Monday, 12 November 2007

Life-long learning #2

After the shenanigans of the weekend, it was back to work as normal today. This morning, I was giving an anaesthetic under the supervision of one of the consultants. I had just given my patient the injection that sends him off to sleep and was using the bag and mask to breathe for him.

One of the side-effects of the anaesthetic our patients is that they can rapidly drop the patient’s blood pressure. (For the medics among you, they cause a decrease in myocardial contractility whilst simultaneously causing profound vasodilation). This means that we always check the blood pressure and make sure it is stable before we allow the surgeons to start operating.

I press the button to start the blood pressure check, but the screen just reads:

Error: Cuff Leak.

The blood pressure cuff isn’t working and our ODP goes off to get a new one. The consultant turns to me and says, “What are you going to do now?” Referring to the fact that the machine was unable to ascertain if the patient’s blood pressure had fallen to dabgerously low levels.

“I’ll feel his pulse,” I say
“Which one?”
“The carotid” I feel the man’s carotid pulse. “He’s got one.”
“And this tells you the blood pressure is at least how much?”
“I don’t really know the exact figures”
“60 systolic. What are you going to do next?”
“Feel his radial pulse.”
“Good. Does he have one?”
“Yes, but it’s not very strong”
“If he’s got a radial, how high do you think his blood pressure is?
“Yes, that’s right. You said it’s not very strong, so this man’s blood pressure will be just over 80 systolic.”

Our ODP has now returned with a new blood pressure cuff and we get a reading from the machine:

Blood pressure: 84/51

I was super-impressed.
You learn something new every day.

- Michael.


Anonymous said...

Good theory, but discredited! Radial disappears before femoral before carotid as BP drops, but exact limits vary from patient to patient. I think your consultant was lucky this time.

There was a paper about this about four years ago that showed the exact numbers were pretty variable. Still, impressive when it works.


The Junior Doctor said...

Anon - fair enough, but I suppose the point the consultant was making is that to trust your clinical skills. They will guide you through when technology fails.

Anonymous said...

Fair play - and that one's certainly a good point to learn.

kingmagic said...

In these days of technological wizardry and monitoring it is possible to rely too much on machines.

In the Ambulance Service we are taught to read the patient as well as the machine.

Examples: Blood Glucometer reading saying 8.0 when patient is sweating+++ confused++ with history of diabetes and recent exertion with missed meals. I gave Glucagon and patient recovered within 10 mins although subsequent bm at A/E said 4.

BP readings in their boots incompatible with consciousness. I always take a manual reading with my steth if the automatic bp is playing up.

ECG displaying NSR whilst patient showing all S&S of MI. 12 leads have made it easier but still difficult to see posterior MI,s.

My wife complains that I twitch and shake a lot in bed after a shift at work...could the basis for some research somewhere.