SUCCINYLCHOLINE AND ACETAZOLAMIDE (DIAMOX) IN ANAESTHESIA FOR OCULAR SURGERY*

ARTHUB S CABBALLO M D

SUCCINYLCrIOLINE IS the muscle rel~xant of choice for tracheal mtubatlon, and tracheal mtubahon is a reqmslte for a satisfactory general anaesthesm m mtra- ocular surgery However, succmylchohne is known to increase mtraoeular tension In 1955 and 1957 there were reports m the hterature of loss of vitreous occurring during surgery of the open eye when succmylchohne was used m anaesthesia, x,~ with a resultmg loss of vision Succmylchohne also represented a serious hazard to patients wah glaucoma s-7

A study was undertaken m the l~epartment of Anaesthesm of the Wmmpeg General Hospital to determine whether prewous admmrstratlon of acetazolamlde ( Dlamox ) would prevent the dangerous rise m mtraocular pressure accompanying the use of succmylcholme in anaesthesia If the results proved successful, then this valuable muscle relaxant could be safely employed in cataract extractions and corneal transplants, and m patients suffering from glaucoma

The most important factor determining the internal pressure of the eye iS the aqueous humour, the hydrostatic pressure of the blood accounting for only one-quarter of the total mtraocular tension Formed in the clhary processes behind the ms by a combination of diffusion and actwe transport, m which the enzyme carbomc anhydrase plays an important chamber and leaves the eye by the canal of

Rapid mcreases m mtraocular pressure flow of the aqueous m most cases. The

role, the aqueous fills the posterior Schlemm (Fig 1) s-ll are due to interference with the out- normal eye has a great capacity for

compensating any increase m mtraocular pressure, smaply by increasing the rate of outflow of the aqueous The osmotic pressure of the aqueous humour is higher than the osmotic pressure of the blood If we compare the composition of the aqueous with that of blood, we o~serve that while the amount of protein of the aqueous is as low as 0 02 gin/100 ml, and the glucose, urea, and bicarbonate concentrations are lower than m blood, those of the chlorides, sodmm, and lactate are higher The aqueous is the only means of nutntxon of the lens and cornea, smce they are devoxd of blood supply 12-14

The normal mtraocular pressure has an accepted physxologlcal range of 10 to 22 mm Hg above atmospheric pressure. There is a variation of 2 to 3 mm. Hg dady for each mdlvadual, the higher readings being obtained m the early hours of the morning, and the lower ones early in the evening Position also accounts for a difference of 2 to 3 mm Hg, the reading being higher during recumbency than m a standing position 15

*From the Department of Anaesthesia, Wmmpeg General Hospital Presented m part at the annual meeting of the Western Dwlslon, Canadian Anaesthetists' Socmty, March, 1965

486

Can Anaes Soc J, vol 12, no 5, September, 1965

A CARBALLO SUCCINYLCI-IOIXNE AND AG--~ETAZOLA1VIIDE 487

The respiratory movements also affect mtraocular pressure Deep msp~r~bon may lower ~t by as much as 5 mm Hg, while ~t ~s increased during exptr~bon. The pulse beat produces a physaolog~cal oscfl|araon o~ 1 to 2 mm Hg. Vana~aons m arterial blood pressure are reflected m small but rapid changes m the ocular tensaon w~th a tnne delay of only one-tenth of a second. Obvaously thas as due to

Co r ~

Canal of $ch[e~m

~r-ens

/ Po.st~r'~ tot chamber

Cz 2 zaa~' pl"~=eslz

r ~ary body Vx t r e o u s

Fic~n~E 1 The ;ingle of the eye

changes an the volume of blood circulating through the eye, and not to over- production of aqueous humour In sustained arteraal hypertension, the ocular tension returns to its normal levels after a period of adaptation

Obstructaon to the venous return from the head increases the ocular pressure, and so does coughing, sneezing, or stralmng This can be of lmportan?e during surgery of the open eye 16 1~

If the outflow of the aqueous stops completely, the mtraocular pressure should rise only to the effectave filtrataon pressure of the capfi|ary bed, which is about 30 mm Hg, and yet m closed angle glaucoma, rea,chng,~ above 80 and 90 have been reported It as interesting to note m this cormectlon that the hydrostatic pressure an the capillaries of the eye is 75 mm Hg~ the osmotic pressure otE the blood and the mtraocular pressure being the only factors opposing it When the carcu]ataon stops at the moment of death the mtraocular p,ressure falls to 5 mm Hg and stays at this level for a short period, then gradually drops to zero Hypo- ventfiat~on, hypoxla, and hypercapnoea aH elevate the tension m the eye Oxll the contrary, hyperventflatlon, high oxygen tension, and hypocapnoea lower the mtraocular tensaon Hypoprotemaemm has practically no effect x6

I

Endotraeheal mtubataon by ~tself elevates the Ocular pressure Retrobulbar anaesthesia and digital pressure on the eye are two very effectave means m the I hands of the ophthalmologist for reducing the mtraocular pressure 18-~.4 [

Rapid mgeshon of one htre of sahne has no effect on the eye, but ~apld ingestion of one htre of water elevates the pressure There is no agreement as to

'488 CANADIAN ANAESTHETISTS' SOCmTY ]OUnN~L

where control of the mtraocular tenmons he~, although the hypothalamus has been imphcated The role of the sympathehq and parasympathetic fibres is also contro- versm125-~

There are two methods of measuring mtraoeular pressure man0metry, which revolves placing a needle m the an~enol chamber, and tonometry, used for recordmg the pressure necessary to depress the cornea Tonometersl are based on two different principles lndentahon and applanataon The first depends on the fact that the Impressibility of the cornea depends mainly on the Ocular tenmon, while the cornealng:dlty plays but a minor role Indentatxon t0nometers are stated for readings m the recumbent pos~tlon The Schlotz's tonometer is the most commonly used Applanahon tonometers are best used with the patient an the erect posmon 34

Let us now rewew the effect of the anaesthetic agents on the mtraocular pressure Cyelopropane, dlethyl ether, chloroform, halothane, tnehlorethylene, and dxvmyl ether lower the intraocular pressure The effect is mo~e pronounced m deep planes of surgical anaesthesm, owl~g to the relaxahon of the extraocular muscles and the consequent facd:tat:on o~ aqueous outflow Ethylene doesnot alter the tens:on, and mtrous oxide has been reported to raise : t =s,a~-z9

Morphine, mepenchne, and the short-actlng and ultra-short-acting barbmtrates lower the mtraocular tens:on by faclhtatmg the aqueous outflow Pre-anaesthehc medlcahon at the usual doses of nareot:c and atropine reduces the mtraocular pressure of the normal eye by about 10 per q~nt :e,21,2s,29,40-42 Atropine alone, when gwen systemahcally, produces a shght rise m mtraocular pressure, owing to capillary dllatahon The concomitant mydnasxs does not affect the normal eye, but m the patient w~th closed angle glaucoma tt can produce an acute elevation of the mtraocular pressure For this reason atropine has been indiscriminately wathdrawn from the pre-anaesthetic medlc~tlon of glaucomatous patients Actually :t IS only dangerous ~or the pahent wath narrow angle glaucoma aT,4z

There is no agreement as to the effects of scopolamine on the ocular pressure, but It IS known to produce a greater degree ot mydrmms than atropine Acetyl- chohne and the antl-chohnesterases elevate the ocular tenmon by producing vasoddatahon m the eye and by stxmulatmg the contrachon of the rect: muscles Epinephrine m small doses elevates the mtraocular pressure by shlmulatmg only the beta receptors, while at higher concent~ataons it reduces the tension by means of vasoconstnct:on produced when the alpha receptors are also stimulated 4~-4T

Finally, the non-depolarizing muscle relaxants, curare and gallanmae, relax the extraocular musculature, brmgmg the lntraocular pressure doWn, while the depolarizing agents, decamethonlum and Succmylchohne, elevate it ae,45,48-55

It has been accepted for some t:me that the mechamsm of this elevat:on IS a sustained contract:on of the extraocular mnscles, and that they reatet to succmyl- chohne xn a fashion different from the other ,,keletal muscles W~hde the ,lat~er s~_lffer only momentary fasc:culatlons followed by relaxahon, the extraocular muscles respond with a sustained contracl~lon, lust as the belly muscles of b~r!ds and frogs do ~ =8 ~= ~3 ~-~:

Electromyography o~ the human extraocular muscles has demonstrated that the motor umt of these fibres ~s much smaller than that of the sl~eletal muscles

A CARBALLO SUCCINYLCHO~.~E AND ACE'IIAZOI.,AI~I~E 489

and also that it is much simpler, so it can fire at greater frequency The mner- ration ratio of the soleus, for example, as 1 nerve fibre to 100 or 150 muscle fibres, compared to 1 5 for the extraocular muscles, and thxs ratio as characteristic of muscles used for precise and dehcate movements Skeletal muscle at rest shows no recordable potentml, while the extraocular muscles are seldom electrically silent 68-65 To some authors thas indicates that the extraocular muscles~ simply require a higher dose of succmylcholme to achieve the paralysis obtained m the skeletal muscle ~9

It has recently been shown that cutting the extraocular muscles does not prevent the rise m mtraocular pressure caused by ,~uccmy|chohne, and it is belaeved now that the direct vasodllatatory effect of the depolarizing muscle relaxant on the mtrabulbar vessels is the mare factor i esponsable for the rise m mtraocular pressure, whale the contracture of the extraocular muscles as only secondarily responsable 66-6s Since the mtraocular pressure is increased by succmylchohne, at seemed advasable to avoid ats use during surgery of the open eye and m glaucoma Some authors found that the use of succlnylchohne was only dangerous ff at was admmastered after the eye was open Other investigators attempted to find a soluhon to thas problem, some by using hexafluoremum (Mylaxen) to prevent the muscular fasclculataons caused by succmylcholme, others by adrmmstermg the drug very slowly, and Stdl others by conducting the general anaesthesm m deep planes, or by rejection of a local anaesthehc m the retrobulbar space and by applying pressure on the eye The greatest reduc- taons m mtraocular pressure were achaeved by the use of hypertomc soluhons, thus intravenous Sorbatol, Dextran, and particularly urea and manmtol have been used ruth success m glaucoma ~-~ 2o 39 6~ 68-76 For other pubhcahons on ttae subject, see references 91 to 123

Acetazolamade (Dmmox) used intravenously is known to reduce mtraocular pressure, starting to act wathm 2 minutes and reaching ats greatest effect w~thln 20 minutes This potent drug, decreasing the aqueous flow by 50 per cent, is easy to employ an comparison ruth the cumbeasome hypertomc solutaons Acet,a- zolam~de has no achon on the pupd, nor does at alter the outflow of the aqueous It completely inhibits the carbomc anhydrase actmty of the cdmry body and arts, when given oaally or intravenously The carbomc anhydrase mhab~hon goes hand m hand wath a notaceable reduchon m the ocular tensaon r5 7 7 - 8 9

Acetazolamade as a non-bactenostatac sulphonamade denvatwe It paoduces d~uresas and alkahmzahon of the urine, reducing a state of mild acldosas It results an renal loss of b~cal.bonate whach carries ruth 1I water, sodaum, and potassium Thas as the reason for ~ts mdacahon m oedema, congestave heart failure, and obesity In glaucoma at 1educes the mtraocular tensaon by slowing the rate of .formation of aqueous humour It interferes ruth ~he ehmmahon of carbon daoxlde by the lung, but thas is of httle concern, of course, an the anaesthehzed pahent whose respnahons can be easily assisted It a~ contramdacated an renlal acldosas, dehydration, and sodlura or pot'assmm depletaon In large doses, or when gaven over long periods of hme, at can produce drowsiness, dlsonentahotn, fever, ]eukopema, and rashes But these will not occur when a single dose of 509 mg ~s admmastered Acetazolamlde m aqueous so~lutaon for intravenous u~se

490 CANADIAN ANAESTHE'IrlSTS' SOCIETY JOUBNAL

as alkahne, so care must be taken to avoad extravasataon, bt~t it produces no slough of the subcutaneous txssues, It Can be safely gxven intramuscularly 75,so,90

MA ~mAL

The mtraocular pressure of fif!ty anaesthetxzed pahents was studied The sublects were chosen at random All were 20 years or older, and none of those included had glaucoma The surgacal procedures, all of which gave easy access to the eye, are hsted an Table I

TABLE I

SURGICAL PROCEDURES INCLUDED IN THE STUDY

Surglcal procedure No of cases

Ophthalmological 7 Gastro-~ntestanal 32 Orthopedic 6 E N T 3 Urologmal 2

Total 50

M ~i THOD

Pre-anaesthetlc medacatlon consisting of mependme 50 mg and atropine 0 6 mg was gwen intramuscularly one hour pre-operatlvely to each of the pataents Induction of anaesthesia was carned out wath sodmm thaopentone an doses of 200 to 500 mg to produce sIeep In 25 of the 50 pahents (the test group) mductaon was preceded by a rap~d ml~ct~on of 500 mg acetazolamlde chssolved an 5 to 10 ml sterile dastflled water The mtraocular pressure was then measured wath a Schmtz's tonometer wath a 5 5 gm plunger load FoUowmg thas, the patient was oxygenated w~th a mask

Two minutes after acetazolamade had been admamstered, a second reading was taken Succmylcholme 60 mg was gwen intravenously, and the lungs were inflated with oxygen A third reading was recorded at the peak of the s tlons of the muscles of the face Traclheal mtubatmn followed, wath manually controlled' resparataon using a mtxture of oxygen at 3 htres p~r minute, nitrous oxade at 3 htres per minute, and halothane A ctrcle absorber Isystem using the semi-closed techmque and a Fluotec vaporizer outside the ctrde were employed an every case Ocular tensions were then recorded every minute for at least 5 tames In the 25 pataents not recewmg acetazolamade (the colltrol group), the mtraocular pressure was taken after Pentot]~al mductmn and agam, I two minutes later Then succmylchohne was gaven~ and the reading repeated at the peak of facxal fasc~culataons, and every minute from then on for ,at least 5 times Doses were as m the test group

A CARBALLO SUCCINYLCI~OLINE AND ACETAZOLAM_IDE ~t91

RESULTS

The mean values of each successwe group of 25 observations were calculated The standard deviations and upper hmats were obtained for the basal tensi0ns of the two series The successwe readmgs were compared to the upper lm~ltS It was clear then that there were no sagmficant devmtmns an the series ~,ath acetazolamxde, but m the control series slgmfieant elevations over the up )er hmlts were found m 19 out of the 25 observatmns made during fascmulatl ins and m 17 out of the 25 made one mmute later (Tables ]I and III) The rn, ;an estimates were obtained by adding all values obtained at samxlar moments ' n d dwxdmg the total by the number of observahons, The standard devxat were obtained by subtracting the mean from each reading, squaring each dd ence, summing the resulting squares, dwldmg by one le,~s than the numb& values and tahng the square root Twace the standard devmtmn was added mean estmaate to give the upper hmlt, and subtracted to gave the lower h~ Figure 2 shows the mean estimates for both series

)ns

fer-

of t o

m t

TABLE II

INTRAOCULAR PRESSURES, CONTROL SERIE S PROTOCOL l L

Basal 2 rnm S ch 1 mm 2 mm 3 mm 4 mm 5 mlr~ IOP later fasclc later later later later latet~

Recorded values 14 6 12 2 20 6 18 9 17 3 1 2 2 1 0 2 1 7 3 2 0 6 1 7 3 1 7 3 1 7 3 2 4 4 2 4 4 2 0 6 1 0 2 ~ 8 5 2 0 6 2 4 4 1 8 9 12 2 12~2 24 4 24 4 17 3 15 9 12~2 20 6 18 9 13 4 18 9 18)~' 24 4 20 6 20 6 11 2 15 " 24 4 20 6 15 9 15 9 17 26 6 29 0 18 9 14 6 14 6 22 4 34 5 24 4 17 3 15 9 18 9 18 9 17 3 14 6 15 9 34 4 29 0 18 9 13 4 15 9 15 9 15 9 14 6 15 9 15 9 14 6 17 3 14 6 14 6 15 9 20 6 18 9 14 6 17 3 17 3 24 4 24 4 20 6 10 2 10 2 14 6 17 3 13 4 11 2 10 2 20 6 20 6 18 9 20 6 18 9 29 0 26 6 20 6 15 9 17 3 26 6 20 6 24 4 17 3 18 9 34 5 26 6 20 6 13 4 13 4 17 3 17 3 13 4 13 4 13 4 24 4 26 6 17 3 15 9 17 3 29 0 26 6 14 6 17 3 17 3 2q 0 26 6 18 9

Mean values

14 8 14 4 23 1 22 7 17 8

Standard devtatlon 274 Upper hmlt 2038 Lower hmlt 922

.7 3 14 6

.8 9 14 6

.4 6 17 3 L4 6 10 2 ~8 9 14 6 L8 9 18 9 L5 9 14 6 L4 6 11 2 [4 6 14 6

3 14 6

, 9 15 9 15 9 15 9 t4 6 14 6 18 9 18 9 13 4 11 2 113 4 11 2

6 14 6 17 3 14 6 i17 3 18 9 13 4 13 4 12 2 12 2 13 4 13 4 18 9 18 9

10 2 15 9 12 2

18 14 11 14 15 14 12 14 15 14 17 11 10 14: 12 15 12 12 12 18

16 0 14 8 13 8 i

4 9 2

,i?,~: ,, " ,

Basal IOP

15 9 20 6 17 3 20 6 14 6 17 3 15 9 17 3 17 3 10 2 12 2 12 2 17 3 10 2 14 6 12 2 13 4 14 6 15 9 17 3 11 2 10 2 11 2 13 4 13 4

CANADIAN ANAESTHEa~'S ' SOCIETY JOURNAL:

TABI!.E I I I

I N T R A O C U L A R P R E S S U R E ~ , , T E * , T S E R I E S P R O T O C O L

L

Dmmox S ch effect fascm

....... j ~:,,, ~,,,,,,, ' . . . .

1 mlln 2 m m 3 mm later later later

R~cord~d' values 15 9 18 9 18 9 '18 9 17 3 20 6 20 6 17 3 '18 9 17 3 15 9 15 9 17 3 15 9 15 9 20 6 17 3 18 9 17 3 15 9 13 4 15 9 12 2 13 4 11 2 17 3 17 3 17 3 15 9 15 9 15 9 10 2 10 2 15 9 15 9 15 9 17 3 18 9 14 6 15 9 14 6 14 6 14 6 13 4 12 2 12 2 12 2 8 5 10 2 5 9 10 2 10 2 11 2 8 5 8 5 10 2 11 2 9 4 9 4 11 2 14 6 17 3 18 9 18 9 17 3

7 1 14 6 17 3 14 6 12 2 14 6 17 3 12 2 14 6 12 2 12 2 8 5 8 5 10 2 12 2 13 4 17 3 13 4 10 2 10 2 10 2 12 2 14 6 10 2 12 2 17 3 17 3 14 6 14 6 10 2 15 9 18 9 15 9 15 9 15 9 10 2 10 2 10 2 10 2 7 1 10 2 12 2 12 2 8 5 10 2 15 9 15 9 12 2 10 2 8 5 13 4 10 2 12 2 12 2 10 2 12 2 12 2 13 4 13 4 13 4

14 6 13 9 14 6 Mean values

14 0 13 4 I-

12 9

Standard devtatmn 3 059 Upper hmlt 20 71 Lower hmlt 8 48

. . . . I

4,ram l~tter

11 2 1' 3 1, 9 1, 9 1 : 2 1' 2 1, 6 1 ~ 3 1 : 2

1 1 2

~ 9 1 t 6 10 2 1 ~ 2

g 5 1 2 2 1D2 1 7 3

5 1 2

1 : 2 13 4

5 m m later

1212 17,3 15 9 17,3 13,4 12 2 14 6 17,3 1 2 2 5 9 9~4

12J2 1819 1476 12 2 12 2

8 5 12,2 12 2 17 3 10 2 10 2 11~2 12'2 13 4

1~ 4 13 0 I

DISCUSSION

Rea&ngs subsequent to those obtamed within the five-minute Interval proved to be unnecessary because m all cases obsepced the lntraocular tensions &d not revert to 1-ugh readings after five minutes This fact has been repeatedly corrobo- rated by prevlous pubhcatlons, of different authors who have found that the maxamal effect of a single dose of succmylchohne on mtraocular pressure oecurs within twenty to thn'ty seconds and lasts [rom two to five minutes :1,2

Although a perusal of Figure 2 may lead one to beheve that the mtraocular tension never rose after acetazolamade was gwen, 12 patmnts &d show some rise in ocular tensaon after succlnylcholme despate the carbonm anhydrase mhabl- tor, as can be seen an Table III But these elevations were not slgmficant since they did not go above the calculated upper hmats These results therefore appear to prove the sagmficant value of acetazolamlde as a means of preventing the elevatmns an ocular pressure produced by succmylchohne But ff a practmal conclusmn has to be drawn from this study, the anaesthesmloglst would do better administering the carbomc anhydrase inhibitor intravenously 20 to 30 minutes before the muscle relaxant, and hmatlng the succmylchohne dose to 20 or 30 mg A more rehable control of the mtraocular tensmn can be achieved in

A CABBALLO $UCCINYLCHOLINE AND ACE,FrAZOLAI~mE ~93

th::, manner The fact that glaueomatous pahents have no| been included m the study precludes extension of these conclusions to them

Hg

23 2.2: 21 2O ~9 18 ~7 ~6 ~5 14 ~3

12 lJ

A B C 3 4 5 Fmum~ 2 A - - B a s a l l O P B - - Two minutes later

C = Succmylchohne facial fascIculatmns The sequence of events here is as follows m A,

acetazolamlde and Pentothal were given and the eye tensmn was recorded when the patient was asleep In B, two minutes after A, the intraoeular pressure was taken and succmylchohne given In C, the oculall tensmn was measured dunng muscular fascieulat:ons of the face Then the patients were mtubated and given halothane, nitrous oxide, and oxygen whtle the mtrao~ular ] ressurep was taken every minute for 5 minutes Bell ween A and B, and between B and C, the pahents were given oxygen by mask

S u ~ ~ ARY

A review of the physlology and pharmacology of mtraocular pressure as related to anaesthesia has been presented A study has been undertaken to determine whethe: previously administered aeetazolamlde would prevent lthe dangerous rise m mtraocular pressure accompanying the use of succlnylchotme m anaesthesia, so that succmylchohne might be safely employed m cataract extractions and co:neal transplants, and an pahents sufltenng from glaucoma ,

The ocular tensions of two series of 25 anaesthehzed patients, have been stud~ed Acetazolam:de (D:amox) and sueemyleholme were given to the test group, and succmylchohne only to the control grou P The mean values of Ithe success:re readings, the standard deviations, and the upper and lower hm:ts of the basal observatmns have been calculated The results are given m tames and the mean va]ues are ,expressed graphically to fac:htate their eompanison

494 CANADIAN" AN'AESTHETIS rs SOCIETY ~OURNAL

Slgmficant dewatmns have been ~ound after succmylchohne alone, but not when acetazolamlde was g~ven beforie, the succmylchohne The readings m the test group remained within the accepted normal hm~ts for the mtraocu]ar tensmn

Tins study therefore mdmates the I?ract~lcal value of acetazolam~de as a means of avoiding the s~gmficant elevatmns m mtraocular tensions produced by succmylchohne

Nous avons pr~sent~ une revue de la physlologle et de la pharmacologm de la pressrun mtraoculalre en rapport avlec ranesth~sm Nous Irons entrepns une ~tude pour pr~clser sl l'admmistra~laon pr~alable d'ac&azolamlde (Dmmox) pourralt pr~vemr r~l~vatmn dangereuse de la pressrun mtra0culmre qm accom- pagne l'usage de la succmylcholme au cours de l anesthesm De cette faqon, ,11 sermt posmble d'employer la succmylchohne, en toute sdcunt(, au cours de l'ex- tractmn de cataractes, de greffes de (Iorn~e et chez les malades qm souffrent d e g l a u c o m e

Nous avons ~tud~ les tensmns oculatres de deux s~nes de 25 malades anes- th~slSs Nous avons donn~ l'ac~tazolamlde (Dlamox) et la succmylchohne au groupe h r~tude et la succmylchohne seule au groupe contr61~ Nous avons calcul~ les valeurs moyennes des lectures sucCesswes, les ddwatmns standards, les hmltes sup~neures et mf~neures des obserwatmns de base Nous donnons les r~sultats sur les tableaux et, pour faclhte~ leur comparalson, nous expnmons les valeurs moyennes par des graphlques Nous avons observ$ des variations lmportantes lorsque la succmyichohne &alt employee seule, rams non dans la sdne de su]ets ~tudl~s, chez qm l'ac~tazolam~de avaait ~t~ donn~e avant la suCcmylchohne Chez ce dermer groupe, les lectures sont demem ~es dans les hmltes normales accept~es pour la tension mtraoculmre

En consequence, fl sembie bran qute cette ~tude prouve la valeur pratique de l'ac~tazolamxde (Dmmox) comme moyen d'~vlter les 4ld~atlons ~mportantes mtraoculalres prodmtes par ]a succlny,~chohne

A CKN O~VLEDG MENTS

I am indebted to Dr D M H Huggms for her numerorus suggestions and gmdanee, and to Drs H Reed and K Grant for their mval~uable co-operatmn

REFERENCES

1 LINCOFF, H A, Bm~mn~, C M, & DET~rOE, A G The Effect of l~uccmylchollne on the Extraocu]ar Muscles Am J Opth 43 440 (1947)

2 SCHWAaTZ, H & DE ROEZa-I, A EffeCt of Intraocular Pressure m Human Beings Anes- thesiology 19 112 (1958)

3 A'rxn~soN, Yg S Anesthesia for Glaucoma Surgery New York ] Med 56 205 (1956) 4 LEWALLEN, W M & HICKS, B L The Use of Succmylchohne in Ocular Surgery Am

J Ophth 49 773(1960) 5 MIET-~S, C A, HAGUE, E B, & C~BONE, I) J Use of General Anesthema and Muscle

Relaxants m Cataract Surgery Am J Ophlh 47 487 (1959) 6 RrwcHtrN, M H Chome of Anesthesl[a m Ophthalmm Surgery Anaesth & Analg 37

75 (1958)

A CARBAIJ~O SUC~INYLCHOLINE AND ACETL&ZOLA~t~IDE 495

7 ROCHE, ] R Research m the Use of Curare for Ocular Surgery Am J Ophth 33 91 ( 1950 )

8 FRANGOrS, Wall of ~h'e NEETENS. A, & ~OLLETTE, J M Mmxorad:lographm Study of the Inner Schlemm s Canal Am J Ophth 40 491 (19515)

9 F~T~:nENWALD, J S Fonnahon oF the Intraocular Flmd Am J Ophth 32 9 (1949) 10 FRIEDENWALD, J S & STIEHLER. R D Clrculahon of Aqr, tueous vii A Mechamsm of

Secretmn of the Intraocular FlUid A M A Arch Ophth 20 761 (1938) 11 WmGHr, S Apphed Physiology, 10th ed London Oxford Umv Press (1962) 12 ADLER, F H Physiology of the Eye Chmcal Appllcahon, 3rd ed St Lores Mosby

( 1959 ) 13 . . . . Textbook of Ophthalmology, 7th ed Phlladelphm Saunders (1962) 14 KINSEY, V E Comparahve Chemistry of Aqueous Hum0ur m Posterior and Anterior

Chambers of Rabbit Eye A M A Arch Ophth 50 401 (1953) 15 GALIN, M A & DAVIDSON, R Dmrehcs m Ophthalmology New York ~ Med 62

2831 (1962) 16 DUNCALF, D & WEITZNER, S W Venhlatmn and Hypercapnea on Intraocular Presstnoe

Anaesth & Analg 42 232 (1963) 17 Macro, F J Vascular Pressure Relatmnshlps and the Intr~ocular Pressure A M A Arch

Ophth 65 571 (1961) 18 ATmSSON, W S Local Anesthesm m Ophthalmology Am J Ophth 31 1607 (1948) 19 BECXER, B Annual Revmw of Glaucoma, 1955-1956 A MA Arch Ophth 56 898

( 1956 ) 20 DEL PIZZO, A & GumA, F Succmylchohne m Cataract Surgery Anaesth & Analg 40

686 ( 1961 ) 21 EvEru~]-r, W G, VEY, E K, & VEENIS, C Y Factors m Reducing Ocular Tension

prior to Intraocular Surgery Tr Am Acad Ophth 63 286 (1959) 22 Gan~FORD, H A Study of the Effect of Retrobulbar Ane,i, thesla m the Ocular Tensmn

and the Vitreous Pressure Am J Ophth 32 1359 (1949) 23 KnascrI, R E & STEINMAN, W Digital Pressure, an Important Safeguard m Cataract

Smgery A M A Arch Ophth 54 697(1955) 24 SNYDACKER, D, DEUTSCH, W E, & BAYARD, W VanouIs Anesthetm Agents Used m

Retrobulba~ Injectmns A M A Arch Ophth 5I 473 (19514) 25 BECI~Erl, B & C~mmsTENSEN, R E Water Dnnkmg and Tonography m the Dmgno*,ls

of Glaucoma A M A Arch Ophth 56 321 (1956) 26 GALIN, M A, AIZAWA, F , & McLEAN, J M Evaluatr~l)n o{ the Water Provocahve

Test Am J Ophth 51 451 (1961) 27 GALIN, M A, AxzAW,% F , & McLEAN, ~ M The Water provocahve Test m Glaucoma-

tous Patients Am J Ophth 52 15 (1961) 28 KORNBLUETH, W, ALADJEMOFF, L, MAGORA, F, & GAB]~AY, A Influence of General

Anesthesm on Intraocular Pressure m Man A M A A~eh 0phth 61 84 (1959) 29 SCH~EIaL, E & STErNBEaC, B Role o~ the Dmneephalon [In Regulating Ocular Tensmln

Am J Ophth 31 155(1948) 30 Determmatmn of Ocular Tensmn and Rigidity m Rabbits Am ] Ophth 29 1400

( 1946 ) 31 Central Control of Intraocular Pressure by Achve Pnnclples Am J Ophth 3I

1097 (1948) 32 VON SALLMAN, L , MACRI, F J , V~TANKO, T, & GRIMES, P 2~ Some Mechamsms of

Centrally Induced Eye Pressure Responses Am J Oph!th 42 130 (1956) 33 yon SALLMANN, L & LOVENSTEIN Responses of Intraocular Pressure, Blood Pressure

and Cutaneous Vessels to Elechm Shmulatmn an the Dmncephalon Am ] Ophth 39 11 (1955)

34 MOSES, R A & BECKER, B Chnmal Tonography, The Scleral .Rigidity Correctmn Am ] Ophth 45 196(1958)

35 A~m~',IL ] The Pharmacology of Anesthehc Drugs, 4th ed Springfield Thomas (1960) 36 Cor~oE, J H JR & DmPPs, R D Hlstamme-Lke Actmn of Curare and Tubocurarme

Injected Intracutaneously and Intraartenally m Man Anesthe,,mlogy 7 260 (1946) 37 MAGOnA, F & COLLINS, V J The Influence of General Anesthehc Agents on Intra-

ocular Pressure m Man A M A Arch Ophth 66 806 (1961) 38 SCHWARTZ, H Chloroform Anesthesm for Ophthalmm Exammatmn Am J Ophth 4,3

27 (1957)

496 CANADIAN ANAESTHE31C'ISTS' SOCIETY JOLI1ANAL

39 WYNA:~DS, J E & CaOW~LL, D E Intraocular Tension m Assoct~hon with Succmyl- chohne and Endotracheal Intuba~lon A Prehmmary Report Caned Anaesth Soc J 7 39 (1960)

40 DE ROETTH, A JR & SCaWAnTZ, H Aql]ueou,, Humour Dynamics m Glaucoma A M A Arch Ophth 55 755 (1956)

41 LtrND, P C Sur:tal Sodmm A New Intravenous Anesthetic Agen~ Am ] Surg 81 637 ( 1951 )

42 THOMAS, G J & McCAsL~, M F PentothM Sodmm m Ophthalrmc Surgery AM A Arch Ophth 37 452 (1947)

43 GOTn, A Medical Pharmacology, 1st ed St Lores Mosby (1961) 44 BAnNE'r'r, A Ocular Effects of Methonmm Compounds Bnt J Oph~h 36 593 (1952) 45 COLLE, J C, DVm~-ELDEn, P M, & DUr~-LLDEn, W S Studies on the Intraocular

Pressure ] Physlol 71 i (1931) 46 FmEDF.NWALD, ] S & BUSCHKE, W Th,l~ Role of Epinephrine an t~e Formation of the

Intraocular Flmd Am ] Ophth 24 1105 (1941) 47 LEOFOLD, I H , Hr~DGv.S, T R Jr:, MONTANA, ~, & KmSHNA, N Local Adm:mstratmn

of Anhchohnesterase Agents m Ocular Mya,,thema Gravls A M A. Arch Ophth 63 544 ( 1960 )

48 ADAMSO~r, D C & K:NSMAN, F M Shcemylchohne Chloride m Anaesthesm Anaes- thesia7 166 (][952)

49 ACAlaWAL, L P & MaTrnm, S P, CUrare m Ocular Surgery Report of 25 Cases Bnt J Ophth 36 603(1952)

50 Bo:m~rE, ] G, COLL:~, H O ~, & SOM~.aS, G F Succmylchohne (Succmoylcho- hne) Muscle-Relaxant of Short Actmn Lancet 1 1225 (1952)

51 voN D~mDEL, O & TH~SLV.rF, S Chmeal Expermnce wlth Succmylchohne Iodide A New Muscular Relaxant Anaesth & An dg 31 250 (1952)

52 DmLON, ] B, SABAWALA, P , TAYLOn, D/ B, & G:mTER, R Depolarmmg Neuromuscu- lar Blocking Agents and Intraocular Plessure m Vwo Anesthesmlogy 18 439 (1957)

53 Actmn of Succmylcholme on Extraocular Muscles and Intraocular Pressure Anes- thesmlogy i8 44 (1957)

54 Dr~trc~r~R, A P, SADOVE, M S, & UNI~A, I~, R Ophthalmm Studms of Curare and Curare-Like Drugs m Man Am ] Ophl~h 34 543 (1951)

55 HAnms, L C & DmFPs, R D Use of Decamethonmm Bromide for the Productmn of Muscular Relaxatmn Anesthesiology /1 215 (1950)

56 CALVF.nT, R & MoncA_n, D I( Effect otf Suxamethonmm on Blood pressure Anaesthesm 9 196 ( 1954 )

57 CRAYT~Om~, N W B, ROTTF, N S ~ , H S, & DmPPs, R D Thel Effect of Succmyl- choline on Intraocular Pressure m Adults, Infants and Chddt:en during General Anesthes:a Anesthesmlogy2I 59 (19613)

58 DUg~-ELDF_aq, S W & DUKE-ELDER, P M The Chnmal Slgntficance of the Ocular Musculature with Specml Reference rio the Intraocular Pressure and the C~rculatmn of the Intraocular Flmd Bnt ~ Ophth 16 321 (1932)

59 KINSEV, V E A Untried Concept of Aqueous Humour Dynamms alnd the Maintenance of Intraocular Pressure A M A Arch Ophth 44 215 (1950)

60 L~a,~COFF, H A, ELLm, C H, D~.Vo~., A G, & DE BE~n, E The Elffect of Succmylcho- hne on Intraocular Pressure Am J Ophth r 501 (1955)

61 MAcro, F J Acetazolam~de and the Venous Pressure of the Eye A M A Arch Ophth 63 953 (1960)

62 BnEININ, G M & MOLDAVEn, ] Electromyography of the Human Extraocular Muscles A M A Arch Ophth 54 200 (1955)

63 BnEINr~, G M The Positron of Rest During Anesthesm and Sleep Electromyographm Observahons A M A Arch Ophth 57 323 (1957)

64 MAnC, E , ~AMPOLSXY, A, & TAML~n, E Elements of Human Extraocular Electro- myography A M A Arch Ophth 61 258(1959)

65 SOnEL, A M Hexafluorenmm, Succmylcholme and Intraocular Tensmn Anaesth & Analg 41 399 (1962)

66 WA~L~, A Chmcal and Experimented Studms on Effects of Sluccmylchohne Acta Anaesth Scandmav Supplement v (Ju~e, 19160)

67 WnV.TL~D, A & WAHL:N, A The Effect of Succmylchohne on the Orbital Musculature of the Cat Acta Anaesth Scandmav 3, 101 (1959)

A CAtlBALlr,O SUCCINYLCHOrffNTE AND ACIITAZOLA1VLIDE

68 CAMr~ON, A & BtraN, R A Hexamethonmm and Glaucoma Bnt J Ophth 86 482 (1952)

69 CLANK, W B & DUCaAr~, J w The Use of Dlbenamlme m the Treatment of Acute Congestwe Glaucoma Am ] Ophth 34 535 (1951)

70 ColaD~O, V F & Am~owwooD, J G Mylaxen Prehmmary Chmcal Evaluation of a New Agent for Neuromuscular Blockade Anaesth & An,I]lg 34 112 (1955)

71 FAJAI~o, R V, H~mTON, R, & LEOPOLD, I H The! Effect of Hydrochlorothlazxde (Esldrex) on Intraocular Pressure an Man Am J Ophth 49 1321 (1960)

72 FOLDES, F F , MOLLOY, R E , ZSmMOND, E K, & ZW~UaT, j A Hexafluorenlum Its Antachohnesterase and Neuromuscular Actwlty ] Pharmacol Exper Therap 129 400 ( 1960 )

73 FOLDES, F F , HrLLMFaL N R, MOLLOY, R E , & Molll~'c~, A P Potentiation of the Neuromuscular Effect of Succmylcholme by Hexafluc!renmm Anesthesiology 21 50 (1960)

74 GALII~r, M A, ArZAWA, F , & McLEAN, J M Intravenous Urea m the Treatment of Acute Angle-Closure Glaucoma Am J Ophth 50 37911960)

75 GALV'~, M A , McIvoa, J W , & MAClaUDEa, G B Infl~ence of Poslhon m Intraoc,ular Pressure Am J Ophth 55 720 (1963)

76 GARTNXR, S Methods of Inducing Anesthesm and I-]lypotony for Cataract Surgery A M A Arch Ophth 61 50 (1959)

77 AemUGA, H DmmoxmOphthahnology Arch Soc Ophth Hlspano-am 15 374 (1955) 78 B~aTOLOZZL R & GArtc~-ALIx, C Dmmox m the Treatl]ment of Glaucoma Prehrmnary

Commumcatlon Arch Soc Ophth Hlspano-am 15 381 (1955) 79 BECrCE'a, B Decrease m Intraocular Pressure m Man by a Carbome Anhydrase Inhab,tor,

Dmmox Am J Ophth 37 13 (1954) 80 BEAKER, B The Mechamsm of the Fall m Intraocular ]l'ressure by the Carbomc Anhy-

drase Inhlbator, Dmmox . ~ J Ophth 39 177 (1955) 81 GnANT, W M & Tr~OTTER, R R Dmmox (Acetazolleamlde) m the Treatment of

Glaucoma A M A Arch Ophth 5/ 335(1954) 82 Gr~EEN, H , Ca.ePEa, Bocr~a, C A, & LEOPOLD, I H The Effect of Dmmox on the

Carbomc Anhydrase Achwty of the Anterior Urea of the Rabbit Eye A M A Arch Ophth 52 758 (1954)

83 GRF~N, H , BOCHEa, C A, CALNAN, A F , & LEOPOLD, ] H Carbomc Anhydrase and the Maintenance of Intra Ocular Tension A M A Arch Ophth 53 463 (1955)

84 KRONFmLD, P C & Fm~EM.AN, H M The Effect of Acetazolamlde on the Response to Anterior Chamber Puncture m Man Am J Ophth 60 ] 141 t 1960)

85 LANGHA~, M E Specificity and Comparatlve-Achvlty of the Carbomc Anhydrase Inhlbltors Neptazane and Dlaraox on Ammal and HUman Eyes Bnt J Ophth 42 577 (1958)

86 MAcro, F J & G a ~ s , P A The Effects of Succmylchohne on the Extraocular Statute Muscles and on the Intraocular Pressure Am J Ophth j~4 221 (1957)

87 SE~s, M L Intraocular Pressure of Unanesthetmed Hen Lack of Response to Aceta- zolamlde A M A Arch Ophth 63 219. (1960)

88 Outflow Resistance o f the Rabb~t Eye Techmquet and Effects of Acetazolam~de A M A Arch Ophth 64 823 (1960)

89 W ~ s ~ - D , P The Effect of Carbomc Anhydrase Inhibitor on Intraocular Pressure w~th Observataons on the Pharmacology of Acetazolamade ~n the Rabb~t Acta Pharmacol et Toracol 16 171 (1959)

90 M~r.~aD, J F & Sc~-mm, H G Transient Myopm afller Acetazolam~de A M A Arch Ophth 63 315 (1960)

91 ALFA~O, J E & CLa~,xT, J Injection of Hyaluromdase into the Anterior Chamber of the ~abb~t Eye Am J Ophth 39 198 (1955)

92 Aas r~ r~s , M & Homso~, H The Effect of Lobotomy and Electroshock on Iatra- ocular Pressure Am ] Ophth 35 3 (1952)

93 B~.c~xa, B & FmmD~NWALD, J S Chmcal Aqueous Outflow A M A Arch Ophth 50 557 (1953)

94 CASTmLO, J C & D~ B~ER, E ~ Neuromuscular Blocking Action of Succmyleh01me (D~acety]cho]me) J Pharmaco~ & E• Therap 99 458 (1950)

95 Cor~r~oN, H A General Anesthesia m �9 Surgery Bnt J Ophth 86 611

498 CANADIAN ANAESTHETISTS' SOCIETY JOURNAL

96 DAVSON, H & SPAZIANI, E The F~te of Substances Injected Into the Anterior Chamber of the Eye J Physlol 151 202 (1960)

97 D~. B~.ma, E J & CASTI~.LO, J C Synthehc Diugs Influencing Neuromuscular Actwlty An New York Acad Sea 54 362 ( t951 ~,

98 DE ROETTH, A JR Ophthalmm Pharmacology and Toxmology A M A Arch Ophth 64 292 (1960)

99 DE R o E ~ , A JR Ophthalmm Pharmacology and Toxicology A M A Arch Ophth 66 277 (1961)

100 Dtrm~.-ELDEn, S W The Phasm Variations In the Ocular Tension m Prmaary Glaucoma Am J Ophth 35 1 (1952)

101 ELT.m, C H , WNuc~r, A L , FANELLI, R V, & DE BEF.a, E Comparative Pharmaco- logmal Study of the Mono and Dichohhe E,,ters of Succmm Acid J Pharmacol 109 83 (1953)

I02 FOLWS, F F , McNALL, P G, & BonRI~.C,O-HINoJOSA, J M Succmylchohne A New Approach to Muscular Relaxatmn m Anesthesiology New England J Med 247 596 (1952)

103 LUND, P C Clmmal Evaluahon os SuCcmylchohne Chloride as a Muscle Relaxant in Anesthesm Am J Surg 86 312 (1953)

104 Mno~, A J Electromyogram of the Extraocular Muscles of the Rabblt m S1tu A M A Arch Ophth 52 21~ (1954)

105 M A ~ , R W , SCHUMAN, C R, & H&BI~ISON , S I Influences of Curare and Eserine on Ocular Tensmn following ElectroshocIk Am J Ophth 37 859 (1954)

106 PArON, W D M & Z~MIS, E Actaon,J and Chmcal Assessment oJ ~ Drugs which Pro- duce Neuromuscular Block Lancet 2 568 (1950)

107 PAUL, S D & LEOPOLD, I H The Effect of Chlorpromazme on Intraocular Pressure m Expermaental Ammals Am J Ophth 42 107(1956)

108 GONZkLEZ, C Topmal Fludrocorhsone (9-AIpha-Fluorohydrocorhsone) m Ophthal- mology Arn J Ophth 49 619 (1960)

109 GRANT, W M Tonography in Chxomc Glaucoma New York ] Med 56 193 (1956) 110 GraFFITI L H R & JOm~STON, G E The Use of Curare m General Anaesthesm

Anesthesmlogy 3 418 (1942) 111 HOWLArCD, W S~ BoY,~a% C P, & WANG, I~ C The Use of a Steroad (Vmdrd) as

an Anesthetic Agent Anesthesmlogy 17 I (1956) 112 HtrnTER, A R A Study of a New Relaxant Dlug Anaesthesm 7 141 (1952) 113 IfmNNEDV, R E Medmal Treatment of Chrome Glaucoma New York J Med 56 201

( 1956 ) 114 KmBY, D B Use of Curare m Cataract Surgery AM A Arch Ophth 43 678

( 1950 ) 115 KORNBLUETH, W, JAMPOLSKY, A, TA1VI.hElq~, E, & MARG, E Contraction of the

Oculorotatory Muscles and IntraocuLir Pressure A Tonographac and Electromyo- graphic Study of the Effect of EdrophDnmm Chloride (Tensdon) and Succmylchohne (Anectine) on the Intraocular Pressure Am I Ophth 49 1381 (1960)

116 LAr~DMESS~., C M A Study of the Bronchoconstrmtor and Hypotenslve Actmn of Curanzmg Agents Anesthesmlogy 8 50,6 (1947)

117 LINNER, E & PmloT, E Cervical Sympathetm Ganghonectomy and Aqueous Flow A M A Arch Ophth 54 831(1955)

118 SCHMERL, E & STmNBF_~C, B Separatmn of Dieneephahc Centers Concerned with Pupfllary Motd~ty and Ocular Tension Am J Ophth 33 1379 (1950)

119 SEA~S, M L & BkakNx, E Outflow Resistance and Adrenergm Mechamsms A M A Arch Ophth 64 839 (1960)

120 STONE, H H & PmIOT, E Effect o~ a Barbataarate and Paraldehyde on Aqueous Humour Dynamms an Rabbits A M A Arch Ophth 54 834 (1955)

121 TxN~r~, G S & SCH~.m, H G MechamSm o~ the Myotae-Resistant Pupil with Increased Intraocular Pressure A M A Arch Ophth 5 0 572(1953)

122 WmTaAND, P & MArtEN, T H The Effect of Carbomc Anhydrase Inl~bitmn on Intraocular Pressure of Rabbits with Different Blood COe eqmhbrm Am J Ophth 50 (19 0)

123 WNUC~, A L , NORTON, S, & ELLIS, C H Controlled Paralyses,of Skeletal l~iuscle Anesthesmlogy 14 367 (1953)