Assessing the Oxidative Potential of Outdoor PM2.5 in Wintertime Fairbanks, Alaska.

The oxidative potential (OP) of outdoor PM2.5 in wintertime Fairbanks, Alaska, is investigated and compared to those in wintertime Atlanta and Los Angeles. Approximately 40 filter samples collected in January-February 2022 at a Fairbanks residential site were analyzed for OP utilizing dithiothreitol-depletion (OPDTT) and hydroxyl-generation (OPOH) assays. The study-average PM2.5 mass concentration was 12.8 µg/m3, with a 1 h average maximum of 89.0 µg/m3. Regression analysis, correlations with source tracers, and contrast between cold and warmer events indicated that OPDTT was mainly sensitive to copper, elemental carbon, and organic aerosol from residential wood burning, and OPOH to iron and organic aerosol from vehicles. Despite low photochemically-driven oxidation rates, the water-soluble fraction of OPDTT was unusually high at 77%, mainly from wood burning emissions. In contrast to other locations, the Fairbanks average PM2.5 mass concentration was higher than Atlanta and Los Angeles, whereas OPDTT in Fairbanks and Atlanta were similar, and Los Angeles had the highest OPDTT and OPOH. Site differences were observed in OP when normalized by both the volume of air sampled and the particle mass concentration, corresponding to exposure and the intrinsic health-related properties of PM2.5, respectively. The sensitivity of OP assays to specific aerosol components and sources can provide insights beyond the PM2.5 mass concentration when assessing air quality.

Indoor-Outdoor Oxidative Potential of PM2.5 in Wintertime Fairbanks, Alaska: Impact of Air Infiltration and Indoor Activities.

The indoor air quality of a residential home during winter in Fairbanks, Alaska, was investigated and contrasted with outdoor levels. Twenty-four-hour average indoor and outdoor filter samples were collected from January 17 to February 25, 2022, in a residential area with high outdoor PM2.5 concentrations. The oxidative potential of PM2.5 was determined using the dithiothreitol-depletion assay (OPDTT). For the unoccupied house, the background indoor-to-outdoor (I/O) ratio of mass-normalized OP (OPmDTT), a measure of the intrinsic health-relevant properties of the aerosol, was less than 1 (0.53 ± 0.37), implying a loss of aerosol toxicity as air was transported indoors. This may result from transport and volatility losses driven by the large gradients in temperature (average outdoor temperature of -19°C/average indoor temperature of 21 °C) or relative humidity (average outdoor RH of 78%/average indoor RH of 11%), or both. Various indoor activities, including pellet stove use, simple cooking experiments, incense burning, and mixtures of these activities, were conducted. The experiments produced PM2.5 with a highly variable OPmDTT. PM2.5 from cooking emissions had the lowest OP values, while pellet stove PM2.5 had the highest. Correlations between volume-normalized OPDTT (OPvDTT), relevant to exposure, and indoor PM2.5 mass concentration during experiments were much lower compared to those in outdoor environments. This suggests that mass concentration alone can be a poor indicator of possible adverse effects of various indoor emissions. These findings highlight the importance of considering both the quantity of particles and sources (chemical composition), as health metrics for indoor air quality.

Overview of the Alaskan Layered Pollution and Chemical Analysis (ALPACA) Field Experiment.

The Alaskan Layered Pollution And Chemical Analysis (ALPACA) field experiment was a collaborative study designed to improve understanding of pollution sources and chemical processes during winter (cold climate and low-photochemical activity), to investigate indoor pollution, and to study dispersion of pollution as affected by frequent temperature inversions. A number of the research goals were motivated by questions raised by residents of Fairbanks, Alaska, where the study was held. This paper describes the measurement strategies and the conditions encountered during the January and February 2022 field experiment, and reports early examples of how the measurements addressed research goals, particularly those of interest to the residents. Outdoor air measurements showed high concentrations of particulate matter and pollutant gases including volatile organic carbon species. During pollution events, low winds and extremely stable atmospheric conditions trapped pollution below 73 m, an extremely shallow vertical scale. Tethered-balloon-based measurements intercepted plumes aloft, which were associated with power plant point sources through transport modeling. Because cold climate residents spend much of their time indoors, the study included an indoor air quality component, where measurements were made inside and outside a house to study infiltration and indoor sources. In the absence of indoor activities such as cooking and/or heating with a pellet stove, indoor particulate matter concentrations were lower than outdoors; however, cooking and pellet stove burns often caused higher indoor particulate matter concentrations than outdoors. The mass-normalized particulate matter oxidative potential, a health-relevant property measured here by the reactivity with dithiothreiol, of indoor particles varied by source, with cooking particles having less oxidative potential per mass than pellet stove particles.

Efficacy and utilization of intravascular ultrasound in office-based lower extremity endovascular interventions for peripheral arterial disease.

OBJECTIVES: Intravascular ultrasound (IVUS) is a uniquely objective but underutilized imaging modality in the interventional treatment of peripheral arterial disease treatment. IVUS has been shown to improve device size selection and diagnose occult pathology difficult to see with routine angiography. We hypothesize that the use of IVUS in lower extremity endovascular intervention improves accuracy in stent and balloon size selection and minimizes contrast use. METHODS: This is a retrospective case series performed at a single-institution outpatient center by two vascular surgeons from July 2016 through July 2017. We identified 94 total IVUS-assisted procedures. We collected data regarding demographics, balloon and stent size, IVUS-determined vessel diameter, pre-procedure and post-procedure ABI values, and contrast used during the procedure. An independent core laboratory was further utilized to characterize all IVUS and angiographic size vessel measurements. RESULTS: For the 94 lower extremity IVUS-assisted interventions, the average patient age was 70±9 years old, with an average contrast use of 37.1 mL of Omnipaque 300. There was substantial improvement in pre- and post-procedure ABI (0.7±0.23 to 0.94±0.21). On analysis of average intraluminal IVUS vessel diameter to balloon angioplasty used, we had a correlation in size of 0.96±0.16 in our series. Additionally, in eight instances IVUS allowed for identification of a flow-limiting dissection with subsequent stenting. CONCLUSIONS: Routine use of IVUS offers a powerful diagnostic paradigm that has the potential to significantly decrease contrast use and to improve objectivity in choosing appropriate vascular tools to maximize intra-procedural efficacy. The discovery of adverse findings not initially noticed on angiography further reinforces the value of IVUS utilization.

The impact of obesity and morbid obesity on urgent/emergency colorectal resections: a regional database analysis.

BACKGROUND: The obesity rate is projected to reach 50% by 2030. Obesity may be modifiable prior to elective colorectal surgery, but there is no opportunity for weight loss when patients present for urgent/emergency operations. The impact of obesity focused on urgent/emergent colorectal operations has not been fully characterized. The study aim was to determine outcomes of obese patients who undergo urgent/emergency colorectal surgery and differences when compared with elective outcomes. METHODS: This is a retrospective cohort study of 30-day outcomes for normal (BMI 18.5-25), obese (BMI 30-39.9), and morbidly obese (BMI > 40) patients in the Michigan Surgical Quality Collaborative between 1/1/2009 and 12/31/2018. Propensity score weighting was used to derive adjusted rates for overall morbidity, mortality, and specific complications. Primary outcome was postoperative complications (any morbidity). RESULTS: The study included 5268 urgent/emergency and 10,414 elective colorectal surgery patients. Postoperative complications were significantly more common in morbidly obese and obese than the normal BMI group for both urgent/emergency (morbidly obese 42.76% vs 33.75%, p = 0.003; obese 36.46% vs 33.75%, p = 0.043) and elective (morbidly obese 18.17% vs 13.36%, p = 0.004; obese 15.45% vs 13.36%, p = 0.011) operations. Surgical site infections are were significantly more common in morbidly obese and obese BMI groups as compared to normal BMI for both urgent/emergency and elective cases. Mortality was significantly higher in the morbidly obese (14.93% vs 11.44%, p = 0.013) but not obese BMI groups as compared to the normal BMI group for urgent/emergency cases. Mortality for all groups undergoing elective operations was < 1% and with no significant differences. CONCLUSIONS: Morbid obesity and obesity are associated with complications that are largely driven by surgical site infections after both urgent/emergency and elective colorectal surgery. Obesity is a risk factor difficult to modify prior to urgent/emergency surgery. Managing complications related to obesity after colorectal surgery will be a continued challenge with projected increasing obesity rates.

A Single Institution Propensity Score Weighted Analysis of Time to Chemotherapy After Minimally Invasive Versus Open Colorectal Surgery.

BACKGROUND: Oncologic outcomes for colon cancer are optimal when chemotherapy is started within 6 to 8 weeks after surgery. The study objective was to investigate the impact of operative modality and urgency on the time interval from surgery to adjuvant chemotherapy. METHODS: This is a retrospective institutional tumor registry cohort study of open and laparoscopic/robotic colorectal resections for stage II-IV cancer between April 2010 and January 2018. Primary outcome was time from surgery to chemotherapy. Predictor variables were adjusted for imbalances by propensity score weighting. RESULTS: A total of 220 patients met inclusion criteria: 171 elective (108 laparoscopic/robotic and 63 open) and 49 urgent colectomies. After propensity score weighting, there was no significant difference in time to chemotherapy between elective minimally invasive and open surgical approaches (48 days vs. 58 days, P = .187). Only 68.9% of minimally invasive and 50.8% of open colectomy patients started chemotherapy within 8 weeks of surgery. There was a significant difference (P = .037) among surgical sites with rectal resections having the longest (55 days), and right colectomies having the shortest (46 days), time to chemotherapy. Patients who had urgent operations had significantly longer hospital length of stay (P < .001) and higher post-discharge emergency department visit rates (P < .001) than the elective operation group. However, there was no significant difference in time to chemotherapy. DISCUSSION: Neither operative modality nor operative urgency resulted in a significant difference in postoperative time to initiating chemotherapy. Future efforts should be focused on identifying postoperative recovery criteria and optimum multidisciplinary communication methods that allow recovered patients to start chemotherapy sooner.

A Single-Institution Analysis of Targeted Colorectal Surgery Enhanced Recovery Pathway Strategies That Decrease Readmissions.

BACKGROUND: Decreasing readmissions is an important quality improvement strategy. Targeted interventions that effectively decrease readmissions have not been fully investigated and standardized. OBJECTIVE: The purpose of this study was to assess the effectiveness of interventions designed to decrease readmissions after colorectal surgery. DESIGN: This was a retrospective comparison of patients before and after the implementation of interventions. SETTING: This study was conducted at a single institution dedicated enhanced recovery pathway colorectal surgery service. PATIENTS: The study group received quality review interventions that were designed to decrease readmissions: preadmission class upgrades, a mobile phone app, a pharmacist-led pain management strategy, and an early postdischarge clinic. The control group was composed of enhanced recovery patients before the interventions. Propensity score weighting was used to adjust patient characteristics and predictors for imbalances. MAIN OUTCOME MEASURE: The primary outcome was 30-day readmissions. Secondary outcomes included emergency department visits. RESULTS: There were 1052 patients in the preintervention group and 668 patients in the postintervention group. After propensity score weighting, the postintervention cohort had a significantly lower readmission rate (9.98% vs 17.82%, p < 0.001) and emergency department visit rate (14.58% vs 23.15%, p < 0.001) than the preintervention group, and surgical site infection type I/II was significantly decreased as a readmission diagnosis (9.46% vs 2.43%, p = 0.043). Median time to readmission was 6 (interquartile 3-11) days in the preintervention group and 8 (3-17) days in the postintervention group (p = 0.21). Ileus, acute kidney injury, and surgical site infection type III were common reasons for readmissions and emergency department visits. LIMITATIONS: A single-institution study may not be generalizable. CONCLUSION: Readmission bundles composed of targeted interventions are associated with a decrease in readmissions and emergency department visits after enhanced recovery colorectal surgery. Bundle composition may be institution dependent. Further study and refinement of bundle components are required as next-step quality metric improvements. See Video Abstract at http://links.lww.com/DCR/B849. ANLISIS EN UNA SOLA INSTITUCIN DE LAS CIRUGAS COLORECTALES CON VAS DE RECUPERACIN DIRIGIDA AUMENTADA QUE REDUCEN LOS REINGRESOS: ANTECEDENTES:La reducción de los reingresos es una importante estrategia de mejora de la calidad. Las intervenciones dirigidas que reducen eficazmente los reingresos no se han investigado ni estandarizado por completo.OBJETIVO:El propósito de este estudio fue evaluar la efectividad de las intervenciones diseñadas para disminuir los reingresos después de la cirugía colorrectal.DISEÑO:Comparación retrospectiva de pacientes antes y después de la implementación de las intervenciones.ESCENARIO:Una sola institución dedicada al Servicio de cirugía colorrectal con vías de recuperación dirigida aumentadaPACIENTES:El grupo de estudio recibió intervenciones de revisión de calidad que fueron diseñadas para disminuir los reingresos: actualizaciones de clases previas a la admisión, una aplicación para teléfono móvil, una estrategia de manejo del dolor dirigida por farmacéuticos y alta temprana de la clínica. El grupo de control estaba compuesto por pacientes con recuperación mejorada antes de las intervenciones. Se utilizó la ponderación del puntaje de propensión para ajustar las características del paciente y los predictores de los desequilibrios.PARÁMETRO DE RESULTADO PRINCIPAL:El resultado primario fueron los reingresos a los 30 días. Los resultados secundarios incluyeron visitas al servicio de urgencias.RESULTADOS:Hubo 1052 pacientes en el grupo de preintervención y 668 pacientes en el grupo de posintervención. Después de la ponderación del puntaje de propensión, la cohorte posterior a la intervención tuvo una tasa de reingreso significativamente menor (9,98% frente a 17,82%, p <0,001) y una tasa de visitas al servicio de urgencias (14,58% frente a 23,15%, p <0,001) que el grupo de preintervención y la infección del sitio quirúrgico tipo I / II se redujo significativamente como diagnóstico de reingreso (9,46% frente a 2,43%, p = 0,043). La mediana de tiempo hasta la readmisión fue de 6 [IQR 3, 11] días en el grupo de preintervención y de 8 [3, 17] días en el grupo de posintervención (p = 0,21). El íleo, la lesión renal aguda y la infección del sitio quirúrgico tipo III fueron motivos frecuentes de reingresos y visitas al servicio de urgencias.LIMITACIONES:El estudio de una sola institución puede no ser generalizable.CONCLUSIÓNES:Los paquetes de readmisión compuestos por intervenciones dirigidas se asocian con una disminución en las readmisiones y las visitas al departamento de emergencias después de una cirugía colorrectal con vías de recuperación dirigida aumentada. La composición del paquete puede depender de la institución. Se requieren más estudios y refinamientos de los componentes del paquete como siguiente paso de mejora de la métrica de calidad. Consulte Video Resumen en http://links.lww.com/DCR/B849. (Traducción-Dr Yolanda Colorado).

Postoperative Pain After Enhanced Recovery Pathway Robotic Colon and Rectal Surgery: Does Specimen Extraction Site Matter?

BACKGROUND: The current opioid crisis has motivated surgeons to critically evaluate ways to balance postoperative pain while decreasing opioid use and thereby reducing opioids available for community diversion. The longest incision for robotic colorectal surgery is the specimen extraction site incision. Intracorporeal techniques allow specimen extraction to be at any location. OBJECTIVE: This study was designed to determine whether the Pfannenstiel location is associated with less pain and opioid use than other abdominal wall specimen extraction sites. DESIGN: This was a retrospective cohort study. SETTINGS: The study was conducted with a prospectively maintained colorectal surgery database (July 2018 through October 2019). PATIENTS: Patients with enhanced recovery robotic colorectal resections with specimen extraction were included. MAIN OUTCOME MEASURES: Propensity score weighting was used to derive adjusted rates for numeric pain scores, inpatient opioid use, opioids prescribed at discharge, opioid refills after discharge, and other related outcomes. For comparing outcomes between groups, p values were calculated using weighted χ2, Fisher exact, and t tests. RESULTS: There were 137 cases (70.9%) with Pfannenstiel extraction site incisions and 56 (29.0%) at other locations (7 midline, 49 off-midline). There was no significant difference in transversus abdominis plane blocks and epidural analgesia use between groups. Numeric pain scores, overall benefit of analgesia scores, inpatient postoperative opioid use, opioids prescribed at discharge and taken after discharge, and opioid refills were not significantly different between groups. Nonopioid pain analgesics (acetaminophen, nonsteroidal anti-inflammatory drugs, and gabapentin) prescribed at discharge were significantly less in the Pfannenstiel group (90.19% vs 98.45%; p = 0.006). Postoperative complications and readmissions were not different between groups. LIMITATIONS: This study was conducted at a single institution. CONCLUSIONS: The Pfannenstiel incision as the specimen extraction site choice in minimally invasive surgery is associated with similar postoperative pain and opioid use as extraction sites in other locations for patients having robotic colorectal resections. Specimen extraction sites may be chosen based on patient factors other than pain and opioid use. See Video Abstract at http://links.lww.com/DCR/B495. DOLOR POSTOPERATORIO DESPUS DE VAS DE RECUPERACIN MEJORADA EN CIRUGA ROBTICA DE COLON Y RECTO IMPORTA EL LUGAR DE EXTRACCIN DE LA MUESTRA: ANTECEDENTES:La actual crisis de opioides ha motivado a los cirujanos a evaluar críticamente, formas para equilibrar el dolor postoperatorio, disminuyendo el uso de opioides y por lo tanto, disminuyendo opioides disponibles para el desvío comunitario. La incisión más amplia en cirugía colorrectal robótica, es la incisión del sitio de extracción de la muestra. Las técnicas intracorpóreas permiten que la extracción de la muestra se realice en cualquier sitio.OBJETIVO:El estudio fue diseñado para determinar si la ubicación del Pfannenstiel está asociada con menos dolor y uso de opioides, a otros sitios de extracción de la muestra en la pared abdominal.DISEÑO:Estudio de cohorte retrospectivo.AJUSTES:Estudio de base de datos de cirugía colorrectal mantenida prospectivamente (7/2018 a 10/2019).PACIENTES:Se incluyeron resecciones robóticas colorrectales con recuperación mejorada y extracción de muestras.PRINCIPALES MEDIDAS DE RESULTADO:Se utilizó la ponderación del puntaje de propensión para derivar las tasas ajustadas para los puntajes numéricos de dolor, uso de opioides en pacientes hospitalizados, opioides recetados al alta, recarga de opioides después del alta y otros resultados relacionados. Para comparar los resultados entre los grupos, los valores p se calcularon utilizando chi-cuadrado ponderado, exacto de Fisher y pruebas t.RESULTADOS:Hubo 137 (70,9%) casos con incisiones en el sitio de extracción de Pfannenstiel y 56 (29,0%) en otras localizaciones (7 en la línea media, 49 fuera de la línea media). No hubo diferencias significativas en los bloqueos del plano transverso del abdomen y el uso de analgesia epidural entre los grupos. Las puntuaciones numéricas de dolor, puntuaciones de beneficio general de la analgesia, uso postoperatorio de opioides en pacientes hospitalizados, opioides recetados al alta y tomados después del alta, y las recargas de opioides, no fueron significativamente diferentes entre los grupos. Los analgésicos no opioides (acetaminofén, antiinflamatorios no esteroideos, gabapentina) prescritos al alta, fueron significativamente menores en el grupo de Pfannenstiel (90,19% frente a 98,45%, p = 0,006). Las complicaciones postoperatorias y los reingresos, no fueron diferentes entre los grupos.LIMITACIONES:Una sola institución.CONCLUSIÓN:La incisión de Pfannenstiel como sitio de extracción de la muestra en cirugía mínimamente invasiva, se asocia con dolor postoperatorio y uso de opioides similar, a otros sitios de extracción en pacientes sometidos a resecciones robóticas colorrectales. Sitios de extracción de la muestra, pueden elegirse en función de factores del paciente distintos al dolor y uso de opioides. Consulte Video Resumen en http://links.lww.com/DCR/B495.).

Forest density intensifies the importance of snowpack to growth in water-limited pine forests.

Warming climate and resulting declines in seasonal snowpack have been associated with drought stress and tree mortality in seasonally snow-covered watersheds worldwide. Meanwhile, increasing forest density has further exacerbated drought stress due to intensified tree-tree competition. Using a uniquely detailed data set of population-level forest growth (n = 2,495 sampled trees), we examined how inter-annual variability in growth relates to snow volume across a range of forest densities (e.g., competitive environments) in sites spanning a broad aridity gradient across the United States. Forest growth was positively related to snowpack in water-limited forests located at low latitude, and this relationship was intensified by forest density. However, forest growth was negatively related to snowpack in a higher latitude more energy-limited forest, and this relationship did not interact with forest density. Future reductions in snowpack may have contrasting consequences, as growth may respond positively in energy-limited forests and negatively in water-limited forests; however, these declines may be mitigated by reducing stand density through forest thinning.

Recurrence of Acute Right Colon Diverticulitis Following Nonoperative Management: A Systematic Review and Meta-analysis.

BACKGROUND: There are currently no guidelines on the management of right colon diverticulitis. Treatment options have been extrapolated from the management of left-sided diverticulitis. Gaining knowledge of the risk and morbidity of diverticulitis recurrence is integral to weighing the benefit of elective surgery for right-sided diverticulitis. OBJECTIVE: The purpose of this study was to summarize the recurrence rate and the morbidity of recurrence of Hinchey classification I/II, right-sided diverticulitis following nonoperative management. DATA SOURCES: PubMed, EMBASE, and Cochrane Database of Collected Reviews were searched up to June 2019. STUDY SELECTION: Observational cohort studies evaluating outcomes following nonoperative management were reviewed. No randomized controlled trials were available. INTERVENTIONS: Intravenous antibiotics with or without percutaneous drainage of associated abscess were administered. MAIN OUTCOME MEASURES: The primary outcomes measured were the recurrence rate and morbidity associated with recurrence. Two independent investigators extracted data. The rates of recurrence were pooled by using a random-effects model. RESULTS: There were 1584 adult participants from a total of 11 studies (9 retrospective cohort and 2 prospective cohort studies) included in the analysis. Over a median follow-up period of 34.2 months, the pooled recurrence rate was 12% (95% CI, 10%-15%). Twenty of 202 patients (9.9%) required urgent surgery at the time of first recurrence. There was no mortality. Subset analysis excluding 3 studies that included percutaneous drainage as a nonoperative treatment option did not change the recurrence rate (12% (95% CI, 9%-15%)) or heterogeneity. Funnel plot assessment revealed no publication bias. LIMITATIONS: There were no randomized controlled trials available. The statistical heterogeneity was moderate (I = 46%). CONCLUSIONS: Nonoperative management of Hinchey I/II right-sided diverticulitis is safe and feasible. The recurrence rate is relatively low, and complications that require urgent operation are uncommon. PROSPERO: CRD42019131673.

The Fire and Tree Mortality Database, for empirical modeling of individual tree mortality after fire.

Wildland fires have a multitude of ecological effects in forests, woodlands, and savannas across the globe. A major focus of past research has been on tree mortality from fire, as trees provide a vast range of biological services. We assembled a database of individual-tree records from prescribed fires and wildfires in the United States. The Fire and Tree Mortality (FTM) database includes records from 164,293 individual trees with records of fire injury (crown scorch, bole char, etc.), tree diameter, and either mortality or top-kill up to ten years post-fire. Data span 142 species and 62 genera, from 409 fires occurring from 1981-2016. Additional variables such as insect attack are included when available. The FTM database can be used to evaluate individual fire-caused mortality models for pre-fire planning and post-fire decision support, to develop improved models, and to explore general patterns of individual fire-induced tree death. The database can also be used to identify knowledge gaps that could be addressed in future research.

No evidence for brown carbon formation in ambient particles undergoing atmospherically relevant drying.

Recent laboratory studies have reported the formation of light-absorbing organic carbon compounds (brown carbon, BrC) in particles undergoing drying. Atmospheric particles undergo cycles of humidification and drying during vertical transport and through daily variations in temperature and humidity, which implies particle drying could potentially be an important source of BrC globally. In this work, we investigated BrC formation in ambient particles undergoing drying at a site in the eastern United States during summer. Aerosol BrC concentrations were linked to secondary organic aerosol (SOA) formation, consistent with seasonal expectations for this region. Measurements of water-soluble organic aerosol concentrations and light absorption (365 nm) were alternated between an unperturbed channel and a channel that dried particles to 41% or 35% relative humidity (RH), depending on the system configuration. The RH maintained in the dry channels was below most ambient RH levels observed throughout the study. We did not observe BrC formation in particles that were dried to either RH level. The results were consistent across two summers, spanning ∼5 weeks of measurements that included a wide range of RH conditions and organic and inorganic aerosol loadings. This work suggests that mechanisms aside from humidification-drying cycles are more important contributors to ambient particle BrC loadings. The implications of this work on the atmospheric budget of BrC are discussed.

Liposomal Bupivacaine Transversus Abdominis Plane Block Versus Epidural Analgesia in a Colon and Rectal Surgery Enhanced Recovery Pathway: A Randomized Clinical Trial.

BACKGROUND: Multimodal pain management is an integral part of enhanced recovery pathways. The most effective pain management strategies have not been determined. OBJECTIVE: The purpose of this study was to compare liposomal bupivacaine transversus abdominis plane block with epidural analgesia in patients undergoing colorectal surgery. DESIGN: This is a single-institution, open-label randomized (1:1) trial. SETTING: This study compared liposomal bupivacaine transversus abdominis plane block with epidural analgesia in patients undergoing elective open and minimally invasive colorectal surgery in an enhanced recovery pathway. PATIENTS: Two hundred were enrolled. Following randomization, allocation, and follow-up, there were 92 patients with transversus abdominis plane block and 87 patients with epidural analgesia available for analysis. INTERVENTIONS: The interventions comprised liposomal bupivacaine transversus abdominis plane block versus epidural analgesia. MAIN OUTCOME MEASURES: The primary outcomes measured were numeric pain scores and the overall benefit of analgesia scores. RESULTS: There were no significant differences in the Numeric Pain Scale and Overall Benefit of Analgesia Score between groups. Time trend analysis revealed that patients with transversus abdominis plane block had higher numeric pain scores on the day of surgery, but that the relationship was reversed later in the postoperative period. Opioid use was significantly less in the transversus abdominis plane block group (206.84 mg vs 98.29 mg, p < 0.001). There were no significant differences in time to GI recovery, hospital length of stay, and postoperative complications. Cost was considerably more for the epidural analgesia group. LIMITATIONS: This study was conducted at a single institution. CONCLUSIONS: This randomized trial shows that perioperative pain management with liposomal bupivacaine transversus abdominis plane block is as effective as epidural analgesia and is associated with less opioid use and less cost. These data and the more favorable risk profile suggest that liposomal bupivacaine transversus abdominis plane block is a viable multimodal perioperative pain management option for this patient population in an established enhanced recovery pathway. CLINICAL TRIAL REGISTRATION: http://www.clinicaltrials.gov (NCT02591407). See Video Abstract at http://links.lww.com/DCR/A737.

Effect of the Urban Heat Island on Aerosol pH.

The urban heat island (UHI) is a widely observed phenomenon whereby urban environments have higher temperatures and different relative humidities than surrounding suburban and rural areas. Temperature (T) and relative humidity (RH) strongly affect the partitioning of semivolatile species found in the atmosphere, such as nitric acid, ammonia, and water. These species are inherently tied to aerosol pH, which is a key parameter driving some atmospheric chemical processes and environmental effects of aerosols. In this study, we characterized the effect of the UHI on aerosol pH in Baltimore, MD, and Chicago, IL. The T and RH differences that define the UHI lead to substantial differences in aerosol liquid water (ALW) content. The ALW differences produce urban aerosol pH that is systematically lower (more acidic) than rural aerosol pH for identical atmospheric composition. The UHI in Baltimore and Chicago are most intense during the summer and at night, with urban-rural aerosol pH differences in excess of 0.8 and 0.65 pH units, respectively. The UHI has been observed in cities of all sizes: the similarity of our results for cities with different climatologies and aerosol compositions suggests that these results have broad implications for chemistry occurring in and around urban atmospheres globally.