In critically ill patients, right ventricular (RV) dysfunction is prevalent and is associated with poor prognosis. Tricuspid annular plane systolic excursion (TAPSE) is a common critical care (CCE) echocardiography measurement used to assess RV function. Imaging of myocardial deformation (using strain measurement) has been extensively investigated in cardiology and is suited for improved RV function assessment. RV strain in critically ill patients is a topic of limited study, however, and its introduction to the ICU is a relatively recent development. Therefore, this study sought to determine whether or not RV strain could be measured with tissue-Doppler imaging (TDI) in critically sick patients and to investigate the relationship between RV strain and the more traditional CCE metrics typically used to describe RV function. This research is part of the prospective observational cohorts Simple Intensive Care Studies (SICS)-I and SICS-II, but it is being conducted at a single site. Acutely hospitalised people with a 24-hour or longer anticipated ICU stay were included. In the first 24 hours after being admitted to the intensive care unit, CCE was conducted. Images of the tricuspid annulus, peak systolic velocity (RV s’), and transapical pressure gradient (TDI) were obtained from individuals undergoing CCE. Both the RV free wall longitudinal strain (RVF WSL) and the RV global 4-chamber longitudinal strain (RV4CSL) were measured offline. Researchers covered 171 patients in all. While only 62% and 56% of the samples found RVFWSL and RV4CSL to be feasible, respectively, the intra- and inter-rater reliability based on the intraclass correlation coefficient were good to exceptional when measurements were actually taken. About 56 patients (33%), based on TAPSE or RV s’, had RV dysfunction, whereas 24 patients (14%), based on RBF WSL or RV4CSL, also had RV dysfunction. While traditional measures of RV function remained unchanged, 14 patients (8%) showed diminished RVF WSL, RV4CSL, or both. The severity of their sickness was much higher in this group of patients. Consistent outcomes were also found in sensitivity analyses involving fractional area change. Despite the difficulties, good to outstanding repeatability was demonstrated for TDI RV strain imaging in critically ill patients when measurements were properly acquired. However, further research is needed to better understand the diagnostic and prognostic use of RV strain in critically sick patients, and to better balance the challenges of imaging with its potential benefits.