Clinical Case 077: Fluid balancing act
This is a tough one – a clinical scenario that is unfortunately a bit too common in my part of the world. I want to know how you would go about balancing the fluids in this case, what will you use to measure the adequacy of the resuscitation / fluid administration. It is a tight rope with not much safety net! Here we go:
The Back story
Mr Beans – 60 yo. man with end-stage renal disease, he has been on HD for 3 years in a small country town satellite dialysis unit. He has the usual comorbidities: uncontrolled type 2 DM, bad peripheral neuropathy, hypertension, has had 2 separate angioplasties for coronary stenoses now > 10 years ago (no recent angina), obesity – BMI 37 with marked central adiposity, probable sleep apnoea on history – not diagnosed yet! He is on all the usual renal failure meds and calcium-control agents and beta-blocked, on aspirin but not clopidogrel.
His last admission was for APO following a week of missed dialysis which got better with BiPAP and some dialysis.
Has had multiple AV fistual formations and failures, central venous stenosis requiring a surgical bypass – so not really able to do central access about the neck! Difficult periphreal venous access.
The recent history:
Mr Beans was going well until he trod on something a week or two ago (no shoes ever worn). He developed a soft tissue infection on the sole of his right foot which was drained in ED and placed on oral ABs. The swabs came back with: MRSA, mixed coliforms and some anaerobic bacterium. He then went bush for a week for some family business, missed 2 doses of dialysis (usually 3 times a week). He returned for dialysis and got started on the machine when he spiked a fever – he had a nasty looking swollen right foot with superficial blistering and a nasty odour. The team pressed on with dialysis and decided to give him a dose of vancomycin at the end of the session. Two hours later he was becoming hypotensive. He was removed from the machine and sent over to ED.
The problem now:
Mr Beans clearly has a large purulent collection with subcut. emphysema over the whole dorsum of his foot. There is a small draining wound on the sole of the foot. His Obs: Temp = 38.2 pulse = 75 in SR, BP – 110/70, RR 20/min, he is 3 kg over his preferred ideal body weight. He lookes flushed and feels warm all over
A VBG is surprisingly normal aside from a lactate of 3.9 mmol/l. His K+ is 4.8
Of course we do an USS of the foot – which shows a lot of artefact from the soft tissue gas. On some views we can see deep fluid collections extending down between the metatarsals. It stinks, not a nice fruity Staph smell – but something else!
The way forward:
The surgeon is keen to get Mr Beans to the OR for debridement / amputation tonight. This sounds like a good idea until you realise that you are the Anaesthetic guy on call! You have just heavily sedated a Psych patient and a 27-weeker has rocked in with contractions – it is not going to be a fun night!
Questions that need answers:
(1) How are you going to assess Mr Bean’s current fluid status or need for fluid resuscitation?
(2) How are you going to decide when enough fluid is enough / or when to give some vasopressors?
(3) What are your initial / preferred plans for anaesthesia. Looking at the spine there is a large fat pad, no palpable spinous processes below the chest.
(4) Antibiotic preferences for this scenario with ESRF? Has been on vancomycin for 2 doses now, was on oral Augementin (in theory; last week)
Do you have any pearls to share on this case? Hit me on the comments, email or twitter
Some thoughts (in reverse order):
This man has polymicrobial diabetic foot infection with MRSA. Standard treatment for diabetic foot infection would be timentin or piptaz; both of these A) have quite a large sodium load B) don’t cover MRSA. I think it would be fair to call it synergistic gangrene at this point (based on the USS description) and go for meropenem +- lincomycin. I don’t know what variety of MRSA this is, and you don’t mention this man’s ethnic background, but among the Indigenous population the NORSA rate is >50% (of all SA), I’ve heard (I’m not a microbiologist). The linco will help treat the majority of NORSA.
So in summary, I would use meropenem, clindamycin and vancomycin in this man as triple therapy.
3. I have no experience in anaesthesia – but would this be suitable for ultrasound guided combined femoral-sciatic block? (I once plated an ankle with that sort of block – worked well, but not having tourniquet was not fun).
If his peripheral neuropathy is really bad, perhaps it doesn’t need that much anaesthetic after all. How extensive is the synergistic gangrene? Lisfranc was famous for being able to perform his eponymous amputation with great alacrity.
2/1: I would try to use an ultrasound endpoint: either leg-raise fluid responsiveness, IVC collapse, or the appearance of pulmonary oedema.