When it's 5 am and the lab calls you the nurse with a critically low calcium level of 5.5 what should you do?
A. Stop everything you're doing and frantically page Dr Happy from a dead sleep?
B. Calmly assess the situation to avoid interrupting your work flow and Happy's beauty sleep.
If you are a nurse with excellent clinical skills, ground in science and capable of generating independent thought, your answer will always be B. Because 99.99999999999999999% of the time a critically low calcium level is not a critically low calcium level as determined by your laboratory parameters.
I've had this discussion before. Most recently with the decreased urine output quandary. I've talked about critical lab values when nurses act like robots. Many hospitals don't allow nurses the ability to use their thinking skills to not call physicians. I write at least 5 times a day do not call parameters, and yet I still get called with robotic like precision. Somewhere along the way, nursing schools have failed their students. Or perhaps the students have failed themselves.
I'm here to educate every nurse that every walked this earth on why it's not necessary to call the critically low calcium level 99.99999999999% of the time. Why? Because it isn't critical. And if it isn't critical, you don't have to waste your time and mine trying to communicate a non critical lab value. This is where a little extra nursing education would go a long way to understanding why choosing action plan B over action plan A is the right course of action.
Physiology lesson for the day: How to interpret the low calcium level.
About 99% of a body's calcium is found in bone. Of the 1% that isn't about 50% of it is free (metabolically active ionized form), and 40% is bound to albumin. When a lab reports a calcium level, they are reporting a lab who's value is determined by the album level in the patient's body. If the patient's albumin level is low, the reported calcium level will be low as well. This is what prevents a low calcium level from being a critically low calcium level. If an effort is made by a nurse to correct the low calcium level for the patient's albumin level action plan B will be implemented 99.9999999999% of the time.
This corrected calcium formula is very simple. For every one gram below four a patient's albumin level is reported, you must increase the reported low calcium level by 0.8. So if the lab calls you with a low calcium level of 5.5 and the patient's albumin level two days ago was 1.0, you must increase that 5.5 by ((4-1)*0.8) or 2.4 and you get 7.9 for the corrected calcium level. Clearly this is out of the critical range. Action plan B could saftely be initiated and the patient would survive another noncritical critical lab value.
This is called the corrected calcium level. Most of the time it may remain a low calcium level, but rarely is it a critically low calcium level. If after correcting for albumin, the calcium level remains critically low, than perhaps action plan A should be considered. But only after basic science skills have been exhausted. I found one nurse wishing to learn how to correct a low calcium level for the albumin level. This is proactive nursing.
Critically low calcium levels are rare in my hospitalist population. The differential is fairly limited for a low calcium level, and having a critically low level is a rarity. Compared with the number of work flow interrupting and beauty sleep ending pages for a critically low calcium level, the actually incidence of critically low calcium levels on my service could be counted on one hand in seven years. Hopefully this little piece of continuous medical education will help nurses divert unnecessary calls to physicians all across this country by not calling noncritical critical calcium levels, levels which require a simple understand of math and physiology to put it all together.
