Authors: Steck DT et al.
Journal of Clinical Anesthesia, 2026, article number 112157
Summary:
This multicenter retrospective cohort study evaluated the incidence of phosphate abnormalities following cardiac surgery requiring cardiopulmonary bypass and their relationship to postoperative lactic acidosis. Prior data on this topic were limited to single-center experiences, prompting the authors to analyze a large dataset from the Multicenter Perioperative Outcomes Group.
The study included 34,953 adult patients who had both phosphate and lactate levels measured within six hours after surgery. The investigators categorized patients into hypophosphatemia, normophosphatemia, and hyperphosphatemia groups, and assessed the association of these abnormalities with severe lactic acidosis, defined as lactate ≥4.0 mmol/L.
Phosphate abnormalities were common in the early postoperative period. Hypophosphatemia occurred in 20% of patients, while 14% developed hyperphosphatemia. After adjusting for confounders, both low and high phosphate levels were independently associated with increased odds of severe lactic acidosis. Hypophosphatemia carried an odds ratio of 1.46, while hyperphosphatemia had an odds ratio of 1.30 compared to patients with normal phosphate levels. Notably, severe hypophosphatemia (phosphate <1.0 mg/dL) was associated with a markedly higher risk, with an odds ratio of 2.53 in non-transplant patients.
These findings suggest that phosphate derangements are not only frequent after cardiopulmonary bypass but also clinically relevant, as they correlate with impaired metabolic recovery reflected by elevated lactate levels. The relationship likely reflects underlying physiologic stress, altered cellular metabolism, and impaired ATP generation, particularly in hypophosphatemic states.
The authors conclude that routine assessment of phosphate levels in the immediate postoperative period may be warranted, as early identification of abnormalities could help identify patients at higher risk for metabolic complications such as severe lactic acidosis.
What You Should Know:
Phosphate abnormalities after cardiac surgery are common and often overlooked. Both hypophosphatemia and hyperphosphatemia are associated with increased risk of severe lactic acidosis, suggesting they are important markers of metabolic stress. Severe hypophosphatemia carries the highest risk and may reflect impaired cellular energy production. Monitoring phosphate levels early after surgery may help identify high-risk patients and guide more targeted postoperative management.
Key Points:
- 34,953 cardiac surgery patients analyzed across 45 centers
- Hypophosphatemia occurred in 20%; hyperphosphatemia in 14%
- Both abnormalities independently increased risk of severe lactic acidosis
- Severe hypophosphatemia showed the strongest association (OR 2.53)
- Early postoperative phosphate monitoring may improve risk stratification
Thank you to the Journal of Clinical Anesthesia for allowing us to review and summarize this article.