Page 583 - Clinical Application of Mechanical Ventilation

Neonatal Mechanical Ventilation 549

New surfactants were developed that included the additional lipids and proteins.
Surfactant is given by Delivery was changed from nebulization to direct instillation of surfactant into
direct instillation into the
trachea. the trachea at higher dosages than had previously been used. These discoveries had
dramatic effects on the surfactant-deficient premature lung, with rapid weaning of
pressures and F O levels.
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Indications

There are two protocols for the administration of surfactant, prophylactic and ther-
Prophylactic use of apeutic (“rescue”). Prophylactic use of surfactant is indicated for infants who are at
surfactant is indicated for
infants who are at high risk of high risk of developing RDS because of the short gestation and low body weight.
RDS, ,26-week gestation, However, routine treatment of infants at risk based on these two criteria may un-
PaO 2 /P A O 2 ,0.22, or birth
weight ,1,250 g. necessarily commit some infants to the complications of intubation, mechanical
ventilation, and surfactant administration. At one medical institution, infants born
at or less than 26 weeks gestation and with PaO /P O ,0.22 are treated prophy-
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lactically on a routine basis (British Columbia). Birth weight of less than 1,250 g
may also be an indication for prophylactic use of surfactant (Survanta drug in-
sert). Since protocols vary greatly among institutions, infants with gestational age
or birth weight outside these criteria must be monitored and evaluated for possible
inclusion.
Prophylactic use of surfactant is also given to micropreemies in many neonatal in-
Prophylactic use of tensive care units (NICUs). These infants are usually ,30 weeks and typically weigh
surfactant is also given to
micropreemies (,30 weeks, from 500 g to 1,000 g (1 kg). They are intubated in the delivery room within the
from 500 g to 1,000 g).
first few minutes of birth and given surfactant through the ETT within 15 minutes
of delivery once ETT placement is verified by chest X-ray (Walsh et al., 2010). Pulse
oximeter, oxygen blender, and the use of Neopuff, a device that allows delivery of set
PIP and PEEP, should be considered because of the rapid changes in oxygenation
and compliance. In many cases, rapid weaning of F O to 21% and minimal pres-
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sures for ventilation is possible due to the rapid improvement in compliance. Many
of these premature infants are extubated and transitioned to CPAP or high-flow
devices such as Vapotherm.
Infants eligible for therapeutic (rescue) use of surfactant should fulfill the clinical
Therapeutic (“rescue”) and radiographic criteria for a diagnosis of RDS. The clinical signs may include
use of surfactant is indicated
in RDS (grunting, nasal flar- grunting, nasal flaring, retraction, and cyanosis along with an increasing oxygen or
ing, retraction , cyanosis), ventilatory requirement (i.e., from CPAP to mechanical ventilation). The bilateral
increasing oxygen or ventila-
tory requirement, and positive ground glass appearance on the chest radiograph supports the diagnosis of RDS.
chest radiograph.
Infants who exhibit these clinical and radiographic signs are usually born at ,34
weeks gestation and with an arterial/alveolar (PaO /P O ) ratio of ,0.22 (British
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Columbia). The indications for prophylactic and therapeutic use of surfactant are
summarized in Table 17-3.
Types of Surfactant and Dosages

Currently used surfactants fall into one of two categories: those synthetically pro-
duced or obtained and processed from mammalian lungs. Surfaxin (lucinactant) is a

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