Unexpected deposits in the anesthetic circuit: a possible cause of PEEP/Pmax valve malfunction.

PEEP is regulated by the internal PEEP/maximum peak inspiratory pressure limit (Pmax) valve. Malfunctioning of the PEEP/Pmax valve can result in the creation of unintentional or unstable PEEP, and a reduction of inspired tidal volume. Some of our Dräger Fabius® anesthesia machines were noted to exhibit changes in expiratory waveforms and unstable PEEP during general anesthesia. We considered that the cause was associated with PEEP/Pmax valve malfunction, and then investigated the problems in collaboration with the manufacturer. Seven of the 22 Dräger Fabius® anesthesia workstations at our department exhibited problems with their PEEP/Pmax valves. We replaced the PEEP membrane and sealing washers in these seven anesthesia machines, and the problems were temporarily resolved. After a short interval, however, one of the seven machines began to show a similar phenomenon. We then asked the manufacturer to overhaul the PEEP/Pmax valve and the entire breathing circuit of the machine. On close investigation, we found that the valve components and the internal surface of the breathing circuit were contaminated with unexpected deposits. The build-up of deposits occurred within a year after the previous regular inspection. Our troubleshooting process determined the issue with the PEEP/Pmax valve, which could go unnoticed because the valve is encased inside the breathing circuit, and requires disassembly for close inspection. Our findings should raise awareness regarding the importance of the preventive maintenance cycle as a safety precaution to keep the anesthetic circuit free of unexpected contamination.

[Preoperative Cardiovascular Evaluation and Management of Patients with Coronary Artery Disease].

With aging of population and increasing number of percutaneous coronary interventions, we frequently encounter patients with coronary artery disease (CAD) and coronary artery stents in the perioperative period. CAD increases the risk of perioperative myocardial infarction which worsens prognosis. It is important for us to evaluate those patients properly. In this review, we describe a classification and characteristics of perioperative myocardial infarction and highlight the mechanism and risk factors of stent thrombosis. We present a way of evaluation and perioperative management of patients with CAD, based on recent guidelines and findings. We present our real cases and perioperative management of CAD and coronary artery stents.

Allergic reactions to propofol in adult patients with egg or soybean allergy: a retrospective cohort study from a large database of a single institute.

BACKGROUND: In recent years, many reports have indicated that propofol is safe to administer to patients with egg/soybean allergy in Western countries. Egg allergy is more frequent in Asia, but there are limited reports regarding allergic reactions to propofol use among adults. This study aimed to determine whether propofol causes allergic reactions in patients with egg/soybean allergy. METHODS: Adult patients who underwent surgery involving anesthesiologists from 2018 to 2021 were included. In all patients, we reviewed food allergy information in their electronic medical record and extracted anesthetics. Patients with egg/soybean allergy were subdivided into two groups on the basis of intraoperative use of propofol. We evaluated each group for allergic reactions within 24 h after the induction of anesthesia. The primary outcome was a relative risk of allergic reactions after propofol use for patients with egg/soybean allergy. RESULTS: In total, 22,111 patients with 28,710 anesthesia records were identified. Among patients with egg/soybean allergy, 173 (0.8%) patients and 237 (0.8%) anesthesia records were included in the study. Among the records of egg-/soybean-allergic patients, 151 were administered propofol, and 86 were not. The relative risk of allergic reactions after propofol use for patients with egg/soybean allergy was 1.14 (95% confidence interval, 0.10-12.4; p = 0.74). CONCLUSION: The use of propofol in patients with egg/soybean allergy does not significantly increase the relative risk of allergic reactions. Therefore, anesthesiologists can appropriately determine the indication for propofol, even in patients with egg/soybean allergy. TRIAL REGISTRATION: UMIN-CTN, UMIN000049321 registered 26 October 2022 - retrospectively registered, https://center6.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000056167.

Sildenafil ameliorates right ventricular early molecular derangement during left ventricular pressure overload.

Right ventricular (RV) dysfunction following left ventricular (LV) failure is associated with poor prognosis. RV remodeling is thought initiated by the increase in the afterload of RV due to secondary pulmonary hypertension (PH) to impaired LV function; however, RV molecular changes might occur in earlier stages of the disease. cGMP (cyclic guanosine monophosphate)-phosphodiesterase 5 (PDE5) inhibitors, widely used to treat PH through their pulmonary vasorelaxation properties, have shown direct cardiac benefits, but their impacts on the RV in LV diseases are not fully determined. Here we show that RV molecular alterations occur early in the absence of RV hemodynamic changes during LV pressure-overload and are ameliorated by PDE5 inhibition. Two-day moderate LV pressure-overload (transverse aortic constriction) neither altered RV pressure/ function nor RV weight in mice, while it induced only mild LV hypertrophy. Importantly, pathological molecular features were already induced in the RV free wall myocardium, including up-regulation of gene markers for hypertrophy and inflammation, and activation of extracellular signal-regulated kinase (ERK) and calcineurin. Concomitant PDE5 inhibition (sildenafil) prevented induction of such pathological genes and activation of ERK and calcineurin in the RV as well as in the LV. Importantly, dexamethasone also prevented these RV molecular changes, similarly to sildenafil treatment. These results suggest the contributory role of inflammation to the early pathological interventricular interaction between RV and LV. The current study provides the first evidence for the novel early molecular cross-talk between RV and LV, preceding RV hemodynamic changes in LV disease, and supports the therapeutic strategy of enhancing cGMP signaling pathway to treat heart diseases.