键盘乡民报到(快说我是网军!!)
我是台大胸腔内科/重症科的第五年住院医师。
网络上找不到正确的说法,就不小心认真了。
在论文第153页,Patient and method的第一二段,写道:
When a patient was accepted as a NHBD, the family consent was first obtained
after the explanation of the procedures to the family. The ECMO system (cat.
no. CB2505; Medtronic Inc., Anaheim, CA, USA), including centrifugal pump and
oxygenator, was primed with normal saline alone. The priming normal saline
was supplemented with CaCl2 up to a concentration of 1 mmol:L of calcium to
prevent acute hemodilution hypocalcemia after the donor was put on the ECMO
support. A temperature controller (11160 dual heater–cooler; Sarns:3M, Ann
Arbor, MI, USA) was connected to the ECMO to cool down the recirculating
priming solution in the ECMO circuit. The temperature set-point was 4°C.
Bilateral femoral areas were disinfected and well draped when the ECMO system
was being prepared.
After all were ready, we stopped all catecholamine infusion, and disconnected
the ventilator. Twenty-five thousand units of heparin and 10 mg of
phentolamine were injected intravenously. After the heart beats had stopped,
a strip of EKG was recorded for legal document of asystole. Then the right
femoral artery and vein were dissected and cannulated, and the cannulae were
connected to the ECMO system. [1]
这些病人,全部都是经过家属同意,才撤除呼吸器及升压剂的。呼吸器及升压剂都是维生
装置,是急救的一部份。导致病人死亡的是急救/维生装置的撤除,或者说是导致他需要
急救/维生装置背后的病因,让病人死亡的。一个人拔管、拿掉升压剂,血压掉、心跳停
是必然。而用心跳停止来宣告病人死亡,也是我们对99.9%的病人做的事。只有死因有疑
虑或如器官移植等少数案例,才需要请检察官前来。
心跳停止后,给予heparin(肝素)是叶克膜一定要用的抗凝血剂,作用是让血液与人工物
品接触的界面不要凝固。Phentolamine滴注是为了保护要取出的肾脏[2],改善他的血流
,不是降血压用(虽然他的确可以降血压)。虽然,若病人本身有出血,或他血压已经不
稳定了,用这些药的确会加速他的死亡。
然而,临床上我们常给予拔管且不重插管,又要留一口气回家的病人吗啡滴注,让病人比
较舒服一点。但吗啡引起呼吸抑制,会让病人早点走,这我们也都跟家属充份解释,家属
也都能理解。难道这样是我们杀了病人吗?同理,病人既然要遗爱人间,捐出肾脏了,在
频死前使用这些药物来增加移植成功的机率,可以说是杀人吗?
另外,文章开头就说了,死亡判定有两种,脑死或心跳停止。一般器官移植都是用脑死判
定,是因为可以在血流灌注正常的情况下等检察官来判定,再摘取器官,让器官在最好的
状态。然而如果病人肺部受伤太厉害,则临床上不允许进行脑死测试(否则会有生命危险
),则他就只能等到心跳停止,再请检察官来判定,再进行器官移稙。但检察官不可能随
传随到,因此器官长时间曝露在没有心流的环境中,造成不可逆的伤害。这篇文章说的是
如何从“心跳停止”到“等检察官来判定”到“摘取器官”的过程,利用叶克膜来保护器
官有足够的充氧血,避免受赠者好不容易等到器官了,也动了大手术移植了,后来却因为
器官的不可逆伤害,很快就衰竭(graft failure)了。
结论:
一、“为了使心脏不跳动啦/他们先注射了酚妥拉明/让血压下降 降到心脏停止”?
错,是先等心跳停止,才进行后续动作,增加成功率。死亡是撤除维生装置导致,而非医
疗团队导致病人死亡。
再说一次:
是先撤除维生装置->等心跳停止->注射药物->装叶克膜
而非注射药物->心跳停止->叶克膜
二、死亡判断分为脑死及心跳停止。这篇文章讨论的是如何在无法判定脑死的病人,在自
然心跳停止的病程中,减少器官心流不足的伤害,降低移植器官衰竭的机率,造福器官受
赠者。
1. Clin Transplant. 2000 Apr;14(2):152-6. Extracorporeal membrane oxygenation
support of donor abdominal organs in non-heart-beating donors. Ko WJ1, Chen
YS, Tsai PR, Lee PH.
2. Transplantation. 2000 Jan 15;69(1):184-6. Donor treatment with
phentolamine mesylate improves machine preservation dynamics and early renal
allograft function. Polyak MM1, Arrington BO, Kapur S, Stubenbord WT,
Kinkhabwala M.