Lung hyperinflation stimulates the release of inflammatory mediators in spontaneously breathing subjects

Lung hyperinflation up to vital capacity is used to re-expand collapsed lung areas and to improve gas exchange during general anesthesia. However, it may induce inflammation in normal lungs. The objective of this study was to evaluate the effects of a lung hyperinflation maneuver (LHM) on plasma cytokine release in 10 healthy subjects (age: 26.1 ± 1.2 years, BMI: 23.8 ± 3.6 kg/m²). LHM was performed applying continuous positive airway pressure (CPAP) with a face mask, increased by 3-cmH2O steps up to 20 cmH2O every 5 breaths. At CPAP 20 cmH2O, an inspiratory pressure of 20 cmH2O above CPAP was applied, reaching an airway pressure of 40 cmH2O for 10 breaths. CPAP was then decreased stepwise. Blood samples were collected before and 2 and 12 h after LHM. TNF-&#945;, IL-1&#946;, IL-6, IL-8, IL-10, and IL-12 were measured by flow cytometry. Lung hyperinflation significantly increased (P < 0.05) all measured cytokines (TNF-&#945;: 1.2 ± 3.8 vs 6.4 ± 8.6 pg/mL; IL-1&#946;: 4.9 ± 15.6 vs 22.4 ± 28.4 pg/mL; IL-6: 1.4 ± 3.3 vs 6.5 ± 5.6 pg/mL; IL-8: 13.2 ± 8.8 vs 33.4 ± 26.4 pg/mL; IL-10: 3.3 ± 3.3 vs 7.7 ± 6.5 pg/mL, and IL-12: 3.1 ± 7.9 vs 9 ± 11.4 pg/mL), which returned to basal levels 12 h later. A significant correlation was found between changes in pro- (IL-6) and anti-inflammatory (IL-10) cytokines (r = 0.89, P = 0.004). LHM-induced lung stretching was associated with an early inflammatory response in healthy spontaneously breathing subjects

Comparison of two questionnaires which measure the health-related quality of life of idiopathic pulmonary fibrosis patients

The objective of the present study was to determine if there is a health-related quality of life (HRQL) instrument, generic or specific, that better represents functional capacity dysfunction in idiopathic pulmonary fibrosis (IPF) patients. HRQL was evaluated in 20 IPF patients using generic and specific questionnaires (Medical Outcomes Short Form 36 (SF-36) and Saint George's Respiratory Questionnaire (SGRQ), respectively). Functional status was evaluated by pulmonary function tests, 6-min walking distance test (6MWDT) and dyspnea indexes (baseline dyspnea index) at rest and after exercise (modified Borg scale). There was a restrictive pattern with impairment of diffusion capacity (total lung capacity, TLC = 71.5 ± 15.6%, forced vital capacity = 70.4 ± 19.4%, and carbon monoxide diffusing capacity = 41.5 ± 16.2% of predicted value), a reduction in exercise capacity (6MWDT = 435.6 ± 95.5 m) and an increase of perceived dyspnea score at rest and during exercise (6 ± 2.5 and 7.1 ± 1.3, respectively). Both questionnaires presented correlation with some functional parameters (TLC, forced expiratory volume in 1 s and carbon monoxide diffusing capacity) and the best correlation was with TLC. Almost all of the SGRQ domains presented a strong correlation with functional status, while in SF-36 only physical function and vitality presented a good correlation with functional status. Dyspnea index at rest and 6MWDT also presented a good correlation with HRQL. Our results suggest that a specific instead of a generic questionnaire is a more appropriate instrument for HRQL evaluation in IPF patients and that TLC is the functional parameter showing best correlation with HRQL

Diferentes frações inspiradas de oxigênio em coelhos hipovolêmicos anestesiados com propofol e submetidos à ventilação mecânica

Avaliaram-se os efeitos do fornecimento de diferentes frações inspiradas de oxigênio (FiO²) em coelhos hipovolêmicos, anestesiados com infusão contínua de propofol e mantidos em ventilação controlada sobre os parâmetros respiratórios, hemogasométricos e hemodinâmicos. Foram utilizados 50 coelhos (Nova Zelândia), pesando 3,5&plusmn;0,3kg, distribuídos em 5 grupos: G100 (FiO²=1), G80 (FiO²=0,8), G60 (FiO²=0,6), G40 (FiO²=0,4) e G21 (FiO²=0,21), os quais receberam xilazina (1mg kg-1) e cetamina (15mg kg-1) pela via intramuscular. Transcorridos 20 minutos, foi administrado propofol (8mg kg-1 bolus e 0,5mg kg-1 min-1) e rocurônio (0,6mg kg-1 bolus e 0,6mg kg-1 h-1). Iniciou-se então, a ventilação mecânica no modo pressão controlada. Após 30 minutos, os animais foram submetidos à hipovolemia aguda, retirando-se sangue arterial (12mL kg-1). Os parâmetros foram mensurados 30 minutos após a indução anestésica (M0) e a cada dez minutos depois da exsanguinação (M1- M7). As variáveis foram submetidas à análise de variância seguida pelo teste de Tukey (PThe effects of several inspired oxygen fractions (FiO²) on the blood gases, respiratory and hemodynamic parameters in mechanical ventilation hypovolemic rabbits anesthetized with continuous infusion of propofol were evaluated. A total of 50 rabbits (New Zealand), weighing 3.5&plusmn;0.3kg, were divided into five groups: G100 (FiO²=1), G80 (FiO²=0.8), G60 (FiO²=0.6), G40 (FiO²=0.4) and G21 (FiO²=0.21), which received xylazine (1mg kg-1) and ketamine (15mg kg-1) intramuscularly. Exactly after 20 minutes, it was administered propofol (8mg kg-1 bolus and 0.5mg kg-1 min-1) and rocuronium (0.6mg kg-1 bolus and 0.6mg kg-1 h-1. Then, the mechanical ventilation by controlled pressure mode began. After 30 minutes, the animals underwent acute hypovolemia, withdrawing arterial blood (12mL kg-1). The parameters were measured 30 minutes after anesthetic induction (M0) and every ten minutes after exsanguination (M1-M7). The variables were subjected to analysis of variance followed by Tukey test (P<0.05). The values of PaO², SaO², PAO², AaDO² decreased as lower were the FiO². After the induction of hypovolemia, the variables CO, MAP, PaO², SaO², Vt, AaDO² decreased significantly. No change was noted in the parameters HR and PaCO². The FiO² of 0.8 and 1.0 proved to be the most suitable for maintaining stability, better ventilation and adequate gas exchange

Effects of proportional assisted ventilation on exercise performance in idiopathic pulmonary fibrosis patients

SummaryBackgroundPatients with idiopathic pulmonary fibrosis (IPF) present an important ventilatory limitation reducing their exercise capacity. Non-invasive ventilatory support has been shown to improve exercise capacity in patients with obstructive diseases; however, its effect on IPF patients remains unknown.ObjectiveThe present study assessed the effect of ventilatory support using proportional assist ventilation (PAV) on exercise capacity in patients with IPF.MethodsTen patients (61.2±9.2 year-old) were submitted to a cardiopulmonary exercise testing, plethysmography and three submaximal exercise tests (60% of maximum load): without ventilatory support, with continuous positive airway pressure (CPAP) and PAV. Submaximal tests were performed randomly and exercise capacity, cardiovascular and ventilatory response as well as breathlessness subjective perception were evaluated. Lactate plasmatic levels were obtained before and after submaximal exercise.ResultsOur data show that patients presented a limited exercise capacity (9.7±3.8mLO2/kg/min). Submaximal test was increased in patients with PAV compared with CPAP and without ventilatory support (respectively, 11.1±8.8min, 5.6±4.7 and 4.5±3.8min; p<0.05). An improved arterial oxygenation and lower subjective perception to effort was also observed in patients with IPF when exercise was performed with PAV (p<0.05). IPF patients performing submaximal exercise with PAV also presented a lower heart rate during exercise, although systolic and diastolic pressures were not different among submaximal tests. Our results suggest that PAV can increase exercise tolerance and decrease dyspnoea and cardiac effort in patients with idiopathic pulmonary fibrosis

Lymphatic fluctuation in the parenchymal remodeling stage of acute interstitial pneumonia, organizing pneumonia, nonspecific interstitial pneumonia and idiopathic pulmonary fibrosis

Because the superficial lymphatics in the lungs are distributed in the subpleural, interlobular and peribroncovascular interstitium, lymphatic impairment may occur in the lungs of patients with idiopathic interstitial pneumonias (IIPs) and increase their severity. We investigated the distribution of lymphatics in different remodeling stages of IIPs by immunohistochemistry using the D2-40 antibody. Pulmonary tissue was obtained from 69 patients with acute interstitial pneumonia/diffuse alveolar damage (AIP/DAD, N = 24), cryptogenic organizing pneumonia/organizing pneumonia (COP/OP, N = 6), nonspecific interstitial pneumonia (NSIP/NSIP, N = 20), and idiopathic pulmonary fibrosis/usual interstitial pneumonia (IPF/UIP, N = 19). D2-40+ lymphatic in the lesions was quantitatively determined and associated with remodeling stage score. We observed an increase in the D2-40+ percent from DAD (6.66 ± 1.11) to UIP (23.45 ± 5.24, P = 0.008) with the advanced process of remodeling stage of the lesions. Kaplan-Meier survival curves showed a better survival for patients with higher lymphatic D2-40+ expression than 9.3%. Lymphatic impairment occurs in the lungs of IIPs and its severity increases according to remodeling stage. The results suggest that disruption of the superficial lymphatics may impair alveolar clearance, delay organ repair and cause severe disease progress mainly in patients with AIP/DAD. Therefore, lymphatic distribution may serve as a surrogate marker for the identification of patients at greatest risk for death due to IIPs