Cardiorespiratory Changes After Birth Dr. Harold Helbock

Generic Heart

The Cardiac Tube

The Adult Heart

Cardiac Outflow Anomalies Abnormal conditions compatible with fetal life are often Incompatible, or incapacitating to some degree, with postnatal life, including the adult. Chief among the hazards induced by cardiac anomalies is the distribution of inadequately oxygenated blood to the body.

Examples of Cardiac Anomalies Tetralogy of Fallot Stenosis of pulmonary artery Displacement of aortic opening to the right. Intraventricular opening Hypertrophy of right ventricle.

Patent Ductus Arteriosus Blood regurgitates from the aorta to the pulmonary artery and is taken back to the lungs. Examples of Cardiac Anomalies

Heart Rate in Labor

Characteristics of the Adult Pulmonary Respiratory System

Functions of the Lungs Gas Exchange Oxygen absorption Carbon Dioxide removal Immunologic Defense Metabolic Function Endocrine Function Peptide Activators Pulmonary capillary

The newborn must switch rapidly from intrauterine mechanisms to adult physiology. This process is referred to as transition and involves changes in both pulmonary and circulatory physiology. Transition Period from Prenatal To Postnatal Life

Normal Transition of Circulation from Pre- to Post- natal closed open expand closed

Differences in oxygenation system of the fetus to the newborn Bronchi/airways uterine artery Air sacks/alveoli placental sinusoids Pulmonary vein umbilical vein Oxygenated blood to the heart Pulmonary artery umbilical artery Venous blood to gas exchange organ Diaphragm maternal myocardium Move the gas to be exchanged

Events Happening at Birth First breath mm Hg vs mm Hg for normal breathing Closure of ductus arteriosus Functional and later anatomic closure Initially systemic and pulmonary pressures are equal Removal of fluid from the lungs

Protein molecules Chloride Major steps described in next slide

Removal of Lung Fluid at Birth 1.Fetus = Cl - pumps move fluid into potential air space. 2.Very little protein in potential air space liquid. 3.Result = osmotic pressure draws liquid from the alveolar space to the interstitium = circulation. 4.Newborn = Cl - pumping stops and Na + pump moves fluid out of alveoli. 5.Air pressure in the alveoli drives liquid out and into interstitium. 6.Expansion of the lung stretches open the pulmonary vessels and thereby reducing pulmonary vessel pressure and hydrostatic pressure. 7.Net result = liquid leaves air spaces and exits the interstitial space via the lymph and microcirculation.

The Apgar Score Assessment of transition Score012 Heart rate Respiratory effort Muscle tone Reflex irritability Color Absent Limp Absent Blue, pale Less than 100/min Slow, irregular Some flexion of extremities Grimace Body pink/extremities blue (acrocyanosis) More than 100/min Good, crying Active motion Grimace and cough or sneeze Completely pink

The First Hours of Life

The First Week of Life The infant is given vitamin K. –Eye drops are instilled to prevent blindness from bacterial infection. –Hepatitis B (a major cause of hepatic cancer) immunization. Feedings –Infant slowly increased volume of milk taken at each feeding until intake is about 1 fluid oz. per hour, on average. –Parents get a little more sleep, but not much!!  

Jaundice is a common problem on days 2-4 and longer if blood group incompatibilities exist. –Principle: post birth adaptation must take place in multiple systems, not just lungs and heart A good baby is a sick baby! BW ~ IQ and 1/CV disease risk, mom’s diet The First Week of Life