Pediatric emergency medicine trisk 2461 2461
Bạn đang xem bản rút gọn của tài liệu. Xem và tải ngay bản đầy đủ của tài liệu tại đây (99.66 KB, 1 trang )
breathing, the infant will remain well appearing and without signs of respiratory
distress. In contrast, apneic spells last greater than 20 seconds OR are associated
with cyanosis or bradycardia. Apneic events are never a normal finding, and
should be further evaluated (see Chapter 14 Apnea ).
Tachypnea can result from systemic changes, such as fever, hyperthyroidism,
metabolic acidosis, cardiac disease, or pulmonary disease. It is often the only
presenting sign of congestive heart failure. Tachypnea can be a presenting sign
for a number of metabolic disorders, particularly urea cycle defects, as well as
renal disorders, where the body is compensating for metabolic acidosis.
Tachypnea is common with respiratory illnesses, such as bronchiolitis or
pneumonia, but also in premature infants with chronic lung disease, or infants
with a history of congenital pulmonary lesions such as congenital diaphragmatic
hernia. The underlying disease causing tachypnea should be addressed prior to the
development of hypoxia and respiratory failure.
For more details on clinical considerations and management of respiratory rate
anomalies in the neonate, see Section: Neonatal Respiratory and Airway
Problems.
Pulse Oximetry
At sea level, normal pulse oximetry saturation values are greater than 94%; 89%
and higher are acceptable at higher elevations, such as in Denver and Salt Lake
City. Pulse oximetry saturation (POS) values in healthy newborns normalize
within the first few hours of life, with a mean value 97% by 24 hours. POS values
increase incrementally with gestational age, and show variability with infant state.
Crying neonates are more likely to have lower values compared to quiet or
sleeping infants.
Pulse oximetry should be used for any infant with tachypnea, dyspnea, or any
signs of cardiorespiratory illness. Cyanosis may be absent in the face of
significant hypoxemia if the hemoglobin is low (see Section: Color Changes). It
is important to note that acrocyanosis is a common neonatal finding in healthy
infants that can persist for several days to weeks, particularly in cool
environments. This is in contrast to infants with central cyanosis, which should
always be evaluated with pulse oximetry and arterial blood gas measures of
oxygenation.
Hypoxia is never normal in the term newborn, and may be due to respiratory or
cardiac anomalies. Increasingly, pulse oximetry has been used as a screening
method for critical congenital heart diseases (CHDs) that produce hypoxemia.
CHD screening should be completed after 24 hours of life to decrease the
