Irregular Respiration Research Articles

Comments on the paper "Data-driven gating (DDG)-based motion match for improved CTAC registration. EJNMMI Physics. 2024;11(1):42."

Misregistration between CT and PET in PET/CT is mainly caused by respiratory motion or irregular respiration during the CT scan in PET/CT. Other than repeat CT, repeat PET/CT, or data-driven gated (DDG) CT, there is no practical approach to mitigate the misregistration artifacts and subsequent CT attenuation correction (CTAC) of the PET data. DDG PET derives a respiratory motion model based on the multiple phases of PET images without hardware gating and it allows for a potential correction of the misregistration artifacts based on the respiratory motion model. The purpose of this commentary was to compare the recent two publications on matching the random phase of helical CT with one of the PET phases derived from the motion model of DDG PET and warping the misregistered helical CT for CTAC of and registration with PET or DDG PET. The two publications were similar in methodology. However, the data sets used for the comparison were different and could potentially impact their conclusions.

Physiological Regularity and Synchrony in Individuals with Gaming Disorder.

Individuals with gaming disorder (GD) show emotional dysregulation and autonomic dysfunction in daily life. Although studies have shown that the relaxation method of breathing exercise (BE) improves cardiopulmonary synchrony, the physiological regularity and synchrony of GD remain unclear. In this study, we investigated the regularities of pulse wave (PW), thoracic wall movement (TWM), and abdominal wall movement (AWM) using sample entropy (SE) and assessed the vascular-respiratory and TWM-AWM synchrony using cross-sample entropy (CSE). Twenty individuals with GD and 26 healthy control (HC) individuals participated in baseline, gaming, and recovery stages, both before and after BEs. The results showed that both groups had significantly higher SETWM, SEAWM, and CSETWM-AWM during gaming than baseline. Before BE, CSEPW-TWM and CSEPW-AWM during gaming were considerably higher in the GD group than in the HC group. Compared to before BE, both groups had decreased SETWM and CSETWM-AWM during gaming, particularly in the HC group. Online gaming may induce pulse wave and respiratory irregularities, as well as thoracic-abdominal wall movement asynchrony. Individuals with GD who engage in prolonged gaming periods may exhibit lower vascular-respiratory synchrony compared to the HC group. SETWM, SEAWM, CSETWM-AWM, CSEPW-TWM, and CSEPW-AWM may serve as biomarkers for assessing the risk of GD. BE may improve TWM regularity and vascular-respiratory synchrony during gaming, potentially alleviating addictive behavior.

Optical fiber sensor for wearable and accurate human respiratory monitoring.

Accurate respiratory monitoring is of great significance in assessing and analyzing physical health, and preventing respiratory diseases. The recently emerged wearable respiratory sensors are confronted with the challenges such as complex fabrication processes, limited accuracy, and stringent wearing requirements. An optical fiber sensor for accurate human respiratory monitoring is proposed and experimentally verified. The sensor head is composed of a piece of seven core fiber sandwiched between two single-mode fibers by two fiber bitapers, which is embedded in a textile sheet and freely worn on the upper body. An efficient signal demodulation system is set up to acquire the respiratory signal, while Fourier transform (FFT) and short-time Fourier transform (STFT) methods are used to analyze the measured signal. Six volunteers are invited to perform the respiratory experiment, and the experimental results demonstrate that the sensor can accurately detect and distinguish respiratory signals under different humans, different states (normal, slow, fast), different body parts (abdomen, chest, back), different postures (standing, sitting, lying), and irregular respiration. The Pearson correlation coefficient of the sensor is higher than 0.9, which is consistent with commercial respiratory sensor. Meanwhile, the instability of the sensor is 0.003 Hz for the same volunteer in 6 months. The sensor has the advantages of high sensitivity, good stability and wearing comfort, showing good potential in healthcare applications.

The Prediction of Stress in Radiation Therapy: Integrating Artificial Intelligence with Biological Signals.

This study aimed to predict stress in patients using artificial intelligence (AI) from biological signals and verify the effect of stress on respiratory irregularity. We measured 123 cases in 41 patients and calculated stress scores with seven stress-related features derived from heart-rate variability. The distribution and trends of stress scores across the treatment period were analyzed. Before-treatment information was used to predict the stress features during treatment. AI models included both non-pretrained (decision tree, random forest, support vector machine, long short-term memory (LSTM), and transformer) and pretrained (ChatGPT) models. Performance was evaluated using 10-fold cross-validation, exact match ratio, accuracy, recall, precision, and F1 score. Respiratory irregularities were calculated in phase and amplitude and analyzed for correlation with stress score. Over 90% of the patients experienced stress during radiation therapy. LSTM and prompt engineering GPT4.0 had the highest accuracy (feature classification, LSTM: 0.703, GPT4.0: 0.659; stress classification, LSTM: 0.846, GPT4.0: 0.769). A 10% increase in stress score was associated with a 0.286 higher phase irregularity (p < 0.025). Our research pioneers the use of AI and biological signals for stress prediction in patients undergoing radiation therapy, potentially identifying those needing psychological support and suggesting methods to improve radiotherapy effectiveness through stress management.

Respiratory Effects of Benzodiazepine in Patients with Advanced-Stage Cancer Receiving Opioid Analgesics: A Prospective Observational Study.

Despite the risk of respiratory depression, benzodiazepines are often prescribed to patients receiving palliative care owing to their efficacy in symptom control. Opioids, which also cause respiratory depression, are often administered to patients with advanced-stage cancer. However, the additive effect of the two drugs has not been systematically analyzed. This prospective observational study aimed to determine the respiratory effects of coadministration of benzodiazepines and opioids in terminally ill patients with cancer. The respiratory variables (primary endpoint) and activity index (ACI) (secondary endpoint) of 24 patients were assessed using a continuous noncontact, nonrestraining vital sign monitor placed under the legs of the bed. The respiratory rate (RR) changed from 12.0 ± 3.9/min to 10.3 ± 3.3/min (n = 24, p = 0.0005) following administration of the first dose of benzodiazepine in addition to regular opioid treatment, indicating no difference (p > 0.83) from the decrease in the RR observed on the previous day at the same time (12.1 ± 3.3/min to 10.3 ± 3.4/min). No increase in apnea-hypopnea frequency and respiratory irregularity or no decrease in respiratory size was observed. The ACI showed a significant decrease following the administration of benzodiazepine, suggesting remission of the symptoms. The effect of five repeated doses of benzodiazepines in nine patients showed no significant change in the respiratory variables compared with the first dose. Addition of single or consecutive benzodiazepine-type drugs at clinically useful dose in patients receiving palliative care for cancer with opioid analgesics, readily exposed to respiratory depression, was observed with a decreased RR similar to the decrease observed during sleep with opioid alone.

Feasibility of Spectral Analysis as a Tool in Nursing Research to Quantify Patterns of Respiration in Premature Infants.

Respiratory difficulties are a common concern in preterm infants, and they can lead to long-term health problems. Few studies have investigated the use of spectral analysis as a biomarker to quantify respiration patterns in preterm infants. To evaluate the feasibility of using spectral analysis of heart rate variability as a biomarker for the quantification of respiratory patterns in very-low-birth-weight preterm infants compared to direct observation. In a comparative, small-scale feasibility study, 18 preterm infants born during their 27th to 28th gestational week (weighing <1500 grams) participated by convenience. Respiratory patterns (regular or irregular; shallow or deep) were directly observed on the 28th week during playback of speech recording. Heart rate variability was simultaneously measured using spectral analysis of heart periods, from which the mean values influenced by respiratory sinus arrhythmia (frequencies of 0.30-1.0 Hz) were compared to each observed respiratory pattern. The magnitudes of respiratory sinus arrhythmia and the area under the curve were determined. The magnitude of respiratory sinus arrhythmia (frequencies of 0.30-1.0 Hz) in infants observed to be displaying irregular shallow respiration was greater than that in infants with regular deep respiration. Further, there was a shift from lower frequencies (frequency peak = 0.30 Hz) to higher frequencies (peak = 0.70 Hz). In contrast with direct observation, spectral analysis allowed for the quantification of respiratory patterns in a vulnerable population of preterm infants of interest to the nursing scientific and practice community. Future directions include applying this biomarker to evaluate both developmental and pathological trends in the respiratory patterns of preterm infants.

Classification of Adventitious Sounds Combining Cochleogram and Vision Transformers.

Early identification of respiratory irregularities is critical for improving lung health and reducing global mortality rates. The analysis of respiratory sounds plays a significant role in characterizing the respiratory system's condition and identifying abnormalities. The main contribution of this study is to investigate the performance when the input data, represented by cochleogram, is used to feed the Vision Transformer (ViT) architecture, since this input-classifier combination is the first time it has been applied to adventitious sound classification to our knowledge. Although ViT has shown promising results in audio classification tasks by applying self-attention to spectrogram patches, we extend this approach by applying the cochleogram, which captures specific spectro-temporal features of adventitious sounds. The proposed methodology is evaluated on the ICBHI dataset. We compare the classification performance of ViT with other state-of-the-art CNN approaches using spectrogram, Mel frequency cepstral coefficients, constant-Q transform, and cochleogram as input data. Our results confirm the superior classification performance combining cochleogram and ViT, highlighting the potential of ViT for reliable respiratory sound classification. This study contributes to the ongoing efforts in developing automatic intelligent techniques with the aim to significantly augment the speed and effectiveness of respiratory disease detection, thereby addressing a critical need in the medical field.

Breathing irregularities in spontaneously hypertensive neonate rats

An excessive sympathetic drive is commonly observed in hypertensive patients and critically contributes to increasing arterial pressure levels. The quality of postnatal life can impact sympathetic control in adulthood. Spontaneously hypertensive (SH) rats, an experimental model of neurogenic hypertension, exhibit breathing irregularities in adult life. In this study, we investigated whether SH rats display breathing abnormalities after birth, which could be a risk factor for developing sympathetic overactivity. Using head-out plethysmography, we found that the neonate (P0-2, male and female) SH rats (n=9) exhibited lower minute ventilation than age-matched normotensive rats (NT, n=14; 816±177 vs 1261±189 ml/min/kg, P&lt;0.05) under resting conditions, mainly due to reductions in respiratory frequency (93±15 vs 132±13 cpm, P&lt;0.05). The reduced baseline ventilation in the SH group was accompanied by a greater prevalence of periods of apneas and respiratory irregularities (P&lt;0.05). Under hypoxia conditions (10% O2, 10 min), SH and NT rats (n=9/each) mounted similar transient increases in minute ventilation during the initial period of exposure due to increments in tidal volume. In contrast, the respiratory frequency in the SH rats decreased progressively below baseline levels during hypoxia exposure (42% reduction, P&lt;0.05), while it remained similar to pre-hypoxia values in the control group. In rhythmic in vitro preparations from neonate SH rats (n=2), we identified ectopic bursts in the hypoglossal activity and prolonged inspiratory-related bursts in the preBötzinger complex compared to preparations from NT rats (n=2). Our findings indicate that breathing irregularities in SH rats are present from birth and could be linked to dysfunctions in the inspiratory rhythm-generating network. Financial support: FAPESP, CNPq. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Compare image quality of T2-weighted imaging with different phase acceleration factors.

Previous studies demonstrated that adjusting the phase acceleration (PA) factors could influence image quality. To improve image quality and decrease respiratory artifacts of lesions in the liver on T2-weighted image by adjusting PA factor and number of excitation (NEX). Sixty consecutive patients with hepatic lesions were enrolled in this prospective research between May 2020 and June 2020. All patients had 3.0T magnetic resonance imaging with 4 sequences (combining PA factors and NEXs, the former was 2 and 3, the latter were 1.5 and 2, respectively, with the same other scanning parameters). Two readers used 5-point quality scales to assess image quality. The signal intensity was measured by drawing regions of interest in the liver, spleen, and background on the T2-weighted imaging. Artifacts, overall image impression, and vascular conspicuity were better when the PA factor was 3 than 2. Artifacts and vascular conspicuity were better when NEX was 2 than 1.5. PA factor 3 and NEX 2 got a higher score in 5-point quality scales and less scan time than the other 3 sequences. Meanwhile, the signal-to-noise ratio of PA factor 3 and NEX 2 was best among these 4 sequences. PA factor and NEX could influence the imaging quality and lesion-to-hepatic contrast in detecting hepatic lesions on T2-weighted images. PA factor 3 and NEX 2 may have a positive effect in the clinic, especially for those with irregular respiration, as it decreased artifacts and reduced scan time.

Evaluation of genotoxicity and 13-week subchronic toxicity of root of Asarum heterotropoides var. seoulense (Nakai) Kitag

Ethnopharmacological relevanceAsarum heterotropoides var. seoulense (Nakai) Kitag is a traditional herbal medicine used in Korea and China. It is effective in aphthous stomatitis, local anesthesia, headache, toothache, gingivitis, and inflammatory diseases. However, information on the toxicity of the root of Asarum heterotropoides var. seoulense (Nakai) Kitag (AR) is limited. Therefore, preclinical toxicity studies on AR are needed to reduce the risk of excessive intake. Aim of the studyWe aimed to evaluate genotoxicity and the potential toxicity due to repeated administration of AR powder. Materials and methodsIn vitro bacterial reverse mutation assay (Ames), in vitro chromosomal aberration assay (CA), and in vivo micronucleus (MN) assay in ICR mice were conducted. As positive results were obtained in Ames and CA assays, alkaline comet assay and pig-a gene mutation test were conducted for confirmation. For evaluating the general toxicity of AR powder, a 13-week subchronic toxicity test was conducted, after determining the dose by performing a single and a 4-week dose range finding (DRF) test. A total of 152 Sprague-Dawley (SD) rats were orally administered AR powder at doses of 0, 150, 350, 500, 1000, and 2000 mg/kg/day in the 13-week subchronic toxicity test. Hematology, clinical chemistry, urinalysis, organ weight, macro-, and microscopic examination were conducted after rat necropsy. ResultsAR powder induced genotoxicity evidenced in the Ames test at 187.5, 750, 375, and 1500 μg/plate of TA100, TA98, TA1537, and E. coli WP2uvrA in the presence and absence of S9, respectively; CA test at 790 μg/mL for 6 h in the presence of S-9; 75 μg/mL for 6 h in the absence of S-9, and 70 μg/mL for 22 h in the absence of S-9 in the stomach in the comet assay but not in MN and pig-a assays. In the 13-week subchronic toxicity study, clinical signs including irregular respiration, noisy respiration, salivation, and decreased body weight or food consumption were observed in males and females in the 2000 mg/kg/day group. In hematology tests, clinical chemistry, urinalysis, organ weight, and macroscopic examination, changes were observed in the dose groups of 500 mg/kg/day and above. Microscopic examination revealed hyperplasia of the stomach as a test-related change. Hepatocellular adenoma and changes in liver-related clinical chemistry parameters were observed. The rat No Observed Adverse Effect Level (NOAEL) was 150 mg/kg/day in males and <150 mg/kg/day in females. ConclusionsAR powder is potentially toxic to the liver and stomach and should be used with caution in humans. A long-term study on carcinogenicity is necessitated because DNA damage or changes in tissue lesions were observed in SD rats.

System requirements to improve adaptive 4-dimensional computed tomography (4D CT) imaging

Four-Dimensional Computed Tomography (4D CT) is of increasing importance in stereotactic body radiotherapy (SBRT) treatments affected by respiratory motion. However, 4D CT images are commonly impacted by irregular breathing, causing image artifacts that can propagate through to treatment, negatively effecting local control. REspiratory Adaptive CT (REACT) is a real-time gating method demonstrated to reduce motion artifacts by avoiding imaging during irregular respiration. Despite artifact reduction seen through in silico and clinical phantom-based studies, REACT has not been able to remove all artifacts. Here, we explore several hardware and software latencies (gantry rotation time, couch shifts, acquisition delays and phase calculation method) inherently linked to REACT and 4D CT in general and investigate their contribution to artifacts beyond those caused by irregular breathing. Imaging was simulated using the digital extended cardiac-torso (XCAT) phantom for fifty patient-measured respiratory traces. Imaging protocols included conventional cine 4D CT and five REACT scans with systematically varied parameters to test the effect of different latencies on artifacts. Artifacts were quantified by comparing the image normalized cross correlation across couch transition points and determining the volume error compared to a static phantom ground truth both as a total error and individually across pixel rows in the main plane of motion. Artifacts were determined for each lung, the whole heart and lung tumour and were compared back to conventional 4D CT and REACT with standard clinical scanning parameters. The gantry rotation time and acquisition delay were found to have the largest impact on reducing image artifacts and should be the focus of future development. The phase calculation method was also found to influence motion artifacts and should potentially be assessed on a patient-to-patient basis. Finally, the correlation between an increase in artifacts and baseline drift suggests that longer scan times allowing drift to occur may impact image quality.

Advanced cutting strategy for navigated, robot-driven laser craniotomy for stereoelectroencephalography: An in Vivo non-recovery animal study.

Objectives: In this study we aimed to present an updated cutting strategy and updated hardware for a new camera system that can increase cut-through detection using a cold ablation robot-guided laser osteotome. Methods: We performed a preoperative computed tomography scan of each animal. The laser was mounted on a robotic arm and guided by a navigation system based on a tracking camera. Surgery was performed with animals in the prone position. A new cutting strategy was implemented consisting of two circular paths involving inner (full cylindric) and outer (hollow cylindric) sections, with three different ablation phases. The depth electrodes were inserted after cut-through detection was confirmed on either the coaxial camera system or optical coherence tomography signal. Results: A total of 71 precision bone channels were cut in four pig specimens using a robot-guided laser. No signs of hemodynamic or respiratory irregularities were observed during anesthesia. All bone channels were created using the advanced cutting strategy. The new cutting strategy showed no irregularities in either cylindrical (parallel walled; n = 38, 45° = 10, 60° = 14, 90° = 14) or anticonical (walls widening by 2 degrees; n = 33, 45° = 11, 60° = 13, 90° = 9) bone channels. The entrance hole diameters ranged from 2.25–3.7 mm and the exit hole diameters ranged from 1.25 to 2.82 mm. Anchor bolts were successfully inserted in all bone channels. No unintended damage to the cortex was detected after laser guided craniotomy. Conclusion: The new cutting strategy showed promising results in more than 70 precision angulated cylindrical and anti-conical bone channels in this large, in vivo non-recovery animal study. Our findings indicate that the coaxial camera system is feasible for cut-through detection.

Self Adaptive Fuzzy Controller for Supplementary Oxygen Supply to the Respiratory Distress Patients

In this paper, respiratory irregularities of humans are investigated, and a self Adaptive Fuzzy Logic-based Proportional plus Derivative Controller (AFLPDC) is designed to provide a controlled supply of oxygen to the patient, suffering from breathlessness. The Fuzzy Logic-based Proportional plus Derivative Controller (FLPDC) is tuned, by implementing an adaptive scheme, which provides desired control action according to the process parameter variations. The electrical equivalent model of the respiratory system is developed, and the model is validated with the help of a Spirometer and MATLAB System Identification Toolbox. To build up this model, the respiratory tract is well thought out into four sections: the nasal cavity, trachea, bronchi, and finally, the alveolar sacs. Each of these sections is represented as a series of combinations of Resistance, Inductance, and Compliance. The control capability of the proposed AFLPDC is investigated on the derived respiratory model. The supply of the desired level of supplemental oxygen by AFLPDC to the patients suffering from the diseases like Bronchitis and Emphysema during respiratory dysfunction is observed in the MATLAB SIMULINK environment without human intervention. The response revealed by AFLPDC is compared with the responses of the conventional PD controller and the Fuzzy Logic-based PD controller (FLPDC).

Respiratory analysis during sleep using a chest-worn accelerometer: A machine learning approach

Objective:There is a great interest in observing breathing patterns during sleep, as sleep disturbances can be caused by respiratory irregularity and cessations. In this paper, we introduce the first steps to an accelerometer-based screening tool for respiratory rate estimation and a novel approach towards detecting breathing cessations such as apnea/hypopnea, by extending and combining established signal processing routines with machine learning. Methods:From a single chest-worn accelerometer, we estimate the respiratory rate based on the inhalation/exhalation movements of the chest and carry out a full overnight validation. On this basis, we build a set of features customized to detect irregular respiratory activity, including a novel feature: the respiratory peak variance (RPV). From thirteen healthy subjects, a classification model was trained, validated, and tested with over 98 h of PSG-labeled accelerometer data. Results:The algorithm estimated the respiratory rate with a mean difference of 1.8 breaths per minute compared to respiratory inductance plethysmography during overnight PSGs. The machine learning classifier detected respiratory cessations with a sensitivity and specificity of 76.05% and 70.05% respectively, with an overall accuracy of 70.95%. Conclusion:We successfully demonstrated the potential of a novel respiratory feature set in a preliminary application with young healthy volunteers for respiratory rate estimation and in identifying apnea/hypopnea events during overnight sleep. Significance:We present a simple and unobtrusive wearable system that can serve as a home screening tool for sleep-related breathing disorders.

Reactive medullary astrocytes are associated with RVLM neuroinflammation in heart failure rats

Heart failure with preserved ejection fraction (HFpEF) is a complex clinical syndrome. Brain inflammation has been suggested to play a key role in HFpEF progression by modulating the activity of several brainstem circuits encompassing cardiovascular and respiratory regulation. Indeed, we recently reported RVLM‐C1 catecholaminergic neurons hyperactivity in rats with HFpEF. However, the precise mechanism underpinning changes in C1 activity in HFpEF remains to be determined. Interestingly, glial cell activation within the RVLM (particularly astrocytes) has been shown to modulate C1 neuron activity. Despite this evidence whether astrocytes may become activated in HFPEF has not been previously studied. Accordingly, we aimed to determine changes in astrocyte activity within the RVLM of HFpEF rats and its relation with RVLM neuroinflammatory status. Adult male Sprague‐Dawley rats (250 g) underwent volume overload to induce HFpEF. Eight weeks after surgical induction of HFpEF, rats underwent respiratory function recordings in freely moving conditions using whole‐body plethysmography. At the end of the physiological experiments, brains were harvested, fixed in 4% PFA and processed for immunohistochemical analysis. Immunofluorescence for tyrosine hydroxylase and glial fibrillary acidic protein (GFAP) were performed in 25 μm free‐floating brainstem sections containing the RVLM. Sholl analysis was performed to evaluate astrocytic morphological differences between HFpEF and Sham rats (total length of processes, # of processes, maximum intersection radius, # of intersections). RVLM neuroinflammatory status was measured in micropunches by immunoblot (GFAP) and qPCR (TNF‐α, IL‐1β). Compared to Sham rats, HFpEF animals showed clear signs of astrocyte reactivity evidenced by increases in the number of astrocyte processes (11.27 ± 1.096 vs. 18.64 ± 1.333; HFpEF vs. Sham, respectively), length of astrocyte processes (267.5 ± 17.92μm vs. 392.8 ± 22.53μm; HFpEF vs. Sham, respectively) and number of intersections (3.410 ± 0,25 vs. 4.538 ± 0.317; HFpEF vs. Sham, respectively). Consistently, we found an increased GFAP expression within the RVLM of HFpEF rats compared with Sham rats (99.9 ± 5.9 vs. 135.3 ± 15.8; HFpEF vs. Sham, respectively. In addition, we found that TNF‐α and IL‐1β were both augmented in HFpEF (~7 and ~3 fold, respectively) compared to Sham. Notably, respiratory dysfunction observed in HFpEF were significantly and positively correlated with the degree of activation of RVLM astrocytes. Indeed, respiratory irregularity score (R2 = 0.98; p&lt;0.05), short‐term variability of the breath‐to‐breath interval (R2 = 0.98; p&lt;0.05), and apneas/hypopneas index (R2 = 0.94; p&lt;0.05)) were all related to GFAP expression in HFpEF rats. Our findings showed the presence of reactive astrocytes within the RVLM of HFpEF animals and that the degree of astrocyte activity was associated with RVLM neuroinflammation. Together our results suggest that increases in astrocyte reactivity in HFpEF may help to induce/maintain a pro‐iflammatory niche within the RVLM that ultimately lead to C1 neuron activity alterations.

A low albumin level as a risk factor for transient severe motion artifact induced by gadoxetate disodium administration: A retrospective observational study with free-breathing dynamic MRI and an experimental study in rats.

ObjectivesIn the arterial phase of gadoxetate disodium administration for dynamic MRI, transient severe motion (TSM) sometimes occurs, making image evaluation difficult. This study was to identify risk factors for TSM in a clinical study, and confirm them and investigate the cause in an animal study.MethodsA retrospective, single-center, observational study included patients who underwent dynamic MRI using gadoxetate disodium for the first time from April 2016 to September 2019 and free-breathing MRI was performed. Differences in clinical characteristics and laboratory tests between the presence and absence of TSM were examined. Animal experiments were conducted in 50 rats; gadoxetate disodium was injected into three sites (distal inferior vena cava (IVC), ascending aorta, and descending aorta) to identify the organ which triggers respiratory irregularities. Phosphate-buffered saline and gadopentetate dimeglumine were also injected into the distal IVC. In addition, to evaluate the effect of albumin, gadoxetate disodium was diluted with phosphate-buffered saline or 5% human serum albumin and injected into the ascending aorta. The time course of the respiratory rate was monitored and evaluated.Results20 of 51 (39.2%) patients showed TSM. On multivariable analysis, a low albumin level was an independent risk factor (P = .035). Gadoxetate disodium administration caused significant tachypnea compared to gadopentetate dimeglumine or PBS (an elevation of 16.6 vs 3.0 or 4.3 breaths/min; both P < .001) in rats. The starting time of tachypnea was earlier with injection into the ascending aorta than into the descending aorta (10.3 vs 17.9 sec; P < .001) and the distal IVC (vs 15.6 sec; P < .001). With dilution with albumin instead of phosphate-buffered saline, tachypnea was delayed and suppressed (9.9 vs 13.0 sec; P < .001, 24.1 vs 17.0 breaths/min; P = .031).ConclusionsA low albumin level is a risk factor for TSM, which could be caused by the effect of gadoxetate disodium on the head and neck region.

Anxiety-like behavior induced by allergen is associated with decreased irregularity of breathing pattern in rats

Allergic rhinitis (AR) is a chronic inflammatory disorder associated with a high prevalence of anxiety symptoms and respiratory disorders that adversely affect the quality of life. Studies have shown that allergen exposure induces anxiety-like behaviors. On the other hand, stress impairs the breathing pattern. However, the effect of stress on respiration and the relationship between anxiety-like behavior and stress-induced changes in breathing pattern has not been evaluated in AR. We assessed the impact of ovalbumin (OVA)-induced anxiety-like behaviors on stress-induced breathing pattern changes. Our findings showed that the allergic rhinitis induced by OVA challenge in sensitized rats induces anxiety-like behavior. Also, we found that stress decreases respiratory irregularity and increases respiratory variability, as well as the synchronization between IBI and RV time-series in AR animals. Moreover, in AR animals, we found a significant positive correlation between anxiety-like behavior and respiratory irregularity under non-stress conditions. Besides, a significant negative correlation was observed under stress conditions. The findings showed that anxiety-related behaviors may contribute to respiratory impairments under stress conditions in AR.

Evidence of an active Cushing reflex in a preterm neonate with hyaline membrane disease: a case report

BackgroundThe Cushing reflex does not appear to have been described in preterm neonates. This case report shows the presence of an active Cushing reflex in a 32-week preterm neonate with hyaline membrane disease.Case presentationThe 1.94 kg Caucasian infant was delivered by caesarean section following concerns about possible maternal infection and fetal compromise. Chest X-ray showed mild-to-moderate hyaline membrane disease and treatment was initiated with supplemental oxygen and nasal continuous positive airway pressure. It is probable that a pneumothorax occurred at 5–6 hours of age, with progression during the day. Interstitial air, pneumomediastinum, and tension pneumothorax were diagnosed on subsequent X-ray, and ultrasound of the brain showed a grade IV intraventricular hemorrhage. A review of the nurses’ recordings of heart rate, blood pressure, and respiratory rate showed a progressive increase in blood pressure accompanied by slowing of the heart rate and irregular respiration. These are features of the Cushing reflex that is elicited in response to raised intracranial pressure.ConclusionWhile well-described in older children and adults, in neonates the Cushing reflex has mainly been described in animal experiments and infants who have developed hydrocephalus. It is likely that in this case, the reflex was elicited as a result of a progressive increase in intracranial pressure due to the combination of elevated intrathoracic pressure, obstructed venous return from the brain, and concurrent intraventricular hemorrhage.

Intracraniaal infectieus aneurysma: belang van vroegtijdige diagnose

Intracranial aneurysm: importance of early detection A 45-year old woman presented at the emergency department with a decreased level of consciousness. She was under treatment for acute myeloid leukemia. An MRI scan of the brain showed diffuse vasoconstriction of the intracranial vasculature, suggestive for vasculitis. Aspergillus fumigatus was discovered in the cerebrospinal fluid (CSF), for which antimycotic treatment was initiated. Because of further neurological decline (acute decreased consciousness, unilateral gaze impairment and irregular obstructive respiration pattern) a CT scan was performed which showed diffuse subarachnoid and intraventricular hemorrhaging. CT-angiography showed an aneurysm at the left posterior inferior cerebellar artery. Because of the severe clinical condition of the patient, there was no indication for invasive therapy.

Evaluation of thoracic surface motion during the free breathing and deep inspiration breath hold methods.

The aim of this study was to evaluate thoracic surface motion from chest wall expansion during free breathing (FB) and deep inspiration breath hold (DIBH) methods, measured with and without 4-dimensional computed tomography (4D-CT) simulation, using equipment developed in-house. The respiratory amplitude and chest wall expansion were evaluated at 5 levels of the thorax, (the sterno-clavicular joint (SCJ), the second level, the intermammary line (IML), the fourth level and the caudal end of the xiphoid process (XP)) using radiopaque wires and potentiometers, with a CT scan simultaneously. This study included 25 examinees (10 volunteers performed FB, 10 volunteers performed DIBH and 5 patients performed FB). For low and irregular respiration, coaching was used, and its impact was evaluated for both breathing methods, FB and DIBH. The breathing amplitude performed with FB between volunteers and patients was not detectable at the SCJ; increasing to the abdomen, 3 mm vs 2 mm (p = 0.326) at the second level; 6 mm vs 4 mm (p = 0.042) at the IML; 10 mm vs 8 mm (p < 0.01) at the fourth level; and 23 mm vs 19 mm (p < 0.001) at the XP. Contrary to the DIBH, where breathing amplitude was greater at 2 first levels 18 mm (SCJ) and 20 mm (second level), decreasing to the abdomen, 14 mm (IML); 11 mm (fourth level); and 10 mm (XP). Chest wall expansion was not detected at the SCJ, while at other levels measured from 1 to 7 mm. Coaching was improve breathing amplitude, for both methods, FB (3 mm) and DIBH (5 mm). The location of amplification is different depending on the breathing method and the in-house phantom was useful to check the amplification level.