Journal of the Korean Dysphagia Society 2014;4:23-27 Original Article 뇌졸중환자에서호흡기능과연하장애의연관성 양혜은 1 ㆍ박윤길 1 ㆍ김선미 2 1 연세대학교의과대학재활의학교실및희귀난치성신경근육병재활연구소, 2 제주대학교의과대학제주대학교병원재활의학교실 Correlation between Respiratory Function and Dysphagia in Stroke Patients Hea Eun Yang, M.D. 1, Yoon Ghil Park, M.D., Ph.D. 1, Sun Mi Kim, M.D. 2 1 Department of Rehabilitation Medicine and Rehabilitation Institute of Neuromuscular Disease, Yonsei University College of Medicine, Seoul, 2 Department of Rehabilitation Medicine, Jeju National University Hospital, Jeju University School of Medicine, Jeju, Korea Objective: Dysphagia is a very common complication of stroke and is can be a marker of poor prognosis. In addition altered respiratory function is also observed in stroke patients. The purposes of this study are to find out correlations between dysphagia and respiratory function, and if specific parameter of respiratory function can screen patients at high risk of aspiration. Method: 37 adult stroke patients were enrolled (18 in aspirated group, 19 in non-aspirated group). All patients underwent video fluoroscopic swallowing study (VFSS) and pulmonary function test (PFT) including forced vital capacity (FVC), forced expiratory volume at one second (FEV1), and peak cough flow (PCF). Diaphragmatic motion during breathing was measured through fluoroscope and end-tidal CO2 (EtCO2) was measured on resting state. Patients were separated into two groups in term of aspiration. Result: The FVC of aspirated group (48.5±14.1%) was significantly lower than that of non-aspirated group (57.2±9.95%) (P=0.036). The FEV1 of aspirated group (43.3±15.3%) was also significantly lower than that of non-aspirated group (53.8±15.6%) (P=0.047). Other parameters and patient characteristics did not show significant differences. Conclusion: FVC is considered an important factor to expect aspiration on swallowing in stroke patients. So PFT including FVC and FEV1 could be a useful method to screen stroke patients at high risk of aspiration. (JKDS 2014;4: 23-27) Keywords: Stroke, Dysphagia, Pulmonary function test 서론 뇌졸중후에는중추성횡격막기능장애 (central diaphragmatic dysfunction) 가동반되며, 뇌졸중으로인한운동장애는횡격막움직임 (diaphragmatic motion) 의제한을야기하고이는폐용적의감소로이어진다 1. 마비로 투고일 : 2014 년 1 월 3 일, 심사일 : 2014 년 1 월 6 일, 게재확정일 : 2014 년 1 월 8 일책임저자 : 박윤길, 서울시강남구언주로 211 (135-720) 연세대학교의과대학재활의학교실및희귀난치성신경근육병재활연구소 Tel: 02) 2019-3490, Fax: 02) 3463-7585 E-mail: drtlc@yuhs.ac Copyrights c The Korean Dysphagia Society, 2014. 23
24 Hea Eun Yang, et al.:correlation between Respiratory Function and Dysphagia in Stroke Patients 인한호흡근육의위상성 (phasic) 과긴장성 (tonic) 운동양상의변화는호흡근육의약화와호흡양상의변화, 그리고폐용적의감소를일으켜호흡기계의중대한변화를초래한다 2,3. 이러한기전을통해감소된폐용적은뇌졸중환자에서제한성호흡질환 (restrictive respiratory disease) 을야기한다 3. 호흡기능과연하작용은여러해부학적구조를공유하며기도보호라는중요한기능을담당하는데, 특히기침과연하작용은둘다기도보호행태 (airway-protective behavior) 로인두, 후두, 기관의수용체가연수로신호를전달함으로써시작되며 behavior control assemblies (BCAs) 라는뇌간의네트워크를공유한다 4,5. 신경학적질환인파킨슨병환자에서호기최대유량 (expiratory phase peak flow) 의정량적측정을통해연하장애를예측할수있으며뇌졸중환자에서연하장애가있는경우연하장애가없는경우보다노력성폐활량 (forced vital capacity, FVC) 과최대기침유량 (peak cough flow, PCF) 이낮은것으로확인되었다 6,7. 뇌졸중환자에서감각저하로인한후두반사기침 (laryngeal reflex cough) 의감소가흡인성폐렴의지표가되며수의적기침 (voluntary cough) 의정량적측정을통해기도흡인의위험도를평가한연구에서는정상군에비해기도흡인이있는뇌졸중환자에서흡기와호기시의최대유량등이더낮음을밝혔다 8,9. 또한강한수의적기침은음식물이기도로들어간이후에도이물제거를통해흡인성폐렴을줄일수있어, 삼킴중투과 (penetration) 나흡인이발생하더라도기침을통해흡인성폐렴의발생을낮출수있다 9,10. 뇌졸중환자에서기도흡인은흔하게나타나며, 이는흡인성폐렴등의중대한합병증을일으키므로기도흡인을발견하고적절한치료를시행하는것이예후에매우중요하다 11,12. 기도흡인을진단하는데표준검사로사용되는비디오투시연하검사 (video fluoroscopic swallowing study, VFSS) 는진단에매우민감하지만많은경우검사를하기까지시간이걸리고환자의자세나협조에따라검사에제한이있다 13. 비디오투시연하검사전미리기도흡인의고위험군을알수있다면검사가필요한환자를선별할수있고비디오투시연하검사를통한진단전에보다빠른중재를통해기도흡인을예방할수있을것이다. 기도흡인의고위험군을찾아내는방법에는임상증상으로선별하는방법과여러가지침상검사 (bedside test) 를시행하는방법이널리사용되고있으나, 이러한방법은뇌졸중후발생하는기도흡인을진단하거나환자의치료에활용하기에는부적합한것으로나타났다 14. 삼킴반응없음 (absent swallow), 분비물처리곤란 (difficulty handling secretions), 물삼킴후기침반사 (reflex cough after water bolus) 등의임상증상은민감도 58%, 특이도 83% 로나타났고여러방법의침상검사결과를비디오투시연하검사와대조한연구에따르면민감도는 42-92%, 특이도는 59-91% 로나타났으며검사자간신뢰도역시다양한것으로확인되었다 4,11. 이에따라임상증상이나침상검사를보완할수있는간편하고정확한평가방법의필요성이대두되고있다. 위에서언급한바와같이호흡기능과연하장애는밀접한관계가있으나이에대한연구는매우제한적으로이루어지고있다. 따라서본연구에서는뇌졸중환자에서연하장애와호흡기능의연관성을알아보고연하장애와관련된지표를파악하고자하였다. 대상및방법 1. 연구대상 뇌졸중으로인한연하장애를호소하는재활의학과입원환자 37 명을대상으로하였다. 포함기준은자기공명영상과컴퓨터단층촬영을통해최초로뇌경색또는뇌출혈을진단받은환자, 18 세이상의성인, 심폐질환이없는경우, 검사를충분히이해하고수행할만한인지기능, 의자에앉은자세를유지하고비디오투시연하검사와최대노력으로폐활량측정이가능한경우로하였다. 기존에연하장애가있었거나기관절개를시행한환자는연구에서제외하였다. 모든환자에서발병 1 년이내인시점에검사를시행했다. 2. 방법 모든환자에서비디오투시연하검사를시행하였고, 비디오투시연하검사시행당일호흡기능평가를시행하였다. 호흡기능평가를위해노력성폐활량, 최대기침유량, 1 초간강제호기량 (forced expiratory volume at one second, FEV1) 을측정하였다. 침상혹은휠체어에앉은자세에서코와입을완전히덮도록안면부에마스크를밀착하고이동형폐활량계 (portable spirometer)(micro R, Micro Medical Ltd., England) 와기침유량측정기 (Assess R, Respironics, United States) 사용하여측정하였다. 노력성폐활량에대한 1 초간강제호기량의비율을구하였고측정한폐활량, 최대기침유량, 1 초간강제호기량을각각정상예측치와비교한비율을계산하였다. 투시검사는앉은자세에서최대호기와흡기를한상태에서횡격막의움직
양혜은외 : 뇌졸중환자에서호흡기능과연하장애의연관성 25 임을갈비뼈를기준으로양측을각각측정하였다. 호기말이산화탄소분압은환자가앉아서편하게숨을쉬는상태에서이동형이산화탄소분압측정기 (portable capnograph) (Microstream R, Oridion Medical Ltd., Israel) 의탐측기 (probe) 를환자의코에대고 3 차례이상측정하여평균을구하였다. 비디오투시연하검사는한명의재활의학과전문의가판독했고, 호흡기능평가는비디오투시연하검사의결과를모르는다른재활의학과의사가시행하였다. 기도흡인은검사중어느때라도음식물이성대주름을통과하는경우로정의하였고, 성대주름통과후기침등을통해음식물이제거된경우는고려하지않았다. 호흡기능평가전 1 주이내에인지를한국형간이정신상태검사 (K-MMSE, Korean mini-mental state examination) 로평가하였고, 기능적상태는기능적독립성측정 (FIM, functional independence measure) 으로평가하였다. 비디오투시연하검사로확인된기도흡인이있는군과없는군의두그룹으로분류하였고두그룹의특성은 Table 1 에나타냈다. 3. 통계분석 두군간의특성을비교하기위해독립표본 T 검정 (independent-t test) ( 나이, 이환기간, 신체질량지수, 기능적독립성측정, 한국형간이정신상태검사 ) 과카이제곱검정 (χ 2 test) ( 성별, 뇌졸중부위, 마비부위 ) 을시행하였다. 정규성검정후노력성폐활량, 최대기침유량, 1 초간강제 Table 1. Characteristics of subjects. Number Sex, male Mean Age (yr) Disease duration (days) Lesion Supratentorial (%) Infratentorial (%) Hemi side Rt. Side (%) Lt. side (%) Quadri (%) K-MMSE FIM No aspiration 19 9 (47.4%) 58.9±14.4 54.6±83.6 14 (73.7%) 5 (26.3%) 7 (36.8%) 10 (52.6%) 2 (10.5%) 25.9±2.7 80.1±25.6 Aspiration 18 12 (66.7%) 58.8±14.2 77.7±99.6 10 (55.6%) 8 (44.4%) 5 (27.8%) 7 (38.9%) 6 (33.3%) 24.8±4.0 80.3±27.1 P-value 0.236 0.990 0.450 0.262 0.199 0.328 0.944 K-MMSE: Korean mini-mental state examination, FIM: functional independence measure. 호기량, 1 초간강제호기량 / 노력성폐활량, 호기말이산화탄소분압은독립표본 T 검정으로, 횡격막움직임은 Mann- Whitney 검정으로분석하였다. 노력성폐활량과 1 초간강제호기량이서로혹은환자의특성들과상관관계를갖는지확인하고자 Pearson 의상관계수 (Pearson s correlation coefficients) 를구하였다. 결과 37 명의환자중비디오투시연하검사상기도흡인은 18 명 (48.6%) 에서관찰되었다. 기도흡인이있는군 (18 명 ) 과없는군 (19 명 ) 의일반적인특성은통계학적으로차이가없었다 (Table 1). 키와나이를고려한정상예측치에대한노력성폐활량의비율은기도흡인이발생하지않은군에서 57.2±9.9%, 기도흡인이발생한군에서 48.5±14.1% 로통계적으로유의한차이를보였다 (P=0.036). 키와나이를고려한정상예측치에대한 1 초간강제호기량의비율은기도흡인이발생하지않은군에서 53.8±15.6%, 기도흡인이발생한군에서 43.3±15.3% 로통계적으로유의한차이를보였다 (P=0.047). 노력성폐활량과 1 초간강제호기량은기능적상태와는상관관계를보이지않았으나두가지는서로상관계수 0.767 로양의상관관계를가졌다. 기도흡인군과비흡인군에서기능적독립성측정과간이정신상태검사점수는차이를보이지않았다. 호흡기능평가항목중호기능력을반영하는최대기침유량은기도흡인이있는군에서 195.6±86.4 ml, 기도흡인이없는군에서 222.6±87.1 ml (P=0.349), 노력성폐활량에대한 1 초간강제호기량의비율은기도흡인이있는군에서 59.5±18.2%, 기도흡인이없는군에서 63.8±13.1% (P=0.425) 로두가지항목모두기도흡인이있는군에서 Table 2. Spirometric parameters, diaphragm motion and EtCO2. FVC (%) FEV1 (%) FEV1/FVC (%) PCF (ml) Diaphragm motion, Rt. (rib) Diaphragm motion, Lt. (rib) Mean EtCO2 (mmhg) No aspiration 57.2±9.9 53.8±15.6 63.8±13.1 222.6±87.1 1.6±0.5 1.4±0.5 35.0±7.4 Aspiration 48.5±14.1 43.3±15.3 59.5±18.2 195.6±86.4 1.1±0.5 1.1±0.5 35.0±5.7 P-value 0.036 0.047 0.425 0.349 0.004 0.053 0.996 FVC: forced vital capacity, FEV1: forced expiratory volume at one second, PCF: peak cough flow, EtCO2: end-tidal CO2.
26 Hea Eun Yang, et al.:correlation between Respiratory Function and Dysphagia in Stroke Patients 더낮은경향성을보였으나통계적유의성은없었다. 횡격막의움직임은우측에서는두군간에통계적으로유의한차이를보였으나 (P=0.004) 좌측에서는유의한차이를보이지않았다. 호기말이산화탄소분압은두군에서차이를보이지않았다. 모든결과는 Table 2 에나타냈다. 고찰 뇌졸중후에는마비측의횡격막과늑간근, 복근의약화가발생하며정상군에비해호흡하는동안흉곽움직임의기여도가낮아져결과적으로폐용적의감소를초래한다 1-3. 그러나뇌졸중환자에서이러한폐용적의감소가기도흡인과어떠한연관성을가지는지는밝혀진바가없다. 연하작용동안에는기도흡인을막기위해대략 0.3-1 초간의호흡정지 (breathing pause) 가일어나는데이러한삼킴중무호흡 (swallow apnea) 은호기의마지막시기부터시작되어다음호흡주기시작직전까지지속되며이시간은음식물의덩어리 (bolus) 가클수록길어진다 15,16. 삼킴중무호흡은삼킴중기도흡인을예방하는중요한기전중하나로폐용적이큰경우그렇지않은경우보다삼킴중무호흡이긴시간동안완전하게일어나기도흡인예방효과가있었으리라생각된다 16. 실제로만성폐쇄성폐질환환자들에서삼킴중무호흡기간이정상인에비해짧은것을확인하였고 ( 정상군 654 ms, COPD 환자군 641 ms) 이렇게호흡 - 삼킴의조화가깨짐으로만성폐쇄성폐질환환자들에서기도흡인의위험도가증가한다고보고된바가있다 17. 본연구에서기도흡인이발생한군에서그렇지않은환자들보다노력성폐활량이낮았고, 노력성폐활량에대한 1 초간강제호기량의비율은유의한차이없이 1 초간강제호기량의값이낮게측정되어, 기도흡인이있는뇌졸중환자에서기능적폐용적이보다낮음을확인하였다. 호흡기능중주로호기능력, 특히기침은기도보호기전이라는측면에서기도흡인과밀접한연관이있으며수의적기침과반사기침모두에서기침의강도와기도흡인의위험도가상관관계가있다는결론을도출한연구도있었다 18. 본연구에서는호기기능을나타내는최대기침유량과노력성폐활량에대한 1 초간강제호기량의비율은기도흡인이있는군에서더작은경향성은보이나그차이가통계적으로의미있지는않았다 (Table 2). 본연구의대상군이총 37 명으로적은수임을감안하였을때추후더많은환자를대상으로호기기능에서어떠한차이를보일지확인이필요하겠으나, 호기기능보다폐용적자체가기 도흡인과더연관성이있다고생각된다. 호기말이산화탄소분압은두군간차이를나타내지않았는데, 이는기도흡인이있는군의폐용적감소가휴식중환기저하를일으킬수준은아님을시사한다고하겠다. 기도흡인이있는경우폐용적이더적어양측횡격막의움직임도저하되어있으리라기대했는데, 우측에서는두군간유의한차이를보였으나좌측에서는차이를보이지않았다. 2011 년에이루어진 Widdicombe 등의연구에따르면횡격막의움직임을엑스선투시로촬영한후비디오로기록해숙련된두명의의사가각각비디오를재생하면서 cm 단위로측정했을때신뢰성을가진다고했다 19. 뇌졸중환자에서횡격막의움직임을측정한다른연구에서도엑스선투시화면에서횡격막의움직임을 mm 단위로측정하여결론을도출하였었다 1,20. 본연구에서는실시간으로횡격막움직임을측정했는데방사선조사를줄이고또최대호기, 흡기중호흡을참는시간동안의빠른측정을위해갈비뼈를기준으로횡격막움직임을측정했다. 때문에정밀한측정이되지않았을가능성이높아추후연구에서횡격막움직임을측정할때는비디오로기록하여반복재생을통해더정밀한단위로측정을할필요가있겠다. 본연구는환자의협조가필수적인폐기능검사의특성상 MMSE 가전체평균 25.4 점, FIM 이전체평균 81 점으로인지와기능이비교적잘유지되는환자를대상으로하였기때문에선택오차의가능성이있고, 대상이총 37 명으로적다는제한점이있다. 이러한제한점들을보완하고, 비디오투시연하검사중투과또는기도흡인에따른반사성혹은수의적기침이동반되었는지여부와추적관찰을통해실제흡인성폐렴의발생여부를추가조사한다면보다명확히연하장애와폐기능의관련성을밝힐수있으리라기대한다. 또한향후호흡기능이호전되면연하장애도회복이되는지에대한추적관찰연구가필요할것으로생각된다. 결론 본연구는뇌졸중으로인한연하장애가있는환자에서호흡기능과의연관성을밝힌연구로, 기도흡인이있는경우노력성폐활량, 1 초간강제호기량등의기능적폐용적이저하되어있음을확인하였다. 또한본연구는침상에서간단하게시행할수있는폐기능검사를통해추후기도흡인의고위험군을선별하는인자로활용하여보다빠른중재를통해기도흡인으로인한합병증을예방할수
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