Reconciling biodiversity with timber production and revenue via an intensive forest management experiment.

Understanding how land-management intensification shapes the relationships between biodiversity, yield, and economic benefit is critical for managing natural resources. Yet, manipulative experiments that test how herbicides affect these relationships are scarce, particularly in forest ecosystems where considerable time lags exist between harvest revenue and initial investments. We assessed these relationships by combining 7 yr of biodiversity surveys (>800 taxa) and forecasts of timber yield and economic return from a replicated, large-scale experiment that manipulated herbicide application intensity in operational timber plantations. Herbicides reduced species richness across trophic groups (-18%), but responses by higher-level trophic groups were more variable (0-38% reduction) than plant responses (-40%). Financial discounting, a conventional economic method to standardize past and future cash flows, strongly modified biodiversity-revenue relationships caused by management intensity. Despite a projected 28% timber yield gain with herbicides, biodiversity-revenue trade-offs were muted when opportunity costs were high (i.e., economic discount rates ≥7%). Although herbicides can drive biodiversity-yield trade-offs, under certain conditions, financial discounting provides opportunities to reconcile biodiversity conservation with revenue.

Association of earlier extubation and postoperative delirium after coronary artery bypass grafting.

OBJECTIVES: Earlier extubation after cardiac surgery is reported to have benefits on length of stay and complication rates, but the influence on postoperative delirium remains unclear. We sought to determine the effect of earlier extubation on delirium after coronary artery bypass grafting. METHODS: A single-center retrospective review of consecutive isolated coronary artery bypass grafting patients from January 1, 2010, to December 31, 2015, was conducted. Baseline demographic characteristics, preoperative comorbidities, intraoperative data, and postoperative data were collected. A multivariable logistic regression was performed with analysis limited to extubation within the first 24 hours postoperatively. RESULTS: We identified 2561 eligible patients. Delirium occurred in 13.9% (n = 357). Duration of postoperative mechanical ventilation was associated with higher delirium rates following adjustment, particularly after 12 to 24 hours (hourly odds ratio, 1.12; 95% confidence interval, 1.05-1.19; P < .001). No association was observed during the time period from 0 to 12 hours (hourly odds ratio, 1.02; 95% confidence interval, 0.99-1.06; P = .218). Major adverse events were associated with duration of ventilation after 0 to 12 hours (hourly odds ratio, 1.08; 95% confidence interval, 1.03-1.14; P < .002) but not after 12 to 24 hours (hourly odds ratio, 1.04; 95% CI, 0.96-1.14; P = .316). The overall rate of reintubation was 2.9% (n = 73). CONCLUSIONS: Our findings suggest that delirium rates increase with lengthier postoperative ventilation times. This study provides the basis for consideration of the appropriate selection of earlier extubation to minimize delirium in patients undergoing cardiac surgery.

Hemodynamic effects of low-dose bupivacaine spinal anesthesia for cesarean section: A randomized controlled trial.

BACKGROUND: Spinal anesthesia is the most common technique for cesarean section. The conventional local anesthetic dose has been decreasing over time to 8-12.5 mg of bupivacaine. Lower doses of bupivacaine may be associated with reduced incidence of hypotension and other complications. This low dose also may be associated with improved maternal cardiac index (CI). We hypothesized that low dose spinal anesthesia using 4.5 mg bupivacaine would result in improved maternal CI when compared with conventional dose (9 mg) intrathecal bupivacaine. METHODS: This randomized controlled trial included all healthy parturients presenting for elective cesarean section. In addition to standard monitors, an arterial line was placed for pulse contour cardiac output measurement. Due to limited data on maternal cardiac output during cesarean section, we had to power our study on recovery room length of stay. Secondary outcomes included the change in maternal CI, fluid administration, vasopressor usage, maternal satisfaction, and adequacy of surgical blockade and recovery time from motor and sensory blockade. RESULTS: The low dose group had significantly faster motor recovery times (132 [122-144] versus. 54 [48-66] min conventional versus. low-dose, respectively, P < 0.01), and a shorter recovery room stay (92 ± 21 vs 70 ± 11 min, conventional vs. low-dose, respectively, P < 0.01, 95% CI -35 to -10 min). There was no difference in CI between the conventional dose and low dose spinal groups. Both groups had a drop in CI with spinal anesthesia. The low-dose group demonstrated equivalent surgical anesthesia and block onset times compared to the conventional group. CONCLUSIONS: Low-dose spinal anesthesia provides adequate surgical anesthesia, improved recovery time, but no difference in maternal cardiac index when compared to conventional dose spinal anesthesia.NCT02046697.

High Spinal Anesthesia Enhances Anti-Inflammatory Responses in Patients Undergoing Coronary Artery Bypass Graft Surgery and Aortic Valve Replacement: Randomized Pilot Study.

BACKGROUND: Cardiac surgery induces many physiologic changes including major inflammatory and sympathetic nervous system responses. Here, we conducted a single-centre pilot study to generate hypotheses on the potential immune impact of adding high spinal anaesthesia to general anaesthesia during cardiac surgery in adults. We hypothesized that this strategy, previously shown to blunt the sympathetic response and improve pain management, could reduce the undesirable systemic inflammatory responses caused by cardiac surgery. METHODS: This prospective randomized unblinded pilot study was conducted on 14 patients undergoing cardiac surgery for coronary artery bypass grafting and/or aortic valve replacement secondary to severe aortic stenosis. The primary outcome measures examined longitudinally were serum pro-inflammatory (IL-6, IL-1b, CCL2), anti-inflammatory (IL-10, TNF-RII, IL-1Ra), acute phase protein (CRP, PTX3) and cardiovascular risk (sST2) biomarkers. RESULTS: The kinetics of pro- and anti-inflammatory biomarker was determined following surgery. All pro-inflammatory and acute phase reactant biomarker responses induced by surgical stress were indistinguishable in intensity and duration between control groups and those who also received high spinal anaesthesia. Conversely, IL-10 levels were markedly elevated in both intensity and duration in the group receiving high spinal anesthesia (p = 0.005). CONCLUSIONS: This hypothesis generating pilot study suggests that high spinal anesthesia can alter the net inflammatory response that results from cardiac surgery. In appropriately selected populations, this may add incremental benefit by dampening the net systemic inflammatory response during the week following surgery. Larger population studies, powered to assess immune, physiologic and clinical outcomes in both acute and longer term settings, will be required to better assess potential benefits of incorporating high spinal anesthesia. TRIAL REGISTRATION: ClinicalTrials.gov NCT00348920.

Anaesthesia in underdeveloped world: Present scenario and future challenges.

The overall mortality and morbidity in underdeveloped countries are still unchanged and preventable risks factors constitute the main burden. Among these, anaesthesia-related mortality is largely preventable. Various contributory factors related to human resources, technical resources, education/teaching system and other utilities needs further attention in poor income group countries. Therefore, we have made an attempt to address all these issues in this educational article and have given special reference to those factors that might gain importance in (near) future. Proper understanding of anaesthesia-related resources, their overall impact on health care system and their improvisation methods should be thoroughly evaluated for providing safer anaesthesia care in these countries which would certainly direct better outcome and consequently influence mortality.

Thoracic epidural analgesia improves pulmonary function in patients undergoing cardiac surgery.

PURPOSE: Pulmonary dysfunction commonly occurs following coronary artery bypass graft (CABG) surgery, increasing morbidity and mortality. We hypothesized that thoracic epidural anesthesia (TEA) would improve pulmonary function and would decrease complications in patients undergoing CABG surgery. METHODS: This prospective, randomized, controlled trial was conducted with Ethics Board approval. Fifty patients, undergoing CABG surgery, were randomized to the epidural group or to the patient-controlled analgesia morphine group. Patients in the epidural group received a high, thoracic epidural, preoperatively. Intraoperatively, 0.75% ropivacaine was infused, followed postoperatively, by 0.2% ropivacaine for 48 hr. Outcome measurements included: visual analogue pain scores; spirometry; atelectasis scores on chest radiographs; and the incidence of atrial fibrillation. RESULTS: Twenty-five patients were enrolled in each group. Patients in the epidural group had significantly less pain on the operative day, and for the subsequent two days. Compared to baseline, the forced expiratory volume in one second was significantly higher in the epidural group, on the first and second postoperative days (43.7 +/- 12.2% vs 36.4 +/- 12.0%, p < 0.002, and 43.3 +/- 12.5% vs 38.4 +/- 11.0%, p <0.05). There was significantly more atelectasis in the control group, four hours postoperatively (p < 0.04); however, on the third, postoperative day, the groups were similar with regards to this outcome. The incidence of atrial fibrillation was similar in both groups, and there were no complications related to the epidural. CONCLUSIONS: High TEA decreases postoperative pain and atelectasis and improves pulmonary function in patients undergoing CABG surgery. Our results support the use of TEA in this group of patients.