When I first moved to Hong Kong, I kept making eye contact with passengers instead of drivers when crossing the road on foot.
In New Zealand (my first experience driving on the left), I turned on my wipers (on a sunny day) the first couple of times entering a roundabout (the turn signal is on the other side of the steering wheel). Also, I couldn't resist the urge to glance over my left shoulder for oncoming traffic in my blind spot when making left-hand turns, despite the fact that traffic approaching me from there would need to be driving the wrong way down the road.
Thank goodness that the manual shift pattern and pedal layouts are kept the same between left-hand and right-hand drive models. Driving in South Africa could have been a disaster had the shift pattern been reversed.
Really though, just use _your_ left and right as most people do, because as has been mentioned, the standard is for doctors to refer to and visualise left and right from the patients perspective - so every time you do something different they have to transform, translate or clarify which increases chance of mistakes.
That's before even getting into the assumption of face to face orientation over a phone... is that in virtual terms, or in terms of absolute orientation, I hope they took into consideration the curvature of the Earth.