In recent years, significant advancements have been made in understanding and describing the pathogenesis of metabolic acidosis during cardiopulmonary bypass (CPB) procedures. One study that sheds light on this topic is the research article titled “The aetiology and pathogenesis of cardiopulmonary bypass-associated metabolic acidosis using polygeline pump prime”. Published in 2023, this study delves into the factors contributing to metabolic acidosis during CPB, specifically focusing on the use of polygeline as a pump prime.
What is the Pathogenesis of Cardiopulmonary Bypass-Associated Metabolic Acidosis using Polygeline Pump Prime?
The pathogenesis, or underlying mechanism, of metabolic acidosis during cardiopulmonary bypass with polygeline pump prime has been a subject of ongoing research and investigation. This study aims to provide a clearer understanding of this phenomenon through the use of new quantitative methods in assessing acid-base balance.
The research was conducted as a prospective cohort study at a tertiary institution, involving 10 patients undergoing cardiac bypass graft surgery. The key objective was to analyze acid-base changes throughout different stages of CPB using polygeline as a pump prime, and to quantify the factors contributing to the development of metabolic acidosis.
What are the Contributing Factors to Metabolic Acidosis during Cardiopulmonary Bypass?
During the study, arterial blood samples were taken at four time intervals: post-induction, on CPB during cooling and rewarming, and at skin closure. Several measurements were analyzed, including serum concentrations of sodium, potassium, magnesium, calcium, chloride, bicarbonate, and phosphate, as well as arterial blood gases, and serum albumin, lactate, and pyruvate concentrations.
Results revealed that all patients developed a mild metabolic acidosis during CPB. The median serum standard bicarbonate concentration decreased from 25.0 mEq/l post-induction to 22.3 mEq/l at cooling and 22.2 mEq/l at rewarming. Similarly, the standard base excess decreased from a median of 1.55 mEq/l prior to CPB to -2.50 mEq/l at cooling, -1.65 mEq/l at rewarming, and -0.85 mEq/l at skin closure.
Surprisingly, this metabolic acidosis occurred despite a decrease in median serum lactate concentration from 3.20 mEq/l post-induction to 1.83 mEq/l, 1.80 mEq/l, and 1.58 mEq/l at the subsequent time points. The main cause of acidosis was identified as an increase in median serum chloride concentration from 104.9 mEq/l post-induction to 111.0 mEq/l during CPB, with a gradual decrease afterwards. Further analysis indicated a significant increase in the strong ion gap (SIG), relating to unmeasured anions such as polygeline.
How does Polygeline Pump Prime Affect Acid-Base Balance during Cardiopulmonary Bypass?
Polygeline is a synthetic colloid commonly used as a pump prime during CPB procedures. The findings of this study demonstrate that using polygeline as the pump prime contributes to the development of metabolic acidosis during CPB. The increase in serum chloride concentration, coupled with the presence of unmeasured anions like polygeline, plays a significant role in the acid-base imbalance.
In simpler terms, the study showed that when polygeline is used as a pump prime, it causes an increase in serum chloride levels. This rise in chloride concentration is a key factor in the development of metabolic acidosis. Additionally, the presence of unmeasured anions, including polygeline itself, contributes to the acidosis.
It’s important to note that the study also highlighted the partial attenuation of acidosis by iatrogenic hypoalbuminemia, which refers to a decrease in albumin levels due to medical intervention.
Exploring the Implications
This groundbreaking research article sheds light on the specific factors that contribute to metabolic acidosis in patients undergoing cardiopulmonary bypass procedures. By utilizing quantitative physicochemical principles, the study shows how the use of polygeline as a pump prime can cause metabolic acidosis, primarily due to the increase in serum chloride concentration and the presence of unmeasured anions like polygeline.
Understanding the underlying causes of metabolic acidosis during CPB is essential for improving patient outcomes. This research helps clinicians and medical professionals gain insights into the importance of carefully considering the choice of pump prime in cardiac surgery. By selecting alternative pump primes or optimizing their usage, healthcare providers can potentially mitigate the risk of metabolic acidosis and its associated complications.
Moreover, this study highlights the significance of ongoing research in the field of acid-base balance and metabolic abnormalities. Continued advancements in quantitative biophysical methods allow for a more comprehensive understanding of complex physiological processes.
Takeaways
The research article on the aetiology and pathogenesis of cardiopulmonary bypass-associated metabolic acidosis with polygeline pump prime provides valuable insights into the previously unclear topic. It demonstrates that in patients receiving a chloride-rich and polygeline-based pump prime during CPB, the development of metabolic acidosis is primarily influenced by iatrogenic (medically-induced) increases in serum chloride concentration and unmeasured strong anions (SIG).
These findings serve as an important reference for medical professionals involved in cardiac bypass graft surgeries, helping them make informed decisions regarding pump prime selection and management of acid-base balance. Further research on this subject will likely contribute to the refinement of CPB techniques and the improvement of patient outcomes.