“A medical practitioner is negligent if he fails to use the level of skill, knowledge, and care in diagnosis and treatment that other reasonably careful medical practitioner would use in the same or similar circumstances. This level of skill, knowledge, and care is sometimes referred to as ‘the standard of care.’ You must determine the level of skill, knowledge, and care that other reasonably careful medical practitioners would use in the same or similar circumstances, based only on the testimony of the expert witnesses.”
[CACI Jury Instructions [citations omitted]]