After clamping the umbilical cord, the newborn starts to breathe in?

SCTIMST Staff Nurse - 2015 (Set-B)

Anatomy and Physiology

Easy

Appeared in: SCTIMST Staff Nurse - 2015 (Set-B)

Explanation

The first breath is a reflex triggered by chemical stimuli (hypercapnia, hypoxia) and physical stimuli (cold air, tactile stimulation) after the umbilical cord is clamped.
This process cuts off placental gas exchange, causing CO2 to rise and O2 to fall, which stimulates the respiratory center in the brainstem.
A healthy term newborn is expected to take their first breath almost immediately, with most being vigorous and breathing by 10 to 30 seconds after birth.

Option A: Waiting 5 minutes for a newborn to start breathing would result in severe, irreversible hypoxic brain injury and likely death. This timeframe is far beyond any acceptable limit for neonatal resuscitation.
Option B: A delay of 3 minutes without breathing would cause significant hypoxia and acidosis. The newborn would be in secondary apnea, a life-threatening condition requiring immediate ventilation.
Option D: This marks the end of the 'Golden Minute.' If a newborn has not started breathing effectively by this time, resuscitation with positive-pressure ventilation (PPV) must be initiated. It is a critical action point, not the expected time for the first breath.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Physiology of neonatal transition and initiation of the first breath as background academic context rather than a clinical decision trigger.
Nurses must be prepared for immediate neonatal assessment and resuscitation at every delivery, as the transition to extrauterine life can be unpredictable.
The 'Golden Minute' is a core concept in neonatal care. Rapid assessment and intervention within the first 60 seconds are vital to prevent poor outcomes like hypoxic-ischemic encephalopathy.
What if? If the newborn is apneic and limp at birth (not vigorous), the team should not wait for 30 seconds. They should immediately move the infant to a radiant warmer, begin initial steps (drying, stimulating, positioning the airway), and prepare for PPV, starting it by 60 seconds if there is no response.

How to Approach the Question

This is a clinical timeline question requiring recall of a critical physiological event.
Identify the key event: the initiation of breathing after birth.
Recall the physiology: Cord clamping stops placental gas exchange, creating an urgent need for pulmonary respiration.
Consider the timeframes. In neonatal resuscitation, seconds are critical, while minutes represent significant and potentially dangerous delays.
Eliminate the longer timeframes (1, 3, and 5 minutes) as they are associated with intervention deadlines and risk of injury, not the normal physiological response.
Select the shortest, most immediate timeframe provided, which aligns with the rapid physiological changes occurring at birth.

Concept Tested & Keywords

Concept Tested: Physiology of neonatal transition and initiation of the first breath.
Stem keywords: clamping umbilical cord, newborn, breathe
Lead-in keywords: starts to breathe in

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