Any Benefit to Sodium Bicarbonate in DKA?

12 May
May 12, 2014

Sodium BicarbonateIn a prior post, we discussed the use of an initial insulin bolus in the management of diabetic ketoacidosis (DKA).  Today we will address another facet of DKA management, for which there is less than optimal evidence and that is: Any benefit to sodium bicarbonate in DKA?  Consensus guidelines for the management of DKA recommended administering sodium bicarbonate to DKA patients who present with an initial blood gas pH of < 7.0. That recommendation was updated and changed in 2009 to limit sodium bicarbonate use to DKA patients with blood gas pH of < 6.9.  More recently, Chua et al. published a systematic review of 44 articles discussing bicarbonate administration and Duhon et al. published the largest retrospective review of DKA patient with presenting pH of < 7.0.

What are the most recent studies evaluating: Any benefit to sodium bicarbonate in DKA?

 Chua et al (21906367)Duhon et al (23737516)
ObjectiveEfficacy and risk of bicarb administration in severe acidemia in DKADetermine whether bicarb therapy is associated with reduced time to resolution of acidemia
MethodsSystematic review of pubmed databaseRetrospective cohort of DKA pts with initial pH < 7.0 who did vs did not receive bicarb
Results44 articles included
-Heterogeneity in pH threshold, concentration, amount, & timing of bicarb administration
-Transient improvement in metabolic acidosis
-No improved glycemic control
-Associated risk of cerebral edema in pediatric pts
No study involved patients with a pH < 6.85
86 patients
-No difference found in:
1. Time to resolution of acidemia
2. Time to hospital discharge
3. Time on IV insulin
4. Potassium requirement in 1st 24 hrs
-Subgroup analysis of pH <6.9 (n=20) showed no statistical diff in time to resolution of acidemia
ConclusionEvidence does not justify the administration of bicarbonate for emergency treatment of DKABicarbonate is not associated with decrease time to resolution of acidemia or time to hospital discharge for DKA patients with initial pH < 7.0

The most interesting and revealing observation in reviewing this data is that there is significant heterogeneity when discussing bicarbonate therapy in DKA

Clinical EndpointsDosing of Bicarbonate
1. Correction of Acidemia
2. Time to Glycemic Control
3. Cardiovascular Stability
4. Resolution of Coma
-Intravenous Bolus vs Infusion
-Fixed vs Weight Based Dosing
-Threshold pH:
1. Initiate at pH < 7.0 vs 6.9
2. Treat to a pH > 7.0 vs 7.2
 

If you are going to initiate bicarbonate, what clinical endpoint are you treating to, how much bicarbonate are you going to order, how are you going to administer it, and if you are seeking resolution of academia, what is your threshold cut off for resolution? Finally, do any of these endpoints have any clinical significance in patient outcomes?  In the end no, bicarbonate administration makes numbers look transiently better, but does not change any clinically relevant outcomes based on the best evidence to date. Unfortunately, even with all of the DKA that presents to emergency departments, we do not have more robust, prospective, randomized and placebo controlled trials to help us address this clinically un-answered question that dates back to the beginnings of Emergency Medicine as a specialty, but at this time best evidence does not support the role of bicarbonate in treatment of DKA.

Take Home Points

  • Neither a recent systematic review, nor largest single retrospective cohort of severe DKA support routine use of bicarbonate therapy in DKA
  • Bicarbonate is associated with risk of cerebral edema and prolonged hospitalization in pediatric DKA

 

Other posts on…Any Benefit to Sodium Bicarbonate in DKA?:

Bibliography

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Darrel Hughes

University Health System Clinical Specialist, Emergency Medicine at University of Texas Health Science Center at San Antonio (UTHSCSA)
REBEL EM Guest Contributor and Author
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8 replies
  1. Alex K says:

    Algorithms often have <7.0 or <6.9 as a possible indication for bicarbonate therapy but what I have noticed is often absent is a trigger for respiratory rate/distress. If acidosis is causing a severe increase in respiratory demand, even at pH of 7.1, would alkaline infusion be potentially helpful? Looks like the answer is still no based on the lack of data to support a decreased time to resolution of acidemia but I wonder if any of these studies looked at intubation rates/respiratory symptoms.

    Reply
    • Salim Rezaie says:

      Hey Alex,
      Great to have you on the blog. Yes the ADA which is older guidelines does recommend bicarb at < 7.0 or <6.9, but these studies were published after the fact and best evidence IMHO. Unfortunately the studies did not evaluate intubation rate as best I can tell. Salim

      Reply
  2. Daniel says:

    Been told bicarb amp if ph was that low and about to intubate to help maintain. What would be the approach you recommend?

    Reply
    • Salim Rezaie says:

      Hello Daniel,
      Physiologically this makes sense. If you HAVE TO intubate a DKA patient then yes an amp of bicarb may help stabilize CV status. I would try my best not to intubate if at all possible, bc it is almost near impossible to keep the patient in resp alkalosis to blow off all the CO2 from their acidosis. There are no studies on this that I am aware of. Another great post that mentions use of bicarb late in DKA, and hints at your questions is here as well: http://www.pulmcrit.org/2014/05/four-dka-pearls.html

      Hope this helps.

      Salim

      Reply
  3. jim c says:

    great review…..
    never made sense to use
    unscientific view but i would still use to get a transient increase when their BP is in their boots i.e so acidic that the heart just cannot pump – again no evidence — just seems sensible

    Reply
    • Salim Rezaie says:

      Hey there Jim,
      Now we are talking…You are talking about the crashing DKA patient and basically throwing the kitchen sink at them. And I agree it is not based on evidence, but I too would consider using bicarb in the situation you are discussing. I don’t however use it in the patient who has a low pH and “holding their own.” In this case we are treating a number to make ourselves feel better, but really there is no benefit to the patient. Appreciate you reading and great point about the crashing patient

      Salim

      Reply
  4. Darrel Hughes says:

    Hi Jim,

    I think it is worth noting that neither the systemic review or the retrospective series was able to assess “BP in the boots” or “ketoacidotic coma”. The authors were unable to show benefit in the undifferentiated DKA patient with pH < 7.0. However, Viktor Rosival just published a nice review article in Journal of Diabetes and Metabolism that highlights the link between VERY low blood pH and decreasing activity of the glycolytic enzyme phosphofructokinase. He makes a strong case for correcting VERY low blood pH with an alkalizing agent for treatment of coma in DKA.

    Darrel

    Rosival et al., J Diabetes Metab 2014, 5:11

    Reply

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