Clinical risk score for the diagnosis of acute cor pulmonale in acute respiratory distress syndrome

Abstract

Context Acute cor pulmonale (ACP) is a common sequela in patients with acute respiratory distress syndrome (ARDS) and represents the most severe presentation of right ventricular dysfunction, secondary to pulmonary vascular dysfunction. Although most previous studies adopted transesophageal echocardiography in the diagnosis of ACP in patients with ARDS, transthoracic echocardiography (TTE) appears as a promising alternative, being noninvasive and more available with continuously improving expertise in its use by ICU physicians. Aims Our study aimed to test the accuracy of ACP risk score by TTE. Settings and design This is a prospective observational cross-sectional study that was carried out over 6 months in our department. Patients and methods Our study was carried out on 45 mechanically ventilated patients with ARDS, who had been subjected to lung-protective approach. TTE was performed within the first 72 h of ARDS diagnosis. ACP was diagnosed when the ratio of right ventricular/left ventricular end-diastolic area more than 0.6 on parasternal short-axis view or apical four chambers view associated with interventricular septum dyskinesia in a parasternal short-axis or long-axis view at end-systole. ACP risk score parameters were checked and scored; (one point for each parameter). It consisted of pneumonia, hypercapnia arterial carbon dioxide tension of at least 48 mmHg, driving pressure of at least 18 cmH2O, and arterial oxygen tension/fractional inspired oxygen less than 150 mmHg. Qualitative data were described using number and percentage. Quantitative data were described using mean and SD, median, minimum and maximum. Comparison between different groups’ variables had been tested using χ2-test. Receiver operating characteristic curve expressed a recommended cutoff. The area under the receiver operating characteristic curve denotes the diagnostic performance of the test. Area of significance of the obtained results was judged at the 5% level (P<0.05). Results ACP risk score showed high sensitivity (100%), average specificity (51.43%), and good overall accuracy (62.2%) when score of at least 2 was used as a cutoff value. Hypercapnia, pneumonia, hypoxia, high plateau pressure, and positive end-expiratory pressure were associated with increased ACP incidence in patients with ARDS. Conclusion ACP risk score is a highly sensitive score in predicting and diagnosing ACP in patients with ARDS.