Preoperative assessment


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CNS, central nervous system; FO, foramen ovale; G/A, general anesthesia; PDA, patent ductus arteriosus; RPO, retinopathy of prematurity; V./Q., ventilation/perfusion.





5. System review and examination
a) When performing a physical assessment, one should look carefully for congenital anomalies. A rule of thumb is that if there is one anomaly present, there are probably more because many occur in clusters, labeled a syndrome.

b) These problems can occur most often in SGA and large-for-gestational-age (LGA) neonates and should be analyzed and understood as listed in the box on pg. 529.

 



Common Metabolic and Structural Problems in Small- and Large-for-Gestational-Age Infants



Small for gestational age



• Congenital anomalies

• Chromosomal abnormalities

• Chronic intrauterine infection

• Heat loss

• Asphyxia

• Metabolic abnormalities (hypoglycemia, hypocalcemia)

• Polycythemia or hyperbilirubinemia


Large for gestational age



• Birth injury (brachial, phrenic nerve, fractured clavicle)

• Asphyxia

• Meconium aspiration

• Metabolic abnormalities (hypoglycemia, hypocalcemia)

• Polycythemia/hyperbilirubinemia

From Motoyama EK, Davis PJ, eds. Smith’s anesthesia for infants and children. Philadelphia: Mosby; 2006:524.



6. Head and neck abnormalities
a) Any abnormality of the head or neck should raise concerns regarding airway management. The shape and size of the head, with or without the presence of pathology, can make airway management difficult. A small mouth and large tongue can obstruct the airway during mask ventilation.

b) Neonates have very small nares, and when obstructed by an anesthesia face mask, they do not convert to mouth breathing, particularly if the mouth is being held closed.

c) A nasogastric tube can obstruct half of the neonate’s airway and should be placed orally. A small or receding chin, as seen in Pierre Robin and Treacher Collins syndromes, may make direct laryngoscopy and visualization of the glottis impossible, requiring other types of airway management.

d) Cleft lip, with or without cleft palate, may complicate intubation. Anomalies such as cystic hygroma or hemangioma of the neck can produce upper airway obstruction. In the case of a preterm neonate, it should also be determined if the patient has retinopathy of prematurity (ROP), cataracts, or glaucoma.

e) Atropine administration could result in significant increases in intraocular pressure and further damage to the eye.

7. Respiratory system abnormalities
a) Surfactant, which inhibits alveolar collapse, peaks between 35 and 36 of gestational age. Premature neonates are at dramatically increased risk for respiratory failure.

b) The incidence of respiratory distress syndrome (RDS) and bronchopulmonary dysplasia (BPD) is inversely related to gestational age at birth.

c) The onset of RDS can be as early as 6 hours after birth; symptoms include tachypnea, retractions, grunting, and oxygen desaturation.

d) Bronchopulmonary dysplasia is a disease of newborns that manifests as a need for supplemental oxygen along with lower airway obstruction and air trapping, carbon dioxide retention, atelectasis, bronchiolitis, and bronchopneumonia.

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Dec 2, 2016 | Posted by in ANESTHESIA | Comments Off on Preoperative assessment

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