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To understand patterns in CO2 partial pressure (PCO2) over time in wetlands' surface water and porewater, we examined the relationship between PCO2 and land–atmosphere flux of CO2 at the ecosystem scale at 22 Northern Hemisphere wetland sites synthesized through an open call. Sites spanned 6 major wetland types (tidal, alpine, fen, bog, marsh, and prairie pothole/karst), 7 Köppen climates, and 16 different years. Ecosystem respiration (Reco) and gross primary production (GPP), components of vertical CO2 flux, were compared to PCO2, a component of lateral CO2 flux, to determine if photosynthetic rates and soil respiration consistently influence wetland surface and porewater CO2 concentrations across wetlands. Similar to drivers of primary productivity at the ecosystem scale, PCO2 was strongly positively correlated with air temperature (Tair) at most sites. Monthly average PCO2 tended to peak towards the middle of the year and was more strongly related to Reco than GPP. Our results suggest Reco may be related to biologically driven PCO2 in wetlands, but the relationship is site-specific and could be an artifact of differently timed seasonal cycles or other factors. Higher levels of discharge do not consistently alter the relationship between Reco and temperature normalized PCO2. This work synthesizes relevant data and identifies key knowledge gaps in drivers of wetland respiration. [ABSTRACT FROM AUTHOR]

Background Opioids, commonly used to control pain associated with surgery, are known to prolong the duration of mechanical ventilation and length of hospital stay. A wide range of adjunctive strategies are currently utilized to reduce postoperative pain, such as local and regional nerve blocks, nerve cryoablation, and adjunctive medications. We hypothesized that dronabinol (a synthetic cannabinoid) in conjunction with standard opioid pain management will reduce opioid requirements to manage postoperative pain. Methods Sixty-eight patients who underwent isolated first-time coronary artery bypass graft surgery were randomized to either the control group, who received only standard opioid-based analgesia, or the dronabinol group, who received dronabinol (a synthetic cannabinoid) in addition to standard opioid-based analgesia. Dronabinol was given in the preoperative unit, before extubation in the ICU, and after extubation on the first postoperative day. Preoperative, intraoperative, and postoperative parameters were compared under an IRB-approved protocol. The primary endpoints were the postoperative opioid requirement, duration of mechanical ventilation, and ICU length of stay, and the secondary endpoints were the duration of inotropic support needed, left ventricular ejection fraction (LVEF), and the change in LVEF. This study was undertaken at Northwest Medical Center, Tucson, AZ, USA. Results Sixty-eight patients were randomized to either the control group (n = 37) or the dronabinol group (n = 31). Groups were similar in terms of demographic features and comorbidities. The total postoperative opioid requirement was significantly lower in the dronabinol group [39.62 vs 23.68 morphine milligram equivalents (MMEs), p = 0.0037], representing a 40% reduction. Duration of mechanical ventilation (7.03 vs 6.03h, p = 0.5004), ICU length of stay (71.43 vs 63.77h, p = 0.4227), and inotropic support requirement (0.6757 vs 0.6129 days, p = 0.7333) were similar in the control and the dronabinol groups. However, there was a trend towards lower durations in each endpoint in the dronabinol group. Interestingly, a significantly better preoperative to postoperative LVEF change was observed in the dronabinol group (3.51% vs 6.45%, p = 0.0451). Conclusions Our study found a 40% reduction in opioid use and a significantly greater improvement in LVEF in patients treated with adjunctive dronabinol. Mechanical ventilation duration, ICU length of stay, and inotropic support requirement tended to be lower in the dronabinol group, though did not reach statistical significance. The results of this study, although limited by sample size, are very encouraging and validate our ongoing investigation., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2024, Kumar et al.)