Blood Volume in Newborn Piglets: Effects of Time of Natural Cord Rupture, Intra-Uterine Growth Retardation, Asphyxia, and Prostaglandin-Induced Prematurity

Linderkamp, Otwin; Betke, Klaus; Güntner, Monika; Jap, Giok H; Riegel, K; Walser, K

doi:10.1203/00006450-198101000-00013

Cited by 20 publications

(6 citation statements)

References 25 publications

(45 reference statements)

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“…Parameters for the lumped circulation system are listed in table 2 and scaled from [6] by taking into account the dimensions of the neonatal porcine heart. For example, the total blood volume is around 80 ml for a newborn piglet [47], much less than in an adult porcine (67.2 ± 4.12 ml kg −1 ) [48], the valvular area in a newborn heart is about one-tenth of the area in an adult heart [49][50][51], and the diameter of blood vessel is also much smaller in the newborn piglet compared with an adult porcine [52], which suggests that under similar pressure loadings, the vessel compliance, calculated as ΔV/ΔP will be much less in a newborn porcine because of much smaller ΔV in a newborn piglet. Parameters for passive strain energy function and the maximum active tension from myocytes (T max ) are listed in table 3.…”

Section: Boundary Conditions and Implementationsmentioning

confidence: 99%

Effect of myofibre architecture on ventricular pump function by using a neonatal porcine heart model: from DT-MRI to rule-based methods

et al. 2020

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Myofibre architecture is one of the essential components when constructing personalized cardiac models. In this study, we develop a neonatal porcine bi-ventricle model with three different myofibre architectures for the left ventricle (LV). The most realistic one is derived from ex vivo diffusion tensor magnetic resonance imaging, and other two simplifications are based on rule-based methods (RBM): one is regionally dependent by dividing the LV into 17 segments, each with different myofibre angles, and the other is more simplified by assigning a set of myofibre angles across the whole ventricle. Results from different myofibre architectures are compared in terms of cardiac pump function. We show that the model with the most realistic myofibre architecture can produce larger cardiac output, higher ejection fraction and larger apical twist compared with those of the rule-based models under the same pre/after-loads. Our results also reveal that when the cross-fibre contraction is included, the active stress seems to play a dual role: its sheet-normal component enhances the ventricular contraction while its sheet component does the opposite. We further show that by including non-symmetric fibre dispersion using a general structural tensor, even the most simplified rule-based myofibre model can achieve similar pump function as the most realistic one, and cross-fibre contraction components can be determined from this non-symmetric dispersion approach. Thus, our study highlights the importance of including myofibre dispersion in cardiac modelling if RBM are used, especially in personalized models.

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Section: Boundary Conditions and Implementationsmentioning

confidence: 99%

Effect of myofibre architecture on ventricular pump function by using a neonatal porcine heart model: from DT-MRI to rule-based methods

et al. 2020

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“…The mean ± S.E. % of total blood volume removed at study completion [based upon an estimated blood volume of 90 cc/kg (17)] was 50 ± 3% (range 41-61). Alterations in the frequency of respirator cycling maintained a constant Paco2.…”

Section: Summary Speculationmentioning

confidence: 99%

Brain Blood Flow and O2 Delivery during Hemorrhagic Hypotension in the Piglet

Laptook

Stonestreet

1983

Pediatr Res

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- MATERIALS AND METHODSand/or hypocapnea. The first objective of the current study is to demonstrate the effect of hypotension on brain blood flow by maintaining a constant Paco2 with controlled ventilation.In adult animals during hypotension regional blood flow responses reveal conflicting results. Using the microsphere technique in adult mongrel dogs (22) and cynomologus monkeys (6) after induced hypotension (via hemorrhage in the former and pharmacologic means in the latter) no differences in regional blood flow to the brain were detected. In contrast, during hemorrhagic hypotension in .adult dogs (18), blood flow (microspheres) was preferentially maintained to the medulla. In the piglet (15) we have shown that during hemorrhagic hypotension, regional differences in brain blood flow reduction did occur. The reduction was most pronounced in the cerebrum, less in the cerebellum, and least in the brainstem. The presence of hypotension and hypocapnea made it undertain as to which was responsible for the regional differences in reduced perfusion. Therefore, the second objective of the present study is to determine if regional differences in brain blood flow reduction and oxygen delivery exist when the mean arterial blood pressure is altered during hemorrhagic hypotension under conditions of controlled ventilation. Summary SpeculationNewborn piglets subjected to profound hypotension demonstrate regional differences in the reduction of brain blood flow. Cranial window studies of the microvasculature in adult cats clearly demonstrate that precapillary vessels in the brain do not respond in an identical manner to hypotension but rather react in a size dependent fashion. The observed differences in brain regional blood flow are possibly a manifestation of the relative composition (with respect to vessel size) of the regional parenchymal arterial beds.We have previously demonstrated regional differences in brain blood flow reduction when hemorrhagic hypotension was induced in spontaneously breathing newborn piglets. Both the mean arterial blood pressure and Paco2 correlated with the changes in brain blood flow. To determine if changes in brain blood flow during hypotension can be attributed to alterations of mean arterial blood pressure alone, eight newborn piglets were studied under conditions of controlled ventilation. Regional brain blood flow was measured by microspheres and the blood pressure was varied by phlebotomy. After baseline determinations, three measurements of blood flow were performed during hypotension. Hypotension produced a significant reduction in blood brain flow confirming the independent effect of mean arterial blood pressure in autoregulation of cerebral circulation. Significantly different regional blood flow responses occurred in response to hypotension (P < 0.05).The % reduction from control blood flow was greatest to the cerebrum, less to the cerebellum, and least to the brainstern. Furthermore, the blood flow was consistently decreased in the cerebral hemispheres during the entire exposure t...

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“…Further more, these piglets were all born on local farms where the deliveries are often unat tended. Only in 2 of the piglets (Hb 12.2 and 7.0 g; 100 ml-1) had the umbilicus been clamped soon after birth to prevent bleeding which is a well-known problem [18,19]. Nor wegian landrace pigs are thoroughbred and extremely fast growing [Norwegian Veterina ry Institute, personal commun.].…”

Section: Intervention Studymentioning

confidence: 99%

Haemoglobin Is Inversely Related to Plasma Lactate and Heart Rate in the Newborn Piglet

et al. 1996

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It has been hypothesized that an increased level of plasma lactate (La), the product of anaerobic glycolysis, may identify infants with anaemia and early tissue hypoxia. In the newborn piglet, a frequently used model in experimental neonatology, there is a substantial decrease in haemoglobin (Hb) during the first days of life. We have investigated whether a low level of Hb is associated with an increased level of La in the newborn piglet. Arterial blood gas, Hb, glucose, La, and continuous blood pressure and heart rate (HR) recordings were obtained from 66 newborn piglets. In 4 additional piglets recordings were obtained before isovolemic anaemia, during isovolemic anaemia, and after retransfusion of packed red cells. A low concentration of Hb in the newborn piglet correlates with an increased level of La as well as with an increased HR. A reduction of Hb causes an increase in La and in HR. We hypothesize that increased La and increased HR are caused by mild hypoxia due to normal, low Hb levels in the apparently healthy, resting newborn piglet.

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Blood Volume in Newborn Piglets: Effects of Time of Natural Cord Rupture, Intra-Uterine Growth Retardation, Asphyxia, and Prostaglandin-Induced Prematurity

Abstract: Pediatr. Res. 15: 53-57 (1981) asphyxia natural cord rupture blood volume prostaglandin Fa intra-uterine growth retardation

Cited by 20 publications

References 25 publications

Effect of myofibre architecture on ventricular pump function by using a neonatal porcine heart model: from DT-MRI to rule-based methods

Effect of myofibre architecture on ventricular pump function by using a neonatal porcine heart model: from DT-MRI to rule-based methods

Brain Blood Flow and O2 Delivery during Hemorrhagic Hypotension in the Piglet

Haemoglobin Is Inversely Related to Plasma Lactate and Heart Rate in the Newborn Piglet

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