ABSTRACT
The effects of intravenous injections of the opiate antagonist naloxone (0.005-0.4 mg/kg body weight) on respiratory pattern, apnoea duration and frequency were investigated in six infants with severe sleep apnoea syndrome. Since several authors found elevated plasma- and CSF-levels of endogenous opioids (endorphines) in infants with sleep apnoea syndrome, we wanted to determine whether the impairment of the control mechanisms of respiration during sleep is due to an effect of endogenous opioids. Independent of the dose, naloxone did not exert any effect on respiratory pattern and occurrence of periodic apnoea. We were unable to prove that endorphines play a major role in pathogenesis of sleep apnoea syndrome in infancy and possibly in sudden infant death syndrome (SIDS). We speculate that elevated levels of endorphines reported by some investigators rather seem to be a consequence of hypoxic stress than a cause for sleep apnoeas.
Subject(s)
Naloxone/pharmacology , Respiration/drug effects , Sleep Apnea Syndromes/physiopathology , Sleep/drug effects , Sudden Infant Death/physiopathology , Aminophylline/therapeutic use , Drug Therapy, Combination , Female , Humans , Infant , Male , Naloxone/therapeutic use , Risk , Sleep/physiology , Sleep Apnea Syndromes/drug therapy , Sleep Apnea Syndromes/etiology , Sudden Infant Death/etiologySubject(s)
Deglutition , Respiration , Sleep Apnea Syndromes/physiopathology , Sucking Behavior/physiology , Humans , Infant , Time FactorsSubject(s)
Respiration , Sudden Infant Death/physiopathology , Apnea/physiopathology , Humans , Infant , Infant, Newborn , Retrospective Studies , Risk , Statistics as Topic , SyndromeABSTRACT
On the basis of two examples of projects being realized in the department of physiology in Graz the use of engineering methods in physiological research is demonstrated. The first example presents a survey of the use of system-theoretical methods for the investigation of overall regulation of circulation under working conditions. Using two test-signals (impulse input, random input) for experimental identification, the impulse response of heart-rate to changes in work load was obtained. The impulse responses of the volunteers were then characterized by a set of three parameters, allowing statistical evaluation, classification for diagnostic means and verification of hypotheses. The second example deals with an investigation of the signal structure of ultrasound-CW-Doppler-systems. Basing on the general Doppler-principle, which is already in use in angiology it was tried to quantify the determinants of the audio-signal, describing it by statistical functions and by experiments on simple models (tube-models). The goal of the experiments is a quantitative assessment of volume-flow and an enhancement of information about the scattering medium (rheological properties of blood).
