Doctor’s Rules of Decision-Making

By Bo Shining

People often encounter problems while making decisions:incomplete information,inadequate time,and intimidating,life-or-death consequences may influence their decisions.

These types of problems are especially commonplace in hospitals.

Doctors can never wait until they have all the information about the disease before diagnosis and treatment.Instead,they have to decide on a treatment within a short period of time.Therefore,only those who can make quick decisions on the basis of limited information can be regarded as qualified doctors.This ability is not easy to come by;it stems from one’s analytical skills and clinical experience,both of which can only be acquired over time.

When it comes to analytical skills,doctors usually follow four rules in their decision-making while processing incomplete information.

Rule Number 1:The Law of Tang Sanzang (a master monk in the 16th century novel Journey to the West)

On their journey to the West,Tang Sanzang was often captured by demons and monsters.In most cases,his three disciples didn’t know what superpower the captor had or who they were.As long as Tang Sanzang was alive,Monkey King would find a way to rescue him;when Monkey King’s powers failed,he could turn to Guan Yin (Chinese translation of the Avalokite?vara) for help;when Guan Yin was powerless,there was still Tathagata who could offer help.So long as Tang Sanzang was alive,there was surely a way.Similarly,in hospitals,as long as the patient is alive,there is hope.This is the Law of Tang Sanzang.

For example,I have had many patients in the ICU suffering from cardiac arrest,which could be caused by a number of things.However,in those few golden minutes when the patient’s life is at stake,the most important thing is not looking for the cause of cardiac arrest,but keeping them alive.Therefore,I focus on three critical indicators in the patient:heart rate,blood pressure,and respiration.If the patient’s heartbeat is unstable,I use medicine to keep it stable to avoid fatal arrhythmia;if the patient’s blood pressure is low,I use medicine to raise it to ensure that every organ is getting blood flow;if the patient has breathing problems,I immediately have the patient’s trachea intubated with a ventilator so as to provide them enough oxygen.

我們在做決策時，經常會遇到一些問題：首先，需要的輔助決策的信息不全面；其次，留給決策的時間往往有限；最后，決策帶來的后果時常性命攸關。

在醫院里，這種問題尤為常見。

醫生永遠都不可能等掌握了疾病的全部信息后再開始診斷和治療，而必須在短時間內決定治療方案。所以，只有具備了在信息不完備的情況下快速決策的能力，才算合格的醫生，但具備這種能力非常不容易，因為它是建立在長期養成的思維邏輯和大量臨床經驗的基礎上的。

思維邏輯方面，醫生在信息不完備的情況下做決策，會遵循下面四條法則。

第一條：唐僧法則

在西天取經的路上，唐僧經常會被妖怪抓走。大多數情況下，他的幾個徒弟都不知道這個妖怪有什么法力，是什么來頭。但是只要唐僧不死，孫悟空就總有辦法把他救回來。就算孫悟空救不了，還可以求助觀世音；觀世音不行，還有如來。所以只要唐僧活著，就有辦法。

同樣的道理，在醫學上，只要先保證病人活著，就有希望。這就是唐僧法則。

比如，在ICU，我經常會遇到心搏驟停的病人，原因可能有無數個，但是，在病人生死攸關的那幾分鐘里，尋找心跳停止的原因不是最重要的，最重要的是先救命。所以，我最先關注的一定是病人的三個指標：心律、血壓和呼吸。心律不穩，就用藥物把心律維持在一個穩定的水平，處理致命性的心律失常；血壓低，就用升壓藥物把血壓升起來，從而保證身體每個器官都有血流；呼吸出現問題，就立刻對病人進行氣管插管，用呼吸機幫助病人通氣，給病人提供人體必需的氧氣。這樣，病人的命就保住了。

唐僧法則是醫生做決策時的第一法則，也可以把它稱為生命第一法則。這條法則的核心就是先把緊急事件轉化為常規事件，從而給病人爭取更多的時間，然后做進一步的判斷和處理。

第二條：第一張骨牌法則

唐僧活下來了，但妖怪尚存，不解決，唐僧還是會遇到重重危機。這就要用到醫生決策時的第二個法則：第一張骨牌法則。

The Law of Tang Sanzang is the first law doctors follow while making decisions.It can also be named the first law of life,which aims to buy the patient more time for further treatments.

Rule Number 2:The Domino Effect

Tang Sanzang has survived,but the monsters are still there.Unless the monsters are all killed,Tang Sanzang’s life is still in danger.Here is where the Domino Effect comes into play:when you push the first tile,all the tiles behind will fall one by one,for it is an interconnected system.Correspondingly,in the medical field,a patient’s symptoms are like fallen domino tiles laid in front of doctors,among which hides the most critical cause which leads to the relevant symptoms.

So the Domino Effect means that no matter how complicated the patient’s condition might look at first sight,we have to locate the first domino tile:the disease which explains all the symptoms.As a result,we can find the most effective treatment.This law is also referred to as the law of minimalism.

I once did a consultation session for an old lady in Urumqi City,who was in her 80s and was diagnosed with lung cancer and thyroid cancer a year ago.In addition,she suffered from pneumonia,breathing difficulties,bone pain,osteoporosis,bone spurs,and lumbar disc herniation.The patient was so depressed that she couldn’t stop sobbing and never slept.

Confronted with so many diseases and symptoms,what should I do? Which disease was the most critical one—the first domino tile?

I thought the first domino tile was lung cancer,which could explain the patient’s other symptoms.Lung cancer blocked the trachea,causing pneumonia,which then led to breathing difficulties;bone metastasis of lung cancer could cause severe bone pain,which gave the patient further problems like insomnia and depression.As for the other symptoms,they were all combined underlying diseases.

Therefore,I tested the blood circulation and tumor genes,which eventually located a specific lung cancer gene in her blood.Based on this result,I applied targeted therapy for lung cancer.Two weeks later,all her symptoms were relieved,which bought time for her follow-up treatment.

This rule might sound easy,but it is difficult to find the first domino tile in a pile of blocks.To find the first one,we need to know the third rule:the Sound of Hoofbeats.

Rule Number 3:The Sound of Hoofbeats

你或許玩過多米諾骨牌——只要推倒第一張骨牌，其他所有的骨牌都會相繼倒下，它是一個相互聯系的系統。相應地，在醫學中，病人身上的各種不同癥狀就像是擺在醫生面前的一張張倒下的多米諾骨牌，一定有一個最關鍵的原發病因導致了這些癥狀相繼出現。

第一張骨牌法則就是，在診斷中，無論病人的病情有多么復雜，能用一種疾病解釋病人出現的所有癥狀，就不考慮太多其他疾??；能用一種治療方法給病人醫治，就盡量避免所謂的面面俱到。這一法則通常也被稱為簡約法則。

我曾到烏魯木齊給一位80 多歲的老太太會診。她一年之前被診斷為肺癌、甲狀腺癌。此外，她患有肺炎，呼吸困難，還伴有骨頭疼、骨質疏松、骨刺、腰椎間盤突出等問題。她經常情緒低落，會不停地掉眼淚，整晚整晚睡不著覺。

這么多的疾病和癥狀就像擺在我面前的一張張多米諾骨牌。該怎么辦呢？哪個病才是最關鍵的第一張骨牌呢？

我的判斷是肺癌，因為它可以解釋病人的所有癥狀。肺癌阻塞氣管就會引起肺炎，肺炎會引起病人呼吸困難；肺癌骨轉移，就會引起劇烈的骨痛，病人也會因為疼痛而失眠、抑郁。至于其他癥狀，都是合并存在的基礎疾病。

所以，我讓這位老人進行血液循環腫瘤基因的協測，終于在血液里找到特異性的肺癌基因。根據這個結果，我對她用了靶向性肺癌治療藥物。兩周后，她所有的癥狀都得到緩解，為她的后續治療贏得了時間。

這個法則聽起來似乎并不難，但是想從一堆倒下的骨牌中找到第一張骨牌就不太容易了。想要找到第一張骨牌，就需要用到第三個法則：馬蹄聲法則。

第三條：馬蹄聲法則

醫學院的老師經常會告訴學生們一句話：“如果你聽到馬蹄聲，先想馬，不要猜是什么馬?！瘪R蹄聲法則說的其實是概率問題。醫生決策時，要優先考慮大概率的常見病、多發病，根據概率大小，逐一落實，最后再考慮罕見病。

強調這個法則是因為人有慣性思維，而且對罕見的東西會有比較深的印象。一旦一個醫生近期診斷或者接觸過患有罕見病的病人，他就很容易產生思維定式。一旦出現思維定式，在以后的工作中遇到類似癥狀的時候，他就容易過高估計罕見病的可能性，從而忽略了常見病。

比如，咳嗽是一個常見的癥狀，引起咳嗽的原因很多，其中一種罕見情況是血管炎。如果醫生近期見到過血管炎引起咳嗽的病例，那么下次再遇到咳嗽的病人，他就很容易先考慮血管炎，而忘記了這是罕見情況，應該放到最后考慮。正常情況下，醫生應該優先考慮的病因是呼吸道感染、肺炎、氣管炎；如果對方是老年病人，還要警惕是不是腫瘤原因；如果病人服用高血壓藥物，還要考慮是不是藥物副作用原因。

所以馬蹄聲法則是為了避免主觀偏差。

那么，是不是按照上述法則就可以完全避免醫學的不確定性而快速做出正確決策了呢？不是。

Teachers in medical school often tell their students:When you hear the sound of hoofbeats,think of horses,not zebras.This rule is about probability.While making decisions,doctors should give priority to common and frequently-occurring diseases which have a higher probability,and consider rare diseases at the end.

This rule is emphasized because people tend to have a stereotyped way of thinking and usually have a deeper impression of rarer things.When a doctor has recently diagnosed a patient with a rare disease,they can easily develop a mindset of overestimating the possibility of rare diseases while encountering similar symptoms in new patients,thereby ignoring common diseases.

For example,coughing is a common symptom caused by many illnesses.One of the rare causes is vasculitis.If the doctor has seen a case of vasculitiscaused coughing lately,they could easily consider vasculitis first when encountering another coughing patient,forgetting that this is a rare case and should be considered lastly.Under normal circumstances,the causes doctors should give priority to are respiratory infections,pneumonia,and bronchitis.If the patient is elderly,the possibility of a tumor should be taken into account;if the patient is taking medicine,the side effect of the medicine should be checked.

So the law of hoofbeats is there to avoid subjective bias in diagnosis.

The three rules mentioned can only reduce the probability of making errors,but uncertainty still occurs frequently.According to statistics,even in Western countries where medicine is highly developed,the rate of misdiagnosis in emergency rooms is still as high as 10%-20%,and the rate of missed diagnosis can be as high as 25%.Why is that? Because even if those rules are followed,our subjective experiences still render deviations in our decisionmaking while facing uncertainty and urgency.

Rule Number 4:The Principle of Golf

The Principle of Golf is used to correct our subjective deviations.

In order to get the ball into the hole,golfers constantly adjust their stance and swinging angles.The same goes for doctors.From the very beginning,doctors need to adjust and readjust their judgments as well.

When a patient is first admitted to hospital,the admission diagnosis is the doctor’s initial decision.After hospitalization,the patient goes through further examinations,consultations,and treatments,on the basis of which the doctor can adjust and correct their initial decision with more information.When the patient is cured and discharged,the doctor can give a discharge diagnosis,which,in most cases,is not exactly the same as the admission diagnosis.

There are many methods doctors use in adjusting their decisions,such as the evidencebased approach,multidisciplinary treatment,or inviting experts of a certain field in other hospitals for collective consultation,so as to avoid errors caused by personal experience.All of these practices aim to avoid biases brought by one doctor’s personal subjective experience.

In the field of medicine,maintaining principles can help when confronting complex issues.Grasping these four rules can help us make better decisions in our daily life.

(FromLectures on General Medical Knowledge by Bo Shining,CITIC Press.Translation:Lu Qiongyao)

上述三個法則只能降低發生錯誤的概率，而不確定性還是會經常發生。據統計，即使是在醫學高度發達的西方國家，急診誤診率仍然高達10%～20%，漏診率甚至高達25%。為什么呢？因為即使遵守了法則，面對巨大的不確定性和緊迫性，在快速決策的過程中，主觀經驗還是會帶來偏差。

第四條：高爾夫法則

高爾夫法則就是用于糾正醫生的主觀偏差的。

打高爾夫的人為了讓球最終進洞，會不斷調整自己站立的位置和揮桿的角度。醫生也一樣，從最開始決策時，就需要不斷校正自己的判斷。

病人入院時有入院診斷，入院診斷就是醫生最初給的決策。病人住院后，經過進一步檢查、會診、治療，醫生會根據這些信息對最初的決策進行校正。等到病人痊愈出院，醫生還會給出出院診斷。大多數情況下，入院診斷和出院診斷并不完全一致。

醫生在校正決策的過程中會用到很多方法，比如運用循證醫學的方法尋找決策的最可靠的證據，比如組織多科室會診避免個人經驗帶來的錯誤，比如邀請國內某個領域的專家會診……這些都是為了避免醫生個人主觀經驗帶來的偏差。

在醫學的復雜性面前，靈活帶來的優勢越來越小，原則帶來的優勢越來越大。掌握這四條法則，會為你在日常生活中的決策提供幫助。

（摘自《薄世寧醫學通識講義》中信出版社）