High estradiol and low testosterone levels are associated with critical illness in male but not in female COVID-19 patients: a retrospective cohort study., Emerging Microbes & Infections,

Routine use of cardiac output (CO) monitoring became available with the introduction of the pulmonary artery catheter into clinical practice. Since then, several systems have been developed that allow for a less-invasive CO monitoring. The so-called “non-calibrated pulse contour systems” (PCS) estimate CO based on pulse contour analysis of the arterial waveform, as determined by means of an arterial catheter without additional calibration. The transformation of the arterial waveform signal as a pressure measurement to a CO as a volume per time parameter requires a concise knowledge of the dynamic characteristics of the arterial vasculature. These characteristics cannot be measured non-invasively and must be estimated. Of the four commercially available systems, three use internal databases or nomograms based on patients’ demographic parameters and one uses a complex calculation to derive the necessary parameters from small oscillations of the arterial waveform that change with altered arterial dynamic characteristics. The operator must ensure that the arterial waveform is neither over- nor under-dampened. A fast-flush test of the catheter–transducer system allows for the evaluation of the dynamic response characteristics of the system and its dampening characteristics. Limitations to PCS must be acknowledged, i.e., in intra-aortic balloon-pump therapy or in states of low- or high-systemic vascular resistance where the accuracy is limited. Nevertheless, it has been shown that a perioperative algorithm-based use of PCS may reduce complications. When considering the method of operation and the limitations, the PCS are a helpful component in the armamentarium of the critical care physician.

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BackgroundPercutaneous dilatational tracheostomy (PDT) in critically ill patients often involves bronchoscopic optical guidance. However, this procedure is not without disadvantages. Therefore, we aimed to study a recently introduced endotracheal tube-mounted camera (VivaSightTM-SL tube [VST]; ETView, Misgav, Israel) for guiding PDT.MethodsThis was a randomized controlled trial involving 46 critically ill patients who received PDT using optical guidance with a VST or with bronchoscopy. The primary outcome measure was visualization of the tracheal structures (i.e., identification and monitoring of the thyroid, cricoid, and tracheal cartilage and the posterior wall) rated on 4-point Likert scales. Secondary measures were the quality of ventilation (before puncture and during the tracheostomy procedure rated on 4-point Likert scales) and blood gases sampled at standardized time points.ResultsThe mean ratings for visualization (lower values better; values given for per-protocol analysis) were 5.4 (95% CI 4.5–6.3) for the VST group and 4.0 (95% CI 4.0–4.0) for the bronchoscopy group (p < 0.001). Mean ventilation ratings were 2.5 (95% CI 2.1–2.9) for VST and 5.0 (95% CI 4.4–5.7) for bronchoscopy (p < 0.001). Arterial carbon dioxide increased to 5.9 (95% CI 5.4–6.5) kPa in the VST group vs. 8.3 (95% CI 7.2–9.5) kPa in the bronchoscopy group (p < 0.001), and pH decreased to 7.40 (95% CI 7.36–7.43) in the VST group vs. 7.26 (95% CI 7.22–7.30) in the bronchoscopy group (p < 0.001), at the end of the intervention.ConclusionsVisualization of PDT with the VST is not noninferior to guidance by bronchoscopy. Ventilation is superior with less hypercarbia with the VST. Because visualization is not a prerequisite for PDT, patients requiring stable ventilation with normocarbia may benefit from PDT with the VST.Trial registrationClinicalTrials.gov, NCT02861001. Registered on 13 June 2016.Electronic supplementary materialThe online version of this article (doi:10.1186/s13054-017-1901-0) contains supplementary material, which is available to authorized users.