No compensatory lung growth after resection in a one-year follow-up cohort of patients with lung cancer.

BACKGROUND: As compensatory lung growth after lung resection has been studied in animals of various ages and in one case report in a young adult, it has not been studied in a cohort of adults operated for lung cancer. METHODS: A prospective study including patients with lung cancer was conducted over two years. Parenchymal mass was calculated using computed tomography before (M0) and at 3 and 12 months (M3 and M12) after surgery. Respiratory function was estimated by plethysmography and CO/NO lung transfer (DLCO and DLNO). Pulmonary capillary blood volume (Vc) and membrane conductance for CO (DmCO) were calculated. Insulin-like growth factor-1 (IGF-1) and insulin-like growth factor binding protein-3 (IGFBP-3) plasma concentrations were measured simultaneously. RESULTS: Forty-nine patients underwent a pneumonectomy (N=12) or a lobectomy (N=37) thirty two completed the protocol. Among all patients, from M3 to M12 the masses of the operated lungs (239±58 to 238±72 g in the lobectomy group) and of the non-operated lungs (393±84 to 377±68 g) did not change. Adjusted by the alveolar volume (VA), DLNO/VA decreased transiently by 7% at M3, returning towards the M0 value at M12. Both Vc and DmCO increased slightly between M3 and M12. IGF-1 and IGFBP-3 concentrations did not change at M3, IGF-1 decreased significantly from M3 to M12. CONCLUSIONS: Compensatory lung growth did not occur over one year after lung surgery. The lung function data could suggest a slight recruitment or distension of capillaries owing to the likely hemodynamic alterations. An angiogenesis process is unlikely.

Feasibility of intercostal blood flow measurement by echo-Doppler technique in healthy subjects.

Intercostal artery blood flow supplies the external and internal intercostal muscles, which are inspiratory and expiratory muscles. Intercostal blood flow measured by the echo-Doppler (ED) technique has not previously been reported in humans. This study describes the feasibility of this measurement during free and loaded breathing in healthy subjects. Systolic, diastolic and mean blood flows were measured in the eighth dorsal intercostal space during free and loaded breathing using the ED technique. Flows were calculated as the product of the artery intraluminal surface and blood velocity. Ten healthy subjects (42 ± 13·6 years) were included. Integrated electromyogram (iEMG), arterial pressure, cardiac frequency and breathing pattern were also recorded. Mean blood flows were 3·5 ± 1·2 ml min-1 at rest, 6 ± 2·6 ml min-1 while breathing through a combined inspiratory and expiratory resistance and 4·0 ± 1·3 ml min-1 1 min after unloading. Diastolic blood flow was about one-third the systolic blood flow. The changes in blood flows were consistent with those in iEMG. No change in mean blood flow was observed between inspiration and expiration, suggesting a balance in the perfusion of external and internal muscles during breathing. In conclusion, ED is a feasible technique for non-invasive, real-time measurement of intercostal blood flow in humans. In healthy subjects, mean blood flow appeared tightly matched to iEMG activity. This technique may provide a way to assess the vascular adaptations induced by diseases in which respiratory work is increased or cardiac blood flow altered.

Deciphering the nitric oxide to carbon monoxide lung transfer ratio: physiological implications.

Using simultaneous nitric oxide and carbon monoxide lung transfer measurements (T(LNO) and T(LCO)), the membrane transfer capacity (D(m)) and capillary lung volume (V(c)) as well as the dimensionless ratio T(LNO)/T(LCO) can be calculated. The significance of this ratio is yet unclear. Theoretically, the T(LNO)/T(LCO) ratio should be inversely related to the product of both lung alveolar capillary membrane (mu) and blood sheet thicknesses (K). NO and CO transfers were measured in healthy subjects in various conditions likely to be associated with changes in K and/or mu. Experimentally, deflation of the lung from 7.4 to 4.8 l decreased the T(LNO)/T(LCO) ratio from 4.9 to 4.2 (n=25) which was consistent mainly with a thickening of the blood sheet. Compared with continuous negative pressure breathing, continuous positive pressure breathing increased this ratio suggesting a thinning of the capillary sheet. It was also observed with 12 healthy subjects that slight haemodilution that may thicken the blood sheet decreased the T(LNO)/T(LCO) ratio from 4.85 to 4.52. In conclusion, the T(LNO)/T(LCO) ratio is related to the thickness of the alveolar blood barrier. This ratio provides novel information for the analysis of the diffusion properties.

Membrane conductance in trained and untrained subjects using either steady state or single breath measurements of NO transfer.

The aim of this work was to define the relationship between membrane conductance for NO (Dm) and physical activity by using either the steady state NO transfer (T(LNO)SS) or the single breath method (T(LNO)SB), making the hypothesis that NO transfer is only limited by the membrane. Alterations in T(LNO)SS with lung volume during tidal ventilation were measured in six subjects at rest and during steady exercise at 30, 60, and 80% of maximal aerobic power (MAP). A fast responding chemoluminescent NO analyser was used. Two calculation methods were used by sampling NO: (1) at mid-tidal volume, (2) in the middle of the alveolar plateau. T(LNO)SB at rest and maximal oxygen consumption (V(.-)O(2)max) were also measured in 18 other subjects. At rest T(LNO)SS with method 2 was 192% of the value given by method 1. T(LNO)SS with method 1 increased by 50% with 80% MAP as it did not change with method 2. Method 2 seemed inaccurate. T(LNO)SB at rest, which is closely related to Dm, was correlated to age and V(.-)O(2)max, T(LNO)SB=182-1.2 age+24.3 V(.-)O(2) max(l min(-1)) (p<0.01, r(2)=0.72). The T(LNO)SS and T(LNO)SB versus lung volume relationships suggest an influence of the breathing pattern on Dm. Dm can be estimated either by these two NO transfer methods, however the use of the T(LNO)SS method is highly sensitive to the alveolar sampling level. Dm increase during exercise is a function of MAP. Dm at rest decreases with age as it increases with MAP.

Effects of a Basketball Activity on Lung Capillary Blood Volume and Membrane Diffusing Capacity, Measured by NO/CO Transfer in Children.

In both children and adults, acute exercise increases lung capillary blood volume (Vc) and membrane factor (DmCO). We sought to determine whether basketball training affected this adaptation to exercise in children. The purpose of this study was to determine the effects of two years sport activity on the components of pulmonary gas transfer in children. Over a 2-yr period, we retested 60 nine year old boys who were initially separated in two groups: 30 basketball players (P) (9.0 ± 1.0 yrs; 35.0 ± 5.2 kg; 1.43 ± 0.05 m), and matched non players controls (C) (8.9 ± 1.0 yrs; 35.0 ± 6.0 kg; 1.44 ± 0.06 m) who did not perform any extracurricular activity, Vc and DmCO were measured by the NO/CO transfer method at rest and during sub-maximal exercise. Maximal aerobic power and peak power output was 12% higher in the trained group compared to matched controls (p < 0.05). Nitric oxide lung transfer (TLNO) per unit lung volume and thus, DmCO per unit of lung volume (VA) were higher at rest and during exercise in the group which had undergone regular basketball activity compared to matched controls (p < 0.05). Neither lung capillary blood volume nor total lung transfer for carbon monoxide (TLCO) were significantly different between groups. These results suggest that active sport can alter the properties of the lung alveolo-capillary membrane by improving alveolar membrane conductance in children. Key PointsTrained children had greater DmCO/VA and DmCO/Vc ratios compared with control children during exercise.The mechanisms by which basketball playing children were thought to improve lung diffusion are speculative.Further work will be required to determine the kinetics of the alteration in Dm when children switch from non players to players status or vice-versa.