Reactivity of Cerebral Vessels to CO&lt;sub&gt;2&lt;/sub&gt; in the Newborn Rhesus Monkey

Reivich, Martin; Brann, Alfred W.; Shapiro, Harvey M.; Rawson, John A; Sano, Noboru

doi:10.1159/000114481

Cited by 53 publications

(20 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The correlation between total brain blood flow and Paco2 was similar to that described in other neonatal and adult animal species (26,27,29). Specifically, we demonstrated that the relationship becomes nonlinear below C 0 2 tensions of 20-25 mm Hg.…”

Section: Discussionsupporting

confidence: 86%

“…The increases in brain blood flow with hypercarbia is consistent with the observation of others (4,27,29,32). We did not extend our observations to Paco, ranges beyond 100 mm Hg; thus, we cannot determine whether the slope of the brain blood flowPace?…”

Section: Discussionsupporting

confidence: 84%

“…Paralysis was induced with 0.5 mg/kg of pancuronium and the ventilator was adjusted to obtain a predetermined Paco2 range of 35-45 mm Hg for the baseline blood flow measurement. Following the baseline determination, progressive hypocarbia was induced by increasing the ventilatory rate to achieve the predetermined P~c o~ ranges of [25][26][27][28][29][30][31][32][33][34][35][15][16][17][18][19][20][21][22][23][24][25], and less than 15 mm Hg. Following these three hypocarbic measurements, the ventilatory rate was returned to baseline and 15 min later, hypercarbia was induced by adding 15% COz to the inspired gases.…”

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

The Effects of Variations in Paco2 on Brain Blood Flow and Cardiac Output in the Newborn Piglet

et al. 1984

View full text Add to dashboard Cite

ABSTRAm. The acute effects of normoxemic hypocarbia and hypercarbia were examined in six newborn piglets. Brain blood flow was maintained during hypocarbia until extremely low Paco2 ( 4 5 mm Hg) levels were achieved at which time total brain and cerebral blood flow decreased significantly from baseline values. Blood flow to the thalamus, cerebellum and brain stem was unchanged from baseline conditions during hypocarbia. This suggests that the newborn brain is relatively insensitive to moderate degrees of hypocarbia. Extreme hypocarbia (Paco, e l 5 mm Hg) was associated with a significant increase in heart rate, accompanied by a significant decrease in mean arterial blood pressure; however, cardiac output was not significantly different from baseline determinations. Hypercarbia with normoxemia was associated with significant increases in total brain blood flow, with greater blood flow to the brain stem, cerebellum, and thalamus than to the cerebrum. The percentage of cardiac output received by the brain was also significantly increased, although total cardiac output was unchanged. This demonstrates that the newborn cerebral vasculature is sensitive to hypercarbia and that regional differences in sensitivity may account for the greater increments in blood flow to the caudal portions of the brain than that to the cerebrum. (Pediatr Res 18:1132-1136, 1984) Hyperventilation to extremely low Paco2 levels has been advocated as a form of therapy for pulmonary vasospasm in the human neonate (7,22). Hyperventilation has also been used in adults as a method of restoring autoregulation of the brain blood flow following brain injury (21). In the adult, there is no further reduction in cerebral blood flow below carbon dioxide tensions of approximately 20 mm Hg, presumably because ischemia induces metabolic changes in the brain that ovemde the C02 control of the cerebral vasculature (3,10,26 species whose brain maturation differs significantly from that of the term human neonate. The maturation of the newborn piglet brain is comparable to a human infant of 36-38 wk gestation (6, 23). Therefore, we utilized the newborn piglet to assess the acute effects of variations in Paco2 on brain blood flow and cardiac output, with a comparison of regional blood flow within the brain and the percentage of cardiac output received by the brain during hypo-and hypercarbia. MATERIALS AND METHODSSix, 1-to 4-day-old farm-bred piglets were subjects of this study. All piglets remained with the sows until the morning of the study. The weight of the piglets was 1.52 & 0.42 kg (mean +. SD).surgical procedures. All surgical procedures were performed under nitrous oxide inhalation anesthesia with local anesthesia using 1% xylocaine. A tracheotomy was performed and the piglets were ventilated with a pressure-limited Amsterdam infant ventilator using a gas mixture of 70% nitrous oxide and 30% oxygen. Polyvinyl catheters (OD127 ID86) were placed in the left axillary artery, abdominal aorta via the femoral artery and inferior vena cava via the femoral ...

show abstract

Section: Discussionsupporting

confidence: 86%

Section: Discussionsupporting

confidence: 84%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

The Effects of Variations in Paco2 on Brain Blood Flow and Cardiac Output in the Newborn Piglet

et al. 1984

View full text Add to dashboard Cite

show abstract

“…Thus, rabbit, dog, rat, and man all demonstrate postnatal increases in cerebral blood flow, and all have a brain that is relatively immature at birth. In contrast, species such as monkey or sheep, which are well developed at birth (14), have similar or higher levels of cerebral blood flow in the newborn compared with the adult (25)(26)(27).…”

Section: Increases In Cerebral Blood Flow Postnatally Regional Ormentioning

confidence: 98%

Local Cerebral Blood Flow in the Newborn Rabbit: An Autoradiographic Study of Changes during Development

Tuor

1991

Pediatr Res

View full text Add to dashboard Cite

“…100 g-' min-' mmHg Pa 0O21 (Purves & James, 1969: new-born lamb under sodium pentobarbitone anaesthesia, Pac02 > 40 mmHg) to 0*59 ml. 100 g-1 min' mmHg Pac 0-l (Reivich et al 1971: new-born Rhesus monkey under sodium pentobarbitone anaesthesia). These compare with 0-68 ml.…”

Section: Discussionmentioning

confidence: 99%

The effect of feeding on cerebral blood flow and oxygen consumption in the new‐born calf

Gardiner

1980

The Journal of Physiology

View full text Add to dashboard Cite

SUMMARY1. The effect of feeding on cerebral blood flow and oxygen consumption has been investigated in unrestrained calves between 7 and 28 days after birth.2. Cerebral blood flow was determined using an inert gas clearance technique, and oxygen consumption by the simultaneous measurement of the arterio-cerebral venous oxygen content difference.3. Cerebral blood flow increased during feeding from 74 + 4 to 116 + 9 ml. 100 g-1 min-' and reverted afterwards to the pre-feed level. No alteration in cerebral oxygen consumption occurred.4. Feeding was associated with an increase in mean arterial blood pressure and heart rate, and mild asphyxia.5. The sensitivity of the cerebral circulation to alterations in arterial PCO2 was investigated in seven calves under sodium pentobarbitone anaesthesia. In the range of arterial Pc02 15-75 mmHg the relationship was linear (r = 0-71; P < 0 001) with an average slope of 0-68 ml. 100 g-' min-mmHg Pa, co2 6. Increases in mean arterial blood pressure comparable to those occurring during feeding (96 + 6 to 159 + 8 mmHg) were produced by compression of the thoracic aorta in three calves under sodium pentobarbitone anaesthesia and were associated with an increase in cerebral blood flow from 48 + 4 to 76 + 8 ml. 100 g-1 min'. No significant change in calculated cerebral vascular resistance occurred during either feeding or aortic compression.7. These results suggest that the rise in blood pressure which occurs during feeding in the calf exceeds the autoregulatory capacity of the cerebral circulation.

show abstract

Reactivity of Cerebral Vessels to CO<sub>2</sub> in the Newborn Rhesus Monkey

Cited by 53 publications

References 0 publications

The Effects of Variations in Paco2 on Brain Blood Flow and Cardiac Output in the Newborn Piglet

The Effects of Variations in Paco2 on Brain Blood Flow and Cardiac Output in the Newborn Piglet

Local Cerebral Blood Flow in the Newborn Rabbit: An Autoradiographic Study of Changes during Development

The effect of feeding on cerebral blood flow and oxygen consumption in the new‐born calf

Contact Info

Product

Resources

About