Body Position Changes Redistribute Lung Computed-Tomographic Density in Patients with Acute Respiratory Failure

Gattinoni, Luciano; Pelosi, Paolo; Vitale, Giovanni; Pesenti, Antonio; D’Andrea, Luca; Mascheroni, D.

doi:10.1097/00000542-199101000-00004

Cited by 552 publications

(290 citation statements)

References 0 publications

Supporting

Mentioning

253

Contrasting

Unclassified

Order By: Relevance

“…ALI/ARDS produces a diffuse lung injury that is mechanically heterogeneous at risk for further injury. Specifically, when supine, the reduced volume of the nondependent aerated lung is at risk for alveolar overdistention with conventional ventilator strategies while the interaction of cyclic ventilation and lung injury causes repetitive recruitment and de-recruitment with consequent biomechanical strain in dependent lung regions (7).…”

mentioning

confidence: 99%

Clinical trial design—effect of prone positioning on clinical outcomes in infants and children with acute respiratory distress syndrome

Curley

Arnold

Thompson

et al. 2006

Journal of Critical Care

View full text Add to dashboard Cite

Purpose-This paper describes the methodology of an ongoing clinical trial of prone positioning in pediatric patients with acute lung injury (ALI). Nonrandomized studies suggest that prone positioning improves oxygenation in patients with ALI/ARDS without the risk of serious iatrogenic injury. It is not known if these improvements in oxygenation result in improvements in clinical outcomes. A clinical trial was needed to answer this question. Materials and Methods-The pediatric prone study is a multi-center, randomized, non-crossover, controlled clinical trial. The trial is designed to test the hypothesis that at the end of 28 days, children with ALI treated with prone positioning will have more ventilator free days than children treated with supine positioning. Secondary endpoints include the time to recovery of lung injury, organ failure free days, functional outcome, adverse events, and mortality from all causes. Pediatric patients, 42 weeks post-conceptual age to 18 years of age, are enrolled within 48 hours of meeting ALI criteria. Patients randomized to the prone group are positioned prone within 4 hours of randomization and remain prone for 20 hours each day during the acute phase of their illness for a maximum of 7 days. Both groups are managed according to ventilator protocol, extubation readiness testing, and sedation protocols and hemodynamic, nutrition and skin care guidelines.

show abstract

mentioning

confidence: 99%

Clinical trial design—effect of prone positioning on clinical outcomes in infants and children with acute respiratory distress syndrome

Curley

Arnold

Thompson

et al. 2006

Journal of Critical Care

View full text Add to dashboard Cite

show abstract

“…As shown, a greater part of the lung parenchyma would be always kept open through the respiratory cycle compared to a lower PEEP model (gray), while the lung region undergoing intra-tidal opening and closing (light blue) should be reduced dependent ones (sternal), even if they are edematous, remain inflated [33]. If the patient is positioned prone, the verterbral lung regions become non-dependent and re-inflate, while the sternal ones become dependent and collapse [20]. PEEP (positive end-expiratory pressure) works by overcoming the superimposed pressure and keeping open whatever lung region had been opened during the previous inspiration [21].…”

Section: High Peep Mechanismsmentioning

confidence: 99%

Does high PEEP prevent alveolar cycling?

Cressoni

Chiurazzi

Chiumello

et al. 2017

Med Klin Intensivmed Notfmed

View full text Add to dashboard Cite

“…Another variable that may be important when setting mechanical ventilation is the superimposed pressure [12,13]. This parameter represents the hydrostatic pressure that develops into the lung parenchyma from the nondependent to the dependent regions.…”

Section: à Volume Of Tissuementioning

confidence: 99%

“…The difference lies in the amount of the recruitable lung, which represents, in essence, the portion of lung tissue that is collapsed and capable of being opened. Lung collapse, then, is likely to be a function of the gravity-dependent compressive forces (the superimposed pressure) generated by the increased lung mass (ie, lung edema) [13,15,23]. Indeed, a possible model of ARDS pathophysiology may include an equally represented portion of core disease (the ''consolidated'' lung tissue), for instance a regional pneumonia.…”

mentioning

confidence: 99%

The Role of CT-scan Studies for the Diagnosis and Therapy of Acute Respiratory Distress Syndrome

Gattinoni

Caironi

Valenza

et al. 2006

Clinics in Chest Medicine

Self Cite

View full text Add to dashboard Cite

The radiologic assessment of lung infiltrates by conventional anterior-posterior chest radiographs has been embedded in the concept of acute respiratory distress syndrome (ARDS) since its original description by Ashbaugh and colleagues [1]. In fact, the presence of bilateral lung infiltrates as detected by chest radiograph, in association with ''refractory'' hypoxemia and impaired mechanics of the respiratory system (stiff lung), was one of the mandatory criteria for ARDS diagnosis. In the mid-1980s, however, the first reports describing ARDS by using CT scanning changed the view of the syndrome [2][3][4]: the ARDS lung appeared to be affected by the disease process nonhomogeneously, with the CT densities distributed mainly in the dependent lung regions. The quantitative analysis of CT scanning gave new insights concerning the pathophysiology of the syndrome and provided a firm rationale for modifying the mechanical ventilation in use at that time [5][6][7]. This article discusses in some detail what the authors believe is or should be the role of the CT scanning in the diagnosis and therapy of ARDS. Quantitative analysis of CT scanningBecause the authors believe that the quantitative analysis of CT scanning is of paramount importance for ARDS diagnosis and for a rational setting of mechanical ventilation, a brief description of the technique and its limits is necessary. (A more detailed description of the quantitative analysis may be found elsewhere [7,8]). Physical principles of CT scanningThe digital image produced by the CT scan is based on the measure of the attenuation coefficient (m) (ie, the reduction of the radiation intensity upon passage through matter). Traversing from one side of the patient to the other, the X-ray beam is attenuated by all the voxels (volume elements of the tissue) through which passes. The intensity of the emerging X-ray is described by the Lambert law of absorption, that is,where I is the intensity of the emerging X-ray beam, and I 0 is the intensity of the X-ray beam at the source. By measuring the intensity I and I 0 , the CT calculates the integral over the function m of the attenuation coefficient along the X-ray beam. Then, through a different mathematical algorithm (usually filtered back projection), a given attenuation number m is assigned to each voxel (m voxel ). This attenuation number primarily represents the density of the voxel (ie, the ratio of mass to the volume) and is expressed as the CT number [9], which relates to the density of the water (m water ):CT ¼ 1000 Â m voxel À m water m waterConventionally a CT number equal to zero Hounsfield units (HU) indicates that density equals

show abstract

Body Position Changes Redistribute Lung Computed-Tomographic Density in Patients with Acute Respiratory Failure

Cited by 552 publications

References 0 publications

Clinical trial design—effect of prone positioning on clinical outcomes in infants and children with acute respiratory distress syndrome

Clinical trial design—effect of prone positioning on clinical outcomes in infants and children with acute respiratory distress syndrome

Does high PEEP prevent alveolar cycling?

The Role of CT-scan Studies for the Diagnosis and Therapy of Acute Respiratory Distress Syndrome

Contact Info

Product

Resources

About