Development and evaluation of a computerized algorithm for the interpretation of pulmonary function tests.

Pulmonary function tests (PFTs) are usually interpreted by clinicians using rule-based strategies and pattern recognition. The interpretation, however, has variabilities due to patient and interpreter errors. Most PFTs have recognizable patterns that can be categorized into specific physiological defects. In this study, we developed a computerized algorithm using the python package (pdfplumber) and validated against clinicians' interpretation. We downloaded PFT reports in the electronic medical record system that were in PDF format. We digitized the flow volume loop (FVL) and extracted numeric values from the reports. The algorithm used FEV1/FVC<0.7 for obstruction, TLC<80%pred for restriction and <80% or >120%pred for abnormal DLCO. The algorithm also used a small airway disease index (SADI) to quantify late expiratory flattening of the FVL to assess small airway dysfunction. We devised keywords for the python Natural Language Processing (NLP) package (spaCy) to identify obstruction, restriction, abnormal DLCO and small airway dysfunction in the reports. The algorithm was compared to clinicians' interpretation in 6,889 PFTs done between March 1st, 2018, and September 30th, 2020. The agreement rates (Cohen's kappa) for obstruction, restriction and abnormal DLCO were 94.4% (0.868), 99.0% (0.979) and 87.9% (0.750) respectively. In 4,711 PFTs with FEV1/FVC≥0.7, the algorithm identified 190 tests with SADI < lower limit of normal (LLN), suggesting small airway dysfunction. Of these, the clinicians (67.9%) also flagged 129 tests. When SADI was ≥ LLN, no clinician's reports indicated small airway dysfunction. Our results showed the computerized algorithm agreed with clinicians' interpretation in approximately 90% of the tests and provided a sensitive objective measure for assessing small airway dysfunction. The algorithm can improve efficiency and consistency and decrease human errors in PFT interpretation. The computerized algorithm works directly on PFT reports in PDF format and can be adapted to incorporate a different interpretation strategy and platform.

Cocaine use in trauma: the vices-paradox revisited.

BACKGROUND: The "vices-paradox" describes the paradoxical association between illicit substance use and decreased mortality risk in trauma patients. Cocaine's vasoconstrictive effects may decrease hemorrhage but also increase the risk of thromboembolic complications. To clarify the effects of cocaine use on trauma patients, we compared the risk of mortality and thromboembolic complications in patients screening positive for cocaine with those screening negative. METHODS: We searched the Trauma Quality Improvement Program database to identify patients 18 years and over who had presented with a drug and alcohol screen on admission between 2017 and 2019. After excluding all patients who had tested positive for alcohol and substances other than cocaine, we then compared the clinical outcomes of patients who were positive and negative for cocaine use. RESULTS: Of the 312,553 patients identified, 11,942 (3.82%) had tested positive for cocaine. Cocaine users were significantly more likely to present with stab (8.0% vs 3.1%) or gunshot wounds (8.0% vs 3.0%) but had lower rates of mortality (3.6% vs 4.7%), myocardial infarction (0.1% vs 0.2%,) and cerebrovascular accident (0.3% vs 0.4%,). After controlling for covariates, the risk of death, myocardial infarction, and cerebrovascular accident did not significantly differ between cocaine and non-cocaine users. CONCLUSION: Trauma patients positive for cocaine have similar risks of death and thromboembolic complications and so have a similar prognosis to patients negative for all drugs or alcohol, indicating that the "vices-paradox" does not apply to cocaine use. However, these patients more commonly present after penetrating trauma, suggesting cocaine use in hazardous environments.

The Effects of Automatic Inspiratory Rise Time and Flow Termination on Operation of Closed-Loop Ventilation.

BACKGROUND: Adaptive ventilation mode (AVM) is a automated mode of mechanical ventilation. AVM is comprable to adaptive support ventilation (ASV). Both recommend a tidal volume (VT) and breathing frequency (f) combination based on lung mechanics, but AVM also automatically adjusts rise time and flow termination of pressure support breaths. How these added features of AVM affect VT and f recommendations compared to ASV is not clear. The present study compared these 2 modes in a test lung with obstructive and restrictive mechanics. METHODS: The experiment was performed in a simulated lung model in which the compliance (C) and resistance (R) could be altered independently. The ventilatory parameters at different minute volumes (MinVol%) in AVM or ASV mode were recorded. RESULTS: When MinVol% was set at 100%, AVM provided a similar VT and f combination compared to ASV with decreasing compliance or increasing resistance. However, when MinVol% was increased to 250% simulating hyperventilation, for the severely obstructive lung (C60, R70) model, AVM provided a significantly higher f (26 ± 0.6 breaths/min vs 7.00 ± 0 breaths/min in ASV) and lower VT (240 ± 80 mL vs 491 ± 131 mL in ASV). CONCLUSIONS: The addition of automatic control of rise time and flow termination functions did not affect recommended ventilator settings in AVM in the noncompliant or obstructive lung when minute ventilation (V̇E) was low. At higher V̇E, AVM compared to ASV recommended a ventilatory strategy with lower VT and higher f. These results need to be validated in patients.

[The relationship between oral microbiota and taste]. / De relatie tussen mondmicrobiota en smaak.

Disruption of the perception of taste can have severe consequences on general health. Although evidence suggests that the oral microbiota plays a role in taste perception, little is known about this possible influence. In this scoping review, the influence of oral microbiota on taste perception was studied. Current scientific literature is heterogeneous in study methods and study populations, which impedes comparison of results. Although the findings of this review provide insufficient evidence to confirm the influence of oral microbiota on taste perception, some results show a relationship between taste perception and specific microorganisms. Several factors play a role in taste perception, including tongue coating, use of medication, advanced age, and decreased salivary flow rate, and when these factors are present, it is important to be alert to possible changes in taste. Large-scale studies, in which the multifactorial etiology of taste perception is addressed, are needed to clarify the role of the oral microbiota on taste perception.

Development and Evaluation of a Small Airway Disease Index Derived From Modeling the Late-Expiratory Flattening of the Flow-Volume Loop.

Excessive decrease in the flow of the late expiratory portion of a flow volume loop (FVL) or "flattening", reflects small airway dysfunction. The assessment of the flattening is currently determined by visual inspection by the pulmonary function test (PFT) interpreters and is highly variable. In this study, we developed an objective measure to quantify the flattening. We downloaded 172 PFT reports in PDF format from the electronic medical records and digitized and extracted the expiratory portion of the FVL. We located point A (the point of the peak expiratory flow), point B (the point corresponding to 75% of the expiratory vital capacity), and point C (the end of the expiratory portion of the FVL intersecting with the x-axis). We did a linear fitting to the A-B segment and the B-C segment. We calculated: 1) the AB-BC angle (∠ABC), 2) BC-x-axis angle (∠BCX), and 3) the log ratio of the BC slope over the vertical distance between point A and x-axis [log (BC/A-x)]. We asked an expert pulmonologist to assess the FVLs and separated the 172 PFTs into the flattening and the non-flattening groups. We defined the cutoff value as the mean minus one standard deviation using data from the non-flattening group. ∠ABC had the best concordance rate of 80.2% with a cutoff value of 149.7°. We then asked eight pulmonologists to evaluate the flattening with and without ∠ABC in another 168 PFTs. The Fleiss' kappa was 0.320 (lower and upper confidence intervals [CIs]: 0.293 and 0.348 respectively) without ∠ABC and increased to 0.522 (lower and upper CIs: 0.494 and 0.550) with ∠ABC. There were 147 CT scans performed within 6 months of the 172 PFTs. Twenty-six of 55 PFTs (47.3%) with ∠ABC <149.7° had CT scans showing small airway disease patterns while 44 of 92 PFTs (47.8%) with ∠ABC ≥149.7° had no CT evidence of small airway disease. We concluded that ∠ABC improved the inter-rater agreement on the presence of the late expiratory flattening in FVL. It could be a useful addition to the assessment of small airway disease in the PFT interpretation algorithm and reporting.

Comparative Outcomes for Trauma Patients in Prison and the General Population.

BACKGROUND: Prisoners are a vulnerable population, and there are few contemporary studies that consider trauma patient outcomes within the prisoner population. Therefore, we sought to provide a descriptive analysis of prisoners involved in trauma and evaluate whether a healthcare disparity exists. We hypothesized that prisoners and non-prisoners have a similar risk of mortality and in-hospital complications after trauma. METHODS: The Trauma Quality Improvement Program (2015-2016) was queried for trauma patients based upon location inside or outside of prison at the time of injury. A multivariable logistic regression analysis was performed to compare these groups for risk of mortality-the primary outcome. RESULTS: From 593,818 trauma patients, 1115 were located in prison. Compared to non-prisoners, prisoner trauma patients had no significant difference in mortality (5.1 vs 6.0%, P = .204). However, after adjusting for covariates, prisoners had a shorter length of stay (LOS) (mean days, 6.3 vs 7.8, P < .001), shorter intensive care unit (ICU) LOS (mean days, 5.44 vs 5.89, P = .004), and fewer complications, including lower rates of drug/alcohol withdrawal (.4% vs 1.1%, P = .030), pneumonia (.5 vs 1.6%, P = .004), and urinary tract infections (.0 vs 1.1%, P < .001). Upon performing a multivariable logistic regression model, prisoner trauma patients had a similar associated risk of mortality compared to non-prisoners (OR 1.61, CI .52-4.94, P = .409). DISCUSSION: Our results suggest that prisoner trauma patients at least receive equivalent treatment in terms of mortality and may have better outcomes when considering some complications. Future prospective studies are needed to confirm these results and explore other factors, which impact prisoner patient outcomes.

Application of Machine Learning in Pulmonary Function Assessment Where Are We Now and Where Are We Going?

Analysis of pulmonary function tests (PFTs) is an area where machine learning (ML) may benefit clinicians, researchers, and the patients. PFT measures spirometry, lung volumes, and carbon monoxide diffusion capacity of the lung (DLCO). The results are usually interpreted by the clinicians using discrete numeric data according to published guidelines. PFT interpretations by clinicians, however, are known to have inter-rater variability and the inaccuracy can impact patient care. This variability may be caused by unfamiliarity of the guidelines, lack of training, inadequate understanding of lung physiology, or simply mental lapses. A rules-based automated interpretation system can recapitulate expert's pattern recognition capability and decrease errors. ML can also be used to analyze continuous data or the graphics, including the flow-volume loop, the DLCO and the nitrogen washout curves. These analyses can discover novel physiological biomarkers. In the era of wearables and telehealth, particularly with the COVID-19 pandemic restricting PFTs to be done in the clinical laboratories, ML can also be used to combine mobile spirometry results with an individual's clinical profile to deliver precision medicine. There are, however, hurdles in the development and commercialization of the ML-assisted PFT interpretation programs, including the need for high quality representative data, the existence of different formats for data acquisition and sharing in PFT software by different vendors, and the need for collaboration amongst clinicians, biomedical engineers, and information technologists. Hurdles notwithstanding, the new developments would represent significant advances that could be the future of PFT, the oldest test still in use in clinical medicine.

Using hyperpolarized 129Xe gas-exchange MRI to model the regional airspace, membrane, and capillary contributions to diffusing capacity.

Hyperpolarized 129Xe MRI has emerged as a novel means to evaluate pulmonary function via 3D mapping of ventilation, interstitial barrier uptake, and RBC transfer. However, the physiological interpretation of these measurements has yet to be firmly established. Here, we propose a model that uses the three components of 129Xe gas-exchange MRI to estimate accessible alveolar volume (VA), membrane conductance, and capillary blood volume contributions to DLCO. 129Xe ventilated volume (VV) was related to VA by a scaling factor kV = 1.47 with 95% confidence interval [1.42, 1.52], relative 129Xe barrier uptake (normalized by the healthy reference value) was used to estimate the membrane-specific conductance coefficient kB = 10.6 [8.6, 13.6] mL/min/mmHg/L, whereas normalized RBC transfer was used to calculate the capillary blood volume-specific conductance coefficient kR = 13.6 [11.4, 16.7] mL/min/mmHg/L. In this way, the barrier and RBC transfer per unit volume determined the transfer coefficient KCO, which was then multiplied by image-estimated VA to obtain DLCO. The model was built on a cohort of 41 healthy subjects and 101 patients with pulmonary disorders. The resulting 129Xe-derived DLCO correlated strongly (R2 = 0.75, P < 0.001) with the measured values, a finding that was preserved within each individual disease cohort. The ability to use 129Xe MRI measures of ventilation, barrier uptake, and RBC transfer to estimate each of the underlying constituents of DLCO clarifies the interpretation of these images while enabling their use to monitor these aspects of gas exchange independently and regionally.NEW & NOTEWORTHY The diffusing capacity for carbon monoxide (DLCO) is perhaps one of the most comprehensive physiological measures used in pulmonary medicine. Here, we spatially resolve and estimate its key components-accessible alveolar volume, membrane, and capillary blood volume conductances-using hyperpolarized 129Xe MRI of ventilation, interstitial barrier uptake, and red blood cell transfer. This image-derived DLCO correlates strongly with measured values in 142 subjects with a broad range of pulmonary disorders.

Exposure Assessment Tools for Hypersensitivity Pneumonitis. An Official American Thoracic Society Workshop Report.

This report is based on proceedings from the Exposure Assessment Tools for Hypersensitivity Pneumonitis (HP) Workshop, sponsored by the American Thoracic Society, that took place on May 18, 2019, in Dallas, Texas. The workshop was initiated by members from the Environmental, Occupational, and Population Health and Clinical Problems Assemblies of the American Thoracic Society. Participants included international experts from pulmonary medicine, occupational medicine, radiology, pathology, and exposure science. The meeting objectives were to 1) define currently available tools for exposure assessment in evaluation of HP, 2) describe the evidence base supporting the role for these exposure assessment tools in HP evaluation, 3) identify limitations and barriers to each tool's implementation in clinical practice, 4) determine which exposure assessment tools demonstrate the best performance characteristics and applicability, and 5) identify research needs for improving exposure assessment tools for HP. Specific discussion topics included history-taking and exposure questionnaires, antigen avoidance, environmental assessment, specific inhalational challenge, serum-specific IgG testing, skin testing, lymphocyte proliferation testing, and a multidisciplinary team approach. Priorities for research in this area were identified.

Chronic hypersensitivity pneumonitis in the southeastern United States: an assessment of how clinicians reached the diagnosis.

BACKGROUND: Chronic hypersensitivity pneumonitis (cHP) is a disease caused by exposure to inhaled environmental antigens. Diagnosis of cHP is influenced by the awareness of the disease prevalence, which varies significantly in different regions, and how clinicians utilize relevant clinical information. We conducted a retrospective study to evaluate how clinicians in the Southeast United States, where the climate is humid favoring mold growth, diagnosed cHP using items identified in the international modified Delphi survey of experts, i.e., environmental exposure, CT imaging and lung pathology, METHODS: We searched Duke University Medical Center database for patients over the age of 18 with a diagnosis of cHP (ICD-9 code: 495) between Jan. 1, 2008 to Dec. 31, 2013 using a query tool, Duke Enterprise Data Unified Content Explorer (DEDUCE). RESULTS: Five hundred patients were identified and 261 patients had cHP confirmed in clinic notes by a pulmonologist or an allergist. About half of the patients lived in the Research Triangle area where our medical center is located, giving an estimated prevalence rate of 6.5 per 100,000 persons. An exposure source was mentioned in 69.3% of the patient. The most common exposure sources were environmental molds (43.1%) and birds (26.0%). We used Venn diagram to evaluate how the patients met the three most common cHP diagnostic criteria: evidence of environmental exposures (history or precipitin) (E), chest CT imaging (C) and pathology from lung biopsies (P). Eighteen patients (6.9%) met none of three criteria. Of the remaining 243 patients, 135 patients (55.6%) had one (E 35.0%, C 3.3%, P 17.3%), 81 patients (33.3%) had two (E + C 12.3%, E + P 17.3%, C + P 4.9%), and 27 patients (11.1%) had all three criteria (E + C + P). Overall, 49.4% of patients had pathology from lung biopsy compared to 31.6% with CT scan. CONCLUSIONS: Environmental mold was the most common exposure for cHP in the Southeast United States. Lung pathology was available in more than half of cHP cases in our tertiary care center, perhaps reflecting the complexity of referrals. Differences in exposure sources and referral patterns should be considered in devising future diagnostic pathways or guidelines for cHP.

Metabolomic correlates of aerobic capacity among elderly adults.

BACKGROUND: Aerobic capacity is a powerful predictor of cardiovascular disease and all-cause mortality, and it declines with advancing age. HYPOTHESIS: Since physical activity alters body metabolism, metabolism markers will likely differ between subjects with high vs low aerobic capacities. METHODS: Community-based participants without physician-diagnosed heart disease, stroke or cancer underwent same-day multimodal assessment of cardiovascular function (by echocardiography and magnetic resonance feature tracking of left atrium) and aerobic capacity by peak oxygen uptake (VO2 ) metrics. Associations between VO2 and cardiovascular and metabolomics profiles were studied in adjusted models including standard covariates. RESULTS: We studied 141 participants, of whom 82 (58.2%) had low VO2 , while 59 (41.8%) had high VO2 . Compared to participants with high VO2 , participants with low VO2 had more adverse cardiovascular parameters, such as lower ratio of peak velocity flow in early diastole to peak velocity flow in late diastole by atrial contraction of >0.8 (76% vs 35%, adjusted odd ratio [OR] = 4.1, 95% confidence interval [CI] [1.7-9.5], P = 0.001) and lower left atrial conduit strain (11.3 ± 4.0 vs 15.6 ± 6.1%, adjusted OR = 1.1, 95% CI [1.002-1.3], P = 0.045). High VO2 was associated with lower accumulation of wide-spectrum acyl-carnitines (OR = 0.6, 95% CI [0.4-0.9], P = 0.013), alanine (OR = 0.1, 95% CI [0.01-0.9], P = 0.044) and glutamine /glutamate (OR = 0.1, 95% CI [0.01-0.5], P = 0.007), compared to low VO2. CONCLUSION: Elderly adults with low VO2 have adverse cardiovascular and metabolic parameters compared to their counterparts with high VO2 . Combined cardiac and metabolomics phenotyping may be a promising tool to provide insights into physiological states, useful for tracking future interventions related to physical activity among community cohorts.

What Is the Role of Diagnostic and Therapeutic Sonication in Periprosthetic Joint Infections?

BACKGROUND: Periprosthetic joint infection (PJI) is one of the most dreaded complications in joint replacement surgery. Diagnosis and treatment can be difficult and biofilms are of major concern due to their low susceptibility toward antibiotics. METHODS: This review focuses on the use of sonication as an evolving diagnostic and adjunct treatment modality in the context of PJI. Therapeutic application of sonication is discussed separately for its (i) direct action on bacteria, (ii) synergistic effects with antibiotics, and (iii) effects on release of antibiotics from bone cement. RESULTS: Used as a diagnostic tool, sonication shows promising results with respect to sensitivity and specificity when compared to conventional methods, notably after previous administration of antibiotics. As an adjunct treatment modality, the chemical, physical, and mechanical effects of sonication are primarily driven by cavitation and recognized as the main cause for bactericidal effects but the exact underlying mechanisms have not been identified yet. Sonication alone does not have the ability to completely eradicate biofilms but synergistic effects when used in conjunction with antibiotics have been reported. There is also evidence for enhanced antibiotic release from bone cement. CONCLUSION: Sonication is as an evolving modality in the context of PJIs. As a diagnostic tool, it has not been introduced in routine clinical practice and sonication as a treatment modality in PJIs is still in an experimental stage. Factors such as frequency, pressure, chemical activity, intensity, and exposure time need to be evaluated for optimal application of sonication and may also improve study comparison.

PEEK Implant: A Case Report Illustrating the Benefits for Correcting Craniosynostosis Asymmetry.

BACKGROUND: Unilateral coronal synostosis can cause aesthetically unappealing plagiocephaly, which often requires surgical correction. The techniques utilized for this operation have continued to evolve. Unfortunately, some patients who have fronto-orbital advancement will have residual asymmetry. CASE: We present a case of a 21 year-old female with residual asymmetry who was suffering from facial swelling and refractory trigeminal neuralgia. It was decided to perform an additional surgery with polytheretheketone (PEEK) implant to restore normal symmetry and provide symptomatic relief. CONCLUSION: The ideal fit PEEK implant provided excellent cosmetic results and the operation relieved her symptoms. We provide a detailed discussion on why PEEK implants are great options for these types of cases due to advanced pre-surgical planning technology, ease of placement, and durability over time.

Surgery beyond the visible light spectrum: theoretical and applied methods for localization of the male urethra during transanal total mesorectal excision.

The risk of urethral injury during transanal total mesorectal excision (taTME) is delineated, and potential risk factors for iatrogenic transection are reviewed. A variety of applied and theoretical techniques can be used by surgeons to diminish the risk of injury in males undergoing this operation. Many of the approaches utilize non-optic media and wavelengths beyond the visible light spectrum which can enhance the surgeon's frame of reference. The aim of the present study was to assess the techniques and theoretical approaches to urethral localization during taTME. Future directions in surgical imaging are also discussed, including the use of organic dyes, quantum dots, and carbon nanotubes; collectively, technology that could someday provide surgeons with an ability to identify anatomic structures prone to injury.

Correlation between transition percentage of minute volume (TMV%) and outcome of patients with acute respiratory failure.

PURPOSE: We have previously shown in patients receiving adaptive support ventilation (ASV) that there existed a Transition %MinVol (TMV%) where the patient's work of breathing began to reduce. In this study, we tested the hypothesis that higher TMV% would be associated with poorer outcome in patients with acute respiratory failure. MATERIALS AND METHODS: In this prospective observational study, we recruited patients with acute respiratory failure on ASV between December 2012 and September 2013 in a mixed ICU. The TMV% was determined by adjusting % MinVol until mandatory respiratory frequency was between 0 and 1breath/min. TMV% was measured on the first two days of mechanical ventilation. RESULTS: A total of 337 patients (age: 70±16years) were recruited. In patients whose TMV% increased between Day 1 and Day 2, aOR for mortality was 7.0 (95%CI=2.7-18.3, p<0.001) compared to patients whose TMV% decreased. In patients whose TMV% was unchanged between Day 1 and Day2, aOR for mortality was 3.91 (95%CI=1.80-8.22, p<0.01). CONCLUSIONS: An increase, or lack of decrease, of TMV% from Day 1 to Day 2 was associated with higher risk of in-hospital death.

Non-malignant respiratory disease among workers in industries using styrene-A review of the evidence.

BACKGROUND: Asthma and obliterative bronchiolitis (OB) cases have occurred among styrene-exposed workers. We aimed to investigate styrene as a risk factor for non-malignant respiratory disease (NMRD). METHODS: From a literature review, we identified case reports and assessed cross-sectional and mortality studies for strength of evidence of positive association (i.e., strong, intermediate, suggestive, none) between styrene exposure and NMRD-related morbidity and mortality. RESULTS: We analyzed 55 articles and two unpublished case reports. Ten OB cases and eight asthma cases were identified. Six (75%) asthma cases had abnormal styrene inhalation challenges. Thirteen (87%) of 15 cross-sectional studies and 12 (50%) of 24 mortality studies provided at least suggestive evidence that styrene was associated with NMRD-related morbidity or mortality. Six (66%) of nine mortality studies assessing chronic obstructive pulmonary disease-related mortality indicated excess mortality. CONCLUSIONS: Available evidence suggests styrene exposure is a potential risk factor for NMRD. Additional studies of styrene-exposed workers are warranted. Am. J. Ind. Med. 60:163-180, 2017. © 2016 Wiley Periodicals, Inc.