Visceral Fat as a Risk Factor for Periprosthetic Joint Infection After Total Hip and Knee Arthroplasty.

BACKGROUND: Visceral obesity, a strong indicator of chronic inflammation and impaired metabolic health, has been shown to be associated with poor postoperative outcomes and complications. This study aimed to evaluate the relationship between visceral fat area (VFA) and periprosthetic joint infection (PJI) in total joint arthroplasty (TJA) patients. METHODS: A retrospective study of 484 patients who had undergone a total hip or knee arthroplasty was performed. All patients had a computed tomography scan of the abdomen/pelvis within two years of their TJA. Body composition data (ie, VFA, subcutaneous fat area, and skeletal muscle area) were calculated at the Lumbar-3 vertebral level via two fully automated and externally validated machine learning algorithms. A multivariable logistic model was created to determine the relationship between VFA and PJI, while accounting for other PJI risk factors. Of the 484 patients, 31 (6.4%) had a PJI complication. RESULTS: The rate of PJI among patients with VFA in the top quartile (> 264.1 cm2) versus bottom quartile (< 82.6 cm2) was 5.6% versus 10.6% and 18.8% versus 2.7% in the total hip arthroplasty and total knee arthroplasty cohorts, respectively. In the multivariate model, total knee arthroplasty patients with a VFA in the top quartile had a 30.5 times greater risk of PJI than those in the bottom quartile of VFA (P = .0154). CONCLUSION: VFA may have a strong association with PJI in TJA patients. Using a standardized imaging modality like computed tomography scans to calculate VFA can be a valuable tool for surgeons when assessing risk of PJI.

Core arbuscular mycorrhizal fungi are predicted by their high abundance-occupancy relationship while host-specific taxa are rare and geographically structured.

Habitat restoration may depend on the recovery of plant microbial symbionts such as arbuscular mycorrhizal (AM) fungi, but this requires a better understanding of the rules that govern their community assembly. We examined the interactions of soil and host-associated AM fungal communities between remnant and restored patches of subtropical montane forests. While AM fungal richness did not differ between habitat types, community membership did and was influenced by geography, habitat and host. These differences were largely driven by rare host-specific AM fungi that displayed near-complete turnover between forest types, while core AM fungal taxa were highly abundant and ubiquitous. The bipartite networks in the remnant forest were more specialized and hosts more specific than in the restored forest. Host-associated AM fungal communities nested within soil communities in both habitats, but only significantly so in the restored forest. Our results provide evidence that restored and remnant forests harbour the same core fungal symbionts, while rare host-specific taxa differ, and that geography, host identity and taxonomic resolution strongly affect the observed distribution patterns of these fungi. We suggest that host-specific interactions with AM fungi, as well as spatial processes, should be explicitly considered to effectively re-establish target host and symbiont communities.

Traits and tradeoffs among non-native ectomycorrhizal fungal symbionts affect pine seedling establishment in a Hawaiian coinvasion landscape.

Pine invasions lead to losses of native biodiversity and ecosystem function, but pine invasion success is often linked to coinvading non-native ectomycorrhizal (EM) fungi. How the community composition, traits, and distributions of these fungi vary over the landscape and how this affects pine success is understudied. A greenhouse bioassay experiment was performed to test the effects of changes in EM fungal community structure from a pine plantation, to an invasion front to currently pine-free areas on percent root colonization and seedling biomass. Soils were also analysed by qPCR to determine changes in inoculum and spore density over distance for a common coinvading EM fungus, Suillus pungens. Percent colonization increased with distance from the plantation, which corresponded with an increase in seedling biomass and stark changes in EM fungal community membership where Suillus spp. dominated currently pine-free areas. However, there was a negative relationship between S. pungens inoculum potential versus root colonization over distance. We conclude that the success of pine invasions is facilitated by specific traits of Suillus spp., but that the success of Suillus is contingent on a lack of competition with other ectomycorrhizal fungi.

Often Overlooked Modifiable Risk Factors Before Total Joint Replacement.

Total joint arthroplasty of the hip and knee are common procedures that effectively manage end-stage arthritis of the hip and knee joint by restoring function and mobility. As total joint arthroplasty transitions from fee-for-service to bundled payments, there is increasing pressure to reduce costs while improving outcomes. Therefore, it is important to understand modifiable risk factors and how to optimize patients using a patient-centered approach before total joint arthroplasty.

Are Narrative Letters of Recommendation for Medical Students Interpreted as Intended by Orthopaedic Surgery Residency Programs?

BACKGROUND: Narrative letters of recommendation are an important component of the residency application process. However, because narrative letters of recommendation are almost always positive, it is unclear whether those reviewing the letters understand the writer's intended strength of support for a given applicant. QUESTIONS/PURPOSES: (1) Is the perception of letter readers for narrative letters of recommendation consistent with the intention of the letter's author? (2) Is there inter-reviewer consistency in selection committee members' perceptions of the narrative letters of recommendation? METHODS: Letter writers who wrote two or more narrative letters of recommendation for applicants to one university-based orthopaedic residency program for the 2014 to 2015 application cycle were sent a survey linked to a specific letter of recommendation they authored to assess the intended meaning regarding the strength of an applicant. A total of 247 unstructured letters of recommendation and accompanying surveys were sent to their authors, and 157 surveys were returned and form the basis of this study (response percentage 64%). The seven core members of the admissions committee (of 22 total reviewers) at a university-based residency program were sent a similar survey regarding their perception of the letter. To answer our research question about whether letter readers' perceptions about a candidate were consistent with the letter writer's intention, we used kappa values to determine agreement for survey questions involving discrete variables and Spearman correlation coefficients (SCCs) to determine agreement for survey questions involving continuous variables. To answer our research question regarding inter-reviewer consistency among the seven faculty members, we compared the letter readers' responses to each survey question using intraclass correlation coefficients (ICCs). RESULTS: There was a negligible to moderate correlation between the intended and perceived strength of the letters (SCC 0.26 to 0.57), with only one of seven letter readers scoring in the moderate correlation category. When stratifying the applicants into thirds, there was only slight agreement (kappa 0.07 to 0.19) between the writers and reviewers. There were similarly low kappa values for agreement about how the writers and readers felt regarding the candidate matching into their program (kappa 0.14 to 0.30). The ICC for each question among the seven faculty reviewers ranged from poor to moderate (ICC 0.42 to 0.52). CONCLUSION: Our results demonstrate that the reader's perception of narrative letters of recommendation did not correlate well with the letter writer's intended meaning and was not consistent between letter readers at a single university-based urban orthopaedic surgery residency program. CLINICAL RELEVANCE: Given the low correlation between the intended strength of the letter writers and the perceived strength of those letters, we believe that other options such as a slider bar or agreed-upon wording as is used in many dean's letters may be helpful.

Trait-based aerial dispersal of arbuscular mycorrhizal fungi.

Dispersal is a key process driving local-scale community assembly and global-scale biogeography of plant symbiotic arbuscular mycorrhizal (AM) fungal communities. A trait-based approach could improve predictions regarding how AM fungal aerial dispersal varies by species. We conducted month-long collections of aerial AM fungi for 12 consecutive months in an urban mesic environment at heights of 20 m. We measured morphological functional traits of collected spores and assessed aerial AM fungal community structure both morphologically and with high-throughput sequencing. Large numbers of AM fungal spores were present in the air over the course of one year and these spores exhibited traits that facilitate aerial dispersal. Measured aerial spores were smaller than average for Glomeromycotinan fungi. Trait-based predictions indicate that nearly 1/3 of described species from diverse genera demonstrate the potential for aerial dispersal. Diversity of aerial AM fungi was relatively high (20 spore species and 17 virtual taxa) and both spore abundance and community structure shifted temporally. The prevalence of aerial dispersal in AM fungi is perhaps greater than previously indicated and a hypothesized model of AM fungal aerial dispersal mechanisms is presented. Anthropogenic soil impacts may liberate AM fungal propagules initiating the dispersal of ruderal species.

Three decades post-reforestation has not led to the reassembly of arbuscular mycorrhizal fungal communities associated with remnant primary forests.

The negative effects of deforestation can potentially be ameliorated through ecological restoration. However, reforestation alone may not reassemble the same ecological communities or functions as primary forests. In part, this failure may be owed to forest ecosystems inherently involving complex interactions among guilds of organisms. Plants, which structure forest food webs, rely on intimate associations with symbiotic microbes such as root-inhabiting mycorrhizal fungi. Here, we leverage a large-scale reforestation project on Hawai'i Island underway for over three decades to assess whether arbuscular mycorrhizal (AM) fungal communities have concurrently been restored. The reference ecosystem for this restoration project is a remnant montane native Hawaiian forest that provides critical habitat for endangered birds. We sampled soils from 12 plots within remnant and restored forest patches and characterized AM fungal communities using high-throughput amplicon sequencing. While some AM fungal community metrics were comparable between remnant and restored forest (e.g. species richness), other key characteristics were not. Specifically, community membership and the identity of AM fungal keystone species differed between the two habitat types, as well as the primary environmental factors influencing community composition. Remnant forest AM fungal communities were strongly associated with soil chemical properties, especially pH, while restored forest communities were influenced by the spatial proximity to remnant forests. We posit that combined, these differences in soil AM fungal communities could be negatively affecting the recruitment of native plant hosts and that future restoration efforts should consider plant-microbe interactions as an important facet of forest health.

Effect of various durations of smoking cessation on postoperative outcomes: A retrospective cohort analysis.

BACKGROUND: Preoperative smoking cessation is commonly advised in an effort to improve postoperative outcomes. However, it remains unclear for how long smoking cessation is necessary, and even whether a brief preoperative period of abstinence is helpful and well tolerated. OBJECTIVE: We evaluated associations between various periods of preoperative smoking cessation and major morbidity and death. DESIGN: Retrospective cohort analysis. SETTING: Adults who had noncardiac surgery at the Cleveland Clinic Main Campus between May 2007 and December 2013. PATIENTS: A total of 37 511 patients whose smoking history was identified from a preoperative Health Quest questionnaire. Of these patients, 26 269 (70%) were former smokers and 11 242 (30%) were current smokers. Of the current smokers, 9482 (84%) were propensity matched with 9482 former smokers (36%). We excluded patients with American Society of Anesthesiologists' physical status exceeding four, patients who did not have general anaesthesia, and patients with missing outcomes and/or covariables. When multiple procedures were performed within the study period, only the first operation for each patient was included in the analysis. MAIN OUTCOME MEASURES: The relationship between smoking cessation and in-hospital morbidity/mortality. RESULTS: The incidence of the primary composite of in-hospital morbidity/mortality was 6.9% (656/9482) for all former smokers; the incidence was 7.8% (152/1951) for patients who stopped smoking less than 1 year before surgery, 6.3% (118/1977) for 1 to 5 years, 7.2% (115/1596) for 5 to 10 years and 6.9% (271/3457) for more than 10 years. CONCLUSION: Smoking cessation was associated with reduced in-hospital morbidity and mortality which was independent of cessation interval.

Phylogenetic structure of arbuscular mycorrhizal fungal communities along an elevation gradient.

Despite the importance of arbuscular mycorrhizal (AM) fungi within terrestrial ecosystems, we know little about how natural AM fungal communities are structured. To date, the majority of studies examining AM fungal community diversity have focused on single habitats with similar environmental conditions, with relatively few studies having assessed the diversity of AM fungi over large-scale environmental gradients. In this study, we characterized AM fungal communities in the soil along a high-elevation gradient in the North American Rocky Mountains. We focused on phylogenetic patterns of AM fungal communities to gain insight into how AM fungal communities are naturally assembled. We found that alpine AM fungal communities had lower phylogenetic diversity relative to lower elevation communities, as well as being more heterogeneous in composition than either treeline or subalpine communities. AM fungal communities were phylogenetically clustered at all elevations sampled, suggesting that environmental filtering, either selection by host plants or fungal niches, is the primary ecological process structuring communities along the gradient.

Navigating the labyrinth: a guide to sequence-based, community ecology of arbuscular mycorrhizal fungi.

Data generated from next generation sequencing (NGS) will soon comprise the majority of information about arbuscular mycorrhizal fungal (AMF) communities. Although these approaches give deeper insight, analysing NGS data involves decisions that can significantly affect results and conclusions. This is particularly true for AMF community studies, because much remains to be known about their basic biology and genetics. During a workshop in 2013, representatives from seven research groups using NGS for AMF community ecology gathered to discuss common challenges and directions for future research. Our goal was to improve the quality and accessibility of NGS data for the AMF research community. Discussions spanned sampling design, sample preservation, sequencing, bioinformatics and data archiving. With concrete examples we demonstrated how different approaches can significantly alter analysis outcomes. Failure to consider the consequences of these decisions may compound bias introduced at each step along the workflow. The products of these discussions have been summarized in this paper in order to serve as a guide for any researcher undertaking NGS sequencing of AMF communities.

Incidence of intraoperative hypersensitivity reactions: a registry analysis: a registry analysis.

BACKGROUND: Previously reported incidences for intraoperative hypersensitivity reactions vary more than 15-fold. The goal was to determine the incidence of intraoperative hypersensitivity events at a U.S. surgical center. METHODS: With institutional review board (Cleveland, Ohio) approval and waiver of written/informed consent, the anesthesia records of adult patients undergoing noncardiac surgery from 2005 to 2011 at the Cleveland Clinic were queried using a novel electronic search protocol developed to identify potential hypersensitivity reactions: cardiovascular collapse defined as systolic arterial blood pressure less than 50 mmHg; administration of epinephrine; administration of diphenhydramine; physician comments in the anesthesia record suggestive of hypersensitivity reactions; laboratory tests for histamine, tryptase, or immunoglobulin-E within 24 h of surgery; and International Classification of Diseases, Ninth Revision, codes suggestive of hypersensitivity reactions. Each electronically identified candidate chart was evaluated by an adjudication committee. Hypersensitivity reactions were graded on a 5-point severity scale. From these data, the authors determined the proportion of operations having adjudicated hypersensitivity reactions, and calculated the 95% exact binomial CI. RESULTS: Among 178,746 records, 4,008 charts were identified by the search strategies. After adjudication, 264 hypersensitivity cases were identified. The overall incidence of hypersensitivity reactions was 1:677 surgeries, corresponding to 15 (95% CI, 13 to 17) cases per 10,000 operations. The incidence of severe hypersensitivity reactions (grades 3 to 5) was 1:4,583, corresponding to 2 (95% CI, 2 to 3) cases per 10,000 operations. CONCLUSIONS: The incidence of severe hypersensitivity reactions was similar to previous reports. However, the overall incidence of hypersensitivity reactions was much greater than reported elsewhere, possibly because of a comprehensive search strategy.

Relationship between chronic intermittent hypoxia and intraoperative mean arterial pressure in obstructive sleep apnea patients having laparoscopic bariatric surgery.

BACKGROUND: Recurrent nocturnal hypoxemia in obstructive sleep apnea enhances sympathetic function, decreases baroreceptor sensitivity, and weakens peripheral vascular responses to adrenergic signals. The authors hypothesized that the percentage of total sleep time spent at oxyhemoglobin saturation (SaO2) less than 90% and minimum nocturnal SaO2 on preoperative polysomnography are associated with decreased intraoperative mean arterial pressure. METHODS: The authors examined the records of all patients who had laparoscopic bariatric surgery at Cleveland Clinic between 2005 and 2009 and an available polysomnography study. The authors assessed the relationships between the percentage of total sleep time spent at SaO2 less than 90% and minimum nocturnal SaO2, and the time-weighted average of mean arterial pressure. The authors used multivariable regression models to adjust for prespecified clinical confounders. RESULTS: Two hundred eighty-one patients were included in the analysis. The average change in the time-weighted average of mean arterial pressure was -0.02 (97.5% CI, -0.08, 0.04) mmHg for each 1% absolute increase in the percentage of sleep time spent at SaO2 less than 90% (P = 0.50). The average change was -0.13 (97.5% CI, -0.27, 0.01) mmHg, for each 1% absolute decrease in the minimum SaO2 (P = 0.04 > significance criterion of 0.025, Bonferroni correction). An unplanned analysis estimated 1% absolute decrease in minimum SaO2 was associated with -0.22 (98.75% CI, -0.39, -0.04) mmHg, change in mean arterial pressure (P = 0.002) in the time period between endotracheal intubation and trocar insertion. CONCLUSION: Recurrent nocturnal hypoxemia in obstructive sleep apnea is not a risk marker for intraoperative hypotension.

Diagnostic Test Performances for Identifying Periprosthetic Joint Infection in Hip Hemiarthroplasty.

INTRODUCTION: Periprosthetic joint infection (PJI) is a devastating complication of hip hemiarthroplasty (HHA) that is not well-represented in the literature. Therefore, this study aimed to evaluate diagnostic markers for identifying PJI in patients after HHA and compare them with the most recent 2018 International Consensus Meeting on Musculoskeletal Infection criteria. METHODS: A total of 98 patients (64 PJIs, 65.3%) were analyzed. Patients were identified by relevant Current Procedural Terminology and International Classification of Diseases-9/10 codes from 2000 to 2021 across a single healthcare system. Preoperative or intraoperative synovial fluid nucleated cell (NC) count, synovial polymorphonuclear (PMN) percentage, serum erythrocyte sedimentation rate (ESR), serum C-reactive protein (CRP), and serum white blood cell count were compared with Student t -test between aseptic and septic cohorts. Diagnostic utility and laboratory cutoff values were determined using receiver-operating characteristic curves and Youden index, respectively. RESULTS: Mean values were significantly higher in the septic cohort for synovial NC count (120,992.2 versus 1,498.0 cells/µL, P < 0.001), synovial PMN percentage (91.3% versus 56.2%, P < 0.001), serum ESR (75.6 versus 36.3 mm/hr, P < 0.001), serum CRP (20.2 versus 125.8 mg/L, P < 0.001), and serum white blood cell count (8.5 versus 11.5 cells/µL, P < 0.001). Synovial NC count, synovial PMN percentage, and serum CRP had excellent PJI discriminatory ability with an area under the curve of 0.99, 0.90, and 0.93, respectively. Optimal cutoffs were 2,700 cells/µL for synovial NC count (100% sensitivity and 94% specificity), 81.0% for synovial PMN percentage (96% sensitivity and 89% specificity), 52.0 mm/hr for serum ESR (75% sensitivity and 80% specificity), and 40.0 mg/L for serum CRP (85% sensitivity and 92% specificity). CONCLUSION: Our findings support the continued use of routine serum and synovial fluid tests for diagnosing PJI in HHA patients. Optimal cutoff values for both synovial fluid biomarkers were very close in alignment with the 2018 International Consensus Meeting criteria. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

The accuracy of a disposable noninvasive core thermometer.

PURPOSE: Perioperative hypothermia is still a common occurrence, and it can be difficult to measure a patient's core temperature accurately, especially during regional anesthesia, with placement of a laryngeal mask airway device, or postoperatively. We evaluated a new disposable double-sensor thermometer and compared the resulting temperatures with those of a distal esophageal thermometer and a bladder thermometer in patients undergoing general and regional anesthesia, respectively. Furthermore, we compared the accuracy of the thermometer between regional and general anesthesia, since forehead microcirculation might differ between the two types of anesthesia. METHODS: We assessed core temperature in 36 general anesthesia patients and 20 patients having regional anesthesia for orthopedic surgery. The temperatures obtained using the double-sensor thermometer were compared with those obtained with the distal esophageal thermometer in the general anesthesia population and those obtained with the bladder thermometer in regional anesthesia patients. RESULTS: In our general anesthesia patients, 90% (95% confidence interval [CI] 85 to 95) of all double-sensor values were within 0.5°C of esophageal temperatures. The average difference (bias) between the esophageal and double-sensor temperatures was -0.01°C. In patients undergoing regional anesthesia 89% (95% CI 80 to 97) of all double-sensor values were within 0.5°C of bladder temperatures. The average difference (bias) between the bladder and double-sensor temperatures was -0.13°C, limits of agreement were -0.65 to 0.40°C. CONCLUSIONS: In a perioperative patient population undergoing general or regional anesthesia, the accuracy of the noninvasive disposable double-sensor thermometer is comparable with that of the distal esophageal and bladder thermometers in routine clinical practice. Furthermore, the sensor performed comparably in patients undergoing regional and general anesthesia.

Sarcopenia is an independent risk factor for failure to achieve the 1-year MCID of the KOOS, JR and PROMIS PF-SF10a after TKA.

BACKGROUND: Sarcopenia, which is a progressive and multifactorial condition of decreased muscle strength, has been identified as an independent predictor for falls, revision, infection, and readmissions following total knee arthroplasty (TKA), but its association to patient reported outcomes (PROMs) is less studied. The aim of this study is to determine if sarcopenia and other measures of body composition are correlated with ability to achieve the 1-year minimal clinically important difference (MCID) of the KOOS JR and PROMIS-PF-SF10a following primary TKA. METHODS: A multicenter retrospective case-control study was performed. Inclusion criteria consisted of patients over the age of 18 undergoing primary TKA, body composition metrics determined by computed tomography (CT), and available pre- and post-operative PROM scores. Predictors of achievement of the 1-year MCID of the KOOS JR and PROMIS PF-SF-10a were determined through a multivariate linear regression. RESULTS: 140 primary TKAs met inclusion criteria. 74 (52.85%) patients achieved the 1-year KOOS, JR MCID and 108 (77.41%) patients achieved the 1-year MCID for the PROMIS PF-SF10a. Sarcopenia was independently associated with decreased odds of achieving the MCID of both the KOOS, JR (OR 0.31, 95%CI 0.10-0.97, p = 0.04) and the PROMIS-PF-SF10a (OR 0.32, 95%CI 0.12-0.85, p = 0.02) CONCLUSIONS: In our study, sarcopenia was independently associated with increased odds of failure to achieve the 1-year MCID of the KOOS, JR and PROMIS PF-SF10a after TKA. Early identification of sarcopenic patients may be beneficial for arthroplasty surgeons so that targeted nutritional counseling and exercises can be recommended prior to TKA.

Total Joint Arthroplasty in Homeless Patients at an Urban Safety Net Hospital.

INTRODUCTION: Homelessness is a key social determinant of health, and the patient population has grown to over 580,000. Total joint arthroplasty (TJA) is an effective treatment of symptomatic end-stage osteoarthritis of the hip and knee and has been shown to improve health-related quality of life in the general population. However, the literature on the outcomes of TJA among homeless patients is limited. METHODS: We retrospectively reviewed 442 patients who underwent primary, unilateral TJA between June 1, 2016, and August 31, 2017, at an urban, tertiary, academic safety net hospital. Based on self-reported living status, we classified 28 homeless patients and 414 control nonhomeless patients. Fisher exact tests, Student t-tests, and multivariate logistic regression were used to compare the demographics, preoperative conditions, and surgical outcomes between the two groups. RESULTS: The homeless group were younger, more often male, and smokers; had alcohol use disorder; and used illicit drugs. After controlling for age, sex, and preoperative medical and social conditions, homeless patients were 15.83 times more likely to have an emergency department visit (adjusted odds ratio, 15.83; 95% confidence interval, 5.05 to 49.59; P < 0.0001) within 90 days but had similar rates of readmission (P = 0.25), revision surgery (P = 0.38), and prosthetic joint infection (P = 0.25) when compared with nonhomeless patients. DISCUSSION: Although homeless patients did not have higher rates of readmission or revision surgery, homelessness still presents unique challenges for the TJA patients and providers. With careful preoperative optimization and collaborative support, however, the benefits of TJA may outweigh the risk of poor outcomes for these patients.

What are mycorrhizal traits?

Traits are inherent properties of organisms, but how are they defined for organismal networks such as mycorrhizal symbioses? Mycorrhizal symbioses are complex and diverse belowground symbioses between plants and fungi that have proved challenging to fit into a unified and coherent trait framework. We propose an inclusive mycorrhizal trait framework that classifies traits as morphological, physiological, and phenological features that have functional implications for the symbiosis. We further classify mycorrhizal traits by location - plant, fungus, or the symbiosis - which highlights new questions in trait-based mycorrhizal ecology designed to charge and challenge the scientific community. This new framework is an opportunity for researchers to interrogate their data to identify novel insights and gaps in our understanding of mycorrhizal symbioses.

A randomized comparison of intraoperative PerfecTemp and forced-air warming during open abdominal surgery.

BACKGROUND: The PerfecTemp is an underbody resistive warming system that combines servocontrolled underbody warming with viscoelastic foam pressure relief. Clinical efficacy of the system has yet to be formally evaluated. We therefore tested the hypothesis that intraoperative distal esophageal (core) temperatures with the PerfecTemp (underbody resistive) warming system are noninferior to upper-body forced-air warming in patients undergoing major open abdominal surgery under general anesthesia. METHODS: Adults scheduled for elective major open abdominal surgery (liver, pancreas, gynecological, and colorectal surgery) under general anesthesia were enrolled at 2 centers. Patients were randomly assigned to underbody resistive or forced-air warming. Resistive heating started when patients were transferred to the operating room table; forced-air warming started after patients were draped. The primary outcome was noninferiority of intraoperative time-weighted average core temperature, adjusted for baseline characteristics and using a buffer of 0.5°C. RESULTS: Thirty-six patients were randomly assigned to underbody resistive heating and 34 to forced-air warming. Baseline and surgical characteristics were generally similar. We had sufficient evidence (P=0.018) to conclude that underbody resistive warming is not worse than (i.e., noninferior to) upper-body forced-air warming in the time-weighted average intraoperative temperature, with a mean difference of -0.12°C [95% confidence interval (CI) -0.37 to 0.14]. Core temperatures at the end of surgery averaged 36.3°C [95% CI 36 to 36.5] in the resistive warming patients and 36.6°C [95% CI 36.4 to 36.8] in those assigned to forced-air warming for a mean difference of -0.34°C [95% CI -0.69 to 0.01]. CONCLUSIONS: Mean intraoperative time-weighted average core temperatures were no different, and significantly noninferior, with underbody resistive heating in comparison with upper-body forced-air warming. Underbody resistive heating may be an alternative to forced-air warming.

Plant-microbe specificity varies as a function of elevation.

Specialized associations between interacting species fundamentally determine the diversity and distribution of both partners. How the specialization of guilds of organisms varies along environmental gradients underpins popular theories of biogeography and macroecology, whereas the degree of specialization of a species is typically considered fixed. However, the extent to which environmental context impacts specialization dynamics is seldom examined empirically. In this study, we examine how specialization within a bipartite network consisting of three co-occurring plant species and their foliar fungal endophyte symbionts changes along a 1000-meter elevation gradient where host species were held constant. The gradient, along the slope of Mauna Loa shield volcano, represents almost the entire elevational range of two of the three plants. Network and plant specialization values displayed a parabolic relationship with elevation, and were highest at middle elevations, whereas bipartite associations were least specific at low and high elevations. Shannon's diversity of fungal endophytes correlated negatively with specificity, and was highest at the ends of the transects. Although plant host was a strong determinant of fungal community composition within sites, fungal species turnover was high among sites. There was no evidence of spatial or elevational patterning in fungal community compositon. Our work demonstrates that specificity can be a plastic trait, which is influenced by the environment and centrality of the host within its natural range.

Incidence of insufficient intraoperative neuromuscular paralysis. A retrospective registry analysis.

STUDY OBJECTIVE: Muscular tone that inhibits anesthetic or surgical care characterizes insufficient neuromuscular block. The incidence of insufficient neuromuscular block is unknown, therefore we developed novel electronic search strategies to identify occurrences of insufficient neuromuscular block. Our primary goal was to determine the incidence of intraoperative insufficient neuromuscular block in abdominal and neurovascular surgery. Our secondary goal was to assess factors independently associated with insufficient block. DESIGN: Retrospective cohort. SETTING: Operating rooms in a tertiary care center. PATIENTS: Adults having abdominal, laparoscopic, and interventional neurovascular procedures under general anesthesia with endotracheal intubation between April 2005 and February 2013. MEASUREMENTS: An expert panel of anesthesiologists used a Delphi process to develop criteria to identify insufficient intraoperative neuromuscular block. 10 final criteria were agreed upon and used to determine the incidence of insufficient neuromuscular block. MAIN RESULTS: 48,315 surgeries met our inclusion requirements. Intraoperative insufficient neuromuscular block was identified in 13,538 cases, representing 28% (95% CI: 27.6%, 28.4%) of the operations. Younger age, male sex, type of surgery, longer duration of surgery, pre-existing conditions, and use of volatile anesthetics were independently associated with insufficient block after Bonferroni correction. CONCLUSION: Our results suggest that episodes of insufficient block occur in over a quarter of operations that are generally thought to require muscle relaxation. Without neuromuscular monitoring, it is difficult to separate inadequate anesthesia from inadequate neuromuscular block, and both presumably contributed in many cases.