Calcium and Sodium Bicarbonate Efficacy in Out of Hospital Cardiac Arrest

So not to harp on this too much, but also at the behest of our EMS colleagues, I wanted to share a brief lit review on the efficacy of out of hospital cardiac arrest (OHCA) use, or lack thereof, of sodium bicarbonate (SB) and calcium use. This post is *different* than the prior ones as it focuses on out of hospital care! There is a TLDR at the bottom if you're a "I'm happy for you, or sorry that happened" kind of reader. 

Calcium:

Calcium plays an important role in cardiac muscle contraction and is generally acknowledged for its inotropic and vasopressor effects. These effects could be beneficial in the setting of cardiac arrest. Two small, randomized trials from 1985, including a total of 163 patients, found that administration of calcium did not result in a significant increase in return of spontaneous circulation for patients with out-of-hospital cardiac arrest and asystole or pulseless electrical activity. However, both trials had point estimates that favored calcium. Since then there have been no randomized clinical trials assessing the effect of administration of calcium during cardiac arrest. 

A randomized control in Denmark was done in 2020-2021 by Vallentine et al. (citation is at bottom of this post), which asked is calcium administration in OHCA improved ROSC compared to saline. Known as the Calcium for Out-of-Hospital Cardiac Arrest, or COCA Trial, patients were randomized to receiving calcium or saline after their first dose of epi. Primary outcomes were sustained ROSC for 20 minutes, and secondary outcomes were survival to 30 days and survival with favorable neurological outcome at 30 days. 

This study found no significant difference between groups to get sustained ROSC. There was also no difference in survival or neurological outcomes at 30 days. Multiple follow up studies (also cited in the bottom of this post) were performed and found no improved outcomes at a year, and potential worse outcomes in the calcium group, suggesting harm. 

Sodium Bicarbonate:

Sodium bicarbonate (SB) administration has been considered an important part of treatment for severe metabolic acidosis in cardiac arrest. Administration of SB seems a reasonable intervention to counteract the severe metabolic acidosis caused by hypoxia, poor perfusion and increased lactate production in cardiac arrest, in an attempt to mitigate the adverse effects of acidosis. Correction of metabolic acidosis with SB was recommended by early advanced cardiac life support (ACLS) guidelines published in 1976 and SB was the medication most frequently used during cardiac arrest until the mid-1980s. Data published in the 1970s raised concerns that SB administration during cardiac arrest can worsen the outcome after cardiac arrest and emphasized the adverse effects of bicarbonates, including increased osmolality.

ACLS guidelines this past decade have made SB a class III drug in OHCA (not recommended). However it is a class IIB (mild recommendation to give) for TCA overdose, hyperkalemia. A lit review by Velissaris et al. (again linked in the bottom of this post) summarized recent literature on the use of SB, which essentially can be summed up as, SB increases intracellular acidosis, reduces cardiac output, shifts oxygen dissociation curve to the left, hypernatremia, and hyperosmolarity. The bicarb also breaks down into CO2 and worsens tissue acidosis. 

Another study, this by Kawano et al. examined the use of SB in OHCA, and found that its administration could worsen long term neuro outcomes. This was an observational study that included over 13,000 patients, and examined sustained ROSC, survival to 30 days, and favorable neurological outcomes at 30 days. SB groups had worse survival rates and worse neurological outcomes than the non-SB groups. Odds ratio for survival in SB group was 0.64, 95% CI 0.45-0.91, and the OR for favorable neuro outcome was 0.59, 95% CI 0.39-0.88. Obviously this is not a randomized control, but it does paint a poor picture of the use of this medication. 

TLDR: Sodium bicarb and calcium have a litany of evidence showing they do not provide any benefit in OHCA, and there is increasing evidence that they may actually cause harm to give. 

One final additional statistically tidbit I found fascinating while looking into these studies (which has less to do with SB and CC). A randomized control study on epi use in OHCA was performed in the UK by Perkins et al. This cited a number of other articles (all of which are cited below) to compare the number needed to treat for various interventions in ACLS. I wanted to present those here and let folks reflect on them.

NNT for epi in OHCA is 112

NNT for CPR by a bystander in OHCA is 15

NNT for early defibrillation in a shockable rhythm in OHCA is 5.

So second TLDR is early compressions and early application of pads during arrests are often the most life saving interventions we have! Happy reading and happy Tuesday!

Vallentin MF, Granfeldt A, Meilandt C, et al. Effect of Intravenous or Intraosseous Calcium vs Saline on Return of Spontaneous Circulation in Adults With Out-of-Hospital Cardiac Arrest: A Randomized Clinical Trial. JAMA. 2021;326(22):2268–2276. doi:10.1001/jama.2021.20929

Vallentin MF, Granfeldt A, Meilandt C, Povlsen AL, Sindberg B, Holmberg MJ, Iversen BN, Mærkedahl R, Mortensen LR, Nyboe R, Vandborg MP, Tarpgaard M, Runge C, Christiansen CF, Dissing TH, Terkelsen CJ, Christensen S, Kirkegaard H, Andersen LW. Effect of calcium vs. placebo on long-term outcomes in patients with out-of-hospital cardiac arrest. Resuscitation. 2022 Oct;179:21-24. doi: 10.1016/j.resuscitation.2022.07.034. Epub 2022 Jul 30. PMID: 35917866.

Vallentin MF, Povlsen AL, Granfeldt A, Terkelsen CJ, Andersen LW. Effect of calcium in patients with pulseless electrical activity and electrocardiographic characteristics potentially associated with hyperkalemia and ischemia-sub-study of the Calcium for Out-of-hospital Cardiac Arrest (COCA) trial. Resuscitation. 2022 Dec;181:150-157. doi: 10.1016/j.resuscitation.2022.11.006. Epub 2022 Nov 18. PMID: 36403820.

Velissaris D, Karamouzos V, Pierrakos C, Koniari I, Apostolopoulou C, Karanikolas M. Use of Sodium Bicarbonate in Cardiac Arrest: Current Guidelines and Literature Review. J Clin Med Res. 2016 Apr;8(4):277-83. doi: 10.14740/jocmr2456w. Epub 2016 Feb 27. PMID: 26985247; PMCID: PMC4780490.

Kawano T, Grunau B, Scheuermeyer FX, Gibo K, Dick W, Fordyce CB, Dorian P, Stenstrom R, Straight R, Christenson J. Prehospital sodium bicarbonate use could worsen long term survival with favorable neurological recovery among patients with out-of-hospital cardiac arrest. Resuscitation. 2017 Oct;119:63-69. doi: 10.1016/j.resuscitation.2017.08.008. Epub 2017 Aug 10. PMID: 28802878.

Perkins GD, Ji C, Deakin CD, Quinn T, Nolan JP, Scomparin C, Regan S, Long J, Slowther A, Pocock H, Black JJM, Moore F, Fothergill RT, Rees N, O'Shea L, Docherty M, Gunson I, Han K, Charlton K, Finn J, Petrou S, Stallard N, Gates S, Lall R; PARAMEDIC2 Collaborators. A Randomized Trial of Epinephrine in Out-of-Hospital Cardiac Arrest. N Engl J Med. 2018 Aug 23;379(8):711-721. doi: 10.1056/NEJMoa1806842. Epub 2018 Jul 18. PMID: 30021076.

Berdowski J, Beekhuis F, Zwinderman AH, Tijssen JG, Koster RW. Importance of the first link: description and recognition of an out-of-hospital cardiac arrest in an emergency call. Circulation 2009;119:2096-2102.
Hasselqvist-Ax I, Riva G, Herlitz J, et al. Early cardiopulmonary resuscitation in out-of-hospital cardiac arrest. N Engl J Med 2015;372:2307-2315.

Kitamura T, Kiyohara K, Sakai T, et al. Public-access defibrillation and out-of-hospital cardiac arrest in Japan. N Engl J Med 2016;375:1649-1659.

EMS Protocol of the Week - Seizures

For this EMS protocol review, I wanted to focus on prehospital seizure treatment. Both the adult and pediatric algorithms are the same and utilize the same medications and weight based dosing. Paramedics are authorized to utilize 3 different benzodiazepines to treat active seizures:

Midazolam (Versed) 0.2mg/kg IV/IN/IM. If effect is not achieved, may be repeated after 5 minutes. Max single dose is 5mg and max cumulative dose is 10mg.

Lorazepam (Ativan) 0.1mg/kg IV/IN/IM. If effect is not achieved, may be repeated after 5 minutes. Max single dose is 2mg and max cumulative dose is 4mg.

Diazepam (Valium) 0.2mg/kg IV, infused over 1 minute. If effect is not achieved, may be repeated after 5 minutes. Max single dose is 5mg and max cumulative dose is 10mg.

The Medical Control Option for refractory seizures is to administer additional doses of any of these standing order medications. Some considerations for medication choice include availability, as Lorazepam requires refrigeration is not always carried, nor is IV Diazepam due to supply issues. Of these 3 medications, Midazolam is the fastest acting. With mounting doses of benzodiazepines, loss of spontaneous breathing should be a consideration, but typically can be outweighed by ceasing the seizure activity.

Finally, some patients with known seizure disorders, usually pediatrics, will have home prescriptions for PR diazepam, also known as Diastat. Occasionally, you will receive calls from EMS asking if they can administer this home medication. This formulation is not in the algorithm and has a much more erratic absorption than other routes of benzodiazepine administration. Because EMS is already present and has access to faster acting and more reliable medications like Midazolam, this should be administered instead.

Check out the RAMPART trial for a more in depth study on IM vs IV benzodiazepines and their efficacy!

EMS Protocol of the Week - Emergency Childbirth

Hi all, 

This week we will be focusing on Emergency Childbirth! 

The prehospital approach exists as a progression of care based on the provider’s level of training. CFRs start with ABCs and monitoring vital signs for shock. They will check for crowning and if present prepare for imminent delivery. 

This is a general outline to help providers: 

1) Apply gentle pressure against the delivering newborn’s head to prevent tearing of the perineum 

2) Gently clear the airway of secretions using a bulb syringe

3) Support the head and chest as the newborn delivers

4) Repeat suctioning as necessary prior to spontaneous or stimulated respirations

5) Gently guide the head downward until the shoulders appear. Deliver the other shoulder with gentle upward traction

6) Thoroughly but rapidly dry the newborn with a clean, dry towel 

After delivery, delay clamping of the umbilical cord for up to 1 minute after uncomplicated delivery. Wrap the newborn in a dry, warm blanket/towel. Assess the mother for postpartum hemorrhage and shock. When safe to do, place newborn on mother’s chest. 

If the on-scene team is BLS-trained, they will be able to assess and help manage breech presentations, prolapsed cord, nuchal cords, intact (not ruptured) amniotic sacs, shoulder dystocia, and multiple births. See the attached protocol for detailed recommendations for these special considerations. 

KEY POINTS: 

• Consider supine hypotension syndrome as a cause of shock 
  

• Newborns are subject to rapid heat loss and must be kept warm and dry 
  

• Miscarriage usually occurs at less than 20 weeks of gestation. Begin resuscitative efforts of the newborn if the gestational period is unknown 
  

• The turtle sign is when the newborn’s head retracts back into the vagina, and is an indication of shoulder dystocia 
  

• It is no longer suggested to perform aggressive suctioning of the newborn when meconium is present  

• Do not aggressively suction premature newborns 

More words to read at www.nycremsco.org

John Su