Dalteparin

Last night’s blog got me thinking about some of the over-and-above things we do to our patients during their time in hospital.

Dalteparin, is, I wonder an example of this.

For those of you unfamiliar with this drug – it is a relatively new class of anticoagulant which can be used to reduce the risk of and treat thromboses – that is, blood clots.

The drug is usually administered once a day, in most hospitals, in the evening. The effects last 24 hours and the idea is that by injecting a small amount of this drug under the skin, our patients will be less at risk of developing deep venous thromboses (DVTs) and their close relatives, pulmonary emboli (PEs) – the latter of which can be fatal.

When I left medical school this wasn’t standard practice, indeed this class of drug, called fractionated low-molecular weight heparin (or, LMWH) was not widely available, the drug we used, un-fractionated heparin needed to be administered intravenously with frequent monitoring of blood levels (LMWH doesn’t need blood monitoring – one shot and you are good until the next day)

With the increase in the availability of LMWH, we saw a gradual increase in use, first to treat patients suspected of DVT or PE, then used prophylactically to reduce the risk.

Back in the late 90’s when I was working in Sheffield and this medicine was still new, we didn’t know as much about its potency, consequently we used it perhaps, with inadequate caution, at much higher doses than we would use today, with the outcome that some patients died from overdoses (we now know, and it is standard practice to adjust the dose for kidney function and patient weight).

Fast forward to today and the drug is much safer than before; I can’t recall a single case where a patient has come to significant harm, and with this rise in drug safety, the swingometer has shifted to us providing this drug to virtually everyone admitted to hospital – at least if they are over 65, or, ‘unwell’.

The thinking goes that acute illness – pneumonia, sepsis, renal failure, and so on, all cause the release of chemicals into the bloodstream which alongside inactivity and often, dehydration, increase the risk of DVTs and consequently PEs.

Most hospitals have guidance to help risk-stratify, so that only those perceived to be at high risk receive the drug; after all, we don’t want to treat people who have little or no increased risk of developing a clot.

And, here is the rub.

Because the administration of the drug is relatively straightforward and, because the consequences of DVT and PE so significant (I have witnessed people unexpectedly dying of PEs), we tend to err on the side of caution and give the drug to people who are at a relatively low risk.

The consequence of this is that we are likely injecting patients, nightly, with a medicine they don’t require and which is unlikely to bring them any benefit.

You might consider this a small price to pay for the potentially large numbers of lives saved through the prevention of PEs, yet, over the past 20 years, the incidence of PEs has remained static.

venous thromboembolism.png

Heit, John A. “Epidemiology of venous thromboembolism.” Nature Reviews Cardiology 12.8 (2015): 464-474.

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Arshad, Nadia, et al. “Time trends in incidence rates of venous thromboembolism in a large cohort recruited from the general population.” European Journal of Epidemiology 32.4 (2017): 299-305.

We are  spending significant amounts of money, causing nurses additional work and subjecting patients to painful treatment that doesn’t necessarily save lives (Dalteparin only reduces the risk of DVT or PE, you can still develop one of these, even with treatment).

Is it time to re-think? To reconsider who should receive these injections (I have never had Dalteparin and I am assured it isn’t that painful, but it is an injection after all).

Rethinking would likely result in a rise in the variability of patients receiving the drug – in complex systems such as hospitals, if you blanket treat or screen everyone, there is less chance of missing-out someone because of unusual circumstances.

I haven’t been sued yet by a patient or relative for not prescribing Dalteparin (I tend to be super-aware of this), although conceivably, I could be challenged with assault for providing unnecessary treatment.

Essentially, I don’t know the answer.

Most of my patients receive a nightly injection, and, I am unlikely to change practice. The question perhaps is the application of the Golden Rule – if I were that patient, would I want a jag (jab if you are English)?

If I advise the staff to stop checking blood pressure and heart-rate, should I advise to stop administering Dalteparin?

Not only have I never received this drug, I have never administered it either, so I am not talking from a fully informed position. Perhaps I should hang-around the ward after dark and have a go, or better still, ask my patients what they think, although, as you can imagine, it is difficult to convey the sentiment of this blog at a patient’s bedside.

Let me know what you think.

Rod

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