Human factors

Figure 41.1

‘Swiss cheese’ model

Each of the slices of cheese represents barriers that should prevent A leading to B. However, such checks and balances can fail. This is represented by the holes in the slices. For A to lead to B, the holes of all the intervening slices need to line up. Simplistically viewed, the more checks that are put in place, the less likely an error is to occur. However, increasing complexity can be counterproductive, as humans will avoid or modify multiple steps to make life easier.

Consider the following critical incident:

The wrong dose of a drug has been administered to a patient by a clinician. Why?

We know that the clinician should have checked the details of the prescription and the calculations and ensured that this all matched up with the formulation and strength of the medications they administered. People do not usually deliberately give the wrong dose and therefore it is not unreasonable to conclude that the clinician thought they had checked and matched everything as described.

So why did the error occur?

Further investigation revealed that the two drugs had been replaced in one another’s normal positions in the ward trolley. The packaging of the two drugs was very similar (Figure 41.2).

Figure 41.2

Similar package designs of two medications

The clinician picked the medication from its usual place, thought the packaging was familiar and therefore did not actively check the name and concentration of the drug. Habit can blind us to what we are doing. The problems of uniform packaging have been recognised and highlighted through a national adverse incident reporting system and recommendations made that packages for different strength medications should now look completely different. This change in practice is an example of how human factors theory is used to reduce the risk of error.

In the working environment, we may be present at the right time to observe the breaching of a barrier that would normally prevent errors occurring. It is critical that we are vigilant for these breaches and draw the attention of our colleagues to them in order to prevent the completion of an error chain. Events or conditions that are suspected of representing potential breaches in barriers preventing harm are referred to as red flags. The more red flags that arise, the greater the risk of an adverse incident occurring and therefore the greater the need to alert those involved to stop and review the situation.


Problems with communication underpin a significant proportion of critical events.

When the speaker and listener do not share the same language, the obvious solution is to use an interpreter. However there are limitations to discussions carried out through a third party. What about the matters that arise if one of the parties is communicating using their second language? Even when all parties are utilising their native tongue, nonverbal signals carry as much, if not more, information and meaning, than the words themselves. Nonverbal communication, outside the actual words we use, has been shown to contribute up to 93% of what we understand.2 Barbour’s study identified that 38% of communication relates to how words are said (volume, pitch, rhythm, etc.) and 55% body language (facial expressons, posture, etc.). When those trying to communicate come from different cultural backgrounds, both verbal and nonverbal elements can be completely misinterpreted by both parties.

Studies have shown that we understand around 61% of verbal and >50% of written communication, the remainder being miscommunicated, misinterpreted or simply misunderstood. It is not hard to see why in a busy clinical environment, when multiple tasks are being undertaken, and contact is frequently electronic or telephonic rather than face to face, miscommunication occurs so frequently. The process of communication can be described as three separate phases:

1 The Sender – This is the process within which the originator articulates their message in their mind, in what they perceive to be a meaningful and contextual manner.

2 The Channel – This is the medium of communication chosen: verbal, nonverbal or written.

3 The Receiver – This is the process within which the intended recipient makes sense of the information. This is easily distorted by the use of euphemisms or localised terminology.

The resulting outcome in a noisy highly pressured clinical arena is unsurprisingly one of poor information exchange. A technique to improve communication is the feedback loop. This is a process by which the receiver repeats the message back to the sender to acknowledge receipt and confirm that it has been correctly deciphered. It is quick and simple to use, easy to teach and has been shown to produce immediate benefits in busy clinical areas where requests and instructions are being passed on at breakneck speed.

To aid with communication when handing over care from one team/person to another, the SBAR tool is recommended (Box 41.1).

Box 41.1

S – Situation: a concise statement of the problem

B – Background: pertinent information related to the situation

A – Assessment: analysis and considerations of options – what you found/think

R – Recommendation: action requested/recommended – what you want to do

This formalises and structures the information transfer helping avoid assumptions of knowledge and highlighting the plan for ongoing care (recommendation). In summary, the discussion above only begins to touch on the complexity of human communication. Beyond this there are many layers of subtlety in our interactions. To try and mitigate the risk of miscommunication, it is vital that both talkers and listeners actively engage in the process.

Body language and hierarchy

All individuals should always be aware of their nonverbal signals. Messages that say ‘I’m bored’, ‘I’m tired’ or ‘I don’t value you’ can inhibit another person from passing on a vital piece of information. The presence of a steep hierarchy can be particularly dangerous as it promotes an attitude of indifference to the input of those further down the pyramid. A culture where junior staff do not feel empowered to speak directly to senior staff, or senior staff are dismissive about concerns raised by junior staff, is inherently unsafe. If the clinical assistant walks into theatre and sees an expanding pool of blood under the operating table, they should feel able to voice their concerns. Whether or not it proves to be clinically important, their input should be positively acknowledged, as next time they might be the first to identify a critical concern.

Speaking up

A useful communication tool, utilised by the airline industry, is shown in Box 41.2.3

Box 41.2

Stage Level of concern
P – Probe I think you need to know what is happening
A – Alert I think something bad might happen
C – Challenge I know something bad will happen
E – Emergency I will not let it happen

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Mar 11, 2017 | Posted by in OBSTETRICS | Comments Off on Human factors
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