Thyroid function in mechanically ventilated patients with acute respiratory failure: Prognostic value and its relation to high-sensitivity C-reactive protein

IntroductionThyroid dysfunction may occur in patients with acute respiratory failure (ARF) and may influence the prognosis.ObjectivesTo assess the prognostic value of thyroid hormones in mechanically ventilated patients due to pulmonary diseases. Also to find out a possible association with high sensitivity C-reactive protein (hs-CRP) being not only a measure of overall systemic inflammation, but also a major determinant of hospitalization and death risk.MethodsForty patients, who were admitted at the respiratory intensive care unit (RICU) at Kasr El-Aini Hospital, were enrolled. Invasive mechanical ventilation (IMV) was applied to 24 patients and non-invasive ventilation (NIV) was initially applied to 16 patients. Six patients required subsequent IMV. Measurement of ABG, APACHE II score calculation, and measurement of serum level of hs-CRP, Free T3, Free T4, and TSH were done. Patients’ outcome was assessed.ResultsFifteen patients (37.5%) had normal thyroid state on admission and 16 patients (40%) had non thyroidal illness syndrome (NTIS). No significant difference was observed between the levels of thyroid hormones and; APACHE II score, type and duration of mechanical ventilation, and ICU stay. Also, there was no significant difference between patients who succeeded NIV and those who failed it, and between survivors and non-survivors. A significant positive correlation between TSH level and hs-CRP was found.ConclusionThe study supports the presence of thyroid hormone changes in ARF; however their levels neither significantly predict the success of NIV nor predict mortality. The possible link between hs-CRP and TSH level warrants further evaluation, especially in patients with prolonged mechanical ventilation.