Assessment of Right Ventricular Function With CT and Echocardiography in Patients With Severe Acute Respiratory Distress Syndrome on Extracorporeal Membrane Oxygenation.

OBJECTIVES: Changes in right ventricular size and function are frequently observed in patients with severe acute respiratory distress syndrome. The majority of patients who receive venovenous extracorporeal membrane oxygenation undergo chest CT and transthoracic echocardiography. The aims of this study were to compare the use of CT and transthoracic echocardiography to evaluate the right ventricular function and to determine the prevalence of acute cor pulmonale in this patient population. DESIGN: Observational, retrospective, single-center, cohort study. SETTING: Severe respiratory failure and extracorporeal membrane oxygenation center. PATIENTS: About 107 patients with severe acute respiratory distress syndrome managed with venovenous extracorporeal membrane oxygenation. INTERVENTIONS: Chest CT to evaluate right ventricular size and transthoracic echocardiography to evaluate right ventricular size and function. MEASUREMENTS AND MAIN RESULTS: All 107 patients had a qualitative assessment of right ventricular size and function on transthoracic echocardiography. Quantitative measurements were available in 54 patients (50%) who underwent transthoracic echocardiography and in 107 of patients (100%) who received CT. Right ventricular dilatation was defined as a right ventricle end-diastolic diameter greater than left ventricular end-diastolic diameter upon visual assessment or an right ventricle end-diastolic diameter/left ventricular end-diastolic diameter and/or right ventricle cavity area/left ventricular cavity area of greater than 0.9. Right ventricle systolic function was visually estimated as being normal or impaired (visual right ventricular systolic impairment). The right ventricle was found to be dilated in 38/107 patients (36%) and in 58/107 patients (54%), using transthoracic echocardiography or CT right ventricle end-diastolic diameter/left ventricular end-diastolic diameter, respectively. When the CT right ventricle cavity/left ventricular cavity area criterion was used, the right ventricle was dilated in 19/107 patients (18%). About 33/107 patients (31%) exhibited visual right ventricular systolic impairment. Transthoracic echocardiography right ventricle end-diastolic diameter/left ventricular end-diastolic diameter showed good agreement with CT right ventricle cavity/left ventricular cavity area (R 2 = 0.57; p < 0.01). A CT right ventricle cavity/left ventricular cavity area greater than 0.9 provided the optimal cutoff for acute cor pulmonale on transthoracic echocardiography with an AUC of 0.78. Acute cor pulmonale was defined by the presence of a right ventricle "D-shape" and quantitative right ventricle dilatation on transthoracic echocardiography or a right ventricle cavity/left ventricular cavity area greater than 0.9 on CT. A diagnosis of acute cor pulmonale was made in 9/54 (14% patients) on transthoracic echocardiography and in 19/107 (18%) on CT. CONCLUSIONS: Changes in right ventricular size and function are common in patients with severe acute respiratory distress syndrome requiring venovenous extracorporeal membrane oxygenation with up to 18% showing imaging evidence of acute cor pulmonale. A CT right ventricular cavity /left ventricular cavity area greater than 0.9 is indicative of impaired right ventricular systolic function.

A left shift in the oxyhaemoglobin dissociation curve in patients with severe coronavirus disease 2019 (COVID-19).

Critically ill patients with coronavirus disease 2019 (COVID-19) present with hypoxaemia and are mechanically ventilated to support gas exchange. We performed a retrospective, observational study of blood gas analyses (n = 3518) obtained from patients with COVID-19 to investigate changes in haemoglobin oxygen (Hb-O2 ) affinity. Calculated oxygen tension at half-saturation (p50 ) was on average (±SD) 3·3 (3·13) mmHg lower than the normal p50 value (23·4 vs. 26·7 mmHg; P < 0·0001). Compared to an unmatched historic control of patients with other causes of severe respiratory failure, patients with COVID-19 had a significantly higher Hb-O2 affinity (mean [SD] p50 23·4 [3·13] vs. 24·6 [5.4] mmHg; P < 0·0001). We hypothesise that, due to the long disease process, acclimatisation to hypoxaemia could play a role.

Veno-arterio-venous ECMO for septic cardiomyopathy: a single-centre experience.

INTRODUCTION: The role of extracorporeal support for patients with septic shock remains unclear. METHODS: We conducted a retrospective analysis of our single-centre experience with veno-arterio-venous extracorporeal membrane oxygenation (VAV ECMO) in adult patients with severe respiratory failure and septic cardiomyopathy. Clinical data was extracted from electronic medical records including a dedicated ECMO referral and follow-up database. RESULTS: Twelve patients were commenced on VAV ECMO for septic cardiomyopathy for a median of four days (IQR 3.0 to 5.3) between 01/2014 and 12/2017. Five patients (41.7%) had a cardiac arrest prior to initiation of ECMO support. At baseline, median left ventricular ejection fraction was 16.25% (IQR 13.13 to 17.5) and median PaO2/FiO2 ratio was 9 kPa (IQR 6.5 to 12.0) [67.50 mmHg (IQR 48.75 to 90.00)]. The survival rate to hospital discharge for VAV ECMO was 75% in this cohort. None of the surviving patients died within the follow-up period (median six month). CONCLUSION: VAV ECMO is a feasible rescue strategy for a small proportion of patients with combined respiratory and cardiac failure secondary to septic shock with septic cardiomyopathy. We provide a detailed report of our experience with this technique. Further research is required comparing the different extracorporeal strategies directly to conventional resuscitation and against each other.