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Biomedical subjects

M Samanek

Publications and source records attributed to M Samanek.

17 recordsLinked to original sources
PubMed1993

Lung function in children and adolescents with tetralogy of Fallot after intracardiac repair.

We studied lung function in 41 patients, aged 6-27 years, 1-5 years after intracardiac surgical repair (ICR) of tetralogy of Fallot (TOF) and about 5 years after the establishment of the Pediatric Cardiac Center in Prague. The measurements included vital capacity (VC), total lung capacity (TLC), functional residual capacity (FRC), residual volume (RV), forced expiratory flows (FEF), specific airway conductance (SGaw), lung recoil pressure (Pst), and specific static lung compliance (SC1st). Single or multiple abnormal lung function parameters were found in 83% of patients. Lung function was not related to shunting operations prior to ICR, hemoglobin concentration, and hematocrit, and had no specific pattern. Pst at 100% TLC and 90% TLC declined with increasing age at ICR and at lung function testing, while SC1st rose, as did the ratio FRC/TLC. Fifteen patients were studied before and after surgery. Single or multiple lung function tests were abnormal in 93% before and in 84% after ICR. After ICR the ratios FRC/TLC and also RV/TLC, FEF at 25% VC, and FEF at 60% TLC were less frequently abnormal, while Pst at 100% TLC and at 90% TLC, as well as SGaw and TLC, were more frequently abnormal after ICR. The results indicated a regression of smaller airway obstruction and lung hyperinflation after ICR. The evolution of abnormally compliant (emphysematous) lungs with growth of the patients might be a sign of permanent sequelae of early lung damage from abnormal pulmonary hemodynamics.

Adolescent↗
PubMed1976

Pulmonary elasticity in children and adolescents.

Static (Cst(L)), dynamic (Cdyn(L)), and "specific lung compliance (CL/TLC, CL/FRC) and the elastic recoil pressure of the lungs (Pst/(L)) were measured in 131 healthy children and the adolescents (age 6 to 17 years) from simultaneous recordings of esophageal pressure and lung volume. Esophageal elastance and vertical esophageal pressure gradients were also studied. Pst(L), measured at different lung volumes (fractional) from the expiratory quasi-static pressure-volume (PV) curves of the lungs, increased significantly with increasing body height, age, and body surface. Cst(L), determined from the midportion of PV curves, and Cdyn(L) measured during normal breathing at frequencies around 20/min also increased significantly with somatic growth. "Specific" Cst(L) decreased with increasing body height, age, and body surface. "Specific" Cdyn(L), esophageal elastance, and the vertical esophageal pressure gradient were independent of body height, age, and body surface, Cdyn(L) was less than Cst(L) mainly in smaller and younger children, and was not considered a valid index of pulmonary elasticity. Values of Pst(L), "specific" Cst(L), and the change of slope of the midportion of PV curves in children and adolescents suggested developmental changes of pulmonary elasticity in man over the age range studied.

Adolescent↗
PubMedDate not supplied

Lung function abnormalities in cystic fibrosis and changes during growth.

Static lung volumes (VC, TLC, FRC, RV), elastic recoil pressure of the lungs (Pst(1) at 100, 90, and 60% of TLC), static lung compliance [Cst(1)], specific airway conductance at FRC level (Gaw/TGVex), forced expiratory volume in the first second (FEV1), maximal expiratory flows (Vmax.) at 25 and 50% of VC and at 60% of TLC, and "upstream" airway conductance (Gus) at 60% of TLC were studied in 28 patients with cystic fibrosis, 5 to 25 years old, over a period of 1 to 5 years. The data were compared individually with normal values, related to body height in the form of regression equations and expressed in percentage of predicted values. From the indices assessing airway function, Vmax. at low lung volumes, Gus at 60% TLC, RV and RV/TLC were the functional parameters most consistently abnormal. Among the indices characterizing lung elasticity, Pst(1) at 60% TLC was the most abnormal. Generally, the values of the majority of lung function indices [VC, TLC, FRC, Pst(1)] declined during growth. Vmax. at all lung volumes and Gus at 60% TLC did not deteriorate with growth probably due to the great abnormality of these parameters already in young patients. It was also observed that lung function did not change significantly over a period of 1 to 5 years corresponding to a 10 cm increase in body height. However, over that period, lung function improved in some of the subjects, did not change in over 50% of the cases and deteriorated in the others.

Adolescent↗
PubMedDate not supplied

Upstream and total airway conductance in children and adolescents.

Static lung volumes, pressure-volume curves, airway conductance (Gaw) and maximum expiratory flow-volume curves were obtained in a group of healthy children and adolescents (age 6 to 17 years, body height 115 to 180 cm). Relating lung recoil pressure to maximum expiratory flow at the same lung volume level allowed the calculation of the conductance of the upstream segment (Gus). Gaw increased with increased body height and lung volume, so that specific Gaw did not change during growth. Gus also increased with body height, except at lower lung volume, but when corrected for simultaneous changes in lung volume it decreased. These physiological results suggest that the central airways grow proportionately to the changes in lung volume, whereas the growth of the peripheral airways is proportionately less marked. It is however not possible to draw definite conclusions on the isotropical or anisotropical growth of different parts of the lungs from these physiological observations.

Adolescent↗