Newborn Adjustments and Respiration

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

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.