At what point do you intervene (DKA with suspected metabolic acidosis)?

[medicdan]

From a recent patient, and coming off a discussion in class, and hoping to pick the brains of our experienced and wise members.

Hypothetical patient:

26 year old DKA, sugar "HI", otherwise healthy (no pulmonary disease, other PMH). Presenting with uncontrolled DKA and rapidly decreasing mental status.

VS:
RR: 26, deep
HR: 110
BP: 104/60
ETCO2: 15

ABG:
pH 6.9/ pCO2 15/ HCO3 10 (a partially compensated metabolic acidosis)

So... by my understanding, given the relative acidosis in the blood, the body is trying to correct it by increasing minute volume (rate and tidal volume), and because this has come on over time, the body has released bicarbonate, decreasing the HCO3. This increase in Ve is working, but not enough, and the pH is acidotic.

Presuming we know everything about this patient, they're breathing at 26 times a minute, and deep (10 or 12mL/kg).

At what point do we intervene with this patient's respirations? They're obviously trying to compensate with their respirations, but as mentioned, not compensating well or fast enough. It's a matter of time before they tire our and cannot maintain the Ve. Can we effectively maintain those volume and rate without a mechanical ventilator (most BVMs are max 800ccs, right)? Can we really bag that depth and rate "manually"? If we don't give enough volume or rate, we can cause arrest quickly (think of 4ml/kg*70kg ibw*12bpm= Ve of 3.3L compared to 10 ml/kg*70kg ibw*26bpm=Ve of 18.2L).

At what point of exhaustion is it prudent to use medication assisted intubation (Midazolam/Lorazapam) and pass an ET tube? For those with RSI, when do you consider it? What measures do you look for?

Again, this stems from a patient I had recently, and a discussion in class. Are there other interventions we should consider that i'm ignoring before thinking about intubation? How can we stave off this exhaustion and maintain the physiological response? What options do we have for longer transports?

 

[NYMedic828]

In my experience, DKA never presents with a rapid onset. It takes days to weeks to set in. Mental status changes occur very faintly and often go unnoticed for quite a while.

It is also not a condition that we can treat outside of a hospital. We can treat symptoms of it but we cannot treat the actual disease process. (Normally all we can treat is the dehydration)

The treatment of severe DKA is often done under close monitoring, controlled insulin administration and precise lab work that we do not have at our disposal.

As for treating breathing the same rules apply as for any other patient. If it is not adequate to sustain life, intervene. By the point of DKA the body is more acidic then kussmauls respirations can fix. Ventilate them in an adequate manor, administer fluids and transport to a capable facility.

 

[STXmedic]

Where do you work? Because I had this EXACT patient last night. Down to the age and vitals.

 

[medicdan]

I very highly doubt we had the same patient, especially given the great distance between us.
So... what did you do?

 

[usalsfyre]

The time to intervene is....when the ETCO2 starts climbing. You can not ventilate via PPV as well as the patient without causing damage.

 

[STXmedic]

I was the fire unit (non transporting). Managed to get a 500mL bag started and a dose of Zofran in (our patient hadn't reached the altered loc stage yet) before EMS got there and transported. Knowing the medics that transported, I highly doubt anything else was done. But we were also less than 5 minutes away from 6 different hospitals...

 

[Brandon O]

I have had little experience with such patients, but I am very dubious whether what you're describing is feasible -- i.e. normalizing this patient's pH solely through assisted ventilations. At best it's a temporizing measure, doesn't address the underlying derangement, and the fact that the patient is already so acidic despite Kussmaul respirations suggests that simply trying to "dial up" that parameter isn't going to get us very far.

More specifically, although you can probably squeeze a rubber bag at an almost infinite speed, actual ventilatory rate is going to be limited both by expiratory time (which you can't very well accelerate), and compliance (since the faster you try to squeeze the more likely you're going to fill the stomach). Intubation would help the latter but not the former.

I would say, assist the patient to maintain and perhaps slightly increase their current respirations, give fluid, perhaps consider bicarb, and get them to a setting that can fix the hyperglycemia.

 

[NYMedic828]

I have had little experience with such patients, but I am very dubious whether what you're describing is feasible -- i.e. normalizing this patient's pH solely through assisted ventilations. At best it's a temporizing measure, doesn't address the underlying derangement, and the fact that the patient is already so acidic despite Kussmaul respirations suggests that simply trying to "dial up" that parameter isn't going to get us very far.

More specifically, although you can probably squeeze a rubber bag at an almost infinite speed, actual ventilatory rate is going to be limited both by expiratory time (which you can't very well accelerate), and compliance (since the faster you try to squeeze the more likely you're going to fill the stomach). Intubation would help the latter but not the former.

I would say, assist the patient to maintain and perhaps slightly increase their current respirations, give fluid, perhaps consider bicarb, and get them to a setting that can fix the hyperglycemia.

I don't think NaHCO3 administration is warranted without lab values? I don't know of any doctor here that would approve a medic to administer a weight based dose of bicarb to a living patient.

 

[Brandon O]

I don't think NaHCO3 administration is warranted without lab values? I don't know of any doctor here that would approve a medic to administer a weight based dose of bicarb to a living patient.

In the scenario presented labs were available. Obviously in most prehospital settings that wouldn't be the case, unless you have one of those cool iStats. Or maybe an extended transfer, but I can't imagine a hospital shipping someone like this out (other than down the street) without stabilizing them somewhat.

 

[Handsome Robb]

I don't think NaHCO3 administration is warranted without lab values? I don't know of any doctor here that would approve a medic to administer a weight based dose of bicarb to a living patient.

For what it's worth we have bicarb on standing orders for known TCA ODs with hypotension, seizures, dysrhythmias or cardiac arrest. Different setting all together but the first three still generally are alive

I don't think bicarb in the field is going to make a huge difference for a DKA patient. Temporarily yes but is it going to matter in the long run? Probably not.

 

[MSDeltaFlt]

This is a metabolic problem, not a respiratory problem. You're not going to assist ventilations unless CO2 is high (as in respiratory failure). You will treat everything else when those readings fall in your protocols' accepted ranges to treat.

Intervention on metabolic problems takes time... as in 3 days or more, usually a week... in the ICU. Not in the back of the Sick Wagon or Boo Boo Bus.

 

[NYMedic828]

In the scenario presented labs were available. Obviously in most prehospital settings that wouldn't be the case, unless you have one of those cool iStats. Or maybe an extended transfer, but I can't imagine a hospital shipping someone like this out (other than down the street) without stabilizing them somewhat.

I meant it more as a general statement not necessarily pertaining to this case.

To my knowledge DKA is usually corrected by a slow insulin drip, electrolyte and fluid replacement and frequent monitoring (ICU) I've never had respiratory called for any DKA patient I've brought in but I have also never had one go beyond loss of consciousness. I'm sure given time without anyone tending to them or calling for help the symptoms progress substantialy.

 

[medicdan]

I meant it more as a general statement not necessarily pertaining to this case.

To my knowledge DKA is usually corrected by a slow insulin drip, electrolyte and fluid replacement and frequent monitoring (ICU) I've never had respiratory called for any DKA patient I've brought in but I have also never had one go beyond loss of consciousness. I'm sure given time without anyone tending to them or calling for help the symptoms progress substantialy.

Thanks all for your responses. I appreciate the approaches. I know this isn't a condition we can approach treating in the field, and should be corrected over a series of days, my interest is in causing as little harm as possible, and not worsening the metabolic acidosis. Is it in the patient's best interest to wait for them to tire out, then intervene with intubation and oxygenation, or be proactive and try to match their minute volume before it becomes a problem?

Thanks

 

[usalsfyre]

In a person with no other comorbidities, I've been told they can Kusmaul for a few days before its an issue...

 

[Aidey]

You will never be able to ventilate the pt at the rate and depth that they are ventilating themselves. These patients don't really fatigue the same as the severe asthma or pneumonia patient.

Edit: Damn you and your fast posting Kyle.

 

[Smash]

I'll play devil's advocate.

You have a patient with a falling conscious state and a :censored::censored::censored::censored:ty pH. Might that suggest a fair degree of fatigue? There is a limit to how long respiratory muscles can continue working at the rate at which they are in this patient. It may be longer than in other patients, but it is still finite. How long have they been cranking away before we finally see them? Along with this extremely high work-rate comes even more acidosis, which is not doing this patient any good.

Now, if conscious state is falling, one assumes that at some stage we will have an at risk airway as well as potential loss of respiratory compensation (which they are relying on to stay alive) So how far down that slope do we let this patient slide before we intervene? If we take over control of airway and ventilation we can maintain their respiratory compensation whilst also taking away a portion of the acid being produced by respiratory muscles that are slogging away. Win!

Of course intubating these patients is terrifying, as we take away the compensatory mechanism that is largely keeping them alive, so if we are not slick with getting that tube down and ventilating them, things can go very, very bad very, very quickly. Even more so if the person ventilating decides to aim for a normal EtCO2 without thinking about the metabolic acidosis they are trying to deal with in the first place. I've seen it happen and it was bad.

So do we do it in the back of the ambulance? Or wait until we get to hospital and hope for the best? I don't have an answer to that, it depends on where, when, who and how.

 

[abckidsmom]

In a person with no other comorbidities, I've been told they can Kusmaul for a few days before its an issue...

The trouble is that it's usually a few days into it before we get the call. We usually only get called for these people when they lose their mental status.

I'm with Smash, though. You can assume obvious and severe acidosis, and a blind amp of bicarb or so may be what they need to hold on to the edge of the metabolic cliff for one more hour. It's a very case-dependent, individualized decision making event though.

 

[Brandon O]

Now, if conscious state is falling, one assumes that at some stage we will have an at risk airway as well as potential loss of respiratory compensation (which they are relying on to stay alive) So how far down that slope do we let this patient slide before we intervene? If we take over control of airway and ventilation we can maintain their respiratory compensation whilst also taking away a portion of the acid being produced by respiratory muscles that are slogging away. Win!

Nah, lose. You're not going to accomplish much, and in exchange you've intubated a patient who didn't need it (need it). If the hospital isn't far, why do it? And if it is far, it's not going to be enough. How big is the margin between those categories? I would say zero in nearly every case. (If the patient is reaching respiratory failure, that's a different matter, but that's a matter of maintaining ABCs, not trying to make progress on the acidosis, which will probably have them peri-arrest anyway.)

This is like hyperventilating TBI, or Trendelenburg for shock, or similar temporizing measures. You know it doesn't do much, you know it won't last long, so if it doesn't cost much you might try it to buy a couple minutes, but if that won't be enough to matter, just pass. And if it does cost a lot (e.g. intubation), definitely pass.

 

[d_miracle36]

Just heard of a case at a local hospital in my area very similar to the one presented but this patients abg was much worse. The er doc entertained the idea of intubating the patient. The patient much like yours was compensating. He decided to not intubate as long as the respiratory compensation was adequate. Stated that the patient could compensate more efficiently than he could on a ventilator(dont know how true this is). So he treated the DKA with standard therapy and no bicarb was given. Hours later the patient showed marked improvement. I think as long as respirations are adequate I would also elect to not intubate. That and the fear of intubating a severely metabolic acidosis patient would frighten me.

 

[d_miracle36]

Here is a great podcast on intubating a severe dka patient.
http://emcrit.org/podcasts/tube-severe-acidosis/