It should also be reminded that you should follow IEC 60601-1 when considering any modifications.
Clause 8.11.3.5 - Cord Anchorage would seem to be appropriate. A p-clip may not meet the a) indent and the screw used to fix should not have any other function to meet the d) indent. If the power inlet plug is the means of disconnection then blocking this without updated instructions for use would be an issue. Interestingly as the device must be tested with the manufacturer using a different cord may be a breach of the certification!
The requirements of clause 8.11.3.6 - Cord guards must also be followed.
