2002 OPEN FORUM Abstracts
A Ventilator Protocol for Fulminating Non-Cardiogenic Pulmonary Edema
John H. Boynton Jr. RRT, Kenneth Hawkins RRT, Dean Holland, RRT, Jason Higgins, RRT, Grant O'Keefe MD MPH, Parkland Health and Hospital System and UTSWMC, Dallas, Texas
Background: For the purpose of our protocol, the setting and
stabilization of ventilating end pressure during the initial seventy-two
hours post injury is fundamental. The system end pressure is set
and maintained at 2cmH2O above the lower inflection
point as identified on a static pressure-volume curve. Our protocol
is intended to decrease mortality in this high-risk patient population.
Methods: The Oxygenation Index (OI)1 of ten ventilated
surgical/trauma ICU patients (chosen in succession) that present
with fulminating non-cardiogenic pulmonary edema will be compared
with OI value (47) which has been associated with 100% mortality
in ARDS.1 The patients evaluated are as follows: two
patients each with 95% total body surface area (TBSA) burns, one
gastric bypass, one hip replacement, and six with pulmonary contusions.
All patients were in the initial phase of fluid resuscitation or
were immediately post-op. Cardiac origin of the edema was ruled
out in each case via ECG's, Swan-Ganz readings, and clinical presentation.
Results: All patients had OIs > 47. Patient OI's at protocol
initiation ranged from 50-93. Of the ten patients studied, eight
patients survived, one patient (pulmonary contusion) died, and
one patient was not included in the final evaluation secondary
to a breach in protocol.
Experience: In the process of refining
our approach, we discovered three aspects of management, which
were especially important. First, patients must not develop respiratory
efforts for the initial 24-72 hours post onset. Our team used paralytic
agents to prevent patient respiratory effort. Second, frothy secretions
must be removed without compromising system end pressure. We used
short bursts (10-40sec.) of O2 in the range of 25-liters/minute
through an in-line suction catheter advanced to tracheal level
to displace frothy secretions. Third, end pressure should not be
compromised during ventilator disconnects. We successfully maintained
end pressure during disconnects by cross clamping the ETT with
Conclusions: We used OI as a marker in our evaluation because no other commonly used index for oxygenation incorporates the importance of ventilating pressures. Fort et al1 associated OIs greater than 47 with 100% mortality. Although Fort's work was done in a broader population, we believe that OI provides an appropriate index for severity of illness in our population. Our initial experience with this protocol suggests a decrease in mortality. Our findings during this evaluation are consistent with concepts presented in Amato's2 work in electrical impedance tomography. We recognize that this is a limited look at a complicated problem and much more work remains. We will continue to gather data as it becomes available, however, the small number of patients that are included each year make a single center study difficult. A multi-center study of prospective patients may be the best approach.
1. High-frequency oscillatory ventilation for adult respiratory distress syndrome-A pilot study Crit Care Med 1997; 25: 937-947
2. Regional pressure volume curves by electrical impedance tomography in a model of acute lung injury. Crit Care Med. 2000 Jan; 28(1): 178-83.