Recall that it should be close to 80% as stated earlier) taken. The reason this happens
we discovered is because there is a parallel circuit formed, as soon as a second hand piece
is plugged into the unit. The results immediately raised some concerns about simultaneous
electrocautery. In ANSI/AAMI HF18 1993, 4.4 titled, Accuracy of Performance specifications, section 4.1: b and c. B; states that the output power versus load resistance shall be
within 20% of the stated value, since there is no test procedure in the manufacturers service
manual, we used the above loads which show at 500 ohms the unit delivered roughly 50 %
of the set power at each hand piece, we find this to be out of compliance with the standard.
C; states that the output power versus control setting shall be within 20% of the stated value. We set in 100 watts the unit delivered 50 watts to each hand piece; we found this to be
out of compliance with the standard as well. This led us to realize another situation that we
feel is an area of concern. We are talking about Simultaneous monopolar sub modes that
uses 2 active hand pieces ; however there is only one power setting control and one power
setting indicator. It would only seem natural to have a separate power setting and indicator
for each active hand piece, this way each surgeon would be able to set and control his desired power, and at a glance look at the unit to see what the setting is.
The power shift from hand piece to hand piece
After repeating the test several times, we accidentally stumbled upon another potential
patient safety issue. We notice that if one surgeon was activating his hand piece and the
other surgeon was not, the unit would de liver the set in power 100 watts (+/- 20 %). Now, if
one surgeon was activating his hand piece, and the other surgeon started to activated his
hand piece roughly half of the set in power would immediately shift to the secondary surgeon. This is a significant amount of power, to have 50 watts (50%) of power just shift from
one hand piece to the other hand piece during surgery could render a potential patient safety issue at the activation site.
Test of the Valleylab Force FX