2003 OPEN FORUM Abstracts
RELIABILITY OF OXYGENATION INDICES AFTER OPEN HEART SURGERIES
Mohamad El-Khatib, PhD, RRT, Department of Anesthesiology - American
University of Beirut, Lebanon and Robert Chatburn, RRT-NPS, FAARC,
University Hospitals of Cleveland, OH
Background: Various oxygenation indices have been proposed in the literature as
substitutes for a true shunt measurement. These indices do not contain
information related to the level of mechanical ventilation, so may not be as
accurate as possible in some patients. The purpose of this study was to assess the
reliability of two new indices compared to traditional oxygenation measurements
in reflecting the intrapulmonary shunt for patients being ventilated after cardiac
surgery.
Methods: A convenience sample was taken of patients in a university
hospital who were being ventilated after coronary artery bypass grafting.
Simultaneous blood samples were collected from an indwelling arterial line and
a
Swan-Ganz catheter for determination of blood gases. Each index was compared
to the standard shunt index 
using
the Pearson Product Moment Correlation Coefficient. Significance was set at p
= 0.05.
Results: Fifty-five
patients were studied. Shunt values ranged from 1% to 20%. All correlations were
significantly different from zero. Data in the table below are given as mean ±
standard deviation:
Conclusion: In this group of patients, both of the new oxygenation indices,
and 
were
more reliable than other oxygenation measurements in reflecting intrapulmonary
shunt. Inclusion
of
ventilator related information (mean airway pressure and ) may be
responsible for the greater accuracy.
2 CO Pa
