At the end of each scene, you’ll get a chance to test your knowledge; Are their comments true or false?
Last time, we met Clara Clearvessel and learnt some of her beliefs. This time we hear from David.
Scene 2 – the blood letting lab
David Clotterfield hadn’t been to the lab for his INR test for a while. Since his wife’s death, he was finding it hard to adjust; she’d always been the one to remind him of appointments.
Now this rather anxious young girl wanted to get in for her test ahead of him.
“Go ahead” he said, “Doesn’t bother me. I sometimes wonder why I come for tests anyway. I always take 3 mg of warfarin a day, even though they keep telling me to increase it.”
The girl looked shocked, “You shouldn’t do that! Aren’t you worried you’ll have another clot?”
He tried to reassure her. “I’ve never even had a clot. They just put me on warfarin because of my irregular heartbeat. I’ve got to stay on warfarin for life so I think it’s best to get used to the same dose everyday.”
She looked even more anxious now, “Well, maybe it’s because I’ve had two clots in my lungs, but I like to have lots of tests and get my warfarin dose changed if my INR drops below 2 or above 3.”
David tried again, “My GP never seems too bothered if my INR is a bit low. I think it’s probably better to run low so I’m not at risk of bleeding.”
As the phlebotomist called “Clara Clearvessel” and the girl went into the bloodletting room, David briefly thought that she was just like his pharmacist son who fussed far too much and was always going on about how now mum was gone, his dad should take more interest in his own health and managing his warfarin.
Like Clara, you may be shocked at David’s attitude, but I have certainly met a few patients like him. We’re not going to examine his insistence on staying on a constant dose of warfarin, but two of his other statements
What do you think of David Clotterfield’s statements? True or false?
David Clotterfield has atrial fibrillation and treatment for this should be continued indefinitely to prevent blood clots and reduce the risk of a stroke. Anticoagulation is necessary even if the irregular heart beat only occurs intermittently. Anticoagulants would only be stopped if the atrial fibrillation is cured with a treatment such as catheter ablation, however even after this procedure many patients still need to remain on warfarin and can only stop if they have a low risk of stroke.
If you answered true, you’re in good company, for this is the mistake many doctors make when they dose patients. When INR Online pharmacy testing first started, we found that pharmacists kept the INR in the therapeutic range for longer than doctors who erred on keeping it too low. After the pharmacists had been managing warfarin for a while, they too erred on the too low side. I suspect this tendency to keep the INR low occurs because doctors and pharmacists are worried about bleeding, but keeping the INR too low is potentially dangerous. If you take warfarin for atrial fibrillation, your doctor is probably trying to keep the INR results between 2.0 and 3.0. Studies have shown that the risk of a stroke goes up quickly if the INR falls below 2.0 but the risk of bleeding does not really increase until the INR is above 4.0. Therefore keeping the INR slightly above the treatment range is safe but letting it fall too low is dangerous.