Podcast
Questions and Answers
What causes the closure of the foramen ovale in newborns?
What causes the closure of the foramen ovale in newborns?
How long does it typically take for the ductus arteriosus to functionally close after birth?
How long does it typically take for the ductus arteriosus to functionally close after birth?
What is the primary mechanism of thermogenesis in newborns?
What is the primary mechanism of thermogenesis in newborns?
Which factor does NOT predispose newborns to excessive heat loss?
Which factor does NOT predispose newborns to excessive heat loss?
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What is the recommended nursery room temperature to prevent heat loss in newborns?
What is the recommended nursery room temperature to prevent heat loss in newborns?
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What type of heat loss occurs when heat is transferred from the body to cooler objects nearby?
What type of heat loss occurs when heat is transferred from the body to cooler objects nearby?
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What should be done immediately after birth to reduce heat loss from evaporation?
What should be done immediately after birth to reduce heat loss from evaporation?
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What is the main physiological change that starts to close the ductus arteriosus in newborns?
What is the main physiological change that starts to close the ductus arteriosus in newborns?
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What initiates the newborn's critical adaptation to extrauterine life?
What initiates the newborn's critical adaptation to extrauterine life?
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Which factor does NOT stimulate the breathing of a newborn?
Which factor does NOT stimulate the breathing of a newborn?
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What role does surfactant play in a newborn's respiratory system?
What role does surfactant play in a newborn's respiratory system?
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Which of the following methods should NOT be used for tactile stimulation of a newborn?
Which of the following methods should NOT be used for tactile stimulation of a newborn?
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What physiological change occurs in the newborn's circulatory system after the umbilical cord is clamped?
What physiological change occurs in the newborn's circulatory system after the umbilical cord is clamped?
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What effect does inspired oxygen have on a newborn's pulmonary vessels?
What effect does inspired oxygen have on a newborn's pulmonary vessels?
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Which of the following describes the process of fetal lung fluid removal during birth?
Which of the following describes the process of fetal lung fluid removal during birth?
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What happens to pulmonary blood flow as the pulmonary vascular resistance decreases in a newborn?
What happens to pulmonary blood flow as the pulmonary vascular resistance decreases in a newborn?
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Study Notes
Newborn Adjustments
- Newborn adaptation to extra-uterine life is critical
- Respiration initiation is the most crucial adaptation
Respiratory System
- Chemical factors (hypoxemia, hypercarbia, low pH) stimulate breathing
- Thermal factors stimulate breathing (cold environment)
- Skin sensory impulses trigger medulla's respiratory centre
- Tactile factors also stimulate breathing (birth canal descent, tapping feet or rubbing torso)
Newborn Respiration
- Fetal lung fluid removal involves chest compression during birth canal passage and lymphatic/pulmonary capillary absorption
- Alveoli expansion occurs with breathing initiation
- Surfactant crucial for keeping alveoli expanded
Newborn Management
- Tactile stimulation is critical (dry infant immediately after birth; rub/flick soles if needed; do not slap)
Newborn Circulation
- Circulatory changes allow blood flow through lungs
- Pressure changes in the heart, lungs and vessels
- Functional closure of fetal shunts (Foramen ovale, Ductus arteriosus, Ductus venosus)
Sequential Circulatory Changes in the Newborn
- Inspired oxygen dilates pulmonary vessels
- Pulmonary vascular resistance decreases, pulmonary blood flow increases
- Pressure in RA, RV, and pulmonary arteries decreases
- Gradual increase in systemic vascular resistance after cord clamping
Further Circulatory Changes in the Newborn
- LA pressure higher than RA pressure closes the foramen ovale
- Increasing pulmonary blood flow and decreasing pulmonary vascular resistance closes the ductus arteriosus
Thermoregulation
- Newborns rely on nonshivering thermogenesis (metabolism of brown fat)
- Brown fat is located in inter-scapular regions, axillae, thoracic inlet and around kidneys increasing metabolic rate
- Increased metabolic rate in the brain, heart and liver
Heat Loss Mechanisms
- Convection: heat loss from body to air (maintain nursery room temperature at 24°C and wrap baby)
- Radiation: heat loss from body to cooler surfaces nearby (place nursery cribs and examination tables away from windows)
- Evaporation: liquid on the body converting to vapour (delay bathing and dry the newborn immediately after birth)
- Conduction: heat loss from body to surfaces in direct contact (use warmed crib, measuring tape and stethoscope)
Factors Predisposing Newborns to Excessive Heat Loss
- Large surface area
- Thin layer of adipose
- Inability to shiver
- Immature thermoregulatory center in the brain
- Blood vessels close to the skin
Hemopoietic System
- Blood volume depends on placental transport
- Full-term newborns have an approximate blood volume of 80-85 mL/kg
- Average newborn blood volume is 300 +/- 100 mL
Fluid and Electrolytes
- Newborn body weight is 73% fluid (Adult is 58%)
- Infants have a higher ratio of extracellular fluid than adults
- Infants have higher total body Na+ and Cl+
- Infants have lower total body K+, Mg++, and phosphate
Implications
- Fluid exchange rate in newborns is faster than in adults
- Newborn metabolism rate is twice as great related to body weight
- Acid forms quickly, leading to rapid acidosis development
- Immature kidneys cannot concentrate urine to conserve body fluid
Newborn Resultant Problems
- Prone to dehydration
- Prone to acidosis
- Prone to over hydration/ fluid overload
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Description
Explore the essential adaptations newborns undergo in extra-uterine life, focusing on respiration initiation and the factors influencing it. This quiz covers important aspects of newborn management, including circulation and tactile stimulation techniques. Test your understanding of how these physiological changes are vital for newborn survival.
