December 5, 2017 by Casey Carr
By: Casey Carr
The routine use of sodium bicarbonate during cardiac arrest and respiratory acidemia has been increasingly controversial. During the 1960’s, with the advent of CPR, multiple animal and in vitro studies noted that acidosis was frequently encountered in prolonged periods of cardiac arrest, and that myocardium was less sensitive to catecholamine stimulation during acidosis. Increasing evidence began to accumulate that sodium bicarbonate may not be beneficial however, and may in fact be harmful.
Perfusion failure that arises during cardiac arrest leads to tissue hypoxia, cellular anaerobic metabolism, depletion of ATP, and accumulation of hydrogen ions. At the tissue level lactate is produced, which combines with hydrogen ions to form lactic acid. Without adequate circulation, the cellular buffering mechanisms are quickly overwhelmed, leading to irreversible cell damage. When bicarbonate is administered, buffering of hydrogen ions occur, leading to increased carbon dioxide and water – with adequate circulation and ventilation, the excess carbon dioxide would than be cleared by alveolar diffusion. However, in the absence of adequate ventilation and perfusion, additional bicarbonate may accumulate as carbon dioxide, further worsening tissue acidosis, hemodynamics, and myocardial contractility.
The current AHA guideline does not recommend routine administration of sodium bicarbonate in cardiac arrest (Class 3, LOE B)
A meta analysis in 1998 (Levy, M) concluded that no human study has demonstrated any beneficial impact on survival, and several human studies demonstrated deleterious effects on physiologic end points – animal studies however were mixed in their findings. However, in a 2005 randomized control trial (Vukmir, et al), found that empiric sodium bicarbonate improved survival in patients specifically with prolonged cardiac arrest (>15 minutes). In 2016, there was a retrospective cohort study (Kim, et al), who showed a benefit in survival in severely acidotic patients (cohorts were matched based on serum bicarbonate level) and prolonged cardiac arrest.
The Bottom Line
Current guidelines recommend against the routine use of bicarbonate in cardiac arrest, without clear non-cardiogenic cause (hyperkalemia, TCA overdose). The evidence is sparse and mixed. Sodium bicarbonate may be harmful, and if there is a survival benefit, it would be found in patients with prolonged cardiac arrest or severe acidosis.
- Weng YM, Wu SH, Li WC, Kuo CW, Chen SY, Chen JC. The effects of sodium bicarbonate during prolonged cardiopulmonary resuscitation. The American journal of emergency medicine. 2013; 31(3):562-5.
Vukmir RB, Katz L, . Sodium bicarbonate improves outcome in prolonged prehospital cardiac arrest. The American journal of emergency medicine. 2006; 24(2):156-61.
- Levy MM. An evidence-based evaluation of the use of sodium bicarbonate during cardiopulmonary resuscitation. Critical care clinics. 1998; 14(3):457-83.
- Kim J, Kim K, Park J. Sodium bicarbonate administration during ongoing resuscitation is associated with increased return of spontaneous circulation. The American journal of emergency medicine. 2016; 34(2):225-9
- Velissaris D, Karamouzos V, Pierrakos C, Koniari I, Apostolopoulou C, Karanikolas M. Use of Sodium Bicarbonate in Cardiac Arrest: Current Guidelines and Literature Review. Journal of clinical medicine research. 2016; 8(4):277-83.