Anesthesiology最新文献

Cataract surgeries are among the most common outpatient procedures in the United States, typically accomplished with topical anesthesia and light sedation. Evidence demonstrates no benefit for comprehensive preoperative medical evaluation before low-risk procedures. In 2019, the Centers for Medicare & Medicaid Services (Baltimore, Maryland) revised regulations for hospitals and ambulatory surgery centers, eliminating the previous requirement for a history and physical examination within 30 days of ambulatory surgeries, regardless of risk. Professional guidance from the Society for Ambulatory Anesthesia (Milwaukee, Wisconsin) and the American Academy of Ophthalmology (San Francisco, California) confirms that routine, comprehensive evaluation before cataract surgeries is nonbeneficial. Despite alignment of evidence, regulatory guidance, and expert consensus, implementation has been inconsistent. Unnecessary evaluations delay care and create barriers for patients with vision impairment. This article describes efforts to streamline preoperative evaluation for low-risk eye surgeries and underscores the ethical imperative of reducing low-value practices in perioperative medicine, particularly for vulnerable patient populations.

Background: GABAergic neurons in the preoptic area (POA) play a crucial role in sleep regulation, with distinct subpopulations promoting wakefulness and sleep. Dexmedetomidine has the unique property of inducing arousable sedation, but the underlying mechanisms remain incompletely understood. In this study, we propose that POA-derived GABAergic neurons regulate natural sleep and wakefulness states through different projections and act similarly for dexmedetomidine-induced sedation and arousability.

Methods: In this study, 99 male and 56 female GAD2-cre mice and 10 male C57BL/6J mice (N = 165) were used. The power density in the EEG/EMG bands was used to assess the depth of dexmedetomidine-induced sedation and to determine the sleep-wakefulness states. A fiber photometry/patch clamp was used to detect changes in the excitability of GABAergic neurons projecting from the POA to the ventral tegmental area (GABAPOA-VTA neurons) and to the lateral hypothalamus (GABAPOA-LH neurons). Chemogenetics was used to modulate the excitability of the GABAPOA-VTA and GABAPOA-LH neurons. Viral tracing was used to map the functional connectivity between POA-derived GABAergic neurons and their targets in the VTA and LH.

Results: According to the EEG, EMG, and fiber photometry recordings, GABAPOA-VTA neurons showed elevated activity during natural wakefulness or 40 μg/kg dexmedetomidine-induced sedation. Chemogenetic activation of GABAPOA-VTA neurons increased natural wakefulness and reduced dexmedetomidine-induced sedation. The GABAPOA-VTA and GABAPOA-LH neurons played opposing roles in natural sleep and dexmedetomidine-induced sedation. Retrograde tracing revealed a minimal overlap between these two neuronal subpopulations. Orthodromic tracing demonstrated that GABAPOA-VTA neurons preferentially innervated VTA-derived GABAergic neurons, whereas GABAPOA-LH neurons mainly projected to LH orexin neurons.

Conclusions: In addition to mediating the sedative versus arousal effects of dexmedetomidine, two distinct subpopulations of GABAergic neurons in the POA are also responsible for promoting natural sleep and wakefulness, respectively.