Correct!
1. Acute cor pulmonale likely due to ARDS
Bedside echocardiography revealed hyperdynamic left ventricular function and signs of volume and pressure overload of the RV; increased RV end-diastolic volume on subcostal four chamber view and septal flattening “D sign” on subcostal short axis view respectively, Figures 3-4.
Figure 3. Still image of Figure 1, demonstrating enlargement of the right ventricle (RV) compared to the left ventricle (LV). The RV being as large or larger than the LV is a sign of abnormal dilation. The right atrium (RA) and left atrium (LA) are also labeled.
Figure 4. Still image of Figure 2/Video 2. In the subcostal short axis view, the RV is dilated and superior, whereas the LV is small with septal flattening. The normal short axis LV is round or shaped like an “O”. In this case, the intra ventricular septum (labeled –IVS) has become flat and the LV is the shape of a “D” with the flat edge being the IVS.
Given persistent hypoxemia and evidence of RV failure, in the setting of ARDS, acute Cor Pulmonale related to ARDS was diagnosed. It should be noted the patient had a negative CT angiogram. The patient was diuresed and placed on inhaled NO to reduce RV preload and reduce RV afterload, respectively. While this resulted in temporary improvement in hypoxemia, the patient worsened the next day and the patient was placed on veno-venous extra-corporeal membrane oxygenator therapy (ECMO).
Despite improved understanding of pathophysiology of ARDS, it still carries significant mortality. It has long been known that ARDS causes, in addition to alveolar dysfunction, pulmonary capillary dysfunction leading to acute pulmonary hypertension. It is estimated that acute cor pulmonale(ACP) complicates 20-25% of ventilated patients with ARDS (1). Recent evidence suggests that “RV protective mechanical ventilation” may results in improved outcomes in patients with ARDS and ACP (1,2).
In a review by Repesse et al. (1), the authors suggest routinely performing echocardiography-assisted analysis of RV function in ARDS given high incidence of RV failure in this patient population. They go on to describe an RV-protective ventilation strategy that includes strict limitation of plateau pressure (<27 cm H2O), driving pressure (< 17 cm H2O), diminution of PEEP and control of hypercapnia (< 60 mmHg), which they argue, may also be achieved with prone ventilation.
Jawad Abukhalaf MD and Michel Boivin MD
Division of Pulmonary, Critical Care and Sleep Medicine,
University of New Mexico School of Medicine
Albuquerque, NM USA
References