1 / 19

Neonatal and Paediatric Anatomy and Physiology

Neonatal and Paediatric Anatomy and Physiology. Dr Alison Chalmers Consultant Anaesthetist Queen Victoria Hospital. What you need to know. Fetal circulation and changes at birth Anatomical differences in the airway, head and spinal cord from the adult

fairly
Download Presentation

Neonatal and Paediatric Anatomy and Physiology

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. Neonatal and Paediatric Anatomy and Physiology Dr Alison Chalmers Consultant Anaesthetist Queen Victoria Hospital

  2. What you need to know • Fetal circulation and changes at birth • Anatomical differences in the airway, head and spinal cord from the adult • Physiological differences from the adult • Haematological and biochemical changes with age • Estimation of blood volume

  3. Ductus venosus Foramen ovale Ductus arteriosus Fetal circulation

  4. Changes at birth

  5. Changes at birth • First breath generates negative pressure • ↑ FRC ↓ PVR • Blood flows from right ventricle through lungs • ↑ SVR with clamping of umbilical vessels • Reversal of right to left flow through DA • Oxygen and ↓ PGE2 stimulates ductal constriction • ↑ LAP and ↑ SVR cause closure of the FO • DV closes passively as flow ceases

  6. Fetal haemoglobin • 2 ά chains and 2 λ chains • Binds 2,3-DPG less avidly than HbA • Shifts ODC to left (P50 2.4KPa) • Favours O2 transfer from mother to fetus • Gives up more O2 to fetal tissues than HbA • 80% circulating Hb at birth • Replaced within 3-5months by HbA

  7. CVS RV=LV at birth ↑ ratio of connective to contractile tissue Flat Starling curve Fixed SV Lungs Bronchial tree fully developed Alveoli develop fully after birth Compliant chest wall Diaphragmatic breathing Less ventilatory responses to PaO2 and PaCO2 Neonatal physiology

  8. Kidneys No of nephrons complete by birth RBF increases from 5% CO at birth to 20% at 1 month Low GFR; adult by 2 years Liver Immature enzymes CNS Pathways complete at birth Temp control High SA to body weight ratio Less SC fat Non shivering thermogenesis Neonatal physiology

  9. Airway Lungs CVS BMR CNS Temp regulation Fluid balance Pharmacology Paediatric anatomy and physiology

  10. Paediatric Airway

  11. Paediatric respiratory system • Diaphragmatic • Neonates – obligate nasal breathers • Increased respiratory rate • Very compliant chest wall – horizontal ribs • CC > FRC in normal breathing • Ventilatory response to CO2 reduced • BMR/O2 consumption high

  12. Paediatric cardiovascular system

  13. Paediatric nervous system • Spinal cord ends L3; recedes by adolescence • Immature BBB • Pronounced vagal reflexes

  14. Fluid balance • Blood volumes • Birth: 90ml/kg • Child: 80ml/kg • Teenager: 70ml/kg • Maintenance fluid requirements • 4ml/kg/h for first 10kg • 2ml/kg/h for next 10kg • 1ml/kg/h for each kg after

  15. Pharmacokinetics/dynamics • Lower plasma albumin levels up to 1 year • Renal and hepatic immaturity • MAC increased in neonates • Neonates sensitive to NMB; more resistant to sux

  16. Haematological changes with age • Hb • Birth: 14-22g/l, 3-6 months: 11-14, 6-12 years: 11.5-15.5 • WCC • Birth: 10-26 x109/l, 3-6 months: 6-18, 6-12: years 5-13 • Platelets – fairly stable between 150-500 x109/l • All vit K dependant clotting factors are low at birth – reach adult values by 6 months

  17. Biochemical changes with age • Albumin: low up to 1 year • Bilirubin: high at birth (17-170umol/l), normal adult levels by 1 month • Ca2+: low neonate (1.9-2.8mmol/l), normal adult levels by 1 year • T4: high neonate, falls to adult range steadily up to 10 years

  18. Any questions?

  19. Summary • Fetal circulation and changes at birth • Anatomical differences in the airway, head and spinal cord from the adult • Physiological differences from the adult • Haematological and biochemical changes with age • Estimation of blood volume

More Related