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Embed code for: Human Fetal Circulation for nursing
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Characteristics of Neonatal Respiration: Characteristics of Neonatal Respiration Normal rate – 30 – 50/ mt Nature – chest movement Initially shallow, irregular Later, deep & regular Periodic respiration --- normal breathing In deep – regular resp Obligatory nose breathers Danger signs - Rate <30 or > 60/ mt at rest Dysnea, cyanosis >ed use of IC muscles (Resp distress) Noisy breathing (?fluid/ other obstruction) * CIRCULATORY ADAPTATIONS: CIRCULATORY ADAPTATIONS: CIRCULATORY ADAPTATIONS UMBILICAL CORD – CUT & CLAMPED <ed blood flow <ed pulm vascular resistance <ed pressure on Rt side VENTILATION Pulm vascular dilatation, <ed resistance & >ed flow >ed blood flow to the Lt side Lung expansion Closure of foramen ovale, Ductus venosus, ductus arteriosus >ed pressure on the Lt side FOETAL SHUNT REVERSED * CIRCULATORY CHANGES: CIRCULATORY CHANGES HR – Initially 175 – 180/ mt---120 – 150/ mt BP – 74/47 mm Hg (resting) >es by 20 Heart murmur – Slight cardiomegaly - Immediately after birth Last for a few days * THERMOREGULATION Newborns come from a warm environment to the cold and fluctuating temperatures of this world. They are naked, wet, and have a large surface area to mass ratio, with variable amounts of insulation, limited metabolic reserves, and a decreased ability to shiver. * Physiologic mechanisms for preserving core temperature include vasoconstriction (decrease blood flow to the skin), maintaining the fetal position (decrease the surface area exposed to the environment), jittery large muscle activity (generate muscular heat) * The latter occurs in "brown fat" which is specialized adipose tissue with a high concentration of mitochondria designed to rapidly oxidize fatty acids in order to generate metabolic heat. The newborn capacity to maintain these mechanisms is limited, especially in premature infants. * Fatma Elsobky * As such, it is not surprising that some newborns may have problems regulating their temperature. As early as the 1880s, infant incubators were used to help newborns maintain warmth, with humidified incubators being used as early as the 1930s. * Fatma Elsobky * Basic techniques for keeping newborns warm include keeping them dry, wrapping them in blankets, giving them hats and clothing, or increasing the ambient temperature. * Fatma Elsobky * More advanced techniques include incubators (at 36.5°C), humidity, heat shields, thermal blankets, double-walled incubators, and radiant warmers while the use of skin-to-skin "kangaroo mother care" interventions for low birth-weight infants have started to spread world-wide after its use as a solution in developing countries. * Fatma Elsobky * GIT ADAPTATIONS: GIT ADAPTATIONS Mature mostly all over. Some salivary glands functional Liver immature at first. Deficient in – Physiological jaundice ProthrombinGlucoronyl enzyme & coagulation factors Hypoglycemia Stomach capacity – 90 ml, Bleeding tendency Glycogen stores emptying 2 ½ - 3 hrs, rapid peristalsis & digestion Enzymes – Adequate for proteins & simple sugars. Pancreatic amylase deficient * Bowel movement – Frequent (7- 10), semi solid Intestines – Larger in relation to body size, more no of secretory glands, more surface area for absorption Cardio-esophageal sphincter – Relaxed ( Regurgitation) Meconium – (Amniotic fluid, mucus, bile pigments, fatty acids, epithelial cells , blood) – First 3 days Transitional stool – By 4 th day (colour, consistency, odor) * RENAL ADAPTATIONS: RENAL ADAPTATIONS Structurally mature, functionally immature Frequent voiding (20) for 15 – 20 days susceptible to dehydration, acidosis, electrolyte imbalance concentrate urine no colour, no smell till 2 – 3 months Total volume – 200 – 300ml/ 24 hrs (15 to 30 ml /Kg per 24 hrs). * IMMUNOLOGIC ADAPTATIONS: IMMUNOLOGIC ADAPTATIONS Immunoglobins – Foetus synthesizes immunoglobins – 20 th week of gestation. (IgM, IgG and IgE) IgG crosses placenta. IgA secreted in colostrum IgM does not cross placenta. Surface protection - Vernix caseosa, skin & mucus membrane. * NEUROLOGICAL ADAPTATIONS: NEUROLOGICAL ADAPTATIONS Newborn’s brain – 25% of adult size. Incomplete myelination of nerve fibres. Primitive reflexes disappear when nervous system develops. * SENSORY ADAPTATION SENSORY ADAPTATION.. Hearing – Startle reflex, crying Low frequency voices <es cry & motor activity Can identify mother’s voice by 3 days of life Smell – Reacts to strong smell Can identify mother’s milk * SENSORY ADAPTATION SENSORY ADAPTATION.. Taste - Can distinguish taste Taste buds – on tip of tongue in early life Touch – Can perceive touch all over body Responds to patting, stroking, rubbing Cries with painful stimuli * HEMATOPOIETIC SYSTEM: HEMATOPOIETIC SYSTEM RBC – 5 – 6.5 milliion/ mm cube. <es to 4 – 5 million by 10 th day Reticulocytes – 4 – 6%. <es to 2% Hemoglobin – 16 – 20 gm%. <es to 15 gm% WBCs – 20,000/mm cube at birth. <es to 10,000/ mm cube by 3 rd day. Then gradual rise till end of the week S Bil – 1-2 gm% (Immature liver) * Normal vital signs at birth Heart rate= 120-140 beat/min Blood pressure= 65/41 mmHg Respiratory rate= 30-60 breath/min Temperature= Axillary 35.5-37oC. Oxygen saturation (SpO2 )= >93% * * * * * * * * * * * * Mahdia Shaker Mahdia Shaker Mahdia Shaker Mahdia Shaker Mahdia Shaker Mahdia Shaker Mahdia Shaker Mahdia Shaker ADJUSTMENTS TO EXTRA UTERINE LIFE By : Dr/ Fatma Elsobky Learning Objectives * * At the end of the lecture the students should be able to: Define adjustment of respiratory system Describe newborn Thermoregulation . Explain circulatory changes. Define GIT changes. Who is a new born? * Who is a new born? ‘ A live baby born either normal or as high risk irrespective of gestational age’ * Transition from intrauterine to extra uterine life. Dependence to independence Bio-psycho-social adaptation. Newborn’s adjustment depends upon: Genetic composition Competency of recent Intrauterine environment Care during birth Care during neonatal period Physiological & Psychological basis of Newborn adaptation Fetal Circulation Fetal circulation (prenatal circulation) differs from adult circulation in several ways and is designed to ensure a high oxygen blood supply to the brain and myocardium of the fetus. Fetal Circulation Mahdia Shaker * Characteristics of fetal circulation Placenta is the source of oxygen for the fetus, it has 2 arteries and 1 vein. Fetal lungs receive less than 10% of the blood volume ; lung don’t exchange gas. Right atrium of fetal heart is the chamber with the highest oxygen concentration. The three openings that close at birth are: Ductus Arteriosus connects the pulmonary artery to the aorta, bypassing the lungs Ductus Venosus connects the umbilical vein and the inferior vena cava bypassing the liver. Foramen Ovale is the opening between right and left atrias of the heart , bypassing the lungs. Pattern of fetal circulation Oxygenated Blood is carried from placenta through the umbilical vein and enters the inferior vena cava thought the Ductus Venosus . This permits most of the highly oxygenated blood to go directly to the right atrium , by passing the liver. This right atrial blood flows directly into the left atrium through the foramen ovale an opening between the right and the left atriums . From the left atrium blood flows directly into left ventricle and the Aorta through the subclavian arteries , to the cerebral and coronary arteries , resulting in the brain and the heart receiving the most highly oxygenated blood . Deoxygenated blood returns from the heart and the arms through the superior vena cava, enters the right atriums and passes into the right ventricle. Blood from the right ventricle flow into pulmonary artery, but because fetal lungs are collapsed, the pressure in the pulmonary artery is very high . Because pulmonary resistance is high , most of the blood passes into the distal aorta through the Ductus Arteriosus, which connects the pulmonary artery and the aorta distal to the origin of the subclavian arteries. From the aorta blood flows to the rest of the body. * Increase in pressure of the left atrium, decrease pressure in right atrium, causing closure of foramen ovale. Pulmonary resistance is less than systematic resistance so there is left-to-right shunting resulting in closure of the ductus arteriosus. What after birth??? The most important physiologic change required of the neonate is the transition from fetal or placental circulation to independent respiration out of the uterus. “Fetal Asphyxia” is considered to be the most fatal abnormal stressor after labor . Respiratory Adjustment At birth, the baby's lungs are filled with lung liquid. The newborn is expelled from the birth canal, its central nervous system reacts to the sudden change in temperature and environment. This triggers it to take the first breath, within about 10 seconds after delivery. With the first breaths, there is a fall in pulmonary vascular resistance, and an increase in the surface area available for gas exchange. * Fatma Elsobky * Over the next 30 seconds the pulmonary blood flow increases and is oxygenated as it flows through the alveoli of the lungs. Oxygenated blood now reaches the left atrium and ventricle, and through the descending aorta reaches the umbilical arteries. Oxygenated blood now stimulates constriction of the umbilical arteries resulting in a reduction in placental blood flow. * Fatma Elsobky * As the pulmonary circulation increases there is an equivalent reduction in the placental blood flow which normally ceases completely after about three minutes. These two changes result in a rapid redirection of blood flow into the pulmonary vascular .The increase in pulmonary venous return results in left atrial pressure being slightly higher than right atrial pressure, which closes the foramen ovale. * Fatma Elsobky * The flow pattern changes results in a drop in blood flow across the ductus arteriosus and the higher blood oxygen content of blood within the aorta stimulates the constriction and ultimately the closure of this fetal circulatory shunt. * Fatma Elsobky * All of these cardiovascular system changes result in the adaptation from fetal circulation patterns to an adult circulation pattern. During this transition, some types of congenital heart disease that were not symptomatic in utero during fetal circulation will present with cyanosis or respiratory signs. * Fatma Elsobky * Following birth, the expression and re-uptake of surfactant, which begins to be produced by the fetus at 20 weeks gestation, is accelerated. Expression of surfactant into the alveoli is necessary to prevent alveolar closure (atelectasis). At this point, rhythmic breathing movements also commence. * Fatma Elsobky * If there are any problems with breathing, management can include stimulation, bag and mask ventilation, intubation and ventilation. Cardio-respiratory monitoring is essential to keeping track of potential problems. Pharmacological therapy such as caffeine can also be given to treat apnea in premature newborns. * Fatma Elsobky * Factors opposing first breath: Factors opposing first breath : Alveolar surface tension Viscosity of lung fluid Degree of lung compliance Mucus, blood, meconium, amniotic fluid * Mahdia Shaker Mahdia Shaker Mahdia Shaker Mahdia Shaker Mahdia Shaker Mahdia Shaker Mahdia Shaker Mahdia Shaker * * * * * * * * * * the subclavian arteries , to the cerebral and coronary arteries , resulting in the brain and the heart receiving the most highly oxygenated blood . Deoxygenated blood returns from the heart and the arms through the superior vena cava, enters the right atriums and passes into the right ventricle. Blood from the right ventricle flow into pulmonary artery, but because fetal lungs are collapsed, the pressure in the pulmonary artery is very high . Because pulmonary resistance is high , most of the blood passes into the distal aorta through the Ductus Arteriosus, which connects the pulmonary artery and the aorta distal to the origin of the subclavian arteries. From the aorta blood flows to the rest of the bo