Saturday, 5 January 2013

Legal vs Moral Duty of Care

If a doctor is driving past the scene of an accident, do they have an obligation to stop and help?

According to the law in the UK, no. Duty of care only applies where you have actually created the situation through which someone may get hurt. An example of this is driving: the driver has a duty of care to the other road users not to let them come to harm as a result of their actions.

If the doctor chooses to ignore someone who is hurt, then it is called a 'pure omission', and they are not doing anything wrong in the eyes of the law. Similarly, the GMC does not list anything about treating people who are not your patients in the "duties of a doctor"; however, doctors "also have a duty to the health of the wider community", according to the section on responsibilities from the same website. The use of the word community seems to imply that this doesn't apply to harmed individuals, but rather the potential for harm to come to other people.

And yet, if you use the ethical framework I outlined a while ago, it always seems moral to go and help someone in distress (with the exception of the fact that it may not give them much autonomy; however the other 3 principles override that in this case). So while you have no obligation to do it legally, it is the right thing to do. Does that mean you have a moral obligation? I would argue that you do, on the grounds that you are faced with two options: help, or leave. One is morally correct, and the other is wrong. Therefore, anyone who can help should help, regardless of what the law says. 

If and when someone does go and help to treat a person who has been injured, it could then be argued that the injured person is a patient, and if anything goes wrong while their rescuer is helping them, it can legally be blamed on the rescuer, even though without them, they might have been in an even worse state. 

So it's tricky: help someone in need and face recriminations if you don't get it right, or leave them alone and wait for someone who has a contractual obligation (paramedics, etc). So far, I've never been in a situation like that, but I hope that when the time comes, I'll be able to recognise my skill set without bias and do the right thing.

Sunday, 25 November 2012

The Mind Reader

Recently on the BBC was a program called "The Mind Reader". It followed the families of several patients with brain injuries that had left them without control of their muscles or speech centres; although in every case they clearly loved and cared for their children very much, it was impossible for them to know how much they understood.

Each family coped with this in a slightly different way - one explained to their son who he was every time they saw him, another tried to discern if their son could respond through his thumbs and eyes, and a third talked to theirs like they would talk to anyone, regardless of whether he understood or not. This uncertainty was one of the things that struck me the most about the lives of the families - no one could help them find out whether their affection was falling on deaf ears, and if anyone could, would they want to know? 

Finding out if these patients are conscious has big implications for everyone involved. Their carers and families, if they are not aware of their surroundings, could feel as if they have been wasting their time and their love. Are they still human if they cannot experience human emotion, cannot perceive anything? This is not a question to be answered with a simple yes or no. Similarly, if the person is conscious, but cannot communicate to those people who they love and are loved by, what can be done to improve their lives? Is it easier for the family to know whether or not they can understand, or is ignorance truly bliss?
A scientist called Professor Owen, who has worked on various issues surrounding consciousness in the past, has devised a way of discerning whether a person is capable of responding to questions. Using an fMRI scanner, he monitors their brain activity and asks them to imagine certain scenarios. Humans use the same areas of the brain to imagine doing something as they do when they are actually doing something, and so by imagining different things, you can produce distinctly separate brain activity patterns. The two things Prof. Owen asked the patients to imagine were playing tennis and walking around their house. 

Not all of the patients in the group shadowed by the BBC appeared to be conscious. One person in particular did not respond at all when asked to imagine playing tennis in the fMRI scanner. The parents were incredibly gracious about it, and while they were thankful to the doctors for providing them with answers, they were left with the conundrum of how to carry on. Leaving their son seems barbaric, and I don't think any of the families in the program even considered that as an option; at the same time, carrying on when there is very little chance of it having an effect must be very, very difficult. But carry on they did, and even if it was not received, I think the parents were comforted by still having their son anyway - talking helped them more than anyone else.

However, some people could respond to Prof. Owen's stimuli. Seeing the reactions on the faces of the friends and family of those patients was amazing, and reminded me of why I want to become a doctor, for moments like that, where you can make such a profound difference to someone's life through research and treatment. Having established that they could respond, the professor asked them a few questions to find out how much of their world they were aware of. One person, Scott Routley, who had been considered unresponsive for 12 years following an accident, answered yes/no questions through imagining different things, conveying that he remembered events from before and after the accident. The next question they asked Scott was whether he was in pain. This question is central to the care of patients in PVS - if they are conscious, unable to respond, and in constant pain, is it really more kind to continue caring for them? If the answer was yes, and he was in pain, Scott was asked to imagine playing tennis. If the answer was no, when prompted, he would imagine walking around his house. 
Professor Owen asked the question. A prerecorded voice chimes in: "imagine" - the prompt for Scott to respond. The virtual model of his brain flashes red in the upper right of the screen. He has imagined walking around his house. 

It's important to remember that not all PVS patients are conscious: in Prof. Owen's experience so far, "about 20% appear to be". However, just being able to answer simple questions is the first step down a road towards communicating with people who have no other way, who are locked in but can't tell anyone. Hopefully the technology can be used to better their care and treatment by giving the doctors, nurses and family members who look after them some feedback on what they want.

Sunday, 28 October 2012

Bond Chemistry

Today, I watched Skyfall, the new Bond film. It's a fantastic film, with gorgeous actors, actresses, cars and explosions abound. I would do a post critiquing it and examining the themes throughout, but that's not what this blog is for, and it'd just be a drop in the online ocean of fan-made reviews of films they've just seen.

So instead, I thought I'd look into the sciencey medically bit that intrigued me. The main villain is revealed to have bitten a cyanide pill in the past, which failed to kill him; he now has very few teeth and  has to wear a false set. When he takes them off, the muscles in his face seem to sag, and the lower half of his eyeball is revealed, as if someone had pulled down on the skin around his cheek, seemingly because his dentures also include supports for his maxilla or something.

But what I thought I knew about cyanide was that it works by inhibition of one of the enzymes used in respiration. Could it really eat away at the inside of your mouth? The first clue was in the name of the actual chemical inside cyanide pills, hydrogen cyanide. This tells you that it is a compound of the formula HX, where X is some negative ion (here, it is cyanide). These kind of compounds dissociate in solution to form H+ ions and X- ions. They're also known as acids. In this case, the "X" is cyanide, which forms CN- ions; this is what inhibits the respiratory enzyme.

It is conceivable that, because it is an acid, it could erode the teeth and bone away (acid erosion of teeth is permanent, at least). For this to happen, you would need an acid of a very low pH, and in sufficient quantities that it can react with enough teeth.

Now for some wild assumptions and quick calculations:
The fatal dose of cyanide, according to Health Canada, is about 1.52mg/kg bw. So for the sake of argument, we will say that he took as close to the fatal dose as possible without it being fatal. helpfully informs us that Javier Bardem, the actor playing Silva, weighs 84 kg. Therefore in order to be just non-lethal, the pill would have to contain 127.68mg of cyanide ions. The Mr of CN is 26, so the lethal amount of HCN is 0.004910769231 moles.
The pill was stored in his 2nd molar, which we will model as a 9mm*9mm*7mm cuboid (assuming it is on the upper jaw); therefore its volume is 0.000567dm^3. The pill would have had to have taken up much of this space in order to be easily accessible, so we can say that the pill has the same dimensions as the molar. Therefore the concentration of HCN (which used to be known as prussic acid, on an unrelated note), is 8.660968661moldm^-3.
Hydrogen cyanide's pKa is 9.2. Therefore its acid dissociation constant is 10^(-9.2). This is [H+][CN-]/[HCN]. Given that the concentrations of H+ ions and CN- ions are the same (because they dissociate in a 1:1 ratio), and given the concentration of HCN, it is possible to work out the concentration of H+ ions:
[H+][CN-]/[HCN] = 10^(-9.2)
[H+] = [CN-], therefore ([H+]^2)/[HCN] = 10^(-9.2)
[HCN] = 8.660968661, therefore [H+]^2 = 8.660968661*10^(-9.2)
Therefore [H+] = sqrt(8.660968661*10^(-9.2))
[H+] = 7.392362131*10^(-5)

Therefore pH (= -log[H+]) = 4.131216766
= 4.13 to 2 decimal places

Wikipedia says that there is a paper saying that solutions with pH<5.0-5.7 cause dental erosion. Therefore, Silva's pill may well have damaged his teeth. However, it seems unlikely that it could have destroyed so much of his jaw and face: the pH of wine, for instance, is around 3-4. So the acidic effect of the cyanide pill would actually be less than if you just squirted the inside of your mouth with some sauvignon blanc.

Pathology project news again

The medlink team have got back in touch; the paper I wrote last year is going to be published in their collection! Woooooooo!
...Not quite a peer-reviewed journal, but I'll take what I can get.

Saturday, 8 September 2012

Prayer as an element of medicine

         James records in his gospel that “the prayer of faith shall save the sick” 1, and according to the U.S. Centre for disease control and prevention, 45% of adults use prayer for personal health reasons in the modern age.2 Unfortunately, it is very difficult to measure the power of prayer as a part of the treatment of someone, for quite a number of reasons: firstly, because some religious groups claim that praying as part of a scientific study is artificial, so the prayers will not be answered. There are also various confounding variables, such as ability to pray (according to some, prayer is a skill to be learned )3 and fervour of prayer (this may affect the effectiveness of prayer)4. Another reason that it is difficult to study is that it receives very little funding; according to the Washington Post, “about $5 million is spent worldwide on such research”5. Critics of scientific study of prayer argue that part of the point of prayer is that it is not always answered, and that god is not a mechanism that responds in a way that is predictable, or even measurable, by humans. For these reasons, and because in such a religiously charged subject, some studies are bound to be biased, research into prayer is still very much being refined, and there are conflicting results at the moment.
There have been three main types of prayer studied scientifically to gauge their efficacy. The most obvious one is second person prayer, which is performed by someone who knows the person they are praying about. Second person prayers directly ask a higher power for the person to be helped, as do third person prayers, which are performed by a stranger. First person prayer not only includes the petition to god but also can include self-meditation beforehand, and is a separate type of prayer.

Sunday, 26 August 2012

Fat acceptance

On the subject of ethics, here's an interesting topic. There is a movement, now largely online, to end discrimination and prejudice against fat people, and whose proponents say that you can be healthy regardless of how big your waist is. According to the group, the health issues associated with obesity are exaggerated because of society's bias against fat people.

Gillon's 4 principles of medical ethics

Doctors are often asked to make decisions which have no immediately obvious "right" or "wrong" outcome. Of course, as a doctor, you sign up to do this, and you won't always need help; occasionally though, there are situations that really give one pause for thought, and when a systematic approach is necessary to ensure you have covered all bases.

The most common of these approaches (to my knowledge) is Gillon's 4 principles. The way to use this framework is to work through all of the effects of a decision relating to 4 given principles, and use that as a basis to decide what is the best thing to do. The areas to consider are: beneficence (what good can come of it), non maleficence (what harm could be avoided), autonomy (does it give everyone a choice), and justice (does it do good for the greater community). If it is impossible to decide having done this because all sides of the argument seem to be equal, then more weight is given to autonomy, because there is truly no moral difference between deciding one thing or another, so taking choice away would make any decision unnecessarily immoral.