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Biomedical subjects

S A Fagenholz

Publications and source records attributed to S A Fagenholz.

7 recordsLinked to original sources
PubMed1983

Cardiac dimensions in severely anemic neonatal pigs.

The effects of chronic severe anemia on weights and chamber volumes of hearts were studied in 9 spontaneously anemic neonatal pigs (mean hematocrit = 10.1%) and 10 healthy piglets (mean hematocrit = 28.3%) of approximately the same age and similar body weights. All cardiac chamber weights, as well as total heart weight/body weight ratios, were significantly higher in the anemic pigs than in the healthy pigs (P less than 0.001). The left ventricular free wall/right ventricular free wall weight ratio was identical in the 2 groups. Calculated left ventricular volume/body weight ratio also was significantly greater in the anemic pigs (P less than 0.05). It is concluded that cardiac dilatation and hypertrophy occur consistently in chronically anemic neonatal pigs. These changes are independent of age or body weight of the animal.

Anemia↗
PubMed1979

Laryngeal reflex apnea in the chemodenervated newborn piglet.

Effects of peripheral arterial chemodernervation on laryngeal reflex-induced apnea were studied in 18 piglets of either sex varying in age from 4 to 63 days. The distal trachea was cannulated with a cuffed endotracheal tube to secure a free airway and permit ventilatory measurements with a pneumotachograph. The proximal trachea was used to introduce fluids into the larynx. Water elicited apnea, bradycardia, and arterial hypertension, whereas saline caused only transient disturbances. Electrical stimulation of the superior laryngeal nerves reproduced, and conduction anesthesia ablated, the effects of water in the larynx. Carotid body contribution to respiratory drive was assessed by the ventilatory responses to increased (100%) and decreased (10%) anbient oxygen concentration. These indicated significant peripheral chemoreceptor ventilatory activity from birth with little further change in the neonatal period. Ventilatory responses to oxygen were ablated by carotid chemodenervation, but there was no change in the duration of laryngeal reflex apnea. We conclude that attenuation of laryngeal-induced apnea during postnatal development is independent of peripheral chemoreceptor activity. Our findings may have relevance to the clinical problem of sudden infant death syndrome, in which carotid body abnormalities have recently been described.

Animals↗
PubMed1977

Occult rupture of a main stem bronchus.

This report described a patient with multiple injuries in whom a major bronchial tear was not diagnosed early because the lung reexpanded initially. When pulmonary sepsis intervened and the bronchial injury was discovered, repair could not be accomplished because of continuing sepsis. The case emphasizes the need for early bronchoscopic evaluation in suspected bronchial injury even in the face of multiple other injuries which may draw the focus of attention away from a correctible bronchial disruption.

Adolescent↗
PubMed1976

Chemoreceptor function and sleep state in apnea.

Resting ventilation and ventilatory responses to 100% oxygen and to 5% carbon dioxide in air were measured in REM and non-REM sleep in post-neonatal infants. Normal controls were compared to infants with prolonged apnea and to siblings of sudden infant death victims. No significant differences in ventilatory responses were found between the groups. We conclude that apnea may occur in infants whose central and peripheral chemoreceptor activity is normal while they are breathing.

Apnea↗
PubMedDate not supplied

Association of anemia with reduced central respiratory drive in the piglet.

Central respiratory drive was studied in 13 piglets of both sexes varying in age from 19 to 67 days. The distal trachea was cannulated and the maximum rate of isometric inspiratory pressure change (dP/dt)(max), was measured at the airway. Curves were constructed relating this measurement to changes in arterial PCO(2) during carbon dioxide rebreathing. Data were obtained at intervals corresponding to stepwise reductions in central respiratory drive produced by added chloralose anaesthesia. Laryngeal reflex activation was achieved by electrical stimulation of the superior laryngeal nerves (SLN). This caused permanent respiratory arrest at a critical level of central respiratory depression expressed as the slope of the curve relating (dP/dt)(max) to arterial PCO(2). Severely anemic piglets showed markedly decreased central respiratory drive at a given dose of anesthesia compared to controls. This was consistent with the observed greater sensitivity to laryngeal nerve stimulation in these animals. It is concluded that anemia may be associated with impaired functional maturation of central respiratory mechanisms and consequent susceptibility to laryngeal reflex apnea and asphyxial death. These observations may pertain to factors associated with the sudden infant death syndrome.

Anemia↗