Most terrestrial animals demonstrate an autonomic reflex that facilitates survival during prolonged submersion under water. This diving response is characterized by bradycardia, apnea and selective increases in peripheral vascular resistance. Stimulation of the nose and nasal passages is thought to be primarily responsible for providing the sensory afferent signals initiating this protective reflex. Consequently, the primary objective of this research was to determine the central terminal projections of nerves innervating the external nose, nasal vestibule and nasal passages of rats. We injected wheat germ agglutinin (WGA) into specific external nasal locations, into the internal nasal passages of rats both with and without intact anterior ethmoidal nerves (AENs), and directly into trigeminal nerves innervating the nose and nasal region. The central terminations of these projections within the medulla were then precisely mapped. Results indicate that the internal nasal branch of the AEN and the nasopalatine nerve, but not the infraorbital nerve (ION), provide primary innervation of the internal nasal passages. The results also suggest afferent fibers from the internal nasal passages, but not external nasal region, project to the medullary dorsal horn (MDH) in an appropriate anatomical way to cause the activation of secondary neurons within the ventral MDH that express Fos protein during diving. We conclude that innervation of the anterior nasal passages by the AEN and nasopalatine nerve is likely to provide the afferent information responsible for the activation of secondary neurons within MDH during voluntary diving in rats.

Objective Dying in the intensive care unit (ICU) has changed over the last twenty years due to increased utilization of palliative care. We sought to examine how palliative medicine (PM) integration into critical care medicine has changed outcomes in end of life including the utilization of do not resuscitate (no cardiopulmonary resuscitation but continue treatment) and comfort care orders (No resuscitation, only comfort medication). Design: Retrospective observational review of critical care patients who died during admission between two decades, 2008 to 09 and 2018 to 19. Setting: Single urban tertiary care academic medical center in Washington, D.C. Patients: Adult patients who were treated in any ICU during the admission which they died. Interventions and Measurements We sought to measure PM involvement across the two decades and its association with end of life care including do not resuscitate (DNR) and comfort care (CC) orders. Main Results: 571 cases were analyzed. Mean age was 65 ± 15, 46% were female. In univariate analysis significantly more patients received PM in 2018 to 19 (40% vs. 27%, p = .002). DNR status increased significantly over time (74% to 84%, p = .002) and was significantly more common in patients who were receiving PM (96% vs. 72%, p < 0.001). CC also increased over time (56% to 70%, p = <0.001), and was more common in PM patients (87% vs. 53%, p < 0.001). Death in the ICU decreased significantly over time (94% to 86%, p = .002) and was significantly lower in PM patients (76% vs. 96%, p < 0.001). The adjusted odds of getting CC for those receiving versus those not receiving PM were 14.51 (5.49-38.36, p < 0.001) in 2008 to 09 versus 3.89 (2.27-6.68, p < 0.001) in 2018 to 19. Conclusion: PM involvement increased significantly across a decade in our ICU and was significantly associated with incidence of DNR and CC orders as well as the decreased incidence of dying in the ICU. The increase in DNR and CC orders independent of PM over the past decade reflect intensivists delivering PM services.

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