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Paediatric Pulmonology and Allergology
2003 April, Vol. VI, No. 1 (pp.2025-2033)
Different methods of breath reserve evaluation
Remigijus Voldemaras Nargela, Arturas Andziulis
Lung ventilation is an important oxygen transport system component. Lung ventilation has some reserves. Lung ventilation damage may cause oxygen transport system capacity limitation. It is important to evaluate lung ventilation reserves for pulmonary patients and persons with extreme exercise and oxygen transport system capacity needs.
There are several methods of lung ventilation capacity reserve estimation. Lung ventilation reserves may be measured at rest and exercise tolerance tests. The first kind of test is just models as MVV, the second kind of tests are directly measured of combined. Lung ventilation reserve may be estimated using lung volumes measure (maximal or partial) or the newest air flow measure methods during exercise tolerance tests.
Aim of the study was to compare both kind of methods.
There were observed 3 groups of patients, males, age 18-29: 42 athletes, 19 healthy persons and 12 patients with bronchial obstruction. All observations were performed with functional diagnostic system Vmax229. Tests equipment as spirometer (flow and volumes analyser) was the same during rest and exercise tests. Oxygen analyser was supplied by special SensorMedics fast paramagentic sensor, satisfied ATS requirements. Carbon dioxide analyser was supplied by special SensorMedic expanded quality infrared sensor, satisfied ATS requirements. Electronically braked bike ERGO900 occupied with control blood pressure meter was controlled by Vmax229 system. Controlled revolutions were 60-70rpm. There were performed standard 10min. ramp exercise test with maximal oxygen consumption for all patients or decreasing of cardio respiratory efficiency determined by HR/VO2 or VE/VO2 analysis by Jones and Wassermann for athletes and healthy persons or 4% desaturation for pulmonary patients. There were estimated lung ventilation changes during exercise with VD/VT, VT/VE and VE/VCO2 by J.Roca and all.
Patients with bronchial obstruction and athletes achieved the highest level of maximal ventilation (95% level confidence intervals are 108-130 L/min. and 90-104 L/min., but with different level of VO2MAX) than healthy persons (95% level confidence interval is 71-90 L/min., p<0.05). THere are no significant differences between breath reserves of athletes and healthy persons (43% and 49%) estimated by lung volumes measurement, but there are significant difference between both groups and obstructive patients (36%, p<0.05). There are significant differences between peak expiratory flow reserves of all three groups (46%, 39% and 21%, p<0.05). It's possible, that breath reserve estimated by lung volumes measurement is less sensitive than peak expiratory flow reserves estimation for patients with no obstruction or minimal lung ventilation disorder.