대한응급의학회지제 24 권제 1 호 Volume 24, Number 1, February, 2013 원 저 기관내관의기낭을팽창시키는방법의비교 : 수동적배출법과최소기낭팽창법 인제대학교일산백병원응급의학과, 연세대학교의과대학응급의학교실 1 허 @ 현 박준민 김경환 신동운 박준석 김 @ 훈 전우찬 신희준 김민정 1 A Comparison of Passive Release Technique and Minimal Occlusive Volume Technique for Endotracheal Tube Cuff Inflation Hyun Hur, M.D., Joon Min Park, M.D. Kyung Hwan Kim, M.D., Dong Wun Shin, M.D., Jun Seok Park, M.D., Hoon Kim, M.D., Woo Chan Jeon, M.D., Hee Jun Shin, M.D., Min Joung Kim, M.D. 1 Purpose: Inflation of an endotracheal tube cuff with adequate pressure is an important procedure. Passive release technique (PRT) is a useful and convenient method for inflating the cuff. To date, no study comparing this method with minimal occlusive volume technique (MOVT), one of the most commonly used methods for inflating the cuff, has been reported. We conducted this study for comparison of effectiveness, difficulty, and preference between the two methods. Methods: We conducted a prospective, crossover, randomized study in which participants used each technique, one at a time. Participants inflated the cuff of an endotracheal tube inserted into a manikin after receiving brief education on use of the two methods. After inflating the cuff using each method, pressure and volume of the inflated cuff were measured using a portable manometer and syringes, respectively. Then, difficulty of each method was investigated using the visual analogue scale (VAS) and preference for each method was investigated. Results: A total of 47 participants were enrolled in the study. The mean pressure between the two methods was 책임저자 : 박준민경기도고양시일산서구대화동 2240 인제대학교일산백병원응급의학과 Tel: 031) 910-7119, Fax: 031) 910-7188 E-mail: aero7@paik.ac.kr 접수일 : 2012년 10월 31일, 1차교정일 : 2012년 11월 12일게재승인일 : 2013년 1월 26일 95 not statistically different (p=0.27). However, adequate pressure was achieved in 37 (78.7%) and 16 (34.0%) of participants in PRT and MOVT, respectively (p<0.01). The mean volume was 6.0±0.4 ml in PRT and 5.7±0.6 ml in MOVT (p<0.01). The VAS score for diffculty was 17.7±15.8 in PRT and 76.0±15.8 in MOVT (p<0.01). Preference for PRT was 46(97.9%) and that for MOVT was 1 (2.1%). Conclusion: PRT is an easier, more preferred, and more effective method for cuff inflation than MOVT. Key Words: Intubation, Pressure, Manikins, Syringe Department of Emergency Medicine, Inje University Ilsan Paik Hospital, Goyang, Korea, Department of Emergency Medicine, Yonsei University College of Medicine, Seoul, Korea 1 서 공기로채워진기관내관의기낭 (cuff) 은위, 식도또는인두의내용물이기도로흡인되거나양압환기시에환기가스가새는것을막아주는역할을한다 1). 기낭이과소팽창될경우이와같은고유의역할을기대할수없으며, 반대로과다팽창될경우기낭의압력이기관점막벽과주위구조에과하게전달되어기관점막벽의허혈을야기한다 2). 기낭의압력이 30 cmh 2O 보다클경우기도점막의혈류가떨어지기시작하며, 50 cmh 2O 보다클경우혈류가중단된다는연구가있다 3). 이와같이적절한압력으로기낭을팽창시키는것이중요하지만아직까지적절한압력에대해명확한합의는없으며, 앞선연구에따르면 15~30, 20~30 25~40 cmh 2O 정도로다양하게권고하고있다 1,4-8). 기낭이기관벽에가하는압력은기관과기낭의유순도에따라결정되는데, 길잡이풍선 (pilot balloon) 에서측정한압력은이를예측하는좋은척도로여겨진다 2). 기낭을적절한압력으로팽창시키기위해서는간단한아네로이드압력계를이용하여길잡이풍선에서압력을측정하는것이추천되나, 이장비가없거나사용경험이없는이유로현장 론
96 / 대한응급의학회지 : 제 24 권제 1 호 2013 에서는여러고식적인방법이사용되고있다 6,9). 그중최소기낭팽창법 (minimal occlusive volume technique) 은기관삽관후백-밸브환기시, 기낭이충분히부풀려지지않았을경우환기가스가새는원리를이용한방법으로시술자가목에서청진을통해환기가스가새지않는최소한의기낭팽창지점을찾는방식이다. 이최소기낭팽창법은적절한기낭팽창방법으로널리사용되고있으며, 호주및뉴질랜드의성인중환자실에서조사한바에따르면압력계를이용하여직접압력을확인하는방법과더불어가장흔히이용되는방법이다 2,10). 수동적배출법 (passive release technique) 은미리정해진용량의공기를주사기로주입하여기낭을팽창시킨후주사기를길잡이풍선에연결해두면기낭과기관벽의탄력에따라기낭의여분의공기가주사기로돌아오는원리를이용한방법으로, 적절한압력으로기낭을팽창시키는데도움이되는것으로알려져있다 1,11-13). 수동적배출법은수동적배출에따른시술자간변이가적다는장점이있고간편한방법으로응급상황에서적용이용이한방법이지만, 가장널리쓰이는효과적인방법중하나인최소기낭팽창법과의직접적인비교는없었다 12). 따라서본연구에서는수동적배출법과최소기낭팽창법에서기낭의압력및부피를비교하고각방법의난이도와선호도를비교하고자하였다. 대상과방법본연구는전향적무작위교차연구로일개대학병원에서이루어졌다. 참가자는원내에서실시한기도관리교육과정을이수한임상경력 1년이상의의사, 간호사, 응급구조사를대상으로원내메일을통해모집하였으며, 연구참여에동의하지않은경우는제외하였다. 우선참가자들에게수동적배출법과최소기낭팽창법에대한 10분간의강의를한후각방법을 1회인체모형 (ALS Skillmaster, Laerdal, Stravanger, Norway) 에연습하는과정을가졌고, 이후한시간이지난시점에본실험을진행했다. 각참가자는컴퓨터무작위배정프로그램에서정한순서에따라두방법을순차적으로시행했다. 내경 7.5 mm 기관내관인 PharmaPlast Murphy (Pharmplast Ltd, Redditch, UK) 를인체모형에기관삽관하고윗입술기준으로 21 cm에고정한상태에서연구를진행했다. 수동적배출법의경우 10 ml 일회용주사기 (BD medical, Temse, Belgium) 에기존연구에서와같이 12 ml의실내공기를넣은후천천히길잡이풍선을통해주입한후연결된채로두었고이과정에서팽창된기낭은기관벽에다시눌려주사기로여분의공기가돌아오게된다 10) (Fig. 1). 더이상주사기로공기가밀려나오지않으면연구자는휴대용기낭압력계 (Cuff Pressure Gauge, VBM Medizintechnik GmbH, German) 를이용하여기낭의압력을측정하고, 기 A B C Fig. 1. Brief explanation of passive release technique for cuff inflation. (A) First, 10 ml disposable syringe filled with 12 ml of air was connected to pilot balloon. (B) Second, 12 ml of air was injected slowly until the plunger was compressed to the top of syringe. (C) Third, the plunger was allowed to passively rebound to a steady pressure at which the plunger stopped.
허 @ 현외 : 기관내관의기낭을팽창시키는방법의비교 : 수동적배출법과최소기낭팽창법 / 97 낭이납작해질때까지주사기로공기를빼내어기낭의부피를측정하였다. 최소기낭팽창법은연구보조자 1인이백-밸브환기 (bag valve ventilation) 를시행하였고, 동시에참가자는청진기 (Littmann Cardiology, 3M, Bracknell, UK) 를인체모형의갑상연골위치의좌측에대고서서히주사기로기낭을부풀리면서호흡소리의변화를확인하여거친소리가부드러운소리로바뀌는시점을적절한기낭팽창시점으로결정했다 (Fig. 1). 마찬가지로기낭의압력과부피를측정했으며, 두방법을모두시행한후각방법에대한선호도와난이도를설문지를통해조사했다. 난이도의경우 100 mm 시각아날로그척도 (Visual Analogue Scale, VAS) 를사용하였으며, 0을가장쉬운난이도로 100을가장어려운난이도로설정했다. 연구결과는통계프로그램인 SAS version 4.2 (SAS Inc, Cary, NC) 를사용하여분석했다. 연속형변수는평균 ± 표준편차로, 범주형변수는빈도수와백분율 (%) 로표시하였다. 각방법의압력, 부피의비교는대응표본 t검정 (paired t test) 을이용했고, 각방법의난이도비교는독립표본 t검정 (independent t test) 을이용했다. 적절한압력의범위는기존연구에제시된대로 25~40 cmh 2O로설정했으며, McNemar s 검정을이용하여양군에서성공적으로적절한압력내에분포한비율을비교하였다 1,7,8). p값이 0.05 미만일경우통계적으로의미있는결과로판정했다. 결과 1. 연구참가자의일반적특성총 47명이본연구에참여했으며, 중도탈락한경우는없었다. 참가자의성별은남자 9명, 여자 38명이었으며직종은의사 9명, 응급구조사 4명, 간호사 34명이었다. 임상경력은평균 4.7년 (1~23년) 이었다. 2. 기낭팽창방법에따른기낭압력과부피의비교기낭압력은수동적배출법의경우 34.5±8.2 cmh 2O였으며, 최소기낭팽창법의경우 31.7±16.5 cmh 2O을보였으나통계적으로유의한차이는없었다 (Table 1). 하지만기낭의압력이 25~40 cmh 2O의범위에분포한비율은수동적배출법에서 37명 (78.7%), 최소기낭팽창법에서 16명 (34.0%) 였으며통계적으로유의한차이를보였다 (p<0.01) (Fig. 3). 기낭의부피는수동적배출법의경우 Fig. 2. Brief explanation of minimal occlusive volume technique for cuff inflation. Air was injected slowly until harsh turbulent breath sound was replaced by softly pitched sound during the inspiratory phase. Fig. 3. Distribution of cuff pressures in passive release technique (PRT) and minimal occlusive volume technique (MOVT). The proportion of appropriate pressure in PRT (78.7%) was higher than in MOVT (34.0%) with statistical significance (p<0.01) Table 1. Cuff pressure and volume in PRT* and MOVT PRT MOVT p-value Pressure (cmh 2O) 34.5±8.2 31.7±16.5 <0.27 [32.2~36.9] [27.1~36.5] Volume (ml) 06.0±0.4 5.7±0.6 <0.01 * PRT: passive release technique, MOVT: minimal occlusive volume technique. The results are expressed as mean±standard deviation [95% confidence interval for mean].
98 / 대한응급의학회지 : 제 24 권제 1 호 2013 6.0±0.4 ml, 최소기낭팽창법의경우 5.7±0.6 ml 이었다 (p<0.01)(table 1). 3. 기낭팽창방법에따른난이도및선호도각방법에대한난이도시각아날로그척도는수동적배출법의경우 17.7±15.8점, 최소기낭팽창법의경우 76.0± 15.8점으로유의한차이를보였다 (p<0.01). 각방법에대한선호도조사에서는수동적배출법을선호한참가자는 46명 (97.9%) 이었고, 최소기낭팽창법을선호한참가자는 1명 (2.1%) 이었다. 고찰임상에서기관삽관은기도보호, 환기보조의목적으로시행되는중요한시술이다. 성인의경우기관내관원위부에달려있는기낭이중요한역할을하는데, 기낭이충분히팽창되지않을경우기관으로흡인및이로인한흡인성폐렴이발생할수있으며, 양압환기시환기가스가새어충분한일회호흡량을확보할수없다. 한편기낭이지나치게팽창될경우기관점막의괴사, 기관협착등을유발할수있고심한경우기관파열까지유발할수있다 14-17). 초기기관내관의기낭은딱딱한고무로되어있어기관상피손상이빨리진행되었으나, 높은기낭압력에따른합병증들이보고되면서낮은압력에서도기관의모양에따라잘변형되어허혈성손상을줄이는고부피-저압력 (high volume-low pressure) 기낭이 1960년대말부터개발되어사용되었다 11,18). 그러나응급실이나병원전단계에서시행된기관삽관에대해조사한연구들에서여전히기낭을과도하게팽창시키는경우가많았고, 기낭의과팽창을인지하지못하는비율도 80~100% 로높게나타났으며, 이에따라적절한기낭압력을유지하는기낭팽창방법에대한연구가많이진행되고있다 5,7,19,20). 기낭팽창시기낭압력을직접측정하는것이가장정확한방법이며실제로중환자실이나수술실등에서는기낭압력을측정하며지속감시하는추세인반면, 응급실이나병원전단계에서는측정장비를구비하지못한점, 시술자의선호도및편의성, 압력계영점조절문제, 환자의두부위치및기관내관위치에따른압력의민감한변화등의이유로기낭압력을간접적으로추정하는방법을많이쓰고있다 1,12,18). 그방법으로기낭에공기를주입하며길잡이풍선의팽창을촉지하여주입량을결정하는공기풍선촉지법 (pilot balloon palpation technique), 기낭에공기를주입한후기관내관을통한흡기호흡시환기가스가새는최소한 (50~100 ml 정도의일회환기량손실이예상되는 ) 의시점까지공기를빼는최소유출법 (minimal leak technique), 공기의주입량을미리정해놓는사전결정용적팽창법 (predetermined volume method), 최소기낭팽창법등이사용되고있지만, 어떤방법이더이상적인지에대한합의는아직까지없다 1,11,21). 공기풍선촉지법은전통적으로많이쓰여온간단한방법이지만시술자간, 기관내관종류에따라기낭의압력에차이가많고, 기낭의압력을실제보다낮게예측하여부정확한단점이있어추천되지않는방법이다 7,19,22,23). 최소유출법도간단하지만시술자간차이가크고흡인가능성이높은단점이있으며 24), 사전결정용적팽창법은기낭의압력이높게측정되는경우가많고적절한기낭압력을위해주입되는공기부피를조사한연구에서주입된공기부피의최소량과최대량의차이가 5.6배이상차이를보여실제로적용하기에문제점이많다 5,24,25). 최소기낭팽창법은가장널리쓰이고선호되는방법중의하나로, 기계환기및중환자치료분야에서기관삽관후초기에기낭을팽창하는주된방법으로알려져있다 2,18). 또한기계호흡을하는환자에서지속적으로기낭의압력을적절히유지하는지감시하는용도로사용할수있으며, 이경우현재가장정확하다고알려져있는직접적인압력측정방법인기낭압력감시 (cuff pressure monitoring) 방식과더불어가장추천되는방법이다 18). 하지만측정을위해양압환기를중단해야하고그결과호기말양압의손실및저산소증유발이가능하고흡인의위험, 기낭재팽창시과팽창의가능성및반복적인사용으로기낭밸브의손상이가능한단점이있다 18). 또한응급실이나사고현장등의병원전단계에서주변소음이클경우에는사용하기어렵다. 한편수동적배출법은 Somri 등 13) 에의해비교적최근에소개된방법으로기낭의과압방지용일방향밸브특성상기낭이과도하게팽창될경우기관벽에눌려수동적으로공기가밀려나오는원리를이용한다. Huh 등 1) 의사람을대상으로한전향적연구에서기관삽관초기에기낭을적절하게팽창시키는방법으로수동적배출법을사용했으며, 20 ml 주사기를사용할때보다 10 ml 주사기를사용할때적절한압력으로기낭을팽창시킬수있었다. 20 ml 주사기를사용할때는적절한기낭압력보다낮은압력을보였으며, 이는부피가큰주사기일수록주사기의원통내벽과플런저 (plunger) 의윤활제처리된접촉면이증가하여마찰저항이덜걸리기때문이었다. 수동적배출법은인체모형을이용한연구에서도기낭을적절히팽창시키는간편한방법임이증명되었으며 11,12), 본연구에서는 Huh 등 1) 의연구및 Park 등 11) 의연구에서와같이 10 ml 일회용주사기를이용하여 12 ml의공기를주입하는방식으로연구를진행했다. 수동적배출법과최소기낭팽창법을비교한본연구에서, 기낭압력의절대값은두방법에서통계적인차이를보이지않았지만적절한압력의범위에포함된비율은수동적배출법에서훨씬높았으며, 이는기낭압력이적절한범
허 @ 현외 : 기관내관의기낭을팽창시키는방법의비교 : 수동적배출법과최소기낭팽창법 / 99 위에서유지되는것이중요하다는점에서큰의미를갖는다. Huh 등 1) 이사람을대상으로조사한연구에서 25~40 cmh 2O의적절한압력에분포하는비율은기관내관의종류에따라 56.0%, 63.2% 였으며, Park 등 11) 이인체모형에실시한연구에서는적절한압력에대한기준이달라직접적인비교는어렵겠으나 65.5% 로본연구보다낮은비율을보였다. 압력의절대값과적절한압력에분포한비율이이전연구들과차이를보이는이유는다른연구에서는실험대상이사람및다른종류의인체모형이었으며, 기관내관의종류나주사기의종류가다르기때문으로추측된다. 기낭부피의경우두방법간큰차이를보이지않았으며, 수동적배출법의경우사람을대상으로한 Huh 등 1) 의연구에서 7.8±1.6 ml, 인체모형을대상으로한 Park 등 11) 의연구에서 8.5±1.2 ml 보다는적은부피를보였는데이역시기관내관의종류및실험대상의차이에기인한것으로생각된다. 시술방법을임상에적용시키기위해서는시술자가느끼는주관적인난이도나선호도도매우중요한데, 본연구에서수동적배출법이최소기낭팽창법에비해훨씬낮은난이도와높은선호도를보인것으로조사되었다. 수동적배출법은혼자시술이가능하고시술도구로주사기만필요한간편한방법인반면, 최소기낭팽창법은시술과정동안보조자가백-밸브환기를지속적으로시행해야하고시끄러운주변환경에서적용할경우청진을통한적절한기낭팽창시점을찾기가어려울수있으며, 청진소견에의존하기때문에시술자간오차가생길가능성이높다는점에서높은난이도와낮은선호도를보인것으로생각된다. 이번연구는몇가지제한점이있다. 첫째, 실리콘과플라스틱으로이루어진기도구조의특성및딱딱한피부로덮인인체모형의특징을고려할때이연구의결과를실제환자에바로적용하는데제한이있다. 둘째, 참가자의각기낭팽창방법에대한능숙도에따라결과가달리질수있다는점을고려하지못했다. 사전조사에서본연구에서사용된기낭팽창방법에익숙한참가자는없었으며실험에앞서시행한교육및연습과정만으로는각방법에대해능숙할수없었다. 셋째, 본연구의경우기관내관의종류및크기, 주사기의종류, 용량및크기, 기도내기낭의위치등여러임상상황에서기낭의압력및부피에영향을미칠수있는변수들을고려하지못했다. 마지막으로본연구는성인용기관내관을이용한연구로소아환자에서바로적용하기는어렵다. 결론최소기낭팽창법과비교하여수동적배출법을사용할경우, 더적절한압력으로기낭을팽창시키는것을확인할 수있었다. 또한수동적배출법이최소기낭팽창법에비해시행하기더쉬운시술로조사되었고, 더높은선호도를보였다. 직접적인기낭의압력을측정하는것이불가능한상황에서일회용주사기를이용한수동적배출법이유용한기낭팽창의도구로사용될수있을것이다. 참고문헌 01. Huh J, Yoon TG, Kwon WK, Joo Y, Kim DK. Usefulnessof new technique using a disposable syringe for endotracheal tube cuff inflation. Korean J Anesthesiol 2009;56:513-8. 02. Sultan P, Carvalho B, Rose BO, Creqq R. Endotracheal tube cuff pressure monitoring: a review of the evidence. J Perioper Pract 2011;21:379-86. 03. Seegobin RD, Van Hasselt GL. Endotracheal cuffpressure and tracheal mucosal blood flow: endoscopicstudy of effects of four large volume cuffs. Br Med J 1984;288: 965-8. 04. Nseir S, Duguet A, Copin MC, De Jonckheere J, ZhangM, Similowski T, et al. Continuous control of endotracheal cuff pressure and tracheal wall damage: a randomizedcontrolled animal study. Crit Care 2007;11:R109. 05. Kang MS, You KC, O SH, Kim JH, Ahn ME, Park WJ, et al. Investigations of the air volume for a tracheal tube cuffin a tracheal models. J Korean Soc Emerg Med 2006; 17:14-8. 06. Sengupta P, Sessler DI, Maglinger P, Wells S, Vogt A, Durrani J, et al. Endotracheal tube cuff pressure in three hospitals, and the volume required to produce an appropriatecuff pressure. BMC Anesthesiol 2004;4:8. 07. Parwani V, Hoffman RJ, Russell A, Bharel C, Preblick C,Hahn IH. Practicing paramedics cannot generate or estimate safe endotracheal tube cuff pressure using standard techniques. Prehosp Emerg Care 2007;11:307-11. 08. Morris LG, Zoumalan RA, Roccaforte JD, Amin MR. Monitoringtracheal tube cuff pressures in the intensive care unit: a comparison of digital palpation and manometry. Ann Otol Rhinol Laryngol 2007;116:639-42. 09. Chopra M, Jones L, Boulanger C, Benger J, Higginson I, Williamson D, et al. Prospective observational measurement of tracheal tube cuff pressures in the emergency department. Emerg Med J 2010;27:270-1. 10. Rose L, Redl L. Survey of cuff management practices in intensive care units in Australia and New Zealand. Am J Crit Care 2008;17:428-35. 11. Park KC, Sohn YD, Ahn HC, Ahn JY, Park SM, Cho KY, et al. Effectiveness, preference and ease of passive release techniques using a syringe for endotracheal tube cuff inflation. J Korean Soc Emerg Med 2010;21:795-800.
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