Diffusion capacity and CT measures of emphysema and airway wall thickness – relation to Arterial Oxygen Tension in COPD patients.

Background : Decreased diffusing capacity of the lung for carbon monoxide (DLCO) is associated with emphysema. DLCO is also related to decreased Arterial Oxygen Tension (PaO 2 ), but there are limited data on associations between PaO 2 and computed tomography (CT) derived measures of emphysema and airway wall thickness. Objective : To examine whether CT measures of emphysema and airway wall thickness are associated with level of Arterial Oxygen Tension beyond that provided by measurements of diffusion capacity and spirometry. Methods : The study sample consisted of 271 smoking or ex-smoking COPD patients from the Bergen COPD Cohort Study examined in 2007–2008. Emphysema was assessed as percent of low-attenuation areas

diffusion capacity and ct measures of emphysema and airway wall thickness relation to Arterial Oxygen Tension in copd patients

Background : Decreased diffusing capacity of the lung for carbon monoxide (DLCO) is associated with emphysema. DLCO is also related to decreased Arterial Oxygen Tension (PaO 2 ), but there are limited data on associations between PaO 2 and computed tomography (CT) derived measures of emphysema and airway wall thickness. Objective : To examine whether CT measures of emphysema and airway wall thickness are associated with level of Arterial Oxygen Tension beyond that provided by measurements of diffusion capacity and spirometry. Methods : The study sample consisted of 271 smoking or ex-smoking COPD patients from the Bergen COPD Cohort Study examined in 2007–2008. Emphysema was assessed as percent of low-attenuation areas<−950 Hounsfield units (%LAA), and airway wall thickness as standardised measure at an internal perimeter of 10 mm (AWT-Pi10). Multiple linear regression models were fitted with PaO 2 as the outcome variable, and %LAA, AWT-Pi10, DLCO and carbon monoxide transfer coefficient (KCO) as main explanatory variables. The models were adjusted for sex, age, smoking status, and haemoglobin concentration, as well as forced expiratory volume in one second (FEV 1 ). Results : Sixty two per cent of the subjects were men, mean (SD) age was 64 (7) years, mean (SD) FEV 1 in percent predicted was 50 (15)%, and mean PaO 2 (SD) was 9.3 (1.1) kPa. The adjusted regression coefficient (CI) for PaO 2 was –0.32 (−0.04–(−0.019)) per 10% increase in %LAA ( p <0.01). When diffusion capacity and FEV 1 were added to the model, respectively, the association lost its statistical significance. No relationship between airway wall thickness and PaO 2 was found. Conclusion : CT assessment of airway wall thickness is not associated with Arterial Oxygen Tension in COPD patients. Emphysema score measured by chest CT, is related to decreased PaO 2 , but cannot replace measurements of diffusion capacity in the clinical evaluation of hypoxaemia. Keywords: Arterial Oxygen Tension; diffusion capacity; emphysema; airway wall thickness; computed tomography; COPD (Published: 12 May 2016) Citation: European Clinical Respiratory Journal 2016, 3: 29141 – http://dx.doi.org/10.3402/ecrj.v3.29141

Diffusion capacity and CT measures of emphysema and airway wall thickness – Relation to Arterial Oxygen Tension in COPD patients

Background: There is limited data on the relationship between Arterial Oxygen Tension (PaO2) and computed tomography (CT) derived data on emphysema and airway wall thickness.

Objective: To examine the predictive value of measures of emphysema and airway wall thickness from CT scans on PaO2.

Methods: The study sample consisted of 271 smoking or ex-smoking COPD patients from the Bergen COPD Cohort Study examined in 2007-2008. Emphysema was assessed as percent of low-attenuation areas < -950 Hounsfield units (%LAA), and airway wall thickness as standardized measures at an internal perimeter of 10mm (Pi10). Multiple linear regression models were fitted with PaO2 as the outcome variable, and %LAA, Pi10, DLCO and/or KCO as predictor variables. Also, adjustments for gender, age, smoking status (current/ex), and haemoglobin (in analyses with DLCO and KCO) were made. Results: 62% of the subjects were men, mean(SD) age was 64(7) years, mean(SD) FEV1 in percent predicted was 50(15)%, and mean PaO2(SD) was 9.3(1.1) kPa. The adjusted regression coefficient (SE) for PaO2 was - 0.32 (0.06) per 10% increase in %LAA (p

Diffusion capacity and CT measures of emphysema and airway wall thickness – relation to Arterial Oxygen Tension in COPD patients.

Background : Decreased diffusing capacity of the lung for carbon monoxide (DLCO) is associated with emphysema. DLCO is also related to decreased Arterial Oxygen Tension (PaO 2 ), but there are limited data on associations between PaO 2 and computed tomography (CT) derived measures of emphysema and airway wall thickness. Objective : To examine whether CT measures of emphysema and airway wall thickness are associated with level of Arterial Oxygen Tension beyond that provided by measurements of diffusion capacity and spirometry. Methods : The study sample consisted of 271 smoking or ex-smoking COPD patients from the Bergen COPD Cohort Study examined in 2007–2008. Emphysema was assessed as percent of low-attenuation areas

diffusion capacity and ct measures of emphysema and airway wall thickness relation to Arterial Oxygen Tension in copd patients

Background : Decreased diffusing capacity of the lung for carbon monoxide (DLCO) is associated with emphysema. DLCO is also related to decreased Arterial Oxygen Tension (PaO 2 ), but there are limited data on associations between PaO 2 and computed tomography (CT) derived measures of emphysema and airway wall thickness. Objective : To examine whether CT measures of emphysema and airway wall thickness are associated with level of Arterial Oxygen Tension beyond that provided by measurements of diffusion capacity and spirometry. Methods : The study sample consisted of 271 smoking or ex-smoking COPD patients from the Bergen COPD Cohort Study examined in 2007–2008. Emphysema was assessed as percent of low-attenuation areas<−950 Hounsfield units (%LAA), and airway wall thickness as standardised measure at an internal perimeter of 10 mm (AWT-Pi10). Multiple linear regression models were fitted with PaO 2 as the outcome variable, and %LAA, AWT-Pi10, DLCO and carbon monoxide transfer coefficient (KCO) as main explanatory variables. The models were adjusted for sex, age, smoking status, and haemoglobin concentration, as well as forced expiratory volume in one second (FEV 1 ). Results : Sixty two per cent of the subjects were men, mean (SD) age was 64 (7) years, mean (SD) FEV 1 in percent predicted was 50 (15)%, and mean PaO 2 (SD) was 9.3 (1.1) kPa. The adjusted regression coefficient (CI) for PaO 2 was –0.32 (−0.04–(−0.019)) per 10% increase in %LAA ( p <0.01). When diffusion capacity and FEV 1 were added to the model, respectively, the association lost its statistical significance. No relationship between airway wall thickness and PaO 2 was found. Conclusion : CT assessment of airway wall thickness is not associated with Arterial Oxygen Tension in COPD patients. Emphysema score measured by chest CT, is related to decreased PaO 2 , but cannot replace measurements of diffusion capacity in the clinical evaluation of hypoxaemia. Keywords: Arterial Oxygen Tension; diffusion capacity; emphysema; airway wall thickness; computed tomography; COPD (Published: 12 May 2016) Citation: European Clinical Respiratory Journal 2016, 3: 29141 – http://dx.doi.org/10.3402/ecrj.v3.29141

Diffusion capacity and CT measures of emphysema and airway wall thickness – Relation to Arterial Oxygen Tension in COPD patients

Background: There is limited data on the relationship between Arterial Oxygen Tension (PaO2) and computed tomography (CT) derived data on emphysema and airway wall thickness.

Objective: To examine the predictive value of measures of emphysema and airway wall thickness from CT scans on PaO2.

Methods: The study sample consisted of 271 smoking or ex-smoking COPD patients from the Bergen COPD Cohort Study examined in 2007-2008. Emphysema was assessed as percent of low-attenuation areas < -950 Hounsfield units (%LAA), and airway wall thickness as standardized measures at an internal perimeter of 10mm (Pi10). Multiple linear regression models were fitted with PaO2 as the outcome variable, and %LAA, Pi10, DLCO and/or KCO as predictor variables. Also, adjustments for gender, age, smoking status (current/ex), and haemoglobin (in analyses with DLCO and KCO) were made. Results: 62% of the subjects were men, mean(SD) age was 64(7) years, mean(SD) FEV1 in percent predicted was 50(15)%, and mean PaO2(SD) was 9.3(1.1) kPa. The adjusted regression coefficient (SE) for PaO2 was - 0.32 (0.06) per 10% increase in %LAA (p

Changes in Arterial Oxygen Tension when weaning neonates from inhaled nitric oxide

We set out to evaluate changes in Arterial Oxygen Tension (PaO 2 ) when weaning neonates from inhaled nitric oxide (INO). We reviewed the records of 505 prospectively collected INO weaning attempts on 84 neonates with hypoxic respiratory failure. PaO 2 values before and 30 min after weaning attempts were recorded. Relationships between change in PaO 2 and decreases in INO concentrations were investigated using regression analysis and ANOVA. PaO 2 decreased (- 18.7 ± 1.8 torr; P < 0.001) when weaning INO. A stepwise decline in PaO 2 was observed weaning INO from 40 ppm. The greatest decline occurred when INO was discontinued (-42.1 ± 4.1 torr). Forward stepwise multiple regression using variables with significant relationships to the decline in PaO 2 identified the specific dose reduction (P

Changes in Arterial Oxygen Tension when weaning neonates from inhaled nitric oxide

We set out to evaluate changes in Arterial Oxygen Tension (PaO2) when weaning neonates from inhaled nitric oxide (INO). We reviewed the records of 505 prospectively collected INO weaning attempts on 84 neonates with hypoxic respiratory failure. PaO2 values before and 30 min after weaning attempts were recorded. Relationships between change in PaO2 and decreases in INO concentrations were investigated using regression analysis and ANOVA.

PaO2 decreased (−18.7 ± 1.8 torr; P 

changes in Arterial Oxygen Tension when weaning neonates from inhaled nitric oxide

We set out to evaluate changes in Arterial Oxygen Tension (PaO2) when weaning neonates from inhaled nitric oxide (INO). We reviewed the records of 505 prospectively collected INO weaning attempts on 84 neonates with hypoxic respiratory failure. PaO2 values before and 30 min after weaning attempts were recorded. Relationships between change in PaO2 and decreases in INO concentrations were investigated using regression analysis and ANOVA.

PaO2 decreased (−18.7 ± 1.8 torr; P < 0.001); when weaning INO. A stepwise decline in PaO2 was observed weaning INO from 40 ppm. The greatest decline occurred when INO was discontinued (−42.1 ± 4.1 torr). Forward stepwise multiple regression using variables with significant relationships to the decline in PaO2 identified the specific dose reduction 7(P < 0.001), the prewean PaO2 (P < 0.001), and surfactant therapy (P = 0.018) as the variables best describing the change in PaO2(P = 0.004, r = 0.51). In conclusion, a graded decline in PaO2 occurs when reducing INO. INO should be weaned to less than 1 ppm before discontinuing its use. Prior surfactant treatment appears to enhance the Oxygenation reserve when weaning INO. Pediatr Pulmonol. 2001; 32:14–19. © 2001 Wiley-Liss,Inc.