Page 713 - Clinical Application of Mechanical Ventilation

Case Studies 679

dyspnea in addition to orthopnea. She was placed on a monitor that revealed these
Paroxysmal nocturnal vital signs: blood pressure of 160/80 mm Hg, heart rate of 128/min, respiratory
dyspnea and orthopnea are
signs of congestive heart frequency of 28/min and labored, and SpO of 85% on room air.
2
failure.
Further assessment showed 11 to 21 pedal edema, jugular vein distension,
bibasilar crackles, and wheezes throughout.
Arterial blood gases on room air revealed:
pH 7.26
Blood gases show acute PaCO 2 88 mm Hg
ventilatory failure superim- PaO 38 mm Hg
posed on chronic ventilatory 2
-
failure. Noninvasive positive HCO 38 mEq/L
3
pressure ventilation is indi- SaO 80%
cated for this patient. 2
Pertinent lab work results were as follows:
3
3
WBC: 7.4 3 10 (normal 3.2 to 9.8 3 10 )
H&H: 16 Gm %/49.3% (normal for women: hemoglobin 12 to 16 g/100 mL
hematocrit 37 to 47%)
+
Na : 119 (normal 140 mEq/L)
Initial Settings

The patient was stabilized in the emergency department prior to transfer to the
telemetry unit. For her severe hypercapnia and hypoxemia, she was placed on nasal
IPAP provides mechanical bilevel PAP at 12/6 cm H O with 5 L/min of oxygen. IPAP of 12 cm H O was
ventilation and reduces the 2 2
patient’s work of breathing. used to augment the patient’s ventilatory effort. EPAP of 6 cm H O and 5 L/min
2
of oxygen were used to maintain oxygenation and minimize auto-PEEP due to air
trapping.
EPAP improves oxygen-
ation and minimizes auto- Patient Management
PEEP due to air trapping.

For the excessive fluid buildup due to cor pulmonale, 60 mg of Lasix were given
via an intravenous line. Blood was drawn for lab workup. A chest radiograph
and repeat ABG on bilevel PAP were done. Lab reports showed normal WBC,
IPAP of 12 cm H 2 O is
primarily responsible for the hemoglobin, and hematocrit, and low sodium, which could explain some of her
improvement of ventilation
(PaCO 2 from 88 to 68 mm Hg). confusion. The chest radiograph showed enlarged heart (cardiomegaly) with
pulmonary vascular congestion and bilateral infiltrates especially on the left side.
(See Figure 19-7.)
Repeat ABG 2 hours after initiation of bilevel PAP showed:

pH 7.34
PaCO 2 68 mm Hg
PaO 82 mm Hg
EPAP of 6 cm H 2 O and 2 -
5 L/min of oxygen is primarily HCO 36 mEq/L
3
responsible for the improve- SaO 96%
ment of oxygenation (Pao 2 2
from 38 to 82 mm Hg). Bilevel PAP 12/6 cm H O
2
F O 2 5 L/min (nasal bilevel PAP)
I

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