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1.
目的 探讨手工缝合肺残面方法肺减客手术治疗重度慢性阻塞性肺气肿的疗效。方法 本组肺减容手术20例,其中双侧肺减容6例,单侧肺减容14倒。切口的选择依据手术切除靶区的位置,其中平卧位正中切口、双侧LVRS1例,侧卧住后外侧开胸LVRS14侧,前外侧开胸LVRS11侧。术前及术后6月查肺功能(FEV1,TLC,RV)、动脉血气分析、6分钟步行距离进行对比。结果 本组无手术死亡,患者术后肺功能指标比术前有明显改善(P〈0.05),动脉血氧分压术后比术前明显提高(P〈0.05),二氧化碳分压术后比术前明显降低(P〈0.05);呼吸困难指数再分级,15例术前3级中6例转为1级,9例转为2级;5例4级中1例转为3级,3例转为2级,1例转为1级。结论 重度肺气肿病人行肺减容手术,能改善患者肺功能,提高生活质量。  相似文献   

2.
We evaluated the respiratory functions of patients with pulmonary emphysema who underwent lung volume reduction surgery (LVRS) by the mean transit time (MTT) with Xe-133 lung ventilation scintigraphy, forced expiration volume in 1 sec (FEV1.0), residual volume (RV), distance walked in 6 min (6-min walk), and the Hugh-Jones classification (H-J classification) before and after LVRS. In 69 patients with pulmonary emphysema (62 men, 7 women; age range, 47-75 years; mean age, 65.4 years +/- 6.1, preoperative H-J classification, III (two were II)-V) who underwent LVRS, all preoperative and postoperative parameters (MTT 3 weeks after LVRS and the others 3 months after LVRS) were judged statistically by the Wilcoxon signed-ranks test and Odds ratio. Every postoperative parameter was improved with a significant difference (P < 0.05) compared to preoperative parameters. MTT at 3 weeks after LVRS was not associated with %FEV1.0 and the H-J classification at 3 months after LVRS, but was associated with RV and a 6-min walk at 3 months after LVRS. MTT was useful for the clinical evalution of aerobic capability after LVRS.  相似文献   

3.
Effect of lung volume reduction surgery for emphysema on diaphragm function   总被引:1,自引:0,他引:1  
Preoperative prediction of a successful outcome following lung volume reduction surgery (LVRS) for emphysema is imperfect. One mechanism could be improvement in respiratory muscle function yet controversy exists regarding the magnitude and mechanism of such an improvement. Therefore, we measured diaphragm strength in 18 patients before and after LVRS. Mean (S.D.) FRC fell from 6.53 to 5.40 l (p = 0.0001). Mean sniff transdiaphragmatic pressure increased from 76 to 87 cm H2O (14%, p < 0.03) and mean twitch transdiaphragmatic pressure (Tw Pdi) increased by 2.5 cm H2O at 3 months (12%, p = 0.03). There was a highly significant increase in twitch esophageal pressure (Tw Pes) (60%, p < 0.0001), which was maintained at 12 months (46% increase, p = 0.0004). No change was observed in quadriceps twitch tension in nine subjects in whom it was measured. After LVRS the ratio Tw Pes:Tw Pdi increased from 0.24 to 0.37 at 3 months (p = 0.0003) and 0.36 at 12 months (p = 008). Low values of Sn Pdi, Sn Pes, Tw Pes and a high RV/TLC ratio were the preoperative variables most predictive of improvement in shuttle walking distance. We conclude that LVRS improves diaphragm function primarily by alteration of lung volume. Patients with poor diaphragm function and high RV/TLC ratio preoperatively are most likely to benefit from the procedure.  相似文献   

4.
In patients affected by chronic obstructive pulmonary disease (COPD), cardiopulmonary response to exercise was never related to the severity of emphysema (E) measured by high resolution computed tomography (HRCT). Sixteen patients (age=65±8 yrs; FEV(1)=54±18%pred; RV=160±28%pred) with moderate to severe E (quantified by lung HRCT as % voxels <-910 HU) were exercised on a cycle-ergometer to exhaustion. Oxygen uptake (V˙(O2)), carbon dioxide output (V˙(CO2)), ventilation (V˙(E)), tidal volume (V(T)), and end-tidal P(CO2) (PET(CO2)) derived variables were measured breath-by-breath. The % of E correlated with: (1) the ratio V(Tpeak) (r=0.74; p=0.001); (2) the V˙(E)/V˙(CO2) slope (r=-0.77; p=0.0004); (3) PET(CO2) values at peak exercise (r=0.80; p=0.0001). Also, the %E was strongly predicted by the following exercise equation: %E(EST) = 58.1 + 11.9 × ΔV˙(E)/V˙(CO2) (r=0.94; p<0.0001). A V(Tpeak)/FEV1 ratio>1 is typically observed in severe E patients; furthermore, the V˙(E)/V˙(CO2) slope and the PET(CO2peak) values decrease and increase respectively as more as the emphysema is severe.  相似文献   

5.
STUDY OBJECTIVES: While obesity is the most common risk factor for the development of obstructive sleep apnea, the correlation between measures of obesity and apnea severity is only moderate. We thus attempted to identify anatomic and physiologic predictors of apnea severity. DESIGN: We combined a careful assessment of upper airway anatomy, upper airway physiology, and ventilatory control in a group of obese individuals to identify predictors of apnea severity. Setting: Tertiary care academic medical center. PATIENTS: 14 morbidly obese subjects being evaluated for weight-reduction surgery. INTERVENTIONS: N/A MEASUREMENT AND RESULTS: We found no relationship between obesity (weight or body mass index) and apnea severity (respiratory disturbance index, RDI). However, those with severe apnea (RDI > 30) were found to have higher peak genioglossus EMG (GGEMG) (23.5 +/- 1.9 vs. 14.1 +/- 3.7 %max, p = 0.05) and greater airway collapsibility during pulses of negative pressure (7.6 +/- 0.9 vs. 4.4 -/+/-0.7 cmH2O, p =0.02). Airway collapsibility was significantly associated with RDI (r = 0.62, p < 0.01) as was peak GGEMG (r = 0.55, p < 0.05). Of the anatomic variables airway shape (A-P/lateral ratio) and volume change of the pharyngeal airway between total lung capacity and residual volume were different between those with and without severe apnea. Both correlated with RDI (A-P/lateral ratio: r = 0.70, p < 0.01 and volume change: r = 0.77, p < 0.01). CONCLUSIONS: We believe these findings suggest that specific anatomic and physiologic properties of the airway interact with obesity to predispose to the development of airway collapse during sleep.  相似文献   

6.
The mechanism by which inhaled smoke causes the anatomic lesions and physiologic impairment of chronic obstructive pulmonary disease remains unknown. We used high-density microarrays to measure gene expression in severely emphysematous lung tissue removed from smokers at lung volume reduction surgery (LVRS) and normal or mildly emphysematous lung tissue from smokers undergoing resection of pulmonary nodules. Class prediction algorithms identified 102 genes that accurately distinguished severe emphysema from non-/mildly emphysematous lung tissue. We also defined a number of genes whose expression levels correlated strongly with lung diffusion capacity for carbon monoxide and/or forced expiratory volume at 1 s. Genes related to oxidative stress, extracellular matrix synthesis, and inflammation were increased in severe emphysema, whereas expression of endothelium-related genes was decreased. To identify candidate genes that might be causally involved in the pathogenesis of emphysema, we linked gene expression profiles to chromosomal regions previously associated with chronic obstructive pulmonary disease in genome-wide linkage analyses. Unsupervised hierarchical clustering of the LVRS samples revealed distinct molecular subclasses of severe emphysema, with body mass index as the only clinical variable that differed between the groups. Class prediction models established a set of genes that predicted functional outcome at 6 mo after LVRS. Our findings suggest that the gene expression profiles from human emphysematous lung tissue may provide insight into pathogenesis, uncover novel molecular subclasses of disease, predict response to LVRS, and identify targets for therapeutic intervention.  相似文献   

7.
Lung function and bronchoalveolar lavage (BAL) fluid are commonly analyzed to assess the severity of lung disease in sacrificed animals. The input impedance of the respiratory system (Z(rs)) was measured and BAL fluid was collected in intubated, anesthetized, mechanically ventilated rats on three occasions 1 week apart. Measurements were performed in control animals (group C), while lung injury was induced in the other group (group LPS) by i.p. injection of lipopolysaccharide (LPS) before the second measurement. The airway resistance (R(aw)), tissue damping (G) and elastance (H) were determined from the Z(rs) spectra. The total cell counts (TC) from 0.3- to 0.4-ml BAL fluid were also determined. R(aw) exhibited no significant change in either group C (-6.7+/-3.6[S.E.]%) or LPS (-0.9+/-3.7%). Reproducible G and H values were obtained in group C (2.5+/-5.3%, -7.0+/-4.4%), while G and H increased in group LPS (18.4+/-6.5%, 14.9+/-13.8%, p<0.05). The changes in TC followed a similar pattern to those observed in G, with no change in group C (-7.9+/-30%), but with a marked increase in group LPS (580+/-456%, p<0.05). The method devised for repeated BAL measurements in another group of rats without intubation and muscle relaxant resulted in similar results in BAL profile. We conclude that longitudinal follow-up of the airway and tissue mechanics and inflammatory cells in the BAL fluid are feasible in rats. The current method allows an early detection of lung injury, even in a relatively mild form.  相似文献   

8.
Some patients with lung disease retain CO(2), while others with similar lung function do not. This could be explained if CO(2) retainers had a pre-existing low hypercapnic ventilatory response (HCVR) and, from this, a tendency to retain CO(2). To test if such a phenomenon exists in healthy people, we determined the change in end-tidal P(CO(2)) (deltaPET(CO(2))) produced by the addition of a dead-space (DS), during wakefulness and sleep, and related this to the HCVR measured awake. The group mean (n=14) HCVR slope was 2.2+/-1.1 (S.D.) L min(-1) mmHg(-1). The deltaPET(CO(2)) with the application of DS was 1.6+/-1.6 mmHg awake and 2.6+/-2.2 mmHg asleep. During wakefulness the deltaPET(CO(2)) with DS did not correlate with the HCVR slope. However, during sleep, four subjects had a marked increase in the deltaPET(CO(2)) (3.7, 4.3, 6.2, 8.0 mmHg) and a relatively low HCVR (slope 1.5, 1.7, 1.5, 1.7 L min(-1) mmHg(-1), respectively). We speculate that such individuals, should they develop lung disease, may be predisposed to retain CO(2).  相似文献   

9.
In severe emphysema, lung volume reduction surgery (LVRS) can improve lung function and exercise tolerance. The maximal changes of forced expiratory volume in 1s (FEV(1)) and lung volume occur early after surgery, whereas maximal improvement of exercise tolerance occurs later. We tested the hypothesis that secondary adaptation of inspiratory muscles could explain this delayed clinical improvement. In that purpose, we evaluated nine consecutive patients before LVRS and up to 9 months post-operatively. Six weeks after LVRS, we observed an increase in FEV(1) and 6 min walk distance (6MWD). The gain in sniff nasal inspiratory pressure (SNIP) was inversely proportional to lung volume loss. Values of FEV(1) and lung volume were maintained throughout follow-up whereas SNIP values significantly increased from 6 weeks to 6 months post-LVRS. In the meantime, we observed an increase in 6MWD correlated with the SNIP increase. This suggests that in patients undergoing LVRS, early improvement of SNIP is proportional to decrease in lung volume whereas the further delayed improvement may be due, at least in part, to adaptation of the inspiratory muscles.  相似文献   

10.
To evaluate whether respiratory factors limit exercise capacity in patients with mild cystic fibrosis (CF) lung disease (mean FEV(1) = 76 +/- 7.7% predicted) we stressed the respiratory system of seven patients using added dead space (V(D)). Primary outcomes were exercise duration (Ex(dur)) and maximal oxygen uptake (VO(2max)). Dyspnoea/leg-discomfort were assessed at end-exercise. Ex(dur) was identical between control and V(D) studies (520 +/- 152 versus 511 +/ -166 s, p = NS) as was VO(2max)(1.6 +/- 0.5 versus 1.6 +/- 0.6 L/min, p = NS). Significant resting, sub-maximal and maximal workload increases in minute ventilation (V(E)) were detected (70.8 +/- 13.7 versus 79.5 +/- 16.9 L/min, p < 0.05). Analysis of breathing pattern revealed increases in V(E) were attributable to increases in tidal volume (2.0 +/- 0.5 versus 2.2 +/- 0.6 L, p < 0.05) with no change in respiratory frequency. There was no difference in dyspnoea/leg discomfort between tests. The increase in V(E) in response to V(D), with no change in [Exdur/VO(2max) suggests maximal symptom-limited exercise limitation is not primarily limited by respiratory factors in mild CF lung disease. Focused investigation and treatment of non-respiratory factors contributing to exercise limitation may improve exercise rehabilitation in this patient group.  相似文献   

11.
We applied a novel head-out plethysmographic (HOP) method to study awake canine responses to external resistive loading and natural laryngeal paralysis. Measurements of inspiratory and expiratory specific airway resistance (sRaw(insp), sRaw(exp)) were obtained before and after uni- and bidirectional loading (R(add) = 5 cmH(2)O/L/s) in large-breed dogs (n = 9). Mean sRaw(insp) after inspiratory, and sRaw(exp) after expiratory loading were 31.4 and 33.3 cmH(2)Os, respectively. Bidirectional loads induced a significantly greater rise in both sRaw(insp) and sRaw(exp) (55.1 and 61.3 cmH(2)Os) compared to unidirectional loading (P < 0.001). Yet, type of loading did not affect flow-volume indices. The mean R(aw) of dogs was 4.81 cmH(2)O/L/s. Expiratory loading resulted in a significant 8.8% increase in functional-residual-capacity (FRC), compared to FRC(baseline) (76.7 ml/kg). Dogs (n = 5) with laryngeal paralysis demonstrated a significant increase in sR(aw) and R(aw) compared to controls without changes in FRC. In conclusion, HOP precisely characterized sR(aw) in response to external resistive loading. Hence, we could accurately quantify airway obstruction in awake dogs with laryngeal paralysis.  相似文献   

12.
Small human lung specimens are frequently used for cell biological studies of the pathogenesis of emphysema. In general, lung function and other clinical parameters are used to establish the presence and severity of emphysema/chronic obstructive pulmonary disease without morphological analysis of the specimens under investigation. In this study we compared three morphological methods to analyze emphysema, and evaluated whether clinical data correlate with the morphological data of individual lung samples. A total of 306 lung specimens from resected lung(lobes) from 221 patients were inflated and characterized using three morphological parameters: the Destructive Index, the Mean Linear Intercept, and Section Assessment. Morphological data were related to each other, to lung function data, and to smoking behavior. Significant correlations (P < .001) were observed between Section Assessment and Destructive Index (r = 0.92), Mean Linear Intercept with Destructive Index (r = 0.69) and Mean Linear Intercept with Section Assessment (r = 0.65). Section Assessment, being much less time consuming than Mean Linear Intercept and Destructive Index, is the parameter of choice for initial analysis. Destructive Index is the most sensitive parameter. There was a significant (P < .001), but weak correlation for all three parameters with the diffusion capacity for CO (K(CO)) (Destructive Index: r = -0.28; Mean Linear Intercept: r = -0.34; Section Assessment: r = -0.32), and with FEV(1)/IVC (Destructive Index: r = -0.29; Mean Linear Intercept: r = -0.33; Section Assessment: r = -0.28), but not with other lung function parameters. A significant difference (P < .05) between (ex-) smokers and never-smokers was observed for Destructive Index and Section Assessment. It is concluded that the application of the three morphological parameters represents a useful method to characterize emphysematous lesions in a (semi-)quantitative manner in small human lung specimens, and that Section Assessment is a suitable and fast method for initial screening. The extent of emphysema of individual lung specimens should be established by means of morphometry, rather than lung function data.  相似文献   

13.
PurposeCombined pulmonary fibrosis and emphysema (CPFE) has emerged as a new syndrome with characteristics of both fibrosis and emphysema. We determined the impacts of radiologic emphysema severity on pulmonary function tests (PFTs), exercise capacity and mortality.Patients and methodsIPF patients (n = 110) diagnosed at the Chest Diseases Clinic between September 2013 and January 2016 were enrolled in the study and followed up until June 2017. Visual and digital emphysema scores, PFTs, pulmonary artery pressure (sPAP), 6-minute walking test, composite physiologic index (CPI), and survival status were recorded. Patients with emphysema and those with pure IPF were compared.ResultsThe CPFE-group had a significantly greater ratio of men(p < 0.001), lower BMI (p < 0.001), lower mean PaO2 (p = 0.005), higher mean sPAP (p = 0.014), and higher exercise desaturation (p < 0.001). The CPFE group had a significantly higher FVC(L)(p = 0.016), and lower FEV1/FVC ratio (p = 0.002), DLCO, and DLCO/VA ratio(p = 0.03 and p = 0.005, respectively). Lung volumes of the CPFE group had significantly higher VC(p = 0.017), FRC (p < 0.001), RV(p < 0.001), RV/TLC(p < 0.001), and TLC(p < 0.001). There were significant correlations between emphysema scores and FVC (L)(p = 0.01), FEV1/FVC(p = 0.001), DLCO (p = 0.003), VC(p = 0.014), FRC (L)(p < 0.001), RV(p < 0.001), TLC(p < 0.001), and RV/TLC (p < 0.001). Mortality rates were comparable between the two groups. CPI (p = 0.02) and sPAP (p = 0.01) were independent predictors of mortality in patients with CPFE.ConclusionsThe presence and severity of emphysema affects pulmonary function in IPF. Patients with CPFE have reduced diffusion capacity, more severe air trapping, worse muscle weakness, more severe exercise desaturation, and pulmonary hypertension. CPI and pulmonary hypertension are two independent risk factors for mortality in subjects with CPFE.  相似文献   

14.
It has been demonstrated that airway deposition of inhaled aerosols is more heterogeneous in patients with asthma than in normal subjects. Nevertheless, the influence of abnormal airway deposition on responses to bronchoactive aerosols is poorly understood. We altered bronchopulmonary deposition heterogeneity of methacholine aerosol in nine asymptomatic patients with asthma by controlling inspiratory flow at high (approximately 60 L/min) versus low (approximately 12 L/min) rates on 2 study days and determined the effect on the provocative dose of methacholine causing a 20% fall in FEV1 (PD20) (often used as a measure of airway responsiveness). Deposition uniformity was quantified from gamma-camera scans of the lungs in terms of the distribution of a technetium-labeled aerosol that was inhaled rapidly or slowly before the inhalation of methacholine. Increased deposition in an inner (large, central airways) versus an outer (peripheral airways and alveoli) zone of the right lung (inner/outer ratio, greater than 1) and higher values of skew (an index of deposition asymmetry) and kurtosis (an index of deposition range) indicated enhanced heterogeneity of deposition. Mean (+/- SD) inner/outer ratio was significantly higher during rapid inspiration compared to slow inspiration with 2.91 +/- 0.51 and 1.84 +/- 0.30, respectively (p less than 0.01). Mean skew and kurtosis were also significantly higher after rapid inspiration, with 1.12 +/- 0.35 and 3.86 +/- 1.25, respectively, compared to 0.74 +/- 0.36 and 2.64 +/- 0.77 after slow inhalation (p less than 0.01). Geometric mean PD20 methacholine was significantly reduced when the aerosol was inhaled rapidly, with 5.9 cumulative methacholine units compared to 15.7 units after slow inhalation (p less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

15.
We investigated whether end-expiratory lung volume (EELV) or lung mechanical parameters are more sensitive for the detection of a compromised gas exchange during bronchoconstriction and after surfactant depletion. EELV was determined via SF(6) multiple breath wash-outs in mechanically ventilated rabbits while a positive end-expiratory pressure (PEEP) of 1, 3 or 7 cm H(2)O was maintained. Airway resistance (R(aw)) and parenchymal elastance (H) were estimated from the pulmonary input impedance measured at each PEEP level by means of forced oscillations. Measurements were repeated during i.v. methacholine (MCh) infusions and following lung injury induced by saline lavage. MCh induced marked elevations in R(aw), with no significant change in EELV or H at any PEEP. After lavage, the severity of hypoxia was reflected systematically in significant decreases in EELV at all PEEP levels (-42+/-13%, -26+/-4%, and -18+/-5% at 1, 3 and 7 cm H(2)O, respectively), whereas compromised gas exchange was not associated with consistent changes in the mechanical parameters at a PEEP of 7 cm H(2)O (20+/-9% and 14+/-9% in R(aw) and H, respectively; p=0.2). We conclude that R(aw) is the only sensitive indicator for the detection of a compromised lung function during MCh infusions, whereas the estimation of EELV is necessary to follow the progression of a lung injury when a high PEEP level is applied.  相似文献   

16.
The aim of this study is to propose a new approach to estimate non-invasively arterial carbon dioxide partial pressure (P(a)CO2) approach was based on the reconstruction of alveolar gas composition over each breath from a tidally ventilated lung model (P(M)(CO2)). Eight healthy young subjects were studied during a ramp exercise test on a cycle ergometer. Arterial samples were drawn at rest and every minute during the exercise test for determination of P(a)CO2 . P(a)CO2 was compared with indirect estimates of P(CO2) : P(M)(CO2), end-tidal P(CO2) (P(ET)(CO2)) and an empirical equation involving P(ET)(CO2) and tidal volume (P(J)(CO2)). The difference between estimated and measured P(a)CO2 on the whole ramp exercise was -0.3+/-1.9mmHg for P(M)(CO2), 1.0+/-2.2mmHg for P(ET)(CO2) and -1.7+/-1.7mmHg for P(J)(CO2) . P(ET)(CO2) and P(J)(CO2) were significantly different from actual P(a)CO2 (P<0.001). It is concluded that, on the basis of the bias, the breathing lung model gave better estimates of P(a)CO2 than the two other indirect methods during ramp exercise.  相似文献   

17.
In various cardio-pulmonary diseases lung mass is considerably increased due to intrapulmonary fluid accumulation, i.e. extravascular lung water (EVLW). Generally, inertance is a physical system parameter that is mass-dependent. We hypothesized that changes in lung mass influence the inertive behavior of the respiratory system. EVLW and intrathoracic blood volume (ITBV) were compared with respiratory system inertance (I(rs)) in four piglets before and after broncho-alveolar lavage (BAL) that induced surfactant deficiency with interstitial edema. EVLW and ITBV were determined using the double-indicator dilution technique, I(rs) by multiple linear regression analysis. Measurements were taken before, and 1 and 2 h after BAL. EVLW increased threefold (from 6.2+/-0.8 mL/kg at baseline to 17.7+/-0.9 mL/kg (p < 0.001) after BAL). I(rs) increased by 35% (from 0.17+/-0.02 to 0.23+/-0.04 cmH(2)O s(2)/L (p = 0.036) after BAL) and was tightly correlated to EVLW (r(2) = 0.95, p < 0.023). ITBV did not change significantly after BAL. We conclude that I(rs) reflects actual changes in lung mass and thus hints at fluid accumulation within the lung.  相似文献   

18.
目的探讨肺淋巴管平滑肌瘤病(pulmonarylymphangioleiomyomatosis,PLAM)临床和病理特征。方法对3例PLAM患者的临床资料、HE及免疫组化染色结果进行分析,并结合文献进行复习。结果PLAM是一种持续发展的弥漫性肺疾病。只发生在女性,特别是绝经前妇女。临床表现为反复发作的自发性气胸、活动后呼吸困难、咯血和乳糜胸等。高分辨率CT(HRCT)可见两肺弥漫性分布的薄壁小囊状改变。组织学特点为肺淋巴管、小气道、小血管的管壁及其周围的平滑肌细胞弥漫性异常增生。免疫组化结果显示3例均表达HMB-45、SMA、actin、MMP-2、desmin,2例表达PR、ER。经随访,有2例死亡。结论育龄期妇女发生渐进性呼吸困难,并反复出现气胸,胸部HRCT示两肺弥漫性分布薄壁囊状改变,临床上应考虑到PLAM的可能,最好能行肺组织活检明确诊断。PLAM在影像学与病理组织学上有特征性表现,免疫组化HMB-45阳性具特异性,预后较差。  相似文献   

19.
The effect of high-frequency oscillatory ventilation (HFOV) settings on the distribution of lung volume (V(L)) with changes in mean airway pressure (Paw), frequency (f(R)) and tidal volume (V(T)) remains controversial. We used computer tomographic (CT) imaging to quantify the distribution of V(L) during HFOV compared to static continuous positive airway pressure (CPAP). In anesthetized, supine canines, CT imaging of the entire lung was performed during CPAP and HFOV at Paw of 5, 12.5 and 20 cm H(2)O, f(R)=5, 10, 15 Hz. We found small, statistically significant decreases compared with CPAP in total and regional V(L) during HFOV that were greatest at lower f(R) and Paw. Apex and base sub-volumes underwent changes comparable to the lung overall. Increases in f(R) were accompanied by increases in Pa(O)(2). These finding provide additional insight into the impact of HFOV settings on the distribution of V(L) and suggest that there is low risk of occult regional over-distention during HFOV in normal lungs.  相似文献   

20.
BACKGROUND: The target of anti-inflammatory therapy in asthma is thought to be situated, at least partly, in the lung periphery, and inhaled steroid aerosols are being engineered to reach it. However, the potential effect of such aerosols cannot be fully evaluated by conventional lung function tests because these are insensitive to peripheral lung structure. OBJECTIVE: A prospective cohort study was conducted to investigate whether ultrafine steroid aerosols can elicit a response in the lung periphery, using a validated multibreath washout technique that can distinguish acinar from conductive lung zone function. METHODS: In 30 stable patients with asthma with a wide range of disease severity (FEV(1) 27% to 108% predicted), we assessed conductive and acinar airway function abnormality at baseline, with patients on a standard dry powder steroid aerosol and after switching them to an ultrafine steroid aerosol. RESULTS: Only in those patients with abnormal acinar airway function at baseline (n = 16) did acinar heterogeneity show a consistent improvement after switching to an ultrafine steroid aerosol; the improvement was also correlated with baseline acinar heterogeneity (r = -0.67; P = .007). Although all patients with asthma also presented conductive airway abnormality at baseline, no changes were observed in this lung zone with the switch to the ultrafine aerosol (P > .1). CONCLUSION: Among stable patients with asthma, those with acinar lung zone abnormality at baseline have the potential to receive functional benefit from an ultrafine steroid aerosol. Clinical studies comparing the efficacy of steroid aerosols targeted to the deep lung should at least include a measurement of peripheral lung zone function. CLINICAL IMPLICATIONS: A new noninvasive measure of small airways function reveals why, and for which particular patients with asthma, small steroid aerosol particles can be of therapeutic use.  相似文献   

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