ARDS is a major public health problem in critically ill patients,with an incidence between 16%–18% of all ventilated patients in the ICU, and a mortality rate of 30–40%.We sought to determine if elevated cardiac biomarkers could be used as a prognostic indicator for mortality&morbidity in ARDS.
Retrospective analysis of ICU-patients diagnosed with ARDS according to ATS/ERS guidelines, who had at least 48-hours ICU stay, at least one cardiac biomarker measured, and did not have chronic lung disease, previous acute-MI during the same admission, and previous palliative care orders. Charts were reviewed for demographics, admission diagnosis, CKMBI, cTnI, outcome, ICU-length of stay, number of ventilator-days and number of organ-dysfunctions. Sample was divided into four groups: NCB–Normal Cardiac-Biomarkers, EcTnI–elevated cardiac Troponin-I( > 0.59ng/mL), ECKMBI–Elevated CKMB index ( > 5, with-CK > 200), and ECB–Elevated Cardiac Biomarkers (any one of cTnI or CKMBI). The groups were then compared for mortality and morbidity indicators.
51 ARDS patients met the criteria. They were all African-American (100%), 28 females (55%). Mean age was=62.3, mean ICU-length of stay in days was=18.4, mean ventilator-days: 15.2, and mean number of organ-dysfunctions was=1.6. 22 patients died (43%). Cardiac biomarkers were normal in 30 subjects (59%) (NCB group) and were elevated in 21 (41%) (ECB group). 15 subjects (29%) had elevated CKMB index (ECKMBI group) and 21 (41%) had elevated troponin (EcTnI group). For EcTnI and ECB groups: mortality, ICU length of stay, number of ventilator days, and number of organ dysfunction were: 42.8%, 17.1, 15.2 and 2, compared to 43.3%, 19.4, 15.2 and 1.4 for normal cTnI and NCB group (p-values 0.973, 0.443, 0.998 and 0.081 respectively). Analyzing CKMB index, the ECKMBI group had mortality, ICU length of stay, number of ventilator days, and number of organ dysfunction 46.6%, 17.9, 16 and 1.9 compared to 41.6%, 18.6, 14.7 and 1.5 for normal CKMB index (p-values 0.742, 0.826, 0.459 and 0.208 respectively).
Our study showed no statistically significant correlation between elevated cardiac biomarkers and mortality or morbidity in ARDS, therefore elevated cTnI or CKMB index do not reflect an increased risk of death or prolonged hospitalization in ICU.
Cardiac biomarkers cannot be used as a prognostic indicator in patients with ARDS.
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