Page 445 - Clinical Application of Mechanical Ventilation

Management of Mechanical Ventilation 411

Conventional Ventilation Ventilation Plus TGI

Courtesy of Valley Inspired Products, Burnsville, MN. Used with permission.

A B
Figure 12-8 Conventional ventilation and tracheal gas insufflation. (A) In conventional ventila-
tion, expired gas (~4% CO 2 ) remains in the endotracheal tube and goes back into the lung on the
next breath. (B) With tracheal gas insufflation, the expired gas is flushed from the endotracheal tube
with fresh gas (0% CO 2 ). This fresh gas goes into the lungs on the next breath.

the expiratory phase. This phasic timing helps to flush out the ET tube with fresh
gas (0% carbon dioxide) during expiration and fills the ET tube with fresh gas for
the next inspiration (Figure 12-8).
Potential Uses. During mechanical ventilation of newborns, TGI reduces the instrumen-
TGI reduces the instru-
mental deadspace, improves tal deadspace, improves carbon dioxide clearance, reduces carbon dioxide rebreathing,
carbon dioxide clearance, and lowers the ventilation pressure and tidal volume requirements. The PaCO may
and lowers the ventilation 2
pressure and tidal volume be reduced with no change in minute ventilation, or the PaCO may be maintained
2
requirements. at the same level with 10% to 20% reduction in minute ventilation. These effects of
TGI have the potential to decrease the likelihood of secondary lung injury and chronic
lung disease in newborns (Davies et al., 2002; Epstein, 2002; Kalous et al., 2003; Liu
et al., 2004; Virag, 2011). TGI has also been used successfully to reduce the respiratory
demand during weaning from mechanical ventilation (Hoffman et al., 2003).
TGI is a modality that has the potential to improve the management of patients
with acute respiratory failure. Lack of a simple and reliable patient interface for
TGI is one of the problems in the approval process by the FDA (Virag, 2011).
Additional research studies and more clinical trials are necessary to make TGI an
FDA-approved device for the general patient population.

SUMMARY

This chapter outlines the essential strategies that are useful in the management of com-
mon ventilator-related issues. These strategies are straightforward and can be followed
by using a logical deduction process. Careful observation of the patient and ventila-
tor must be done in order to identify the problem. Once the problem is identified,
appropriate steps may be taken. It is vital to remember that no changes to the ventilator
settings should be made unless the reasons for doing so are justifiable based on clini-
cal data and patient presentations.

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