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Biomedical subjects

N Gootman

Publications and source records attributed to N Gootman.

At least 55 records · Page 3Linked to original sources
PubMed1981

Autonomic regulation of cardiovascular function in neonates.

The degree of participation of the vascular bed supplied by the superior mesenteric artery in autonomic regulation of cardiovascular function during postnatal maturation was evaluated in piglets, ranging in age from birth to two months. Animals were anaesthetized with 0.25-0.5% halothane in a 50% mixture of N2O and O2, paralysed with decamethonium bromide and artificially ventilated to maintain normal arterial blood gases and pH. Mesenteric arterial flow was recorded continuously with an electromagnetic flow transducer; simultaneously aortic pressure, heart rate, and femoral, renal and carotid flows were monitored. Resistance was calculated as the ratio of mean aortic pressure to mean flow. The central neural regulation of the cardiovascular system was altered: (1) by electrical stimulation of medullary vasoactive sites, (2) by changing the input from visceral or somatic afferents and (3) by subjecting the animals to stress, such as haemorrhage or hypoxia. Postnatal development of adrenergic mechanisms was studied with the aid of adrenergic agonist both in vivo and in vitro (helical strips cut from superior mesenteric artery were placed in an organ bath for isometric tension recordings). Recordings of spontaneous efferent splanchnic discharge permitted a more direct examination of autonomic regulation of the mesenteric vascular bed. The results indicate that the vascular bed supplied by the superior mesenteric artery and innervated by the efferent splanchnic nerve is actively involved in the cardiovascular responses to alterations in the cardiovascular regulatory system. Furthermore, this vascular bed may have an inappropriate response to both feeding and stress such that pathological changes in the gastrointestinal tract may result.

Aging↗
PubMed1979

Integrated cardiovascular responses to combined somatic and visceral afferent stimulation in newborn piglets.

Mean aortic pressure, arterial flow and heart rate response to interactions of afferent stimulation of the sciatic nerve (SNS) and carotid sinus stimulation by infusion (CSI) or inhibition by bilateral common carotid occlusion (BCCO) were studied in 25 newborn piglets under halothane-N2O anesthesia. Combined stimulation of the somatic and visceral afferents produced no heart rate changes. Combinations of pressor stimuli (BCCO and high frequency SNS) showed facilitation; femoral and renal resistances increased. However, combinations of depressor stimuli (CSI and low frequency SNS) showed occlusion. In combinations of pressor with depressor stimuli, the pressor pattern of responses dominated. Thus, dissimilar types of excitatory afferent inputs are capable of evoking facilitation in the neonatal cardiovascular regulatory system.

Afferent Pathways↗
PubMed1979

Cardiovascular and respiratory responses to right atrial injections of phenyl diguanide in pentobarbital-anesthetized newborn piglets.

The present series of experiments was designed to determine whether the piglet has mature cardiorespiratory responses to the administration of phenyl diguanide (PDG) similar to those reported in adult mammals. A total of 26 acutely instrumented piglets aged 2--23 days were lightly anesthetized with sodium pentobarbital. After control conditions were established, PDG was injected into the right atrium. Each animal was its own control for determination of presence and magnitude of aortic pressure, heart rate, respiratory rate and volume, and blood flow responses to test doses of PDG. A fall in blood pressure was observed in all animals within 2--4 sec after right atrial injection of PDG. Bradycardia occurred and a transient cardiac arrhythmia, consisting of 2nd and 3rd degree heart block, was observed in most animals; the latter has not been previously reported. Apnea followed by rapid shallow breathing was observed in most animals. This respiratory effect was more pronounced in the younger animals. After atropine, PDG elicited a monophasic rise in aortic pressure; the cardiac rhythm and rate changes were abolished. However, the apneic response was retained. Subsequent bilateral vagotomy abolished the hypotensive effect on PDG. Such results suggest the possibility that the piglet,s cardiorespiratory response to the administration of PDG may be evoked by stimulation of type J pulmonary receptors. These have been postulated to be responsible for the triad of responses of hypotension, bradycardia, and apnea seen in other species after PDG administration.

Anesthesia, Inhalation↗
PubMed1978

Integrated cardiovascular responses to combined somatic afferent stimulation in newborn piglets.

Heart rate, mean aortic pressure and arterial flow responses to interactions of afferent stimulation of the sciatic (SNS) and median nerve of the brachial plexus (BNS) were studied in 30 newborn piglets under halothane-N2O anesthesia. High frequency or intensity SNS or BNS stimulation resulted in pressor responses accompanied by significant increases in the femoral flow and carotid and renal resistance. Combined stimulation produced responses smaller than the estimated sum of the responses. Low frequency or intensity SNS or BNS resulted in depressor responses accompanied by significant decreases in mean femoral flow without change in heart rate; combined stimulation produced responses smaller than the estimated sum. When pressor and depressor patterns of stimulation were combined, pressor responses always dominated. The absence of facilitation to any combination of interactions implies that the cardiovascular regulatory system is not fully developed at birth and undergoes, therefore, postnatal maturation.

Afferent Pathways↗
PubMed1976

Cardiac and pulmonary failure secondary to adenotonsillar hypertrophy.

For over 15 years, upper respiratory tract obstruction due to adenotonsillar hypertrophy has been known to cause hypoxia, hypercapnia, increased pulmonary vascular resistance and thereby cor pulmonale and congestive heart failure. This is now an uncommon but not rare entity and three recent cases prompted this report. The typical patient is dyspneic with retractions, cyanosis, occasional periods of apnea and somnolence. Edema and hepatomegaly and at times splenomegaly are common. X-rays show cardiomegaly, which on electrocardiogram is found to involved mainly the right ventricle. The strict definition of cor pulmonale is right ventricular hypertrophy secondary to lung disease or abnormal pulmonary function, a definition that may logically be stretched to include abnormal respiratory function secondary to upper airway pathology. The mechanisms by which this occurs are generally agreed upon. Hypoxia has been demonstrated to cause pulmonary vasoconstriction. Acidosis and hypercapnia are thought by some to have the same effect. Pressure across the pulmonary vascular bed is also increased, as predicted by Poiseuille's law, by the high rate of blood flow required to maintain tissue oxygenation with poorly oxygenated blood. Conditions producing hypoxia of hypercapnia or both lead to hypertrophy and eventually to dilatation of the right ventricle. Three cases of children who underwent cardiac catheterization while suffering from cor pulmonale due to adenotonsillar hypertrophy are reported. Right ventricular pressure averaged 44/5, PAO2 72, pH 7.32, and PACO2 52. All were clinically improved following adenotonsillectomy. Cardiac catheterization was repeated in one case, with right ventricular pressure dropping from 44/5 to 21/2, pulmonary vascular resistance from eight units to three, and PACO2 from 62 to 44.

Adenoidectomy↗
PubMed1976

Patent ductus arteriosus with hypoplastic lung.

A median sternotomy approach was used for closure of patent ductus arteriosus associated with a hypoplastic right lung. The anterior approach to the left ductus is indicated if left thoracotomy is contraindicated.

Child, Preschool↗
PubMed1975

Right cervical aortic arch associated with a ventricular septal defect.

A patient with a right cervical aortic arch and ventricular septal defect is presented. This is the second reported case to have this rare combination of defects and the first to have survived corrective surgery. The x-ray film findings are discussed, and the similarity to the right posterior aortic arch is stressed.

Aortic Arch Syndromes↗
PubMed1975

Age-dependent cardiovascular effects of halothane anesthesia in neonatal pigs.

The cardiovascular effects of halothane anesthesia in a mixture of nitrous oxide and oxygen were studied on piglets 7 hr to 25 days of age. Blood pressure, heart rate and peripheral flows were recorded simultaneously in all animals. Body temperature and blood gas composition and pH were monitored and maintained within normal physiological limits for piglets. Inspired halothane concentration was kept at 1.0% during vascular surgery and then increased or decreased systematically. Halothane anesthesia depressed mean aortic pressure and increased carotid, femoral and renal resistances in piglets less than one week of age. These effects increased with increasing halothame concentrations from 0.25% to 1.5%. In older animals, mean aortic pressure changes were significant only at halothane concentrations above 1.0%, while peripheral resistances were unaffected. Although there was no concentration-dependent change in heart rate in either age group, heart rates were consistenly faster in younger animals.

Aging↗