2006 OPEN FORUM Abstracts
HUMIDIFICATION AND AEROSOL DELIVERY DURING MECHANICAL VENTILATION USING CAPILLARY FORCE VAPORIZATION (C-FORCET)
M.
Solomita, D.O. 1 and G.C.
Smaldone, M.D.,PhD 1
1.Department
of Pulmonary and Critical Care Medicine, SUNY at Stony Brook, Stony Brook, NY
11794
Background: To compare a device using capillary
force vaporization (C-ForceT ; Pari Respiratory Equipment, Midlothian, VA) to
conventional humidification systems during mechanical ventilation.
Methods: The C-ForceT was integrated
into a modified ventilator circuit to measure water vapor delivery. The device
consists of a water pump and a heater plate designed to sit at the Y-piece. The
heater plate was set at 130 °C. The water
pump rate was adjusted to achieve a Y-piece temperature of 35 °C, as measured by a thermocouple
from a conventional humidification system. A condenser tube was used to
condense and measure some of the water vapor generated. Hygrometric
measurements were made and used to determine the absolute humidity (AH) of the
gas which escaped the condenser. Using the AH, the amount of water vapor which
escaped the condenser was calculated. This allowed us to determine the amount
of water delivered. The same was done for a non-heated wire (NHWH) and heated
wire humidifier (HWH). In addition, we
measured the amount of water each device consumed from its water reservoir in
order to determine device efficiency (water delivered / water
consumed). Experiments
were performed using three different ventilators (Drager 4 NeoFlow, Puritan
Bennett 7200, T-Bird AVS III) and two different breathing patterns (TV=750,
RR=15 and TV=400, RR=15). Aerosol delivery was determined by nebulizing
radiolabeled albuterol with an Aerotech II nebulizer. Each humidification device was evaluated with
the PB7200 (breath actuated nebulization, TV=750, RR=15). An inhaled mass (IM) filter was placed at the
end of the ETT to determine the percentage of radioactivity, and therefore
aerosol, that would be delivered to a patient.
Results: C-ForceT
delivered 15.0 ± 2.0, 15.7 ± 0.8, and 8.7 ± 0.5 mL water/hr at TV=400, and 30.7
± 0.3, 28.9 ± 1.0, and 16.9 ± 1.2 mL water/hr at TV=750 using the Drager,
PB7200, and T-bird ventilators respectively. The NHWH delivered 13.5 ± 0.3,
14.0 ± 0.8, and 13.6 ± 0.3 mL water/hr at TV=400, and 27.5 ± 0.6, 28.5 ± 0.5,
and 23.3 ± 0.5 mL water/hr at TV=750 using the Drager, PB7200, and T-bird
ventilators respectively. The HWH delivered 13.6 ± 0.8, 12.2 ± 0.5, and 10.9 ±
1.2 mL water/hr at TV=400, and 21.4 ± 1.2, 24.2 ± 1.0, and 18.1 ± 0.3 mL
water/hr at TV=750 using the Drager, PB7200, and T-bird ventilators
respectively. HWH and C- ForceT
were more efficient than NHWH (HWH 67.8, 49.2, NHWH 36.7, 18.8, and CFV 66.4,
53.7% at TV=750 and TV=400 respectively). Efficiency was reduced when using the
T-bird ventilator with each device. IM was 9.5 ± 1.6, 13.7 ± 0.9, and
16.0 ± 1.2 % for the NHWH, HWH, and C-
ForceT respectively.
Conclusions: C-forceT
is an effective method for humidifying a ventilator circuit. It eliminates inspiratory line condensation,
uses sterile water efficiently, and has greater aerosol delivery during device
use when compared to conventional systems. Humidification device performance is
reduced due to bias flow (T-bird ventilator).