Medevac!

 The ever fertile mind of Ian Robinson this week brought us 'Medevac!' - a game simulating the process flow for casualty triage, evacuation and treatment in a near future conflict. Fundamentally it is a flow chart with casualties moving through various stages of the treatment pipeline, and it is mainly intended to highlight the decision making at each stage and potential bottlenecks.

The game is being developed in conjunction with the Royal Army Medical Corps, but the overall framework is flexible enough to cope with other armed forces ways of doing things. This sort of stuff is very familiar from my time spent doing process analysis, modelling and optimisation in the latter days of my IT career.

Here is our "battlefield" , casualties will appear each turn (15 minutes) based on OR casualty rates for brigade level engagements at various combat intensities. We can evacuate up to ten casualties per turn to the Unit Aid Post, which is next in line.

There is a possibility of 'friction' however, which prevents us moving anyone - air/artillery strikes, drone attacks or whatever, which are a real problem for casevac in Ukraine. At the moment it is 'all quiet' so nothing is happening.

Ooer, suddenly we are into low intensity combat and five casualties rock up. These are classified in standard British Army usage into triage levels T1, T2,T3,T4, with 1 being the most urgent. T4 are dead or mortally wounded. Each casualty has some personal info, rank, arm of service etc, wound location and estimated surgery time. In this bunch we've got one T2, three T3s and a T4. Two of the casualties are 'red' (enemy) who have very Russian looking names. There is also a civilian in there with a rather Estonian looking name.

There isn't any friction so we can evacuate all of these back to the aid post.

The intensity of combat ramps up to high, and we are suddenly getting ten or more casualties a turn, and coupled with occasional interdiction, we can't evacuate everyone, so choices have to be made, which is the whole point of the game. We started out with a very Iraq/Afghanistan approach of evacuating the most critical casualties, but in an ultra modern high intensity conflict, that may not be the best approach...

After a few turns of fighting, the Unit Aid Post (UAP) was brimming with casualties, some of whom started to die on us. Obviously we needed to get them out of there and back to the field hospital, and to do that we needed transport, for which we had one Chinook and three Landrover ambulances.

So, who gets a ride in the ambulance? The main problem is limited transport capacity, again based on Iraq/Afghan practice, the more serious casualties take up more room - British Chinooks were actually fitted out with a mobile operating theatre. So eg our ambulance can take 1 x T1, 2 x T2 or 4 x T3 or combinations thereof.

We loaded this one up with a T2 and 2 x T3, including both our Russians and stuck some more serous casualties on the Chinook. We probably made some bad loading decisions with the first wave of casualties as at that point we didn't have that many to handle.

And here is the problem with ambulances - the little white boxes on the left are the areas they need to travel through, so at best they take three turns to get to the field hospital, although in this case this one is interdicted, so delayed a turn. While they are being transported, the casualties may degrade in condition, so there is a fairly good chance T1s and maybe T2s will die on the ambulance ride.

The main problem though, is we just don't have enough transport to deal with the volume of casualties coming in. The ambulances at best take six turns to do the round trip, while the Chinook takes two, the UAP is soon piled with casualties.

Things are a bit calmer at the field hospital. The first casualties have arrived (2 x T1 and 1 x T3) via Chinook and spend a turn being prepped for surgery. Once they are in the hospital, they stop degrading significantly in game time, so at least they won't get any worse. When they arrive they take a turn to prep, but again, we weren't exactly overwhelmed with business at first. 

There are four surgical teams, and each casualty goes into surgery with a minimum number of turns required to deal with them plus a randomised surgery completion time once the minimum is complete. In our enthusiasm we had failed to notice that one of the T1s needed 12 (!) turns of surgery minimum, complete on a 5+ - so that was one surgical team out of action for 15 turns straight away. Many of the T3s were 2 turns, complete on a 3+.

So once the floods of casualties started to pile up at the hospital, we tended to prioritise the least critical just to get them sorted and out of the way with one 'lane' reserved for T1s. Once out of surgery they went into the recovery wards, three wards of eight beds each. Our recoverees were a mixture of armed forces, civilians, prisoners and men and women, so we also had to decide how to partition up the allocation of wards and beds, bearing in mind the need to guard the prisoners.

I won't do a blow by blow account, suffice to say, all the major sections (UAP, ambulances, surgery) were utterly overwhelmed by the volume of casualties - 120 in the course of the game covering around five hours. As a result we had to seriously think about prioritisation at each step and ended up selecting a good number of T3s, many of whom were NCOs and ended up packing the ambulances with them. The T2s generally got to ride the chopper and the poor old T1s got left in the UAP.

Longer term, we considered changing the way the ambulances and choppers worked, and just packing the casualties in without special treatment for the T1s and T2s in the transport itself - so essentially a reversion to WW2 practice and also the practice adopted by NHS Ambulance services after a brief experiment with paramedic roadside treatment which actually reduced overall survival rates from RTAs.

That of course was the main point of the game - to identify potential bottlenecks and discuss both how you would prioritise treatment and longer term, how you might change the way the process worked, allocation of resources to the various stages etc. In that it succeeded admirably, so a very interesting and informative game. Lets just hope we don't get into a serious shooting war soon. 

Some of the lessons from Ukraine in a world of intense and indiscriminate missile and drone warfare is that casevac can take days, helicopter and softskin evacuation is virtually impossible anywhere near the front line (Bradleys are being used as frontline ambulances) and that hospitals can only be in place for around 48 hours before they get stonked, so they have to move repeatedly. Dear me. Can I get back to pushing toy soldiers around please?