Improper Connection of Laparoscopic Insufflators and Gas Cylinders
Hazard [Health Devices May 1992;21(5):181-2]
While replacing a CO2 gas cylinder during a laparoscopic
procedure, a member hospital unintentionally connected a cylinder containing a N2/CO2
/He gas mixture, which is intended for use only with laser equipment, to the laparoscopic
insufflator. This improper connection occurred as a result of using two sealing washers
instead of one between the insufflator's yoke and the gas cylinder's valve assembly. The
patient was not injured, even though the error was detected after completing the
procedure. However, introducing a gas or gas mixture that has a low blood solubility and
the ability to support combustion can lead to the formation of a gas embolism or fire,
A CO2 pin-indexed gas cylinder yoke is supplied with most
laparoscopic insufflators to ensure connection to only CO2 gas cylinders.
produce a gastight seal, a single washer is needed when inserting the
insufflator's yoke inlet into the gas cylinder's valve outlet. In the reporting
hospital, all insufflators' yokes and all gas cylinders are equipped with a
washer. In the reported incident, both washers were left in place. Consequently,
when the yoke and valve assembly were connected, the combined width of the two
washers created sufficient space between the pins and pinholes to defeat the
yoke's pin-indexed safety feature, thus allowing virtually any gas cylinder to
be connected (see figure).
We previously reported a similar problem associated with the use of two
washers between an oxygen regulator and a gas cylinder's yoke (see our Hazard Report,
"Oxygen Regulator Fire Caused by Use of Two Yoke Washers," ). Many medical
devices are routinely equipped with a pin-indexed yoke that has a sealing washer, and they
are often used with gas cylinders that also have a sealing washer; therefore, this problem
is not unique to laparoscopic insufflators. Precautions should be taken with any medical
device that uses an external gas source; introducing an improper gas into the body can
place the patient at considerable risk.
Manufacturer action taken
Some manufacturers of laparoscopic insufflators are aware of this problem.
Recently, two of them added a cautionary advisory to their operator's manuals, instructing
customers to use only one washer between the insufflator's yoke and gas cylinder's valve
- Ensure that all hospital personnel who deal with
laparoscopic insufflators are aware of this report.
- Determine whether a sealing washer is present on the yoke inlets of the
insufflators and the valve outlets of the gas cylinders in your hospital.
Implement an appropriate policy (e.g., remove the washers from all of your
hospital's gas cylinders) to ensure that only one washer is used between the
yoke and valve assembly. If not already present, this information should be
appended to the operator's manual of each laparoscopic insufflator. Affix an
appropriate label or tag to the insufflator yoke; for example:
This yoke inlet is equipped with a washer. Remove
washer from gas cylinder's valve outlet, if present.
- Before operating the insufflator, verify that its
yoke is connected to the proper gas cylinder with only one washer between
- Always have a second CO2 gas cylinder available during a laparoscopic procedure to
avoid the possibility of connecting an improper gas tank to the insufflator
when the primary cylinder starts to lose pressure.
- During routine, periodic equipment inspections, verify that a single
washer is being used and that no differences in procedure (e.g., using a new
tank supplier) have occurred that would necessitate a change in
- Insufflators, Laparoscopic [16-849]
- Medical Gas Cylinders [16-501]
Cause of Device-Related Incident
Device factors: Design/labeling error;
Improper maintenance, testing, repair, or lack or failure of incoming inspection
User errors: Failure to perform pre-use inspection; Improper connection
Support system failure: Use of inappropriate devices
Mechanism of Injury or Death
Embolism (gaseous); Fire