Regional Blood Flow Changes in Neonatal Pigs in Response to Hypercapnia, Hemorrhage and Sciatic Nerve Stimulation

Reddy, G.D.; Gootman, Norman; Buckley, N. M.; Gootman, Phyllis M.; Crane, L.A.

doi:10.1159/000240698

Cited by 23 publications

(33 citation statements)

References 8 publications

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“…However, in our studies in piglets, the fully integrated heart rate, arterial pressure, and regional flow response was not observed until the piglets were at least 2 weeks old (Buckley et al, 1976;Gootman et al, 1972;Reddy et al, 1974). Reflex bradycardia was rarely seen at the peak blood pressure rise during stimulation of sciatic nerve afferents or carotid sinus receptors (Buckley et al, 1976), although bradycardia did occur in response to direct stimulation of nucleus ambiguus (Gootman et al, 1972(Gootman et al, , 1978.…”

mentioning

confidence: 64%

Age-related cardiovascular effects of catecholamines in anesthetized piglets.

Buckley¹,

Gootman²,

Yellin³

et al. 1979

Circulation Research

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SUMMARY We studied cardiac and peripheral circulatory effects of graded doses of catecholamines (0.05-1.0 fig/kg) in piglets aged £ 1 day, 2-4 days, 1 week, 2 weeks, and 2.5-3 months, under anesthesia with pentobarbital. We evaluated cardiovascular function from simultaneous recordings of aortic pressure, ventricular pressure and its first derivative, heart rate, and phasic carotid and femoral blood flows. We calculated vascular resistance as the ratio of mean aortic pressure to mean flow. The age of onset of a given cardiovascular response was determined, and magnitudes of each type of response were compared among the age groups. Norepinephrine elevated the blood pressure at all doses in piglets of all ages, elicited reflex bradycardia only in older piglets, and increased carotid resistance. Epinephrine elevated the blood pressure at all doses in piglets less than 1 week old, but low doses lowered the blood pressure in piglets older than 1 week of age; resistance changes in the femoral and carotid circulations were variable except in the 2.5-3 month age group. Isoproterenol increased cardiac contractility at all doses in piglets of all ages and increased heart rate at low doses in piglets older than 2 days of age; however, blood pressure and femoral resistance decreases were age and dose dependent. There were age-related differences in the catecholamine dose required to elicit a given cardiac or peripheral circulatory effect and age-related differences in the direction and magnitude of such effects. These results provide evidence for differing rates of postnatal maturation of cardiovascular or-and /}-adrenergic mechanisms in swine. Ore Re* 45: 282-292, 1979

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mentioning

confidence: 64%

Age-related cardiovascular effects of catecholamines in anesthetized piglets.

Buckley¹,

Gootman²,

Yellin³

et al. 1979

Circulation Research

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“…It becomes~obvious ihat mean transit time expressed as ratio of pulmonary blood volume and flow must decrease considerably during development of piglets. Low volume-to-flow ratios can also be judged for the brain, kidney, and heart muscle by comparison of our results with relevant blood flow data in piglets (13,25,29,42).…”

Section: Age (Days)mentioning

confidence: 89%

Blood Volume and Hematocrit in Various Organs in Newborn Piglets

Linderkamp¹,

Berg²,

Betke³

et al. 1980

Pediatr Res

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Summaryborn to healthy sows at known full term. All piglets were suckledPlasma volume and red cell mass of various organs in piglets aged 24 hr (n = 7) and 7 (n = 6). and 14 (n = 6) days were measured using eemTc-labeled albumin and "Cr-labeled red blood cells. Organ activities were counted in a whole-body counter. Blood volume and hematwrit were calculated. The blood volumes in $/g varied markedly between various organs. The lowest blood volumes at 24 hr of age were found in skin (21.9 + 5.0 pl/g), brain (33.3 ~t 8.4), and skeletal muscle (35.5 + 7.4). The highest values at this age were noted in liver (670.0 + 89.1), lung (533.8 f 80.7), spleen (332.0 + 82.8), and kidney (300.6 + 55.5). Blood volumes of about 150 pl/g were observed in heart muscle and thyroid gland and those of about 100 pl/g in thymus and gastrointestinal tract.The total blood volume was 100.2 * 3.9 pl/g at 24 hr and remained unchanged during the first 2 wk of life. A significant decrease in relative blood volume with growth was noted in liver and lung ( P c 0.01), and in skeleton ( P < 0.05). The blood volume, contained in the great vessels outside the organs, increased from 29.5 * 5.5% of total blood volume at 24 hr to 31.2 * 5.7% at 7 days and to 38.2 k 7.5% at 14 days of life. The total body/venous hematwrit ratio was about 0.84. Accordingly, tissue hematwrits of most organs were below the venous hematocrit. Only in spleen was the tissue/ venous hematwrit ratio (TH/VH) higher than 1.0. TH/VH of brain, gastrointestinal tract, thyroid gland, and thymus approached unity. The lowest TH/VH was found in kidney (0.54 f 0.08 at day 1). In skin, the TH/VH decreased from 0.98 * 0.10 to 0.82 * 0.07 during the first 2 wk of life.by their mothers. They were not treated 4 t i iron. The right atrium was cannulated with polyethylen catheters via the right external jugular vein for injection and withdrawal of blood. Each piglet received local analgesia with procaine at the site of catheterization, but no systemic drugs. Two ml of blood were withdrawn from the catheter and centrifu ed for 5 min at 1000 x g. The red R blood cells were labeled with chromium (17). Salt-poor human serum albumin (25%) was labeled by means of a commercial kit for electrolytic preparation of -technetium (New England Nuclear Corp., North Billerica, MA). Each preparation of *"Tclabeled albumin was carefully checked for particulate matter, turbidity, and pH (6). Labeling efficiency was determined with trichloracetic acid and membrane filtration (14). Batches containing more than 1% of unbound -Tc were discarded. One postmix blood sample of 1 ml was taken 10 min after injection of labeled red blood cells and 5 min after injection of labeled albumin. Previous equilibration studies have shown that mixing of red blood cells and of albumin are complete within that period (16). Loss of albumin from the intravascular space has been found negligible in this short time. The piglets were killed immediately after the labeling and blood collecting procedure by injection of 2 mval KC1 via the ca...

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“…Additionally, Guignard et al (9) has shown that p 0 2 was the same in newborns with moderate or severe impairment of renal function, suggesting factors other than arterial oxygen tension may be important. Using the piglet, Reddy et al (14) observed an increase in renal blood flow secondary to moderate degrees of hypercapnea and acidosis and a decrease in renal blood flow with severe hypercapnea and acidosis.…”

Section: Discussionmentioning

confidence: 99%

Effects of Asphyxia on Renal Function in the Newborn Piglet

et al. 1978

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Summarveter was advanced into the abdominal aorta from the right femoral artery. This catheter was used for the determinatioiof This investigation was undertaken to determine the nature of blood pressure and heart rate and for sampling arterial blood. acute alterations in renal function following the production of Radioactive injections were made through a third h~~o x e m i a , h~~e r c a r b i a , and acidosis in newborn piglets 6-96 catheter (PE-90) placed in the ascending aorta by way of the left hr of age* After com~letion of the procedure piglets carotid artery. The urinary bladder was isolated through a small were allowed to recover from the effects of anesthesia. When midline abdominal incision and catheterizedThe posidead space was increased arterial Oxygen tion of all catheters was confirmed by inspection at the end of decreased whereas arterial carbon dioxide tension and hydrogen the experiment. ion concentration increased. There was little change in glomerAfter suturing the skin incisions all wounds were infiltrated ular fdtration rate. Total renal blood flow decreased and renal with lidocaine. Anesthesia was discontinued and the piglets were increased * 78 mm Hg/ placed upright in a supporting sling and allowed to recover from liter/mm/m2 to 1422 * 504). There was no change in distribu-anesthesia for hr. During the surgical procedure and the tion of intrarenal blood flow. Sodium excretion and urinary flow experiment the piglets were maintained at a body temperature rate demonstrated significant parallel increases following the of 380 using a Merco infant Under these conditions the increase in dead space. Plasma renin concentration increased animals remained calm and undisturbed in the sling, often from 67 to 110 ng/ml.sleeping during the experiment. Rectal temperature was continuously monitored using a Yellow Springs thermister. After Speculation completion of the surgical procedure the piglets were intubated Hypoxia, hypercarbia, and acidosis produced changes in renal with a 3.5 mm Portex endotracheal tube. Baseline determinafunction in newborn piglets. Therapeutic approaches to the tions were made and then a dead space 45 cc/ newborn human with respiratory distress must consider the kg) Was added to the tube in order to produce potential for modifications of renal function which may be hypoxia and hypercarbiadetrimental to the infant.Tritiated methoxy inulin (1 pCi/ml) was infused into the femoral vein at a rate of 0.04 ml/min beginning 1 hr before the onset of the experiment. During each clearance period urine The effects of respiratory distress on cardiopulmonary func-collections were made in preweighed flasks under oil. Urine tion in the newborn infant have been extensively studied. flow rate was estimated from the change in weight without However, renal function during this disease process has not ~0"ection for Specific gravity. Urine Was collected for determibeen adequately described. Recent observations have indicated nation of i n~l i n and sodium and potassium concentration. Artethat newbo...

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Regional Blood Flow Changes in Neonatal Pigs in Response to Hypercapnia, Hemorrhage and Sciatic Nerve Stimulation

Cited by 23 publications

References 8 publications

Age-related cardiovascular effects of catecholamines in anesthetized piglets.

Age-related cardiovascular effects of catecholamines in anesthetized piglets.

Blood Volume and Hematocrit in Various Organs in Newborn Piglets

Effects of Asphyxia on Renal Function in the Newborn Piglet

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