Inspiratory Volume Research Articles

SEASONAL CHANGES OF EXTERNAL RESPIRATORY PARAMETERS IN SKIERS OF MASS CATEGORIES IN THE CONDITIONS OF RUSSIAN NORTH

The study results of lung volume seasonal changes in skiers of mass categories in the conditions of European North are presented. Respiratory system study was carried out in September, January, April and July in the same group of 38 men skiers aged 18-22 (middle age: 19,6 (19,2; 21,7)), born and permanently residing in Arkhangelsk (64°32'n.l., 40°32'e.l.) and Severodvinsk (64°34'n.l., 39°51'e.l.). Survey sample had experience in cross-country skiing for 3-5 years and 1-2 senior degree. Spirograph «Dinamit-С» (Complex КМ-АР-01) was used for pulmonary function test. Lung volume was esteemed: respiratory volume (RV), inspiratory (IRV) and expiratory (ERV) reserve volume, inspiratoty capacity (IC), lung capacity (LC), as well as indices of lung ventilation: respiratory rate (RR) and respiratory minute volume (RMV). It is stated that skiers have seasonal functional alternation in the external respiration system. Thus, LC maximum was in winter, LC minimum - in spring, with difference 1,21 l. RV minimum was in summer, maximum - in winter, with difference 0,58 l. IRV was maximum in autumn, ERV and IC - in winter. Not only statistic lung volumes indices, but their nature of communication change in seasonal dynamic in surveyed sportsmen skiers. Percentage ratio calculation from RV to LC showed that breathing in rest conditions skiers use from 17 % in autumn and summer to 21-23,5 % LC in winter and spring. Comparison of the results obtained in skiers and people not engaged in sport activities revealed that seasonal changes of lung volume in skiers are more evident.

Electromyography-Guided Botulinum Toxin Injection Into the Cricothyroid Muscles in Bilateral Vocal Fold Abductor Paralysis.

ObjectivesBilateral vocal fold abductor paralysis (BVFAP) both deteriorates quality of life and may cause life-threatening respiratory problems. The aim of this study was to reduce respiratory symptoms in BVFAP patients using cricothyroid (CT) botulinum toxin (BTX) injection.MethodsBefore and 2 weeks and 4 months after bilateral BTX injection into the CT muscles under electromyography; alterations in respiratory, acoustic, aerodynamic and quality of life parameters were evaluated in BVFAP patients with respiratory distress. For the respiratory evaluation modified Borg scale and spirometry, for the voice and aerodynamic evaluations Voice Handicap Index-30 (VHI-30), GRBAS, acoustic analysis (sound pressure level, F0, jitter%, shimmer%, noise-to-harmonic ratio) and maximum phonation time and for the quality of life assessment Short Form-36 (SF-36) form were used.ResultsAll patients were female with a mean age of 47±8.1 years. There was a mean time of 11.8±5.5 (minimum 2, maximum 23) months between BVFAP development and BTX injection. In all cases, other than one case with unknown aetiology, the cause of vocal fold paralysis was prior thyroid surgery. In total 18.6±3.1 units of BTX were applied to the CTs. In the preinjection period, and the 2nd week and 4th month after injection, the Borg dyspnea scale was 7.3/5.3/5.0, FIV1 (forced inspiratory volume in one second) was 1.7/1.7/1.8 L, peak expiratory flow (PEF) was 1.4/1.7/2.1 L/sec, maximum phonation time was 7.0/6.4/6.2 seconds and VHI-30 was 63.2/52.2/61.7 respectively. There was no significant alteration in acoustic analysis parameters. Many of the patients reported transient dysphagia within the first week. There were insignificant increases in SF-36 sub-scale values.ConclusionAfter BTX injection, improvements in the mean Borg score, PEF and FIV1 values and SF-36 sub-scale scores showed the restricted success of this approach. This modality may be kept in mind as a transient treatment option for patients refused persistent tracheotomy or ablative airway surgeries.

Quantifying unintended exposure to high tidal volumes from breath stacking dyssynchrony in ARDS: the BREATHE criteria.

Breath stacking dyssynchrony generates higher tidal volumes than intended, potentially increasing lung injury risk in acute respiratory distress syndrome (ARDS). Lack of validated criteria to quantify breath stacking dyssynchrony contributes to its under-recognition. This study evaluates performance of novel, objective criteria for quantifying breath stacking dyssynchrony (BREATHE criteria) compared to existing definitions and tests if neuromuscular blockade eliminates high-volume breath stacking dyssynchrony in ARDS. Airway flow and pressure were recorded continuously for up to 72h in 33 patients with ARDS receiving volume-preset assist-control ventilation. The flow-time waveform was integrated to calculate tidal volume breath-by-breath. The BREATHE criteria considered five domains in evaluating for breath stacking dyssynchrony: ventilator cycling, interval expiratory volume, cumulative inspiratory volume, expiratory time, and inspiratory time. The observed tidal volume of BREATHE stacked breaths was 11.3 (9.7-13.3)mL/kg predicted body weight, significantly higher than the preset volume [6.3 (6.0-6.8)mL/kg; p<0.001]. BREATHE identified more high-volume breaths (≥2mL/kg above intended volume) than the other existing objective criteria for breath stacking [27 (7-59) vs 19 (5-46) breaths/h; p<0.001]. Agreement between BREATHE and visual waveform inspection was high (raw agreement 96.4-98.1%; phi 0.80-0.92). Breath stacking dyssynchrony was near-completely eliminated during neuromuscular blockade [0 (0-1) breaths/h; p<0.001]. The BREATHE criteria provide an objective definition of breath stacking dyssynchrony emphasizing occult exposure to high tidal volumes. BREATHE identified high-volume breaths missed by other methods for quantifying this dyssynchrony. Neuromuscular blockade prevented breath stacking dyssynchrony, assuring provision of the intended lung-protective strategy.

ТЕОРЕТИЧЕСКИЕ И МЕТОДИЧЕСКИЕ АСПЕКТЫ БОДИПЛЕТИЗМОГРАФИИ И ЕЕ КЛИНИЧЕСКОЕ ПРИМЕНЕНИЕ

One of the methods to evaluate lung function is body plethysmography. Body plethysmography allows to measure indicators that cannot be obtained during spirometry, that is: total lung capacity (TLC), bronchial resistance (Raw), and functional residual capacity (FRC). FRC measured by body plethysmography reflects thoracic gas volume (TGV or VTG), and includes both ventilated and poorly ventilated volume. Plethysmographic measurements are based on the principle of the relationship between pressure and volume at constant temperature and fixed amount of gas. This principle states that the absolute pressure exerted by a given mass of an ideal gas is inversely proportional to the volume it occupies if the temperature and amount of gas remain unchanged within a closed system (Boyle-Mariotte Law). In body plethysmography, the following parameters: TGV, vital capacity (VC), expiratory reserve volume (ERV), tidal volume (TV), inspiratory reserve volume (IRV), inspiratory capacity (IC), Raw are obtained. TLC, residual volume (RV) and its share in total lung capacity can be calculated. Reduced TLC allows to diagnose restrictive disorders of pulmonary ventilation. The RV and its share in TLC increase together with airway obstruction indicates air trapping. The TGV increase together with airway obstruction indicates hyperinflation. In the analysis of lung volumes predictive values, which are calculated by the formulas recommended by ATS/ERS statement, are used. The results are expressed as a percentage of the predicted value. Thus, body plethysmography is an important addition to spirometry and image methods of research, allowing to assess the functional state of the lungs more objectively; it helps to conduct the differential diagnosis and control the course of the disease.

Intraspinal transplantation of subventricular zone-derived neural progenitor cells improves phrenic motor output after high cervical spinal cord injury

Following spinal cord injury (SCI), intraspinal transplantation of neural progenitor cells (NPCs) harvested from the forebrain sub-ventricular zone (SVZ) can improve locomotor outcomes. Cervical SCI often results in respiratory-related impairments, and here we used an established model cervical SCI (C2 hemisection, C2Hx) to confirm the feasibility of mid-cervical transplantation of SVZ-derived NPCs and the hypothesis that that this procedure would improve spontaneous respiratory motor recovery. NPCs were isolated from the SVZ of enhanced green fluorescent protein (GFP) expressing neonatal rats, and then intraspinally delivered immediately caudal to an acute C2Hx lesion in adult non-GFP rats. Whole body plethysmography conducted at 4 and 8wks post-transplant demonstrated increased inspiratory tidal volume in SVZ vs. sham transplants during hypoxic (P=0.003) or hypercapnic respiratory challenge (P=0.019). Phrenic nerve output was assessed at 8wks post-transplant; burst amplitude recorded ipsilateral to C2Hx was greater in SVZ vs. sham rats across a wide range of conditions (e.g., quiet breathing through maximal chemoreceptor stimulation; P<0.001). Stereological analyses at 8wks post–injury indicated survival of ~50% of transplanted NPCs with ~90% of cells distributed in ipsilateral white matter at or near the injection site. Peak inspiratory phrenic bursting after NPC transplant was positively correlated with the total number of surviving cells (P<0.001). Immunohistochemistry confirmed an astrocytic phenotype in a subset of the transplanted cells with no evidence for neuronal differentiation. We conclude that intraspinal transplantation of SVZ-derived NPCs can improve respiratory recovery following high cervical SCI.

Monitoring tidal volumes when using the Ventrain® emergency ventilator

The Ventrain® emergency ventilation device allows active inspiration and expiration through transtracheal catheters or the lumen of an airway exchange catheter. This single-use handheld device is manually operated and driven by an external pressurized oxygen source. The Ventrain® may be used to ventilate patients with acomplete or pending upper airway obstruction reducing the risk of barotrauma due to the possibility of active expiration. However tidal volumes (V T) applied and withdrawn with the Ventrain® can only be controlled by visual inspection of chest movements; V T monitoring is not provided. Excessive inspiratory volumes or air trapping due to insufficient expiration may remain clinically undetected until pulmonary trauma and/or cardio-respiratory deterioration occur. Active expiration itself carries the risk of overwhelming lung deflation with the formation of atelectasis. Thus, an inspiratory and expiratory tidal volume monitor is urgently required. The aim of this study was to evaluate efficacy and precision of the Florian respiratory function monitor (RFM) to monitor in- and expiratory V T administered by the Ventrain® emergency ventilation device through asmall cannula to the ASL5000 test lung (ASL). In an in-vitro setting the RFM was used with its neonatal flow sensor to monitor inspiratory and expiratory V T applied by the Ventrain® emergency ventilation device through a2mm internal diameter (ID) transtracheal catheter to the ASL. Driving flows of 6, 9, 12 and 15l min(-1) were chosen to vary tidal volumes at aconstant respiratory rate of 15min(-1) and an I:E ratio of 1:1. Experiments were repeated five times with two flow sensors. An initial set-up calibration run was performed to calculate abias correction factor for inspiratory and expiratory V T measured by the RFM. This bias correction factor was used to simulate acorrection of the in the RFM programmed linearization table. In asecond, identical setting the experiments were repeated five times with two flow sensors. V T measured by the adjusted RFM were compared with those obtained from the ASL5000 in this second run and the percentage differences were calculated. Bland Altman analysis was used to investigate the agreement of inspiratory or expiratory VT measured by both methods (ASL and RFM). Calculation of the mean of differences between both methods is given as bias and the 95 % agreement interval as precision. Tidal volumes measured by the ASL ranged from 140 to 675ml. The percentage correction factor was 16.27 % (2.60 %) during inspiration for V T ranged from 0 to 700ml and 11.51 % (2.56 %) during expiration for V T of 0 to 225ml, 7.41 % (2.94 %) for VT 226 to 325ml and 5.35 % (3.57 %) for TV e >325ml. Inspiratory and expiratory tidal volumes measured by the adjusted RFM demonstrated apercentage deviation (mean [SD]) of 2.59 % (1.86 %) during inspiration and 1.66 % (1.14 %) during expiration when compared with the ASL5000. Bias (precision) of the Bland Altman plot for the adjusted RFM is 2.05ml (23.20) during inspiration and 4.62ml (10.40) for expiration. The tested respiratory function monitor using hot-wire anemometer technology has the potential to monitor tidal volumes applied by the Ventrain®. With the software thus adapted, the RFM measures precise inspiratory and expiratory tidal volumes within common technical tolerance. This could help perform adequate patient ventilation with Ventrain® and reduce the potential risk of patient trauma.

Changes in uncuffed endotracheal tube leak during laparoscopic inguinal herniorrhaphy in children.

The present study was conducted to investigate changes in uncuffed endotracheal tube (ETT) leak during laparoscopic surgery. The study included 31 patients aged between 1 and 6years scheduled for elective laparoscopic inguinal herniorrhaphy. Inspiratory and expiratory tidal volumes (TVi and TVe) were measured during mechanical ventilation, and ETT leak was calculated using the formula-ETT leak=(TVi-TVe)/TVi×100(%), assessed at the following time-points-5min after the start of mechanical ventilation (T1, baseline), just before the start of surgery (T2), 5min after the induction of pneumoperitoneum with 15° Trendelenburg tilt (T3), and at the end of surgery (T4). Additionally, leak pressure was assessed after successful tracheal intubation (T0, baseline) at T2, T3 and T4. Uncuffed ETT leak significantly decreased at T3 compared with T1 (baseline). Leak pressure significantly increased at T3 and T4 compared with T0 (baseline). Further studies are needed in order to determine whether the results are universal and associated with clinically significant outcomes.

Overweight Is an Independent Risk Factor for Reduced Lung Volumes in Myotonic Dystrophy Type 1.

BackgroundIn this large observational study population of 105 myotonic dystrophy type 1 (DM1) patients, we investigate whether bodyweight is a contributor of total lung capacity (TLC) independent of the impaired inspiratory muscle strength.MethodsBody composition was assessed using the combination of body mass index (BMI) and fat-free mass index. Pulmonary function tests and respiratory muscle strength measurements were performed on the same day. Patients were stratified into normal (BMI < 25 kg/m2) and overweight (BMI ≥ 25 kg/m2) groups. Multiple linear regression was used to find significant contributors for TLC.ResultsOverweight was present in 59% of patients, and body composition was abnormal in almost all patients. In overweight patients, TLC was significantly (p = 2.40×10−3) decreased, compared with normal-weight patients, while inspiratory muscle strength was similar in both groups. The decrease in TLC in overweight patients was mainly due to a decrease in expiratory reserve volume (ERV) further illustrated by a highly significant (p = 1.33×10−10) correlation between BMI and ERV. Multiple linear regression showed that TLC can be predicted using only BMI and the forced inspiratory volume in 1 second, as these were the only significant contributors.ConclusionsThis study shows that, in DM1 patients, overweight further reduces lung volumes, as does impaired inspiratory muscle strength. Additionally, body composition is abnormal in almost all DM1 patients.

Functional Magnetic Stimulation of Inspiratory and Expiratory Muscles in Subjects With Tetraplegia

BackgroundRespiratory complications are major causes of morbidity and mortality in persons with a spinal cord injury, partly because of respiratory muscle paralysis. Earlier investigation has demonstrated that functional magnetic stimulation (FMS) can be used as a noninvasive technology for activating expiratory muscles, thus producing useful expiratory functions (simulated cough) in subjects with spinal cord injury. ObjectiveTo evaluate the effectiveness of FMS for conditioning inspiratory and expiratory muscles in persons with tetraplegia. DesignA prospective before and after trial. SettingFMS Laboratory, Louis Stokes Cleveland VA Medical Center, Cleveland, OH. ParticipantsSix persons with tetraplegia. MethodEach subject participated in a 6-week FMS protocol for conditioning the inspiratory and expiratory muscles. A magnetic stimulator was used with the center of a magnetic coil placed at the C7-T1 and T9-T10 spinous processes, respectively. Pulmonary function tests were performed before, during, and after the protocol. Main Outcome MeasurementsRespiratory variables included maximal inspiratory pressure (MIP), inspiratory reserve volume (IRV), peak inspiratory flow (PIF), maximal expiratory pressure (MEP), expiratory reserve volume (ERV), and peak expiratory flow (PEF). ResultsAfter 6 weeks of conditioning, the main outcome measurements (mean ± standard error) were as follows: MIP, 89.6 ± 7.3 cm H2O; IRV, 1.90 ± 0.34 L; PIF, 302.4 ± 36.3 L/min; MEP, 67.4 ± 11.1 cm H2O; ERV, 0.40 ± 0.06 L; and PEF, 372.4 ± 31.9 L/min. These values corresponded to 117%, 107%, 136%, 109%, 130%, and 124% of pre-FMS conditioning values, respectively. Significant improvements were observed in MIP (P = .022), PIF (P = .0001), and PEF (P = .0006), respectively. When FMS was discontinued for 4 weeks, these values showed decreases from their values at the end of the conditioning protocol, which suggests that continual FMS may be necessary to maintain improved respiratory functions. ConclusionFMS conditioning of the inspiratory and expiratory muscles improved voluntary inspiratory and expiratory functions. FMS may be a noninvasive technology for respiratory muscle training in persons with tetraplegia.

Common Mechanisms of Dyspnea in Chronic Interstitial and Obstructive Lung Disorders

The mechanisms underlying dyspnea in interstitial lung disease (ILD) and chronic obstructive pulmonary disease (COPD) are unknown. To examine whether the relationship between inspiratory neural drive to the diaphragm and exertional dyspnea intensity is different in ILD and COPD, given the marked differences in static respiratory mechanics between these conditions. We compared sensory-mechanical relationships in patients with ILD, patients with COPD, and healthy control subjects (n = 16 each) during incremental cycle exercise with diaphragmatic electromyography (EMGdi) and respiratory pressure measurements. In patients with mild to moderate ILD or COPD with similarly reduced inspiratory capacity, the peak oxygen uptake, work rate, and ventilation were lower (P < 0.05) than in healthy control subjects. EMGdi expressed as a percentage of the maximum (EMGdi/EMGdi,max), respiratory effort (esophageal pressure expressed as percentage of the maximum), and ventilation were higher (P < 0.05) at rest and during exercise in both patients with ILD and patients with COPD than in control subjects. Each of these measurements was similar in the ILD and COPD groups. A Vt inflection and critically reduced inspiratory reserve volume occurred at a lower (P < 0.05) ventilation in the ILD and COPD groups than in control subjects. Patients with ILD had greater diaphragmatic activity, whereas patients with COPD had greater expiratory muscle activity. The relationship between dyspnea intensity and EMGdi/EMGdi,max during exercise was similar in all three groups. In ILD and COPD, descriptors alluding to inspiratory difficulty were selected more frequently, with a greater disparity between EMGdi/EMGdi,max and Vt. Disease-specific differences in mechanics and respiratory muscle activity did not influence the key association between dyspnea intensity and inspiratory neural drive to the diaphragm.

Effective Bronchoscopic Lung Volume Reduction Accelerates Exercise Oxygen Uptake Kinetics in Emphysema

The impact of bronchoscopic lung volume reduction (BLVR) on physiologic responses to exercise in patients with advanced emphysema remains incompletely understood. We hypothesized that effective BLVR (e-BLVR), defined as a reduction in residual volume > 350 mL, would improve cardiovascular responses to exercise and accelerate oxygen uptake (Vo₂) kinetics. Thirty-one patients (FEV1, 36% ± 9% predicted; residual volume, 219% ± 57% predicted) underwent a constant intensity exercise test at 70% peak work rate to the limit of tolerance before and after treatment bronchoscopy (n = 24) or sham bronchoscopy (n = 7). Physiologic responses in patients who had e-BLVR (n = 16) were compared with control subjects (ineffective BLVR or sham bronchoscopy; n = 15). e-BLVR reduced residual volume (-1.1 ± 0.5 L, P = .001), improved lung diffusing capacity by 12% ± 13% (P = .001), and increased exercise tolerance by 181 ± 214 s (P = .004). Vo₂ kinetics were accelerated in the e-BLVR group but remained unchanged in control subjects (Δ mean response time, -20% ± 29% vs 1% ± 25%, P = .04). Acceleration of Vo₂ kinetics was associated with reductions in heart rate and oxygen pulse response half-times by 8% (84 ± 14 to 76 ± 15 s, P = .04) and 20% (49 ± 16 to 34 ± 16 s, P = .01), respectively. There were also increases in heart rate and oxygen pulse amplitudes during the cardiodynamic phase post e-BLVR. Faster Vo₂ kinetics in the e-BLVR group were significantly correlated with reductions in residual volume (r = 0.66, P = .005) and improvements in inspiratory reserve volume (r = 0.56, P = .024) and exercise tolerance (r = 0.63, P = .008). Lung deflation induced by e-BLVR accelerated exercise Vo₂ kinetics in patients with emphysema. This beneficial effect appears to be related mechanistically to an enhanced cardiovascular response to exercise, which may contribute to improved functional capacity.

Evaluation the effect of breathing filters on end-tidal carbon dioxide during inferior abdominal surgery in infants and changes of tidal volume and respiratory rate needs for preventing of increasing end-tidal carbon dioxide.

Background:The aim of this study was to prevent of increasing end-tidal carbon dioxide (ETCO2) with changing of vital capacity and respiratory rate when using of birthing filter in infants.Materials and Methods:In a randomized clinical trial study, ninety-four infant’ patients were studied in three groups. Basic values, such as peak inspiratory pressure, tidal volume, minute ventilation, respiratory rate, and partial pressure of ET CO2 (PETCO2) level had been evaluated after intubation, 10 min after intubation and 10 min after filter insertion. In the first group, patients only observed for changing in ETCO2 level. In the second and the third groups, respiratory rates and tidal volume had been increased retrospectively, until that ETCO2 ≤35 mmHg was received. We used ANOVA, Chi-square, and descriptive tests for data analysis. P < 0.05 was considered statistically significant.Results:Tidal volume 10 min after filter insertion was statistically higher in Group 3 (145.0 ± 26.3 ml) versus 129.3 ± 38.9 ml in Group 1 and 118.7 ± 20.8 ml in Group 2 (P = 0.02). Furthermore, respiratory rate at this time was statistically higher in Group 2 (25.82 ± 0.43) versus Groups 1 and 3 (21.05 ± 0.20 ml and 21.02 ± 0.60 ml, respectively) (P = 0.001). Minute volume and PETCO2 level were statistically significant between Group 1 and the other two groups after filter insertion (P = 0.01 and P = 0.00,1 respectively).Conclusion:With changing the vital capacity and respiratory rate we can control PETCO2 level ≤35 mmHg during using of birthing filters in infants. We recommend this instrument during anesthesia of infants.

Effects of manual hyperinflation in preterm newborns under mechanical ventilation

ObjectiveTo assess the effects of manual hyperinflation, performed with a manual resuscitator with and without the positive end-expiratory pressure valve, on the respiratory function of preterm newborns under mechanical ventilation.MethodsCross-sectional study of hemodynamically stable preterm newborns with gestational age of less than 32 weeks, under mechanical ventilation and dependent on it at 28 days of life. Manual hyperinflation was applied randomly, alternating the use or not of the positive end-expiratory pressure valve, followed by tracheal aspiration for ending the maneuver. For nominal data, the two-tailed Wilcoxon test was applied at the 5% significance level and 80% power.ResultsTwenty-eight preterm newborns, with an average birth weight of 1,005.71 ± 372.16g, an average gestational age of 28.90 ± 1.79 weeks, an average corrected age of 33.26 ± 1.78 weeks, and an average mechanical ventilation time of 29.5 (15 - 53) days, were studied. Increases in inspiratory and expiratory volumes occurred between time-points A5 (before the maneuver) and C1 (immediately after tracheal aspiration) in both the maneuver with the valve (p = 0.001 and p = 0.009) and without the valve (p = 0.026 and p = 0.001), respectively. There was also an increase in expiratory resistance between time-points A5 and C1 (p = 0.044).ConclusionLung volumes increased when performing the maneuver with and without the valve, with a significant difference in the first minute after aspiration. There was a significant difference in expiratory resistance between the time-points A5 (before the maneuver) and C1 (immediately after tracheal aspiration) in the first minute after aspiration within each maneuver.

Ventilatory demand and dynamic hyperinflation induced during ADL-based tests in Chronic Obstructive Pulmonary Disease patients.

ABSTRACTBackgroundAirflow limitation frequently leads to the interruption of activities of daily living (ADL) in patients with Chronic Obstructive Pulmonary Disease (COPD). These patients commonly show absence of ventilatory reserve, reduced inspiratory reserve volume, and dynamic hyperinflation (DH).ObjectiveTo investigate ventilatory response and DH induced by three ADL-based protocols in COPD patients and compare them to healthy subjects.MethodCross-sectional study. COPD group: 23 patients (65±6 years, FEV1 37.2±15.4%pred); control group: 14 healthy subjects (64±4 years) matched for age, sex, and body mass index. Both groups performed all three tests: Glittre-ADL test; an activity test that involved moving objects on a shelf (TSHELF); and a modified shelf protocol isolating activity with upper limbs (TSHELF-M). Ventilatory response and inspiratory capacity were evaluated.ResultsBaseline ventilatory variables were similar between groups (p>0.05). The ventilatory demand increased and the inspiratory capacity decreased significantly at the end of the tests in the COPD group. Ventilatory demand and DH were higher (p<0.05) in the TSHELF than in the TSHELF–M in the COPD group (p<0.05). There were no differences in DH between the three tests in the control group (p>0.05) and ventilatory demand increased at the end of the tests (p<0.05) but to a lower extent than the COPD group.ConclusionThe TSHELF induces similar ventilatory responses to the Glittre-ADL test in COPD patients with higher ventilatory demand and DH. In contrast, the ventilatory response was attenuated in the TSHELF-M, suggesting that squatting and bending down during the Glittre-ADL test could trigger significant ventilatory overload.

Effect of ongoing isometric handgrip exercise on the inspiratory and expiratory reserve volumes

Background: Chronic diseases such as hypertension and diabetes have shown improvement in disease condition on isotonic exercises. But the same can cause deterioration in the health of patients with asthma, heart failure, and chronic obstructive pulmonary disease. Therefore, in such individuals, isometric exercise can be given a try. Isometric exercise is known to activate the autonomic nervous system, especially the parasympathetic fibers and thus has a bearing on the functioning of respiratory system. Aims and Objectives: This study was undertaken with a purpose to find acute change in respiratory reserve during handgrip exercise. Materials and Methods: 50 young apparently healthy volunteers between the ages of 18 to 35 years were enrolled for the study. Different spirometry volumes and capacities including inspiratory reserve volume (IRV) and expiratory reserve volume (ERV) were recorded on MedSpiror (RMS, Chandigarh, India) at baseline and during sustained hand grip using a hand dynamometer. Statistical analysis was done using SPSS 17.0 on the data obtained. Result: This study showed that FVC was significantly reduced during handgrip exercise. FEV1, PEFR, FEF 25–75% and IRV decreased while FEV1/FVC and ERV increased but these changes were not significant statistically. Conclusion: The reserve capacity of the lung does not change significantly during isometric exercise.

Association of Waist Circumference with Pulmonary Function in Obesity

Obesity is a global health hazard and the prevalence of obesity is increasing. There is evidence that obesity, particularly abdominal obesity is negatively associated with pulmonary function. Obesity-related health risks are better explained by waist circumference (WC) than BMI as it provides information on fat distribution that cannot be obtained from BMI. We aimed to evaluate the association of WC with pulmonary function in adults with or without obesity. Pulmonary function was assessed by spirometry in 40 non-obese and obese adults between 20–60 years. Their height, weight and waist circumference were recorded. Student's t-test was done and Pearson's correlation was used to show a relationship between WC and the spirometric variables. Significant differences were observed in forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), expiratory reserve volume (ERV), inspiratory reserve volume (IRV) and maximum voluntary ventilation (MVV) between the obese and non-obese groups. WC showed a significant negative association with FEV1, FVC, ERV and MVV. The mechanisms underlying this association need to be further explored.

Dynamics of end expiratory lung volume after changing positive end-expiratory pressure in acute respiratory distress syndrome patients.

IntroductionLung recruitment maneuvers followed by an individually titrated positive end-expiratory pressure (PEEP) are the key components of the open lung ventilation strategy in acute respiratory distress syndrome (ARDS). The staircase recruitment maneuver is a step-by-step increase in PEEP followed by a decremental PEEP trial. The duration of each step is usually 2 minutes without physiologic rationale.MethodsIn this prospective study, we measured the dynamic end-expiratory lung volume changes (ΔEELV) during an increase and decrease in PEEP to determine the optimal duration for each step. PEEP was progressively increased from 5 to 40 cmH2O and then decreased from 40 to 5 cmH2O in steps of 5 cmH2O every 2.5 minutes. The dynamic of ΔEELV was measured by direct spirometry as the difference between inspiratory and expiratory tidal volumes over 2.5 minutes following each increase and decrease in PEEP. ΔEELV was separated between the expected increased volume, calculated as the product of the respiratory system compliance by the change in PEEP, and the additional volume.ResultsTwenty-six early onset moderate or severe ARDS patients were included. Data are expressed as median [25th-75th quartiles]. During the increase in PEEP, the expected increased volume was achieved within 2[2-2] breaths. During the decrease in PEEP, the expected decreased volume was achieved within 1 [1–1] breath, and 95 % of the additional decreased volume was achieved within 8 [2–15] breaths. Completion of volume changes in 99 % of both increase and decrease in PEEP events required 29 breaths.ConclusionsIn early ARDS, most of the ΔEELV occurs within the first minute, and change is completed within 2 minutes, following an increase or decrease in PEEP.

3D lung motion assessments on inspiratory/expiratory thin-section CT: Capability for pulmonary functional loss of smoking-related COPD in comparison with lung destruction and air trapping

PurposeTo evaluate the utility of three-dimensional (3D) lung motion on inspiratory and expiratory CT for pulmonary functional loss in smoking-related COPD in comparison with lung destruction and air trapping assessments. Method and materialsForty-four consecutive smokers and COPD patients prospectively underwent inspiratory and expiratory CT. A 3D motion vector map was generated from these CTs, and regional motion magnitudes were measured at the horizontal axis (X-axis), the ventrodorsal axis (Y-axis), and the craniocaudal axis (Z-axis). All mean magnitudes within the entire lung (MMLX, MMLY, and MMLZ) were normalized by expiratory CT lung volume. Moreover, CT-based functional lung volume (FLV) on inspiratory CT and air trapping lung volume (ATLV) on expiratory CT were assessed quantitatively. To evaluate the capability for pulmonary function loss assessment, all MMLs were correlated with pulmonary function tests. Then, discrimination analysis was performed to determine the concordance capability for clinical stage, and correct classification capabilities were compared by means of McNemar’s test. ResultsMultiple regression analysis showed MMLY (β=0.657, p<0.001) and FLV (β=0.375, p=0.019) were correlated with percentage of predicted forced expiratory volume in 1 second. Correct classification capabilities using patient characteristics and MMLs (68.2 (30/44)%) were significantly higher than those obtained by patient characteristics, FLV, and ATLV (54.5 (24/44)%), p=0.031). Conclusion3D lung motion parameter assessment is useful for smoking-related COPD assessment as well as lung parenchymal destruction and/or air trapping evaluations.

Pulmonary function tests and computed tomography lung attenuation in chronic obstructive pulmonary disease.

In the August 2015 issue of Radiology, Paoletti et al. reported the results of a study showing lack of linear correlation between pulmonary function tests (PFT) and lung attenuation on computed tomography (CT) in 132 patients with chronic obstructive pulmonary disease (COPD) (1). PFT were assessed according to the recommended and standardized procedures and measurements (2-4). Lung attenuation was measured with CT densitometry which unfortunately is not a standardized procedure both on the side of acquisition technique and on the side of image processing and measurements (5). In particular CT densitometry implies scanning the patient lying supine while she/he maintains breath-hold at end inspiration or expiration. Variables on the acquisition side include the inspiratory or expiratory lung volumes reached by the patient, number and collimation of sections, radiation dose and scanner calibration. Variables on the image processing and measurements side include application of reconstruction filters, automatic or semiautomatic segmentation of the lungs, correction for lung volume, automatic creation of histograms of density distribution and choice of measurement parameters to describe lung structural or functional status. Currently the main indications of lung CT densitometry in COPD include differentiation of emphysema and chronic bronchitis components in the single patient (alone or in combination with airways measurements) (6), monitoring progression of smoke-related pulmonary emphysema (7) and to be used as surrogate marker in trials assessing replacement therapy in alfa1-deficiency emphysema (8).

Rib Fracture Fixation Restores Inspiratory Volume and Peak Flow in a Full Thorax Human Cadaveric Breathing Model.

Background:Multiple rib fractures cause significant pain and potential for chest wall instability. Despite an emerging trend of surgical management of flail chest injuries, there are no studies examining the effect of rib fracture fixation on respiratory function.Objectives:Using a novel full thorax human cadaveric breathing model, we sought to explore the effect of flail chest injury and subsequent rib fracture fixation on respiratory outcomes.Patients and Methods:We used five fresh human cadavers to generate negative breathing models in the left thorax to mimic physiologic respiration. Inspiratory volumes and peak flows were measured using a flow meter for all three chest wall states: intact chest, left-sided flail chest (segmental fractures of ribs 3 - 7), and post-fracture open reduction and internal fixation (ORIF) of the chest wall with a pre-contoured rib specific plate fixation system.Results:A wide variation in the mean inspiratory volumes and peak flows were measured between specimens; however, the effect of a flail chest wall and the subsequent internal fixation of the unstable rib fractures was consistent across all samples. Compared to the intact chest wall, the inspiratory volume decreased by 40 ± 19% in the flail chest model (P = 0.04). Open reduction and internal fixation of the flail chest returned the inspiratory volume to 130 ± 71% of the intact chest volumes (P = 0.68). A similar 35 ± 19% decrease in peak flows was seen in the flail chest (P = 0.007) and this returned to 125 ± 71% of the intact chest following ORIF (P = 0.62).Conclusions:Negative pressure inspiration is significantly impaired by an unstable chest wall. Restoring mechanical stability of the fractured ribs improves respiratory outcomes similar to baseline values.