This study investigated the accuracy, drift, and clinical usefulness of a new optical transcutaneous oxygen tension (tcPO 2) measuring technique, combined with a conventional electrochemical transcutaneous carbon dioxide (tcPCO 2) measurement and reflectance pulse oximetry in the novel transcutaneous OxiVenT™ Sensor. In vitro gas studies were performed to measure accuracy and drift of tcPO 2 and tcPCO 2. Clinical usefulness for tcPO 2 and tcPCO 2 monitoring was assessed in neonates. In healthy adult volunteers, measured oxygen saturation values (SpO 2) were compared with arterially sampled oxygen saturation values (SaO 2) during controlled hypoxemia. In vitro correlation and agreement with gas mixtures of tcPO 2 (r = 0.999, bias 3.0 mm Hg, limits of agreement − 6.6 to 4.9 mm Hg) and tcPCO 2 (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 tcPO 2 (0.30 (0.63 SD) mm Hg/24 h) and highly acceptable for tcPCO 2 (− 2.53 (1.04 SD) mm Hg/12 h). Clinical use in neonates showed good usability and feasibility. SpO 2-SaO 2 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 tcPO 2 , tcPCO 2 , and SpO 2 sensor with a new oxygen fluorescence quenching technique is clinically usable and provides good overall accuracy and negligible tcPO 2 drift. Accurate and low-drift tcPO 2 monitoring offers improved measurement validity for long-term monitoring of blood and tissue oxygenation. Keywords Transcutaneous. tcPO 2. tcPCO 2. Oxygen. Fluorescence quenching * Willem van Weteringen
Conclusion: Real-time and non-invasive effect monitoring of drug therapy combined with model-based exposure provides relevant information to clinicians and can importantly improve therapy. The variability between and within patients emphasizes the importance of individual, objective evaluation of pharmacotherapy. These measurements, together with data on ADRs, allow for precision medicine in neonatology that should be brought to the bedside.
<b><i>Introduction:</i></b> Evaluation of pharmacotherapy during intensive care treatment is commonly based on subjective, intermittent interpretations of physiological parameters. Real-time visualization and analysis may improve drug effect evaluation. We aimed to evaluate the effects of the respiratory stimulant doxapram objectively in preterm infants using continuous physiological parameters. <b><i>Methods:</i></b> In this longitudinal observational study, preterm infants who received doxapram therapy were eligible for inclusion. Physiological data (1 Hz) were used to assess respiration and to evaluate therapy effects. The oxygen saturation (SpO<sub>2</sub>)/fraction of inspired oxygen (FiO<sub>2</sub>) ratio and the area under the 89% SpO<sub>2</sub> curve (duration × saturation depth below target) were calculated as measures of hypoxemia. Regression analyses were performed in 1-h timeframes to discriminate therapy failure (intubation or death) from success (no intubation). <b><i>Results:</i></b> Monitor data of 61 patients with a median postmenstrual age (PMA) at doxapram initiation of 28.7 (IQR 27.6–30.0) weeks were available. The success rate of doxapram therapy was 56%. Doxapram pharmacodynamics were reflected in an increased SpO<sub>2</sub> and SpO<sub>2</sub>/FiO<sub>2</sub> ratio as well as a decrease in episodes with saturations below target (SpO<sub>2</sub> <89%). The SpO<sub>2</sub>/FiO<sub>2</sub> ratio, corrected for PMA and mechanical ventilation before therapy start, discriminated best between therapy failure and success (highest AUC ROC of 0.83). <b><i>Conclusion:</i></b> The use of continuous physiological monitor data enables objective and detailed interpretation of doxapram in preterm infants. The SpO<sub>2</sub>/FiO<sub>2</sub> ratio is the best predictive parameter for therapy failure or success. Further implementation of real-time data analysis and treatment algorithms would provide new opportunities to treat newborns.
Background During laparoscopy, the abdominal cavity is insufflated with carbon dioxide (CO2) that could become contaminated with viruses and surgical smoke. Medical staff is potentially exposed when this gas leaks into the operating room through the instruments and past trocar valves. No detailed studies currently exist that have quantified these leakage pathways. Therefore, the goal of this study was to quantify the gas leakages through trocars and instruments, during minimally invasive procedures. Methods A model of the surgical environment was created, consisting of a rigid container with an interface for airtight clamping of laparoscopic equipment such as trocars and surgical instruments. The model was insufflated to 15 mm Hg using a pressure generator and a pneumotachograph measured the equipment gas leak. A protocol of several use cases was designed to simulate the motions and forces the surgeon exerts on the trocar during surgery. Results Twenty-three individual trocars and twenty-six laparoscopic instruments were measured for leakage under the different conditions of the protocol. Trocar leakages varied between 0 L/min and more than 30 L/min, the instruments revealed a range of leakages between 0 L/min and 5.5 L/min. The results showed that leakage performance varied widely between trocars and instruments and that the performance and location of the valves influenced trocar leakage. Conclusions We propose trocar redesigns to overcome specific causes of gas leaks. Moreover, an international testing standard for CO2 leakage for all new trocars and instruments is needed so surgical teams can avoid this potential health hazard when selecting new equipment.
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