Superiority of spacer / mask topical anaesthetic compared with conventional spray and gargle method for fibreoptic bronchoscopy

OB JEC TIVE: To com pare the safety and ef fi cacy of a new spaceroral na sal mask de vice with those of the stan dard nee dle noz zle spray method for the de liv ery of aero sol ized lido caine to the up per air way for prebronchoscopic an aes the sia in a ter ti ary care hos pi tal. DE SIGN: Singleblind ran dom ized con trol trial. SET TING: Uni ver sity af fili ated ter ti ary care hos pi tal, am bu la tory care bron cho scopy unit. SUB JECTS: Thirty con secu tive con sent ing pa tients re ferred for fi bre op tic bron cho scopy for vari ous in di ca tions. IN TER VEN TION: Thirty ran dom ized sub jects re ceived 150 mg of topi cal 1% aero sol ized lido caine via stan dard long nee dle nosed ap pli ca tor (group A) or via a new oral/ na sal mask with spacer de vice (group B). Bron cho scopists, blinded as to the pre pro ce dure topi cal an aes thetic method used, gave ad di tional topi cal lido caine at their dis cre tion. MEAS URE MENTS: The study nurse re corded the to tal dose of lido caine (mg), tim ing of the pro ce dure (s), cough fre quency ex pressed as coughs per minute (c/min), vi tal signs, time for re turn of gag re flex and pa tients’ sub jec tive com ments. RE SULTS: Fif teen pa tients were ran dom ized to each group. The lido caine dose re quired for in ser tion through the vo cal cords (mean ± SD) was 282.6±66.3 mg in group A and 203.3±70.6 mg in group B (P<0.005). To tal lido caine dose re quired for the pro ce dure was 330.6±70.2 mg in group A and 256.6±75 mg in group B (P<0.01). The mean time for pas sage of the bron cho scope from mouth en try to through the vo cal cords was 82.7±54.5 s in group A and 110.5±64.4 s in group B (P>0.1). The mean to tal time for the pro ce dure was 699.7±377.5 s in group A and 697.2±409.1 s in group B (not sig nifi cant). The mean cough fre quency was 8.2±6.1 c/min in group A and 7.0±5.7 c/min in group B (not sig nifi cant). There were no sta tis ti cally sig nifi cant dif fer ences in heart rate, in re turn of gag re flex time or in com pli ca tion rate be tween the two groups. CON CLU SIONS: A sta tis ti cally sig nifi cant re duc tion in the dose of lido caine is re quired to achieve equiva lent topi cal an aes thetic for bron cho scopy with a new mask and spacer de vice com pared with a more con ven tional method. Since no other vari ables re lated to the pro ce dure showed a sig nifi cant dif fer ence, the new method ap pears to be su pe rior to the pre vi ous method. (Pour rés umé voir page 177)

F i bre op tic bron cho scopy is in di cated in nu mer ous clini cal sce nar ios and pro vides a vi tal di ag nos tic tool in cur rent res pi ra tory medi cine.Un for tu nately, consid er able pa tient dis com fort is as so ci ated with this proce dure.Many pa tients ob ject to the un pleas ant taste of lido caine, and to cough ing and gag ging dur ing the gargling and spray ing of the oro pha rynx.This stan dard spray method of ten de lays the start ing of the pro ce dure due to marked pa tient dis com fort and anxi ety.This may lead to a pro longed, poorly tol er ated pro ce dure with subop ti mal sam ple col lec tion.Fur ther more, pa tients who have suf fered through one pro ce dure are re luc tant to re peat the pro ce dure when nec es sary.
Nu mer ous authors have evalu ated vari ous techniques for an aes the tiz ing the up per air way with aerosol ized or nebu lized lido caine (1).Ad min istra tion of lido caine by nebu lizer has been ad vo cated, but this method re quires large doses of medi ca tion and has not been very ef fi cient or ef fec tive (2)(3)(4).Clark and Pond (5) have re cently de scribed at omi za tion of the drug.
Aero sol ther apy with beta-agonists us ing a me tered dose in haler (MDI) (es pe cially with hold ing cham ber) is 2.5 to six times as ef fi cient as con tinu ous nebu li za tion for bron cho di la tion in asth mat ics (6,7).Other in ves ti gators have de vel oped new meth ods of ef fi ciently 'ta rgeting' the res pi ra tory tract (eg, spacer de vices) (8).
This study com pared the dose of lido caine, the time re quired and the sub ject tol er ance for a new spacer/mask de vice ver sus a con ven tional spray ap pli -ca tor de vice in the de liv ery of aero sol ized lido caine to the oro pha rynx be fore bron cho scopy.

PATIENTS AND METHODS
Sub jects: Thirty con secu tive sub jects were en tered into the study.Ex cluded sub jects had con tra in di ca tions to one or more pro to col medi ca tions (ie, at ro pine, mi dazo lam and lido caine).All sub jects were in formed of all pro ce dures and signed ap pro pri ate con sent forms.The Hos pi tal Eth ics Com mit tee for Hu man Re search approved the pro to col.Pre medi ca tion: Sub jects re ceived at ro pine (0.4 to 0.6 mg/s) 30 mins be fore the pro ce dure.Af ter sub jects consented to par tici pate in the study, all pa tients re ceived mi da zo lam (5 mg in tra mus cu larly or 2 mg in tra venously) just be fore start ing the pro ce dure.

Ran domi za tion and blind ing:
A nurse re search as sistant us ing a ran dom num bers ta ble as signed sub jects to the stan dard spray method (group A) or to the spacer/mask method (group B).Sub jects were then given the topi cal an aes thetic by the nurse be fore the phy si cian en tered the en do scopy suite.The bron choscopist was there fore blinded to the an aes thetic technique used.Pro ce dure: Sub jects re ceived 150 mg (15 ac tua tions) of 1% lido caine (Xy lo caine; As tra) (10 mg/mL) di rected onto the phar ynx via the stan dard spray de vice or the new spacer/ mask de vice.The stan dard method used a stan dard aero sol MDI with a long nosed metal ap pli cator (Fig ure 1) to spray the pos te rior phar ynx and the vo - If the pa tient started to cough dur ing the ap pli ca tion the nurse would wait un til cough ing ceased be fore giv ing the next ac tua tion.Sub jects who re ceived lido caine us ing the new method placed the spacer/mask de vice over their mouth and nose (Fig ure 2).The oral na sal mask al lowed the pa tients to use the open mouth tech nique for breath ing in the medi ca tion.
With each ac tua tion of the de vice, sub jects were directed to take rapid deep breaths through their widely open mouth to to tal lung ca pac ity to achieve rela tively high in spi ra tory flow rates (ap proxi mately 60 L/min).They were moni tored dur ing the pro ce dure to en sure that they did not in hale via the nose.With the new technique, the lido caine MDI was ac tu ated at 10 s in ter vals, thus de liv er ing the 150 mg of lido caine over ap proximately 3 mins.The bron cho scope was in tro duced through a hollow bite block be tween the teeth and passed through the vo cal cords.The bron cho scopist used ad di tional 4% lido caine (40 mg/mL), in stilled di rectly onto the vocal cords through the bron cho scope, as needed, to con trol cough and la ryn go spasm.Past the vo cal cords the pro ce dure was car ried out in the usual man ner with in stil la tion of 1% topi cal lido caine so lu tion ap plied through the bron cho scope, 1 mL at a time, as re quired to mini mize cough.The study nurse re corded the to tal dose of lido caine re quired to al low the bron cho scope to be passed through the vo cal cords, as well as the to tal dose for the whole pro ce dure.Out comes: The pri mary out come meas ure was the total lido caine dose re quired (mg) to com plete the pro cedure.Sec on dary out come meas ures in cluded the lido caine dose re quired to pass the bron cho scope through the vo cal cords (mg), the time from in tro duc tion of the bron cho scope into the mouth to the bron choscope pas sage through the vo cal cords (s), to tal pro cedure time (s) and cough fre quency (c/min).The number of coughs and vari ous times were re corded by the nurse re search as sis tant us ing a man ual coun ter and stop watch.
Other out comes evalu ated dur ing the pro ce dure were maxi mum change in heart rate and com pli ca tions (bleed ing, pneu motho rax, etc).Pa tients were also asked for any gen eral com ments re gard ing any discom fort from the pro ce dure.Data analy sis: The arith metic means of the to tal dose 178 Can Respir J Vol 3 No 3 May/June 1996

Balk is soon et al
Fig ure 1) Stan dard method uses an aero sol me tered dose in haler with a long nosed metal ap pli ca tor Fig ure 2) New method places the spacer/mask de vice over the mouth and nose   of lido caine topi cal an aes thetic re quired, the mean time to pass through the vo cal cords, mean cough fre quency and mean to tal number of coughs were com pared between the two groups us ing un paired t test analy sis.

Sub ject char ac ter is tics:
There were 15 sub jects random ized to each group.There were no sig nifi cant differ ences with re gard to sex, age or smok ing his tory (Ta ble 1).No sig nifi cant dif fer ences were de tected between groups with re spect to in di ca tions for bron choscopy (Ta ble 2) or to the type of pro ce dures per formed (Ta ble 3).Lido caine dose: The lido caine dose re quired for in sertion of the bron cho scope through the vo cal cords (mean ± SD) was 282.7±66.4mg in group A and 203.3±70.7 mg in group B (P<0.005).To tal lido caine dose re quired for the pro ce dure was 330.7±70.2mg in group A and 256.7±75.7 mg in group B (P<0.01).Length of time for pro ce dure: The mean du ra tion from the time the bron cho scope passed the lips un til inser tion through the vo cal cords was 82.7±54.5 s in group A and 110.5±64.4s in group B (P>0.1).The to tal time for the pro ce dure was 699.7±377.5 s in group A and 697.3±409.1 s in group B (P>0.1) (Ta ble 4).Other pa rame ters: Cough fre quency was 8.2±6.2 c/min in group A and 7.0±5.7 c/min in group B (P>0.1).There were no sta tis ti cally sig nifi cant dif fer ences in changes in heart rate, in re turn of gag re flex or in compli ca tion rate be tween the two groups.Sub jec tive comments about taste and tol er abil ity of an aes thetic and bron cho scopy pro ce dures were simi lar in the two groups.

DISCUSSION
Topi cal an aes the sia re mains a fairly cum ber some and time con sum ing tech nique which, us ing our standard spray pro ce dure, in volves ei ther ap ply ing lidocaine gel to the na sal air way for per na sal in tro duc tion and/or gar gling 2 mL of un pleas ant tast ing 4% lido caine so lu tion in ap proxi mately 8 mL of wa ter for per oral inser tion of the bron cho scope.This is fol lowed by blindly spray ing a 1% so lu tion onto the phar ynx, epi glot tis and vo cal cords and then giv ing ad di tional 4% lido caine solu tion 1 mL at a time di rectly onto the cords un der di rect vi sion through the bron cho scope.
Topi cal an aes the sia above and onto the cords usually re quires the ad mini stra tion of up to 300 mg of lidocaine, pro vided in 40 mg ali quots (40 mg/mL).On go ing topi cal an aes the sia of the lower res pi ra tory tract gen erally re quires an ad di tional 100 to 300 mg of 1% lidocaine, the larger doses for pro longed pro ce dures such as fluoro scopi cally guided trans bron chial bi opsy (to tal maxi mum lido caine dose 400 mg over 20 to 30 mins).Gar gling with and spray ing un pleas ant tast ing lido caine onto the oro pha rynx and up per air way causes many pa tients to gag and cough, which de lays the start of the pro ce dure and cre ates sig nifi cant pa tient anxi ety.This anxi ety may ex ac er bate cough ing and gag ging, lead ing to a pro longed poorly tol er ated pro ce dure with subop timal sam ple col lec tion.Pa tients who have suf fered through one pro ce dure are re luc tant to re peat the proce dure when needed.
The cur rent proj ect tested a unique spacer/mask deliv ery sys tem to study pa tient ac cep tance, re duc tion of bron cho scope in ser tion time, to tal bron cho scopy time and an aes thetic dose re quire ments com pared with a tech nique cur rently used by many bron cho scopists.
The new method at tempted to anaes the tize the airway from the tongue to the pe riph ery by tak ing ad vantage of dis per sion of the drop let aero sol pro duced by these can is ters via the spacer/mask de vice.The larger drop lets in the aero sol spray (which con tains par ti cles of many sizes from ap proxi mately 30 mm down to 1 mm) are more likely to be de pos ited in the up per res pira tory tract and cen tral air ways be cause of high in spi ratory flow rates that fa vour im pac tion, while the smaller par ti cles (less than 5 mm) are likely to be car ried to more pe riph eral air ways (9).
Thus the spacer/mask method should pro vide topical an aes the sia to the whole res pi ra tory tract, from the mouth to the pe riph eral air ways, de pos it ing the ma jor ity of the dose in more proxi mal air ways at the level of the gag and cough re cep tors.These re cep tors are lo cated mainly in the phar ynx and up per res pi ra tory tract around the vo cal cords and in the cen tral air ways of the lower res pi ra tory tract (10).It was pos tu lated that this spacer dis persed aero sol would be more evenly dis tributed to these re cep tors than would be the case with the noz zle spray method, thus pro vid ing ef fec tive topi cal an aes the sia with a smaller to tal dose.Mini miz ing to tal topi cal lido caine dose is de sir able be cause there are re ported sys temic side ef fects (11)(12)(13).
This study con firms that the spacer/mask de vice provides equiva lent symp to matic bene fit to the spray method with a 25% de crease in the to tal dose of lidocaine.No sig nifi cant dif fer ences were ob served between the two meth ods in terms of time to pass the en do scope through the cords, to tal time of the pro ce -  dure, cough fre quency or change in heart rate.The dose re duc tion trans lates into cost sav ings.The safety and ease of pre medi ca tion with lido caine us ing the new spacer/ mask method al lows en do scopy nurses to read ily per form this pro ce dure, thus sav ing phy si cian time.
We did not in clude data re gard ing the time taken to ad min is ter the 15 ac tua tions of 1% lido caine ei ther via the stan dard or new method.Typi cally it took longer to use the stan dard method be cause the nurse would often have to wait for the pa tient to stop cough ing between ac tua tions.The spacer mask method caused very lit tle cough re sponse dur ing the ac tua tions.Because it was not pos si ble to do this part of the study in a blinded fash ion, we felt that there was sig nifi cant po tential for bias by the study nurse in terms of de cid ing when to re sume giv ing the lido caine us ing the stan dard method.
The nurse who gave the pre medi ca tion an aes thetic also counted coughs us ing a man ual coun ter.The fact that the nurse was not blinded to the type of pre medi cation ad min is tered could theo reti cally lead to bi ased count ing of coughs.No dif fer ence was noted be tween the two groups with re spect to cough fre quency, which could be in ter preted to mean that there was no true differ ence be tween the two groups or that the nurses under-counted or over-counted coughs in one or the other group.Cough fre quency was one of many measures re corded to com pare pa tient tol er ance of the proce dure be tween the two treat ment groups.Other meas ures such as change in heart rate, time to complete the pro ce dure and sub jec tive com ments of patients in di cate that pa tient tol er ance was com pa ra ble be tween the two groups.
We did not meas ure se rum lido caine lev els in this study.Pre vi ous stud ies (4,13) have dem on strated that sys temic se rum lev els of lido caine are well be low the rec om mended thera peu tic range of 2 to 6 mg/mL when the lido caine is de liv ered by ul tra sonic nebu lizer plus di rect in stil la tion of lido caine onto the mu cosa of the up per and lower air ways.To tal doses of lido caine de liv ered to the air ways were in the range of 450 to 540 mg in one study (4) and over 1600 mg in an other study (13).These val ues are sig nifi cantly higher than the maxi mum lido caine doses used in our study (ap proximately 400 mg).It is un likely that the dose of drug de livered to the tra cheo bron chial tree is higher with the spacer de vice be cause a sig nifi cant por tion of the dose is cap tured in the spacer de vice it self.We pro pose that the spacer de vice tech nique re sults in de liv ery of a more uni form dis tri bu tion of the medi ca tion to the airways.Fur ther more, nei ther group dem on strated evidence of lido caine tox ic ity, par ticu larly cen tral nerv ous sys tem ex ci ta tion or de pres sion, or car dio vas cu lar com pro mise such as bra dy car dia or hy poten sion.
Al though the pa tients' sub jec tive com ments re garding the ac tual an aes thetic pro ce dure are the 'sof test data', these com ments are po ten tially the most use ful clini cal in for ma tion as to whether the spacer/mask method of fers any per ceived symp to matic bene fit to the pa tient.Not sur pris ingly, in this study there is lit tle to dis tin guish the na ture of these com ments be tween the two groups be cause pa tients were an aes the tized with one method or the other and thus could not com pare them.

CONCLUSIONS
This study dem on strated that ini tial topi cal an aesthe sia de liv ered as a widely dis persed aero sol from a spacer/mask de vice re sulted in the need for a re duced to tal dose of lido caine to achieve equiva lent cough control com pared with a highly fo cused drop let spray directed against the phar ynx.This sug gests that the more dis persed aero sol spray is able to anaes the tize the pos te rior phar ynx and fau ces bet ter than the older method.Since the pri mary out come vari able was the ad di tional lo cal an aes thetic nec es sary to achieve op timum cough con trol it is not sur pris ing that no dif ferences could be dem on strated in any of the other out come meas ures.

bron cho scopic an aes the sia
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