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Concept: Vital capacity


BACKGROUND: Enhancing athletic performance is a great desire among the athletes, coaches and researchers. Mint is one of the most famous natural herbs used for its analgesic, anti-inflammatory, antispasmodic, antioxidant, and vasoconstrictor effects. Even though inhaling mint aroma in athletes has been investigated, there were no significant effects on the exercise performance. METHODS: Twelve healthy male students every day consumed one 500 ml bottle of mineral water, containing 0.05 ml peppermint essential oil for ten days. Blood pressure, heart rate, and spirometry parameters including forced vital capacity (FVC), peak expiratory flow rate (PEF), and peak inspiratory flow (PIF) were determined one day before, and after the supplementation period. Participants underwent a treadmill-based exercise test with metabolic gas analysis and ventilation measurement using the Bruce protocol. RESULTS: The FVC (4.57 +/- 0.90 vs. 4.79 +/- 0.84; p < 0.001), PEF (8.50 +/- 0.94 vs. 8.87 +/- 0.92; p < 0.01), and PIF (5.71 +/- 1.16 vs. 6.58 +/-1.08; p < 0.005) significantly changed after ten days of supplementation. Exercise performance evaluated by time to exhaustion (664.5 +/- 114.2 vs. 830.2 +/- 129.8 s), work (78.34 +/-32.84 vs. 118.7 +/- 47.38 KJ), and power (114.3 +/- 24.24 vs. 139.4 +/- 27.80 KW) significantly increased (p < 0.001). In addition, the results of respiratory gas analysis exhibited significant differences in VO2 (2.74 +/- 0.40 vs. 3.03 +/- 0.351 L/min; p < 0.001), and VCO2 (3.08 +/- 0.47 vs. 3.73 +/- 0.518 L/min; p < 0.001). CONCLUSIONS: The results of the experiment support the effectiveness of peppermint essential oil on the exercise performance, gas analysis, spirometry parameters, blood pressure, and respiratory rate in the young male students. Relaxation of bronchial smooth muscles, increase in the ventilation and brain oxygen concentration, and decrease in the blood lactate level are the most plausible explanations.

Concepts: Asthma, Atherosclerosis, Respiratory physiology, Medical signs, Spirometry, Exercise physiology, Vital capacity, Peak flow meter


A 6-second spirometry test is easier than full exhalations. We compared the reliability of the ratio of the Forced expiratory volume in 1 second/Forced expiratory volume in 6 seconds (FEV1/FEV6) to the ratio of the FEV1/Forced vital capacity (FEV1/FVC) for the detection of airway obstruction.

Concepts: Longitudinal study, Respiratory physiology, Ratio, Spirometry, Obstructive lung disease, Vital capacity, Airway obstruction


Background Air-pollution levels have been trending downward progressively over the past several decades in southern California, as a result of the implementation of air quality-control policies. We assessed whether long-term reductions in pollution were associated with improvements in respiratory health among children. Methods As part of the Children’s Health Study, we measured lung function annually in 2120 children from three separate cohorts corresponding to three separate calendar periods: 1994-1998, 1997-2001, and 2007-2011. Mean ages of the children within each cohort were 11 years at the beginning of the period and 15 years at the end. Linear-regression models were used to examine the relationship between declining pollution levels over time and lung-function development from 11 to 15 years of age, measured as the increases in forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) during that period (referred to as 4-year growth in FEV1 and FVC). Results Over the 13 years spanned by the three cohorts, improvements in 4-year growth of both FEV1 and FVC were associated with declining levels of nitrogen dioxide (P<0.001 for FEV1 and FVC) and of particulate matter with an aerodynamic diameter of less than 2.5 μm (P= 0.008 for FEV1 and P<0.001 for FVC) and less than 10 μm (P<0.001 for FEV1 and FVC). These associations persisted after adjustment for several potential confounders. Significant improvements in lung-function development were observed in both boys and girls and in children with asthma and children without asthma. The proportions of children with clinically low FEV1 (defined as <80% of the predicted value) at 15 years of age declined significantly, from 7.9% to 6.3% to 3.6% across the three periods, as the air quality improved (P=0.001). Conclusions We found that long-term improvements in air quality were associated with statistically and clinically significant positive effects on lung-function growth in children. (Funded by the Health Effects Institute and others.).

Concepts: Asthma, Respiratory physiology, Chronic obstructive pulmonary disease, Pollution, Spirometry, Smog, Air pollution, Vital capacity


OBJECTIVE: The aim of this study was to assess pulmonary function and its predictors in very low birth weight (birth weight ≤1,500 g) children (VLBWc) with or without bronchopulmonary dysplasia (BPD), born at gestational age ≤32 weeks at a single tertiary center during 1996-1999, after the introduction of surfactant therapy. METHODS: Of the 120 surviving VLBW children, 48 (40%) VLBWc (22 with prior-BPD) at age 8.5 ± 1.0 years and 46 age-matched controls (8.8 ± 1.4 years) born at term, underwent lung function study. RESULTS: Adjusted values (z-score) of forced vital capacity (z-FVC), forced expiratory volume in 1 sec (z-FEV1), forced expiratory flow 25-75% (z-FEF25-75), carbon monoxide lung diffusion capacity (z-DLCO), and DLCO/alveolar volume (z-DLCO/VA) were significantly lower than controls (mean difference, 95% CI: -1.35, -1.81 to -0.90, P < 0.001; -1.31, -1.73 to -0.90, P < 0.001; -0.87, -1.29 to -0.46, P < 0.001; -0.98, -1.72 to -0.23, P < 0.001; -0.70, -1.22 to -0.18, P < 0.05; respectively). Residual volume (z-RV) and RV/total lung capacity (RV/TLC) ratio (%) were significantly higher in VLBWc than controls (mean difference, 95% CI: 1.06, 0.44 to 1.68, P < 0.001; 9.54%, 5.73 to 13.3%, P < 0.001; respectively). No differences were found in lung function between VLBWc (no-BPD vs. BPD) with the exception of a significant higher RV/TLC ratio in the BPD-subgroup (mean difference, 95% CI: 7.0%, 0.4 to 13%, P = 0.03). Lung function abnormalities were found in 30 (63%) VLBWc with evidence of airway obstruction and diffusing capacity impairment. A weak relationship was observed between gestational age with z-FVC (r = 0.30, P = 0.04), birth weight with z-FEV1 (r = 0.30, P = 0.04) and RV/TLC ratio (r = -0.49, P = 0.001). The duration of oxygen treatment correlated negatively with the z-DLCO/Va (r = -0.5, P = 0.02). No differences were found in FeNO levels between VLBWc and controls. CONCLUSION: VLBWc at school age showed lung function abnormalities characterized by airway obstruction, hyperinflation, and diffusion impairment. Neonatal lung damage together with preterm birth may play a role in worsening the functional respiratory outcome. Pediatr Pulmonol. © 2012 Wiley Periodicals, Inc.

Concepts: Pulmonology, Lung, Fetus, Respiratory physiology, Obstetrics, Spirometry, Lung volumes, Vital capacity


PurposePompe disease results from lysosomal acid α-glucosidase (GAA) deficiency and its associated glycogen accumulation and muscle damage. Alglucosidase alfa (recombinant human GAA (rhGAA)) received approval in 2006 as a treatment for Pompe disease at the 160 L production scale. In 2010, larger-scale rhGAA was approved for patients up to 8 years old without cardiomyopathy. NCT01526785 evaluated 4,000 L rhGAA efficacy/safety in US infantile- or late-onset Pompe disease (IOPD, LOPD) patients up to 1 year old transitioned from 160 L rhGAA.MethodsA total of 113 patients (87 with IOPD; 26 with LOPD) received 4,000 L rhGAA for 52 weeks dosed the same as previous 160 L rhGAA. Efficacy was calculated as the percentage of patients stable/improved at week 52 (without death, new requirement for invasive ventilation, left ventricular mass z-score increase >1 if baseline was >2, upright forced vital capacity decrease ≥15% predicted, or Gross Motor Function Measure-88 decrease ≥8 percentage points). Safety evaluation included an extension ≤20 months.ResultsWeek 52 data was available for 104 patients, 100 of whom entered the extension. At week 52, 87/104 (83.7%) were stable/improved. Overall survival was 98.1% overall, 97.6% IOPD, 100% LOPD; 92.4% remained invasive ventilator-free (93.4% IOPD, 88.7% LOPD). Thirty-five patients had infusion-associated reactions. Eight IOPD patients died of drug-unrelated causes.ConclusionsMost Pompe disease patients were clinically stable/improved after transitioning to 4,000 L rhGAA. Safety profiles of both rhGAA forms were consistent.Genetics in Medicine advance online publication, 22 March 2018; doi:10.1038/gim.2018.2.

Concepts: Death, Respiratory physiology, Left ventricular hypertrophy, Standard deviation, Glycogen storage disease, Percentage point, Glycogen storage disease type II, Vital capacity


Background Currently, the diagnosis of chronic obstructive pulmonary disease (COPD) requires a ratio of forced expiratory volume in 1 second (FEV1) to forced vital capacity (FVC) of less than 0.70 as assessed by spirometry after bronchodilator use. However, many smokers who do not meet this definition have respiratory symptoms. Methods We conducted an observational study involving 2736 current or former smokers and controls who had never smoked and measured their respiratory symptoms using the COPD Assessment Test (CAT; scores range from 0 to 40, with higher scores indicating greater severity of symptoms). We examined whether current or former smokers who had preserved pulmonary function as assessed by spirometry (FEV1:FVC ≥0.70 and an FVC above the lower limit of the normal range after bronchodilator use) and had symptoms (CAT score, ≥10) had a higher risk of respiratory exacerbations than current or former smokers with preserved pulmonary function who were asymptomatic (CAT score, <10) and whether those with symptoms had different findings from the asymptomatic group with respect to the 6-minute walk distance, lung function, or high-resolution computed tomographic (HRCT) scan of the chest. Results Respiratory symptoms were present in 50% of current or former smokers with preserved pulmonary function. The mean (±SD) rate of respiratory exacerbations among symptomatic current or former smokers was significantly higher than the rates among asymptomatic current or former smokers and among controls who never smoked (0.27±0.67 vs. 0.08±0.31 and 0.03±0.21 events, respectively, per year; P<0.001 for both comparisons). Symptomatic current or former smokers, regardless of history of asthma, also had greater limitation of activity, slightly lower FEV1, FVC, and inspiratory capacity, and greater airway-wall thickening without emphysema according to HRCT than did asymptomatic current or former smokers. Among symptomatic current or former smokers, 42% used bronchodilators and 23% used inhaled glucocorticoids. Conclusions Although they do not meet the current criteria for COPD, symptomatic current or former smokers with preserved pulmonary function have exacerbations, activity limitation, and evidence of airway disease. They currently use a range of respiratory medications without any evidence base. (Funded by the National Heart, Lung, and Blood Institute and the Foundation for the National Institutes of Health; SPIROMICS number, NCT01969344 .).

Concepts: Pulmonology, Asthma, Lung, Respiratory physiology, Chronic obstructive pulmonary disease, Emphysema, Spirometry, Vital capacity


Background Bronchoscopic lung-volume reduction with the use of one-way endobronchial valves is a potential treatment for patients with severe emphysema. To date, the benefits have been modest but have been hypothesized to be much larger in patients without interlobar collateral ventilation than in those with collateral ventilation. Methods We randomly assigned patients with severe emphysema and a confirmed absence of collateral ventilation to bronchoscopic endobronchial-valve treatment (EBV group) or to continued standard medical care (control group). Primary outcomes were changes from baseline to 6 months in forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and 6-minute walk distance. Results Eighty-four patients were recruited, of whom 16 were excluded because they had collateral ventilation (13 patients) or because lobar segments were inaccessible to the endobronchial valves (3 patients). The remaining 68 patients (mean [±SD] age, 59±9 years; 46 were women) were randomly assigned to the EBV group (34 patients) or the control group (34). At baseline, the FEV1 and FVC were 29±7% and 77±18% of the predicted values, respectively, and the 6-minute walk distance was 374±86 m. Intention-to-treat analyses showed significantly greater improvements in the EBV group than in the control group from baseline to 6 months: the increase in FEV1 was greater in the EBV group than in the control group by 140 ml (95% confidence interval [CI], 55 to 225), the increase in FVC was greater by 347 ml (95% CI, 107 to 588), and the increase in the 6-minute walk distance was greater by 74 m (95% CI, 47 to 100) (P<0.01 for all comparisons). By 6 months, 23 serious adverse events had been reported in the EBV group, as compared with 5 in the control group (P<0.001). One patient in the EBV group died. Serious treatment-related adverse events in this group included pneumothorax (18% of patients) and events requiring valve replacement (12%) or removal (15%). Conclusions Endobronchial-valve treatment significantly improved pulmonary function and exercise capacity in patients with severe emphysema characterized by an absence of interlobar collateral ventilation. (Funded by the Netherlands Organization for Health Research and Development and the University Medical Center Groningen; Netherlands Trial Register number, NTR2876 .).

Concepts: Scientific method, Lung, Respiratory physiology, Emphysema, Prediction interval, Netherlands, Spirometry, Vital capacity


The purpose of this study was to elucidate the physiological mechanisms of sex differences in exertional dyspnea. We compared detailed measures of neural respiratory motor drive (diaphragm EMG expressed as a % of maximal EMGdi [EMGdi%max]), breathing pattern, operating lung volumes, dynamic respiratory mechanics (tidal esophageal [Pes,tidal%peak], and transdiaphragmatic [Pdi,tidal%peak] pressure swings expressed as a % of their respective peak values), and sensory intensity and unpleasantness ratings of dyspnea during symptom-limited incremental cycle exercise in healthy young women (n=25) and men (n=25). The tidal volume to forced vital capacity ratio (VT%FVC), breathing frequency, EMGdi%max, Pes,tidal%peak, Pdi,tidal%peak, and sensory intensity and unpleasantness ratings of dyspnea were higher, while dynamic inspiratory capacity and inspiratory reserve volume (IRV) were lower at a standardized absolute ventilation (VE) of 55 l min(-1) during submaximal exercise in women vs. men (all p<0.05). By contrast, sex had no demonstrable effect on the inter-relationships between exercise-induced increases in VT%FVC, EMGdi%max, and sensory intensity and unpleasantness ratings of dyspnea. The results of this study suggest that sex differences in the intensity and unpleasantness of exertional dyspnea in health likely reflect the awareness of a relatively higher neural respiratory motor drive (or EMGdi%max) needed to achieve any given VE during exercise in the setting of relatively greater dynamic mechanical constraints on VT expansion in women.

Concepts: Lung, Volume, Respiratory physiology, Gender, Respiratory system, Spirometry, Lung volumes, Vital capacity


Lung cancer is the leading cause of cancer-related death worldwide. For early stages of the disease, lung resection surgery remains the best treatment with curative intent, but significant morbidity is associated, especially among patients with poor pulmonary function and cardiorespiratory fitness. In those cases, the implementation of a preoperative exercise-based intervention could optimize patient’s functional status before surgery and improve postoperative outcomes and enhance recovery. The aim of this systematic review is to provide the current body of knowledge regarding the effectiveness of a preoperative exercise-based intervention on postoperative and functional outcomes in patients with lung cancer submitted to lung resection surgery. A systematic review of the literature using CINAHL, EMBASE, MEDLINE, Pubmed, PEDro and SCOPUS was undertaken in September 2015 yielding a total of 1656 references. Two independent reviewers performed the assessment of the potentially eligible records against the inclusion criteria and finally, 21 articles were included in the review. Articles were included if they examined the effects of an exercise-based intervention on at least one of the selected outcomes: pulmonary function, (functional) exercise capacity, health-related quality of life (HRQoL) and postoperative outcomes (length of stay and postoperative complications). Fourteen studies were further selected for a meta-analysis to quantify the mean effect of the intervention and generate 95% confidence intervals (CIs) using the Cochrane Review Manager 5.0.25. For two of the outcomes included (exercise capacity and HRQoL), studies showed large heterogeneity and thus, a meta-analysis was considered inappropriate. Pulmonary function (forced vital capacity and forced expiratory volume in 1 s) was significantly enhanced after the intervention [standardized mean difference (SMD) = 0.38; 95% CI 0.14, 0.63 and SMD = 0.27, 95% CI 0.11, 0.42, respectively]. In comparison with the patients in the control groups, patients in the experimental groups spent less days in the hospital (mean difference = -4.83, 95% CI -5.9, -3.76) and had a significantly reduced risk for developing postoperative complications (risk ratios = 0.45; 95% CI 0.28, 0.74). In conclusion, preoperative exercise-based training improves pulmonary function before surgery and reduces in-hospital length of stay and postoperative complications after lung resection surgery for lung cancer.

Concepts: Epidemiology, Cancer, Pulmonology, Cancer staging, Evidence-based medicine, Respiratory physiology, Spirometry, Vital capacity


Over the past two and a half decades, many clinical trials have been designed to determine the safety and efficacy of pharmacotherapy for patients with idiopathic pulmonary fibrosis (IPF). However, so far, only two drugs (pirfenidone and nintedanib) have been found to have an impact on disease progression as defined by reducing the rate of decline in forced vital capacity over a year among IPF patients with mild to moderate impairment in lung function. These two drugs have been approved for treatment of IPF by regulatory agencies and are currently in clinical use worldwide. This article summarises the current landscape of pharmacotherapy for IPF and highlights the prospects and potential of new therapies that are currently being pursued in clinical trials.

Concepts: Pharmacology, Pulmonology, Lung, Fibrosis, Idiopathic pulmonary fibrosis, Pulmonary fibrosis, Spirometry, Vital capacity