the effective paralysis of the nored the orbicularis muscle, in view of the extraocular muscles ranged between three to fact that the effect of curare on this muscle four cc. of d-tubocurarine (3.0 mg. per cc. closely parallels its effect on the extraocular or 20 units per cc.) Occasionally five cc. and muscles. It is also more convenient to have rarely even more than five cc. were required. the speculum in place while observing the Preoperative medication consisted of 75 ocular rotations. Furthermore, the tonus of mg. of Demerol and 1/150 gr. of atropine the extraocular muscles is a much more im portant factor than contraction of the orbi given subcutaneously. From time to time during the curarization cularis in producing the expulsive force re and before the beginning of the operation, sponsible for complications during the time the patient was asked to look upward, down that the eye is opened. Since the reduced dosage of curare (two ward, and horizontally. Upward movements were first abolished, then downward, and to three c c ) , given one cc. at a time after finally horizontal rotations. It was not con procaine injections, had proved effective it sidered necessary to abolish completely all was decided to try two cc, given at a single horizontal rotation or the slight rotatory injection. This dose is one-half that which had been noted to cause a sense of suffoca movement which usually remained. No serious complication was encoun tion in certain of those cases wherein curare tered using this technique. It was noted, was used without retrobulbar procaine. The
CURARE ADMINISTRATION extraocular muscle paralysis produced by this rapid injection of low dosage proved to be equal to that produced by curare alone or retrobulbar procaine and curare administered more slowly. Two parallel series of cases were then set up. In each series, two cc. of curare were injected at one time and no more. A total of 82 cataract extractions were performed using a rapid intravenous drip of curare in fivepercent glucose solution. After all the curare had entered the vein, the drip was continued at a reduced rate throughout the operation, while the anesthetist sat by the patient. In the other series, 68 cataract extractions were performed wherein the curare Was given as a single intravenous injection by the circulat ing nurse. Both methods were equally effec tive. The antidote Tensilon (N-ethyl'M-hydroxyphenyl'-N, N diethylammonium bro mide) and oxygen were kept in readiness but never used. No untoward symptoms were noted in the ISO cases observed. PRESENT TECHNIQUE
Curare has been considered by us to be merely an addition to the medications used for control of the eye and the patient to be operated upon. Premedication consists of three gr. of sodium amytal, SO to 100 mg. of Demerol, and 1/150 gr. of atropine. Oc casionally, in the case of a large, tense patient, an additional 50 mg. of Demerol is given intravenously along with the curare. The installation of cocaine (four percent) is begun in the patient's room and continued in the operating room. Routine O'Brien akinesia and retrobulbar injection of procaine, epinephrine, and hyaluronidase are per formed. The operation is begun immediately upon the completion of the retrobulbar injection. The conjunctival flap is dissected, and troublesome bleeding points cauterized. The superior rectus bridal suture is inserted and secured so as to rotate the eye to the position desired. When everything is ready for the
699
incision into the anterior chamber, two cc. of curare are injected rapidly into the vein of the arm. Observations of the ocular rotations are no longer made. Since the effect of curare reaches its maximum within four minutes and lasts 20 to 25 minutes, the eye and the patient arrive at the maximum relaxation at about the time the sutures have been placed and the iridotomy completed. The surgeon, therefore, need not hurry because he can be sure of adequate time even if complications should arise. COMMENTS
The oustanding advantages of curare ad ministration are -the immobility of the eye and the absence of expulsive force which it assures. It is entirely feasible, after the lens has been removed, to lift up the corneal flap and inspect the vitreous directly. The vitre ous face may be found to be only slightly convex or even concave, indicating the ab sence of vitreous pressure. In no case have we seen vitreous well up and burst after the lens is removed, even in the very bad actors on our charity service. Remnants of a torn capsule may be grasped and removed under direct vision. Collateral benefits of curare are a relaxed surgeon and an almost unconcerned patient. The intelligent patient who comes to the operating room awake despite the premedica tion and afraid that he might make a move during a crucial stage of the operation, loses his apprehension, relaxes, and may even go to sleep after the curare is injected. The complete absence of untoward side reactions to the injection of two cc. of curare was gratifying. Patients operated upon ranged in age from 31 to 86 years. The usual degenerative conditions of the elderly were encountered. Two moderately severe asthmatics had no difficulty. Preoperative medication with 1/150 gr. of atropine pre vented bronchospasm and excessive secre tions. No cases of myasthenia gravis were seen.
700
W. LEYDHECKER
Vitreous was lost in seven cases (4.7 per cent) of 150 cases operated upon. In none of these was forward movement of the vitre ous body accountable for the loss. Rather, the loss was attributable to factors such as undue adhesion of vitreous face to lens (both eyes of same patient), surgical accidents, or temporary ineptitude of the surgeon. CONCLUSIONS
Our observations on the use of curare in 150 cataract extractions confirm the opinion of others that it is a valuable adjunct for the better control of the patient who is to undergo cataract surgery.
A reduced dosage of curare (two cc.) act ing synergistically with the procaine of the retrobulbar injection and O'Brien akinesia yielded effective relaxation of the extraocular muscles and eyelids. Preoperative sedatives plus curare yielded a completely relaxed pa tient. No untoward symptom was noted with the small dosage used (one-half the dose previously noted to cause a complaint of mild suffocation). The services of an anesthetist are no longer considered necessary. Hall Street. 921 Exchange Building (3).
REFERENCES
1. Kirby, D. B.: Use of curare in cataract surgery. Tr. Sect. Ophth. A.M.A., 1949, pp. 279-293. 2. Clark, W. B. : Use of curare as an adjuvant in cataract surgery. Watson Gaily Eye Foundation Quart., 1:34, 1949. 3. Cordes, F. G, and Mullen, R. S. : The use of curare in cataract surgery. Am. J. Ophth., 34 :SS7-S64 (Apr.) 1951. 4. Henderson, J. W. : Curare akinesia in cataract operations. Am. J. Ophth., 36 :781-788 (June) 1953. 5. Drucker, A. P., Sadove, M. S., and Unna, K. R. : Ophthalmic studies of curare and curarelike drugs in man. Am. J. Ophth., 34:543-553 (Apr.) 1951. 6. Kirby, D. B. : Curare in cataract surgery : Five years' experience. Tr. Sect. Ophth. A.M.A., 1952. 7. Barraquer Moner, J. I. : The present technic and results of the use of curare in ocular surgery. Am. J. Ophth., 36:789-794 (June) 1953.
INFLUENCE OF COFFEE UPON OCULAR TENSION* I N NORMAL A N D I N GLAUCOMATOUS EYES W.
LEYDHECKER,
M.D.
Bonn, Germany
We have been taught that glaucoma pa tients should not drink coffee because this would increase the ocular tension. In coffee drinking two factors could influence the tension, caffeine and water. The effect of water drinking upon the ocular tension has been the subject of many publications1"21 and was studied in detail in my own com munications.22-27 Caffeine has been applied as a provocative test,28-36 but the limits between physiologic and pathologic reactions of the tension have not been clear so that ♦From the University Eye Clinic, Director: Prof. H. K. Müller.
evaluation of the test was difficult. I have applied both the caffeine and the water-drinking tests to a number of persons with normal and glaucomatous eyes in order to prove their reliability and to study the hygienics of glaucoma. EFFECTS OF CAFFEINE ON NORMAL EYES
In 198 eyes of 109 healthy subjects a pro vocative test with caffeine was performed. Five tests were done with 45 gm. of coffee in 150 cc. water, 11 tests with 0.5 gm. caf feine sodiobenzoate intravenously, and 182 tests with 0.4 gm. pure caffeine plus 150 cc. water.
M.D.
Hattiesburg, Mississippi AND J. WESLEY M C K I N N E Y ,
M.D.
Memphis, Tennessee
The use of curare in cataract surgery has not been universally accepted, possibly be cause of the fear of complications or the necessity for the assistance of an anesthetist for its administration. It is the purpose of this communication to present a simplified technique of curare administration which has eliminated the need for an anesthetist and has been without the slightest untoward re action in ISO cases of cataract extraction. The advantage of a quiet eye in a relaxed patient during cataract surgery needs no exposition. Curare is a valuable aid in se curing this. The drug has for the ophthal mologist the happy property of paralyzing the muscles about the eye in lower dosages than are required for paralysis of the other skeletal muscles. It has been found that increasing doses injected intravenously produce first paralysis of the eye and facial muscles and then in order, those of the pharynx, larynx, and ex tremities. As the dose is increased, the inter costal muscles and lastly the diaphragm are paralyzed. The paralysis of the ocular muscles occurs not only at a lower dosage but last longer than the paralysis of the other skeletal muscles. The effect on the ocular muscles of a single intravenous in jection of curare reaches its maximum in about four minutes, continues for 20 to 25 minutes, and then falls off rapidly. Kirby 1 and Clark 2 were the first to make use of this selective effect in ophthalmic surgery. Others have confirmed their ob* From the Department of Ophthalmology, Uni versity of Tennessee College of Medicine, John Gaston Hospital, and Memphis Eye, Ear, Nose, and Throat Hospital, Memphis, Tennessee.
servations. Cordes and Mullen3 and Hender son4 have reviewed the literature, giving a thorough coverage of the history of the dis covery of curare and its evolution from a medical curiosity to a useful aid to ocular akinesia. MODE OF ACTION OF CURARE
The pharmacodynamics of curare have been extensively treated in previous publica tions.1· 3 ' 5 We may summarize by noting that curare acts by way of the blood stream to eliminate the response of individual striated muscle fibers to the acetylcholine liberated at the myoneural junction. Very large doses block the response of smooth muscle fibers also. It is interesting to compare this action with that of procaine. The latter has the property of blocking the production of acetylcholine at the myoneural junction. The paralysis produced by procaine may not be complete because of insufficient saturation of the nerve or because excessive nerve im pulses from above may get through to the myoneural junction in the very apprehensive patient. That the production of acetylcholine is not always completely suppressed by procaine injections is often observed clinically. Ap parently effective O'Brien or Van Lint akinesia may not prevent squeezing of the lids from fright or painful stimulus. Retrobulbar injections of procaine regularly do not produce complete paralysis of the extraocular muscles even when reinforced by epinephrine and hyaluronidase. The paralysis produced by curare is not affected by the greater production of acetyl choline from efferent motor impulses be-
697
698
OSCAR DAHLENE AND J. WESLEY McKINNEY
cause the muscle fibers are rendered incapa ble of contracting; however, much acetylcholine is produced at the myoneural junc^ tion. Thus, there is greater security in the paralysis produced by curare than in that produced by procaine. Kirby,ç Barraquer, 7 Henderson, 4 and others have depended entirely on curare for securing paralysis of the extraocular muscles. On the other hand, Cordes and Mullen3 have merely added curare to their routine Van Lint akinesia and retrobulbar procaine injec tion. To combine the action of curare and pro caine seems logical, if, in fact, the two drugs act synergistically. No experimental evidence for this synergism could be found, but clini cally it is readily demonstrable.
however, that, on occasion, patients in whom four cc. or more were required com plained of a mild sense of suffocation, which caused a little apprehension on the part of the patient and surgeon. The symptom al ways passed off quickly, however, and the patient was easily relieved by oxygen blown over the mouth under the drapes. This inconvenience led us to resume the use of the retrobulbar injection of procaine epinephrine and hyaluronidase followed by injection of curare, one cc. at a time until the desired effect was obtained. It was soon apparent that only two to three cc. of curare were required rather than the usual three to four cc. when curare was depended upon alone. Before beginning the injections of curare, the effect of the retrobulbar procaine was CLINICAL OBSERVATIONS assessed. The patient's ability to rotate the We were led to undertake the use of eye on command was extremely variable. In curare in cataract surgery by the evident ad dividual responses varied from almost com vantages of its use as set forth by Kirby.6 plete inability to rotate the eye in some cases Initially no retrobulbar injection was used. to a response with wide excursions of the Curare was injected by intravenous drip eye. in others. Curare was then given, one under the control of an anesthetist. One cc. cc. at a time. Although the dosage required was injected at a time at four-minute inter was less, paralysis was the same as with vals until the desired effect was obtained. It curare alone. In making our observations we soon ig was found that the average dose of curare necessary for the effective paralysis of the nored the orbicularis muscle, in view of the extraocular muscles ranged between three to fact that the effect of curare on this muscle four cc. of d-tubocurarine (3.0 mg. per cc. closely parallels its effect on the extraocular or 20 units per cc.) Occasionally five cc. and muscles. It is also more convenient to have rarely even more than five cc. were required. the speculum in place while observing the Preoperative medication consisted of 75 ocular rotations. Furthermore, the tonus of mg. of Demerol and 1/150 gr. of atropine the extraocular muscles is a much more im portant factor than contraction of the orbi given subcutaneously. From time to time during the curarization cularis in producing the expulsive force re and before the beginning of the operation, sponsible for complications during the time the patient was asked to look upward, down that the eye is opened. Since the reduced dosage of curare (two ward, and horizontally. Upward movements were first abolished, then downward, and to three c c ) , given one cc. at a time after finally horizontal rotations. It was not con procaine injections, had proved effective it sidered necessary to abolish completely all was decided to try two cc, given at a single horizontal rotation or the slight rotatory injection. This dose is one-half that which had been noted to cause a sense of suffoca movement which usually remained. No serious complication was encoun tion in certain of those cases wherein curare tered using this technique. It was noted, was used without retrobulbar procaine. The
CURARE ADMINISTRATION extraocular muscle paralysis produced by this rapid injection of low dosage proved to be equal to that produced by curare alone or retrobulbar procaine and curare administered more slowly. Two parallel series of cases were then set up. In each series, two cc. of curare were injected at one time and no more. A total of 82 cataract extractions were performed using a rapid intravenous drip of curare in fivepercent glucose solution. After all the curare had entered the vein, the drip was continued at a reduced rate throughout the operation, while the anesthetist sat by the patient. In the other series, 68 cataract extractions were performed wherein the curare Was given as a single intravenous injection by the circulat ing nurse. Both methods were equally effec tive. The antidote Tensilon (N-ethyl'M-hydroxyphenyl'-N, N diethylammonium bro mide) and oxygen were kept in readiness but never used. No untoward symptoms were noted in the ISO cases observed. PRESENT TECHNIQUE
Curare has been considered by us to be merely an addition to the medications used for control of the eye and the patient to be operated upon. Premedication consists of three gr. of sodium amytal, SO to 100 mg. of Demerol, and 1/150 gr. of atropine. Oc casionally, in the case of a large, tense patient, an additional 50 mg. of Demerol is given intravenously along with the curare. The installation of cocaine (four percent) is begun in the patient's room and continued in the operating room. Routine O'Brien akinesia and retrobulbar injection of procaine, epinephrine, and hyaluronidase are per formed. The operation is begun immediately upon the completion of the retrobulbar injection. The conjunctival flap is dissected, and troublesome bleeding points cauterized. The superior rectus bridal suture is inserted and secured so as to rotate the eye to the position desired. When everything is ready for the
699
incision into the anterior chamber, two cc. of curare are injected rapidly into the vein of the arm. Observations of the ocular rotations are no longer made. Since the effect of curare reaches its maximum within four minutes and lasts 20 to 25 minutes, the eye and the patient arrive at the maximum relaxation at about the time the sutures have been placed and the iridotomy completed. The surgeon, therefore, need not hurry because he can be sure of adequate time even if complications should arise. COMMENTS
The oustanding advantages of curare ad ministration are -the immobility of the eye and the absence of expulsive force which it assures. It is entirely feasible, after the lens has been removed, to lift up the corneal flap and inspect the vitreous directly. The vitre ous face may be found to be only slightly convex or even concave, indicating the ab sence of vitreous pressure. In no case have we seen vitreous well up and burst after the lens is removed, even in the very bad actors on our charity service. Remnants of a torn capsule may be grasped and removed under direct vision. Collateral benefits of curare are a relaxed surgeon and an almost unconcerned patient. The intelligent patient who comes to the operating room awake despite the premedica tion and afraid that he might make a move during a crucial stage of the operation, loses his apprehension, relaxes, and may even go to sleep after the curare is injected. The complete absence of untoward side reactions to the injection of two cc. of curare was gratifying. Patients operated upon ranged in age from 31 to 86 years. The usual degenerative conditions of the elderly were encountered. Two moderately severe asthmatics had no difficulty. Preoperative medication with 1/150 gr. of atropine pre vented bronchospasm and excessive secre tions. No cases of myasthenia gravis were seen.
700
W. LEYDHECKER
Vitreous was lost in seven cases (4.7 per cent) of 150 cases operated upon. In none of these was forward movement of the vitre ous body accountable for the loss. Rather, the loss was attributable to factors such as undue adhesion of vitreous face to lens (both eyes of same patient), surgical accidents, or temporary ineptitude of the surgeon. CONCLUSIONS
Our observations on the use of curare in 150 cataract extractions confirm the opinion of others that it is a valuable adjunct for the better control of the patient who is to undergo cataract surgery.
A reduced dosage of curare (two cc.) act ing synergistically with the procaine of the retrobulbar injection and O'Brien akinesia yielded effective relaxation of the extraocular muscles and eyelids. Preoperative sedatives plus curare yielded a completely relaxed pa tient. No untoward symptom was noted with the small dosage used (one-half the dose previously noted to cause a complaint of mild suffocation). The services of an anesthetist are no longer considered necessary. Hall Street. 921 Exchange Building (3).
REFERENCES
1. Kirby, D. B.: Use of curare in cataract surgery. Tr. Sect. Ophth. A.M.A., 1949, pp. 279-293. 2. Clark, W. B. : Use of curare as an adjuvant in cataract surgery. Watson Gaily Eye Foundation Quart., 1:34, 1949. 3. Cordes, F. G, and Mullen, R. S. : The use of curare in cataract surgery. Am. J. Ophth., 34 :SS7-S64 (Apr.) 1951. 4. Henderson, J. W. : Curare akinesia in cataract operations. Am. J. Ophth., 36 :781-788 (June) 1953. 5. Drucker, A. P., Sadove, M. S., and Unna, K. R. : Ophthalmic studies of curare and curarelike drugs in man. Am. J. Ophth., 34:543-553 (Apr.) 1951. 6. Kirby, D. B. : Curare in cataract surgery : Five years' experience. Tr. Sect. Ophth. A.M.A., 1952. 7. Barraquer Moner, J. I. : The present technic and results of the use of curare in ocular surgery. Am. J. Ophth., 36:789-794 (June) 1953.
INFLUENCE OF COFFEE UPON OCULAR TENSION* I N NORMAL A N D I N GLAUCOMATOUS EYES W.
LEYDHECKER,
M.D.
Bonn, Germany
We have been taught that glaucoma pa tients should not drink coffee because this would increase the ocular tension. In coffee drinking two factors could influence the tension, caffeine and water. The effect of water drinking upon the ocular tension has been the subject of many publications1"21 and was studied in detail in my own com munications.22-27 Caffeine has been applied as a provocative test,28-36 but the limits between physiologic and pathologic reactions of the tension have not been clear so that ♦From the University Eye Clinic, Director: Prof. H. K. Müller.
evaluation of the test was difficult. I have applied both the caffeine and the water-drinking tests to a number of persons with normal and glaucomatous eyes in order to prove their reliability and to study the hygienics of glaucoma. EFFECTS OF CAFFEINE ON NORMAL EYES
In 198 eyes of 109 healthy subjects a pro vocative test with caffeine was performed. Five tests were done with 45 gm. of coffee in 150 cc. water, 11 tests with 0.5 gm. caf feine sodiobenzoate intravenously, and 182 tests with 0.4 gm. pure caffeine plus 150 cc. water.