Citations

Abstract Introduction Sedation is routinely administered to facilitate comfort and tolerance of life support for critically ill adults dependent on invasive mechanical ventilation. Isoflurane, a widely used anesthetic during surgery, has properties that may also benefit ICU patients requiring continuous sedation. However, efficacy as a sedative and safety in this population is not well established. Methods We conducted two identically designed multicenter randomized trials, INSPIRE ICU1 and INSPIRE ICU2, at hospitals across the US. Ventilator-dependent adults were randomly assigned in a 1.5:1 ratio to receive either inhaled isoflurane or intravenous propofol as the first-line sedative for up to 48 ± 6 hours, targeting a sedation depth between Richmond agitation-sedation scale (RASS) -1 (drowsy) to -4 (responsive only to physical stimuli). Isoflurane was administered via an anesthetic conserving device (Sedaconda ACD-S). In both arms, opioids were permitted at the lowest dose required to achieve freedom from pain. The primary outcome was the percentage of time at target sedation level, assessed as a noninferiority outcome with pre-specified margin of 15%. Secondary outcomes included opioid exposure, wake-up time after end of treatment, time to extubation, and proportion of time with spontaneous breathing effort. Results A total of 470 combined participants were included in the two trials. In each trial, 142 patients were randomly assigned to isoflurane and 93 to propofol. In INSPIRE ICU1, percentage of time within target sedation depth was 77.1 [53.2, 89.9] % with isoflurane and 80.9 [58.2, 96.4] % with propofol (difference -1.5 [-8.9, >99] %; p < 0.01 for noninferiority). In INSPIRE ICU2, percentage of time within target sedation depth was 72.6 [66.4, 78.9] % with isoflurane and 74.5 [67.5, 81.5] % with propofol (difference -1.9 [-9.4, >99] %; p < 0.01 for noninferiority). In both trials, patients assigned to isoflurane received significantly less opioid, measured as fentanyl equivalents, during the treatment period. In INSPIRE ICU2, participants receiving isoflurane were significantly likelier to exhibit spontaneous breathing efforts, but this finding was not replicated in INSPIRE ICU1. There were no significant differences in time to wake-up or time to extubation between groups in either trial. No episodes of malignant hyperthermia or propofol infusion syndrome were reported. Adverse events were comparable in type and frequency between groups. Conclusions In two US multicenter trials, isoflurane was noninferior to propofol for maintaining target sedation depth in adults undergoing invasive ventilation, and was associated with significantly lower opioid exposure. (NCT05327296, NCT05312385) This abstract is funded by: Sedana Medical

The retromer complex, composed of sorting nexin subunits and a Vps26/Vps29/Vps35 trimer, mediates sorting of retrograde cargo from the endosome to the trans-Golgi network. The retromer trimer subcomplex is an effector of Rab7 (Ypt7 in yeast). Whereas endosome targeting of human retromer has been shown to require Rab7-GTP, targeting of yeast retromer to the endosome is independent of Ypt7-GTP and requires the Vps5 and Vps17 retromer sorting nexin subunits. An evolutionarily conserved amino acid segment within Vps35 is required for Ypt7/Rab7 recognition in vivo by both yeast and human retromer, establishing that Rab recognition is a conserved feature of this subunit. Recognition of Ypt7 by retromer is required for its function in retrograde sorting, and in yeast cells lacking the guanine nucleotide exchange factor for Ypt7, retrograde cargo accumulates in endosomes that are decorated with retromer, revealing an additional role for Rab recognition at the cargo export stage of the retromer functional cycle. In addition, yeast retromer trimer antagonizes Ypt7-regulated organelle tethering and fusion of endosomes/vacuoles via recognition of Ypt7. Thus retromer has dual roles in retrograde cargo export and in controlling the fusion dynamics of the late endovacuolar system.