The incidence of hypophosphatemia after lung transplant surgery: preliminary data from two major centers

SESSION TITLE: Transplantation Posters 3 SESSION TYPE: Original Investigation Posters PRESENTED ON: 10/10/2023 12:00 pm - 12:45 pm PURPOSE: Little is known about the incidence of hypophosphatemia after surgery in general and particularly in high-risk surgeries such as lung transplantation since phosphate is an electrolyte that is not routinely checked. Our hypothesis was that hypophosphatemia is common after lung transplantation. METHODS: This is an exploratory retrospective cohort study of lung transplant patients at two high-volume centers (University of Washington Medical Center, Seattle, WA and University of California Los Angeles Medical Center, Los Angeles, CA). Approval by the institutional review boards at each site and waiver of informed consent were obtained. Patients had phosphate and lactate levels measured within 6 hours after admission to the intensive care unit were included. Normal serum phosphate was defined as phosphate level >= 2.5 and <= 4.5 mg/dL. Severe lactic acidosis was defined as lactate level > 4 mmol/L. We also extracted patient demographic and procedural variables. RESULTS: A total of 556 lung transplant patients were included. There were 154/556 (28%) patients in the hypophosphatemia (phosphate < 2.5 mg/dL), 318/556 (38%) in the normal phosphate (phosphate >= 2.5 and <= 4.5 mg/dL) and 84/556 (15%) in hyperphosphatemia (phosphate > 4.5 md/dL) group. Sixteen (2.9%) patients had phosphate levels below 1 mg/dL which is considered severely hypophosphatemic. Mean postoperative lactate was 4.7 mmol/L in hypophosphatemia group, 4.3 mmol/L in normal phosphate group, and 6.4 mmol/L in hyperphosphatemia group. The incidence of severe lactic acidosis was 49% in hypophosphatemia group, 42% in normal phosphate group, and 62% in hyperphosphatemia group. CONCLUSIONS: The incidence of postoperative hypophosphatemia after lung transplantation was common in this cohort. Although the incidence of severe hypophosphatemia was not as common, it is notable that 3% of patients had severe hypophosphatemia. This is higher than what we previously described in non-transplant heart surgeries; 18.6% and 10.8% incidence of hypo- and hyperphosphatemia, respectively. We also observed higher mean lactate levels and higher incidence of severe lactic acidosis in hypo- and hyperphosphatemia groups. Phosphate is essential element for liver’s ability to metabolize lactate and may play a role in lactic acidosis. CLINICAL IMPLICATIONS: Postoperative hypophosphatemia after lung transplantation appears to be common. Effects of postoperative hypophosphatemia on outcomes are unknown. DISCLOSURES: No relevant relationships by Drew Cheng No relevant relationships by Srdjan Jelacic No relevant relationships by Wolf Kratzert No relevant relationships by Nicole Mostofi No relevant relationships by Michael Mulligan No relevant relationships by Jennifer Scovotti No relevant relationships by Dominik Steck No relevant relationships by Kyle Tillinghast No relevant relationships by Kei Togashi No relevant relationships by David Wu