Placental Respiration Research Articles

Making the Argument for Intact Cord Resuscitation: A Case Report and Discussion

We use a case of intact cord resuscitation to argue for the beneficial effects of an enhanced blood volume from placental transfusion for newborns needing resuscitation. We propose that intact cord resuscitation supports the process of physiologic neonatal transition, especially for many of those newborns appearing moribund. Transfer of the residual blood in the placenta provides the neonate with valuable access to otherwise lost blood volume while changing from placental respiration to breathing air. Our hypothesis is that the enhanced blood flow from placental transfusion initiates mechanical and chemical forces that directly, and indirectly through the vagus nerve, cause vasodilatation in the lung. Pulmonary vascular resistance is thereby reduced and facilitates the important increased entry of blood into the alveolar capillaries before breathing commences. In the presented case, enhanced perfusion to the brain by way of an intact cord likely led to regained consciousness, initiation of breathing, and return of tone and reflexes minutes after birth. Paramount to our hypothesis is the importance of keeping the umbilical cord circulation intact during the first several minutes of life to accommodate physiologic neonatal transition for all newborns and especially for those most compromised infants.

Placental respiration in a normal state and following bleeding in the mother

As for normal placental respiration, the author's research only confirmed the results already obtained earlier by Cohnstein and Luntz: it is known that the fetus borrows the oxygen it needs from the mother's blood and, in fact, the blood of the umbilical vein contains more oxygen, than the blood of the umbilical artery, while carbon dioxide, on the contrary, predominates in this latter.

Understanding the Risks and Benefits of Delivery Room CPAP for Term Infants.

* Abbreviations: CPAP — : continuous positive airway pressure DR — : delivery room FRC — : functional residual capacity NRP — : Neonatal Resuscitation Program Neonatal resuscitation is dependent on the successful transition from in utero circulation and placental respiration to reliance on pulmonary circulation. This focus on ventilation has been a hallmark of the Neonatal Resuscitation Program (NRP) since its inception >30 years ago.1 Continuous positive airway pressure (CPAP) was incorporated as a consideration into the algorithm of the NRP in the sixth edition of the program.2 In this month’s issue of Pediatrics , Smithhart et al3 evaluated >200 000 births from a single center and found an increase in pneumothorax in the late preterm and term population that received CPAP in the delivery room (DR) after the implementation of those guidelines. The risk of pneumothorax in this population was particularly increased in those infants receiving CPAP with 21% oxygen.3 This study raises the question of the safety of CPAP in the term and late preterm populations. Newborn transitional physiology is key to understanding why the results in the Smithhart et al3 study might be anticipated. Establishment … Address correspondence to Marya L. Strand, MD, MS, Cardinal Glennon Children’s Hospital, 1465 S Grand Blvd, St Louis, MO 63104. E-mail: marya.strand{at}health.slu.edu

Sexual dimorphism in the effect of maternal obesity on antioxidant defense mechanisms in the human placenta

IntroductionMaternal obesity creates an adverse intrauterine environment, negatively impacts placental respiration, is associated with a higher incidence of pregnancy complications and programs the offspring for disease in adult life in a sexually dimorphic manner. We defined the effect of maternal obesity and fetal sex on pro- and anti-oxidant status in placenta and placental mitochondria. Methods: Placental villous tissue was collected at term via c-section prior to labor from four groups of patients based on fetal sex and prepregnancy/1st trimester body mass index: lean - BMI 22.1 ± 0.3 (6 male, 6 female) and obese - BMI 36.3 ± 0.4 (6 male, 6 female). Antioxidant enzyme activity, mitochondrial protein carbonyls, nitrotyrosine residues, total and nitrated superoxide dismutase (SOD) and nitric oxide synthesis were measured. Results: Maternal obesity was associated with decreased SOD and catalase activity, and total antioxidant capacity (TAC), but increased oxidative (protein carbonyls) and nitrative (nitrotyrosine) stress in a sexually dimorphic manner. Placentas of lean women with a male fetus had higher SOD activity and TAC (p < 0.05) than other groups whereas obese women with a male fetus had highest carbonyls and nitrotyrosine (p < 0.05). Glutathione peroxidase and thioredoxin reductase activity increased with obesity, significantly with a male fetus, perhaps as a compensatory response. Conclusion: Maternal obesity affects oxidative stress and antioxidant activity in the placenta in a sexually dimorphic manner. The male fetus of a lean women has the highest antioxidant activity, a protection which is lost with obesity perhaps contributing to the increased incidence of adverse outcomes with a male fetus.

Circulatory changes associated with the closure of the ductus arteriosus in hatching emu (Dromaius novaehollandiae)

In developing avian embryos, the right and left ductus arteriosi (DA) allow for a shunt of systemic venous return away from the lungs to the body and chorioallantoic membrane (CAM). Unlike in mammals where the transition from placental respiration to lung respiration is instantaneous, in birds the transition from embryonic CAM respiration to lung respiration can take over 24h. To understand the physiological consequences of this long transition we examined circulatory changes and DA morphological changes during hatching in the emu (Dromaius novaehollandiae), a primitive ratite bird. By tracking microspheres injected into a CAM vein, we observed no change in DA blood flow between the pre-pipped to internally pipped stages. Two hours after external pipping, however, a significant decrease in DA blood flow occurred, evident from a decreased systemic blood flow and subsequent increased lung blood flow. Upon hatching, the right-to-left shunt disappeared. These physiological changes in DA blood flow correspond with a large decrease in DA lumen diameter from the pre-pipped stages to Day 1 hatchlings. Upon hatching, the right-to-left shunt disappeared and at the same time apoptosis of smooth muscle cells began remodeling the DA for permanent closure. After the initial smooth muscle contraction, the lumen disappeared as intimal cushioning formed, the internal elastic lamina degenerated, and numerous cells underwent regulated apoptosis. The DA closed rapidly between the initiation of external pipping and hatching, resulting in circulatory patterns similar to the adult. This response is most likely produced by increased DA constriction in response to increased arterial oxygen levels and the initiation of vessel remodeling.

Transition from fetal to neonatal circulation: Modeling the effect of umbilical cord clamping

Hemodynamics of the fetal to neonatal transition are orchestrated through complex physiological changes and results in cardiovascular adaptation to the adult biventricular circulation. Clinical practice during this critical period can influence vital organ physiology for normal newborns, premature babies and congenital heart defect patients. Particularly, the timing of the cord clamping procedure, immediate (ICC) vs. delayed cord clamping (DCC), is hypothesized to be an important factor for the transitory fetal hemodynamics. The clinical need for a quantitative understanding of this physiology motivated the development of a lumped parameter model (LPM) of the fetal cardio-respiratory system covering the late-gestation to neonatal period. The LPM was validated with in vivo clinical data and then used to predict the effects of cord clamping procedures on hemodynamics and vital gases. Clinical time-dependent resistance functions to simulate the vascular changes were introduced. For DCC, placental transfusion (31.3ml) increased neonatal blood volume by 11.7%. This increased blood volume is reflected in an increase in preload pressures by ~20% compared to ICC, which in turn increased the cardiac output (CO) by 20% (COICC=993ml/min; CODCC=1197ml/min). Our model accurately predicted dynamic flow patterns in vivo. DCC was shown to maintain oxygenation if the onset of pulmonary respiration was delayed or impaired. On the other hand, a significant 25% decrease in oxygen saturations was observed when applying ICC under the same physiological conditions. We conclude that DCC has a significant impact on newborn hemodynamics, mainly because of the improved blood volume and the sustained placental respiration.

Physician, poet, polymath and prophet: erasmus darwin a new window eighteenth-century child health care

Erasmus Darwin (1731–1802) is omitted from Still's History of Paediatrics. He was the foremost physician of his time, and a highly regarded poet. As a founder member of the Lunar...

Erasmus Darwin's Enlightened Views on Placental Function

In his major work “ Zoonomia”, Erasmus Darwin (1731–1802) devoted one chapter to the placenta, in which the new knowledge of the recently discovered element oxygen was applied to the functioning of this organ. He considered the “cavities” or “lacunae” in the placenta as the main areas for oxygenation of the fetal blood, as he thought them to be structurally comparable to the lungs and the gills of fish. He obviously was aware of species differences in the uterine arterial blood supply to the placenta between humans and cows, assuming a higher contractility of the vasculature in the latter species. The new evidence for a primarily respiratory role overshadowed ideas of a possible nutritive function of the placenta. Since Hunter's definitive demonstration of separate maternal and fetal blood circulations, nutritive functions of the placenta needed to be explained by transmembrane transport processes, which were unknown at that time. Instead Erasmus Darwin erroneously considered the amniotic fluid as the main source of nutrients for the fetus. His understanding of placental respiration found expression in his long poem on the history of life on earth.

Acoustic Analysis of Neonatal Breath Sounds: Changes during the Breath Adaptation Period.

The breath adaptation period of newborns involves the switch from placental respiration to pulmonary respiration and remarkable respiratory-physiological changes. We made an acoustic analysis of the changes over time in neonate breath sounds as one of the objective indicators of such changes.Using 30 children delivered transvaginally and 11 children delivered by caesarean section as subjects, breath sounds were recorded 2, 6, 12, 24, 48 and 72 h after birth, and frequencies were analyzed by a fast Fourier transform. From the power spectrum obtained, the percentage of the high frequency power at 500-700 Hz to the total power at 100-700 Hz (hereafter referred to as %500-700) was calculated for the study. In the children delivered transvaginally, %500-700 reached a peak 24 to 48 h after birth and tended to decrease gradually thereafter. The children delivered by caesarean section showed a peak 48 to 72 h after birth in many cases, although no fixed trend was seen. Various factors determine the frequency characteristics of breath sounds. Our study suggests that not only the influence of the discharge and the absorption of vesicular fluid, but also the lung compliance and changes in the functional residual volume, are involved with the changes in the frequency characteristics of the breath sounds of newborns from the period immediately after birth through the breath adaptation period.

The Red Pulp of the Spleen: Structural Basis of Blood Flow

In developing avian embryos, the right and left ductus arteriosi (DA) allow for a shunt of systemic venous return away from the lungs to the body and chorioallantoic membrane (CAM). Unlike in mammals where the transition from placental respiration to lung respiration is instantaneous, in birds the transition from embryonic CAM respiration to lung respiration can take over 24 h. To understand the physiological consequences of this long transition we examined circulatory changes and DA morphological changes during hatching in the emu (Dromaius novaehollandiae), a primitive ratite bird. By tracking microspheres injected into a CAM vein, we observed no change in DA blood flow between the pre-pipped to internally pipped stages. Two hours after external pipping, however, a significant decrease in DA blood flow occurred, evident from a decreased systemic blood flow and subsequent increased lung blood flow. Upon hatching, the right-to-left shunt disappeared. These physiological changes in DA blood flow correspond with a large decrease in DA lumen diameter from the pre-pipped stages to Day 1 hatchlings. Upon hatching, the right-to-left shunt disappeared and at the same time apoptosis of smooth muscle cells began remodeling the DA for permanent closure. After the initial smooth muscle contraction, the lumen disappeared as intimal cushioning formed, the internal elastic lamina degenerated, and numerous cells underwent regulated apoptosis. The DA closed rapidly between the initiation of external pipping and hatching, resulting in circulatory patterns similar to the adult. This response is most likely produced by increased DA constriction in response to increased arterial oxygen levels and the initiation of vessel remodeling.

Time of Onset of Effective Ventilation at Birth

A method for serial sampling of umbilical artery blood was described in a previous report. Another study using this method demonstrated that the umbilical artery blood becomes more asphyxial over the first 20 sec after birth, even though up to 5 breaths occurred over this time. In the present study, serial samples of umbilical artery blood were function obtained at slightly later intervals; the first samplings occurred at 11–41 sec and the second samplings at 22–59 sec. From 3 to 11 breaths occurred between birth and the second sampling. Unlike the results in the prior study, many infants showed a rising pH, a falling PCO&lt;sub&gt;2&lt;/sub&gt;, and a rising oxygen saturation from the first to the second sampling. When the results of one of the prior studies are combined with the present study, it appears that the fifth breath represents the approximate point of reversal of the trend from one of increasing asphyxia to one of improvement in blood gas values. The fifth breath usually occurred at 20–30 sec. It may be advantageous to allow the placental respiration to continue until the pulmonary respiration becomes effective by delaying cord clamping until 5 breaths have occurred or until 30 sec have elapsed.

Placental respiration in the immediate neonatal period

The umbilical cord was double clamped from one second before to 37 seconds after birth for 30 healthy term newborn infants. Twenty-eight of these infants were born vaginally, in the cephalic presentation, and 2 were born by elective cesarean section. Up to 6 breaths occurred before clamping. The mean umbilical vein (UV) minus umbilical artery (UA) differences were: for pH, 0.10 ± 0.04; for Pco2, −17 ± 11 mm. Hg; for Po2, 14 ± 6 mm. Hg. The mean UV-UA difference for oxygen content, calculated from the Po2 difference and the hemoglobin concentration, was 7.5 ± 3.6 vol. per cent. These differences showed no tendency to decrease from birth to 37 seconds. These data indicate that placental gas exchange is just as efficient at 37 seconds after delivery as it is at birth.

Experimental observations on the energy metabolism of human placenta.

SummaryOxygen consumption of histologically abnormal placentae was reduced but the effect on the fetus probably depends on the timing of the abnormality. A reduced placental respiratory rate, whether accompanied by no obvious histological change, or with the “senescent” changes of postmaturity, or by damage due to rehsus isoimmunization was associated with an adverse effect on fetal growth or wellbeing.Rotenone, antimycin A and cyanide, all inhibitors of mitochondrial electron transfer, markedly decreased the endogenous respiration of both normal and pathological placentae. Respiration was also reduced by from 35 per cent to 60 per cent by oligomycin, whereas it was increased by as much as 70 per cent by 2,4‐dinitrophenol. Oligomycin inhibition of endogenous respiration was largely offset by 2,4‐dinitrophenol. The results obtained showed that: (i) placental respiration was decreased in all the pathological conditions studied, (ii) the organization of the mitochondrial respiratory chain of placental cells might be similar to that of other normal tissues and (iii) placental respiration was coupled to energy conservation reactions both in normal and pathological conditions.

Postnatal placental respiration.

Developmental Medicine & Child NeurologyVolume 8, Issue 5 p. 607-608 POSTNATAL PLACENTAL RESPIRATION Peter M. Dunn, Peter M. Dunn Present address: Cardiovascular Research Institute, University of California Medical Center, San Francisco. 22. California. U.S.ASearch for more papers by this author Peter M. Dunn, Peter M. Dunn Present address: Cardiovascular Research Institute, University of California Medical Center, San Francisco. 22. California. U.S.ASearch for more papers by this author First published: October 1966 https://doi.org/10.1111/j.1469-8749.1966.tb01809.xCitations: 7AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article.Citing Literature Volume8, Issue5October 1966Pages 607-608 RelatedInformation

Considérations Sur Les érythroblastémies Du Fœtus Et Du Nouveau-Né Non Liées A Une Iso-Immunisation Par Le Facteur Rh

Summary1° Description of two cases of erythroblastosis secondary to other mechanisms than iso-immunisation.2° After reviewing classical facts about fœtal and placental respiration the authors stress the importance of anoxœmia in the pathogeny of fœtal erythroblastemia.3° Erythroblastemia should be considered as secondary in the diagnosis of hæmolytic disease of the new-born.