T:Slim X2 – early thoughts, incl Basal IQ

After almost 5 years on the trusty Animas Vibe, I was fortunate to move to the Tandem T:Slim X2 insulin pump in April 2019. I’d been hankering after it for some time, mainly because it incorporates Dexcom CGM and is beautifully slim – designed to fit the small Levi’s waistline pocket.

My comments are those of a relatively inexperienced pump user, but these are my personal pros, cons, plus some tips to avoid pitfalls.

First the good stuff

  • No more huge lumps and bumps in pockets – and it sits far more comfortably in a bra than other chunky dinosaur pumps!
  • As with the Vibe and Dexcom G4, there’s no need to carry a receiver or phone if using Dexcom G6 with the T:Slim. My preference is to carry as little diabetes kit as possible. (NB ditching the phone will encourage less use of social media, so is welcomed by my other half!)
  • Basal IQ is AMAZING! It kicks in whenever blood glucose is dropping fast, not only when it’s nearing 4mmol, thus avoiding so many unexpected hypos. With fewer extreme lows, I’ve even regained – albeit intermittently and just now and then – some hypo awareness, which I’ve not had for decades. Control IQ (for managing highs) will hopefully arrive via an online link some time in 2020.
  • No need to wait the usual 4 years for pump updates – an outstanding 5* unique feature for me, particularly as tech developments are now arriving fast and furiously.
  • The screen is legible in sunlight – the Vibe was DREADFUL as a CGM receiver and was for me, a keen walker with poor hypo awareness, a significant safety hazard when outdoors.
  • The touch screen navigation, with speedy access to all pump functions is great. No more scrolling down several menus on the Vibe for different functions. The touch is sensitive and works really well.
  • Temp Basal rates can be set in very precise minute by minute segments starting at 15 minutes, I’m using this repeatedly to really great effect. Slight drawback: the max is 250% which is insufficient for me if I’m fighting a stubborn high.
  • Basal profiling is very comprehensive: using a copy and paste-like feature, it’s super simple to create profiles with different carb ratios etc.
  • Insulin delivery is very slow. I often found boluses hurt with the Vibe, even using short cannulae on the slow delivery option. Tslim is totally pain free.
  • I rarely use a bolus calculator, but the screen design for this feature is extremely neat and user friendly.
  • Finally, the design is elegant, even beautiful – the B&O of insulin pumps! This really matters to me, as does the great choice of pump skins available from PumpPeelz.

And the less positive stuff

  • The cartridge fill is very fiddly, you have to withdraw air bubbles from the flexible plastic ‘insulin sack’ with a syringe (part of the consumables) before injecting the insulin into the vacuum you’ve created. All a bit of a faff. I’m now totally competent, but it took a few weeks practice to feel this way. The flexible sack was apparently designed to allow a much slimmer pump profile.
  • As my insulin sensitivity is high (12-18u Total Daily Dose) the 300u cartridge and the minimum ‘fill’ is far too generous. Minimum recommended fill is 95u but if following the 3 day change, I’d have to throw away many precious insulin units if recommendations were scrupulously followed (conversations with T:slim users in the USA indicate many people use the same cartridge for 6-7 days to avoid waste!). In theory, I’ll need to order double the amount of insulin using this pump, though my needs are low, it shouldn’t cost the NHS a great deal I’m told! In practice, I do regularly move my steel set after 2-3 days and keep using the insulin up and I’ve not had any problems so far (I keep a very close eye on CGM fluctuations which might indicate lack of insulin potency).
  • Every bolus initiates a buzz and soft vibrate, followed by a second buzz on completion of delivery, meaning you can’t bolus silently if you notice BGs rising at the theatre, a concert or other very quiet environment. A bizarre feature IMHO, presumably included to reassure. I’m HUGELY embarrassed by any noise during performances and may even consider removing the pump if I’m performing myself. Unfortunately my ears are sensitive and this feature can’t be silenced, but it is pretty quiet so hopefully it’s only me that’s bothered by this!
  • For me, the pump alarms too much! I only use the vibrate alarm, but for example, it buzzes when insulin is low, when the battery needs charging, when occlusions occur – which happens frequently. I press ‘Resume Insulin’ and it’s always been fine, so not sure what that’s about….! I’m told the mechanism is just very sensitive, but it’s annoying.
  • The tubing has a ‘pig tail’ – see top photo – that can cause a lump under tight clothing if not carefully placed.

And a few tips:

  • I’d strongly advise ensuring you put T:slim back to sleep after any procedure. Being slapdash about this, I’ve had many false alerts saying an action hadn’t been completed when I’d not been aware I’d started anything. Seems very easy for buttons to get pressed when putting pump back in its hiding place!
  • When replacing the cartridge, be super careful not to mix up the newly filled with the empty one. I once put the old one back on the pump – doh…🤦‍♀️

So I’m really loving my T:slim X2 and will update when I’ve tried Basal IQ in the coming months – and Control IQ in 2020.

                                                         My fab PumpPeelz!


#TAD 2016


#TAD2016 panel facilitator Dr Peter Hindmarsh with Laura Cleverly, Joe Eldridge, Weston Nordgren, Lis Warren, Richard Lane OBE, Anne Cooper & Jamie Reed MP.  Below: Dr Partha Kar and Justin Webb 



March 2016 presentation Talking About Diabetes (#TAD2016) at Imperial College in London, organised by Dr Partha Kar, with the Radio 4 journalist, Justin Webb.  Demonstrating the Palmer Injector ‘gun’ I used for injections in the 1960s (and yes, it went deep and did hurt, but I still loved this gadget – see more below!)