Negative Pressure Aerosol Chamber
Smoke evacuator suction tubing (Stryker Corporation; Product#
0700-026-000; Kalamazoo, MI) was placed under the drape and connected to
a Neptune 3 Waste Management System (Stryker Corporation; Kalamazoo, MI)
to create a negative pressure chamber for the aerosol housing system.
The Neptune 3 Waste Management System is a surgical suction system
designed to provide both hazardous fluid and smoke evacuation during
surgery. It contains both a smoke evacuator filter compartment with an
ultra-low penetrating air (ULPA) efficiency rating and a fluid suction
high-efficiency particulate air (HEPA) filter compartment. The tubing is
connected to the smoke evacuator manifold port on the Neptune suction
system to provide a minimum negative pressure of 0.5 inches of water
gauge. These metrics are consistent with the minimum ventilation
requirements for Class III biological safety cabinets in California. In
addition to the suspension apparatus, we created one or more ventilation
ports, located near head of the bed, to allow airflow into the
negative-pressure chamber. We were not able to measure the pressure
under the drape but did verify the suction was active, and when these
openings for air intake were occluded the drape tended to collapse.
In the first case and NOVID design, a polyethylene film drape (3M Steri
Drape 1010) was supported only by a straight Bookwalter bar.
Unfortunately, the single bar did not provide enough structural support,
and the drape collapsed and occlude the smoke evacuator under vacuum
limiting aerosol clearance. In the final iteration of the negative
pressure housing system, we used the Lone Star ring retractor attached
to a laparoscopic Bookwalter retractor holder to suspend the drape above
the patient’s face without collapse when the negative pressure
environment was created. Gauze was also placed near the tip of the smoke
evacuator to prevent the drape from occluding the smoke evacuator tip
during the surgery.