Novel transcutaneous sensor combining optical tcPO2 and electrochemical tcPCO2 monitoring with reflectance pulse oximetry

This study investigated the accuracy, drift, and clinical usefulness of a new optical transcutaneous oxygen tension (tcPO2) measuring technique, combined with a conventional electrochemical transcutaneous carbon dioxide (tcPCO2) measurement and reflectance pulse oximetry in the novel transcutaneous OxiVenT™ Sensor. In vitro gas studies were performed to measure accuracy and drift of tcPO2 and tcPCO2. Clinical usefulness for tcPO2 and tcPCO2 monitoring was assessed in neonates. In healthy adult volunteers, measured oxygen saturation values (SpO2) were compared with arterially sampled oxygen saturation values (SaO2) during controlled hypoxemia. In vitro correlation and agreement with gas mixtures of tcPO2 (r = 0.999, bias 3.0 mm Hg, limits of agreement − 6.6 to 4.9 mm Hg) and tcPCO2 (r = 0.999, bias 0.8 mm Hg, limits of agreement − 0.7 to 2.2 mm Hg) were excellent. In vitro drift was negligible for tcPO2 (0.30 (0.63 SD) mm Hg/24 h) and highly acceptable for tcPCO2 (− 2.53 (1.04 SD) mm Hg/12 h). Clinical use in neonates showed good usability and feasibility. SpO2-SaO2 correlation (r = 0.979) and agreement (bias 0.13%, limits of agreement − 3.95 to 4.21%) in healthy adult volunteers were excellent. The investigated combined tcPO2, tcPCO2, and SpO2 sensor with a new oxygen fluorescence quenching technique is clinically usable and provides good overall accuracy and negligible tcPO2 drift. Accurate and low-drift tcPO2 monitoring offers improved measurement validity for long-term monitoring of blood and tissue oxygenation. [Figure not available: see fulltext.]

Revised Day Month Year

We present measurements and theoretical interpretation of the magnetic field dependent excitation spectra of a two-electron quantum dot. The quantum dot is based on an AlxGa1−xAs parabolic quantum well with effective g ⋆-factor close to zero. Results of tunneling spectroscopy of the four lowest states are compared to exact diagonalization calculations and a generalized Heitler–London approximation and good agreement is found. Electronic correlations, associated with the formation of an H2-type Wigner molecule, turn out to be very important in this system

Impact of early haemodynamic goal-directed therapy in patients undergoing emergency surgery: an open prospective, randomised trial

Haemodynamic goal-directed therapies (GDT) may improve outcome following elective major surgery. So far, few data exist regarding haemodynamic optimization during emergency surgery. In this randomized, controlled trial, 50 surgical patients with hypovolemic or septic conditions were enrolled and we compared two algorithms of GDTs based either on conventional parameters and pressure pulse variation (control group) or on cardiac index, global end-diastolic volume index and stroke volume variation as derived from the PiCCO monitoring system (optimized group). Postoperative outcome was estimated by a composite index including major complications and by the Sequential Organ Failure Assessment (SOFA) Score within the first 3 days after surgery (POD1, POD2 and POD3). Data from 43 patients were analyzed (control group, N = 23; optimized group, N = 20). Similar amounts of fluid were given in the two groups. Intraoperatively, dobutamine was given in 45 % optimized patients but in no control patients. Major complications occurred more frequently in the optimized group [19 (95 %) versus 10 (40 %) in the control group, P < 0.001]. Likewise, SOFA scores were higher in the optimized group on POD1 (10.2 ± 2.5 versus 6.6 ± 2.2 in the control group, P = 0.001), POD2 (8.4 ± 2.6 vs 5.0 ± 2.4 in the control group, P = 0.002) and POD 3 (5.2 ± 3.6 and 2.2 ± 1.3 in the control group, P = 0.01). There was no significant difference in hospital mortality (13 % in the control group and 25 % in the optimized group). Haemodynamic optimization based on volumetric and flow PiCCO-derived parameters was associated with a less favorable postoperative outcome compared with a conventional GDT protocol during emergency surgery

Effect of Intraoperative High Positive End-Expiratory Pressure (PEEP) With Recruitment Maneuvers vs Low PEEP on Postoperative Pulmonary Complications in Obese Patients: A Randomized Clinical Trial (vol 321, pg 2292, 2019)

status: publishe

Effect of Intraoperative High Positive End-Expiratory Pressure (PEEP) With Recruitment Maneuvers vs Low PEEP on Postoperative Pulmonary Complications in Obese Patients: A Randomized Clinical Trial.

IMPORTANCE An intraoperative higher level of positive end-expiratory positive pressure (PEEP) with alveolar recruitment maneuvers improves respiratory function in obese patients undergoing surgery, but the effect on clinical outcomes is uncertain

Effect of intraoperative high Positive End-Expiratory Pressure (PEEP) with recruitment maneuvers vs low PEEP on postoperative pulmonary complications in obese patients : a randomized clinical trial

IMPORTANCE An intraoperative higher level of positive end-expiratory positive pressure (PEEP) with alveolar recruitment maneuvers improves respiratory function in obese patients undergoing surgery, but the effect on clinical outcomes is uncertain. OBJECTIVE To determine whether a higher level of PEEP with alveolar recruitment maneuvers decreases postoperative pulmonary complications in obese patients undergoing surgery compared with a lower level of PEEP. DESIGN, SETTING, AND PARTICIPANTS Randomized clinical trial of 2013 adults with body mass indices of 35 or greater and substantial risk for postoperative pulmonary complications who were undergoing noncardiac, nonneurological surgery under general anesthesia. The trial was conducted at 77 sites in 23 countries from July 2014-February 2018; final follow-up: May 2018. INTERVENTIONS Patients were randomized to the high level of PEEP group (n = 989), consisting of a PEEP level of 12 cm H2O with alveolar recruitment maneuvers (a stepwise increase of tidal volume and eventually PEEP) or to the low level of PEEP group (n = 987), consisting of a PEEP level of 4 cm H2O. All patients received volume-controlled ventilation with a tidal volume of 7 mL/kg of predicted body weight. MAIN OUTCOMES AND MEASURES The primary outcomewas a composite of pulmonary complications within the first 5 postoperative days, including respiratory failure, acute respiratory distress syndrome, bronchospasm, new pulmonary infiltrates, pulmonary infection, aspiration pneumonitis, pleural effusion, atelectasis, cardiopulmonary edema, and pneumothorax. Among the 9 prespecified secondary outcomes, 3 were intraoperative complications, including hypoxemia (oxygen desaturation with SpO(2) 1 minute). RESULTS Among 2013 adults who were randomized, 1976 (98.2%) completed the trial (mean age, 48.8 years; 1381 [69.9%] women; 1778 [90.1%] underwent abdominal operations). In the intention-to-treat analysis, the primary outcome occurred in 211 of 989 patients (21.3%) in the high level of PEEP group compared with 233 of 987 patients (23.6%) in the low level of PEEP group (difference, -2.3%[95% CI, -5.9% to 1.4%]; risk ratio, 0.93 [95% CI, 0.83 to 1.04]; P =.23). Among the 9 prespecified secondary outcomes, 6 were not significantly different between the high and low level of PEEP groups, and 3 were significantly different, including fewer patients with hypoxemia (5.0% in the high level of PEEP group vs 13.6% in the low level of PEEP group; difference, -8.6%[95% CI, -11.1% to 6.1%]; P <.001). CONCLUSIONS AND RELEVANCE Among obese patients undergoing surgery under general anesthesia, an intraoperative mechanical ventilation strategy with a higher level of PEEP and alveolar recruitment maneuvers, compared with a strategy with a lower level of PEEP, did not reduce postoperative pulmonary complications