Abstract
Systemic blood flow (SBF) is maintained by an increased heart rate (HR) in S lambs at rest (SBF: 135±42 and 128±8 ml/min/kg in S and control lambs (C), resp.; HR 189±18 and 139±30 bpm; means±SD). Maximal HR is not likely to be different in S and C lambs. Consequently SBF will be lower in S lambs during exercise at maximal aerobic power (VO2max). VO2max itself will be lower too unless AV oxygen difference is increased. We studied 5 7-weeks-old lambs (12±1 kg) with a Goretex O graft between aorta (ao) and pulmonary artery (pa) (PBF: SBF ratio =3). Another 5 lambs of the same age and weight but without a graft served as controls. Variables were recorded at rest and at the point of exhaustion of a graded max. exercise test. HR was not significantly different during VO2max (S: 284±25 bpm; C:294±33). Consequently S lambs could not maintain SBF (285±27 ml/min/kg) at the level of C lambs (328±26; p<0.05). The limited ability to increase SBF was no stimulus for S lambs to increase their AV oxygen difference more than C lambs (S: 51±3 to 90±10; C: 48±3 to 95±8 mlO2/l). We conclude that S lambs cannot extract more oxygen to increase their VO2max.
Article PDF
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Gratama, J., Meuzelaar, J., Dalinghaus, M. et al. 125: MAXIMAL EXERCISE AND ARTERIOVENOUS OXYGEN DIFFERENCE IN LAMBS WITH AN AORTOPULMONARY SHUNT (S). Pediatr Res 24, 281 (1988). https://doi.org/10.1203/00006450-198808000-00150
Issue Date:
DOI: https://doi.org/10.1203/00006450-198808000-00150