Category - Part 13
Bronchial Responsiveness in Children Exposed to Atmospheric Pollution in Hong Kong: Results
The mean (minimum and maximum) levels of SO2, NO2, RSP, and TSP (/лg/m) in ambient air in the two districts for the year 1989 to 1990 (September to June) as measured from fixed air monitoring stations situated in the two districts were as follows:
Kwai Tsing Southern
S02 117(72,177) 9( 4,16)
N02 40(31, 49) 21(15,26)
RSP 54(44, 68) 30(30,44)
TSP 94 (73, 133) 54 (43,70)
(Environmental Protection Department, Hong Kong Government). anti allergy
Bronchial Responsiveness in Children Exposed to Atmospheric Pollution in Hong Kong: Histamine Challenge Test
Consent for use of histamine challenge tests was obtained after submission of a proposal to the institution’s ethics committee.
The children received a bronchial challenge by histamine according to the method of Yan et al. Those children who had experienced an upper respiratory tract infection in the past 10 days with symptoms on the day of examination, confirmed by a physician, or whose FEVi was less than 60 percent of predicted, were excluded. The endpoint of the challenge was either a reduction of 20 percent or more of FEV i from baseline, or inhalation of the last dose of histamine. At the conclusion of the test, each child was examined for any respiratory discomfort, and nebulized salbutamol was given to any who had a reduction of 20 percent or more in FEV ь or if there was chest tightness Here zyrtec tablets. The FEV i was then measured at 2- to 3-min intervals until it returned to within 90 percent of the baseline.
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Bronchial Responsiveness in Children Exposed to Atmospheric Pollution in Hong Kong: Subjects
During the period January 1989 to December 1990, maximum daily levels of one or more of the following pollutants, sulfur dioxide (S02), nitrogen dioxide (N02), total suspended particulates (TSP), respirable suspended particulates (RSP), and ozone (O3), exceeded World Health Organization recommended standards on four occasions in KDT. No excess levels were reported for SDT.
Eleven schools, five in KDT and six in SDT, were recruited to participate in the respiratory health study. The method of sampling has been described elsewhere. Altogether, 3,513 children, 2,027 from KDT and 1,486 from SDT, were enrolled in the first year of the study in 1989 and examined from April to May. The prevalence of respiratory symptoms was higher in the KDT, but no differences were found in standard lung function tests (FEVi and FVC). In the second year (1990), the respiratory health inquiries were repeated in the same months.
Bronchial Responsiveness in Children Exposed to Atmospheric Pollution in Hong Kong
There is strong evidence of an association between atmospheric pollution, especially that produced by oxides of sulphur and nitrogen, ozone, and suspended particulates, and respiratory symptoms in exposed populations. There is concern that children exposed to these pollutants might be adversely affected in terms of their growth potential or predisposed to respiratory diseases during childhood and in later life. Although there is evidence to show that passive smoking is associated with impairment of pulmonary function and respiratory health in susceptible children, similar studies in children exposed to atmospheric pollution have been inconclusive.’ There is some experimental evidence to show that pollutants, such as oxides of nitrogen and ozone, increase bronchial reactivity (BR) in exposed individuals. Studies in adults with occupational or experimental exposure to various atmospheric pollutants have shown an association with faster deterioration of pulmonary function with age and a higher degree of BR. Continue reading this post…
Hemodynamic and Oxygen Transport Characteristics of Common Ventilatory Modes: Recommendation
The V02 decreased only on PSV of 5 cm H20. Furthermore, mean inspiratory flow increased and the duty cycle decreased significantly with increasing level of PSV. Fassoulaki and Eforakopoulou compared pressure support levels of 0,7,14, and 21 cm H2O for 1 h each in patients with respiratory failure and during postoperative period. With increasing level of PSV, f declined but Vt and mean airway pressure increased progressively. No change in РаОг, РаСОг, V02, and Vcc>2 were observed. In another study, Tokioka and colleagues applied levels of PSV to patients with severe respiratory failure necessary to achieve similar peak airway pressures reached while on ACV mode. They then decreased the level of pressure support gradually to the lowest level allowing regular breathing pattern and an f less than 20 breaths/ min. The data obtained after 30 min on an unspecified level of PSV showed an increase in Vt but lower f and Ve on PSV compared with ACV. Peak airway pressure and the duty cycle were lower, and РаОг was higher on PSV. Canadian health&care mall in detail No differences in mean inspiratory flow, inspiratory work, and V02 were noted. Dries and associates compared PSV levels of 10,20, and 30 cm H2O with SIMV rate of 8 during the postoperative period in patients undergoing coronary artery bypass grafting. All patients were on 5 cm H2O of PEEP. Data obtained after 20 min on each mode showed no differences in hemodynamic parameters between SIMV and PSV of 30 cm H2O. As the level of pressure support decreased, heart rate, mean arterial pressure, PAOP, and central venous pressure increased. No change in SVR, PVR, and Cl were noted among various modes. While РаОг, РаСОг, and PVO2 increased on PSV, shunt fraction and V02 remained unchanged.
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Hemodynamic and Oxygen Transport Characteristics of Common Ventilatory Modes: Conclusion
The information comparing SIMV and ACV modes are conflicting. Opposite effects of SIMV on cardiac function’ and oxygen consumption have been reported. The SIMV can influence oxygen consumption as the result of increasing the oxygen cost of breathing by the respiratory muscles during spontaneous breathing activity. This, in turn, could be reflected in the frequency of spontaneous breaths while on SIMV and possibly in the respiratory muscle mass that has to be moved to achieve spontaneous breaths. Analyzing the data in each individual patient on SIMV vs ACV modes, we could not detect any parallel correlation between the change in V02I and parameters such as spontaneous breathing frequency, Ve, or body mass index. In all patients, except one, however, the direction of change in V02I from ACV to SIMV was parallel to the change in TO2I. Canadian family pharmacy Link This linear correlation between V02I and TO2I in our patient population may reflect the pathologic dependency between these two parameters which is a well-recognized phenomenon in various disease states.” Alternatively, this correlation could be the result of the mathematical coupling of variables determining V02I and TO2I, or it could be related to the increased metabolic demands while on SIMV mode.
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Hemodynamic and Oxygen Transport Characteristics of Common Ventilatory Modes: Discussion
The SIMV mode has been promoted as a mean of positive-pressure ventilatory support with minimal effect on venous return by allowing ITP to decrease during the spontaneous inspiratory efforts. Previous studies had suggested that in normal individuals and in those with ventricular dysfunction the steady state cardiac output is not different on SIMV as compared with positive-pressure ventilation with matched ventilatory parameters. Our study shows that SIMV by allowing lower peak and mean airway pressures throughout the respiratory cycle tends to increase Cl compared with the ACV mode, although the differences are only of borderline significance and of questionable clinical importance. Canadian family pharmacy read We show, in addition, that the PSV mode tends to affect MIP and Cl in the same manner as does the SIMV mode, although to a lesser extent. Our study is in agreement with previous reports that the magnitude of the effects of SIMV and PSV modes on Cl are small, such that although there was a trend toward higher oxygen transport and consumption on these modes compared with the ACV mode (Table 4) the differences did not reach statistical significance.
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