BGOTW #29

1. Ensure rapid IV access has been obtained. If a peripheral IV catheter cannot be quickly placed, consider an IO catheter. Don’t forget that the jugular vein is a nice big vein that is easy to access.
2. Give 10cc/kg of an isotonic crystalloid solution over 5-10 minutes. Be certain to specify the timeframe. Setting the IV pump to 999 delivers 16mL per minute – too fast for this 3kg cat. Either calculate the correct rate, or do it a different way! I would draw up 30cc of fluid in a 30 or 60cc syringe (label the syringe) and use that to deliver the bolus by hand, or by syringe pump IF the tech can have the pump running within 1 minute – don’t let the equipment delay administration in this case.
   1. I would avoid normal saline because the high chloride content will worsen acidosis. Plasmalyte A, Normosol R, and Lactated Ringer’s solutions are better choices if they are available. If Normal saline is all you have, then that’s what you will use.
3. Dextrose: it seems like everyone has their own formula for dextrose administration. I don’t like to make people do math during a resuscitation, so I keep it simple and do it the same way every time: draw up 1cc/kg of stock 50% dextrose solution, dilute it with an equal volume of sterile water or saline diluent (whatever your hospital uses), and give over about 1-2 minutes IV. This cat weighs 2.9kg so we will round to 3kg to make things easy. So I would draw up 3cc of stock 50% dextrose, dilute with 3cc of saline, label the syringe, and give IV over 1-2 minutes.
4. Calcium: you can use either calcium gluconate or calcium chloride. I prefer calcium gluconate because I am usually working with peripheral IV catheters, and if it is extravasated calcium gluconate is less likely to cause tissue to slough compared to calcium chloride. Small animal formulation calcium gluconate is 10% and large animal formulation is 23% – be sure to know what you have.
   1. Again there are various formulas for how to do this, and again I like to keep it simple. I start with 100mg/kg IV over about 10 minutes while monitoring the heart rate. 100mg/kg is 1cc/kg of 10%, or roughly 0.5cc/kg of 23% (this gets you 115mg/kg instead of 100mg/kg but is close enough, in my opinion, for the first dose during a resuscitation – you will have to make your own decision about this conversion difference, and if you are worried about that difference). Since I have small animal preparation calcium gluconate in my kit, I would draw up 1cc/kg (3cc for this cat), and dilute with 2 (two) parts diluent – so about 6cc of saline for a total of 9cc total volume. Label the syringe. Give 1cc per minute while monitoring the heart rate (ECG, pulse oximeter if it is matching well, or by palpation and auscultation if finding working monitors is going to delay things). Slow down administration rate if the heart rate drops persistently by more than about 15-20bpm from baseline (in the clinic I would give the technician a specific number – for this cat who started with a HR of 100 I would say slow down if HR <90, stop administration and tell me if the HR drops below 80bpm, resume when HR improves to >90bpm).

Reassess your patient after these interventions – you might have made enough improvement to intubate, or you might find you no longer need to intubate – that’s what happened with this cat.

Cat 2 is a little more challenging. He might be hypovolemic based on the history and exam – it’s a difficult to tell from the information we have available to us. With his impressively high creatinine, kidney injury/failure of some flavor is clearly a problem.  Based on the limited history we have uncontrolled hyperthyroidism or other chronic kidney disease that has decompensated are my primary concern. The cause of his deterioration and what his baseline function are will help us to determine what his prognosis might be. Urinary obstruction, either urethral or bilateral ureteral, are definitely concerns, but the list of differentials includes a bunch of other stuff like progression of chronic disease with acute insult, pyelonephritis, other septic process, etc. His bladder is reported to be small and easily expressible so urethral obstruction is not currently a part of the problem for him. Urinalysis results would be useful.

BUT – don’t get too caught up in the exact cause yet. This cat is very unstable and needs meaningful interventions right now to buy us time to figure out all those other things. While I am aware of his heart murmur, and I don’t know if he is currently able to make urine, he is not showing signs of volume overload right now – and actually acts like he may be hypovolemic. I am very comfortable starting IV fluids with a 10cc/kg bolus over 10 minutes. I would do this the same way as for cat #1 above.

This cat also has an impressively low ionized calcium. Supplementing is going to be a bit controversial, but in the end you will probably need to give him a little bit of calcium to optimize his hemodynamics. The controversy over giving him calcium is: he has a phosphorus of 46mg/dL (something you can probably guess was going to be present based on his initial labs, and information that came on the complete chemistry that was run just after his blood gas), and the low calcium is a normal physiologic response to the deranged phosphorus. Giving calcium greatly increases the risk of mineralizing soft tissues. My argument however is he has to live long enough for that to become a problem, and that requires that his heart and vessels have enough calcium to contract/constrict and raise his blood pressure.

I would start with a fluid bolus in this cat, monitor the effect this has on blood pressure and the perfusion parameters, and give a small dose of calcium probably starting with half of my normal dose (discussed above for Cat #1). Quickly make some additional assessments of volume status using ultrasound and response to fluid administration, and as long as there is enough volume and calcium on board, start vasopressors early. If possible I would get an arterial line in early (if not possible keep going with what you have) for pressure monitoring.

Depending on the owner’s goals and a better understanding of this cat’s medical history (hopefully things will be clearer once the rDVM opens the following morning) dialysis might be considered – this patient might not be a good candidate if this cat has late stage kidney disease secondary to uncontrolled hyperthyroidism. But in other patients with this degree of azotemia and acidosis, who have different circumstances leading to their kidney injury, ability to medicate at home long term, etc it would be something to seriously consider.