Peripheral microcirculatory alterations are associated with the severity of acute respiratory distress syndrome in COVID-19 patients admitted to intermediate respiratory and intensive care units.

BACKGROUND: COVID-19 is primarily a respiratory disease; however, there is also evidence that it causes endothelial damage in the microvasculature of several organs. The aim of the present study is to characterize in vivo the microvascular reactivity in peripheral skeletal muscle of severe COVID-19 patients. METHODS: This is a prospective observational study carried out in Spain, Mexico and Brazil. Healthy subjects and severe COVID-19 patients admitted to the intermediate respiratory (IRCU) and intensive care units (ICU) due to hypoxemia were studied. Local tissue/blood oxygen saturation (StO2) and local hemoglobin concentration (THC) were non-invasively measured on the forearm by near-infrared spectroscopy (NIRS). A vascular occlusion test (VOT), a three-minute induced ischemia, was performed in order to obtain dynamic StO2 parameters: deoxygenation rate (DeO2), reoxygenation rate (ReO2), and hyperemic response (HAUC). In COVID-19 patients, the severity of ARDS was evaluated by the ratio between peripheral arterial oxygen saturation (SpO2) and the fraction of inspired oxygen (FiO2) (SF ratio). RESULTS: Healthy controls (32) and COVID-19 patients (73) were studied. Baseline StO2 and THC did not differ between the two groups. Dynamic VOT-derived parameters were significantly impaired in COVID-19 patients showing lower metabolic rate (DeO2) and diminished endothelial reactivity. At enrollment, most COVID-19 patients were receiving invasive mechanical ventilation (MV) (53%) or high-flow nasal cannula support (32%). Patients on MV were also receiving sedative agents (100%) and vasopressors (29%). Baseline StO2 and DeO2 negatively correlated with SF ratio, while ReO2 showed a positive correlation with SF ratio. There were significant differences in baseline StO2 and ReO2 among the different ARDS groups according to SF ratio, but not among different respiratory support therapies. CONCLUSION: Patients with severe COVID-19 show systemic microcirculatory alterations suggestive of endothelial dysfunction, and these alterations are associated with the severity of ARDS. Further evaluation is needed to determine whether these observations have prognostic implications. These results represent interim findings of the ongoing HEMOCOVID-19 trial. Trial registration ClinicalTrials.gov NCT04689477 . Retrospectively registered 30 December 2020.

Impact of 6% Starch 130/0.4 and 4% Gelatin Infusion on Kidney Function in Living-Donor Liver Transplantation.

BACKGROUND: Since the first liver transplantation, pretransplantation or post-transplantation renal problems are still among the main causes of mortality and morbidity. The aim of this study was to evaluate the effects of fluid replacement solutions used intraoperatively on renal functions in elective living-donor liver transplantation. METHODS: After Ethics Committee approval, informed consents were obtained from patients. Patients with normal renal functions and scheduled for elective living-donor-liver transplantation were included in the study. Patients were randomly allocated to infusion with 6% hydroxyehylstarch 130/40 (HES group) and 4% Gelofusine (GEL group). Blood samples were obtained before the induction of anesthesia (baseline), at the end of the operation, and postoperative days 1 and 4. Different estimated glomerular filtration rate (eGFR) formulas using creatinine (modification of renal disease, chronic kidney disease-epidemiology collaboration and Cockraud Gault) were used to calculate the eGFR. RESULTS: Thirty-six patients were included in the study (GEL group = 18; HES group = 18). Patient characteristics, modified end stage liver disease-Child Pugh score, American Society of anaesthesiologist scores, and intraoperative data were similar between groups. Postoperative measurements showed that creatinine was significantly higher in the GEL group compared with the baseline, which was not the case for the HES group. Similarly, postoperative eGFR levels, as measured using MDRD and CKD-EPI, were found to be significantly lower in the GEL group. Postoperative urine albumin:creatinine ratios were significantly higher in the GEL group compared with baseline. Total crystalloid amount used, colloid, blood, fresh frozen plasma values, extubation, and intensive care unit (ICU) and hospital stay were similar in both groups. Postreperfusion syndrome developed in 6 patients in each group. CONCLUSION: In conclusion, Gelofusine seem to cause more impairment in renal functions in elective living-donor liver transplantation.

Methylene blue decreases ischemia-reperfusion (I/R)-induced spinal cord injury: an in vivo study in an I/R rabbit model.

OBJECTIVES: To evaluate the effects of intravenous methylene blue (MB) administration on ischemia-reperfusion (I/R) injury of the spinal cord (SC). METHODS: 16 rabbits were randomly assigned either to group M (n = 8; receiving MB, intervention group) or group C (n = 8; control group) and underwent a 30-min period of SC ischemia by clamping the abdominal aorta between the left renal artery and the aortic bifurcation. 15 min before clamping, rabbits received either intravenous MB (10 mg/kg; group M) or normal saline (group C). The two groups were compared 24 h postoperatively both histologically and for neurological function, using a Tarlov score. Measurements to determine levels of malondialdehyde (MDA) and glutathione (GSH) in the SC tissue were also performed. RESULTS: Neurological impairment and spinal tissue MDA levels were significantly lower in animals treated with MB (p < 0.001). In contrast, spinal GSH levels were significantly higher in group M (p < 0.001). Histological examination revealed that the integrity of the SC was better preserved in the MB group, whereas cords from the control group exhibited evidence of acute neuronal injury. CONCLUSIONS: The prophylactic use of MB reduces neurological injury and improves clinical outcomes in the rabbit SC I/R model. These effects are probably mediated by the drug's antioxidant properties.