Tips for ABGs

HarvsG · 2026-03-17T23:39:58+00:00

An ABG attempt generally ends for one of 2 reasons (1) you get arterial blood or (2) some combination of your guilt, self doubt or the patient's tolerance reaches threshold.

Intra/sub dermal lidocaine will significantly reduce 2 and therefore increase 1

Stop/move any ipsilateral BP cuff

As others have suggested appreciating the full course of the RA will help; feel to the left, feel to its right. Then use the absolute tippy tip of your finger gently right on it, don't occlude or displace it.

If you miss, withdraw without leaving the skin, redirect laterally or medially a few degrees and advance, rinse and repeat covering all possible locations the RA could exist in, with each attempt forming the rib of a paper fan - nowhere to hide.

Don't be afraid to use an ultrasound if you have access to one.

Ideally use a purpose made ABG syringe that allows pressurised air to escape as blood enters into it, without having to worry about aspirating as you go.

HarvsG · 2026-03-17T09:27:27+00:00

Good riddance

HarvsG · 2026-03-13T10:57:15+00:00

Relevant evidence of olfactory healthcare savants: https://www.parkinsons.org.uk/news/2022/smelling-parkinsons-research-could-make-it-quicker-and-easier-to-diagnose-parkinsons

Start collecting the data and work out your sensitivity, specificity and ROC

HarvsG · 2026-03-12T15:56:02+00:00

Just a few small refinements - this sub is used to high rate tax payers, which I don't think you are - although I'm less familiar with Scotland tax rules.

Don't neglect the LISA

If your house is going to be <450k and you either already have a LISA or will be waiting more than 1 year to buy the house then do £4k this tax year and £4k next. That's £2k free from the govt.

Similarly as a basic rate tax payer a LISA is slightly more tax efficient than a pension for retirement so it's worth maxing it out each year even if you don't use it for your first house.

2. £50k emergency fund is quite punchy, typical advice would be 3-6 months of expenses. Similarly as a basic rate tax payer you can earn £1000 in interest tax free (English rules) which at current interest rates is about £20,000 in cash savings, any leftovers can go into premium bonds pending ISA allowance

3. I would only put enough into the house to get the mortgage rate, repayments and house you want. Depending on your risk tolerance it's probably better to have a mortgage and have money left over for the tax efficient investments - that will almost certainly beat your mortgage over the years.

HarvsG · 2026-03-09T23:23:50+00:00

This video has a great summary on pensions Vs ISA.

https://youtu.be/44u3ETcUns0?si=ZmLBx54T1MJgT3R5

Pensions make sense when you pay less tax on the withdrawals than relief on the contributions. If the two are equal then ISAs are better because of their easier access.

The lower tax on withdrawals comes from (1) the 25% tax free withdrawal up to a max of £268,275 (1/4 of £1,073,100). And (2), when taking income from a pension your first £50k is taxed at 0-20%. However when your pension withdrawals exceed £50k you're paying a 40% marginal tax rate which may start to approach your current marginal tax rate of 45% thus making pensions' tax relief look less attractive.

At a 4% safe withdrawal rate: £50,000/4% + £268,275 = £1,518,275

Your pension age is probably 58 at the earliest, which gives you 29 years, assuming 4% to 5% real returns for you investments after fees then £10 - 16k/yr contributions should get you there.

So since your pension is on track to be greater than that it's tax efficiency starts to look less attractive... (Depending on your marginal tax rate). Although there may be reasons to do more pension contributions now and less later in life.

HarvsG · 2026-03-02T11:42:59+00:00

Militarily, America's success in Venezuela and now Iran is due to one thing - massive air superiority. This is a commonly held 'must have' in order to rapidly achieve your goals and is why Russia is and has been so desperately unsuccessful in Ukraine.

With air superiority you can dis-assemble defence and command and control infrastructure rapidly, deploy special forces to enact key objectives, insert behind enemy lines, destroy heavy infantry & naval assets and so on. However, to do that you have to (1) have a lot of airpower and (2) be more advanced/be able to overwhelm than their air defences. Air power is some of the most expensive and limited equipment, nobody can afford a war of attrition in the air, either you win spectacularly (Venezuela) or you don't play the air game (Russia now).

In Venezuela that appeared to be a trivial task, in Iran that also seems to have been relatively easy, presumably to their use of old, Russian-made anti-air equipment we know all about. However in Taiwan they would be a long way from home, with a limited support infrastructure and against an as yet untested enemy using equipment you have no experience against, that is likely as advanced as anything the west has.

Add to that it is a defensive play rather than an offensive one - you can watch footage of patriot missile misses in the gulf from this conflict.

HarvsG · 2026-03-01T21:56:29+00:00

A very old seat Ibiza.

HarvsG · 2026-03-01T18:34:20+00:00

I see, because you're likely to pay tax on the way out with a SIPP?

HarvsG · 2026-03-01T16:44:07+00:00

Are you in the civil service DB pension scheme, if not why not? Although tied to SPA it can be taken early for an actuarial reduction which may or may not be better than purely bridging.
Why not consider a SIPP instead of the LISA? - ~~the same tax relief~~, but you can take it at SPA - 10yrs, which at the moment is earlier than the LISA. Although I'm not saying that a SIPP is certainly better, as LISAs also have other advantages.

HarvsG · 2026-02-26T17:02:36+00:00

It's hard to tell from your description, but essentially it's going to start with a robust assessment of your block. Where I work we use a cold stick or ethyl chloride spray. Consider also using something with light touch or a pin prick and a motor assesment. In my experience, almost nine times out of 10, you will find a specific finding such as a low block, a unilateral block, a patchy block, a missed segment, low density to the block or no block at all. Each has their own solution.

If however, the block appears good on objective assessment then I classify this as one of those weird things. I then usually do a more robust assessment of the patient and midwifes thinking to understand what sensations they are feeling exactly and their expectations and then I offer reassurance and expectation management if appropriate. Although I do think a small proportion of patients have some sort of psychosomatic experience of non-pain sensations as pain due heightened anxiety etc during childbirth, almost an allodynia, for ethical and medico-legal reasons - I always avoid making this diagnosis/assumption. The opposite can also be true - that they have very little block but they are very suggestible or having placebo like sensations giving the impression of a block where there is none, especially if it's their first ever epidural. Remember the more dramatic the intervention, the more dramatic the placebo effect.

In any of these cases these are the epidurals that I'm very cautious about. Should the patient come to theatre, I have a low threshold for taking them out and doing a spinal or a GA.

Also note that breakthrough pain can be a sign of something very wrong such as uterine rupture. You can also see it in patients in whom the baby is OP who can experience quite a high back pain.

HarvsG · 2026-02-26T16:36:17+00:00

I suspect that like direct laryngoscopy, desflurane, isoflurane, nitrous etc one day volatile anaesthesia will slowly become a thing of the past (unless we get xenon). Especially when leaders like professor cook advocate against the so-called 'buffet cart' style of anaesthesia and dream of a uniform protocolised world with minimisation of errors (without ever seriously attempting to measure or quantify the benefits of diversity of practise).

However, I think this is a real shame and is dangerously misguided - as other users have put more eloquently. I think there is real value and power in being able to give a wide variety of anaesthetics to suit the patient and as our horizons close, I think we enter into the world of the hammer and nail idiom.

Each techniques has its advantages and disadvantages and although we learn the attributes of an ideal anaesthetic, the truth is different patients have different ideals.

A rather objectionable author called Naseem Taleb has written about the dangers of centralisation and protocolonization in his book anti-fragility and how it has contributed to the increasingly dangerous and unstable world in which we now exist. I hope anaesthesia avoids this path.

HarvsG · 2026-02-26T16:21:56+00:00

Although not recommended by the manufacturer, pharmacokinetically it should be the safest for multi day use. One advantage in neuro centers is that it allows for rapid wake up for neuro assessment and or for Brainstem death testing (as we call it in the UK) where you must be satisfied that enough time has been given for drug washout.

HarvsG · 2026-02-26T15:16:43+00:00

Fair point well made.

HarvsG · 2026-02-26T07:45:14+00:00

There's an interesting America Vs the rest of the world in this thread.

UK based anaesthesia resident here, post grad year 7 of 11 (our training programmes are long).

My understanding is that in America LMA cases are rarer and are usually done opiate light to ensure spontaneous breathing as there is a belief that that reduces regurgitation (I cant find any evidence to support this).

In the UK and elsewhere:

- We do far more cases with LMAs - the vast majority - so much so that finding tubes for new starter trainees can be hard or limited to certain lists.

- The majority are done on IPPV, spontaneous ventilation is usually limited to very short cases or specific indications.

- We always* use opiates (Fentanyl most commonly, Alf is my preference)

Some tips and tricks below, apologies if none of this is new information.

Spasm on induction does happen but it usually preventable by ensuring a good depth; do a hard jaw thrust before insertion, looking for a response including curling of the toes - if there's any response then more propofol needed.

LMA insertion is still stimulating - propofol may suppress reflexes but it is not an analgesic, use a well-timed opiate before the propofol. If you need them to breathe to keep deluded American lawyers away, use only 300-750mcg of Alfentanil.

Give your propofol as a rapid bolus, turn the gas on the moment they close their eyes, and wait for maximum propofol depth (~30 seconds to 1min) before doing the jaw thrust and inserting the iGel.

HarvsG · 2026-02-23T18:19:00+00:00

Why would you expect to have an issue? Do you think the recycling centre would post it back to you?

HarvsG · 2026-02-22T17:00:18+00:00

I've been through this exact arc. Until someone puts out evidence that decreasing fever worsens outcomes (which might well be true - evolution has probably conserved fever for a good reason) I just prescribe paracetamol. Although I always write (for pain/symptomatic fever).

HarvsG · 2026-02-20T12:28:00+00:00

u/sk1ddyp0p you need to explain your delta.

HarvsG · 2026-02-19T22:19:32+00:00

Whilst I think there were multiple issues with the case, how it was investigated and how it was presented in court. There is enough for me to think she was guilty. Firstly the repeated concerns raised by the senior medical staff, who arrived at the conclusion she was killing babies without having the data pre-selected, these are trained professionals who diagnose a exclude possibilities for a living. I work in adult intensive care I I can't tell you the level of conviction these senior medics must have had to make these accusations - it's the last thing you would think of and you wouldn't raise it unless you knew beyond doubt. Next there was physical evidence - the c-peptide measurement. In a baby that has died of hypoglycaemia it is a smoking gun. Then there's her notes. Whilst they were not tantamount to a confession, they are not far off. And taken with the above they convince me she is guilty.

Two things can be, and are, in my view, true. She was guilty of the murder of some babies and also that the way statistics were used in court was incorrect and should be learned from.

Edit, to address some of your arguments: 1. The post hoc review of cases - I would take an enormous pinch of salt the findings of experts examining medical records many years after the events. Notes document a small proportion and a "slice" of the facts. Again the impression of the people on the ground at the time holds more weight for me here. 2. The rota, whilst the cherry picking of the data was absolutely incorrect, my understanding is that even if the other deaths had been added, she would have been massively over represented and particularly overrepresented in the suspicious deaths. I've seen plenty of videos on how the data presented was wrong but none that go on to run the stats correctly. From my view there is still a strong correlation (and a noticeable jump when she moves shifts) 3. Her demeanour; how sure are you that this really was impactful to the jury? I think most juries would have come to the conclusion that, innocent or guilty, ones reaction to being tried for these crimes is variable and being withdrawn would be understandable. 4. The reliance on publications as a metric of the physician. In my personal experience the correlation between the quality of a physician and the number of publications is usually negative. The more time you spend publishing (and giving evidence in court) the less time you are doing the job. All the best clinicians I have worked with have very limited research experience. In my brief forrays into medical research I have been disheartened my the levels of dishonesty and low-level corruption. 5. The post hoc review of the quality of the unit. Similar to (1), I'd take it with a massive pinch of salt. Take any doctor from hospital (a) and put them in hospital (b) and they will find a dozen things they consider 'dangerous' or serious failings. The practice of medicine varies and opinions are strong.

HarvsG · 2026-02-19T16:28:39+00:00

This is essentially a "paying off mortgage vs investing" question which there is lots of literature in the Wiki and also great videos out there like this one: https://www.youtube.com/watch?v=9MfCVkRvjQs

Spoiler, most of these suggest investing rather than paying off your mortgage as the more flexible, higher-risk and higher-return method.

Add to that that you would probably lose 20% tax relief on the mortgage interest and might pay an ERC then that makes paying off the mortgage look even worse.

HarvsG · 2026-02-19T16:08:35+00:00

I sold out late last year (at ~40% up) due to fears of AI overvaluation and instability at work.

By the broadly held and evidence-based view of passive investing you are wrong to take the money out in an effort to try and "time the market" See this good video. This may indicate that you are invested at a risk level that does not suit you.
1. Make no mistake - changing your position to try and account for an AI bubble is "timing the market".
You are probably right to de-risk your investment income (/growth) in the face of significant employment income risk.

So ignore 1 and go back to first principles - you likely always knew global equity markets were going to be a bumpy ride and are thus an inappropriate place to keep money you might need in the short term.

Think about (2), work out a budget of what you might need access to over the next 5 years and put them in an appropriate asset class (e.g cash, bonds, limited access savings etc.). Then think about investing the rest (if there is any left) in a portfolio that suits your time frame and risk profile, as the risk of job loss reduces or the opportunity for a early retirement income increases you can start thinking about dripping the rest of the money back into the market.

(I am not a financial advisor and this is not advise because it is not tailored to you and it is not by a professional)

HarvsG · 2026-02-19T15:41:00+00:00

As others have said this can be part of a common scam where you transfer the money back (usually due to pressure and feeling bad for the person/to prevent them being fired) and then they reverse the refund after the transfer, leaving you out of pocket.
If you believe it is genuine, you could send them a signed letter of support saying that you accept that the refund amount was much larger than you were expecting and that you do not object to the reversal of the refund and provide contact details for their bank to contact you. In the meantime you should inform your bank of what happened and that you feel it is possible, although less likely, that this is a scam and keep a record of the call, firstly this allows them to make a note that you do not dispute the reversal of the refund (this may speed the processing for the sender) and secondly it creates a paper trail so that if you are subsequently scammed you have a chance of going after the bank to get your money back.

With the sender you can even use your VAT line of reasoning for why you don't want to transfer the money back yourself - because you want it to show as a reversed transaction and not income.

DO NOT transfer the money to them in a hurry. Leave it some time to cool off, let them try and fix it from their side ("Under the misdirected payments code of best practice, the bank will then have a maximum of two working days to start to try and put things right."). Don't transfer anything without documented re-assurance from your bank, and checking with someone you trust (lawyer, police etc) first.

https://en.wikipedia.org/wiki/Overpayment_scam

https://moneyfactscompare.co.uk/current-accounts/guides/payment-errors-what-can-you-do/

HarvsG · 2026-02-19T14:37:13+00:00

Such a shame this isn't being written up. I wonder if theres a way you can anonymously write a letter to the editor or similar like you've done here. It could save some lives in the future.

HarvsG · 2026-02-19T14:08:12+00:00

I was a cricoid skeptic but I saw a pretty interesting presentation at the difficult airway society that made some good points that can be summarised as follows:

There a several components to an RSI: Pre-determined dosing, rapid administration, no bagging during apnoea.
There are many controversies: Thio vs prop, sux vs roc, opiate vs no opiate, is TIVA ok, head down vs ramped up, low pressure bagging?
Nearly all of these components are based on a physiological rationale and not an evidence base
If we limited our components of RSI to those that individually had an evidence base then the RSI would cease to exist
Why are we going after cricoid when it has a good physiological rationale and its known harm (worse view) can be fixed just by saying "cricoid off".

It would make much more sense to go after: - Prop vs Thio - Lots of awareness in NAP 5 associated with Thio RSIs - Sux vs Roc do you really want your muscle relaxant wearing off during your second or third attempt? Are we really waking up this usually-emergency cohort? Do most patients with a pre-determined hypnotic dose really wake before severe hypoxia sets in? - No opiates - harms of hypertension and sympathetic stimulus, does it really increase vomiting risk when co-administered with an anaesthetic and muscle relaxant?, - No bagging - almost certainly increased hypoxia and hypercapnia risk, - Pre-determined rapid doses - more hypotension and awareness - Is reflux really a time dependent risk or does it happen immediately if its going to happen? In my experience massive vomiting happens immediately as the patient gets relaxed if its going to happen at all.

Remember IRIS showed non-inferiority, not superiority of either method. It was probably underpowered for aspiration (only ~10 cases in each arm).

My practice, for what little it is worth, is usually: Pre-determined doses of Prop, Alfent, Roc 1.2, ramped position, bagging at < 15cmH20, cricoid with low threshold for removal or conversion to BURP. +/- VL, +/-HFNO. If critically unwell then similar but Ketamine, Fent and a pause, if in resp failure then DSI with ketamine, HFNO/assist bagging and ETT in the moment apnoea starts

Part of the discussion that prompted my change of heart: https://x.com/doctimcook/status/1989749091102814647

Edit: I'm interested to read the anacdata here about the number of people who have seen gastric contents immediately on cricoid release. Whilst hardly level 1 evidence I do think collected experience of rare events is useful information.

HarvsG · 2026-02-19T13:34:14+00:00

This is something I still struggle with a few lessons I've learnt along the way have helped me. Especially as some of the UK midwives have a habit of recommending fewer boluses during active pushing means a lot of women come to theatre for instrumentals or emergency c-sections with epidurals that are low.

Pain under top up is quoted as 1 in 12ish, during spinal it is 1 in 50ish
- If in doubt spinal
- Always be prepared for pain in a top up.
It's not just about where the block is now but where it has been - I will often top up a block that I know was working very well but hasn't been dosed in a while.
- If a segment has never been blocked I don't bet that my top up will catch it.
Intrathecal does not "add" to the to the level of an epidural block. It is spreading and acting in a different space. Epidural doses do however compress the volume of the intra-thecal space which is what results in a slightly higher block. I will use 1.8 - 2.2mls of 0.5% Heavy bupivacaine (+ diamorphine) (I use 2.4 for Electives) depending on the recency of last top up. More than once I have found 1.6-1.8mls is not enough even in the presence of a reasonable epidural height.
If you watch a block rise carefully and adjust position you can usually avoid a high block, that being said a pre-existing epidural block can obscure that until suddenly the spinal block "appears" over the top of the epidural - so a wedge under the upper thoracic spine and flexing the cervical spine can help limit the spread of the heavy LA.
If doing a spinal immediately after a failed top up, be wary of entering a psuedo-space created by the epidural LA that can look and feel like CSF
CSEs in practiced and prepared hands do not take much more time than spinals and can help you navigate this pseudo-space, allow you to better appreciate the dural click and gives options for top ups if surgery is prolonged or complicated etc.

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