Ventilatory Pattern Research Articles

The impact of unilateral diaphragmatic paralysis on sleep-disordered breathing: a scoping review

Unilateral diaphragm paralysis (UDP) may potentially worsen sleep-disordered breathing (SDB). Unilateral diaphragm paralysis has been associated with proximal brachial plexus blockade, such as interscalene and supraclavicular block. The impact of UDP in patients with SDB is not known in this context. The objectives of this scoping review were to explore the associations between UDP and worsening SDB severity, oxygenation, and pulmonary function. A systematic search was developed, peer-reviewed, and applied to Embase, Medline, CINAHL, and Cochrane databases to include studies involving adult patients (≥ 18 yr) with SDB, where the effects of UDP on SDB severity, oxygenation, and pulmonary function were examined. Six studies (n = 100 patients) with UDP and SDB were included. The sample population was derived exclusively from respirology-sleep clinics, and none were surgical patients. Compared with control (no UDP), UDP was associated with an increased respiratory disturbance index, most pronounced during rapid eye movement (REM) sleep and supine sleep. Supine and REM sleep were associated with obstructive and mixed (both obstructive and central) events, respectively. Compared with control, UDP was associated with a lower mean and minimum oxygen saturation and arterial oxygen tension during all sleep stages and in all body positions. The majority of UDP patients were found to have clinically significant reductions in mean forced expiratory volume in one second and forced vital capacity values, consistent with restrictive ventilatory pattern. We observed an association between UDP and increasing SDB severity, particularly during REM sleep and while sleeping in the supine position. Although we identified weaknesses in study design and lack of perioperative data, anesthesiologists should be aware of this association when considering proximal brachial plexus blockade in patients with SDB.

Photoperiod Manipulation Reveals a Light-Driven Component to Daily Patterns of Ventilation in Male C57Bl/6J Mice.

Obstructive sleep apnea is a common sleep disorder that increases risk for cardiovascular disease and mortality. The severity of sleep-disordered breathing in obstructive sleep apnea patients fluctuates with the seasons, opening the possibility that seasonal changes in light duration, or photoperiod, can influence mechanisms of breathing. Photoperiod can have profound effects on internal timekeeping and can reshape metabolic rhythms in mammals. While the daily rhythm in ventilation is largely shaped by the metabolic rate, less is known about whether ventilatory rhythms are altered in accordance with metabolism under different photoperiods. Here, we investigate the relationship between ventilation and metabolism under different photoperiods using whole-body plethysmography and indirect calorimetry. We find that the daily timing of ventilation is chiefly synchronized to dark onset and that light cues are important for maintaining daily ventilatory rhythms. Moreover, changes in ventilatory patterns are not paralleled by changes in oxygen consumption, energy expenditure, or respiratory exchange rate under different photoperiods. We conclude that ventilatory patterns are not only shaped by the metabolic rate and circadian timing but are also influenced by other light-driven factors. Collectively, these findings have clinical implications for the seasonal variations in sleep-disordered breathing found in individuals with obstructive sleep apnea.

Estimating climate change-related impacts on outdoor air pollution infiltration

BackgroundRising temperatures due to climate change are expected to impact human adaptive response, including changes to home cooling and ventilation patterns. These changes may affect air pollution exposures via alteration in residential air exchange rates, affecting indoor infiltration of outdoor particles. We conducted a field study examining associations between particle infiltration and temperature to inform future studies of air pollution health effects. MethodsWe measured indoor fine particulate matter (PM2.5) in Atlanta in 60 homes (810 sampling-days). Indoor-outdoor sulfur ratios were used to estimate particle infiltration, using central site outdoor sulfur concentrations. Linear and mixed-effects models were used to examine particle infiltration ratio-temperature relationships, based on which we incorporated projected meteorological values (Representative Concentration Pathways intermediate scenario RCP 4.5) to estimate particle infiltration ratios in 20-year future (2046–2065) and past (1981–2000) scenarios. ResultsThe mean particle infiltration ratio in Atlanta was 0.70 ± 0.30, with a 0.21 lower ratio in summer compared to transition seasons (spring, fall). Particle infiltration ratios were 0.19 lower in houses using heating, ventilation, and air conditioning (HVAC) systems compared to those not using HVAC. We observed significant associations between particle infiltration ratios and both linear and quadratic models of ambient temperature for homes using natural ventilation and those using HVAC. Future temperature was projected to increase by 2.1 °C in Atlanta, which corresponds to an increase of 0.023 (3.9%) in particle infiltration ratios during cooler months and a decrease of 0.037 (6.2%) during warmer months. DiscussionWe estimated notable changes in particle infiltration ratio in Atlanta for different 20-year periods, with differential seasonal patterns. Moreover, when stratified by HVAC usage, increases in future ambient temperature due to climate change were projected to enhance seasonal differences in PM2.5 infiltration in Atlanta. These analyses can help minimize exposure misclassification in epidemiologic studies of PM2.5, and provide a better understanding of the potential influence of climate change on PM2.5 health effects.

Impact of Curved Vents, Holes and Slots on Thermo-mechanical Behavior of Automobile Disc Brake - FEM Simulation and Validation

Ventilated discs have gained significant attraction for automobile disc brake due to enhanced thermal performance, but the optimal choice needs careful analysis of thermal and structural behaviors. Following the previous studies on solid and straight ventilated discs, the present study considers discs with three new ventilation patterns namely curved vents, curved vents with holes and curved vents with holes and slots. Three-dimensional modeling was done by SOLIDWORKS 15, and finite element simulation was performed by ANSYS 15. In the thermal analysis, the temperature history during one braking cycle was studied for each model, and the structural parameters analyzed include total deformation, Von Mises stress and contact pressure. The study shows that changing from straight vents to curved vents improves thermal performance without affecting the mechanical behavior. Moreover, the thermo-mechanical behavior is further improved by adding holes and slots on the surface, along with curved vents.

Residual Lung Function Impairment Is Associated with Hyperventilation in Patients Recovered from Hospitalised COVID-19: A Cross-Sectional Study.

Patients who have recovered from COVID-19 show persistent symptoms and lung function alterations with a restrictive ventilatory pattern. Few data are available evaluating an extended period of COVID-19 clinical progression. The RESPICOVID study has been designed to evaluate patients’ pulmonary damage previously hospitalised for interstitial pneumonia due to COVID-19. We focused on the arterial blood gas (ABG) analysis variables due to the initial observation that some patients had hypocapnia (arterial partial carbon dioxide pressure-PaCO2 ≤ 35 mmHg). Therefore, we aimed to characterise patients with hypocapnia compared to patients with normocapnia (PaCO2 > 35 mmHg). Data concerning demographic and anthropometric variables, clinical symptoms, hospitalisation, lung function and gas-analysis were collected. Our study comprised 81 patients, of whom 19 (24%) had hypocapnia as compared to the remaining (n = 62, 76%), and defined by lower levels of PaCO2, serum bicarbonate (HCO3−), carbon monoxide diffusion capacity (DLCO), and carbon monoxide transfer coefficient (KCO) with an increased level of pH and arterial partial oxygen pressure (PaO2). KCO was directly correlated with PaCO2 and inversely with pH. In our preliminary report, hypocapnia is associated with a residual lung function impairment in diffusing capacity. We focus on ABG analysis’s informativeness in the follow-up of post-COVID patients.

Trends over Time of Lung Function and Radiological Abnormalities in COVID-19 Pneumonia: A Prospective, Observational, Cohort Study.

Radiological and functional sequelae of Coronavirus Disease 2019 (COVID-19) pneumonia are still poorly understood. This was a prospective, observational, physiological, cohort study on consecutive adult patients with COVID-19 pneumonia admitted in April–May 2020 in the high dependency respiratory unit of L. Sacco University Hospital in Milan (Italy). During hospitalization, patients underwent chest computed tomography (CT), blood gas analysis, spirometry, and lung diffusion capacity for carbon monoxide (DLco), which were repeated 6 weeks post-discharge. Chest CTs were individually read by two expert radiologists, that calculated the total severity score (TSS). Twenty patients completed the study (mean age 58.2 years, 70% males). During the acute phase, mean DLco, alveolar volume (VA), and vital capacity (VC) were 56.0 (16.3), 64.8 (14.0), and 71.7 (16.9) % predicted, respectively, and were inversely associated with PaO2/FiO2 ratio. Fifty percent of patients had a restrictive ventilatory pattern; mean TSS was 7.9 (4.0). At follow up, gas exchange parameters were normalized; consolidations persisted in 10% of cases, while DLco was <80% predicted in 65% of patients and was independently predicted by Log10D-dimer at admission (β −18.675; 95%CI, −28.373–−9.076; p = 0.001). In conclusion, functional abnormalities in COVID-19 pneumonia survivors can persist during follow up and are associated with the severity of the disease.

Study of the design principles of residential buildings in a moderate and humid climate with a natural ventilation approach (Case study: Analysis of simulated openings of a residential building in Amol city)

Background and Objective: Inattention to the climatic features of different regions and the absence of sufficient knowledge of the design principles for optimal use of the potentials of the natural environment leads to higher costs and waste of energy in various fields. Accordingly, due to high humidity in Amol and high cost of ventilation and reduction of moisture in summer, the main objective of this research is to examine and analyze the simulated openings of a residential building with a natural ventilation approach. Method: the present study was carried out in the first step by reviewing the subject literature on this issue and identifying the concepts and principles of residential building design in the field of energy. Then, by supplying the climate information file of Amol from the Weather Meteorology Center for the Climate Consultant software, Design elements were presented. Subsequently, the components were analyzed by Expert Choice software based on the AHP method and computation of component weight led to the final decision in choosing the most important component. Finally, with the simulation of the building in the Flow Design software, the impact of natural ventilation on residential slopes was investigated. Findings: seven components were extracted from the above software as principles of the design and tables of climate interpretation. In the following, with the hierarchical analysis method (AHP), a natural ventilation component with a weight of 0.399 was found to be the main component of the static solar power system. Discussion and conclusion: A natural ventilation pattern was designed in a building with a sloping roof and specific dimensions in the Amol climate. By changing the layout of two 1-square-meter openings on two walls with a height of 2.7 meters in opposite directions at two heights of 1 and 1.7 meters from the floor of the building, 4 airflow modes were simulated with regard to the wind speed of the area in the Flow Design software. In this simulation, by placing the wind tunnel perpendicular to two walls, it can be stated that the best natural ventilation efficiency from these four conditions, is the one with two under-roof structures at 1.7-meter height with the highest wind-suction coefficient of 1.19, which will make a reasonable ventilation and air flow in the simulated residential building.

Identification of trailer heat zones and associated heat stress in weaner pigs transported by road in tropical climates.

Heat stress is major welfare concern during transport of pigs in tropical climates, which can also lead to direct production costs. This study evaluated the dynamics of heat zones through the load and their relationship with heat stress of weaner pigs during road transport in a tropical climate. Both environmental (e.g. temperature and relative humidity) and physiological (e.g. respiratory frequency and lactate) measures were recorded from four vehicle journeys (70km distance, 216 weaner pigs within each trailer load) within Ceará, northeastern Brazil. Geostatistics and fluid dynamics simulation techniques were applied to understand the dynamics of heat zones and ventilation patterns the truckload. Statistics based on canonical discriminant analysis and ANOVA were performed to verify the relationship between heat zones and heat stress in pigs. The results showed that, during transport, the generation of heat zones occurred with different magnitudes along the load (P< 0.05), which was harmonized by the ventilation dynamics. There was a heat core with high energy content, in the front region of the lower deck (LD) of the trailer. In this zone, weaners pigs had higher rectal temperature (+1.8°C temperature difference), respiratory frequency (LD=94±1.3 breaths/min; UD=86±1.3 breaths/min), and blood cortisol concentration (LD=32.9±0.8ng/mL; UD=30.18±0.6ng/mL) (all P< 0.05). Weaners pigs transported in the upper deck (UD) compartments had the highest skin temperature (LD=38.13±0.3°C; UD=38.9±0.22°C) and the highest mean values of blood lactate (LD=65.5±1.11m/M; UD=71.60±1.19m/M) and Creatine kinase (LD=3891.23±69U/L; UD=4107.43±62U/L) (P< 0.05). Weaners transported in compartments of the LD of trailer were more susceptible to heat stress, while weaners in the UD compartments were more susceptible to physical stress and muscle exhaustion. These results provide additional evidence of heat zones within trailer compartments and highlight the requirement for the planning of pig transport operations in tropical climates to mitigate risks of heat stress.

Cardiopulmonary exercise testing in adults with congenital heart disease: Prognostic role in cyanotic patients

IntroductionThere are few and conflicting data concerning cardiopulmonary exercise testing (CPET) in cyanotic congenital heart disease (CHD) in whom the ventilation patterns could be affected. Aim was to assess the functional capacity and stratifying power of CPET in cyanotic CHD. MethodsRetrospective evaluation of CHD adults submitted to CPET in a tertiary centre and followed for at least one year. Patients were divided according to presence of cyanosis (rest oxygen saturation<90%). CPET parameters were analysed as potential predictors of the primary endpoint of cardiac death and hospitalization. Results286 patients, median age 34 years and 3.6 years of follow-up, sixty (21%) cyanotic. Primary endpoint was reached by 49.1% and 22.9% in cyanotic and non-cyanotic patients, respectively. There were significant differences in CPET parameters: cyanotic patients had lowest values for peak oxygen consumption, partial pressure end-tidal carbon dioxide stages, chronotropic index and higher minute ventilation/carbon dioxide production slope and optimal point of ventilation. In cyanotic population the predictors of primary endpoint were: chronotropic index (HR 0.985) in non-Eisenmenger patients; optimal point of ventilation (HR 1.269), rest oxygen saturation (HR 0.621), partial pressure end-tidal carbon dioxide at anaerobic threshold (HR 0.952) and chronotropic index (HR 0.973) after Fontan circulation; partial pressure end-tidal carbon dioxide at rest (HR 1.129) and rest oxygen saturation (HR 1.129) after biventricular repair. ConclusionCyanotic patients had worst exercise capacity and prognosis. Non-traditional CPET parameters as chronotropic index, optimal point of ventilation and partial pressure end-tidal carbon dioxide stages can predict major cardiac events in cyanotic subgroups.

Imaging the Respiratory Transition at Birth: Unraveling the Complexities of the First Breaths of Life.

Rationale: The transition to air breathing at birth is a seminal respiratory event common to all humans, but the intrathoracic processes remain poorly understood. Objectives: The objectives of this prospective, observational study were to describe the spatiotemporal gas flow, aeration, and ventilation patterns within the lung in term neonates undergoing successful respiratory transition. Methods: Electrical impedance tomography was used to image intrathoracic volume patterns for every breath until 6 minutes from birth in neonates born by elective cesearean section and not needing resuscitation. Breaths were classified by video data, and measures of lung aeration, tidal flow conditions, and intrathoracic volume distribution calculated for each inflation. Measurements and Main Results: A total of 1,401 breaths from 17 neonates metall eligibility and data analysis criteria. Stable FRC was obtained by median (interquartile range) 43 (21-77) breaths. Breathing patterns changed from predominantly crying (80.9% first min) to tidal breathing (65.3% sixth min). From birth, tidal ventilation was not uniform within the lung, favoring the right and nondependent regions; P < 0.001 versus left and dependent regions (mixed-effects model). Initial crying created a unique volumetric pattern with delayed midexpiratory gas flow associated with intrathoracic volume redistribution (pendelluft flow) within the lung. This preserved FRC, especially within the dorsal and right regions. Conclusions: The commencement of air breathing at birth generates unique flow and volume states associated with marked spatiotemporal ventilation inhomogeneity not seen elsewhere in respiratory physiology. At birth, neonates innately brake expiratory flow to defend FRC gains and redistribute gas to less aerated regions.

Spirometric restrictive ventilatory pattern and type 2 diabetes mellitus in a tertiary hospital in Cameroon: A comparative study

BackgroundThe objective of this study was to assess the association between spirometric restrictive ventilatory pattern (sRVP) and type 2 diabetes mellitus (T2DM) and investigate factors associated with sRVP in subjects with T2DM. Materials and methodsIn this comparative cross-sectional study, subjects with T2DM (diabetes group) were compared to a group of subjects without diabetes (non-diabetes group) from December 2018 to March 2019 (4months) at the National Obesity Center of the Yaoundé Central Hospital. sRVP was defined as the ratio of forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) above the lower limit of normal, and FVC<80% of predicted values. Logistic regression was used to identify factors associated with sRVP. ResultsOverall 277 subjects were included in each group. The prevalence [95% confidence interval (95% CI)] of sRVP in the diabetes and non-diabetes groups was 39.4 (33.6–45.1) % and 34.3 (28.9–40.1) %, P=0.218. After multivariate analysis, we did not find an independent association between s sRVP and T2DM [odds ratio (95% CI): 1.13 (0.79–1.63), P=0.418]. The only independent factor associated with sRVP in subjects with T2DM was the presence of chronic vascular complications [odds ratio (95% CI): 1.99 (1.11–3.55), P=0.019]. ConclusionOne-third of patients with type 2 diabetes mellitus have sRVP. There is no independent association between sRVP and T2DM. The presence of chronic vascular complications is associated with sRVP in T2DM. Diagnosis of sRVP in subjects with T2DM presenting chronic vascular complications would help to provide a holistic management.

Indoor Air Quality in a Cardiac Care Unit (CCU) under Different Ventilations

A proper ventilation offered warranty for a perfect indoor environment. Indoor air environment includes indoor thermal environment and indoor air quality (IAQ). In this paper a numerical investigation of the indoor environment in different ventilations was accomplished. The Cardiac Care Unit (CCU) in Al-Rifai hospital in Thi-Qar governorate was chosen to be investigated, and its thermal achievement and indoor air quality in the hot summer weather were simulated. For the numerical study, the fluent technique used to set up the physical and numerical model of CCU. An attention has been paid carefully to considerate the distributions of the temperature and the velocity fields, followed by an argument of two different ventilation patterns; up-in and up-out ventilation (UV) and displacement ventilation (DV). After making the comparison, it was noticed that the displacement ventilation (DV) is clearly super than that of the up-in and up-out ventilation (UV) due to improvement in the indoor air quality.

COMPUTATIONAL ANALYSIS OF LOAD VENTILATION IN BROILER TRANSPORT

The characterization of ventilation during the transport of broiler chickens is essential for identifying and characterizing the potential problems of a convective heat flow and its effects on the welfare and the health and production conditions of the chickens. The objective of this study was to evaluate the ventilation patterns in two layout models of a live transport load: conventional (LC) and alternative (LA) with spacers placed between the chicken transport crates. Computational fluid dynamics (CFD) simulations and wind tunnel tests were performed using small scale models. The results showed that the use of spacers between crates (LA model) modified the ventilation patterns and increased the wind circulation between crates. However, wind tunnel tests simulating a density of eight birds/crate were inconclusive because the ventilation was below the sensitivity of the measuring devices used (0.001 m/s). It can be concluded that the use of spacers between the transport crates can modify the ventilation patterns within the load and increase the air circulation between the crates. However, the internal ventilation within the crates has not changed, suggesting the need for studies on the aerodynamics of a transport crate for poultry use.

Rock glaciers and related cold rocky landforms: Overlooked climate refugia for mountain biodiversity.

Mountains are global biodiversity hotspots where cold environments and their associated ecological communities are threatened by climate warming. Considerable research attention has been devoted to understanding the ecological effects of alpine glacier and snowfield recession. However, much less attention has been given to identifying climate refugia in mountain ecosystems where present-day environmental conditions will be maintained, at least in the near-term, as other habitats change. Around the world, montane communities of microbes, animals, and plants live on, adjacent to, and downstream of rock glaciers and related cold rocky landforms (CRL). These geomorphological features have been overlooked in the ecological literature despite being extremely common in mountain ranges worldwide with a propensity to support cold and stable habitats for aquatic and terrestrial biodiversity. CRLs are less responsive to atmospheric warming than alpine glaciers and snowfields due to the insulating nature and thermal inertia of their debris cover paired with their internal ventilation patterns. Thus, CRLs are likely to remain on the landscape after adjacent glaciers and snowfields have melted, thereby providing longer-term cold habitat for biodiversity living on and downstream of them. Here, we show that CRLs will likely act as key climate refugia for terrestrial and aquatic biodiversity in mountain ecosystems, offer guidelines for incorporating CRLs into conservation practices, and identify areas for future research.

Transcutaneous carbon dioxide pattern and trend over time in preterm infants.

BackgroundChronic lung disease remains a burden for extremely preterm infants. The changes in ventilation over time and optimal ventilatory management remains unknown. Newer, non-invasive technologies provide insight into these patterns.MethodsThis single-center prospective cohort study enrolled infants ≤32 0/7 weeks. We obtained epochs of transcutaneous carbon dioxide (TcCO2) measurements twice each week to describe the pattern of hypercarbia throughout their hospitalization.ResultsPatterns of hypercarbia varied based on birth gestational age and post-menstrual age (PMA) (p = 0.03), regardless of respiratory support. Infants receiving the most respiratory support had values 16–21 mmHg higher than those on room air (p < 0.001). Infants born at the youngest gestational ages had the greatest total change but the rate of change was slower (p = 0.049) compared to infants born at later gestational ages. All infants had TcCO2 values stabilize by 31–33 weeks PMA, when values were not significantly different compared to discharge. No rebound was observed when infants weaned off invasive support.ConclusionsHypercarbia improves as infants approached 31–33 weeks PMA. Hypercarbia was the highest in the most immature infants and improved with age and growth despite weaning respiratory support.Impact This study describes the evolution of hypercarbia as very preterm infants grow and develop.The pattern of ventilation is significantly different depending on the gestational age at birth and post-menstrual age.Average transcutaneous carbon dioxide (TCO2) decreased over time as infants became more mature despite weaning respiratory support. This improvement was most significant in infants born at the lowest gestational ages.

Effect of continuous positive airway pressure associated to exercise on the breathing pattern and heart rate variability of patients undergoing coronary artery bypass grafting surgery: a randomized controlled trial.

Continuous positive airway pressure (CPAP) has been used to improve gas exchange and diaphragmatic function, among others benefits. Moreover, it can be used to increase exercise tolerance and positively influence ventilatory function and breathing pattern (BP) during exercise. However, there is no information about the long-term effects of CPAP, as an adjunct to an inpatient cardiac rehabilitation (CR) program, on BP and heart rate variability (HRV) of patients after coronary artery bypass grafting surgery (CABG). Twenty patients were allocated to receive, after randomization, standard inpatient CR without CPAP (control group - CG) or CR with CPAP between 10 to 12 cmH2O (CPAP group - CPG) associated with the exercises. Participants were assessed preoperatively and on the discharge day, in the sitting rest position. Outcome measurements included BP variables, collected by respiratory inductive plethysmography, and HRV, collected by polar precision performance. The CPG presented lower values of percent rib cage inspiratory and expiratory contributions to tidal volume (%RCi and %RCe) at discharge time, compared to CG. No statistical differences between groups were observed for HRV variables and both groups presented lower values of these indices, compared to preoperative ones. In this context, the patients who received CPAP throughout the whole rehabilitation program were discharged with a better BP, which could indicate more synchronized breathing. CPAP did not influence cardiac autonomic modulation in the long term.

The impact of diabetes mellitus on ventilatory function among South-Eastern Nigerians

Background: The pulmonary affectation by diabetes mellitus (DM) has not received adequate attention, and as such, there is paucity of data on the impact of DM on ventilatory function especially in South-Eastern, Nigeria. This study, therefore, aimed to determine the impact of type 2 DM on ventilatory function as observed at a tertiary health care facility in South-Eastern Nigeria. Materials and Methods: This was a comparative cross-sectional study of 100 consenting type 2 DM patients aged between 30 and 65 years, and 100 consenting, normal, adequately matched subjects. Anthropometric parameters were obtained from both study groups, and spirometry was done using spirolab III, version 1.7. Predicted ventilatory parameters were calculated using Nigerian equations. SPSS version 21 was used for data analysis. Results: A total of 100 type 2 DM patients and 100 normal control subjects were studied. There were 49 males and 51 females with type 2 DM. Comparatively, 51 of the control group were males while 49 were females. The mean FVC, FEV1, FEF25-75, and PEFR, were significantly lower in the type 2 DM group than in the control group (P values of 0.010, 0.015, <0.001, 0.006 respectively). Likewise percentage predicted FVC, FEV1 and PEFR were significantly lower in the type 2 DM patients (P values <0.05). As much as 22% of the type 2 DM subjects had restrictive pattern while 2% had obstructive pattern. Long duration of DM (10 years or more) was associated with increased likelihood of developing restrictive ventilatory pattern (P < 0.001, odds ratio 14.224). Conclusion: Type 2 DM is associated with restrictive ventilatory dysfunction. Duration of DM of 10 years or more is an independent predictor of restrictive ventilatory pattern among type 2 DM subjects.

Early Hepatic Encephalopathy after a Transjugular Intrahepatic Portosystemic Shunt Procedure: Case Report

Patients with decompensated hepatic cirrhosis may present systemic alterations and dysfunction of multiple organs. Ascites, portal hypertension, esophageal varices, and hepatic encephalopathy are common complications arising from cirrhosis. The aim of this paper is to report a case of a patient with liver cirrhosis and the complications of a transjugular intrahepatic portosystemic shunt. Male, elderly, and ex-alcoholic, diagnosed with liver cirrhosis, ascites, and esophageal varices. He underwent transjugular intrahepatic portosystemic shunt due to portal hypertension and returned to the hospital after 24 hours with agitation and mental confusion. He had a bowel movement stop, neurological worsening, loss of renal function, hepatic hydrothorax, hepatic encephalopathy, hypernatremia, hypocalcemia, and hypophosphatemia. He underwent a new procedure to occlude the transjugular intrahepatic portosystemic shunt, showing improvement of the mental status and ascites. However, continued with decompensation and hydro-electrolytic disorders. He evolved with worsening of the ventilatory pattern, and neurological and renal function, with a fatal outcome. Esophageal varices due to portal hypertension can be corrected with the transjugular intrahepatic portosystemic shunt. However, complications such as hypernatremia, hepatic hydrothorax, and hepatic encephalopathy may occur. Therefore, there is a need for reintervention to shunt or reduce its caliber. Thus, for patients with advanced age and decompensated cirrhosis, the potential risks and benefits of this procedure should be carefully evaluated due to the risk of complications and death.

Non-Hodgkin’s Lymphoma Associated with Metastatic Lung Cancer: Case Report

Lymphomas are neoplastic transformations that affect lymphoid cells. Diffuse large B-cell non-Hodgkin’s lymphoma has a high degree of cell proliferation, accounting for 30% of all lymphomas. Lung cancer is the leading cause of death worldwide and the recommended treatment is chemotherapy. Among the main complications resulting from non-Hodgkin’s lymphoma, lung cancer and chemotherapy used in their treatment, we can mention sepsis, acute kidney injury and febrile neutropenia. Febrile neutropenia can occur by suppressing the production of neutrophils. Sepsis, a widespread infection, is the main cause of acute kidney injury, which can also be caused by hydroelectrolytic complications or by nephrotoxicity. This is a report of a smoking patient with metastatic lung cancer who sought care due to progressive dysphagia, cough with chest pain, fever, and lower airways critical obstruction due to mediastinal lymphadenopathy, being diagnosed with diffuse large B-cell non-Hodgkin’s lymphoma. The patient evolved to death because of a significant worsening of the ventilatory pattern of multifactorial cause, mainly due to sepsis, acute kidney injury, and febrile neutropenia. The patient had mostly classic characteristics of her comorbidities, however, the overlapping of interrelated comorbidities led to the outcome of death. What is unusual about the present case report is that the patient’s characteristics, such as age, sex, and ethnicity, are opposite to those described as risk factors for diffuse large B-cell non-Hodgkin’s lymphoma.

The impact of ventilation patterns on calcite dissolution rates within karst conduits

Erosion rates in streams vary dramatically over time, as differences in streamflow and sediment load enhance or inhibit erosion processes. Within cave streams, and other bedrock channels incising soluble rocks, changes in water chemistry are an important factor in determining how erosion rates will vary in both time and space. Prior studies in surface streams, springs, and caves suggest that variation in dissolved CO2 is the strongest control on variation in calcite dissolution rates. However, the controls on CO2 variation remain poorly quantified. Limited data suggest that ventilation of karst systems can substantially influence dissolved CO2 within karst conduits. However, the interactions among cave ventilation, air–water CO2 exchange, and dissolution dynamics have not been studied in detail. In this study, three years of time series measurements of dissolved and gaseous CO2, cave airflow velocity, and specific conductance from Blowing Springs Cave, Arkansas, were analyzed and used to estimate continuous calcite dissolution rates and quantify the correlations between those rates and potential physical and chemical drivers. We find that chimney effect airflow creates temperature-driven switches in airflow direction, and that the resulting seasonal changes in airflow regulate both gaseous and dissolved CO2 within the cave. As in previous studies, partial pressure of CO2 (pCO2) is the strongest chemical control of dissolution rate variability. However, we also show that cave airflow direction, rather than streamflow, is the strongest physical driver of changes in dissolution rate, contrary to the typical situation in surface channel erosion where floods largely determine the timing and extent of geomorphic work. At the study site, chemical erosion is typically active in the summer, during periods of cave downdraft (airflow from upper to lower entrances), and inactive in the winter, during updraft (airflow from lower to upper entrances). Storms provide only minor perturbations to this overall pattern. We also find that airflow direction modulates dissolution rate variation during storms, with higher storm variability during updraft than during downdraft. Finally, we compare our results with the limited set of other studies that have examined dissolution rate variation within cave streams and draw an initial hypothesis that evolution of cave ventilation patterns strongly impacts how dissolution rate dynamics evolve over the lifetime of karst conduits.