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Category Archives: ARDS

Computed Tomography in Established Adult Respiratory Distress Syndrome: Conclusion

Computed Tomography in Established Adult Respiratory Distress Syndrome: ConclusionFurthermore, only the radiographic and hypoxemia scores were calculated at the LIS at the second study point, as all the patients were self-ventilating. This influence on the statistical relationship, however, is unlikely to be important as the cross-sectional nature of CT provides a different and more precise depiction of the extent of pulmonary abnormalities compared with two-dimensional chest radiographs.
As ARDS evolves in survivors, functional recovery is most rapid in the first 6 months and reaches a plateau 1 year after the onset. A reduced carbon monoxide diffusing capacity is the most common abnormality of lung function, being reported in 7 of 16 nonsmokers at 1 year. Reductions of carbon monoxide diffusing capacity are often still apparent even when corrected for alveolar volume, suggesting that the most important defect is a loss of pulmonary capillary surface area. Reading here

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Computed Tomography in Established Adult Respiratory Distress Syndrome: Comment

A chronic, third phase of ARDS occurs in survivors. The early histopathologic features of this stage may be detectable as early as 3 to 7 days postinjury; these are characterized by hyperplasia of type 2 pneumo-cytes, fibroblastic infiltration, and deposition of connective tissue. At this stage, the high permeability pulmonary edema begins to regress. Continuing physiologic impairment is probably the consequence of decreased tissue compliance, V/Q imbalance, diffusion impairment, and destruction of the mi-crovascular bed.
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Computed Tomography in Established Adult Respiratory Distress Syndrome: Treatment

Computed Tomography in Established Adult Respiratory Distress Syndrome: TreatmentIt seems reasonable to expect such variation in view of the considerable time period that elapsed between the onset of the disease and the first CT, although no formal relationship between this delay and the degree of ground-glass opacification could be established, probably because the radiologic features of ARDS are frequently modified according to the nature of precipitating event and the complications of supportive therapy. This seems unlikely to be the whole explanation, however, as several of our study population still had evidence of such appearances in convalescence (Table 3).
The second stage of ARDS is a direct consequence of the increased pulmonary vascular permeability that characterizes the condition. Ultrastructural changes are evident in both the alveolar epithelium and the capillary endothelium. so

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Computed Tomography in Established Adult Respiratory Distress Syndrome: Discussion

All patients had an LIS in excess of 2.5 on admission to our ICU, but this had fallen to 1.72 ±0.14 at the time of the initial scan (Table 1). Mean LIS at follow-up was 0.6 ±0.17. There was a significant correlation between the extent of CT abnormalities and LIS for all time points (r=0.75, p<0.01).
We have shown that the CT changes observed in patients with ARDS who survive are variable in extent and character and change considerably over time as the disease resolves. Moreover, the morphologic and functional abnormalities observed in this in certain diffuse lung diseases, particularly those involving fibrosis. The patients in our population were considered too unwell to tolerate open lung biopsy to allow pathologic correlation with the CT findings. generic for doxycycline

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Computed Tomography in Established Adult Respiratory Distress Syndrome: Results

Computed Tomography in Established Adult Respiratory Distress Syndrome: ResultsComputed tomographic abnormalities identified on the initial and follow-up scans are summarized in Tables 2 and 3. The presence or absence of the five categories of disease was recorded for the initial scan. These were ground-glass opacification (8/8), parenchymal distortion (8/8), multifocal areas of consolidation (6/8), reticular opacities (6/8), and linear opacities (5/8). Bilateral pleural effusions were present in two patients and unilateral effusions were present in three. Small, shallow, bilateral anterior pneumothoraces were present in two patients and unilateral pneumothoraces were present in three. On the subsequent CT scans, the multifocal areas of consolidation had resolved in all cases. Ground-glass opacification persisted in four of eight (Fig 1), although the extent and severity was less marked than in the acute phase.

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Computed Tomography in Established Adult Respiratory Distress Syndrome: Data Analysis

The outlines of the lungs at the five CT levels were traced onto paper; these were cut out and weighed using an electronic balance. The ratios of the weights (and thus the lung volumes) for the five levels were (mean ± SD) as follows: level 1=0.129 ±0.017; level 2=0.190 ±0.011; level 3=0.222 ±0.008; level 4=0.228 ±0.009; and level 5=0.230 ± 0.015. The mean of the percentage of abnormal lung estimated by the two observers at each level was multiplied by the corresponding ratio. Adding the five adjusted figures gave an estimation of the overall percentage volume of abnormal lung. purchase zyrtec

Data are presented in the text as mean±SEM except where otherwise stated. The percentage of persistently abnormal lung at both initial scan and follow-up was correlated with the LIS using linear regression analysis. A p value less than 0.05 was considered significant.
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Computed Tomography in Established Adult Respiratory Distress Syndrome: Protocol

Computed Tomography in Established Adult Respiratory Distress Syndrome: ProtocolAll patients were treated in the ICU using modes of mechanical ventilation, an FIO2, and inotropic agents sufficient to produce an oxygen delivery index of 300 mL/min/m2 birth control.

The initial CT scan was performed as soon as the patient could be transferred safely to the CT scanning unit in a mechanically ventilated state. An LIS was performed immediately before the patient leaving the ICU for CT scanning. The scan was repeated as soon as possible after each patient was discharged from hospital and became fully ambulatory. A second LIS was performed on the same day as the CT scan using a standard chest radiograph and arterial gas analysis (Corning 170 blood gas analyzer, Corning UK, Essex).

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Computed Tomography in Established Adult Respiratory Distress Syndrome: Investigations

The records and scans of eight patients (three male; mean age, 30 years; range, 15 to 59 years) were examined (Table 1). Five patients presented after trauma sustained in road traffic accidents, one after an abdominal operation, one after cardiotho-racic surgery, and one patient after a severe pneumococcal pneumonia. At the time of entry into the study, each patient fulfilled the diagnostic criteria for ARDS used in our unit: an antecedent history of a precipitating condition, changes on chest radiograph suggestive of pulmonary edema, and a ratio of PaC>2:FI02 of <150 mm Hg (20 kPa) in the presence of normal plasma proteins and a pulmonary artery occlusion pressure <15 mm Hg.
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Computed Tomography in Established Adult Respiratory Distress Syndrome: Methods and Materials Patient Population

Computed Tomography in Established Adult Respiratory Distress Syndrome: Methods and Materials Patient PopulationThe adult respiratory distress syndrome (ARDS) is characterized by refractory hypoxemia secondary to nonhydrostatic pulmonary edema and is associated with a wide variety of precipitating factors, many not directly involving the lung. Mortality has remained almost unchanged since the syndrome was first described in 1967. However, much is now known about the pathophysiology of the condition: histopathologic examination of tissue obtained from patients with ARDS suggests that the condition evolves through exudative, inflammatory, and fibro-proliferative phases Reading here.
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Cardiorespiratory Effects of Pressure-controlled Ventilation With and Without Inverse Ratio in the Adult Respiratory Distress Syndrome: Conclusion

Cardiorespiratory Effects of Pressure-controlled Ventilation With and Without Inverse Ratio in the Adult Respiratory Distress Syndrome: ConclusionIn fact, the lack of improvement in P&02 with PC-IRV may be more simply related to the decrease in Pv02 observed with this mode as a consequence of the reduction in CO. Indeed, reduced Pv02 may adversely affect arterial oxygenation in pulmonary disease with profound ventilation/perfusion inequalities, such as ARDS.
We observed a significant decrease in PaC02 with PC-IRV Such a finding is in accordance with the results of previous studies reporting a decrease in physiologic dead space induced by prolonged inspiratory time. This decrease in BaC02 with PC-IRV could permit a reduction in Vt in order to obtain the same level of PaC02 as in VCV. Such a reduction would probably lower the rise in mPaw observed in PC-IRV
In accordance with previous studies, PCV and expecially PC-IRV induced lower pPaw than VCV did. Such a finding is usually seen as beneficial in terms of barotrauma; however, studies in animals demonstrated that the occurrence of barotrauma is linked to lung volumes rather than to airway pressures per se. Therefore, peak static alveolar pressure (ie, Pplat) is probably more relevant than peak dynamic pressure (ie, pPaw) to assess the risk of barotrauma. We did not observe any decrease in Pplat with PCV and PC-IRV Therefore, the reduced risk of barotrauma consequent to the decreased pPaw observed in these ventilatory modes is questionable. On the other hand, as discussed earlier, PC-IRV may allow a reduction in Vt which might reduce barotrauma.
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