医療倫理学 (medical ethics)

医療倫理学

Medical Ethics

医療倫理学（いりょう・りんりがく）とは、保健ケアとくに医療に関する倫理的事象（＝医療倫理）をあつかう研究分野である。医療のみならず、生物学、政治学、社会学、文化人類学、法学、哲学などのさまざまな分野と関連性をもつ、学際的な研究分野である。生命倫理学（bioethics, バイオエシックス）と医療倫理学はテーマを共有することが多いので、「基本的に同じ」と判断しても間違いではない。私は、別項で生命倫理学を次のように定義しました。「人間を対象にした治療および実験に関する倫理・道徳、ひいてはそれらに関する諸研究」（→ 出典「生命倫理学と医療人類学」）

医療倫理学は、医療倫理（リンク先はウィキペディア日本語）という歴史に先行する経験的事実と原則に依存する、すなわち先例拘束の原則（stare decisis）があるので、そのことを次に解説しよう（Weise, Mary Victoria, Medical Ethics Made Easy, 2016）。

医療倫理の4原則というものがもっとも有名である。すなわち、１）自己決定（Autonomy）、２）善行（Benevolence）、３）無加害（Nonmaleficence）、そして、４）配分上の正義（Distributive Justice）

Weise (2016)の論文にしたがってその考え方を復習してみよう。

自己決定（Autonomy）	Patients' right to self-determination emphasizes that patients are autonomous beings and have the right to make their own choices about the care they prefer to receive. This ethical principle is best exemplified in informed consent, which is decision making that involves disclosure of risks and benefits. ...	Case 01: A 57-year-old man suffers a massive stroke. The patient is in the intensive care unit, on a ventilator, and remains unresponsive. Family and friends tell hospital staff that he does not have an AD but would always say he does not want aggressive measures. Patient has a slow recovery but still suffers from dysphagia, so providers needed to make decisions on a feeding tube. Who should they speak to? Who would be the surrogate decision maker? With the patient not presenting with an AD, providers could turn to the Surrogate Act and try to discern if the patient had a spouse or adult children; if not, then ask about his parents. If parents are not alive, or not able to participate, then turn to siblings, and finally extended family or friends. This offers a way to “sift through” the crowd who is offering answers and allows staff to narrow down the correct decision maker.
		Case 02: A 55-year-old man is admitted with an active gastrointestinal bleed. The patient is a Jehovah's Witness. He is admitted with hemoglobin/hematocrit (Hgb/Hct) of 7/21 and is not responding to treatment. The Hgb/Hct drops slowly each day. Providers meet with the patient and his family each day to explain diagnosis and plan of care. Purposeful discussion occurs daily to ensure that the patient understands the risk of declining treatment. Supportive conversation occurs each day about risks and benefits. The patient continues to decline treatment and eventually becomes unresponsive. The family continues to respect the patient's wishes and allows palliative care until his death. They verbalize comfort in following his wishes in the end.
		Case 03: The Terry Schiavo case was the longest litigated case in American history, remaining in the courts from 1990 to 2005. Terry was a 26-year-old who was married about 3 years at the time of the incident. Her husband, Michael, said there were conversations during their relationship about her wishes, and she said she would not want to live “like that.” Most have times in our lives, whether it be a grandparent or loved one who is ill, or social events that raise conversations about care and what we would want or not want. As you also can imagine, her parents became upset at the idea that he wanted to stop aggressive care measures. Because she had no AD, the parents pled their case to the court to continue care. In the end, the judge ruled in her husband's favor to stop her tube feeding and allow her to die. This case raised much awareness about the Surrogate Act and gave definition to the persistent vegetative state.
善行（Benevolence）	enevolence is defined as a commitment to do good for others. It involves the concept that actions and intents have a positive effect, a positive influence, and/or produce good (optimal) patient care outcomes. It offers the belief that decisions and choices have a positive impact on lives. ...	Case 04: A 21-year-old woman currently undergoing treatment of Hodgkin's lymphoma verbalizes being distraught over chemotherapy side effects. This patient has been seen by providers numerous times throughout her treatment. They have all provided education and supportive discussion about symptom management and the anticipated response to therapy with a curative approach. Our role often as care providers is to support our patients through difficult treatment plans when we anticipate a cure, especially in a young patient.
無加害（Nonmaleficence）	Nonmaleficence involves the value to do no harm. We understand that complex care can have adverse effects or a negative impact, albeit indirect or unintentional. This value is that we do not want to ever cause harm to our patients in whatever we do....	Case 05:A 70-year-old retired lawyer has continued complaints of indigestion, dysphagia, loss of appetite, and weight loss. He goes to his primary care physician and has extensive testing over several months without symptom resolution. The patient becomes distraught over severe weight loss, pain, and an inability to diagnose. He attempts suicide by chest stabbing and is admitted to the hospital. Upon trauma testing, they find a mediastinal malignancy, which was Stage IV and inoperable. When the patient is informed of the diagnosis and prognosis, he requests hospice care. Psychiatry follows closely for capacity in decision making and finds the patient to have capacity on a consistent basis. The ethics committee is consulted early on and finds it to be in the patient's best interest and the least level of harm to him to respect his wishes and allow him to be discharged home with hospice care.
配分上の正義（Distributive Justice）	Distributive justice is how we make decisions based on the greater good or an equitable distribution of resources. Some examples may be how influenza and pneumonia vaccines are distributed to the public when supply is limited. In this instance, the health care system would prioritize children and the elderly first, as well as immunocompromised patients. Healthy adults would be last on the list to receive the vaccine(s)....	Case 06:Hurricane Katrina was one of the deadliest storms in American History. It claimed 1,836 lives with more than $150 billion in damage over 3 days in August 2005. From Friday to Sunday, August 26 to August 28, Katrina moved from a Category 2 to a Category 5 hurricane with winds in excess of 160 mph. Flood waters were reported to be 20-ft. deep. Helicopters were arriving on scene, not to pick up sick patients, but rather to drop off sick, injured, or deceased persons. Hospitals were left in utter chaos with a disaster of this caliber and temperatures exceeding 100°C. There was no running water, source, or electrical power, so equipment was not functioning. Refrigeration, toilets, diagnostic equipment, dialysis machines, and ventilators were not functioning. Supplies were very scarce, and procedures were being done using flashlight without anesthesia. .... to https://doi: 10.1097/NCM.0000000000000151
		Case 07:The Ebola virus outbreak in West Africa took frontline news with the outbreak in late 2014. The Centers for Disease Control and Prevention (CDC) website reports 13,042 cases with a mortality rate of approximately 37% (CDC, 2014). In its initial outbreak, the mortality rate was approximately 50%, with no approved treatment available. There were some therapies in clinical trials, but nothing formally approved at the time of the outbreak. Experimental therapies were pulled from studies with no known effects ... just being offered as a hope of treatment. There were a limited number of doses available, so the CDC had to determine who would get the doses. They started by treating the health care workers, in hopes of keeping them alive to take care of the sick. Over time, and as they learned the cause of the spread of the virus, they were able to reduce the mortality rate to approximately 37%.
		Case 08:A 42-year-old mother of three children is on the waiting list for solid organ transplantation. The patient is relatively healthy, with few comorbidities. Also on the list is a 67-year-old man, a father and a retired teacher. He has comorbidities of heart disease and chronic obstructive pulmonary disease. We would apply the “fair life” theory that offers the younger of the two at chance of a fair life. One could make this waiting list more complex by adding a 17-year-old, or a person of high social stature or celebrity. The transplant field has seen the “Mickey Mantle” effect when a person of distinguished stature is on the waiting list as well. Society tends to offer a value to one who has earned such distinction, which can complicate the decision on picking the donor.
		all cases are cited from https://doi: 10.1097/NCM.0000000000000151

今日では、１）自己決定（Autonomy）、２）善行（Benevolence）、３）無加害（Nonmaleficence）、４）配分上の正義（Distributive Justice）に加えて以下のようなものが指摘されている。

５）人権の尊重（Respect for human rights）、６）治療者と患者のあいだの連帯（Solidarity）、そして、７）医療をおこなう上で遭遇するあいまいなものを受け入れる態度（Acceptance of Ambiguity in Medicine）である。ょ

医療倫理は、これらのことをただ守っていればよいというものではない。実際の医療の遂行には、上掲の原則の適用する際に矛盾となる事例が数多く存在する。２つの事例（ジレンマ）をあげてみよう。

１．自己決定＝自律性と無加害／加害の原則の衝突

自己決定は、文化の違いにおいて最大限尊重される社会とそうでない社会との間に、さまざまな広がりをもつ。また、患者の治療選択おいて、家族や親族が介入し、本人の希望や思いと衝突することがある。これらの場合の自己決定は形骸化したり、また不本意な形で決められて、自律性の原則が理想的には適用されないことがある。また、自己決定が阻害されることが、周囲のものからの患者当人への加害という現象を引き起こすこともある。後者の場合は、医療者は無加害の原則を貫くことが可能であるが、患者にはその選択が苦痛＝加害になることすらある。西洋合理主義の自己決定＝自律の原則が虚構ないしはある文化や時代の社会的構築物であるという批判も当然ある。

２．安楽死（安楽殺、Euthanasia）

不治の病、取り除けない想像を絶する苦痛状態、あるいは終末期ちかくにおける、事前の書面による契約にもとづいて、医師が過剰の鎮静剤を投与したり、苦痛を除いた上での人工呼吸器の停止など、死期の前倒の施行（つまり善意による殺人）を安楽死という。安楽死は、患者が望む善行と無加害の原則が矛盾する典型的なケースである。多くの社会は、安楽死を認めていない。ただし、安楽死の実行の免責（＝殺人行為の違法性阻却）が、司法権力による事前の許可により可能になることもあり、その場合は、無加害の原則よりも患者が望む善行を優先しているとみなされている。

安楽死が一定の手続きを通して認められている社会や国家においても、それらの国々においても宗教や自分自身の信条にもとづいて選択しない人を優先するために、オプトインしない限り安楽死選択というものはない。

さて、医療倫理学が、生命倫理学（bioethics, バイオエシックス）と対比されて論じられる場合、前者を専門的な医療専門家が取り扱う倫理、後者がより包括的で一般的な問題を取り扱うかのような取り上げられかたをするが、これには留意が必要である。なぜなら、医療の専門家——とくに生物医学や臨床医学——が、上記の隣接科学から接近する倫理学的アプローチをしばしば生命倫理学として、医療倫理学を狭い意味での臨床医学の支配的言説で領域を確定し、隣接領域の専門家の排除しようとする傾向が［その多くが例外だが］全くないとは言えない。

医療倫理学が取り扱っている事象は以下のようなものがある。

１．生命の始まりや出産にかかわる健康（リプロダクティブ・ヘルス）の問題

着床前の診断（Preimplantation genetic diagnosis, PGD）、出生前の診断、人工授精、性別生み分け、人工妊娠中絶、減数手術、

【出産・中絶・自己決定権】女の身体は長く出産・中絶・自己決定権をめぐって論争の渦中におかれてきた。男の身体に対して女の身体はおしなべて文化や社会のなかで管理対象にされ、時に祝福されることもあるが多くは監視制限され時にはタブー視されてきた。つまり、初潮・月経・妊娠・出産・育児そして閉経までのライフサイクル(生活史)は、あくまでも自然なものであり、男よりも自由度が少なく、しばしば劣等視され、女の身体は長く管理対象になってきた。出産のための女の身体は男の医師や研究者により研究対象にされ、女のマスターベーションは男のそれよりも危険視された。その理由は近代産科学が出産のために女の身体は管理されなければならないということに根ざしていた。そのため人工妊娠中絶が女の自己決定のための権利であるという主張がなされた時、家父長制を是とする社会はその女性の権利を生命の尊厳(pro-life)に対する挑戦であると受け止めた。そして自己決定権を主張する女たちを中絶を選択する権利（pro-choice）の主張だと決めつけたが、これは女の身体は女による自己決定権があり、それは男性のそれと同等にせよという彼女たちの真の要求を適切に表現するものではない（→「ジェンダー」）。

２．遺伝子診断

遺伝カウンセリング、ＤＮＡ鑑定、心理学的・法学的・倫理的問題

３．脳死と臓器移植

臓器の収穫と分配、テクノロジーと倫理、臓器の商品化、バイオポリティクス

４．終末期医療

終末期ケア、安楽死（尊厳死）、認知症（→老年学）、死生学

５．人体を対象とする臨床試験

ヒト胚研究、インフォームド・コンセント（情報を与えられた上での合意／非合意）、ニュルンベルク・コード、

６．優生学

優生思想・優生学.

人種主義

７．基礎研究