Author:
Schulz Steffen,Reulecke Sina,Eiselt Michael,Schwab Karin,Witte Herbert,Walter Bernd,Bauer Reinhard,Voss Andreas
Abstract
Abstract
Background
Newborn mammals suffering from moderate hypoxia during or after birth are able to compensate a transitory lack of oxygen by adapting their vital functions. Exposure to hypoxia leads to an increase in the sympathetic tone causing cardio-respiratory response, peripheral vasoconstriction and vasodilatation in privileged organs like the heart and brain. However, there is only limited information available about the time and intensity changes of the underlying complex processes controlled by the autonomic nervous system.
Methods
In this study an animal model involving seven piglets was used to examine an induced state of circulatory redistribution caused by moderate oxygen deficit. In addition to the main focus on the complex dynamics occurring during sustained normocapnic hypoxia, the development of autonomic regulation after induced reoxygenation had been analysed. For this purpose, we first introduced a new algorithm to prove stationary conditions in short-term time series. Then we investigated a multitude of indices from heart rate and blood pressure variability and from bivariate interactions, also analysing respiration signals, to quantify the complexity of vegetative oscillations influenced by hypoxia.
Results
The results demonstrated that normocapnic hypoxia causes an initial increase in cardiovascular complexity and variability, which decreases during moderate hypoxia lasting one hour (p < 0.004). After reoxygenation, cardiovascular complexity parameters returned to pre-hypoxic values (p < 0.003), however not respiratory-related complexity parameters.
Conclusions
In conclusion, indices from linear and nonlinear dynamics reflect considerable temporal changes of complexity in autonomous cardio-respiratory regulation due to normocapnic hypoxia shortly after birth. These findings might be suitable for non-invasive clinical monitoring of hypoxia-induced changes of autonomic regulation in newborn humans.
Publisher
Springer Science and Business Media LLC
Subject
Radiology Nuclear Medicine and imaging,Biomedical Engineering,General Medicine,Biomaterials,Radiological and Ultrasound Technology
Reference40 articles.
1. Sinha SK, Donn SM: Fetal-to-neonatal maladaptation. Semin Fetal Neonatal Med 2006, 11: 166–173. 10.1016/j.siny.2006.01.008
2. Bauer R: Stupor and coma: pathophysiology of hypoxia--ontogenetic aspects. Suppl Clin Neurophysiol 2004, 57: 681–687.
3. Gootman PM, Gootman N: Postnatal changes in cardiovascular regulation during hypoxia. Adv Exp Med Biol 2000, 475: 539–548.
4. Gootman PM, Gootman N, Buckley BJ: Maturation of central autonomic control of the circulation. Fed Proc 1983, 42: 1648–1655.
5. Zwiener U, Hoyer D, Bauer R, Luthke B, Walter B, Schmidt K, Hallmeyer S, Kratzsch B, Eiselt M: Deterministic--chaotic and periodic properties of heart rate and arterial pressure fluctuations and their mediation in piglets. Cardiovasc Res 1996, 31: 455–465.
Cited by
8 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献