Preoperative cerebral and renal oxygen saturation and clinical outcomes in pediatric patients with congenital heart disease.

We examined the predictability of preoperative cerebral and renal rSO2 values for outcomes in pediatric patients undergoing cardiac surgery under cardiopulmonary bypass (CPB). Patients who underwent pediatric cardiac surgery under CPB between September 2015 and September 2017 were enrolled in this study. Patients monitored with both cerebral and renal rSO2 at the beginning of surgery were included. The primary outcome was the prediction of outcomes after pediatric cardiac surgery. Outcome was defined as any of: (1) death within 30 days after surgery, or the need for (2) renal replacement therapy or (3) extracorporeal membrane oxygenation, (4) shorten mechanical ventilator-free day,(5) shorten ICU-free survival day. We included 59 patients: cyanotic n = 31; non-cyanotic n = 28. Among all patients, 15 (25%) had poor outcomes, including three deaths. The cerebral and renal rSO2 values were significantly lower in the cyanotic patients with poor outcomes compared to those without poor outcomes (cerebral: 59 ± 11 vs. 50 ± 5, p = 0.021; renal: 59 ± 15 vs. 51 ± 14, p = 0.015) but only the renal rSO2 value was significantly lower in the non-cyanotic patients (77 ± 10 vs. 61 ± 14, p = 0.011). The cut-off value (51%) of cerebral rSO2 were associated with risk of mechanical ventilator-free day and ICU-free survival day [ORs of 22.8 (95% CI 2.21-235.0, p = 0.0087) and 15.8 (95% CI 1.53-164.0, p = 0.0204), respectively] in the cyanotic patients. The cut-off value (66%) of cerebral rSO2 value was associated with risk of mechanical ventilator-free day [OR of 11.3 (95% CI 1.05-25.3, p = 0.0456)] and the cut-off value (66%) of renal rSO2 value was associated with risk of ICU-free survival day [ORs of 33.0 (95% CI 2.25-484.0, p = 0.0107)] in the noncyanotic patients. The preoperative low rSO2 values were associated with outcomes including 30-day mortality and might be reflective of the severity of cardiopulmonary function. Further studies are needed to confirm our results.

Environmental high-voltage S/TEM combined with a quadrupole mass spectrometer for concurrent in situ structural characterization and detection of product gas molecules associated with chemical reactions.

We introduce herein a combined environmental high-voltage electron microscope and a quadrupole mass spectrometer to detect product gas species associated with chemical reactions occurring in the microscope, which allows new operando experiments of, for instance, observing catalytic reactions by concurrent high-resolution transmission electron microscope (TEM) observation. We demonstrate the preliminary results of redox reactions, where the product gas species are unambiguously detected, associated with the expected structural transformations observed with TEM.

A simple biofuel cell cathode with human red blood cells as electrocatalysts for oxygen reduction reaction.

A red blood cell (RBC) from human exhibited direct electron transfer (DET) activity on a bare indium tin oxide (ITO) electrode. A formal potential of -0.152 V vs. a silver-silver chloride saturated potassium chloride (Ag|AgCl|KCl(satd.)) was estimated for the human RBC (type AB) from a pair of redox peaks at around 0.089 and -0.215 V (vs. Ag|AgCl|KCl(satd.)) on cyclic voltammetric (CV) measurements in a phosphate buffered saline (PBS; 39 mM; pH 7.4) solution. The results agreed well with those of a redox couple for iron-bearing heme groups in hemoglobin molecules (HbFe(II)/HbFe(III)) on the bare ITO electrodes, indicated that DET active species were hemoglobin (Hb) molecules encapsulated by a phospholipid bilayer membrane of the human RBC. The quantity of electrochemically active Hb in the human RBC was estimated to be 30 pmol cm(-2). In addition, the human RBC exhibited oxygen reduction reaction (ORR) activity in the dioxygen (O2) saturated PBS solution at the negative potential from ca. -0.15 V (vs. Ag|AgCl|KCl(satd.)). A single cell test proved that a biofuel cell (BFC) with an O2|RBC|ITO cathode showed the open-circuit voltage (OCV) of ca. 0.43 V and the maximum power density of ca. 0.68 µW cm(-2).