Which individual components of a colorectal surgery enhanced recovery program are associated with improved surgical outcomes?

BACKGROUND: Enhanced recovery programs improve surgical outcomes. However, the association of adherence to individual components and outcomes in a comprehensive enhanced recovery program remains unclear. METHODS: We performed a retrospective study of all elective colorectal surgery patients at our institution from 2019 to 2022 (n = 1,175). Data were acquired from our institution's enhanced recovery program dashboard and American College of Surgeons National Surgical Quality Improvement Program database. Traditional analyses and machine-learning classification trees were used to identify enhanced recovery program components associated with length of stay, readmissions, and complication rates. RESULTS: The average length of stay was 5.0 days, readmission rate was 12.3%, and complication rate was 32.6%. On linear regression analysis, adherence to preoperative education, regional analgesia, pre- and postoperative multimodal analgesia, no nasogastric tube, early mobilization, early regular diet, early discontinuation of maintenance intravenous fluids, postoperative venous thromboembolism prophylaxis, and early Foley catheter removal were associated with an decrease in length of stay by 0.7-7.1 days (P < .05). Patients who adhered to no prolonged fasting had a 4.1% decrease in readmission rate (P = .04). Patients who adhered to no nasogastric tube, early mobilization, early regular diet, postoperative multimodal analgesia, and discontinuation of maintenance intravenous fluids had decreases in complication rates ranging from 7.0 to 28.2% (P < .001). Machine learning demonstrated that no nasogastric tube and discontinuation of maintenance intravenous fluids were significant predictors of shorter length of stay and no nasogastric tube and early mobilization were significant predictors of reduced complication rates. CONCLUSIONS: Although multiple components were associated outcomes, no nasogastric tube, early mobilization, early regular diet, postoperative multimodal analgesia, and early discontinuation of maintenance intravenous fluids were associated with more than 1 outcome. Focusing on these components may make enhanced recovery program implementation more feasible for resource-limited hospitals.

Providers' and survivors' perspectives on the availability and accessibility of surgery in gastrointestinal cancer care.

BACKGROUND: Surgery is essential for gastrointestinal (GI) cancer treatment. Many patients lack access to surgical care that optimizes outcomes. Scarce availability and/or low accessibility of appropriate resources may be the reason for this, especially in economically disadvantaged areas. This study aimed to investigate providers' and survivors' perspectives on barriers and facilitators to the availability and accessibility of surgical care. METHODS: Semistructured interviews informed by surgical disparities and access-to-care conceptual frameworks with purposively selected GI cancer providers and survivors in Alabama and Mississippi were conducted. Survivors were within 3 years of diagnosis of stage I to III esophageal, pancreatic, or colorectal cancer. Transcripts were analyzed using inductive thematic and content analysis techniques. Intercoder agreement was reached at 90 %. RESULTS: The 27 providers included surgeons (n = 11), medical oncologists (n = 2), radiation oncologists (n = 2), a primary care physician (n = 1), nurses (n = 8), and patient navigators (n = 3). This study included 36 survivors with ages ranging from 44 to 87 years. Of the 36 survivors, 21 (58.3 %) were male, and 11 (30.6 %) identified as Black. Responses were grouped into 3 broad categories: (i) transportation/geographic location, (ii) specialized care/testing, and (iii) patient-/provider-related factors. The barriers included lack and cost of transportation, reluctance to travel because of uneasiness with urban centers, low availability of specialized care, overburdened referral centers, provider-related referral biases, and low health literacy. Facilitators included availability of charitable aid, centralizing multidisciplinary care, and efficient appointment scheduling. CONCLUSION: In the Deep South, barriers and facilitators to the availability and accessibility of GI surgical cancer care were identified at the health system, provider, and patient levels, especially for rural residents. Our data suggest targets for improving the use of surgery in GI cancer care.

Preoperative Education is Associated with Adherence to Downstream Components and Outcomes in a Colorectal Surgery Enhanced Recovery Program.

Objective: This study evaluated the association between preoperative education and adherence to downstream components of enhanced recovery programs (ERPs) and surgical outcomes among patients undergoing elective colorectal surgery. Background: ERPs improve outcomes for surgical patients. While preoperative education is an essential component of ERPs, its relationship with other components is unclear. Methods: This was a retrospective cohort study of all ERP patients undergoing elective colorectal surgery from 2019 to 2022. Our institutional ERP database was linked with American College of Surgeons National Surgical Quality Improvement Program data and stratified by adherence to preoperative education. Primary outcomes included adherence to individual ERP components and secondary outcomes included high-level ERP adherence (>70% of components), length of stay (LOS), readmissions, and 30-day complications. Results: A total of 997 patients were included. The mean (SD) age was 56.5 (15.8) years, 686 (57.3%) were female, and 717 (71.9%) were white. On adjusted analysis, patients who received preoperative education (n = 877, 88%) had higher adherence rates for the following ERP components: no prolonged fasting (estimate = +19.6%; P < 0.001), preoperative blocks (+8.0%; P = 0.02), preoperative multimodal analgesia (+18.0%; P < 0.001), early regular diet (+15.9%; P < 0.001), and postoperative multimodal analgesia (+6.4%; P < 0.001). High-level ERP adherence was 13.4% higher (P < 0.01) and LOS was 2.0 days shorter (P < 0.001) for those who received preoperative education. Classification and regression tree analysis identified preoperative education as the first-level predictor for adherence to early regular diet, the second-level predictor for LOS, and the third-level predictor for ERP high-level adherence. Conclusion: Preoperative education is associated with adherence to ERP components and improved surgical outcomes.

Orthopaedic Wire Debridement: A Novel Surgical Technique for Hypergranulated Burn Wounds.

The burn wound healing process can be protracted due to various factors, including burn depth, infection and hypergranulation. Hypergranulation impedes epithelialisation macroscopically by preventing cellular migration across the wound bed and microscopically through cell-to-cell signal interferences. Debridement, which is the act of removing necrotic tissue, hypergranulation, slough and foreign debris from the wound in order to expose the underlying viable bed, can be achieved using various techniques. This aids with wound bed preparation to facilitate and expedite healing. In this article, we present a novel surgical debridement technique using a malleable orthopaedic cerclage wire for the management of a hypergranulated burn wound.

Amoxycillin/Clavulanic acid monotherapy in complicated paediatric appendicitis: Good enough?

BACKGROUND: Antibiotic choice for complicated appendicitis should be based on both microbiological effectiveness as well as ease of administration and cost especially in lower resourced settings. Data is limited on comparative morbidity outcomes for antibiotics with similar microbiological spectrum of activity. Incidence and morbidity of surgical site infection after appendectomy for complicated appendicitis was assessed after protocol change from triple antibiotic (ampicillin, gentamycin, and metronidazole) regimen to single agent (amoxycillin/clavulanic acid). METHODS: Surgical site infection (SSI) rate, relook surgery rate and length of hospital stay were retrospectively compared in patients treated for acute appendicitis preceding (2014, 2015; "triple-therapy, TT") and following (2017, 2018; "single agent, SA") antibiotic protocol change. RESULTS: The rate of complicated appendicitis was similar between groups; 72.6% in TT and 66% in SA (p = 0.239). Significantly, SSI occurred in 22.7% of the SA group compared to 13.3% in TT group (OR 1.920, 95% CI 1.000-3.689, p = 0.048). Use of laparoscopy increased from 31% in TT to 89% in SA, but with subgroup analysis this was not associated with increased SSI (17.3% in open and 20.6% in laparoscopic; OR 0.841, 95% CI 0.409-1.728, p = 0.637). Relook rate (OR 1.444, 95% CI 0.595-3.507, p = 0.093) length of hospital stay (U = 6859, z = -1.163, p = 0.245), and ICU admission (U = 7683, z = 0.634 p = 0.522) were equivocal. Neither group had mortalities. CONCLUSIONS: Despite increased SSI with SA, overall morbidity relating to ICU admission, relook rate and length of hospital stay was similar in both groups. More prospective research is required to confirm equivalent overall morbidity and that single agent therapy is more cost-effective with acceptable clinical outcomes.

Bioacoustic classification of avian calls from raw sound waveforms with an open-source deep learning architecture.

The use of autonomous recordings of animal sounds to detect species is a popular conservation tool, constantly improving in fidelity as audio hardware and software evolves. Current classification algorithms utilise sound features extracted from the recording rather than the sound itself, with varying degrees of success. Neural networks that learn directly from the raw sound waveforms have been implemented in human speech recognition but the requirements of detailed labelled data have limited their use in bioacoustics. Here we test SincNet, an efficient neural network architecture that learns from the raw waveform using sinc-based filters. Results using an off-the-shelf implementation of SincNet on a publicly available bird sound dataset (NIPS4Bplus) show that the neural network rapidly converged reaching accuracies of over 65% with limited data. Their performance is comparable with traditional methods after hyperparameter tuning but they are more efficient. Learning directly from the raw waveform allows the algorithm to select automatically those elements of the sound that are best suited for the task, bypassing the onerous task of selecting feature extraction techniques and reducing possible biases. We use publicly released code and datasets to encourage others to replicate our results and to apply SincNet to their own datasets; and we review possible enhancements in the hope that algorithms that learn from the raw waveform will become useful bioacoustic tools.

Mortality predispositions of conifers across western USA.

Conifer mortality rates are increasing in western North America, but the physiological mechanisms underlying this trend are not well understood. We examined tree-ring-based radial growth along with stable carbon (C) and oxygen (O) isotope composition (δ13 C and δ18 O, respectively) of dying and surviving conifers at eight old-growth forest sites across a strong moisture gradient in the western USA to retrospectively investigate mortality predispositions. Compared with surviving trees, lower growth of dying trees was detected at least one decade before mortality at seven of the eight sites. Intrinsic water-use efficiency increased over time in both dying and surviving trees, with a weaker increase in dying trees at five of the eight sites. C starvation was a strong correlate of conifer mortality based on a conceptual model incorporating growth, δ13 C, and δ18 O. However, this approach does not capture processes that occur in the final months of survival. Ultimately, C starvation may lead to increased mortality vulnerability, but hydraulic failure or biotic attack may dominate the process during the end stages of mortality in these conifers.

Giant cacti: isotopic recorders of climate variation in warm deserts of the Americas.

The plant family Cactaceae is considered among the most threatened groups of organisms on the planet. The threatened status of the cacti family has created a renewed interest in the highly evolved physiological and morphological traits that underpin their persistence in some of the harshest subtropical environments in the Americas. Among the most important anatomical features of cacti is the modification of leaves into spines, and previous work has shown that the stable isotope chemistry of cacti spines records potential variations in stem water balance, stress, and Crassulacean acid metabolism (CAM). We review the opportunities, challenges, and pitfalls in measuring δ 13C, δ 2H, and δ 18O ratios captured in spine tissues that potentially reflect temporal and spatial patterns of stomatal conductance, internal to atmospheric CO2 partial pressures, and subsequent patterns of photosynthetic gas exchange. We then evaluate the challenges in stable isotope analysis in spine tissues related to variation in CAM expression, stem water compartmentalization, and spine whole-tissue composition among other factors. Finally, we describe how the analysis of all three isotopes can be used in combination to provide potentially robust analysis of photosynthetic function in cacti, and other succulent-stemmed taxa across broad spatio-temporal environmental gradients.

Hepatitis E virus: Western Cape, South Africa.

AIM: To conduct a prospective assessment of anti-hepatitis E virus (HEV) IgG seroprevalence in the Western Cape Province of South Africa in conjunction with evaluating risk factors for exposure. METHODS: Consenting participants attending clinics and wards of Groote Schuur, Red Cross Children's Hospital and their affiliated teaching hospitals in Cape Town, South Africa, were sampled. Healthy adults attending blood donor clinics were also recruited. Patients with known liver disease were excluded and all major ethnic/race groups were included to broadly represent local demographics. Relevant demographic data was captured at the time of sampling using an interviewer-administered confidential questionnaire. Human immunodeficiency virus (HIV) status was self-disclosed. HEV IgG testing was performed using the Wantai® assay. RESULTS: HEV is endemic in the region with a seroprevalence of 27.9% (n = 324/1161) 95%CI: 25.3%-30.5% (21.9% when age-adjusted) with no significant differences between ethnic groups or HIV status. Seroprevalence in children is low but rapidly increases in early adulthood. With univariate analysis, age ≥ 30 years old, pork and bacon/ham consumption suggested risk. In the multivariate analysis, the highest risk factor for HEV IgG seropositivity (OR = 7.679, 95%CI: 5.38-10.96, P < 0.001) was being 30 years or older followed by pork consumption (OR = 2.052, 95%CI: 1.39-3.03, P < 0.001). A recent clinical case demonstrates that HEV genotype 3 may be currently circulating in the Western Cape. CONCLUSION: Hepatitis E seroprevalence was considerably higher than previously thought suggesting that hepatitis E warrants consideration in any patient presenting with an unexplained hepatitis in the Western Cape, irrespective of travel history, age or ethnicity.

Progress in Australian dendroclimatology: Identifying growth limiting factors in four climate zones.

Dendroclimatology can be used to better understand past climate in regions such as Australia where instrumental and historical climate records are sparse and rarely extend beyond 100years. Here we review 36 Australian dendroclimatic studies which cover the four major climate zones of Australia; temperate, arid, subtropical and tropical. We show that all of these zones contain tree and shrub species which have the potential to provide high quality records of past climate. Despite this potential only four dendroclimatic reconstructions have been published for Australia, one from each of the climate zones: A 3592year temperature record for the SE-temperate zone, a 350year rainfall record for the Western arid zone, a 140year rainfall record for the northern tropics and a 146year rainfall record for SE-subtropics. We report on the spatial distribution of tree-ring studies, the environmental variables identified as limiting tree growth in each study, and identify the key challenges in using tree-ring records for climate reconstruction in Australia. We show that many Australian species have yet to be tested for dendroclimatological potential, and that the application of newer techniques including isotopic analysis, carbon dating, wood density measurements, and anatomical analysis, combined with traditional ring-width measurements should enable more species in each of the climate zones to be used, and long-term climate records to be developed across the entire continent.

Stable isotopes in leaf water of terrestrial plants.

Leaf water contains naturally occurring stable isotopes of oxygen and hydrogen in abundances that vary spatially and temporally. When sufficiently understood, these can be harnessed for a wide range of applications. Here, we review the current state of knowledge of stable isotope enrichment of leaf water, and its relevance for isotopic signals incorporated into plant organic matter and atmospheric gases. Models describing evaporative enrichment of leaf water have become increasingly complex over time, reflecting enhanced spatial and temporal resolution. We recommend that practitioners choose a model with a level of complexity suited to their application, and provide guidance. At the same time, there exists some lingering uncertainty about the biophysical processes relevant to patterns of isotopic enrichment in leaf water. An important goal for future research is to link observed variations in isotopic composition to specific anatomical and physiological features of leaves that reflect differences in hydraulic design. New measurement techniques are developing rapidly, enabling determinations of both transpired and leaf water δ(18) O and δ(2) H to be made more easily and at higher temporal resolution than previously possible. We expect these technological advances to spur new developments in our understanding of patterns of stable isotope fractionation in leaf water.

The effects of α-cellulose extraction and blue-stain fungus on retrospective studies of carbon and oxygen isotope variation in live and dead trees.

Tree-ring carbon and oxygen isotope ratios from live and recently dead trees may reveal important mechanisms of tree mortality. However, wood decay in dead trees may alter the δ(13)C and δ(18)O values of whole wood obscuring the isotopic signal associated with factors leading up to and including physiological death. We examined whole sapwood and α-cellulose from live and dead specimens of ponderosa pine (Pinus ponderosa), one-seed juniper (Juniperous monosperma), piñon pine (Pinus edulis) and white fir (Abies concolor), including those with fungal growth and beetle frass in the wood, to determine if α-cellulose extraction is necessary for the accurate interpretation of isotopic compositions in the dead trees. We found that the offset between the δ(13)C or δ(18)O values of α-cellulose and whole wood was the same for both live and dead trees across a large range of inter-annual and regional climate differences. The method of α-cellulose extraction, whether Leavitt-Danzer or Standard Brendel modified for small samples, imparts significant differences in the δ(13)C (up to 0.4‰) and δ(18) O (up to 1.2‰) of α-cellulose, as reported by other studies. There was no effect of beetle frass or blue-stain fungus (Ophiostoma) on the δ(13)C and δ(18)O of whole wood or α-cellulose. The relationships between whole wood and α-cellulose δ(13)C for ponderosa, piñon and juniper yielded slopes of ~1, while the relationship between δ(18)O of whole wood and α-cellulose was less clear. We conclude that there are few analytical or sampling obstacles to retrospective studies of isotopic patterns of tree mortality in forests of the western United States.

Seasonal photosynthetic gas exchange and water-use efficiency in a constitutive CAM plant, the giant saguaro cactus (Carnegiea gigantea).

Crassulacean acid metabolism (CAM) and the capacity to store large quantities of water are thought to confer high water use efficiency (WUE) and survival of succulent plants in warm desert environments. Yet the highly variable precipitation, temperature and humidity conditions in these environments likely have unique impacts on underlying processes regulating photosynthetic gas exchange and WUE, limiting our ability to predict growth and survival responses of desert CAM plants to climate change. We monitored net CO(2) assimilation (A(net)), stomatal conductance (g(s)), and transpiration (E) rates periodically over 2 years in a natural population of the giant columnar cactus Carnegiea gigantea (saguaro) near Tucson, Arizona USA to investigate environmental and physiological controls over carbon gain and water loss in this ecologically important plant. We hypothesized that seasonal changes in daily integrated water use efficiency (WUE(day)) in this constitutive CAM species would be driven largely by stomatal regulation of nighttime transpiration and CO(2) uptake responding to shifts in nighttime air temperature and humidity. The lowest WUE(day) occurred during time periods with extreme high and low air vapor pressure deficit (D(a)). The diurnal with the highest D(a) had low WUE(day) due to minimal net carbon gain across the 24 h period. Low WUE(day) was also observed under conditions of low D(a); however, it was due to significant transpiration losses. Gas exchange measurements on potted saguaro plants exposed to experimental changes in D(a) confirmed the relationship between D(a) and g(s). Our results suggest that climatic changes involving shifts in air temperature and humidity will have large impacts on the water and carbon economy of the giant saguaro and potentially other succulent CAM plants of warm desert environments.

Past climate changes and ecophysiological responses recorded in the isotope ratios of saguaro cactus spines.

The stable isotope composition of spines produced serially from the apex of columnar cacti has the potential to be used as a record of changes in climate and physiology. To investigate this potential, we measured the delta(18)O, delta(13)C and F(14)C values of spines from a long-lived columnar cactus, saguaro (Carnegiea gigantea). To determine plant age, we collected spines at 11 different heights along one rib from the stem apex (3.77 m height) to the base of a naturally occurring saguaro. Fractions of modern carbon (F(14)C) ranged from 0.9679 to 1.5537, which is consistent with ages between 1950 and 2004. We observed a very strong positive correlation (r = 0.997) between the F(14)C age of spines and the age of spines determined from direct and repeated height measurements taken on this individual over the past 37 years. A series of 96 spines collected from this individual had delta(18)O values ranging from 38 per thousand to 50 per thousand [Vienna standard mean ocean water (VSMOW)] and delta(13)C values from -11.5 per thousand to -8.5 per thousand [Vienna Peedee belemnite (VPDB)]. The delta(18)O and delta(13)C values of spines were positively correlated (r = 0.45, P < 0.0001) and showed near-annual oscillations over the approximately 15-year record. This pattern suggests that seasonal periods of reduced evaporative demand or greater precipitation input may correspond to increased daytime CO(2) uptake. The lowest delta(18)O and delta(13)C values of spines observed occurred during the 1983 and 1993 El Niño years, suggesting that the stable isotope composition recorded in spine tissue may serve as a proxy for these climate events. We compared empirical models and data from potted experimental cacti to validate these observations and test our hypotheses. The isotopic records presented here are the first ever reported from a chronosequence of cactus spines and demonstrate that tissues of columnar cacti, and potentially other long-lived succulents, may contain a record of past physiological and climatic variation.

Precipitation pulse use by an invasive woody legume: the role of soil texture and pulse size.

Plant metabolic activity in arid and semi-arid environments is largely tied to episodic precipitation events or "pulses". The ability of plants to take up and utilize rain pulses during the growing season in these water-limited ecosystems is determined in part by pulse timing, intensity and amount, and by hydrological properties of the soil that translate precipitation into plant-available soil moisture. We assessed the sensitivity of an invasive woody plant, velvet mesquite (Prosopis velutina Woot.), to large (35 mm) and small (10 mm) isotopically labeled irrigation pulses on two contrasting soil textures (sandy-loam vs. loamy-clay) in semi-desert grassland in southeastern Arizona, USA. Predawn leaf water potential (psi(pd)), the isotopic abundance of deuterium in stem water (deltaD), the abundance of 13C in soluble leaf sugar (delta13C), and percent volumetric soil water content (theta(v)) were measured prior to irrigation and repeatedly for 2 weeks following irrigation. Plant water potential and the percent of pulse water present in the stem xylem indicated that although mesquite trees on both coarse- and fine-textured soils quickly responded to the large irrigation pulse, the magnitude and duration of this response substantially differed between soil textures. After reaching a maximum 4 days after the irrigation, the fraction of pulse water in stem xylem decreased more rapidly on the loamy-clay soil than the sandy-loam soil. Similarly, on both soil textures mesquite significantly responded to the 10-mm pulse. However, the magnitude of this response was substantially greater for mesquite on the sandy-loam soil compared to loamy-clay soil. The relationship between psi(pd) and delta13C of leaf-soluble carbohydrates over the pulse period did not differ between plants at the two sites, indicating that differences in photosynthetic response of mesquite trees to the moisture pulses was a function of soil water availability within the rooting zone rather than differences in plant biochemical or physiological constraints. Patterns of resource acquisition by mesquite during the dynamic wetting-drying cycle following rainfall pulses is controlled by a complex interaction between pulse size and soil hydraulic properties. A better understanding of how this interaction affects plant water availability and photosynthetic response is needed to predict how grassland structure and function will respond to climate change.

Response of net ecosystem gas exchange to a simulated precipitation pulse in a semi-arid grassland: the role of native versus non-native grasses and soil texture.

Physiological activity and structural dynamics in arid and semi-arid ecosystems are driven by discrete inputs or "pulses" of growing season precipitation. Here we describe the short-term dynamics of ecosystem physiology in experimental stands of native (Heteropogon contortus) and invasive (Eragrostis lehmanniana) grasses to an irrigation pulse across two geomorphic surfaces with distinctly different soils: a Pleistocene-aged surface with high clay content in a strongly horizonated soil, and a Holocene-aged surface with low clay content in homogenously structured soils. We evaluated whole-ecosystem and leaf-level CO2 and H2O exchange, soil CO2 efflux, along with plant and soil water status to understand potential constraints on whole-ecosystem carbon exchange during the initiation of the summer monsoon season. Prior to the irrigation pulse, both invasive and native grasses had less negative pre-dawn water potentials (Psipd), greater leaf photosynthetic rates (Anet) and stomatal conductance (gs), and greater rates of net ecosystem carbon exchange (NEE) on the Pleistocene surface than on the Holocene. Twenty-four hours following the experimental application of a 39 mm irrigation pulse, soil CO2 efflux increased leading to all plots losing CO2 to the atmosphere over the course of a day. Invasive species stands had greater evapotranspiration rates (ET) immediately following the precipitation pulse than did native stands, while maximum instantaneous NEE increased for both species and surfaces at roughly the same rate. The differential ET patterns through time were correlated with an earlier decline in NEE in the invasive species as compared to the native species plots. Plots with invasive species accumulated between 5% and 33% of the carbon that plots with the native species accumulated over the 15-day pulse period. Taken together, these results indicate that system CO2 efflux (both the physical displacement of soil CO2 by water along with plant and microbial respiration) strongly controls whole-ecosystem carbon exchange during precipitation pulses. Since CO2 and H2O loss to the atmosphere was partially driven by species effects on soil microclimate, understanding the mechanistic relationships between the soil characteristics, plant ecophysiological responses, and canopy structural dynamics will be important for understanding the effects of shifting precipitation and vegetation patterns in semi-arid environments.