Can any medics here tell me how the list is prioritised?
a few thoughts that may help explain how it works...
the reason for getting everyone in early rather than at staggered times is that it usually allows for more surgery to get done. If the anaesthetists and surgeons do a round at the start of the session we can just crack through the list without stopping then (and because we're all suckers we usually turn up earlier than the shift starts to make sure we have enough time to do that). If we have to down tools between every patient because they've been given staggered start times then that interrupts the list and doesn't allow time for sorting out any surprise problems that become obvious and less work gets done and waiting lists go up. We know it's really dull for patients to be waiting (and even worse if it is a bad day and someone gets postponed), but until there's enormous redundancy in the systems we have that's really what we're stuck with.
there are loads of different factors that affect how lists are ordered and different things can have different priorities apparently similar lists on different days.
Often it'll be done in order of clinical urgency - cancer surgery for example will often go before non-cancer surgery... but that's not helpful when the whole list is cancer.
More complex patients will often go nearer the top of a list because a) starting a complex case when you're fatigued isn't ideal and b) it gives longer to recovery/declare any problems later on the in the day. Again, not that helpful if the entire list is complex patients (as is increasingly the case).
Procedures that require other specialties (eg. xray) may go later on if their start times don't line up with the theatre start times or if there are multiple theatres using xray in the same session. Or if another surgical team is needed then often they'll try and plan things so that both teams are able to get max work done without sitting around and twiddling thumbs...that might mean that patient is earlier/later in the list.
If it's a mixed list of kids and adults, often it'll be the kids going first. Where there's multiple children then often it'll go in age order.
Patients who've been postponed before will often be put at the top of the list to stop it happening again (there are financial penalties for postponing surgery if it doesn't get done within a pretty short timeframe).
Patients with infection will usually go last on the list because the cleaning process takes longer so having that dead time when the theatre wouldn't usually be active is better.
the exact list order is often not confirmed until the team-brief at the start of the session because it's really not that uncommon for things to need to be re-jigged - patients condition might have changed so different kit or operation is needed/ someone's not followed their pre-op instructions so things have to be done differently/ unexpected problems come up with kit...particularly if that's loan kit/ someone's called in sick so the list order changes to try and allow time to sort an back-up plan out/ the rep the surgeons needed is stuck in traffic/ someone else in a disastrous way has turned up and cannot wait for the emergency theatre or needs a specific person's skill set/ the lights or ventilation have stopped working so the estates department need to come to fix things, etc.
If it looks like things are going Pete Tong there is usually quite a bit going on the background trying to work out if there's capacity to slot things into different lists (for example if a list has had a cancellation could there be scope to get a quick extra done from a different list...not always possible but often worth a try).
I hate going through those long anxious hours without drinking
that should be less common these days - 'sips til send' is the more common rule now and allows sips of water until someone is sent for to go into theatre. There are times where it's not appropriate so don't assume it's always the case, but it's fine to ask about it if they don't bring it up automatically.