From the June 12, 2003 issue
A hospitalized patient who was connected to a portable
blood pressure (BP) monitoring device was transported to radiology
for an MRI. A length of tubing that led from the monitor's
BP cuff inflator had a male Luer connector. This fit into
a female connector on a shorter length of white tubing that
was integrated with a Critikon disposable BP cuff. See Figure
The tubing and cuff were disconnected before the MRI since
the Luer connector on the monitor's tubing was metal. After
the test, a radiology employee reconnected the tubing and
transported the patient back to his room. Upon arrival,
a family member immediately noticed that the tubing from
the monitor was attached incorrectly to a needleless Y-injection
port on the patient's IV line! A nurse was contacted and
she quickly disconnected the tubing. Normally, the device
cycles at preset intervals, inflating the cuff with more
than 500 mL of air at pressures up to 300 mm Hg. If no resistance
is met with an inflated cuff, two additional cycles quickly
occur. Thus, more than 1,500 mL of air might have entered
the patient's vascular system. Fortunately, this did not
happen, as the machine had not yet cycled to take a BP reading.
Another patient was not as lucky. In that case, the patient
died from an air embolism after a nurse mistakenly connected
the monitor tubing to his IV line.
Poor lighting did not contribute to either mistake, but
another reported case (Stone BA. Avoid Luer connectors on
BP cuffs. Anesthesiology 2002; 97:765-766) shows how similar-appearing
tubing could play a role. A nurse accidentally connected
BP monitor tubing to a white needleless IV port. Propofol,
which is white and opaque, had been infusing through the
patient's IV line. Thus, the IV tubing and port with propofol
looked very similar to the white length of tubing and connector
on the BP cuff. See Figure 1. Patient tampering also could
lead to a problem. In one case reported to FDA, an agitated
patient died when he removed the tubing from his BP cuff
and attached it to his IV line. These inadvertent connections
are more likely to occur at the Y-site of needleless IV
tubing since it requires no manipulation of the tubing.
But it is also possible to connect monitor tubing to any
other tubing with a Luer connector.
FDA and manufacturers have been aware for some time that
Luer connections are used sometimes to connect monitors
to disposable BP cuffs, and that patient deaths have occurred
with inadvertent connections to IV systems. Because of the
risk of air embolism, manufacturers previously issued warning
letters (Spacelabs Medical Urgent Product Safety Alert,
October 29, 2001), and many biomedical engineering departments
alerted clinical managers to the problem. Some manufacturers
also provide warning labels for the monitors and tubing.
Others plan to require dedicated tubing with non-Luer connectors.
However, as long as disposable BP cuffs are available with
female Luer connectors, tubing from the monitor can be inadvertently
connected to an IV.
Although it might be a rare occurrence, this hazard exists
at many hospitals. Indeed, newer monitors may have a proprietary
non-Luer connection at the monitor end, but either the proprietary
connector or a Luer connector can be used with the BP cuff.
Some hospitals that have monitors from different manufacturers
may use cuffs with Luer connectors and replace proprietary
monitor tubing to make all connections compatible. Just
last week, a hospital provided ISMP with BP monitor tubing
with a male Luer connector, and a disposable cuff with a
female Luer connector, both without warning labels. In follow-up
with several other hospitals, we also learned that most
clinical staff were unaware of the problem, even though
their patients were exposed to this hazard.
ISMP has contacted FDA's Center for Devices and Radiological
Health, ECRI, and several manufacturers. All agree that
requiring non-Luer connections will best solve this problem.
Until this becomes a standard, develop a plan to replace
all BP monitoring equipment to ensure incompatibility with
Luer connections. Meanwhile, to protect patients, place
BP cuffs on a different arm than the IV site, and remove
IV catheters as soon as they are no longer needed. Labels
on equipment and staff awareness may be helpful, but unlikely
to have a sustained effect.