Pregnancy is a normal but altered physiologic state that results in significant hormonal,mechanical, and circulatory changes. The increases in progesterone and estrogen associated with pregnancy contribute to vascular and central nervous system effects, changes in the balance of bronchoconstrictor and bronchodilator prostanoids, and increases in peptide hormones that alter connective tissue cha...

To determine whether initial lung volume optimization influences respiratory mechanics, which could indicate the achievement of optimal volume, we studied 17 premature infants with respiratory distress syndrome (RDS) assisted by high-frequency oscillatory ventilation. The continuous distending pressure (CDP) was increased stepwise from 6-8 cmH2O up to optimal CDP (OCDP), i.e., that allowing goo...

Ten intubated neonates (weights 0.90 to 2.58 kg) recovering from respiratory disease had lung mechanics, respiratory patterns, and functional residual capacity measured at 0 cmH2O continuous positive airways pressure and then after application of serially increasing levels of external expiratory resistance. At an external expiratory resistance greater than 40 cmH2O/1 per second, there was a sig...

Organisms must accommodate oxygen delivery to developing tissues as body mass increases during growth. In insects, the growth of the respiratory system has been assumed to occur only during molts, whereas body mass and volume increase during the larval stages between molts. This decouples whole-body growth from the growth of the oxygen supply system. This assumption is derived from the observat...

An important aspect that must be assessed before ventilator weaning is compliance of the respiratory system, because mechanical ventilation weaning may be impaired by the patient’s poor pulmonary condition.1,2 Compliance of the respiratory system is defined as the slope of the pressure-volume curve or the volume variation per unit of pressure change. The lungs and chest are formed by tissue wit...

background: despite wide application of chromium in electroplating industry, the pulmonary effects of chronic exposure to this chemical have not been extensively studied and are subject of debate and controversy. this study was, therefore, undertaken to further address this issue.   methods: the study population consisted of a group of 15 workers with a history of past and present occupational ...

background respiratory syncytial virus (rsv) can cause acute respiratory infection (ari) in infants and young children. objectives this study was conducted to determine the incidence of rsv infection and its subgroups among children with ari. materials and methods a total of 100 throat samples were collected from hospitalized children with ari in different hospitals across the khuzestan provinc...

Methacholine airway responsiveness has been observed to be related to prechallenge level of pulmonary function; however, normal ranges of responsiveness for specific levels of lung function have not been reported. We examined methacholine airway responsiveness in relation to level of prechallenge pulmonary function in a sample of 547 middle-aged and elderly men who denied any history of respira...