Respiratory Problems

Chapter 32 Respiratory Problems



Pathophysiology



Anatomical influences


Neonates are susceptible to respiratory compromise resulting from the following:



image Their stage of lung development and contributing lack of maturation in the other body systems.


image An increased work of breathing owing to the high compliance of the neonatal lung, which results from the cartilaginous nature of the rib structure.


image The neonatal diaphragm being more susceptible to fatigue due to the composition and location of the muscle within the neonatal chest.


image Neonatal airways which are smaller; this generates higher resistance to airflow and a smaller area through which perfusion can occur.


image The tendency for pulmonary blood flow to bypass areas of hypoxia, across the alveolar bed, consequently reducing alveolar perfusion.



Signs of respiratory compromise


These are listed in Box 32.1.



Box 32.1 Signs of respiratory compromise



Grunting




• An audible noise heard on expiration


• Appears when there is the partial closure of the glottis as the breath is expired


• The baby is attempting to preserve some internal lung pressure and prevent the airways from collapsing at the end of the breath



Retractions




• Chest distortions occur due to an increase in the need to create higher inspiratory pressures in a compliant chest


• Appear as intercostal, subcostal or sternal recession across the thorax



Asynchrony




• The breathing appears as a ‘see-saw’ pattern as the abdominal movements and the diaphragm work out of unison


• A result of increased muscle fatigue and the compliant chest wall



Tachypnoea




• This is a compensatory rise in the respiratory rate (above 60 breaths per minute) initiated from the respiratory centre and aims to remove the hypoxia and hypercarbia



Nasal flaring




• An attempt to minimise the effect of the airways’ resistance by maximising the diameter of the upper airways


• The nares are seen to flare open with each breath



Apnoea




• Occurs as the conclusion of increasing respiratory fatigue in the term baby


• The preterm baby may experience apnoea of prematurity due to the immature respiratory centre, as well as apnoea from respiratory fatigue



Common respiratory problems



Pneumothorax


Pneumothoraces are known to occur spontaneously in 1% of the newborn population either during or after birth; however, only one-tenth of this 1% will be symptomatic. The cause at birth is the result of the large pressures generated by the baby’s first breaths. These may range up to 40–80 cm of water. This leads to alveolar distension and rupture, allowing air to leak to a number of sites of which the potential space between the lung pleura is one.


Babies receiving assisted ventilation also have an increased susceptibility to a pneumothorax due to:



image maldistribution of the ventilated gas in the lungs


image high ventilation settings


image infant–ventilator breathing interactions


Presumptive diagnosis:



image reduced breath sounds on the affected side


image displaced heart sounds


image distorted chest/diaphragm movement with respiration


image distension of the chest on the affected side.


Emergency treatment involves either a needle aspiration or the placement of a chest drain.



Transient tachypnoea of the newborn (TTN)


TTN is frequently seen as a diagnosis of exclusion of other possible respiratory causes. The chest X-ray may show a streaky appearance with fluid apparent in the horizontal fissure, confirming the diagnosis and also accounting for the colloquialism of ‘wet lung’.


The most common predisposing factor for TTN is a caesarean section, as the thorax has not been squeezed while the baby descends along the birth canal. This results in lower thoracic pressures after birth. Although these babies require initial care on a neonatal unit, their stay is usually of a short duration with the provision of oxygen and observation.

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Related posts:

  1. The Placenta
  2. Trauma During Birth, Haemorrhage and Convulsions
  3. Obstetric Emergencies
  4. Problems of Pregnancy

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Jul 11, 2016 | Posted by in MIDWIFERY | Comments Off on Respiratory Problems

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