- 作者： 陳台森; 葉富欽; 周毅鵬; 陳幸一
- 作者服務機構： 國防醫學院生物及生物物理學系; 中央研究院生物醫學研究所臨床醫學研究中心; 三軍總醫院外科部麻醉科
- 中文摘要： 利用Methoxyflurane先行吸入麻醉之狗進行實驗製備，在注射麻醉導引劑Ketamine之前，關掉吸入麻醉，使後者之效果減至最低。利用注射Ketamine做為麻醉之導引，可能引發心臟系統產生興奮或抑制作用，本研究之目的欲觀察不同作用與劑量、注射方式及實驗情況之關係，所謂實驗情況為比較大量出血前後之作用，大量出血為臨床之緊急情況，需要快速導引進入麻醉狀況以實行手術，而Ketamine乃常用藥劑之一，所以利用出血情況以明瞭Ketamine之利弊。在第一組動物（未開胸，僅記錄血壓及心跳），出血之前，緩慢灌注Ketamine，3種劑量（5, 10及20 mg/kg，以5 mg/kg/min分別灌注1，2及4分鐘）均引起血壓上升及心跳變快，但如果改用快速一次注射，在小劑量下產生雙相反應一先見血壓下降及心跳變慢，隨之兩者上升。心臟血管之抑制作用（血壓及心跳下降）隨劑量之變大而加重而且延長，同時嚴重發生在快速注射及出血性低血壓之情況下。其抑制作用也經常變為不可逆性以致導向死亡。進一步的研究（第二組，開胸動物）則加上測量心輸出量及動靜脈含氧差，由以上數據計算周邊血管阻力及總體供氧量。Ketamine（10 mg/kg）在2分鐘內緩慢灌注產生心輸出量及總體供氧量輕微增加，但是快速注射產生嚴重之降血壓作用，同時減低周邊血管阻力，心搏量及供氧量，此一抑制作用在出血之後更為明顯，一部份動物甚至產生嚴重而特續之低心輸出量及供氧量，最後終於死亡，本研究提供臨床使用Ketamine應注意之藥理作用以及注射方法。
- 英文摘要： Anesthetic induction with ketamine may cause cardiovascular (CV) stimulation and depression. Thestudy was conducted in dogs to evaluate the dependence of ketamine-induced CV effects upon the dosage,mode of administration and experimental hypovolemic conditions. Slow ketamine infusion (n=12) at 3dose levels (5 mg/kg/min for 1, 2 and 4 min to a total dose of 5, 10 and 20 mg/kg) consistently increasedthe arterial pressure (AP) and heart rate (HR). Rapid bolus injections at 5, 10 and 20 mg/kg (n=16)produced biphasic changes - decreases followed by increases in AP and HR. Profound depressor andbradycardic responses were readily observed with large dose, rapid bolus injection and during hemorrhagichypotension. The striking CV depression in some cases became irreversible and led to death. Furtherstudy in 8 open-chest dogs revealed that ketamine infusion (a total dose of 10 mg/kg) caused slight in-creases in cardiac output (CO) and tissue oxygen uptake (V02). However, the marked depressor responseto bolus injection was associated with decreases in CO, total peripheral resistance, stroke volume and VO . These inhibitory effects were prolonged after hemorrhagic hypotension. In a few cases, CO and VO became severely and progressively depressed and death ensued shortly following the injection.
- 中文關鍵字： ketamine; anesthetic inducton; hypotension; bradycardia; oxygen consumption; hemorrhage
- 英文關鍵字： --
