Predicting a low cortisol response to adrenocorticotrophic hormone in the critically ill: a retrospective cohort study

Introduction: Identification of risk factors for diminished cortisol response to adrenocorticotrophic hormone (ACTH) in the critically ill could facilitate recognition of relative adrenal insufficiency in these patients. Therefore, we studied predictors of a low cortisol response to ACTH. Methods: A retrospective cohort study was conducted in a general intensive care unit of a university hospital over a three year period. The study included 405 critically ill patients, who underwent a 250 μg ACTH stimulation test because of prolonged hypotension or need for vasopressor/inotropic therapy. Plasma cortisol was measured before and 30 and 60 min after ACTH injection. A low adrenal response was defined as an increase in cortisol of less than 250 nmol/l or a peak cortisol level below 500 nmol/l. Various clinical variables were collected at admission and on the test day. Results: A low ACTH response occurred in 63% of patients. Predictors, in multivariate analysis, included sepsis at admission, low platelets, low pH and bicarbonate, low albumin levels, high Sequential Organ Failure Assessment score and absence of prior cardiac surgery, and these predictors were independent of baseline cortisol and intubation with etomidate. Baseline cortisol/albumin ratios, as an index of free cortisol, were directly related and increases in cortisol/albumin were inversely related to disease severity indicators such as the Simplified Acute Physiology Score II and Sequential Organ Failure Assessment score (Spearman r = -0.21; P < 0.0001). Conclusion: In critically ill patients, low pH/bicarbonate and platelet count, greater severity of disease and organ failure are predictors of a low adrenocortical response to ACTH, independent of baseline cortisol values and cortisol binding capacity in blood. These findings may help to delineate relative adrenal insufficiency and suggest that adrenocortical suppression occurs as a result of metabolic acidosis and coagulation disturbances

Effect of Bronchoscopy on Gas Exchange and Respiratory Mechanics in Critically Ill Patients With Atelectasis: An Observational Cohort Study

Background: Atelectasis frequently develops in critically ill patients and may result in impaired gas exchange among other complications. The long-term effects of bronchoscopy on gas exchange and the effects on respiratory mechanics are largely unknown.Objective: To evaluate the effect of bronchoscopy on gas exchange and respiratory mechanics in intensive care unit (ICU) patients with atelectasis.Methods: A retrospective, single-center cohort study of patients with clinical indication for bronchoscopy because of atelectasis diagnosed on chest X-ray (CXR).Results: In total, 101 bronchoscopies were performed in 88 ICU patients. Bronchoscopy improved oxygenation (defined as an increase of PaO2/FiO2 ratio &gt; 20 mmHg) and ventilation (defined as a decrease of &gt; 2 mmHg in partial pressure of CO2 in arterial blood) in 76 and 59% of procedures, respectively, for at least 24 h. Patients with a low baseline value of PaO2/FiO2 ratio and a high baseline value of PaCO2 were most likely to benefit from bronchoscopy. In addition, in intubated and pressure control ventilated patients, respiratory mechanics improved after bronchoscopy for up to 24 h. Mild complications, and in particular desaturation between 80 and 90%, were reported in 13% of the patients.Conclusions: In selected critically ill patients with atelectasis, bronchoscopy improves oxygenation, ventilation, and respiratory mechanics for at least 24 h

Quality improvement of Dutch ICUs from 2009 to 2021: A registry based observational study

Purpose: To investigate the development in quality of ICU care over time using the Dutch National Intensive Care Evaluation (NICE) registry. Materials and methods: We included data from all ICU admissions in the Netherlands from those ICUs that submitted complete data between 2009 and 2021 to the NICE registry. We determined median and interquartile range for eight quality indicators. To evaluate changes over time on the indicators, we performed multilevel regression analyses, once without and once with the COVID-19 years 2020 and 2021 included. Additionally we explored between-ICU heterogeneity by calculating intraclass correlation coefficients (ICC). Results: 705,822 ICU admissions from 55 (65%) ICUs were included in the analyses. ICU length of stay (LOS), duration of mechanical ventilation (MV), readmissions, in-hospital mortality, hypoglycemia, and pressure ulcers decreased significantly between 2009 and 2019 (OR <1). After including the COVID-19 pandemic years, the significant change in MV duration, ICU LOS, and pressure ulcers disappeared. We found an ICC ≤0.07 on the quality indicators for all years, except for pressure ulcers with an ICC of 0.27 for 2009 to 2021. Conclusions: Quality of Dutch ICU care based on seven indicators significantly improved from 2009 to 2019 and between-ICU heterogeneity is medium to small, except for pressure ulcers. The COVID-19 pandemic disturbed the trend in quality improvement, but unaltered the between-ICU heterogeneity

A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

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Comparison of outcome and characteristics between 6343 COVID-19 patients and 2256 other community-acquired viral pneumonia patients admitted to Dutch ICUs

Purpose: Describe the differences in characteristics and outcomes between COVID-19 and other viral pneumonia patients admitted to Dutch ICUs. Materials and methods: Data from the National-Intensive-Care-Evaluation-registry of COVID-19 patients admitted between February 15th and January 1th 2021 and other viral pneumonia patients admitted between January 1st 2017 and January 1st 2020 were used. Patients' characteristics, the unadjusted, and adjusted in-hospital mortality were compared. Results: 6343 COVID-19 and 2256 other viral pneumonia patients from 79 ICUs were included. The COVID-19 patients included more male (71.3 vs 49.8%), had a higher Body-Mass-Index (28.1 vs 25.5), less comorbidities (42.2 vs 72.7%), and a prolonged hospital length of stay (19 vs 9 days). The COVID-19 patients had a significantly higher crude in-hospital mortality rate (Odds ratio (OR) = 1.80), after adjustment for patient characteristics and ICU occupancy rate the OR was respectively 3.62 and 3.58. Conclusion: Higher mortality among COVID-19 patients could not be explained by patient characteristics and higher ICU occupancy rates, indicating that COVID-19 is more severe compared to other viral pneumonia. Our findings confirm earlier warnings of a high need of ICU capacity and high mortality rates among relatively healthy COVID-19 patients as this may lead to a higher mental workload for the staff. (c) 2021 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/)

Solar Powered Drones: Power Electronics

Sustainable energy technologies are ever-increasing in popularity, not only among companies but also among consumers. Photovoltaic, or PV, cells are amongst the most well known in this field. This project was set up for designing a PV-powered UAV that is able to generate an albedo map of an area equal or bigger than the campus of the TU Delft in a single run. PV cells, however, are highly susceptible to changes in weather conditions and have a range of voltages at which these cells can supply power. Besides that, unnecessary losses occur if the so-called ’Maximum Power Point’ (MPP) is not tracked. In this thesis, a boost converter is proposed for the aforementioned system to implement the maximum power point tracking and supply the, by the PV system produced, power as efficiently as possible to the UAV power system

Short-term patterns of pulsatile luteinizing hormone secretion do not differ between male-to-female transsexuals and heterosexual men

This study tested whether there is a difference in the pulsatile LH secretion between male-to-female transsexuals and eugonadal heterosexual men. The mean serum LH concentrations, the LH pulse frequency, and the LH pulse amplitude were compared between a group of eight male-to-female transsexuals and a group of 22 heterosexual men. Blood samples for LH determinations were collected every 10 min for seven hours. 17-β-estradiol and testosterone were measured at the beginning of each test. There were no significant differences between the heterosexual and transsexual group in LH pulse frequency (3.9±1.3 vs. 3.9±1.7), LH pulse amplitude (3.7±1.3 U/l vs. 3.0±0.5 U/l), mean serum LH concentration (5.2±1.4 U/l vs. 5.4±1.1 U/l), 17-β-estradiol (0.07±0.01 nmol/l vs. 0.08±0.02 nmol/l), or testosterone (22.9±3.7 nmol/l vs. 21.8±8.0 nmol/l). We conclude that the pulsatile release characteristics of LH do not allow a distinction between eugonadal heterosexual men and eugonadal male-to-female transsexuals