Frequency requirements for zeroing transducers in hemodynamic monitoring.

BACKGROUND

Accurate hemodynamic monitoring information can be obtained only if the transducer/amplifier system is used correctly. One major component of correct use is zeroing the transducer to provide a relative reference point on which to measure hemodynamic pressures. However, nursing requirements for frequency of zeroing are inconsistent. In addition, the concepts of leveling and zeroing are frequently confused.

OBJECTIVE

To determine whether transducers drift from zero (+/- 2 mm Hg), and if they do not drift from zero, how long they hold a zero value.

METHODS

The study, conducted in four midwestern hospitals, was carried out in two parts: an initial 10-day bench test of 50 transducers and an evaluation of 388 transducers attached to patients for 1 to 5 days. Transducers were monitored over time after being consistently leveled.

RESULTS

Bench testing indicated that 100% of transducers did not drift +/- 2 mm Hg from zero during the study period. In the clinical study, only 1.3% of transducers drifted from zero. Five transducers drifted +/- 2 mm Hg from zero, with a range of -5 to 3 mm Hg.

CONCLUSIONS

We conclude that transducers used for hemodynamic monitoring require zeroing only on initial setup and disconnection from the amplifier.