KISEP Otology Korean J Otolaryngol 6;49:887-91 장병들의사격에의한소음성난청 공군제 전투비행단항공의무대대 문인석 Noise Induced Hearing Loss Caused by Gunshot in Military Service In Seok Moon, MD R.O.K.A.F. th Fighter Wing Aeromedical Squadron, Seosan, Korea ABSTRACT Background and Objectives:Noise induced hearing loss (NIHL) is a preventive disease and yet the effective treatment modality has not been established. Acute acoustic traumas caused by an exposure to gunshot noise are common in young Korean males in the military service. Considering the significant lack of awareness on this serious issue as well as the absence of proper protection gears, an in-depth analysis is desperately needed. Subjects and Method:3,65 soldiers performed a regular gunshot exercise without any hearing protective measures. Out of 3,65 soldiers, 8 patients with hearing impairment after the regular gunfire visited aeromedical squadron. They were all right-handed males:7 had been tested with K-2 rifle and 1 had been tested with K-5 revolver. History taking, physical examination, pure-tone audiometry, and impedence audiometry were performed. In the next round of gunshot practice, all soldiers performed gunfire with unilateral hearing protection. Results:The average outcome of postexposure air conduction thresholds were 6.5 db in the right ear and 33.1 db in left ear. After medical treatment, hearing impairment was much improved;however, tinnitus was not diminished. In the next round of gunshot practice, the supplement of unilateral earplug protection proved its effectiveness on acoustic trauma caused by gunfire noise. Conclusion:Asymmetry of hearing loss was related to head position during gunfire. Unilateral hearing protection device was enough to protect hearing from acoustic trauma caused by gunshot. At the same time, it can effectively prevent a potential firearm accident that can be caused by trainees mishearing the instruction of firearm instructor if both earplugs are worn. Thus, providing unilateral earplug protection against acoustic trauma must be taken into serious consideration. (Korean J Otolaryngol 6;49:887-91) KEY WORDS:Gunshot Noise induced hearing loss Ear protective devices. 서론 소음성난청은효과적인치료가없으나예방가능한질환이다. 1) 따라서청력보호구등을사용하여사전에예방하는것이중요하고조기에발견하여적절한조치를하는것이필요하다. 전인구의약 1.7% 가소음성난청에의한장애를가지고있는것으로알려져있으며 2) 소음성난청의가장흔한원인은공장소음이고 3) 다음으로총기류에의한음향외상 (acoustic trauma) 이다. 4) 총기류에의한음향외상은소총의경우전형적으로두부음영효과 (head shadow effect) 에의해편측성또는오른손잡이에서좌측귀의청 력손실이큰비대칭적청력손실을초래한다. 5) 특히우리나라에서는젊은남성대부분이병역중총기소음에노출이되고있어이에대한예방이절실히요구된다. 그러나현재귀마개와같은간단한개인청력보호구착용및예방교육활동이미흡한실정이며사격에의한장병들의청력손실에대한연구도한정되어있다. 본연구에서는사격후돌발성청력손실이생긴장병들의청력손실을분석하고개인청력보호구착용에의한청력손실예방효과를알아보고자한다. 대상및방법 논문접수일 :5 년 9 월 21 일 / 심사완료일 :6 년 6 월 7 일교신저자 : 문인석, 356-828 충남서산시해미면석포리사서함 384-21 공군제 전투비행단항공의무대대전화 :(41) 689-1774 전송 :(41) 689-39 E-mail:andrewmoon@empal.com 공군제 전투비행단에서 4년 4월 12일부터 5월 4 일까지개인청력보호장구의착용없이실사격을실시한약 3,65 명의현역장병중청력이상및이명을호소하여의무대로내원한 8명을대상으로과거병력, 과거소음 887
일측성청력보호구착용의사격에의한청력손실예방효과 에의노출력, 개인청력보호장구착용여부등을조사하고이학적검사, 순음청력검사, 임피던스청력검사등을실시하였다. 순음청력검사 (Granson-Stadler Inc. NH 355-56) 는.25,.5, 1., 2., 3., 4., 8. khz에서혼합법을사용하여측정하였다. 모든결과는 1995년미국이비인후과학회기준 (AAO-NHS standard, 1995) 을따라서보고하였으며소음성난청의특성상고주파영역에대해추가분석하였다. 8명의환자중 7명은내원다음날부터경구용스테로이드제제 (Prednisolone 6 mg/day, 유한양행 ) 로 5일간치료하였으며그후 5일간에걸쳐감량하였다. 1 명은발병약 1개월후내원하여 ginko biloba(ginexin-f, 8 mg/day, SK제약 ) 로 2개월간치료하였다. 대상자들은내원후 2주간 3일간격으로청력검사를실시하였고그후 4개월간 1개월간격으로 4년 1월말까지청력을측정하였다. 4년 9월 13일부터 1월 19일까지공군제OO전투비행단현역장병들을대상으로 ( 약 3,65명 ) 실시된정기실사격에서는사격전소음성난청에대한교육후 29 db의음향차폐효과를가진개인청력보호장구 (3M 11 foam type earplug) 를모든장병들에게지급하여오른손잡이에서좌측귀에, 왼손잡이에서우측귀에일측만착용하도록한후사격을실시하게하였다. 사격직후사격을실시한장병들에게청력손실유무및이명발생여부를조사하였으며또한청력손실로인한의무대내원수진율을조사하였다. 보호장구착용없이사격한후의청력손실정도에대해서는 Wilcoxon signed rank test 를, 귀마개사용후청력보호효과에대하여 chi-square test를사용하여통계학적분석을하였고유의확률 (p-value) 이.5 이하인경우를통계학적으로유의하다고판단하였다. 결과 조사대상은 8명으로 세부터 세까지였으며평균연령은 22.1 세였다. 모두남자였고오른손잡이였다. 과거력상특이병력은없었고대상자 8명중 1명은약 1년전실사격시좌측귀청력이상증상이있었으나당시는발병 1주만에자연회복되었다. 이학적검사상모두특이소견은관찰되지않았고임피던스청력검사상고막운동성은대상자모두양측 A type 이었다. 대상자들은모두청력보호장구착용없이사격을실시하였으며대상자중 7명은 K-2 소총 (5.56 mm, 대우정밀 ) 으로 발실사격을실시하였고 1명은 K- 5 권총 (9. mm, 대우정밀 ) 으로 1발의실사격을실시하였다. 내원당시 8명모두좌측귀의청력감소와이명을호소하였다. 증상은모두사격직후부터발생하였고 K-2 소총사격을실시한 7명은증상발현후 1일째부터 1일째에의무대로내원하였다. K-5 권총사격을실시한대상자는 1년전 K-2 소총사격을실시한뒤청력이상증상발생후자연회복된과거력이있었고증상발생후약 1개월째내원하였다 (Table 1). 대상자중일부만이증상발현전청력검사를실시하였기때문에사격전청력수준과사격후청력수준의직접비교는한계가있어장병들의사격전청력이정상이었다는가정하에좌 우청력을비교하였다. 소음노출후의무대내원당일청력검사결과청력역치평균은우측귀 6.5±1.7 db, 좌측귀 33.31±8.94 db로양측귀의청력역치평균값사이에통계학적으로유의한차이가있었다 (p=.). 청력역치의평균값을주파수별로보면청력손실의형태는.25,.5, 1. khz 의저주파수에비해 3., 4., 8. khz의고주파수에서현저하였다 (Fig. 1). Table 1. The characteristics of patients with hearing impairment due to gunfire noise Patient Age Symptom Yoo Hearing loss Baek 21 Hearing loss Kim 21 Hearing loss Jin 21 Hearing loss Kim Hearing loss Maeng 21 Hearing loss Yang 22 Hearing loss Kim 21 Hearing loss Postexposure hearing Right 7.5 db Left 39.2 db Right 3.3 db Left.6 db Right 6.7 db Left 35. db Right 8.3 db Left 27.8 db Right 5.5 db Left 19.1 db Right 5.7 db Left 24.2 db Right 8.5 db Left 45.6 db Right 6.5 db Left 35. db Start of treatment Treatment regimen Posttreatment hearing 4th day Oral steroid Right 6.7 db Left 1.8 db 1th day Oral steroid Right 4.1 db Left 28. db 1st day Oral steroid Right 5.8 db Left 18.3 db 1st day Oral steroid Right 7.5 db Left 11.7 db 31st day Ginko bloba Right 5.5 db Left 14. db 1st day Oral steroid Right 6.7 db Left 12.1 db 1st day Oral steroid Right 7.5 db Left 24.8 db 1st day Oral steroid Right 6.5 db Left 17.3 db Remained symptom Time for recovery 28 days days 72 days 4 days days 13 days 35 days 12 days 888 Korean J Otolaryngol 6;49:887-91
문인석 Hearing level in decibels (db, ASA 1995) 1 5 6 7 8 9 1 11 125 25 5 75 1 15 6 8 Fig. 1. Average outcome of postexposure air conduction threshold in 8 patients who performed regular gunfire exercise without hearing protection. The air conduction threshold was measured in first day of their visiting to aeromedical squadron. Each marks on audiogram scale were average threshold of 8 patients at each frequency. High frequency hearing loss was noted in left ear. 1 5 6 7 8 9 1 11 최종청력검사결과우측귀 6.29±1.13 db, 좌측귀 17.13± 6.36 db의평균청력역치를보여 (Fig. 2), 처음내원당시의좌측귀청력에비하여치료후좌측귀청력수준의향상이있었다 (p=.1). 주관적인증상에있어서도청력손실은부분또는완전회복되었으나이명증상은 8명모두별다른호전없이남아있는상태였다. 4년 9월 13일부터 1월 19일까지정기사격이실시되었으며사격전소음성난청에대한교육후 29 db의음향차폐효과를가진개인청력보호장구 (3M 11 foam type earplug) 를전장병에게지급하여오른손잡이에서좌측귀에, 왼손잡이에서우측귀에착용한후사격을실시하게하였다. 사격직후사격을실시한장병을대상으로청력손실여부에대해서조사를실시하였고의무대내원수진율을조사하였다. 귀마개착용후실시한사격에서는청력손실, 이명등의증상이발현된경우는없었다. 보호장구착용없이사격한결과와비교해통계학적으로의의있는개인청력보호장구의청력보호효과를나타냈다 (p=.8). 125 25 5 75 1 15 6 8 고 찰 Hearing level in decibels (db, ASA 1995) 1 5 6 7 8 9 1 11 Fig. 2. Average outcome of air conduction threshold after medical treatment. 7 patients were treated with oral steroid and 1 patient was treated with ginko biloba. The hearing were measured about a month after patients hearing showed no more improvement. Each marks on audiogram scale were average threshold of 8 patients at each frequency. Left ear hearing impairment was much improved than their first visit, but still remained. 8명의대상자중 7명은증상발현후 1일째부터 1일째사이에의무대로내원하여내원다음날부터경구용스테로이드제제를사용하여치료하였으며 1명은증상발현후 1 개월째내원하여 ginko bloba만으로치료하였다. 내원후 2주간은 3일마다청력검사를실시하였으며그후 4개월간 1개월간격으로청력을측정하였다. 추적관찰기간은 3개월부터 5개월까지평균 4.3 개월이었다. 4 년 1월실시한 1 5 6 7 8 9 1 11 소음이청력에미치는영향은음향외상, 일시적역치변동 (temporary threshold shift, TTS), 영구적역치변동 (permanent threshold shift, PTS) 으로분류할수있다. 음향외상은폭발음과같은강력한음에단기간노출된후일어나며돌발성감각신경성난청으로나타난다. 순간적인폭발음에의해고막또는이소골등중이구조와난원창막, 정원창막또는 corti 기등내이구조물이기계적손상을받음으로써초래된다. 6) 현재는외유모세포와청신경섬유의기능적통합성이나세포내의생화학적변화가세포파괴및청력손실을초래한다는가설이받아들여지고있다. 6)7) 자각적이명의병태생리는명확하지않으나, 소음이나두경부외상으로인해와우내의유모세포가손상되어반복적인전기자극을중추청각경로에잘못전달함으로써소리가나는것으로잘못인지하는것으로생각된다. 8) 외국의경우총기류의소음에노출되는인구가직업군인이나사냥같은취미를가진사람에국한되는경우가많으나 4) 우리나라의경우병역의무라는특수한상황으로인해대다수의젊은남성이총기소음에노출되고있다. Lee 9) 는장병들이사용한 K-2 소총에대한사격음을근접측정하여보고하였는데 5 cm 거리에서 Kistler 압력센서 61 A를이용하여측정한결과총구소음이 161.2 db, 사격자의귀의위치에서의소음이 143.6 db이었다. 8명의대상자모두오른손잡이였고좌측귀의청력손실과 889
일측성청력보호구착용의사격에의한청력손실예방효과 Fig. 3. Top view of proper position for firing a shoulder weapon. Note angulation of head causes changing noise exposure of ear to noise source. (This figure is sourced out of Sensorineural hearing loss associated with firearms Keim s paper 1969.) Fig. 4. Top view of proper position for firing a pistol. Note lack of angulation of head causes equal noise exposure of ear to noise source. (This figure is sourced out of Sensorineural hearing loss associated with firearms Keim s paper 1969.) 이명을호소하였는데소총의경우 Fig. 3에서와같이사격에적합한자세를취하려면머리를돌려야만한다. 따라서오른손잡이의경우좌측귀가소음원이되는총구에 9도방향에가깝게놓이게되어총기소음에직접노출되는상태가되며두부음영효과에의해우측귀에는좌측귀에비해약 db정도감소된소음이전달된다. 5)9)1) 본연구에서소총으로사격을실시한 7명의경우역시이러한이유로좌측귀의청력손실과이명소견을보인것으로생각된다. 반면권총사격의경우얼굴이정면을향한자세로사격을실시하므로양측귀가소음원으로부터같은위치에놓이게되고 (Fig. 4) 총구소음에직접노출되는방향은아니며또한두부음영효과의영향을받지않는다. 5) 본연구대상자중권총사격을실시한한명의대상자에서는좌측귀와우측귀의비대칭성이나타났는데이것은대상자가약 1년전소총사격을실시했을당시의음향외상으로인한좌측귀의소음에대한취약성에기인한것으로사료된다. 8명의환자모두치료후순음청력역치의회복을보였으나이명은호전되지않았다. 음향외상후청력손실의회복여부에관해서는이견이존재하는데 Keim 5) 은총기소음에의한청력손실환자 14명을 3개월간추적관찰한결과청력의호전이없었다고보고하였으며, Oeken 11) 은 17명의폭발음에의한청력손실환자중일부에서청력의회복을보인다고보고하였다. 89 급성음향외상의응급조치로고압산소요법이혈관확장효과에의해소음에의한 PTS 를예방한다는보고가있고 12) 고용량의비타민 A, 비타민 B1, 니코틴산, 비타민 E, 성상신경절차단등의방법이효과가있다는보고는있지만비교대조군을통한연구로증명되지는못하였다. 1) Wilson 13) 은급성돌발성난청에서경구용스테로이드제제가치료에효과가있다고보고하였다. 급성돌발성난청에서 ginko biloba 의사용에대해서는논란이있으나치료효과가있다는보고들이있다. 14)15) 본연구에서는군의료여건상고압산소요법의적용이불가능했기때문에음향외상도돌발성난청을일으킬수있다는 16) 가정하에차선책으로경구용스테로이드제제와 ginko biloba 를사용하여치료하였다. 8명의대상자모두에서청력손실은완전또는부분회복을보였으나이명은호전되지않았다. 청력의회복은치료 4일째부터 72일째까지다양한시기에시작되었으며평균적으로 31일째부터회복이시작되었다. 7명의환자에서는경구용스테로이드제제를사용하여치료하였으나 1명의경우는스테로이드치료없이호전되었기때문에음향외상에의한청력손실이스테로이드제제의효과에의해회복이되었는지자연회복되었는지에대한판단은하기힘들었다. 국내보고에따르면자각적이명환자의남녀빈도는 1.5: 1로서남자에많고연령별로는활동이많은 대 ~5 대가전체의 83.6% 나되어이명환자가고령자에많을것이라는일반적예상과다르다. 17) 부위별로는일측이전체의약 3/4 이고좌측이우측보다월등히많다. 그이유는명확하지않으나사격, 두경부나귀부위의외상이우측보다좌측에많이발생하기때문이라할수있다. 17) 비록본연구의대상중모든환자에서청력의회복은완전혹은부분적으로있었으나이명은모든환자에서지속되었다. 자각적이명이젊은연령에서좌측에월등히많은것이사격에의한음향외상과관계가많다는보고와부합한다. 이명의치료가쉽지않으며자연회복되는경우에도회복기간까지의환자의불편함, 치료비용등을고려할때사전예방활동이매우중요하며또한사격에의해발생하는이명의예방만으로도이명환자의발생률을감소시킬수있을것이다. Carter 18) 는귀마개를사용하여 Hamel gun에의한음향외상에서청력을보호할수있다고보고하였다. 4년 4 월의정기사격에서 8명의청력손실자가발생하였기때문에 4년 9월의정기사격에서는사격전음향외상에의한청력손실에대한교육을실시하였고오른손잡이에서는좌측귀에, 왼손잡이에서는우측귀에편측만 foam 형태의귀마개를착용하도록한후사격을시행한결과청력손실자 Korean J Otolaryngol 6;49:887-91
문인석 가발생하지않았다. 현재각급부대에서사격시예방교육과개인보호장비의보급이부족한실정이며또한사격의특성상통제관의지시를정확히전달받지못하는경우안전사고의위험성이크기때문에개인보호장구를가지고있는경우에도이의사용을금지하는경우가있다. 그러나본연구결과에따르면편측만보호장구를사용할경우두부음영효과에의해청력손실을예방할수있으면서도반대측귀를통해서사격시통제를따르는데지장이없었다. 따라서편측보호장비착용으로청력손실방지와안전사고예방모두를취할수있을것으로생각된다. 결 론 소음성난청은효과적인치료가없으나예방가능한질환이며특히우리나라에서는젊은남성대부분이병역중총기소음에노출이되고있어이에대한예방이절실히요구된다. 실사격시의위험성과두부음영효과를고려하여사격전편측개인보호장구의철저한착용과지속적예방교육으로음향외상에의한청력손실을방지해야할것이다. 중심단어 : 사격 소음성난청 청력보호장구. REFERENCES 1) Kim HJ. Noise induced hearing loss. in: Kim JS, editors. Otorhinolaryngology Head and Neck surgery. Ilchokak Publishers;2. p.691-7. 2) Phaneuf R, Hetu R. An epidemiological perspective of the cause of hearing loss among industrial workers. J Otolaryngol 199;19:31-. 3) Health standards for occupational noise exposure. Mine Safety and Health Administration (MSHA), Labor. Fed Regist 1999;64:49548-634. 4) Stewart M, Konkle DF, Simpson TH. The effect of recreational gunfire noise on hearing in workers exposed to occupational noise. Ear Nose Throat J 1;8:32-4, 36, 38-. 5) Keim RJ. Sensorineural hearing loss associated with firearms. Arch Otolaryngol 1969;9:581-4. 6) Lim DJ. Functional structure of the organ of Corti: A review. Hear Res 1986;22:117-46. 7) Dobie RA. Noise induced hearing loss in: Bailey BJ, Kohut RI, Vrabec JT, editors. Head and Neck Surgery-Otolaryngology. 2nd ed. Philadelphia: Lippincott-Raven Publishers;1998. p.2153-63. 8) Schleuning AJ Jr. Tinnitus. In: Bailey BJ, Kohut RI, Vrabec JT, editors. Head and Neck Surgery-Otolaryngology. 2nd ed. Philadelphia: Lippincott-Raven Publishers;1998. p.2199-6. 9) Lee ST, Lee Y. The measurement of firing noise of K2 riffle at close distance. Proceeding of Korean Society for Noise and Vibration Engineering 4;14:1123-8. 1) Arnold S, Burkard R. Studies of interaural attenuation to investigate the validity of a dichotic difference tone response recorded from the inferior colliculus in the chinchilla. J Acoust Soc Am ;17:1541-7. 11) Oeken J. Distortion product otoacoustic emissions in acute acoustic trauma. Noise health 1998;1:56-66. 12) Demaertelaere L, Van Opstal M. Treatment of acoustic trauma with hyperbaric oxygen. Acta Otorhinolaryngol Belg 1981;35:3-14. 13) Wilson WR. Why treat sadden hearing loss. Am J Otol 1984;5:481-3. 14) Burschka MA, Hassan HA, Reineke T, van Bebber L, Caird DM, Mosges R. Effect of treatment with Ginko biloba extract EGb 761 (oral) on unilateral idiopathic sudden hearing loss in a prospective randomized double-blind study of 16 outpatients. Eur Arch Otorhinolaryngol 1;258:213-9. 15) Morgenstern C, Biermann E. The efficacy of Ginko special extract EGb 761 in patients with tinnitus. Int J Clin Pharmacol Ther 2; :188-97. 16) Snow JB, Telion SA. Sudden deafness. In: Paparella MM, Shumrick DA, Glukman JL, Meyerhoff WL, editors. Otolaryngology. 3rd ed. Philadelphia: Saunders company;1991. p.1619-28. 17) Cheon KM. Tinnitus. In: Kim JS, editors. Otorhinolaryngology Head and Neck surgery. Ilchokak Publishers;2. p.812-. 18) Carter NL. Effectiveness of foam earplug hearing protection for artillerymen firing L118/119 15 mm howitzers. Mil Med 1989;154:473-6. 891