Clinical Case 120: Vomiting VBG
Gday – I am off on leave this month – so here is a quick case from the files.
It’s an unusual VBG. I will tell you a few features on the history and you need to work out the diagnosis and tell me how you are going to manage this!
The patient is a 25 year old chap who presents with 2 main symptoms: intractable vomiting and the near obsessive need to shower – long hot showers. He has presented today because the ondansetron wafers that his GP prescribed have not been helping with the vomiting and his hot-water system is not able to keep up his need for hot showers!
He certainly looks dry and miserable. His palms and soles are macerated from all the hot water. He gets an IV sited and a quick blood gas is drawn….
So here are the questions:
(1) What is the diagnosis?
(2) Which meds will you try to truncate the vomiting?
(3) What fluid will you choose to correct his metabolic derangement ??
The hot showers are a dead giveaway for cannabinoid hyperemesis.
I know that hypochloraemic alkalosis is the classic use of saline, but I’d be tempted to use Hartmann’s anyhow, on the basis that you don’t want to bring up the Na too quickly.
Great case Casey!
1. Cannabinoid hyperemesis from chronic THC. Gas shows a metabolic alkalosis which fits the clinical history, with a very deranged metabolic profile. There is no respiratory compensation, but this patient could be hyperventilating for other reasons.
2. I think I’d prefer to get on top of the potassium first, but in the interim IV ondansetron and metoclopramide is probably a good place to start, followed by droperidol as a second line.
3. 100ml NaCl with 10mmol KCl, probably run at 200ml/hr via CVC. Also needs cardiac monitoring and hourly gases for the first few hours until the numbers improve.
^As an aside, what are thoughts on having to use a CVC for KCl at this rate? If I place one good cannula in the ACF and another in the GSV and run 10mmol of KCl an hour at both sites, what is the difference between this and a CVC?