The Covid-19 pandemic led to threatening shortages in healthcare of medical products such as face masks. Due to this major impact on our healthcare society an initiative was conducted between March and July 2020 for reprocessing of face masks from 19 different hospitals. This exceptional opportunity was used to study the costs impact and the carbon footprint of reprocessed face masks relative to new disposable face masks. The aim of this study is to conduct a Life Cycle Assessment (LCA) to assess and compare the climate change impact of disposed versus reprocessed face masks. In total 18.166 high quality medical FFP2 face masks were reprocessed through steam sterilization between March and July 2020. Greenhouse gas emissions during production, transport, sterilization and end-of-life processes were assessed. The background life cycle inventory data were retrieved from the ecoinvent database. The life cycle impact assessment method ReCiPe was used to translate emissions into climate change impact. The cost analysis is based on actual sterilization as well as associated costs compared to the prices of new disposable face masks. A Monte Carlo sampling was used to propagate the uncertainty of different inputs to the LCA results. The carbon footprint appears to be 58% lower for face masks which were reused for five times compared to new face masks which were used for one time only. The sensitivity analysis indicated that the loading capacity of the autoclave and rejection rate of face masks has a large influence on the carbon footprint. The estimated cost price of a reprocessed mask was €1.40 against €1.55. The Life Cycle Assessment demonstrates that reprocessed FFP2 face masks from a circular economy perspective have a lower climate change impact on the carbon footprint than new face masks. For policymakers it is important to realize that the carbon footprint of medical products such as face masks may be reduced by means of circular economy strategies. This study demonstrated a lower climate change impact and lower costs when reprocessing and reusing disposable face masks for five times. Therefore, this study may serve as an inspiration for investigating reprocessing of other medical products that may become scarce. Finally, this study advocates that circular design engineering principles should be taken into account when designing medical devices. This will lead to more sustainable products that have a lower carbon footprint and may be manufactured at lower costs.

NCT03071432.

Background: The baroreflex regulates arterial blood pressure (BP). During periods when blood pressure changes, cerebral blood flow (CBF) is kept constant by cerebral autoregulation (CA). In patients with diabetes mellitus (DM), low baroreflex sensitivity (BRS) is associated with impaired CA. As sevoflurane-based anaesthesia obliterates BRS, we hypothesised that this could aggravate the already impaired CA in patients with DM resulting in a 'double-hit' on cerebral perfusion leading to increased fluctuations in blood pressure and cerebral perfusion. Methods: On the day before surgery, we measured CBF velocity (CBFV), heart rate, and BP to determine BRS and CA efficacy (CBFV mean-to-BP mean-phase lead) in 25 patients with DM and in 14 controls. During the operation, BRS and CA efficacy were determined during sevoflurane-based anaesthesia. Patients with DM were divided into a group with high BRS (DM BRS[) and a group with low BRS (DM BRSY). Values presented are median (inter-quartile range). Results: Preoperative vs intraoperative BRS was 6.2 (4.5e8.5) vs 1.9 (1.1e2.5, P<0.001) ms mm Hg À1 for controls, 5.8 (4.9e7.6) vs 2.7 (1.5e3.9, P<0.001) ms mm Hg À1 for patients with DM BRS[ , and 1.9 (1.5e2.8) vs 1.1 (0.6e2.5, P¼0.31) ms mm Hg À1 for patients with DM BRSY. Preoperative vs intraoperative CA efficacy was 43 (38e46) vs 43 (38e51, P¼0.30), 44 (36e49) vs 41 (32e49, P¼0.52), and 34 (28e40) vs 30 (27e38, P¼0.64) for controls, DM BRS[ , and DM BRSY patients, respectively. Conclusions: In diabetic patients with low preoperative BRS, preoperative CA efficacy was also impaired. In controls and diabetic patients, CA was unaffected by sevoflurane-based anaesthesia. We therefore conclude that sevoflurane-based anaesthesia does not contribute to a 'double-hit' phenomenon on cerebral perfusion. Clinical trial registration: NCT 03071432.

BACKGROUND Classically, cerebral autoregulation (CA) entails cerebral blood flow (CBF) remaining constant by cerebrovascular tone adapting to fluctuations in mean arterial pressure (MAP) between ∼60 and ∼150 mmHg. However, this is not an on–off mechanism; previous work has suggested that vasomotor tone is proportionally related to CA function. During propofol-based anaesthesia, there is cerebrovascular vasoconstriction, and static CA remains intact. Sevoflurane-based anaesthesia induces cerebral vasodilation and attenuates CA dose-dependently. It is unclear how this translates to dynamic CA across a range of blood pressures in the autoregulatory range. OBJECTIVE The aim of this study was to quantify the effect of step-wise increases in MAP between 60 and 100 mmHg, using phenylephrine, on dynamic CA during propofol- and sevoflurane-based anaesthesia. DESIGN A nonrandomised interventional trial. SETTING Single centre enrolment started on 11 January 2019 and ended on 23 September 2019. PATIENTS We studied American Society of Anesthesiologists (ASA) I/II patients undergoing noncardiothoracic, nonneurosurgical and nonlaparoscopic surgery under general anaesthesia. INTERVENTION In this study, cerebrovascular tone was manipulated in the autoregulatory range by increasing MAP step-wise using phenylephrine in patients receiving either propofol- or sevoflurane-based anaesthesia. MAP and mean middle cerebral artery blood velocity (MCA V mean ) were measured in ASA I and II patients, anaesthetised with either propofol ( n = 26) or sevoflurane ( n = 28), during 10 mmHg step-wise increments of MAP between 60 and 100 mmHg. Static CA was determined by plotting 2-min averaged MCA V mean versus MAP. Dynamic CA was determined using transfer function analysis and expressed as the phase lead (°) between MAP and MCA V mean oscillations, created with positive pressure ventilation with a frequency of 6 min −1 . MAIN OUTCOMES The primary outcome of this study was the response of dynamic CA during step-wise increases in MAP during propofol- and sevoflurane-based anaesthesia. RESULTS MAP levels achieved per step-wise increments were comparable between anaesthesia regiment (63 ± 3, 72 ± 2, 80 ± 2, 90 ± 2, 100 ± 3 mmHg, and 61 ± 4, 71 ± 2, 80 ± 2, 89 ± 2, 98 ± 4 mmHg for propofol and sevoflurane, respectively). MCA V mean increased more during step-wise MAP increments for sevoflurane compared to propofol ( P ≤0.001). Dynamic CA improved during propofol (0.73° mmHg −1 , 95% CI 0.51 to 0.95; P ≤ 0.001)) and...