Does bicarbonate level decrease in cardiogenic shock?

From the Guidelines

Yes, bicarbonate levels typically decrease in cardiogenic shock. In cardiogenic shock, there is reduced cardiac output leading to poor tissue perfusion and oxygen delivery. This results in anaerobic metabolism and lactic acid production, causing metabolic acidosis. As the body tries to compensate for this acidosis, bicarbonate is consumed as a buffer, leading to decreased bicarbonate levels in the blood, as noted in the definition of cardiogenic shock which includes signs of hypoperfusion such as metabolic acidosis 1. Clinicians should be aware that a decreasing bicarbonate level can be an indicator of worsening shock and tissue hypoperfusion. Normal bicarbonate levels are typically 22-26 mEq/L. Values below 22 mEq/L, especially when trending downward, should raise concern in a patient with suspected cardiogenic shock. Management focuses on treating the underlying cause of cardiogenic shock and supporting circulation. This may include inotropic medications, mechanical circulatory support, and addressing any reversible factors. While sodium bicarbonate administration is sometimes considered for severe acidosis, it's generally not recommended as a routine treatment for the decreased bicarbonate seen in cardiogenic shock, as it doesn't address the underlying issue of poor tissue perfusion, and recent guidelines do not support its routine use 1. Monitoring trends in bicarbonate levels, along with other markers like lactate and base excess, can help guide resuscitation efforts and assess the effectiveness of interventions in cardiogenic shock. According to the most recent guidelines, management by a multidisciplinary team experienced in shock is reasonable, and placement of a PA line may be considered to define hemodynamic subsets and appropriate management strategies 1. Some key points to consider in the management of cardiogenic shock include:

• Immediate assessment and intervention to support circulation and address reversible factors
• Use of inotropic medications and mechanical circulatory support as needed
• Monitoring of trends in bicarbonate levels, lactate, and base excess to guide resuscitation efforts
• Consideration of transfer to a tertiary care center with cardiac catheterization and dedicated ICU capabilities for patients with refractory cardiogenic shock 1.

From the Research

Bicarbonate Levels in Cardiogenic Shock

• Bicarbonate levels have been studied as a predictor of mortality in cardiogenic shock patients 2.
• Low serum bicarbonate levels at admission have been found to independently predict mortality in patients with cardiogenic shock 2.
• The relationship between bicarbonate levels and cardiogenic shock is complex, and acid-base dysregulation has been identified as a key factor in the pathophysiology of the condition 3.
• Administration of sodium bicarbonate during cardiopulmonary resuscitation has been shown to exacerbate hypercapnia and acidosis of central venous blood and tissue in some cases 4.

Predictive Value of Bicarbonate Levels

• Baseline serum bicarbonate levels have been found to be a significant predictor of 28-day mortality in cardiogenic shock patients, with a hazard ratio of 0.93 (95% CI 0.866-0.998, P=0.046) 2.
• Patients with low serum bicarbonate levels at admission have been found to have a higher risk of mortality, with a hazard ratio of 2.06 (95% CI 1.20-3.53) for 365-day mortality 2.
• The predictive value of bicarbonate levels is supported by studies that have found associations between acidemia, lactic acidosis, and shock severity with outcomes in patients with cardiogenic shock 3.

Clinical Implications

• The findings of these studies suggest that bicarbonate levels may be a useful biomarker for identifying patients with cardiogenic shock who are at high risk of mortality 2, 3.
• Further research is needed to fully understand the relationship between bicarbonate levels and cardiogenic shock, and to determine the optimal management strategies for patients with low bicarbonate levels 5, 6.