Page 687 - Clinical Application of Mechanical Ventilation

Case Studies 653

(HFO) is an important ventilator strategy when considering adjuncts for refractory
hypoxemia and has been used with success at some facilities. (See references at the
end of this case.)
In an attempt to decrease the pressures exerted within the thorax, the patient was
Pressure-controlled ven- placed on pressure-controlled ventilation with an inverse ratio of 2:1 at pressure of
tilation limits the inspiratory 30 cm H O, T of 0.84 sec, F O of 60%, and PEEP of 10 cm H O. Blood gases
pressure during mechanical 2 I I 2 2
ventilation. taken at the time revealed:
pH 7.43
PaCO 2 47 mm Hg
PaO 2 60 mm Hg
-
HCO 30 mEq/L
3
Hb 11.1 g %
SpO 2 90%
Mode PC-IRV
T I 0.84 sec
I:E ratio 2:1
f 14
PIP 30 cm H O
2
F O 2 60%
I
PEEP 10 cm H O
2
The pressures were then titrated in an effort to improve oxygenation and normal-
The tidal volume deliv-
ered by pressure-controlled ize her condition, but without success.
ventilation is directly related
to the inspiratory pressure.
Key Medications

The patient was placed in a Rotorest® bed to help prevent the development of depen-
dent atelectasis. She was also heavily sedated and maintained in a medicated coma
for over 30 days but without significant improvement. She was given medication
nebulizers with Proventil® every 4 hours for wheezing, lavaged with a combination
of 2.0 mL normal saline (NS), 0.5 mL of 0.5% Proventil®, and 4.0 mL of 10%
Mucomyst® solution, and suctioned prn with her treatment, to improve broncho-
pulmonary hygiene.
Mucomyst and Pulmo-
zyme are used to mobilize By this time she had a large amount of thick, yellow secretions. Dornase alpha
thick, retained secretions. (Pulmozyme®) (0.5 mL) and NS were administered via a small-volume nebulizer to
loosen and remove the retained secretions.

Weaning

The deteriorating hemodynamic status prevented continuing use of inverse I:E ratio
ventilation. She was returned to conventional ventilation throughout the remainder
of her hospitalization. This included ventilation in the assist/control mode at a fre-
quency of 24/min. The patient initiated inspiratory effort to 28/min. She was set to
a V of 500 mL (approx. 9 mL/Kg), F O of 80%, and PEEP of 8 cm H O. Arterial
I
2
2
T
blood gases on these settings produced these results:

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