Inspiratory Volume Research Articles

Positive pressure ventilation coaching during neonatal bag-mask ventilation: A simulation-based pilot study.

Positive pressure ventilation (PPV) is the most important procedure during neonatal resuscitation. Providing effective PPV seems easy. However, performing the procedure correctly is extremely challenging. Airway obstruction and face mask large leaks are common. It is estimated that two-thirds of continued neonatal respiratory depression after the time of birth is caused by ineffective or improperly provided PPV. Finding methods to improve PPV performance are critically needed. Performance coaching is a simple and easy method of improving performing in procedural skills, and has been used previously to optimize compression technique. We performed the simulation-based pilot study to evaluate the impact of PPV coaching during neonatal bag-mask ventilation. Randomized cross-over study of nurses performing PPV on a SMART Newborn Resuscitation Training System with, and without, coaching. The PPV coach provided real-time feedback on chest rise, mask hold, and ventilation rate. The SMART system captured data on peak inspiratory pressure (PIP), tidal volume (Vt), mask leak, and ventilation rate. Data were analyzed by a blinded reviewer. PPV coaching resulted in more appropriate PIPs (34 cmH2O, IQR 32-38 vs. 36 cmH2O, IQR 28-37; P < 0.001), lower Vt (4.7 ml/kg, IQR 4-8 vs. 5.5 ml/kg, IQR 4-13; P < 0.001), and less mask leak (39% leak, IQR 21-70 vs. 45%, IQR 22-98; P = 0.005). There was no difference in respiratory rate (P = 0.93). Coaching improved PPV performance in this simulation-based pilot study. Further research on PPV coaching during neonatal resuscitation is warranted.

Use of tracheal ultrasound combined with clinical parameters to select left double-lumen tube size: A prospective observational study.

Left double-lumen tubes (LDLTs) are used in thoracic surgery to allow one-lung ventilation. Their size is usually chosen on the basis of clinical parameters (height, sex). Double-lumen endobronchial tubes are frequently undersized/oversized, risking tube displacement or tracheal trauma. A correlation between ultrasound tracheal diameter and left main bronchus dimension has been demonstrated. We hypothesised that the insertion of undersized/oversized double-lumen tubes is frequent when the size is selected using standard criteria, and that the use of ultrasound to estimate tracheal diameter may help to reduce the frequency of insertion of oversized tubes. Two-step prospective observational study. The operating room of a French University hospital from January 2016 to February 2017. We enrolled 102 and 50 consecutive patients undergoing elective thoracic surgery in Steps 1 and 2 (males 63.7 and 60.0%, age 63 (13) and 63 (11) years, height 170 (13) and 169 (9) cm, respectively). In Step 1, the size of the LDLT inserted was selected on the basis of clinical parameters. Ultrasound data about tracheal diameter were collected to determine cut-off points associating height and tracheal diameter. Cut-off values for ultrasound tracheal diameter were applied retrospectively to test their capability to reduce the insertion rate of oversized tube. In Step 2, the LDLT size was chosen according to the determined combined cut-off values. LDLT size was considered adequate if the bronchial cuff volume required for isolation of the lung (i.e. no difference between inspiratory and expiratory lung volumes) was 0.5 to 2.5 ml of air; undersized and oversized tubes required more than 2.5 ml and less than 0.5 ml, respectively. In Step 1, LDLT size was appropriate/undersized/oversized in 40 (39.2%)/23 (22.6%)/39 (38.6%) of patients. Cut-off values derived from ultrasound measurements would have reduced the use of oversized tubes by 20.6% (P < 0.001). In Step 2, the frequency of use of adequately sized tubes increased (86.0 vs. 39.2%, P < 0.001), and the frequency of insertion of oversized and undersized tubes decreased (6.0 vs. 38.2% and 8.0 vs. 22.6%, both P < 0.001). Combining ultrasound measurement of tracheal diameter and clinical parameters improves the choice of LDLT size.

Behavioral and Cognitive Reactions of Rats with Experimental Chronic Obstructive Lung Diseases of Different Degree

The study presents the results of behavioral phenotyping of rats with experimental chronic obstructive pulmonary disease (eCOPD) of different severity modeled by using a combination of inductors (purified papain and bacterial LPS) in increasing concentrations. Locomotor and exploratory activity, spatial memory, and anxiety were evaluated. In mild eCOPD, locomotor and exploratory activity increased, while other parameters did not differ from the control values. Rats with moderate eCOPD demonstrated moderately restricted locomotor function and increased anxiety. Severe eCOPD was associated with pronounced changes in all analyzed parameters. Correlation analysis revealed relationships between some behavioral parameters and blood oxygen saturation, inspiratory lung volume, and respiration rate. This indicates the role of respiratory failure in the pathogenesis of cognitive disorders.

Correlation between diaphragmatic sagittal rotation and pulmonary dysfunction in patients with ankylosing spondylitis accompanied by kyphosis.

ObjectiveThis study was performed to investigate the correlation between pulmonary dysfunction patterns and diaphragmatic sagittal rotation in patients with ankylosing spondylitis accompanied by kyphosis.MethodsThirty patients (27 male, 3 female) with kyphotic deformity secondary to ankylosing spondylitis underwent pedicle subtraction osteotomy and were retrospectively reviewed. All patients had undergone preoperative computed tomography with three-dimensional reconstruction, full-length spine radiographs, and pulmonary function tests. The diaphragmatic angle in the median sagittal plane (DA), pulmonary function test results, and radiological parameters were studied.ResultsCorrelation coefficients were used to present the correlation between the DA and pulmonary function and the global kyphosis (GK), respectively. The data analysis presented positive correlations between the DA value and vital capacity (VC), forced vital capacity (FVC), expiratory reserve volume (ERV), inspiratory reserve volume (IRV) and peak expiratory flow (PEF). There was likewise a negative correlation between DA value and the global kyphosis (GK). Additionally, there were further significantly statistical improvements for DA, ERV, IRV, FVC, and VC, PEF, postoperatively.ConclusionsExcept for the restriction of the chest wall motion and the abnormalities of lung parenchyma, the diaphragmatic sagittal rotation is also an influencing factor of pulmonary dysfunction in patients with ankylosing spondylitis accompanied by kyphosis.

Visual Obstruction of Flow Indicator Increases Inspiratory Volumes in Incentive Spirometry.

Incentive spirometers were developed to facilitate sustained maximum inspiration. In addition to a slow-rising float that indicates volume displacement, the incentive spirometers includes a sensitive, rapid-fluttering flow indicator. Achieving the target inspiratory volume is believed to be the most important factor in successful incentive spirometers use. This investigation hypothesized that patients focus on the rapid fluttering of the flow indicator rather than volume float during incentive spirometers use. The effects of adjusting hand positioning to cover the flow indicator on inspiratory volumes were evaluated. A randomized, prospective, counter-balanced crossover analysis of postoperative subjects was completed. In alternating assignment, the subjects were randomized to 1 of 2 study groups: (A) with the flow indicator covered first followed by the flow indicator standard exposed, and (B) with the flow indicator standard exposed first, followed by the flow indicator covered. The subjects were asked to perform 2 inhalations on their incentive spirometers in the first flow indicator condition: covered or the standard exposed. After a 2-min delay, the subjects were then asked to perform an additional 2 inhalations with the alternate flow indicator condition. The difference between mean inspiratory volumes under covered and standard exposed conditions was evaluated for all subjects, within and between groups. A total of 42 subjects were evaluated. For all the subjects, there was a mean increase of 255.4 mL of inspired volume when the flow indicator was covered (1,869.0 vs 1,613.7 mL, P < .001). For the subjects in group B who had their flow indicators covered after standard exposure, mean inspiratory volumes increased by 285.7 mL (1,613.1 vs 1,898.8 mL, P = .009). For subjects in group A who had their flow indicator covered before standard exposure, their mean inspiratory volumes increased by 225.0 mL (1,614.3 vs 1839.3 mL, P = .007) when covered. There was no significant difference between the mean increases across patients in groups A and B (225.0 vs 285.7 mL, P = .63). Covering the flow indicator during incentive spirometers significantly increased achieved inspiratory volumes. Increased volumes were generated, irrespective of flow indicator covering order, which strongly suggested that the covering effect was greater than any learning or condition order carry-over effects. Because achieving target inspiratory volumes is considered the most important factor in successful incentive spirometers use, these findings may have immediate applications for improving incentive spirometers protocols, patient education, and device design implications.

Inspiratory Muscle Warm-up Improves 3,200-m Running Performance in Distance Runners.

Barnes, KR and Ludge, AR. Inspiratory muscle warm-up improves 3,200-m running performance in distance runners. J Strength Cond Res 35(6): 1739-1747, 2021-This study examined the effects of an inspiratory muscle exercise as part of a warm-up (IMW) using a resisted breathing trainer on running performance. In a randomized crossover design, 17 trained distance runners completed two 3,200-m performance trials on separate days, preceded by 2 different warm-up procedures: IMW or sham IMW (CON). In each condition, subjects performed 30 breaths against either 50% of each athlete's peak strength (IMW) or 30 slow protracted breaths against negligible resistance (CON). Perceived race readiness and inspiratory muscle strength, flow, power, and volume were measured before and after each warm-up. Heart rate (HR), rating of perceived exertion (RPE) and dyspnea (RPD), and expired gases were collected during each trial. A 3,200-m run performance was 2.8% ± 1.5% (20.4-second) faster after IMW (effect size [ES] = 0.37, p = 0.02). After each warm-up condition, there was as small effect on peak inspiratory strength (6.6 ± 4.8%, ES = 0.22, p = 0.02), flow (5.2 ± 4.4%, ES = 0.20, p = 0.03), power (17.6 ± 16.7%, ES = 0.22, p = 0.04), and volume (6.7 ± 6.3%, ES = 0.24, p = 0.01) after IMW compared with CON. There were no differences in HR, minute volume, peak V̇o2, or V̇o2 at each 800-m interval between conditions (ES ≤ 0.13, p > 0.17). There were small differences in RPE at 800 m and 1,600 m (ES = 0.32, p = 0.17; ES = 0.21, p = 0.38, respectively), but no difference at the last 1,600 m (p = 1.0). There was a moderate positive effect on RPD (ES = 0.81, p < 0.001) and race readiness (ES = 0.76, p < 0.01) after IMW. Overall, the data suggest that IMW improves 3,200-m performance because of enhancements in inspiratory muscle function characteristics and reduction in dyspnea.

Sensory consequences of critical inspiratory constraints during exercise in pulmonary arterial hypertension

We aimed to assess detailed ventilatory and sensory responses to exercise contrasting subjects with and without PAH.20 non-smoking patients with PAH (37.5 ± 12.1 ys; FEV1/FVC = 0.77 ± 0.04; mPAP by heart catheterization = 50.6 ± 18.1 mmHg) and 10 matched controls performed cycling cardiopulmonary exercise test with serial assessments of dyspnea, airway occlusion pressure during the first 0.1 s (P0.1) of tidal volume and inspiratory capacity (IC).Patients showed lower spirometric variables compared to controls. Dyspnea and ventilation (VE) were significantly higher in patients for a given work rate. Dyspnea persisted more intense in patients even when expressed as a function of VE. Lower IC at rest (in non-hyperinflators; n = 10) or exercise-induced reduction in IC (in hyperinflators) predisposed patients to achieve earlier and at lower workloads a critical inspiratory reserve volume (IRV). At this point, there was a sudden rise in P0.1 and dyspnea perception.Attainment of a critical IRV at premature workloads leads to neuromechanical dissociation with an abrupt increment in exertional dyspnea.

Respiratory mechanics and cerebral blood flow during heat-induced hyperventilation and its voluntary suppression in passively heated humans.

We investigated whether heat‐induced hyperventilation can be voluntarily prevented, and, if so, how this modulates respiratory mechanics and cerebral blood flow in resting heated humans. In two separate trials, 10 healthy men were passively heated using lower body hot‐water immersion and a water‐perfused garment covering their upper body (both 41°C) until esophageal temperature (T es) reached 39°C or volitional termination. In each trial, participants breathed normally (normal‐breathing) or voluntarily controlled minute ventilation (V E) at a level equivalent to that observed after 5 min of heating (controlled‐breathing). Respiratory gases, middle cerebral artery blood velocity (MCAV), work of breathing, and end‐expiratory and inspiratory lung volumes were measured. During normal‐breathing, V E increased as T es rose above 38.0 ± 0.3°C, whereas controlled‐breathing diminished the increase in V E (V E at T es = 38.6°C: 25.6 ± 5.9 and 11.9 ± 1.3 L min−1 during normal‐ and controlled‐breathing, respectively, P < 0.001). During normal‐breathing, end‐tidal CO2 pressure and MCAV decreased with rising T es, but controlled‐breathing diminished these reductions (at T es = 38.6°C, 24.7 ± 5.0 vs. 39.5 ± 2.8 mmHg; 44.9 ± 5.9 vs. 60.2 ± 6.3 cm sec−1, both P < 0.001). The work of breathing correlated positively with changes in V E (P < 0.001) and was lower during controlled‐ than normal‐breathing (16.1 ± 12.6 and 59.4 ± 49.5 J min−1, respectively, at heating termination, P = 0.013). End‐expiratory and inspiratory lung volumes did not differ between trials (P = 0.25 and 0.71, respectively). These results suggest that during passive heating at rest, heat‐induced hyperventilation increases the work of breathing without affecting end‐expiratory lung volume, and that voluntary control of breathing can nearly abolish this hyperventilation, thereby diminishing hypocapnia, cerebral hypoperfusion, and increased work of breathing.

Effect of forward head posture on thoracic shape and respiratory function.

[Purpose] This study investigated the effect of forward head posture on upper and lower thoracic shape in adults to better understand the relationship between a forward head posture and respiratory function. [Participants and Methods] Fifteen healthy males were recruited after obtaining informed consent from all participants. All participants were instructed to respire in both the forward and neutral head postures while seated. Respiratory function was assessed using spirometry. Thoracic shape during respiration was assessed using 23 markers on both the upper and the lower thorax and compared between the 2 postures. [Results] Forced vital capacity, expiratory and inspiratory reserve volumes, forced expiratory volume at 1 second, and the peak flow rate observed with the forward head posture were significantly lower than that with the neutral head posture. The upper thorax showed a greater forward shift and the lower thorax showed a greater forward and inward shift with the forward head posture than with the neutral head posture. No significant difference in upper thoracic mobility was observed during respiration between the forward head posture and the neutral head posture. However, mobility of the lower thorax during respiration was significantly reduced with the forward head posture. [Conclusion] The forward head posture causes expansion of the upper thorax and contraction of the lower thorax, and these morphological changes cause decreased respiratory function.

Effect of neurally adjusted ventilatory assist on trigger of mechanical ventilation in acute exacerbation of chronic obstructive pulmonary disease patients with intrinsic positive end-expiratory pressure

Objective: To compare the trigger delay and work of trigger between neurally adjusted ventilatory assist (NAVA) and pressure support ventilation (PSV) in acute exacerbation of chronic obstructive pulmonary disease (AECOPD) patients with intrinsic positive end-expiratory pressure (PEEP) during mechanical ventilation. Methods: AECOPD patients with intrinsic PEEP (PEEPi) greater than or equal to 3 cmH(2)O (1 cmH(2)O=0.098 kPa) were enrolled during invasive mechanical ventilation. Subjects were ventilated with low, medium and high pressure under either NAVA or PSV mode. Servo Tracker software continuously recorded the waveform of ventilator and respiratory mechanics indexes (including respiratory frequency, inspiratory tidal volume (Vti), minute ventilation volume (VE), peak airway pressure (PIP), inspiratory time), and calculated trigger and expiratory conversion delay time, work of trigger and total work of breath. Results: A total of 14 AECOPD patients were enrolled with the average PEEPi (4.3±1.3) cmH(2)O. PSV inspiratory trigger delay time was positively correlated with PEEPi (r=0.913, P<0.05). Compared with PSV, NAVA significantly decreased trigger delay time in low, medium and high pressure level groups [(48±17) ms vs. (167±86) ms, (63±65) ms vs. (247±240) ms, (63±49) ms vs. (342±192) ms,respectively all P<0.05]. Similar results were shown as to work of trigger [(0.92±0.36) μV∙s vs. (1.22±0.70) μV∙s, (1.08±0.51) μV∙s vs. (1.62±1.25) μV∙s, (1.20±0.96) μV∙s vs. (2.29±1.02) μV∙s, all P<0.05]. Trigger delay time increased according to the increase of pressure level in PSV mode. Conclusion: The presence of PEEPi in AECOPD patients leads to obvious trigger delay under PSV mode, which is positively correlated with PEEPi level. NAVA significantly reduces trigger delay time and work of trigger compared with PSV mode.

The Change of Pulmonary Functions According to Age Increasing in Elderly Women

The aim of this study was to examine the affects of increased age on the pulmonary functions in elderly women. Methods : The subjects of this study were 68 healthy elderly women without lung and heart disease. Subjects were classified in the following age categories: 60s, 70s and 80s. The study’s methods and purpose were explained and these women agreed to participate. The items of pulmonary function were maximal-effort expiratory capacity(MEC), slow vital capacity(SVC), maximum inspiratory pressure(MIP) and maximum expiratory pressure(MEP). A spirometry (Pony FX, COSMED Inc, Italy) was used for measuring of the pulmonary functions in elderly women. The test was performed 3 times, and its mean value was used for analysis. Result : An ANOVA test was used to compare the change of pulmonary functions among categorized age in elderly women. Among the items in MEC, forced vital capacity(FVC) and forced expiratory volume in 1 second(FEV1) were significant difference according to increased age . In case of SVC, there was a significant difference in inspiratory capacity(IC), vital capacity(VC) and inspiratory reserve volume(IRV). Also, MIP and MEP were different significantly among categorized age. Especially, items which were FVC, FEV1, IC, VC, IRV and MIP were significant difference between 80s and 60s, between 80s and 70s. MIP was significant difference only between 80s and 60s. Conclusion : This study demonstrated that pulmonary functions decreased remarkably as age increasing. Especially, this study showed that the age of 80s in elderly women is the critical time which pulmonary functions were decreasing significantly.

Effect of Abdominal Binding on Diaphragmatic Neuromuscular Efficiency, Exertional Breathlessness, and Exercise Endurance in Chronic Obstructive Pulmonary Disease.

We tested the hypothesis that abdominal binding (AB) would reduce breathlessness and improve exercise tolerance by enhancing neuromuscular efficiency of the diaphragm during exercise in adults with chronic obstructive pulmonary disease (COPD). In a randomized, controlled, crossover trial, 20 adults with COPD (mean ± SD FEV1, 60 ± 16% predicted) completed a symptom-limited constant-load cycle endurance exercise test at 75% of their peak incremental power output with concomitant measures of the diaphragm electromyogram (EMGdi) and respiratory pressures without (CTRL) vs. with AB sufficient to increase end-expiratory gastric pressure (Pga,ee) by 6.7 ± 0.3 cmH2O at rest. Compared to CTRL, AB enhanced diaphragmatic neuromuscular efficiency during exercise (p < 0.05), as evidenced by a 25% increase in the quotient of EMGdi to tidal transdiaphragmatic pressure swing. By contrast, AB had no demonstrable effect on exertional breathlessness and exercise tolerance; spirometry and plethysmography-derived pulmonary function test parameters at rest; and cardiac, metabolic, breathing pattern, inspiratory reserve volume and EMGdi responses during exercise (all p > 0.05 vs. CTRL). In conclusion, enhanced neuromuscular efficiency of the diaphragm during exercise with AB was not associated with relief of exertional breathlessness and improved exercise tolerance in adults with COPD.Clinical Trial Registration: ClinicalTrials.gov Identifier: NCT01852006.

Effects of aerosol inhalation on respiratory mechanical parameters under different ventilation patterns and ventilator parameters

To investigate the effects of aerosol inhalation on respiratory mechanical parameters under different ventilation patterns and ventilator parameters in patients on mechanical ventilation and simulated model of aqualung in vitro. (1) Clinical research: the patients needed sedative undergoing mechanical ventilation admitted to intensive care unit (ICU) of Qingdao Municipal Hospital from January 2016 to January 2018 were enrolled. They were randomly divided into volume controlled ventilation (VCV) group and pressure controlled ventilation (PCV) group according to random number table. Main parameters setting of respirator: the predetermined tidal volume (VT) was set at 500 mL in the VCV group; the preset pressure was regulated, so that when the atomizer was connected to the atomization device, the VT was nearly equal to or slightly larger than 500 mL in the PCV group. Respiratory mechanical indices [peak airway pressure (Ppeak), inspiratory tidal volume (VTi), exhaled tidal volume (VTe)] were recorded before atomization (atomized oxygen flow was 0) and 10 minutes after the beginning of atomization under the condition of 7 L/min and 9 L/min of atomized oxygen flow respectively. (2) Simulated scuba test in vitro: the ventilator was connected to the simulated scuba, and an external mechanical ventilation model was constructed. They were divided into VCV group and PCV group according to ventilation mode. Main parameters setting of respirator: VCV group was given 450, 550, 650 mL preset VT, and PCV group was given 12, 16, 20 cmH2O (1 cmH2O = 0.098 kPa) preset suction pressure. The changes in respiratory mechanical indexes were observed under different ventilation patterns and ventilator parameters of 0 (only connected with atomizing device), 5, 7, 9 L/min atomizing oxygen flow. (1) Clinical research results: all 77 patients were enrolled in the final analysis, including 20 patients with 7 L/min of atomized oxygen flow under VCV mode, 18 patients with 9 L/min of atomized oxygen flow, and 21 patients with 7 L/min of atomized oxygen flow under PCV mode and 18 patients with 9 L/min of atomized oxygen flow. Under VCV mode, the levels of Ppeak and VTe were increased with the increase in atomized oxygen flow, and there was significant difference at 9 L/min as compared with those before atomization [Ppeak (cmH2O): 29.44±4.58 vs. 24.39±4.64, VTe (mL): 896.26±24.91 vs. 497.61±8.67, both P < 0.05]. There was no significant change in VTi, and no significant difference at 9 L/min of atomized oxygen flow as compared with that before atomization (mL: 494.67±3.07 vs. 492.61±6.05, P > 0.05). Under PCV mode, with the increase in oxygen atomization flow, VTi was decreased gradually, and VTe was increased gradually, with significant difference as compared with those before atomization when the atomized oxygen flow was 9 L/min [VTi (mL): 322.78±17.75 vs. 518.17±8.97, VTe (mL): 730.89±31.20 vs. 519.00±9.06, both P < 0.05]. There was no significant change in Ppeak, and no significant difference at 9 L/min of atomized oxygen flow as compared with that before atomization (cmH2O: 21.44±2.23 vs. 21.39±2.55, P > 0.05). (2) Simulated scuba results in vitro: under VCV mode, VTe monitored by respirator and VT showed by simulated scuba in different preset VT groups were continuously increased with the increase in oxygen atomization flow, while VTi monitored by ventilator was not significantly changed. At 10 minutes after the beginning of atomization, the VTi monitored by ventilator in different preset VT groups was significantly lower than VT showed by simulated water lung (mL: 649.67±5.03 vs. 840.00±10.00 at 650 mL of preset VT and 9 L/min of atomized oxygen flow, P < 0.05), and VTe was significantly higher than VT showed by simulated water lung (mL: 1 270.33±11.06 vs. 840.00±10.00 at 650 mL of preset VT and 9 L/min of atomized oxygen flow, P < 0.05). Under PCV mode, with the increase in atomized oxygen flow, VTi monitored by ventilator in different preset suction pressure groups was decreased gradually, and VTe was increased gradually, but Ppeak monitored by ventilator did not changed significantly. At 10 minutes after the beginning of atomization, the VTi monitored by ventilator in different preset suction pressure groups was significantly lower than VT showed by simulated water lung (mL: 917.33±4.51 vs. 1 103.33±5.77 at 20 cmH2O of preset suction pressure and 9 L/min of atomized oxygen flow, P < 0.05), and VTe was significantly higher than VT showed by simulated water lung (mL: 1 433.33±4.73 vs. 1 103.33±5.77 at 20 cmH2O of preset suction pressure and 9 L/min of atomized oxygen flow, P < 0.05). Under the VCV mode, the oxygen flow outside the atomization could lead to the increase in VT of the patient side, while under the PCV mode, the VT and Ppeak in the patient side had no significant change. Both VTi and VTe monitored by ventilator could not reflect the patient's VT under either VCV or PCV mode.

Correlation Between Anthropometric, Physical Fitness Traits, Lung Capacity, and Success of Iranian Elite Greco-Roman Wrestlers

Objectives: This study aimed to evaluate how lung capacity and anthropometric and physical fitness traits are associated with success of Iranian elite Greco-Roman wrestlers. Methods: Twenty-five male Iranian elite Greco-Roman wrestlers (22 ± 4 years old) (both of light and heavy weights) participated in the present study. Anthropometric characteristics, physical fitness traits, and lung capacity were tested in the exercise physiology laboratory. Results: Our results showed a significant and positive correlation between arm span, as the only anthropometric trait, and success of Iranian elite Greco-Roman wrestlers. Also, maximal oxygen consumption, dead lift, squat, bench press, agility, shoulder and wrist elevation, sit and reach, eye/left hand reaction time, eye/foot reaction time, ear/left hand reaction time, ear/foot reaction time were positively correlated with success. Furthermore, there were significant and positive correlations between inspiratory reserve volume, tidal volume, forced vital capacity, forced expiratory volume (in one second), maximal voluntary ventilation, and success. In contrast, we observed a negative and significant correlation between body fat (%) and success of Iranian elite Greco-Roman wrestlers. Conclusions: Physical fitness traits and lung capacity have a greater potential than anthropometric characteristics in the prediction of Greco-Roman wrestler’s success in championship levels.

Assessment of changes of regional ventilation distribution in the lung tissue depending on the driving pressure applied during high frequency jet ventilation

BackgroundElectrical impedance tomography (EIT) is a tool to monitor regional ventilation distribution in patient’s lungs under general anesthesia. The objective of this study was to assess the regional ventilation distribution using different driving pressures (DP) during high frequency jet ventilation (HFJV).MethodsProspective, observational, cross-over study. Patients undergoing rigid bronchoscopy were ventilated HFJV with DP 1.5 and 2.5 atm. Hemodynamic and ventilation parameters, as well as ventilation in different regions of the lungs in percentage of total ventilation, assessed by EIT, were recorded.ResultsThirty-six patients scheduled for elective rigid bronchoscopy. The final analysis included thirty patients. There was no significant difference in systolic, diastolic and mean arterial blood pressure, heart rate, and peripheral saturation between the two groups. Peak inspiratory pressure, mean inspiratory pressure, tidal volume, and minute volume significantly increased in the second, compared to the first intervention group. Furthermore, there were no statistically significant differences between each time profiles in all ROI regions in EIT.ConclusionsIn our study intraoperative EIT was an effective method of functional monitoring of the lungs during HFJV for rigid bronchoscopy procedure. Lower driving pressure was as effective in providing sufficient ventilation distribution through the lungs as the higher driving pressure but characterized by lower airway pressure.Trial registrationThe study was registered on ClinicalTrials.gov under no. NCT02997072.

Lobe-wise assessment of lung volume and density distribution in lung transplant patients and value for early detection of bronchiolitis obliterans syndrome

PurposeTo evaluate quantitative computed tomography (CT) measurements of the lung parenchyma in lung transplant (LTx) patients for early detection of the bronchiolitis obliterans syndrome (BOS). Materials and Methods359 CT scans of 122 lung transplant patients were evaluated. Measurements of lung volume and density were performed for the whole lung and separately for each lobe. For longitudinal analysis the difference between the baseline at 6 months after LTx and follow-up examinations was calculated. Patients with and without BOS (matched 1:2) were compared at two different time points, the last examination before the BOS onset and the first examination within one year after BOS onset. Results30 patients developed BOS during the follow-up period. Longitudinal changes in the lung volume and lung density measured on CT differed significantly between those patients with and without early BOS, in particular the difference of the inspiratory and expiratory lung volume (p < 0.001), the ratio of the expiratory and inspiratory lung volume (p < 0.001-p = 0.001) and MLD (p < 0.001-p = 0.001), the volume on expiration (p < 0.001-p = 0.007), the MLD on expiration (p < 0.001-p = 0.007), and the percentiles on expiration (p < 0.001-p = 0.002) with an increase of lung volume and a decrease of lung density. Changes were pronounced in the lower lobes. Before BOS onset, patients with and without future development of BOS showed no significant differences. ConclusionLongitudinal changes of lung volume and lung density measured on CT start markedly at BOS onset with increased lung volume and decreased lung density indicating increased inflation levels. Even though this method may help to diagnose BOS at onset it is not useful as a predictor for BOS before disease onset.

Positive end-expiratory pressure with I-gel in children, is it effective and safe?

BackgroundI-gel is designed to suit the anatomy of hypopharyngeal and perilaryngeal areas in adults without an inflatable cuff. There is insufficient evidence regarding quality of seal of I-gel during PEEP application in pediatric patients. The objective of this study was to evaluate the performance of I-gel usage in children during general anesthesia with PEEP application at a level of 5 cm H2O and assess whether it improves oxygenation.Patients and methodsA total of 42 ASA physical status I, and II children undergoing surgery under general anesthesia were included. Patients were randomly allocated to one of two equal groups to be on Pressure-control ventilation (PCV) with PEEP 5 cm H2O (group I) and PCV without PEEP (group II). I-gel size 2 1/2 was used in children weighing from 25 to 35 kg. Leak volume (LV) and leak fraction (LF) were recorded. Peak Inspiratory Pressure (PIP), expiratory and inspiratory tidal volume as well as minute volume and End tidal CO2 (ETCO2) were also recorded at 5 min, 30 min, and 1 h after I-gel insertion.ResultsLeak volume and leak fraction had no statistical significant differences between both groups. Patients with PEEP had significantly lower (ETCO2), higher PIP, higher inspiratory tidal volume, and higher expiratory tidal volume (p = 0.001) during the post I-gel insertion follow up period. Patients with PEEP also had significantly higher PaO2 and lower PaCO2 levels (p = 0.001).ConclusionsI-gel may be used safely during PCV while applying PEEP of 5 cm H2O in children with an effective seal pressure, improvement in oxygenation and without leak or gastric insufflation.

Effects of respiratory rehabilitation exercise for high level of cervical spinal cord injury: Novel approach

People with high level of spinal cord injury feel a lot of discomfort in breathing ability. However, the rehabilitation exercise program to solve this problem is not activated. Also, the respiratory rehabilitation exercise program developed specifically for those is very scarce. Existing breathing exercises are uncomfortable because the method is tedious and cannot see the degree of improvement. Therefore, it is important to develop a variety of exercise programs that can effectively enhance the respiratory muscle. The purpose of this study was to investigate the effect of respiratory rehabilitation exercise to improve pulmonary function. The subject were 7 people with high level of spinal cord injury (C3-6, ASIA A, B). The exercise program developed was consist of 8 weeks of 1-h exercise session 2 days a week. Each session included warm up (stretching), respiratory rehabilitation exercise, and cool down (flexibility and relaxation). The pulmonary functions were measured with digital spirometry meter (Pony FX, Cosmed, Italy). The pulmonary function tests were conducted before and after the 16 sessions of respiratory rehabilitation exercise program. As a result of respiratory rehabilitation exercise during 8-week for subjects, pulmonary function showed significant changes in inspiratory capacity, vital capacity and inspiratory reserve volume. We confirmed the positive effect of the respiratory rehabilitation exercise program developed for people with high level of spinal cord injury. The results of this study are expected to be used as basic data for the development of specialized programs for each degree of severity.

A Device for the Quantification of Oxygen Consumption and Caloric Expenditure in the Neonatal Range.

The accurate measurement of oxygen consumption (VO2) and energy expenditure (EE) may be helpful to optimize the treatment of critically ill patients. However, current techniques are limited in their ability to accurately quantify these end points in infants due to a low VO2, low tidal volume, and rapid respiratory rate. This study describes and validates a new device intended to perform in this size range. We created a customized device that quantifies inspiratory volume using a pneumotachometer and concentrations of oxygen and carbon dioxide gas in the inspiratory and expiratory limbs. We created a customized algorithm to achieve precise time alignment of these measures, incorporating bias flow and compliance factors. The device was validated in 3 ways. First, we infused a certified gas mixture (50% oxygen/50% carbon dioxide) into an artificial lung circuit, comparing measured with simulated VO2 and carbon dioxide production (VCO2) within a matrix of varying tidal volume (4-20 mL), respiratory rate (20-80 bpm), and fraction of inspired oxygen (0.21-0.8). Second, VO2, VCO2, and EE were measured in Sprague Dawley rats under mechanical ventilation and were compared to simultaneous Douglas bag collections. Third, the device was studied on n = 14 intubated, spontaneously breathing neonates and infants, comparing measured values to Douglas measurements. In all cases, we assessed for difference between the device and reference standard by linear regression and Bland-Altman analysis. In vitro, the mean ± standard deviation difference between the measured and reference standard VO2 was +0.04 ± 1.10 (95% limits of agreement, -2.11 to +2.20) mL/min and VCO2 was +0.26 ± 0.31 (-0.36 to +0.89) mL/min; differences were similar at each respiratory rate and tidal volume measured, but higher at fraction of inspired oxygen of 0.8 than at 0.7 or lower. In rodents, the mean difference was -0.20 ± 0.55 (-1.28 to +0.89) mL/min for VO2, +0.16 ± 0.25 (-0.32 to +0.65) mL/min for VCO2, and -0.84 ± 3.29 (-7.30 to +5.61) kcal/d for EE. In infants, the mean VO2 was 9.0 ± 2.5 mL/kg/min by Douglas method and was accurately measured by the device (bias, +0.22 ± 0.87 [-1.49 to +1.93] mL/kg/min). The average VCO2 was 8.1 ± 2.3 mL/kg/min, and the device exhibited a bias of +0.33 ± 0.82 (-1.27 to +1.94) mL/kg/min. Mean bias was +2.56% ± 11.60% of the reading for VO2 and +4.25% ± 11.20% of the reading for VCO2; among 56 replicates, 6 measurements fell outside of the 20% error range, and no patient had >1 of 4 replicates with a >20% error in either VO2 or VCO2. This device can measure VO2, VCO2, and EE with sufficient accuracy for clinical decision-making within the neonatal and pediatric size range, including in the setting of tachypnea or hyperoxia.

Exertional dyspnea and operating lung volumes in asthma.

Dyspnea has been reported to be a main contributor to exercise avoidance in asthma. While traditional markers of ventilation do not explain the heightened dyspnea during exercise in patients with asthma, this study proposed that exertional dyspnea in asthma was due to high-operating lung volumes, which may be improved with a short-acting β2-agonist. On two separate days, 16 patients with asthma and 16 controls completed a lung function test and incremental exercise tests to exhaustion. On one of the days (order randomized), 400 µg salbutamol was administered before exercise. Inspiratory capacity (IC), inspiratory reserve volume (IRV), and dyspnea (modified Borg scale) were evaluated throughout exercise. Compared with controls, patients with asthma reported greater dyspnea at the same absolute submaximal workloads. Furthermore, patients with asthma demonstrated altered breathing responses to exercise, characterized by reduced IC and IRV throughout exercise compared with controls. The reduced IRV was associated with increased dyspnea in patients with asthma. Salbutamol did not affect dyspnea or operating lung volumes in either group. The increased perception of dyspnea during incremental exercise in patients with asthma appears to be secondary to a reduction in IRV, which is unaffected by an inhaled β2-agonist. NEW & NOTEWORTHY Increased exertional dyspnea in asthma appears to be due to high operating lung volumes and is not affected by salbutamol.