29 Oct 2009


I gave a talk at a Chinese national meeting in October. The meeting was very well organized, and we are indeed experiencing tremendous progress in the quality of research in China. On the spot, I was also invited to chair a free paper session.

In a free paper session of scientific meetings, investigators present their work concisely followed by some discussion. In most meetings, the job of a chairman is very light. One only needs to read the title of the talk, and ask whether the audience has any questions or comments after the presentation. If no one speaks up, you just call for the next presenter (though most responsible chairmen would make up some questions themselves, i.e. pretend to be interested).

In China, the situation is different. I learned that a chairman had to summarize the presentation and comment on the quality of the work. This created some difficulties for me. Since I learned most of my medicine and basic science in English and the presentations were in Chinese, I had to guess if they were talking about stuffs like 'endoplasmic reticulum stress' and 'tumor necrosis factor'.

I was initially quite puzzled by this practice. What is the point of summarizing the presentation when the presenter has just done so? On second thoughts, this may not be a bad idea.

First, if a talk is lousy, at least one person has to remain awake and listen intently. Otherwise, how can he summarize the work?

Second, the summary by a chairman represents things that even an outsider can understand. These should be more important and noteworthy. In fact, I often discourage students from copying notes during my tutorials so that they may retain what is really important.

Finally, it is reassuring to see that the chairman does know something about a topic. This reflects the quality of the whole meeting.

As for the comments, I conveniently used terms like 'impressive', 'important', 'innovative' and 'intriguing'. Sometimes I mean it, but sometimes I was playing Sir Humphrey Appleby.

22 Oct 2009


Last month, we attended a scientific meeting in Taipei. My mentor was delighted when the work of our research assistant was chosen for oral presentation.

Since she was not a doctor by training and had never presented in such kind of meetings, the little girl was understandably terrified. We had to persuade and reassure her again and again before she agreed to present – at a price. As promised, we gave her training and rehearsals, and ran through her presentation slides repeatedly. At one session, she made me do the presentation and videotaped my performance.

This reminded me of my first presentation in Madrid. It is indeed scary when you think most of the audience are more knowledgeable than you and may make unexpected criticisms. However, my mentor taught me much about presenting a scientific work which I still find useful now. Most of the essentials are covered by books on speeches. Let me just highlight the more practical ones.

1. Do not read the title of your talk. The chairman would have done this during the introduction.
2. Put fewer words in the slides. Do not put things that you are not going to say. Otherwise, the audience would be busy reading the slides and ignore what you say.
3. The title of a slide reminds you what to say. Choose the words carefully.
4. Present the aims of the study clearly and deliver the answer point-by-point in the last conclusion slide. This indicates a clear mind.
5. The ‘thank you’ slide is useless. Say 'thank you' instead and stop at the last conclusion slide. Then the audience can digest the message and ask relevant questions.

So what happened in the end? Before the chairman could introduce her, the little girl ran up the stage, said 'thank you, chairman' (for what?), and began the well prepared presentation. Afterwards, the chairman asked two questions we had already prepared. We saw a confident smile and knew she was safe.

15 Oct 2009


I spent the better half of last week updating my CV. The impressiveness and innovativeness of the computer input system have been elaborated extensively elsewhere (see http://ccszeto.blogspot.com/2009/10/obotchaman.html) and will not be the focus of this article. Instead, I want to talk about my CV.

I prepared my first CV when I applied for a resident post in my current department. KL was responsible for screening the applications then. Soon after I sent out my CV, I was summoned to his office.

“How can I recommend you for an interview if your CV only contains your name?” he asked.

“No, I thought I wrote many things. See, my employment record is here.”

“Where are your scholarships and subject prizes?”

“Oh, I did not keep any record and do not like to boast about those things.”

At this point, KL was completely fed up. He threw a document at me and said, “Copy it. Find whatever applies to you.” I turned the cover. My goodness! That was the CV of the Walking Harrison when he was an intern. Till now, my record of scholarships remains inaccurate. Luckily, this section is no longer important as I grow older, and I finally swiped it off from my CV.

Did I learn anything?

Last week, I was appalled when I found out that the University wanted the record of my conference abstracts, outside talks and services. Even if I remembered everything I did, how could I recall when I did it? I searched my pocket PC, only to find that old records in the calendar were automatically erased.

As usual, I mentioned my difficulty to my mentor. History repeats itself. That afternoon, I received his own CV.

8 Oct 2009


You may not be sympathetic for what I described last week. Can I not predict the severity of gastrointestinal bleeding based on the clinical data provided, and thus reject some cases of urgent endoscopy?

Yes and no. There is indeed no shortage of prediction scores (of anything) in the literature. How they may help depends on the setting and application.

In a study published earlier this year, the Glasgow-Blatchford bleeding score (GBS) was validated in 4 UK hospitals.[Stanley AJ et al. Lancet 2009;373:42-7] The overall accuracy of GBS to predict the need for endoscopic intervention and death among patients with symptoms of gastrointestinal bleeding was good, with an area under ROC curve of 0.90. The investigators also prospectively implemented the score in real clinical practice and demonstrated that the need for hospitalization decreased.

Can I apply it? When one looks at GBS carefully, the low risk criteria include normal serum urea, normal hemoglobin level, normal blood pressure and heart rate, and absence of melena, syncope, cardiac failure, or liver disease. If a patient has none of these, you really would wonder if he/she suffers from anything at all. In fact, in the validation study, 56% of the patients fulfilling the low risk criteria (GBS=0) had no lesion or just hiatus hernia on endoscopy. It looks as if the score is most useful in helping those who cannot clerk a proper history and make the diagnosis of upper gastrointestinal bleeding. Sadly, whenever I am consulted, the patients would have at least several of the risk factors. According to evidence-based medicine, I should have no choice but come back to the hospital every time.

Another factor we cannot ignore is that the negative predictive value of any test depends on the prevalence of disease. At the primary care clinic or emergency department where most patients with symptoms of gastrointestinal bleeding actually would not die or require endoscopic therapy, using GBS to rule out significant bleeding is safe and accurate. Managing old and frail in-patients is obviously another ball game.

1 Oct 2009


My colleagues often consider me unlucky on call days. As an on-call gastroenterologist, I have to get back to the hospital in the middle of the night if a patient requires urgent endoscopy. Suffice to say, my hit rate is consistently above 50%, while many colleagues hardly ever come back. The difference cannot be explained by chance alone.

On the last on-call day before my overseas training, I had so many cases at night that the patients and their accompanying nurses had to line up in the waiting area, much like what it would be in a busy morning session. I also used up all the endoscopes in the cupboard and had to cleanse (I confess – I did not know the proper disinfection procedures) and reuse them myself. Last week, I also entered the endoscopy unit after office hours for three consecutive days.

I do not strongly believe in the play of luck. There must be a reason.

First, I thought there was recall bias. My colleagues were underreporting and I was just whining. However, after over 50 person-years of prospective follow-up, there was indeed a pattern.

Second, I hypothesized that my colleagues actually received as many calls as I did, just that they would turn down the requests. In other words, the difference should be apparent by composite end point analysis. LL and DS disagreed and said they really slept through the night. Of course, I can never confirm this.

My latest view is the presence of confounding. For borderline cases, people are ready to call me because they know I would say yes. When I was young, I was too shy to refuse. Now that I am older, I have become so used to coming back that I no longer bother to refuse. To test this possibility, we can blind the hospital staff to the call list.

Last Sunday, my Boss gave an excellent lecture in Taiwan entitled “Is emergency endoscopy necessary?” To this, KL had a wonderful idea. We can conduct a prospective study. When physicians are on-call, the best supportive care will be provided. When surgeons are on-call, emergency endoscopy will be performed at every request. Yes, this would be ground breaking.