Objective To explore the humidification effects between the humidifiers Venturi high-flow oxygen therapy(HVHF)and the high-flow humidified oxygen therapy in the treatment of patients with tracheotomy after the withdrawal of ventilator,and analyse the humidification performance and effect of airway humidification on the two oxygen therapies hence to provide an objective basis for selection of a humidified oxygen therapy.Methods A total of 146 ICU patients who had tracheotomy and completely withdrawal of ventilator in a general hospital in Shenzhen from July 2020 to December 2021 were randomly divided into trial group(n=73)and control group(n=73).With identical speed of airflow,patients in the trial groups were treated with HVHF and the patients of control group were offered with high-flow humidified oxygen therapy via AIRVOTM2.Data of the two groups were compared at the time points of days 0,2,7 and 14 in terms of absolute humidity(AH),relative humidity(RH),temperature(T)),sputum viscosity,arterial partial pressure of oxygen(PaO2),arterial partial pressure of carbon dioxide(PaCO2),oxygenation index(PaO2/FIO2)and the incidence of pulmonary infection.Results In the study,total of 61 patients in the control group and 72 patients in the trial group completed the high-flow humidified oxygen therapies,due to tubing detachments in 12 and 1 patients in the two groups,respectively.Repeated-Measures ANOVA analysis showed that,in both groups,there was a time effect(P<0.05)between the absolute humidity,relative humidity,temperature of the gas,PaO2,PaCO2,and PaO2/FiO2 at different time points.PaO2 and PaO2/FiO2 in both groups showed interactions at different time points(P<0.05).PaO2 and PaO2/FiO2 in the trial group were better than those in the control group at the time points of days 2,7 and 14(P<0.05).On days 2,7 and 14,the viscosity of sputum in the intervention group was better than that in the control group,and the incidence of pulmonary infection in the trial group was significantly lower than that in the control group(P<0.05).Conclusions HVHF and AIRVOTM2 both exhibit no obvious difference in gas humidification via high-flow humidification oxygen therapy in the patients with tracheotomy after withdrawal of ventilator.However,HVHF is superior to AIRVOTM2 in terms of improving airway humidification and oxygenation as well as reducing lung infection.Therefore,it is suggested that an HVHF is preferable for high-flow humidified oxygen therapy in treating the patients with tracheotomy after the withdrawal of ventilator.

The laterodorsal tegmentum (LDT) is a brain structure involved in distinct behaviors including arousal, reward, and innate fear. How environmental stimuli and top-down control from high-order sensory and limbic cortical areas converge and coordinate in this region to modulate diverse behavioral outputs remains unclear. Using a modified rabies virus, we applied monosynaptic retrograde tracing to the whole brain to examine the LDT cell type specific upstream nuclei. The LDT received very strong midbrain and hindbrain afferents and moderate cortical and hypothalamic innervation but weak connections to the thalamus. The main projection neurons from cortical areas were restricted to the limbic lobe, including the ventral orbital cortex (VO), prelimbic, and cingulate cortices. Although different cell populations received qualitatively similar inputs, primarily via afferents from the periaqueductal gray area, superior colliculus, and the LDT itself, parvalbumin-positive (PV) GABAergic cells received preferential projections from local LDT neurons. With regard to the different subtypes of GABAergic cells, a considerable number of nuclei, including those of the ventral tegmental area, central amygdaloid nucleus, and VO, made significantly greater inputs to somatostatin-positive cells than to PV cells. Diverse inputs to the LDT on a system-wide level were revealed.