Bedside assessment of left atrial pressure in critical care: a multifaceted gem.

Evaluating left atrial pressure (LAP) solely from the left ventricular preload perspective is a restrained approach. Accurate assessment of LAP is particularly relevant when pulmonary congestion and/or right heart dysfunction are present since it is the pressure most closely related to pulmonary venous pressure and thus pulmonary haemodynamic load. Amalgamation of LAP measurement into assessment of the 'transpulmonary circuit' may have a particular role in differentiating cardiac failure phenotypes in critical care. Most of the literature in this area involves cardiology patients, and gaps of knowledge in application to the bedside of the critically ill patient remain significant. Explored in this review is an overview of left atrial physiology, invasive and non-invasive methods of LAP measurement and their potential clinical application.

Right ventricular outflow tract Doppler flow analysis and pulmonary arterial coupling by transthoracic echocardiography in sepsis: a retrospective exploratory study.

INTRODUCTION: Right ventricular (RV) and pulmonary vascular dysfunction appear to be common in sepsis. RV performance is frequently assessed in isolation, yet its close relationship to afterload means combined analysis with right ventricular outflow tract (RVOT) Doppler and RV-pulmonary arterial (RV-PA) coupling may be more informative than standard assessment techniques. Data on feasibility and utility of these parameters in sepsis are lacking and were explored in this study. METHODS: This is a retrospective study over a 3-year period of one-hundred and thirty-one patients admitted to ICU with sepsis who underwent transthoracic echocardiography (TTE) with RVOT pulsed wave Doppler. RVOT Doppler flow and RV-PA coupling was evaluated alongside standard measurements of RV systolic function and pulmonary pressures. RVOT Doppler analysis included assessment of pulmonary artery acceleration time (PAAT), velocity time integral and presence of notching. RV-PA coupling was assessed using tricuspid annular planar systolic excursion/pulmonary artery systolic pressure (TAPSE/PASP) ratio. RESULTS: PAAT was measurable in 106 (81%) patients, and TAPSE/PASP was measurable in 77 (73%). Seventy-three (69%) patients had a PAAT of ≤ 100 ms suggesting raised pulmonary vascular resistance (PVR) is common. RVOT flow notching occurred in 15 (14%) of patients. TRV was unable to be assessed in 24 (23%) patients where measurement of PAAT was possible. RV dysfunction (RVD) was present in 28 (26%), 26 (25%) and 36 (34%) patients if subjective assessment, TAPSE < 17 mm and RV dilatation definitions were used, respectively. There was a trend towards shorter PAAT with increasing severity of RVD. RV-PA uncoupling defined as a TAPSE/PASP < 0.31 mm/mmHg was present in 15 (19%) patients. As RV dilatation increased the RV-PA coupling ratio decreased independent of LV systolic function, whereas TAPSE appeared to be more susceptible to changes in LV systolic function. CONCLUSION: Raised PVR and RV-PA uncoupling is seen in a significant proportion of patients with sepsis. Non-invasive assessment with TTE is feasible. The role of these parameters in assisting improved definitions of RVD, as well as their therapeutic and prognostic utility against standard parameters, deserves further investigation.