Occam’s razor

Occam’s razor (or the law of parsimony) is a problem-solving principle attributed to William of Ockham (c. 1287–1347), who was an English Franciscan friar, scholastic philosopher and theologian. The principle states: ‘other things being equal, simpler explanations are generally better than more complex ones’. This month’s blog looks at simple interventions and principles, and whether Occam’s razor hold true in our practice.

Paracetamol – great drug, right? I swear by it, and dispense it liberally, both at home and in the operating theatre and the intensive care unit. A simple study with a very simple hypothesis is published in October’s edition of the journal, comparing oral (enteral) with intravenous (parenteral) paracetamol in ICU patients. Patients who received the intravenous formulation were much more likely to suffer hypotension and require vasoconstrictors to ameliorate this. Wow – so paracetamol is not as harmless as we all think? If one off doses can cause hypotension like this should we still be giving it at all in our ICU patients, or should we only be giving it enterally (presumably via the NG tube – hypotension still occurred but less commonly)? Maybe this simple, effective drug is not the panacea? A very interesting study I am sure you will agree.

What about teaching tracheal intubation to novices? We have traditionally taught the use of the Macintosh laryngoscope first, but will they learn it and remember it better if they are taught with a videolaryngoscope? Actually, perhaps not – this excellent study studied a group of medical students and looked at skill retention. This study showed that the students learnt how to use the Macintosh, A.P. Advance™, C-MAC® and Airtraq® laryngoscopes equally well at first, but one month later, they seemed to have retained the skill-set required for laryngoscopy significantly better with the Macintosh and Airtraq laryngoscopes. In this instance, simpler seems to be easier to pick up again and get to grips with more quickly, a salutary lesson.

This month, we also publish an interesting systematic review of the effect of propofol compared with inhalational anaesthesia on postoperative outcomes including pain. This well-conducted rigorous review found that patients who received total intravenous anaesthesia with propofol did indeed have reduced pain scores 24 hours after surgery, although the effect size was quite small. But, it also confirmed that postoperative nausea and vomiting was markedly less common. Is this enough to make you switch your technique to TIVA? Maybe not, after all these are not really important outcomes like mortality, but will we ever recruit enough patients to see a difference in mortality if there was one – I doubt it. So what are we waiting for, or do we just not believe there is actually a difference? Perhaps it is simpler to believe the opposite, that inhalational and propofol are much of a muchness for maintenance of anaesthesia and we are not convinced either way yet.

Finally, our statistics article explains why odds and risks (and other numbers) often confuse things, both for researchers and for readers (consumers). Why do we like to use complicated statistics to describe things, when simpler explanations are often possible if not preferable? If you, like me, don’t know the difference between the odds of something and the risk of the same thing, then read it and learn – I did, and I am off to put a bet on the 2-30 at Newmarket…

 

Andrew Klein

Editor-in-Chief

Advertisements

Leave a Reply

Please log in using one of these methods to post your comment:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s