Page 42 - Safety Risk Management for Medical Devices
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Understanding Risk 21
Table 17.3 in Section 17.2. With the 5-value Harm severity model, an enhancement
to Figure E.1 of the Standard [3,7] can be made (see Fig. 4.2).
Note that P 1 has dimension, but P 2 is dimensionless. Therefore, Risk, which is
P 1 3 P 2 , has the same dimensions as P 1 .
Some P 1 examples:
• Probability of exposure of the patient to a damaged cannula is 1 in 1000
uses.
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• Probability of a patient not receiving pacing from their pacemaker is ,10
per patient-year.
Examples of P 2 :
• Probability of death from intracranial hemorrhage is 2.5%.
• Probability of permanent or life-threatening injury from electrocution is 4%.
