1 / 39

Physiologic Adaptations at Birth

Physiologic Adaptations at Birth. Ma. Luisa de Villa- Manlapaz , MD, MHPEd February 8, 2011 ASMPH. Learning Objectives. To review the fetal circulation To learn the changes in the pulmonary and cardiovascular system that occur during birth

milly
Download Presentation

Physiologic Adaptations at Birth

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Physiologic Adaptations at Birth Ma. Luisa de Villa-Manlapaz, MD, MHPEd February 8, 2011 ASMPH

  2. Learning Objectives • To review the fetal circulation • To learn the changes in the pulmonary and cardiovascular system that occur during birth • To learn the hepatic adaptations in glucose metabolism, bilirubin metabolism, and vitamin K production • To learn how a newborn achieves thermoregulation

  3. Fetal Circulation • Placenta is responsible for exchange of gases, nutrients and metabolic waste products • Fetus receives blood from the placenta and returns it to the placenta

  4. Fetal Circulation • Blood flows from the placenta into the umbilical vein • The blood which contains a PO2 of approx 35 mmHg passes through the liver and ductusvenosus

  5. Fetal Circulation • Blood from ductusvenosus drains into the inferior vena cava  foramen ovale  left atrium

  6. Fetal Circulation • Superior vena cava drains de-oxygenated blood from the brain into the right atrium. •  right ventricle. • 90% of blood from RA shunted through the ductusarteriosus • 10% ejected to pulmonary artery  lungs

  7. Fetal Lungs and Circulation • Alveoli filled with lung fluid • Pulmonary arterioles constricted • Pulmonary blood flow diminished Click on the image to play video

  8. Neonatal Circulation • After birth, umbilical cord is cut • Systemic vascular resistance increases (BP in aorta increases) • Pulmonary vascular resistance decreases ((BP in lungs decreases)

  9. Lungs and CirculationAfter Delivery • Lungs expand with air • Fetal lung fluid leaves alveoli Click on the image to play video

  10. Lungs and Circulation • Pulmonary arterioles dilate • Pulmonary blood flow increases

  11. Lungs and Circulation • Blood oxygen levels rise • Ductusarteriosus constricts • Blood flows through lungs to pick up oxygen

  12. Normal Transition The following major changes take place within seconds after birth: • Fluid in alveoli absorbed and replaced by air • Umbilical arteries and vein constrict thus increasing blood pressure • Blood vessels in lungs relax, increasing pulmonary blood flow

  13. Baby cries and take first breath which help open alveoli • Surfactant keeps the alveoli from collapsing after they expand

  14. Metabolic Adaptation • In utero, fetus relies primarily on placental transfer of glucose and nutrients from mother to meet energy demands

  15. Metabolic Adaptation • Fetus stores glucose in the form of glycogen in last trimester – especially in last month of trimester

  16. After Birth Enzymes activate breakdown of glycogen back into glucose molecules Glucose released into bloodstream to maintain blood sugar Normal glucose utilization rate in fasting healthy term infant is 4-6 mg/kg/min

  17. Factors which influence glucose levels • Glycogen stores • Insulin levels • Glucose utilization • Premature baby • Infant of diabetic mother • Sick infant

  18. Thermoregulation • In utero, the fetus is in a warm and dark environment • Temperature is controlled

  19. At birth, newborn has to produce as much heat as much as is lost • THERMOREGULATION

  20. Normal Response to Cold Stress • Vasoconstriction in arms and legs • Increased movement and flexion of extremities • Brown fat metabolism

  21. Brown Fat Metabolism

  22. Heat loss • Occurs on a gradient from warmer to cooler Baby’s warm body to cooler air or surface • Heat loss accentuated by: • Wet skin • Cool air temperature • Drafts

  23. Kangaroo mother care • Mother provides warmth to the baby by skin to skin contact. • Provides easy access to the breasts, promoting breastfeeding

  24. Hepatic adaptation • Minor role of fetal liver – portal circulation shunted through the ductusvenosus • Majority of bilirubin pigment transferred unaltered across the placenta to the maternal circulation • Fetus has a high percentage of circulating red blood cells to utilize all available oxygen in a low oxygen environment

  25. PHYSIOLOGIC JAUDICE Increased bilirubin load on liver cell Increased erythrocyte volume Decreased erythrocyte survival Increased enterohepatic circulation of bilirubin Immature liver function

  26. Hepatic Adaptation • Liver manufactures clotting factors needed for blood coagulation • Several factors need Vitamin K for their production • Bacteria that produce Vitamin K are normally found in the gastrointestinal tract

  27. However, the gastrointestinal tract of the newborn is sterile • Therefore newborn cannot manufacture vitamin K which is needed to produce some clotting factors • Newborns are given Vitamin K either intramuscularly or orally at birth to prevent bleeding disorders

  28. Learning Objectives • To review the fetal circulation • To learn the changes in the pulmonary and cardiovascular system that occur during birth • To learn the hepatic adaptations in glucose metabolism, bilirubin metabolism, and vitamin K production • To learn how a newborn achieves thermoregulation

More Related