The Korean Journal of Gastrointestinal Endoscopy Room A 진정상태에서의환자의평가 김경오 한림대학교의과대학성심병원소화기내과학교실 Assessement of Patient s Status during Sedation Endoscopy Kyoung-Oh Kim, M.D. Division of Gastroenterology, Hallym University College of Medicine, Hallym University Sacred Heart Hospital, Anyang, Korea 서론내시경검사를시행받는환자는매년증가하고있는데사람들은고통없이보다수월하게검사받기를원하고있어수면내시경의빈도는점차증가하는추세이다. 수면내시경이란약물로의식의진정 (sedation) 상태를유도하여내시경을시행하는진정내시경을의미하며, 미국마취과학회의분류에의하면진정의정도에따라 4단계로구분할수 있는데 (Table 1) 1 진단목적에서시행하는대부분의진정내시경은중등도진정상태 (moderate sedation) 를유도하는의식하진정내시경 (conscious sedation endoscopy) 이나치료목적을위한내시경등일부에서는보다깊은진정 (deep sedation) 상태를유도하기도한다. 이러한진정내시경은고통없이편안하게검사를받을수있어환자의만족도가높다는장점이있으나검사받는사람의연령이나기저질환등에따라여러합병증발생의위험이있어반드시시술전합병증발생의위험도를평가해야하며, 시 Table 1. ASA Definitions of General Anesthesia and Levels of Sdation and Analgesia Moderate Minirnal sedation Deep General sedation/analgesia (anxiolysis) sedation/analgesia anesthesia (conscious sedation) Responsiveness Normal response to Purposeful* response Purposeful* response Unarousable, even with verbal stimulation to verbal or tactile following repeated or painful stimulus stimulation painful stimulation Airway Unaffected No intervention Intervention may be Intervention often required required required Spontaneous Unaffected Adequate May be inadequate Frequently inadequate ventilation Cardiovascular Unaffected Usually maintained Usually maintained May be impaired function Minimal sedation (anxiolysis) is a drug-induced state during which patients respond normally to verbal commands. Although cognitive function and coordination may be impaired, ventilatory and cardiovascular functions are unafected. Moderate sedation/analgesia (conscious sedation) is a drug-induced depression of consciousness during which patients respond purposefully* to verbal commands, either alone or accompanied by light tactile stimulation. No interventions are required to maintain a patent airway, and spontaneous ventilation is adequate. Cardiovascular function is usually maintained. Deep sedation/analgesia is a drug-induced depression of consciousness during which patients cannot be easily aroused but respond purposefully* following repeated or painful stimulation. The ability to independently maintain ventilatory function may be impaired. Patients may require assistance in maintaining a patent airway, and spontaneous ventilation may be inadequate. Cardiovascular function is usually maintained. General anesthesia is a drug-induced loss of consciousness during which patients are not arousable, even by painful stimulation. The ability to independently maintain ventilatory function is often impaired. Patients often require assistance in maintaining a patent airway, and positive pressure ventilation may be required because of depressed spontaneous ventilation or drug-induced depression of neuromuscular function. Cardiovascular function may be impaired. Because sedation is a continuum, it is not always possible to predict how an individual patient will respond. Hence, practitioners intending to produce a given level of sedation should be able to rescue patients whose level of sedation becomes deeper than initially intended. Individuals administering moderate sedation/analgesia (conscious sedation) should be able to rescue patients who enter a state of deep sedation/analgesia, while those administering deep sedation/analgesia should be able to rescue patients who enter a state of general anesthesia. *Reflex with drawal from a painful stimulus is NOT considered a purposeful response. Reprinted with permission from Gross et al. 106 The Korean Journal of Gastrointestinal Endoscopy
술중환자의상태에대해서도면밀히모니터링하고평가해야한다. 또한시술중발생할수있는여러부작용에즉각적으로대처할수있도록응급처치기구와약제등을구비해야한다 (Table 2). 진정내시경중인환자의평가는호흡, 혈압, 심박수등과같은생리적지표의감시와의식의진정정도에대한평가가모두이루어져야한다. 생리적지표 (Physiologic Parameter) 1. 동맥혈산소포화도 (Arterial oxygen saturation-pulse oxymetry) 약물에의해진정유도시가장흔히발생하는합병증중의하나가호흡기능의억제이므로진정상태인환자의호흡기능의감시와평가가매우중요한데 pulse oxymetry는동맥혈혈색소의산소포화도를지속적으로실시간측정할수있는간단한비침습적검사이며, 진정상태동안지속적인감시가요구된다. 1-3 단점은동맥혈산소분압의감소에비해산소포화도의감소는미미하기때문에호흡저하에의한의미있는동맥산소분압 Table 2. Emergency Resuscitative Equiment As sorted syringes, tourniquets, adhesive tape Intravenous access equipment including fluids Basic airway management equipment Oxygen supply Suction machine and catheter Nasal cannulae and face-masks* Bag-mask ventilation device Oral and nasal airways (all sizes) Advanced airway management equipment Laryngoscope handles and blades* Endotracheal tubes and stylets* Laryngeal mask airway* Cardiac equipment Pulse oximeter Cardiac defibrillator Emegency medications Atropine Diphenhydramine Epinephrine Ephedrine Flumazenil Glucose, 50% Hydrocortisone Lidocaine Naloxone Sodium bicarbonate *All appropriate sizes should be available. 의감소에도불구하고산소포화도는 90% 이상유지될수있어호흡저하의발견이늦어질수있다는점과또한저체온증이나저혈압, 말초혈액순환장애등이있을경우정확한산소포화도측정이어렵다는점이다. 따라서환자의호흡기능을평가하는데있어 pulse oxymetry 측정뿐아니라청진이나환자의호흡여부를눈으로직접관찰하는시진등도병행해야한다. 시술중통상적인산소의투여는그효과가입증된바없고오히려저산소증이나무호흡의발견을지연시킬수있다는보고도있어, 4-6 고연령군이나심각한동반질환이있는환자에서만시행해야한다는주장도있으나산소의투여가산소포화도감소정도를줄일수있다고알려져있어미국마취과학회및미국소화기학회모두중등도나깊은진정시산소투여를권고하고있다. 1 대개의경우산소포화도가 90% 미만으로감소하는경우를의미있는저산소증이라고보는데, 진정내시경중저산소증의빈도는 10% 내외로알려져있으며사망에이르거나기도삽관을필요로하는경우는극히드물고거의대부분약제투여를중단하고산소를공급하는등의처치로회복이된다. 7 2. Capnography Capnography 는호기말이산화탄소 (CO 2) 분압을측정하는비침습적방법으로호기시최고점을보이고흡기시최저점을보이는특징적인파형을보이며환자의호흡활동을나타내므로환자의호흡활동이억제될경우산소포화도가감소하기전에보다일찍감지가가능하다. 8-10 특히산소를투여하고있는경우 pulse oxymetry에의한호흡활동억제의감지가늦어질수있는데이러한단점을극복할수있는장점이있다. 몇몇연구들에서 capnography 를시행할경우저산소증혹은무호흡을보다조기에감지할수있다는보고가있었으나모든진정내시경에서통상적으로시행해야하는지에대해서는확실하지않다. 미국마취과학회에서는깊은진정유도시혹은중등도진정유도지만환자의호흡상태를직접적으로평가하지못할경우에시행할것을권고하고있다. 3. 심전도 (Electrocardiography) 모든건강한정상인에서항상지속적인심전도관찰이필요한지는근거가없으므로반드시해야할필요는없으며, 부정맥의발생위험성이있는심질환, 폐질환등을가진고위험군의경우시술중지속적인감시를해야한다. 1 4. 심박수및혈압 심박수와혈압은혈역동학적상태를나타내는중요한지표이므로진정전및진정상태에서심박수및혈압의변화를통 Vol. 40 (Suppl 1), 2010 (106-110) 107
해환자의상태에대한정보를얻을수있다. 예를들어시술중빈맥혹은혈압상승은진정이너무얕거나혹은잘이루어지지않은상태임을시사하며서맥이나혈압저하는과진정 (oversedation) 이유도되었을가능성이있다. 특히 propofol을진정유도제로사용하는경우혈압강하의빈도가증가하므로주의깊게감시해야한다. 진정유도전기본심박수와혈압을측정하여진정유도후변화정도를관찰해야하며시술중에는 3 5분간격으로측정하는것이권고되고있다. 수축기혈압이 90 mmhg 이하로떨어지는저혈압은 5 7% 정도에서발생하는것으로보고되고있으며생리식염수를정맥내투여하는것으로대부분회복된다. 의식의진정정도평가 (Level of Sedation) 중등도진정상태 (moderate sedation) 에서호흡부전이나저혈압등의부작용발생위험성은높지않으나진정정도가깊어질수록합병증발생의위험성이높아지므로시술도중환자의진정정도를일정하게유지하고감시하는것이매우중요하다. 하지만진정제의종류나투여방법, 환자의연령이나전신상태등에따라진정유도에대한개개인의반응이매우다양하고예측하기힘들기때문에원하는진정정도를일정하게유지하기란매우힘들며시술도중진정의깊이는연속적으로변화를보이게된다. 1. 진정평가척도 (Sedation assessement scales) 연속적으로변화하는환자의진정상태를정확히평가하고자많은노력들이있어왔으며음성명령이나물리적자극에대한반응정도에따라진정의깊이를구분한 Modified Observer s Assessement of Alertness/Sedation Scale (MOAA/S), Ramsey Sedation Scale, Richmond Agitation Sedation Scale (RASS) 등매우많은평가척도들이개발되어사용되고있으나아직까지표준화된평가척도가없어이에대한보다많은연구와개발이필요한실정이다 (Table 3, 4, 5). 11-13 현재임상연구에서 MOAA/S 방법과 Ramsey Sedation scale 이가장널리이용되고있으며특히진정내시경과관련하여서는 MOAA/S 방법이많이사용되고있는데, 미국마취과학회의분류에의한중등도진정 (moderate sedation) 은 MOAA/S score 3, 4에해당되며깊은진정 (deep sedation) 은 score 1, 2 에해당된다. 이러한진정척도 (sedation scale) 들은대개음성명령이나물리적자극에대한반응정도만을보는것으로환자의호흡기능이나심, 폐기능에대한고려가없어과연얼마나진정정도를정확하고객관적으로반영할수있을지는의문이지만임상에서비교적쉽게이용가능하다는것이가장큰장점이다. 진정내시경시술중이러한평가척도에숙달된관찰자가 3 5분간격으로계속환자의진정정도를평가해야한다. Table 3. Modified Observer s Assessement of Alertness/Sedation Scale Responsiveress Score Agitated 0 Responds readily to name spoken in 5 normal tone (alert) Lethargic response to name spoken in normal lone 4 Responds only after name is called loudly 3 and/or repeatedly Responds only after mild prodding or shaking 2 Does not respond to mild prodding or shaking 1 Does not respond to deep stimulus 0 Table 4. Ramsey Sedation Scale Level Response 1 Awake and anxious, agitated, or restless 2 Awake, cooperative, accepting ventilation, oriented, tranquil 3 Awake; responds only to commands 4 Asleep; brisk response to light glabellar tap or loud noise 5 Asleep; sluggish response to light glabellar tap or loud noise stimulus but does not respond to painful stimulus 6 Asleep; no response to light glabellar tap or loud noise Table 5. Richmond Agitation Sedation Scale Score Term Description +4 Combative Overtly combative or violent, immediate danger to staff +3 Very Pulls on or removes tubes or agitated catheters or has aggressive behavior toward staff +2 Agitated Frequent nonpurposeful movement or patient ventilator dyssynchrony +1 Restless Anxious or apprehensive but movements not aggressive or vigorous 0 Alert and calm 1 Drowsy Not fully alert, but has sustained (more than 10 seconds) awakening, with eye contact/eye opening to voice 2 Light Briefly (less than 10 seconds) awakens sedation with eye contact to voice 3 Moderate Any movement (but no eye contact) sedation to voice 4 Deep No response to voice, but any sedation movement to physical stimulation 5 Unarousable No response to voice or physical stimulation 108 The Korean Journal of Gastrointestinal Endoscopy
이상적인평가척도는쉽고빠르게시행할수있으면서관찰자간, 환자간편차가적고재현도가우수해객관적이어야하나이모든것을만족시킬수있는평가척도는아직까지없으며앞으로해결해야할숙제이다. 2. 이중분광계수 (Bispectral Index monitoring, BIS) 이중분광계수 (BIS) 는뇌파를분석하여환자의진정정도를 0 부터 100까지수치화하여실시간으로나타내는비침습적뇌기능감시방법으로주로마취과영역에서전신마취시마취심도를측정하여약물투여용량을적절하게유지하기위해많이사용되어왔으며최근에는다양한분야에서이용되고있다. 14 BIS 0은대뇌피질의활동 (cortical activity) 이전혀없는상태를의미하고 BIS 100은완전히깨어있는상태를나타내는데, 70 90이중등도진정, 60 69가깊은진정, 40 59는전신마취상태에해당되며, 진정내시경시에는 BIS 80 85가적정한수준이라는보고도있다. 14 여러연구들에의하면기존의여러평가척도들과 BIS 평가결과가모두의미있는상관관계를보여 BIS가비교적정확하고객관적인평가방법임을알수있다. 15-17 BIS는연속적으로변화하는진정의깊이를실시간으로수치화하여표시하여주기때문에환자의진정상태의변화를빠르게감지하여대처할수있다는장점이있으나진정제투여용량을줄임으로써과진정 (oversedation) 에따른합병증발생을줄이는데도움이되는지는아직확실치않아보다많은연구가필요하다. 18,19 Table 6. Adlrete Scoring Systems Respiration Able to take deep breath and cough=2 Dyspnea/shallow breathing=1 Apnea=0 Oxygen saturation S ao 2>95% on room air=2 S ao 2=90 95% on room air=1 S ao 2<90% even with supplemental O 2=0 Consciousness Fully awake=2 Arousable on calling=1 Not responding=0 Circulation BP±20 mmhg baseline=2 BP±20 50 mmhg baseline=1 BP±50 mmhg baseline=0 Activity Able to move 4 extremities=2 Able to move 2 extremities=1 Able to move 0 extremities=0 NOTE. Monitoring may be discontinued and patient discharged to home or appropriate unit when Aldrete score is 9 or greate. 진정상태에서의회복평가 (Assessement of Recovery) 진정내시경이끝난후에도환자가완전히각성상태로회복될때까지환자의의식상태, 혈압, 심박수등의혈역동학적지표및호흡기능등에대한모니터링을계속해야하는데, naloxone이나 flumazenil과같은길항제를투여한경우길항효과로인해일시적으로각성상태로회복된것처럼보이나길항제의효과지속시간이지난후재진정 (resedation) 상태가될수있기때문에 2시간이상보다오랜시간동안환자상태를모니터링해야한다. 환자가안전하게귀가할수있을정도로회복되었는지를판단하기위해여러기준들이사용되고있으며대표적인것이 Aldrete Scoring System으로호흡, 산소포화도, 의식상태, 혈압, 운동기능등 5가지항목을평가한점수를합산하여 9점이상일경우퇴원의기준이된다 (Table 6). 20 결론 진정내시경을하는가장큰이유는검사시환자의불안감이나고통을없애고편안함을제공하기위해서이다. 하지만다른모든검사와마찬가지로안정성이보장되지못한다면검사로서의가치를가지지못한다. 편안하면서도안전한검사를시행하기위해서는시술중환자의의식상태를포함하여혈역동학적상태에대한모니터링과평가가필요하다. 이를위해서는필요한장비를반드시갖추어야하고그장비를올바르게사용하고평가할수있어야하며부작용발생시적절하게대처할수있도록훈련된인력이필요하다. 참고문헌 1. Gross JB, Bailey PL, Connis RT, CJ, et al. Practice guidelines for sedation and analgesia by non-anesthesiologists. Anesthesiology 2002;96:1004-1017. 2. Council on Scientific Affairs American Medical Association. The use of pulse oxymetry during conscious sedation. JAMA 1993;270:1463-1468. 3. Warning JP, Baron, TH, Hirota WK, et al. Guidelines for conscious sedation and monitoring during gastrointestinal endoscopy. Gastrointest Endosc 2003;58:317-322. 4. Miner JR, Heegaard W, Plummer D. End-tidal carbon dioxide monitoring during procedural sedation. Acad Emerg Med 2002;9:275-280. 5. Rubin DM, Eisig S, Freeman C, Kraut RA. Effect of supplemental gases on end-tidal CO2 and oxygen saturation n patients undergoing fentanyl and midazolam outpatient Vol. 40 (Suppl 1), 2010 (106-110) 109
sedation. Anesth Prog 1997;44:1-4. 6. Downs JB. Has oxygen administration delayed appropriate respiratory care? Fallacies regarding oxygen therapy. Respir Care 2003;48:611-620. 7. Rex DK, Deenadayalu VP, Eid E, et al. Endoscopist-directed administration of propofol: a worldwide safety experience. Gastroenterol 2009;137:1220-1237. 8. Vargo JJ, Zuccaro G Jr, Dumot JA, Conwell DL, Morrow JB, Shay SS. Automated graphic assessment of respiratory activity is superior to pulse oxymetry and visual assessment for the detection of early respiratory depression during therapeutic upper endoscopy. Gastrointest Endosc 2002;55:826-831. 9. Lightdale JR, Goldmann DA, Feldman HA, Newburg AR, DiNardo JA, Fox VL. Microstream capnography improves patient monitoring during moderate sedation: a randomized, controlled trial. Pediatrics 2006;117:e1170-e1178. 10. Burton JH, Harrah JD, Germann CA, Dillon DC. Does end-tidal carbon monoxide monitoring detect respiratory events prior to current sedation monitoring practices? Acad Emerg Med 2006;13:500-504. 11. Chernik DA, Gillings D, Laine H, et al. Validity and reliability of the Observer s Assessment of Alertness/Sedation Scale: study with intravenous midazolam. J Clin Psychoparmacol 1990;10:244-251. 12. Ramsay M, Savege T, Simpson B. Controlled sedation with alphaxalone-alphadolone. BMJ 1974;2:656-659. 13. Riker RR, Picard TJ, Fraser GL. Prospective evaluation of the sedation-agitation scale for adult critically ill patients. Crit care Med 1999;27:1325-1329. 14. Roscow C, Manberg PJ. Bispectral index monitoring. Anesthesiol Clin North America 2001;19:947-966. 15. Overly FL, Wright RO, Cornnor FA, et al. Bispectral analysis during pediatric procedural sedation. Pediatr Emerg Care 2005;21:6-11. 16. McDermott NB, Vansickle T, Motas D, Friesen RH. Validation of the bispectral index monitor during conscious and deep sedation in children. Anesth Analg 2003;97:39-43. 17. Agrawal D, Feldman HA, Krauss B, Waltzman ML. Bispectral index monitoring quantifies depth of sedation and analgesia in children. Ann Emerg Med 2004;43:247-255. 18. Drake LM, Chen SC, Rex DK. Efficacy of bispectral index monitoring as an adjunct to nurse-administered propofol sedation for colonoscopy: a randomized controlled trial. Am J Gastroenterol 2006;101:2003-2007. 19. Bailey PL, Zuccaro G. Sedation for endoscopic procedures: not as simple as it seems. Am J Gastroenterol 2006;101: 2008-2010. 20. Chung F, Chan V, Ong D. A post anesthetic discharge scoring system for home readiness after ambulatory surgery. J Clin Anesth 1995;7:500-506. 110 The Korean Journal of Gastrointestinal Endoscopy