Endotoxin effects on markers of autonomic nervous system function in the piglet: Implications for SIDS

• Published in: Biology of the neonate Vol. 86; no. 1; pp. 39 - 47
• Main Authors: VOSS, L. J, BOLTON, D. P. G, GALLAND, B. C, TAYLOR, B. J
• Format: Journal Article
• Language: English
• Published: Basel Karger 01.01.2004; S. Karger AG
• Subjects: Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Animals; Animals, Newborn; Autonomic Nervous System - drug effects; Autonomic Nervous System - physiopathology; Baroreflex - drug effects; Biological and medical sciences; Blood Pressure - drug effects; Body Temperature Regulation; Delivery. Postpartum. Lactation; Emergency and intensive care: neonates and children. Prematurity. Sudden death; Endotoxins - administration & dosage; Female; Gynecology. Andrology. Obstetrics; Heart Rate - drug effects; Humans; Infant, Newborn; Intensive care medicine; Male; Medical sciences; Nitroprusside - pharmacology; Phenylephrine - pharmacology; Salmonella; Sudden Infant Death - epidemiology; Sudden Infant Death - etiology; Swine; Neonatology; Baroreflex sensitivity; Infections; Marker; Endotoxin; Pig; Toxin; Vertebrata; Mammalia; Autonomic nervous system; Autonomic nervous system function; Animal; Sudden infant death syndrome; Artiodactyla; Heart rate variability; Ungulata
• ISSN: 0006-3126; 1661-7800; 1421-9727; 1661-7819
• DOI: 10.1159/000077452

The hypothesis was tested in 30 newborn piglets that the effects of a low dose of endotoxin (1 microg i.v. bolus; Salmonella abortus equi) would impair autonomic nervous system function. Two tests of autonomic function were performed following external warming (pre-endotoxin) and during endotoxin-generated thermogenesis: (1) analysis of heart rate variability in the time and frequency domains and (2) baroreflex sensitivity measured following intravenous injection of the vasoactive drugs nitroprusside and phenylephrine. Beat-to-beat heart rate variability (SDDeltaRR) fell by 2.2 ms from 7.0 ms before fever (p < 0.05). Low-frequency spectral power fell by 2.4 ms(2) from 4.1 ms(2) before fever (p < 0.05). The sensitivity of the baroreflex to changes in blood pressure induced by the vasoactive drugs decreased during fever by 0.72 ms/mm Hg for the nitroprusside test (p < 0.0005) and by 0.31 ms/mm Hg for the phenylephrine test (p < 0.005). These results indicate that in the piglet the balance of autonomic tone is altered and autonomic responsiveness reduced during the thermogenic phase of a fever. These findings are consistent with known risk factors for sudden infant death syndrome.