BT_SQ 1.7 Describe microshock and macroshock and the mechanisms for preventing these, with particular reference to ensuring the compatibility of medical procedure, treatment area, and medical equipment used.
Electrical safety is a subject which many candidates seem to have trouble with.
The examiners consider it an important topic and ask it regularly.
Because of the environment you are practising in, you may underestimate the importance of electrical safety. In a hospital I worked at some time ago, there were several staff members who received electrical shocks before RCDs were introduced.
I gave a talk on the topic when I was a registrar, and dug up all sorts of reports of electrocutions. Anesthesiology 1973 Feb. 38:181-3 has an example of this kind of incident.
Rather than give True/False statements in this post, I will give a series of questions, which cover the important areas in the topic.
- Why is the domestic power supply “earthed”?
- What risks occur because of the “earthing” of the power supply?
- What is the earth wire connected to?
- If you touch a live wire, how is a circuit formed?
- What is an RCD and how does it protect against shock?
- What is the difference between an RCD and a circuit breaker?
- Why does shock from domestic power induce VF, whilst shock from a defibrillator terminates it?
The answer to the first few questions can be found in Magee & Tooley.
RCDs are explained well in Russell if you can find a copy.
The 2015 Miller Cap. 109 covers electrical safety, but I find the explanations somewhat unclear. It has a lot on isolated power supplies, and does have a diagram which you can extrapolate to answer question 4. They call RCDs Ground Fault Current Interrupters.
The previous edition of Miller has electrical safety in chapter 100. Both editions have a couple of dubious statements on earthing. More on that in a later post…