Introduction: Rhabdomyolysis is characterized by destruction of muscle fibers by various causes and is diagnosed by increased creatine kinase concentrations in the blood. Myoglobin released into the blood may cause acute kidney injury. In this randomized controlled study, we hypothesized that myoglobin elimination would be faster when a hemoadsorber was added to a continuous veno-venous hemodialysis (CVVHD). Methods: Four patients in the control group received CVVHD with a high cut-off hemofilter using high blood and dialysate flows for 48 h. Four patients in the CytoSorb group received the same treatment, but in addition, the hemoadsorber CytoSorb® was inserted in front of the hemofilter and replaced once after 24 h. Blood samples were drawn simultaneously before (pre) and after (post) the hemofilter or else the hemoadsorber, after 5 and 30 min, as well as after 2, 4, 8, and 24 h. All measurements were repeated the next day after the hemoadsorber had been renewed in the CytoSorb group. Primary outcome was the area under the curve (AUC) of the relative myoglobin concentrations as percent of baseline. To evaluate the efficacy of myoglobin removal, relative reductions in myoglobin concentrations during one passage through each device at each time point were calculated. Results: Patients in the CytoSorb group had a significantly lower AUC during the first 24 h (42 ± 10% vs. 63 ± 6%, p = 0.029) as well as during the observation period of 48 h (26 ± 7% vs. 51 ± 12%, p = 0.029). The relative reductions for myoglobin were considerably higher in the CytoSorb group compared to the control group during the first 8 h. Conclusion: Myoglobin concentrations declined considerably faster when CytoSorb was added to a CVVHD. When compared to a high-cut-off hemofilter, efficacy of CytoSorb in myoglobin elimination was much better. Because of saturation after 8–12 h an exchange may be necessary.

Systemic inflammation alters the composition of exhaled breath, possibly helping clinicians diagnose conditions such as sepsis. We therefore evaluated changes in exhaled breath of rats given tumor necrosis factor-alpha (TNF-α). Thirty male Sprague-Dawley rats were randomly assigned to three groups (n = 10 each) with intravenous injections of normal saline (control), 200 µg·kg⁻¹ bodyweight TNF-α (TNF-α-200), or 600 µg·kg⁻¹ bodyweight TNF-α (TNF-α-600), and were observed for 24 h or until death. Animals were ventilated with highly-purified synthetic air to analyze exhaled air by multicapillary column–ion mobility spectrometry. Volatile organic compounds (VOCs) were identified from a database. We recorded blood pressure and cardiac output, along with cytokine plasma concentrations. Control rats survived the 24 h observation period, whereas mean survival time decreased to 22 h for TNF-α-200 and 23 h for TNF-α-600 rats. Mean arterial pressure decreased in TNF-α groups, whereas IL-6 increased, consistent with mild to moderate inflammation. Hundreds of VOCs were detected in exhalome. P-cymol increased by a factor-of-two 4 h after injection of TNF-α-600 compared to the control and TNF-α-200. We found that 1-butanol and 1-pentanol increased in both TNF-α groups after 20 h compared to the control. As breath analysis distinguishes between two doses of TNF-α and none, we conclude that it might help clinicians identify systemic inflammation.

Low-dose isoflurane stimulates spontaneous breathing. We, therefore, tested the hypothesis that isoflurane compared to propofol sedation for at least 48 h is associated with increased respiratory drive in intensive care patients after sedation stop. All patients in our intensive care unit receiving at least 48 h of isoflurane or propofol sedation in 2019 were included. The primary outcome was increased respiratory drive over 72 h after sedation stop, defined as an arterial carbon dioxide pressure below 35 mmHg and a base excess more than −2 mmol/L. Secondary outcomes were acid–base balance and ventilatory parameters. We analyzed 64 patients, 23 patients sedated with isoflurane and 41 patients sedated with propofol. Patients sedated with isoflurane were about three times as likely to show increased respiratory drive after sedation stop than those sedated with propofol: adjusted risk ratio [95% confidence interval]: 2.9 [1.3, 6.5], p = 0.010. After sedation stop, tidal volumes were significantly greater and arterial carbon dioxide partial pressures were significantly lower, while respiratory rates did not differ in isoflurane versus propofol-sedated patients. In conclusion, prolonged isoflurane use in intensive care patients is associated with increased respiratory drive after sedation stop. Beneficial effects of isoflurane sedation on respiratory drive may, thus, extend beyond the actual period of sedation.

The Mirus™ system (Technologie Institut Medizin GmbH, Germany) enables target-controlled delivery of volatile anaesthetics with open system ventilators. Its interface, positioned between Y-piece and the patient, injects anaesthetic vapor during inspiration, while adsorbing anaesthetic and resupplying it during the next inspiration. A newly introduced interface (Lisa-44) was evaluated under body temperature pressure saturated and normocapnic conditions using a test lung. Volume-controlled ventilation was applied with a 500 mL tidal volume, 10 bpm respiratory rate, and inspiratory flow (IF) times of 2.5 s and 0.5 s. Isoflurane (sevoflurane) target concentrations were stepwise increased to 1.5 MAC and then decreased. An external gas monitor recorded real-time anaesthetic concentrations. End-tidal concentrations (EC) and area under the curve (AUC) were analyzed for each breath. Accuracy and precision were assessed using Bland-Altman plots. Consumption was calculated and compared to historical controls. Mirus EC measurements correlated well with external gas monitor readings. ECs fluctuated around targets, with higher targets requiring more frequent injections and larger AUCs. Anaesthetic consumption was lower than historical controls and comparable to the Sedaconda ACD. At 0.3–0.5 MAC, hourly isoflurane consumption ranged from 1.0 to 1.7 mL (sevoflurane: 3.8–6.1 mL). However, very short IF times significantly increased consumption, reaching 43 mL sevoflurane at an EC of 2.6 vol%, with prolonged injections extending into the expiration phase. The new system demonstrates high accuracy, precision, and improved efficiency, suggesting reduced anaesthetic consumption in clinical use. However, high concentrations combined with very short IF times substantially increase consumption, indicating potential limitations.

Background: Volatile anesthetics are widely used for sedation in intensive care. Being potent greenhouse gases, their efficient utilization is imperative. We investigated whether the efficiency of anesthetic reflection devices, such as Sedaconda ACD-S (ACD), can be improved by thermocycling, i.e., cooling the reflector during expiration and warming it during inspiration, and aimed to identify the optimal temperatures required. Methods: A test lung connected to the ACD was ventilated under body temperature pressure saturated and normocapnic conditions. Isoflurane and sevoflurane were infused at rates of 0.5, 1, 2, and 5 mL/h, with sevoflurane additionally administered at 10 mL/h. For thermocycling, inspired air was heated to 37 °C by an active humidifier without water. Cooling in steps of 26, 21, 16, 11, 6, and 1 °C was achieved by passing air from the test lung through a freezer before reaching the ACD. Results: Thermocycling significantly increased concentrations of isoflurane and sevoflurane in the test lung compared with control conditions. Cooling of the expired air led to substantial increases down to a cooling temperature of 16 °C; below 16 °C, further increases in concentrations were much smaller. Interpolation of our data shows that at clinically used concentrations (isoflurane: 0.4–0.6 Vol%; sevoflurane: 0.9–1.1 Vol%), consumption could be reduced by 70% (isoflurane from 2.46 to 0.74 mL/h) and 72% (sevoflurane from 5.73 to 1.60 mL/h). Reflection efficiencies—the ratio of re-inspired from exhaled anesthetic molecules in one breath—increased from around 70% to 90%. Conclusions: Thermocycling significantly enhances the efficiency of volatile anesthetic reflection, offering a promising strategy to reduce the impact of intensive care sedation on climate change.