Right ventricular (RV) dysfunction is common in critically ill patients.1–3 It is associated with multiple clinical scenarios frequently encountered by the intensivist, including acute cor pulmonale (ACP), acute RV dysfunction of sepsis, and acute RV infarction. In addition, the assessment of RV function is essential for the determination of a patient’s preload responsiveness. Echocardiography is the best available method to diagnose and monitor RV function at the bedside, as it provides the intensivist with a prompt, accurate, noninvasive, and serial method to monitor the function of the right heart and its response to different interventions. This chapter describes a variety of echocardiographic methods to assess RV function that are particularly relevant to critical care practice for both the basic and advanced critical care echocardiographer. While the assessment of RV function in the noncritically ill patient is beyond the purview of this chapter, the techniques described here are also applicable to the assessment of RV function in the ambulatory patient.
This chapter is designed to have utility for intensivists with basic critical care echocardiography (CCE) skills. In this case, the examination is limited to the standard twodimensional (2D) five view approach (see Chapter 6), which focuses on a qualitative visual estimate of RV size and septal dynamics. This approach is a key component of the rapid evaluation of hemodynamic failure.
In addition, this chapter reviews the evaluation of RV function using methods that are relevant only to the intensivist with skill at advanced critical care echocardiography. By definition, these include Doppler-based measurements that are not part of basic CCE. Given the time constraints of bedside scanning in a busy intensive care unit, the discussion will focus on a limited number of methods rather than listing all of the possible methods for evaluation of RV function that are available to the advanced level echocardiographer.
Normal RV Anatomy and Function
The RV comprises two anatomically and functionally distinct cavities separated by the crista supraventricularis: an inflow region (the sinus) and an outflow tract (the cone or infundibulum). The tricuspid valve (TV) and its apparatus plus heavily trabeculated myocardium form the sinus. Smooth myocardium and the pulmonic valve form the infundibulum. The sinus generates pressure during systole while the infundibulum modulates this pressure and prolongs its duration. RV contraction occurs serially in three different phases: (a) contraction of the sinus along its longitudinal axis, (b) radial contraction of the RV free wall toward the interventricular septum (IVS), and (c) torsion of the left ventricle (LV) (clockwise rotation of the LV base with counterclockwise rotation of apex) pulling the RV in similar manner. Overall, LV contraction contributes 25% of its own stroke work to the generation of RV stroke work via the IVS.4
The normal RV is less muscular than the LV and has a free wall thickness that measures 3–4 mm. As a ...