Single Breath Research Articles

Advances in Mid-Infrared Spectroscopy-Based Sensing Techniques for Exhaled Breath Diagnostics.

Human exhaled breath consists of more than 3000 volatile organic compounds, many of which are relevant biomarkers for various diseases. Although gas chromatography has been the gold standard for volatile organic compound (VOC) detection in exhaled breath, recent developments in mid-infrared (MIR) laser spectroscopy have led to the promise of compact point-of-care (POC) optical instruments enabling even single breath diagnostics. In this review, we discuss the evolution of MIR sensing technologies with a special focus on photoacoustic spectroscopy, and its application in exhaled breath biomarker detection. While mid-infrared point-of-care instrumentation promises high sensitivity and inherent molecular selectivity, the lack of standardization of the various techniques has to be overcome for translating these techniques into more widespread real-time clinical use.

Copper Oxide Thin Films for Sub-Ppm Acetone Detection Obtained By Glancing Angle Magnetron Sputtering Deposition

IntroductionThe number of gas-sensing applications increases year by year including industrial application as well as new approaches such as medical diagnostics, where gas sensors are used for measurement of volatile organic compounds present in the exhaled human breath. Over 3500 various VOCs have been already detected in the exhaled human breath, and a single breath consists of 500 various VOCs [1]. Apart from the conventional breath alcohol detectors, the novel applications appeared such as the detection of biomarkers [2]. One of the promising compounds that can be used as a biomarker is acetone, which is considered to be the biomarker of diabetes since people with diabetes tend to have higher acetone detection that healthy people [3,4]. The exhaled acetone is usually in the range of 0.2 - 0.8 ppm and over 2.5 ppm for people without and with diabetes, respectively. In order to measure such low, sub-ppm, concentrations, laboratory systems are applied including GC-MS [5], PTR-MS [6], and recently e-noses [7] as well as single sensors [8].In this paper, the investigation results on the copper oxide (CuO) deposited by utilization of magnetron sputtering technology with glancing angle technique are presented, where CuO was deposited at various parameters such as deposition angle, argon/oxygen ratio. The responses to various sub-ppm acetone concentrations are presented.CuO depositionThe gas-sensing applications of CuO have been previously confirmed and described [9]. Here, the CuO thin films were deposited by the UHV magnetron sputtering system from Kurt J. Lesker with a glancing angle deposition technique realized by utilization of a commercial ECR manipulator, which allows us to change the deposition angle, substrate rotation, and it has integrated heater that can be heated up to 850oC. The base vacuum pressure and deposition vacuum pressure were 0.001 Pa and 0.3 Pa, respectively. The temperature was fixed at 200oC, the power at 100W, the argon/oxygen ratios were 33%, 50%, 66%, 80% and 100% (pure oxygen without argon). After deposition, the samples were annealed at 400oC for 4 hours in the air. Gas-sensing measurements The developed sensors were tested in the dedicated measurement setup based on the quartz-tube oven with gas-dosing lines, where various target gas concentrations are obtained by utilization of mass flow controllers 1179B (MKS Instruments, USA) and acetone canisters with 5 ppm of acetone (Air Products, UK). The gas sensor response (S) was defined as resistance ratio S=(Rgas-Rair)/Rair, where Rgas and Rair are electrical resistances in gas and air, respectively. Results and Conclusions The sensors have been measured under exposure to acetone in the 0.25–2.5 ppm range, which covers the exhaled acetone range. The results have confirmed the influence of the glancing angle deposition for gas detection, in this case for acetone detection. The highest responses have been obtained for samples deposited at 85o (Fig.1b), however, the SEM verification will be carried out to compare the morphology and nanorods distribution. Moreover, the deposition system allows us to deposit the copper oxides at various argon/oxygen concentrations including deposition in pure oxygen. The results presented in Fig.1a shows, that the highest responses have been obtained for samples deposited at 20%/80% Ar/O2 ratio. It has been underlined, that the samples were annealed after deposition and preheated for 4h at 300oC, 350oC, and 400oC before the measurements. Further investigations are focused on choosing the optimal deposition conditions for acetone-sensors as well as long-term stability tests are performing.Fig.1. The sensors’ responses under exposure to acetone in the 0.25–2.5 ppm range at various operating temperatures for gas-sensing layer deposited at various (a) oxygen concentrations; (b) deposition angles. Acknowledgments This research was funded by the National Science Centre, Poland 2017/26/D/ST7/00355.

Feasibility of wide detector three-pass arterial phase liver CT in patients with cirrhosis: timing of hyperenhancing lesion peak conspicuity.

To evaluate feasibility of a wide detector liver CT protocol with three acquisitions in the hepatic arterial phase. Forty-one patients with cirrhosis prospectively underwent a wide detector axial liver CT protocol. Three 16cm axial liver acquisitions were obtained during a single breath hold at peak aortic enhancement plus 10, 20, and 25s. Two readers working separately scored overall exam quality, identified hyperenhancing lesions, and subjectively scored and ranked relative lesion conspicuity. Objective lesion enhancement was measured and CNR calculated. Data were analyzed using a generalized linear models and Tukey's post hoc testing. Seventy-one hyperenhancing lesions were identified with average size of 1.8cm (range 0.4-9.6cm). The two readers separately identified 60 and 54 lesions on the 10s arterial acquisition, 70 and 67 on the 20s, and 52 and 51 on the 25s. The readers determined all exams had diagnostic image quality. Subjective ranking of lesion conspicuity was greatest at 20s in 62% of lesions but was greatest at 10 or 25s in 38%. CNR was highest at 20s in 58% of lesions but was highest at 10 or 25s in 42%. Overall, there was no significant difference in mean CNR between the three arterial acquisitions. A wide detector axial liver CT protocol with three acquisitions in the hepatic arterial phase is technologically feasible and results in diagnostic image quality. With this protocol, peak subjective and objective hyperenhancing lesion conspicuity may be earlier or later than 20s in up to 40% of lesions.

Simultaneous multi-slice T1 mapping using MOLLI with blipped CAIPIRINHA bSSFP

BackgroundThis study evaluates the possibility for replacing conventional 3 slices, 3 breath-holds MOLLI cardiac T1 mapping with single breath-hold 3 simultaneous multi-slice (SMS3) T1 mapping using blipped-CAIPIRINHA SMS-bSSFP MOLLI sequence. As a major drawback, SMS-bSSFP presents unique artefacts arising from side-lobe slice excitations that are explained by imperfect RF modulation rendering and bSSFP low flip angle enhancement. Amplitude-only RF modulation (AM) is proposed to reduce these artefacts in SMS-MOLLI compared to conventional Wong multi-band RF modulation (WM). Materials and methodsPhantoms and ten healthy volunteers were imaged at 1.5 T using a modified blipped-CAIPIRINHA SMS-bSSFP MOLLI sequence with 3 simultaneous slices. WM-SMS3 and AM-SMS3 were compared to conventional single-slice (SMS1) MOLLI. First, SNR degradation and T1 accuracy were measured in phantoms. Second, artefacts from side-lobe excitations were evaluated in a phantom designed to reproduce fat presence near the heart. Third, the occurrence of these artefacts was observed in volunteers, and their impact on T1 quantification was compared between WM-SMS3 and AM-SMS3 with conventional MOLLI as a reference. ResultsIn the phantom, larger slice gaps and slice thicknesses yielded higher SNR. There was no significant difference of T1 values between conventional MOLLI and SMS3-MOLLI (both WM and AM). Positive banding artefacts were identified from fat neighbouring the targeted FOV due to side-lobe excitations from WM and the unique bSSFP signal profile. AM RF pulses reduced these artefacts by 38%.In healthy volunteers, AM-SMS3-MOLLI showed similar artefact reduction compared to WM-SMS3-MOLLI (3 ± 2 vs 5 ± 3 corrupted LV segments out of 16). In-vivo native T1 values obtained from conventional MOLLI and AM-SMS3-MOLLI were equivalent in LV myocardium (SMS1-T1 = 935.5 ± 36.1 ms; AM-SMS3-T1 = 933.8 ± 50.2 ms; P = 0.436) and LV blood pool (SMS1-T1 = 1475.4 ± 35.9 ms; AM-SMS3-T1 = 1452.5 ± 70.3 ms; P = 0.515). Identically, no differences were found between SMS1 and SMS3 postcontrast T1 values in the myocardium (SMS1-T1 = 556.0 ± 19.7 ms; SMS3-T1 = 521.3 ± 28.1 ms; P = 0.626) and the blood (SMS1-T1 = 478 ± 65.1 ms; AM-SMS3-T1 = 447.8 ± 81.5; P = 0.085). ConclusionsCompared to WM RF modulation, AM SMS-bSSFP MOLLI was able to reduce side-lobe artefacts considerably, providing promising results to image the three levels of the heart in a single breath hold. However, few artefacts remained even using AM-SMS-bSSFP due to residual RF imperfections. The proposed blipped-CAIPIRINHA MOLLI T1 mapping sequence provides accurate in vivo T1 quantification in line with those obtained with a single slice acquisition.

Efficacy of breathing retraining program on bedside assessment of pulmonary function

Breathing retraining alters respiratory muscle recruitment and improves respiratory muscle performance. However, the effectiveness of Pursed Lip Breathing in reducing dyspnoea is controversial. The aims of this study are to determine if breathing retraining is influencing the Single Breath Count performed by dyspneic subjects and to assess the correlation between Single breath Count Test and Snider match test as the standard measures of bedside pulmonary function test in patients with dyspnoea. 100 Patients with dyspnoea were assessed in the baseline with snider match test and they were asked to perform a single breath count. 5 times weekly and for 4 weeks, the participants have been practicing Breathing Retraining. Pursed lip breathing (PLB) and diaphragmatic breathing (DB) are breathing retraining strategies to subjects with dyspnoea; Single Breath Count was measured by asking patients to take a deep breath and count as far as possible in their normal speaking voice without taking another breath. Counting was timed to a metronome set at 2 counts per second. Snider match test was conducted by blowing the matches at increasing the test distance from 3, 6, 9 inches. The result of this study will determine whether breathing retraining is safe and beneficial for people with dyspnoea.

Cough Reflex Sensitivity in Asthmatic Children.

New knowledge about the neural aspects of cough has revealed a complex network of pathways that initiate cough. The effect of inflammation on cough neural processing occurs at multiple peripheral and central sites within the nervous system. Evidence exists that direct or indirect neuroimmune interaction induces a complex response, which can be altered by mediators released by the sensory or parasympathetic neurons and vice versa. The aim of this study was to clarify changes of cough reflex sensitivity - the activity of airway afferent nerve endings - in asthmatic children.25 children with asthma and 15 controls were submitted to cough reflex sensitivity measurement - capsaicin aerosol in doubling concentrations (from 0.61 to 1250 µmol/l) was inhaled by a single breath method. Concentrations of capsaicin causing two (C2) and five coughs (C5) were reported. Asthmatic children' (11 boys and 14 girls, mean age 9 ± 1 yrs) cough reflex sensitivity (geometric mean, with the 95 % CI) for C2 was 4.25 (2.25-8.03) µmol/l vs. control C2 (6 boys and 9 girls, mean age 8 ± 1 yrs) was 10.61 (5.28-21.32) µmol/l (p=0.024). Asthmatic children' C5 was 100.27 (49.30-203.93) µmol/l vs. control C5 56.53 (19.69-162.35) µmol/l (p=0.348). There was a statistically significant decrease of C2 (cough threshold) in the asthmatic patients relative to controls (p-value for the two-sample t-test of log(C2) for the one-sided alternative, p-value = 0.024). The 95 % confidence interval for the difference of the mean C2 in asthma vs. control, [1.004, 6.207]. For C5, the difference was not statistically significant (p-value = 0.348). There was a statistically significant decrease of cough reflex sensitivity (the activity of airway afferent nerve endings) - C2 value in the asthmatic children relative to controls.

T1ρ magnetic resonance fingerprinting.

T1ρ relaxation imaging is a quantitative imaging technique that has been used to assess cartilage integrity, liver fibrosis, tumors, cardiac infarction, and Alzheimer's disease. T1 , T2 , and T1ρ relaxation time constants have each demonstrated different degrees of sensitivity to several markers of fibrosis and inflammation, allowing for a potential multi-parametric approach to tissue quantification. Traditional magnetic resonance fingerprinting (MRF) has been shown to provide quick, quantitative mapping of T1 and T2 relaxation time constants. In this study, T1ρ relaxation is added to the MRF framework using spin lock preparations. An MRF sequence involving an RF-spoiled sequence with TR , flip angle, T1ρ , and T2 preparation variation is described. The sequence is then calibrated against conventional T1 , T2 , and T1ρ relaxation mapping techniques in agar phantoms and the abdomens of four healthy volunteers. Strong intraclass correlation coefficients (ICC > 0.9) were found between conventional and MRF sequences in phantoms and also in healthy volunteers (ICC > 0.8). The highest ICC correlation values were seen in T1 , followed by T1ρ and then T2 . In this study, T1ρ relaxation has been incorporated into the MRF framework by using spin lock preparations, while still fitting for T1 and T2 relaxation time constants. The acquisition of these parameters within a single breath hold in the abdomen alleviates the issues of movement between breath holds in conventional techniques.

Restrictive spirometric pattern and true pulmonary restriction in a general population sample aged 50 - 64 years

BackgroundThere is low diagnostic accuracy of the proxy restrictive spirometric pattern (RSP) to identify true pulmonary restriction. This knowledge is based on patients referred for spirometry and total lung volume determination by plethysmograpy, single breath nitrogen washout technique or gas dilution and selected controls. There is, however, a lack of data from general populations analyzing whether RSP is a valid proxy for true pulmonary restriction. We have validated RSP in relation to true pulmonary restriction in a general population where we have access to measurements of total lung capacity (TLC) and spirometry.MethodsThe data was from the Swedish CArdioPulmonary bioImage Study (SCAPIS Pilot), a general population-based study, comprising 983 adults aged 50–64. All subjects answered a respiratory questionnaire. Forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) were obtained before and after bronchodilation. TLC and residual volume (RV) was recorded using a body plethysmograph. All lung function values are generally expressed as percent predicted (% predicted) or in relation to lower limits of normal (LLN). True pulmonary restriction was defined as TLC < LLN5 defined as a Z score < − 1.645, i e the fifth percentile. RSP was defined as FEV1/FVC ≥ LLN and FVC < LLN after bronchodilation. Specificity, sensitivity, positive and negative likelihood ratios were calculated, and 95% confidence intervals (CIs) were calculated.ResultsThe prevalence of true pulmonary restriction was 5.4%, and the prevalence of RSP was 3.4%. The sensitivity of RSP to identify true pulmonary restriction was 0.34 (0.20–0.46), the corresponding specificity was 0.98 (0.97–0.99), and the positive likelihood ratio was 21.1 (11.3–39.4) and the negative likelihood ratio was 0.67 (0.55–0.81).ConclusionsRSP has low accuracy for identifying true pulmonary restriction. The results support previous observations that RSP is useful for ruling out true pulmonary restriction.

Role of Inpatient Pulmonary Rehabilitation Program in Acute Exacerbation of Chronic Obstructive Pulmonary Disease Patients: A Case Series

Chronic Obstructive Pulmonary Disease (COPD) defined as a chronic inflammatory lung disease that causes airflow obstruction and limitation of the lungs that primarily affects the airway and lung parenchyma. Pulmonary rehabilitation (PR) in COPD have been shown improvement of respiratory capacity, exercise capacity, self-efficacy, quality of life, and reduce COPD-related hospital admission. The purpose of postural drainage, manual technique, and cough control is to drain the excessive sputum, while breathing control with pursed-lip breathing and breathing exercise with deep breathing exercise and chest expansion exercise are to improve the respiratory capacity and control. The purpose of this study was to investigate the feasibility and outcome of PR in patients with Acute Exacerbation (AE) of COPD. This case report describes 4 patients with of AE of COPD who received PR. The inpatient PR program was 5 consecutive days twice daily of 3 times repetition cough control, 2 sets of 6 repetition pursed lip breathing, 2 sets of 6 repetition deep breathing exercise, postural drainage, and manual clapping. The postural drainage and the manual technique were given according to the chest x-ray result. The result of 5 days PR was: improvement of clean airway, SOB, incentive spirometer, chest expansion, and single breath count test in all subjects. Our findings demonstrate that early inpatient PR in COPD AE is safe, significantly effective and beneficial by improving many aspects of respiratory function

The Effect of a five-Day Educational Program for Children with Asthma on Airway inflammation: A two-year study

The aim of this study was to investigate the effectiveness of a 5 day educational program in children with asthma on airway inflammation as measured by FeNO during 2 consecutive years. Ninety-four children with asthma were enrolled in Camp Wheez. Written consent was obtained for each participant. Children were educated on the early signs of asthma, identifying triggers and the use of controller medications. The curriculum was provided by the Asthma Camp consortium of the AAAAI. The NIOX Vero was used as a 6 to10 second, single breath, incentive quantitative measurement. We measured FeNO on day one (baseline) and day 5 (end of camp), 2018 and 2019. Ninety-four children were enrolled during the 5 day asthma camp 2018 and 2019. The average baseline FeNO was 36.3 ppb, compared to an average of 33.1 ppb on day 5. The average FeNO levels were the same at day 1 and day 5 in campers with a low (<20ppb) and intermediate FeNO (20-35 ppb.) However, in the 36 campers who had a high baseline FeNO >35 ppb there was a significant improvement in FeNO from an average 75 ppb down to 67 ppb. There was a 10% improvement overall at the end of camp. None of the campers were informed on their baseline levels nor received individual coaching. This 2 year study demonstrated the effectiveness of a 5-day asthma education program on 94 children with asthma. Our results showed a significant improvement in FeNo with a 10% improvement (p=.001) at the conclusion of asthma education.

Serial single breath count is a reliable tool for monitoring respiratory functions in Guillain-Barré Syndrome

In this study, we correlate single breath count (SBC) with arterial blood gas (ABG) parameters to derive a cutoff point for intubation and mechanical ventilation (MV) in Guillain-Barré Syndrome (GBS). Ninety-four GBS patients underwent serial SBC at 2 Hz using an audio program. ABG was done at admission, and repeated if SBC declined. The patients were intubated based on “the modified intubation criteria” as follows (a + b or c): (a) hypoxia (PaO2 < 60 mm of Hg on ventimask); (b) hypercarbia (PaCO2 > 50 mm of Hg); (c) acidosis (pH < 7.3). The primary outcome was the absolute SBC at which patients had ABG alteration needing intubation.All the patients maintained a desired ABG without respiratory distress till SBC 7. At SBC 5, need for MV could be predicted with a sensitivity of 90.6% and specificity of 95.2%. Admission SBC cut-off of 13 and relative delta SBC at 24 h cut-off of > 20% had a negative predictive value of 88.5% (95% CI 77.0%–96.0%) and 80.8% (95% CI 60.7%–93.4%) respectively for ruling out need of MV.SBC is a useful non-invasive measure for monitoring respiratory function and guiding ABG analysis. Till SBC 7, repeated ABG may be avoided in GBS.

Reliability of single breath hold three-dimensional cine kat-ARC for the assessment of biventricular dimensions and function

PurposeTo assess the accuracy and reproducibility of 3D-cine k-adaptative-t-autocalibrating reconstruction for cartesian sampling (3D cine kat-ARC) for quantification of biventricular volumes, ejection fraction and LV mass in clinical practice. Method74 patients underwent cardiac magnetic resonance for clinical indications. In the whole population 3D cine kat-ARC and 2D cine bSSFP images were acquired on short axis view. Subsequently, the population was divided in three subgroups (dilated, hypetrophic, other phenotypes).Two experienced observers performed analysis of volumes, biventricular function and left ventricular mass in the overall population and subgroups using an off-line workstation.Statistical analysis was performed using Student's t-test, linear regression and Bland-Altman plot, correlation coefficient η2 and the intraclass correlation coefficient (ICC). A cut-off value of p < 0.05 was considered statistically significant. ResultsBiventricular volumes, function and left ventricular mass evaluated with 3D cine kat-ARC sequences did not show any significant difference compared to 2D bSSFP sequences in the overall population (p > 0.05). Bland-Altman analysis showed limited bias and narrow limits of the agreement for all measurements in overall population. Subgroup analysis showed a statistically significant difference (p = 0.04) for left ventricular ejection fraction (LVEF) in patients with a dilated phenotype; showing a minimum overestimation tendency for 3D cine kat ARC (2D cine bSSFP LVEF = 46.44 ± 15.83% vs 3D cine kat-ARC LVEF = 48.36 ± 16.50 %). Conclusions3D cine kat-ARC 3D sequences allow an accurate evaluation of biventricular volumes and function in a single breath hold.

A Preliminary Numerical Investigation of Airborne Droplet Dispersion in Aircraft Cabins

The emergence of the novel coronavirus has led to a global pandemic which has led to the airline industry facing severe losses. For air travel to recover, airlines need to ensure safe air travel. In this paper, the authors have modelled droplet dispersion after a single breath from an index patient. Computational Fluid Dynamics (CFD) simulations are conducted using the k-w SST turbulence model in ANSYS Fluent. The authors have taken into consideration several parameters such as the size of the mouth opening, the velocity of the cabin air as well as the number of droplets being exhaled by the index patient to ensure a realistic simulation. Preliminary results indicate that after a duration of 20s, droplets from the index patient disperse within a 10 m2 cabin area. About 75% of the droplets are found the disperse for up to 2m axially behind the index patient. This could possess an enhanced risk to passengers sitting behind the index patient. Ultimately, this paper provides an insight into the potential of CFD to visualise droplet dispersal and give impetus to ensuring necessary mitigating measures can be taken to reduce the risk of infection through droplet dispersal.

Randomized double-blind trial comparing effects of low-flow vs high-flow anesthesia on postoperative lung functions using respirometer.

Background and Aims:Modern anesthetic practice utilizes low-flow anesthesia with evolving evidence on its pulmonary effects. Studies comparing measurement of vital capacity and inspiratory reserve volume using respirometer in both low-flow and high-flow anesthesia are sparse. We evaluated the effects of low-flow and high-flow anesthesia on postoperative pulmonary functions using respirometer.Material and Methods:This was a prospective randomized double blind study wherein One hundred and ten patients undergoing peripheral surgeries under general anesthesia were allocated into two groups Group I- Low-flow anesthesia with O2 + N2O + Sevoflurane (0.5L + 0.5L + 3.5%) and Group II- High-flow anesthesia with O2 + N2O + Sevoflurane (2L + 2L + 2%). The difference in vital capacity (VC), inspiratory reserve volume (IRV), and peak expiratory flow rates (PEFR) from the preoperative period were compared in both the groups postoperatively.Results:The difference in VC, IRV, and PEFR measured in both the groups between the preoperative and postoperative period were found to be similar and statistically insignificant (P - 0.173, 1.00 and 0.213 respectively). The difference in single breath count (SBC), breath holding time (BHT), and respiratory rates (RR) were also similar in both the groups (P – 0.101, 0.698, and 0.467) respectively.Conclusions:The pulmonary effects of low-flow anesthesia are comparable with the high-flow ones in patients undergoing elective surgeries under general anesthesia.

Lack of association between six-minute walk distance and pulmonary artery pressure in patients with systemic sclerosis and cardiopulmonary symptoms.

The six-minute walk test (6MWT) is a non-invasive test used to assess cardiopulmonary performance. The aim of this study was to evaluate the performance of 6MWT in predicting pulmonary artery hypertension (PAH) and interstitial lung disease in patients with systemic sclerosis (SSc) and cardiopulmonary symptoms. Sixty-three patients with SSc who had dyspnea, cough, chest pain and syncope underwent 6MWT, high-resolution computed tomography (HRCT), spirometry, body plethysmography and single breath carbon monoxide diffusion measurement. There were no significant differences in mean 6MWD between patients with diffuse SSc compared with limited disease, patients with no parenchymal involvement compared with patients with parenchymal involvement <20% and≥20% in HRCT, and patients with PAP ≥25 mm Hg compared with patents with PAP <25 mm Hg. No significant relationship was found between 6MWD and age, mean PAP, forced expiratory volume, forced vital capacity and diffusing capacity of the lungs for carbon monoxide. The present study showed that in patients with SSc and cardiopulmonary symptoms, 6MVT does not help to predict PAH and parenchymal lung involvement.

Lung: Another Victim of the Silent killer Diabetes- A Cross-sectional Study

Introduction: Diabetes is a multisystem disorder with well known complications involving various organs in the body. The presence of abundant connective tissue and microvasculature raises the possibility that lung may also be affected in diabetes. Aim: To evaluate the pulmonary function parameters in patients with diabetes mellitus and to determine their correlation with glycaemic control, duration of diabetes and other microvascular complications. Materials and Methods: This is a cross-sectional study done between September 2018 and March 2019. A total of 300 type 2 diabetic patients, aged 30-70 years, with duration of diabetes more than 1 year, were included in the study. Thorough history was taken regarding the duration of diabetes and symptoms of the complications. All of them were evaluated for diabetic microangiopathies: nephropathy (by 24 hour urinary protein excretion), retinopathy (by direct ophthalmoscopy) and neuropathy (by clinical examination). Glycosylated Haemoglobin (HbA1c) was measured as an indicator of glycaemic control. Spirometry and single breath diffusion capacity for carbon monoxide were performed on all the subjects. Pulmonary Function Test (PFT) parameters of each subject were compared with the normal values. Unpaired t-test and one-way analysis of variance (ANOVA) were used. Correlation and regression studies were used to find out the strength of association between Diffusing Capacity of the Lungs for Carbon Monoxide (DLCO) and the following: the duration of disease, HbA1c and presence of other microvascular complications. Results: Pulmonary function parameters like Forced Expiratory Volume in first second (FEV1), Forced Vital Capacity (FVC), Peak Expiratory Forced Rate (PEFR) and DLCO were below the normal values in 53% of diabetic patients included in the study. Majority of them had a restrictive ventilation pattern. The diffusion capacity corrected for Alveolar Volume (VA) as measured by DLCO/VA was significantly reduced in those with longer duration of diabetes and in those with other microvascular complications. However, the poor lung functions had no correlation with the HbA1C values. Conclusion: This study demonstrated that lungs are indeed affected in patients with type 2 diabetes. The presence of extrapulmonary microangiopathy and duration of the disease may predict the incidence and the severity of the lung function abnormality.

Assessment of Conventional Autonomic Function Tests in Patients with Acute Intermittent Porphyria

Background and Aim: To assess the autonomic nerve functions in latent and manifest patients of acute intermittent porphyria. The aim of the present study was to study cardiovascular responses to autonomic nerve functions in patients of acute intermittent porphyria, we also tried to find out the relative sensitivity of the various tests employed to study cardiac dysautonomia in these cases. Methods: The study was carried out on thirty cases of acute intermittent porphyria to assess the cardiovascular reflexes. Twenty five healthy subjects closely matched for age and sex served as control. The cases were diagnosed by modified Watson Schwartz test, the cases of acute intermittent porphyria were divided into three groups. Results: The values of different autonomic nerve function tests were compared with control group and among the different groups of patients. The results were complied, compared and a conclusion was drawn. Immediate heart rate response to standing is more sensitive test than the Valsalva maneuver. Immediate heart rate response to standing is more sensitive and quite reliable which can easily be performed at bed side or even in outpatient departments, the test is simple and non–invasive. In our opinion, the test, beat to beat variation of heart rate to single deep breath is though easy to perform and more understandable, but lacks the sensitivity of other two tests. Conclusion: Significant cardiac dysautonomia is present in asymptomatic group, it is more marked in acute attack group. Immediate heart rate response to standing could be a more sensitive and reliable test in this dysfunction.

Generalized Linear Binning to Compare Hyperpolarized 129Xe Ventilation Maps Derived from 3D Radial Gas Exchange Versus Dedicated Multislice Gradient Echo MRI

Hyperpolarized 129Xe ventilation MRI is typically acquired using multislice fast gradient recalled echo (GRE), but interleaved 3D radial 129Xe gas transfer MRI now provides dissolved-phase and ventilation images from a single breath. To investigate whether these ventilation images provide equivalent quantitative metrics, we introduce generalized linear binning analysis. This study included 36 patients who had undergone both multislice GRE ventilation and 3D radial gas exchange imaging. Images were then quantified by linear binning to classify voxels into one of four clusters: ventilation defect percentage (VDP), Low-, Medium- or High-ventilation percentage (LVP, MVP, HVP). For 3D radial images, linear binning thresholds were generalized using a Box-Cox rescaled reference histogram. We compared the cluster populations from the two ventilation acquisitions both numerically and spatially. Interacquisition Bland-Altman limits of agreement for the clusters between 3D radial vs GRE were (-7% to 5%) for VDP, (-10% to 14%) for LVP, and (-8% to 8%) for HVP. While binning maps were qualitatively similar between acquisitions, their spatial overlap was modest for VDP (Dice = 0.5 ± 0.2), and relatively poor for LVP (0.3 ± 0.1) and HVP (0.2 ± 0.1). Both acquisitions yield reasonably concordant VDP and qualitatively similar maps. However, poor regional agreement (Dice) suggests that the two acquisitions cannot yet be used interchangeably. However, further improvements in 3D radial resolution and reconciliation of bias field correction may well obviate the need for a dedicated ventilation scan in many cases.

Evaluation of Pulmonary Function in Patient with Transfusion Dependent Beta Thalassemia with Severe Iron Overload

Background; Transfusion-dependent β-thalassemia (TDT) is a severe form of congenital anemia. Regular blood transfusion and continual administration of iron-chelators are conventional therapeutic strategies in TDT. Despite progressive advancements in developing various iron scavenging drugs, iron overload is still considered a challenging conundrum in these patients. Multiple organ dysfunctions result from the toxic effect of excess iron deposition in parenchymal tissues that cause high morbidity and mortality among TDT patients. The greatest affected tissues include endocrine glands, liver, heart, and kidneys. Aim of the study: To investigate pulmonary function of patients with TDT in relation to their iron overload. Patients and Methods: Pulmonary function tests were done for 10 Patient with TDT (table 1) in a well-equipped lung function unit in a tertiary care hospital by experienced respiratory technicians. An ideal test session was taken up following ATS/ERS recommendations. A proper grading system including acceptability and repeatability criteria was applied. Measurement of DLCO is done with a technique of single breath carbon monoxide (CO) uptake in the lung and lung volume is measured with gas dilution and body plethysmography. Chest x ray (CXR) was obtained in all patients. Pulmonary function test was classified according to the following categories based on ATS/ERS criteria and American medical association criteria (AMA); Normal: FEV1/FVC more than 70% FEV1, FVC, TLC, RV and DLCO normal (at least 80% predicted)Obstructive: FEV1/FVC less than 70% FEV1 and FVC (less than 80% predicted). TLC and RV either normal or elevated (at least 120% predicted). DLCO normal (at least 80% predicted)Restrictive: FEV1/FVC ratio (more than 70%) (1) FEV1, FVC, and TLC decreased (no more than 80% predicted) and a decrease in DLCO (no more than 80% predicted) or (2) TLC and RV decreased (no more than 80% predicted) with normal DLCO, FEV1, FVC, and FEV1/FVC, suggestive of low lung volumes, or (3) reduced TLC and DLCO.Mixed obstructive and restrictive: FEV1/FVC ratio reduced, suggestive of obstructive disease. TLC and RV reduced, suggestive of restrictive disease. DLCO normalIsolated low DLCO: DLCO decreased with normal FEV1, FVC, FEV1/FVC, TLC, and RV (As per AMA DLCO less than 75% were considered abnormal) Results: In our 10 TDT patients 9 had normal CXR. One patient had minimal patchy ground glass opacity. Six patients (60%) had abnormally low DLCO indicating some impairment at the level of alveolar capillary membrane. None of them had obstructive pattern. However 2 patients had some air trapping. DLCO, DLCO/Hb, DLCO/VA and RV were correlated negatively with LIC (fig 1) . PFTs (DLCO, RV, and TLC) were correlated negatively with the LIC. In addition, FEV1 and FVC were correlated negatively with ferritin level (r = -0.7 and -0.77 respectively, p &lt;0.01) (fig2). Discussion: we documented a significant alveolar capillary membrane dysfunction in a good number of asymptomatic patients with TDT. This dysfunction appears to increase with advance of age. Iron deposition in the lung parenchyma appears to be the etiology of this abnormality as supported by the significant negative correlations between PFT parameters on the one hand and LIC and ferritin level on the other hand. Conclusions: Substantial alveolar capillary membrane dysfunction occurs in a good number of asymptomatic patients with TDT which is correlated with the degree of iron overload. Further studies are required to confirm these abnormalities on a large scale. Disclosures No relevant conflicts of interest to declare.

BET 1: Efficacy of different techniques using a metered-dose inhaler with Spacer to relieve symptoms in children with acute asthma

A shortcut review was carried out to establish which inhaler with spacer technique provides the greatest improvement in symptoms in children with acute asthma. Four relevant papers were identified for...