Dataset Information

Early quantitative CT analysis of oleic acid induced acute respiratory distress syndrome in a canine model.

ABSTRACT:

Background

Although quantitative computed tomography (CT) has been used to analyze the lungs of patients with confirmed diagnoses of acute respiratory distress syndrome (ARDS), there are few reports to show the diagnosis during the early stage of ARDS. Using a canine model and quantitative CT, we aimed to develop an oleic acid (OA) induced ARDS regarding the early stage of ARDS that could improve in the early diagnosis of ARDS.

Methods

Fourteen healthy beagle dogs underwent CT. Their lung tissue was manually partitioned into four compartments, i.e., non-aerated, poorly aerated, normally aerated, and hyper-aerated lung compartments. The mean CT attenuation value Hounsfield unit (HU), tissue mass (g), residual volume (ml), and percentage of lung area were automatically determined for each lung compartment and compared between groups by receiver operating characteristic curve (ROC) analyses using area under curve (AUC). The optimized cut-off point for each parameter was determined by Youden's index.

Results

Regarding lung compartments during the expiratory phase, the percentage of non-aerated lung area in the ARDS group was higher vs. controls at all time points (T1 to T6). CT attenuation values for the ARDS group increased with time during both respiratory phases compared with controls. During both respiratory phases, tissue mass within the ARDS group significantly increased compared with controls at T3-T6.

Conclusions

Quantitative CT analysis can detect ARDS at an early stage with high sensitivity and specificity, providing a minimum of assistance in the early diagnosis of ARDS.

SUBMITTER: Chen H

PROVIDER: S-EPMC4509184 | biostudies-literature | 2015

REPOSITORIES: biostudies-literature

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Publications

Early quantitative CT analysis of oleic acid induced acute respiratory distress syndrome in a canine model.

Chen Huai H Zeng Qing-Si QS Chen Rong-Chang RC Li Wen W Zhou Jia-Xuan JX Liu Qin Q Dai Wang-Chun WC

International journal of clinical and experimental medicine 20150515 5

<h4>Background</h4>Although quantitative computed tomography (CT) has been used to analyze the lungs of patients with confirmed diagnoses of acute respiratory distress syndrome (ARDS), there are few reports to show the diagnosis during the early stage of ARDS. Using a canine model and quantitative CT, we aimed to develop an oleic acid (OA) induced ARDS regarding the early stage of ARDS that could improve in the early diagnosis of ARDS.<h4>Methods</h4>Fourteen healthy beagle dogs underwent CT. Th ...[more]

PMID: 26221239

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Project description:IntroductionThe clinical use of serial quantitative computed tomography (CT) to characterize lung disease and guide the optimization of mechanical ventilation in patients with acute respiratory distress syndrome (ARDS) is limited by the risk of cumulative radiation exposure and by the difficulties and risks related to transferring patients to the CT room. We evaluated the effects of tube current-time product (mAs) variations on quantitative results in healthy lungs and in experimental ARDS in order to support the use of low-dose CT for quantitative analysis.MethodsIn 14 sheep chest CT was performed at baseline and after the induction of ARDS via intravenous oleic acid injection. For each CT session, two consecutive scans were obtained applying two different mAs: 60 mAs was paired with 140, 15 or 7.5 mAs. All other CT parameters were kept unaltered (tube voltage 120 kVp, collimation 32 × 0.5 mm, pitch 0.85, matrix 512 × 512, pixel size 0.625 × 0.625 mm). Quantitative results obtained at different mAs were compared via Bland-Altman analysis.ResultsGood agreement was observed between 60 mAs and 140 mAs and between 60 mAs and 15 mAs (all biases less than 1%). A further reduction of mAs to 7.5 mAs caused an increase in the bias of poorly aerated and nonaerated tissue (-2.9% and 2.4%, respectively) and determined a significant widening of the limits of agreement for the same compartments (-10.5% to 4.8% for poorly aerated tissue and -5.9% to 10.8% for nonaerated tissue). Estimated mean effective dose at 140, 60, 15 and 7.5 mAs corresponded to 17.8, 7.4, 2.0 and 0.9 mSv, respectively. Image noise of scans performed at 140, 60, 15 and 7.5 mAs corresponded to 10, 16, 38 and 74 Hounsfield units, respectively.ConclusionsA reduction of effective dose up to 70% has been achieved with minimal effects on lung quantitative results. Low-dose computed tomography provides accurate quantitative results and could be used to characterize lung compartment distribution and possibly monitor time-course of ARDS with a lower risk of exposure to ionizing radiation. A further radiation dose reduction is associated with lower accuracy in quantitative results.

Project description:BackgroundA continuous gas flow provided by flow-controlled ventilation (FCV) facilitates accurate dynamic compliance measurement and allows the clinician to individually optimise positive end-expiratory and peak pressure settings accordingly.ObjectiveThe aim of this study was to compare the efficiency of gas exchange and impact on haemodynamics between individualised FCV and pressure-controlled ventilation (PCV) in a porcine model of oleic acid-induced acute respiratory distress syndrome (ARDS).DesignRandomised controlled interventional trial conducted on 16 pigs.SettingAnimal operating facility at the Medical University Innsbruck.InterventionsARDS was induced in lung healthy pigs by intravenous infusion of oleic acid until moderate-to-severe ARDS at a stable Horowitz quotient (PaO 2 FiO 2-1 ) of 80 to 120 over a period of 30 min was obtained. Ventilation was then either performed with individualised FCV ( n = 8) established by compliance-guided pressure titration or PCV ( n = 8) with compliance-guided titration of the positive end-expiratory pressure and peak pressure set to achieve a tidal volume of 6 ml kg -1 over a period of 2 h.Main outcome measuresGas exchange parameters were assessed by the PaO 2 FiO 2-1 quotient and CO 2 removal by the PaCO 2 value in relation to required respiratory minute volume. Required catecholamine support for haemodynamic stabilisation was measured.ResultsThe FCV group showed significantly improved oxygenation [149.2 vs. 110.4, median difference (MD) 38.7 (8.0 to 69.5) PaO 2 FiO 2-1 ; P = 0.027] and CO 2 removal [PaCO 2 7.25 vs. 9.05, MD -1.8 (-2.87 to -0.72) kPa; P = 0.006] at a significantly lower respiratory minute volume [8.4 vs. 11.9, MD -3.6 (-5.6 to -1.5) l min -1 ; P = 0.005] compared with PCV. In addition, in FCV-pigs, haemodynamic stabilisation occurred with a significant reduction of required catecholamine support [norepinephrine 0.26 vs. 0.86, MD -0.61 (-1.12 to -0.09) μg kg -1 min -1 ; P = 0.037] during 2 ventilation hours.ConclusionIn this oleic acid-induced porcine ARDS model, individualised FCV significantly improved gas exchange and haemodynamic stability compared with PCV.Trial registrationProtocol no.: BMBWF-66.011/0105-V/3b/2019).

Project description:BACKGROUND:The benefits of early continuous neuromuscular blockade in patients with acute respiratory distress syndrome (ARDS) who are receiving mechanical ventilation remain unclear. METHODS:We randomly assigned patients with moderate-to-severe ARDS (defined by a ratio of the partial pressure of arterial oxygen to the fraction of inspired oxygen of <150 mm Hg with a positive end-expiratory pressure [PEEP] of ?8 cm of water) to a 48-hour continuous infusion of cisatracurium with concomitant deep sedation (intervention group) or to a usual-care approach without routine neuromuscular blockade and with lighter sedation targets (control group). The same mechanical-ventilation strategies were used in both groups, including a strategy involving a high PEEP. The primary end point was in-hospital death from any cause at 90 days. RESULTS:The trial was stopped at the second interim analysis for futility. We enrolled 1006 patients early after the onset of moderate-to-severe ARDS (median, 7.6 hours after onset). During the first 48 hours after randomization, 488 of the 501 patients (97.4%) in the intervention group started a continuous infusion of cisatracurium (median duration of infusion, 47.8 hours; median dose, 1807 mg), and 86 of the 505 patients (17.0%) in the control group received a neuromuscular blocking agent (median dose, 38 mg). At 90 days, 213 patients (42.5%) in the intervention group and 216 (42.8%) in the control group had died before hospital discharge (between-group difference, -0.3 percentage points; 95% confidence interval, -6.4 to 5.9; P?=?0.93). While in the hospital, patients in the intervention group were less physically active and had more adverse cardiovascular events than patients in the control group. There were no consistent between-group differences in end points assessed at 3, 6, and 12 months. CONCLUSIONS:Among patients with moderate-to-severe ARDS who were treated with a strategy involving a high PEEP, there was no significant difference in mortality at 90 days between patients who received an early and continuous cisatracurium infusion and those who were treated with a usual-care approach with lighter sedation targets. (Funded by the National Heart, Lung, and Blood Institute; ROSE ClinicalTrials.gov number, NCT02509078.).

Dataset Information

Early quantitative CT analysis of oleic acid induced acute respiratory distress syndrome in a canine model.

Background

Methods

Results

Conclusions

Publications

Early quantitative CT analysis of oleic acid induced acute respiratory distress syndrome in a canine model.

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