Unexplained hemolysis in patients undergoing ECMO: beware of hypertriglyceridemia

Evaluation of Hypertriglyceridemia in Critically Ill Patients With Coronavirus Disease 2019 Receiving Propofol

Objectives

To report the prevalence of, and evaluate risk factors for, the development of hypertriglyceridemia (defined as a serum triglyceride level of > 400 mg/dL) in patients with coronavirus disease 2019 who received propofol.

Design

Single-center, retrospective, observational analysis.

Setting

Brigham and Women's Hospital, a tertiary academic medical center in Boston, MA.

Patients

All ICU patients who with coronavirus disease 19 who received propofol between March 1, 2020, and April 20, 2020.

Interventions

None.

Measurements and Main Results

The major outcome of this analysis was to report the prevalence of, and risk factors for, the development of hypertriglyceridemia in patients with coronavirus disease 19 who received propofol. Minor outcomes included the development of acute pancreatitis and description of propofol metrics. Of the 106 patients that were included, 60 (56.6%) developed hypertriglyceridemia, with a median time to development of 46 hours. A total of five patients had clinical suspicion of acute pancreatitis, with one patient having confirmatory imaging. There was no difference in the dose or duration of propofol in patients who developed hypertriglyceridemia compared with those who did not. In the patients who developed hypertriglyceridemia, 35 patients (58.5%) continued receiving propofol for a median duration of 105 hours. Patients who developed hypertriglyceridemia had elevated levels of inflammatory markers.

Conclusions

Hypertriglyceridemia was commonly observed in critically ill patients with coronavirus disease 2019 who received propofol. Neither the cumulative dose nor duration of propofol were identified as a risk factor for the development of hypertriglyceridemia. Due to the incidence of hypertriglyceridemia in this patient population, monitoring of serum triglyceride levels should be done frequently in patients who require more than 24 hours of propofol. Many patients who developed hypertriglyceridemia were able to continue propofol in our analysis after reducing the dose.

ECMO Membrane Lung Failure due to Hypertriglyceridemia: A Case Report and Review of the Literature

The deleterious effects of high serum lipid content on the membrane lung (ML) during extracorporeal membrane oxygenation (ECMO) are sparsely documented, and the threshold of lipemia-induced membrane failure is poorly described. We present a case of a patient on venovenous ECMO who developed ML failure after 7 days due to moderate to severe hypertriglyceridemia (700-800 mg/dL). ML failure was exhibited by impaired gas exchange and high transmembrane pressures, and there was notable lipemic layering in the circuit immediately after decannulation. This case demonstrates that in addition to patients with extreme lipemia, ML failure can also occur in patients with moderate to severe hypertriglyceridemia. Hypertriglyceridemia should be suspected in patients with high transmembrane pressures and ML failure not attributable to thrombosis, and these patients may require frequent ML changes if a prolonged ECMO run is required.

Hemolysis and Plasma Free Hemoglobin During Extracorporeal Membrane Oxygenation Support: From Clinical Implications to Laboratory Details

Venovenous and venoarterial extracorporeal membrane oxygenation (ECMO) are lifesaving supports that are more and more frequently used in critically ill patients. Despite of major technological improvements observed during the last 20 years, ECMO-associated hemolysis is still a complication that may arise during such therapy. Hemolysis severity, directly appreciated by plasma free hemoglobin concentration, may be present with various intensity, from a nonalarming and tolerable hemolysis to a highly toxic one. Here, we propose a review dedicated to extracorporeal membrane oxygenation (ECMO)-associated hemolysis, with a particular emphasis on pathophysiology, prevalence, and clinical consequences of such complication. We also focus on laboratory assessment of hemolysis and on the limits that have to be known by clinicians to prevent and manage hemolytic events.

Frequency and causes of lipemia interference of clinical chemistry laboratory tests

Objectives

The aims of this study were to identify the causes of severe lipemia in an academic medical center patient population and to determine the relationship between lipemia and hemolysis.

Design and methods

Retrospective study was done on the data from the core clinical laboratory at an academic medical center. Lipemic indices were available for all chemistry specimens analyzed over a 16-month period (n=552,029 specimens) and for serum/plasma triglycerides concentrations ordered for clinical purposes over a 16-year period (n=393,085 specimens). Analysis was performed on Roche Diagnostics cobas 8000 analyzers. Extensive chart review was done for all specimens with lipemic index greater than 500 (severely lipemic) and for all specimens with serum/plasma triglycerides greater than 2000 mg/dL. We also determined the relationship between lipemia and hemolysis.

Results

The most frequent suspected causes of very high lipemic index (>500) were found to be lipid-containing intravenous infusions (54.4% of total; fat emulsions for parenteral nutrition – 47%; propofol −7.4%) and diabetes mellitus (25% of total, mainly type 2). The most frequent suspected causes of very elevated serum/plasma triglycerides (>2000 mg/dL) was diabetes mellitus (64%, mainly type 2) and hyperlipidemia (16.9%). The frequency of hemolysis increased with increasing lipemic index.

Conclusions

Intravenous lipid infusions and type 2 diabetes were the most common causes of severe lipemia in this study at an academic medical center. Given that iatrogenic factors are the most common cause of severe lipemia, education and intervention may be helpful in reducing frequency of severe lipemia in patient specimens.

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Intravenous lipids and type 2 diabetes were most common causes of severe lipemia.

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The frequency of hemolysis increased with increasing lipemic index.

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Diabetes type 2 was the most common cause of extreme hypertriglyceridemia.

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Education and intervention may be helpful in reducing frequency of lipemia.