Thank you so much for your prayers!
Last night was eventful, with lots of blood draws, x-ray, CT scan, but today has been fairly low key.
They are keeping Josiah another night for monitoring, but overall, they feel he is looking good.
The doctors think he got really dehydrated, so they have lowered the speed of his LVAD a bit, as well as one of his medications.
They don’t see any issues around his driveline, which is great news. But they are growing cultures just to verify there isn’t any infection.
Unless something crazy happens in the next day, he should be able to go home on Friday. However, anyone who has spent any length of time at a hospital knows that you should always hold loosely to any predictions of when you will be going home. 
Prayers up for Josiah that the Doctors have wisdom and insight, and peace for Josiah, Kim and Eric and the whole family.