Evaluation of the Critikon 8100 and Spacelabs 90207 non-invasive blood pressure monitors using a test simulator

The Critikon Dinamap 8100 and the Spacelabs 90207 ambulatory non-invasive blood pressure (NIBP) monitors were evaluated using a test simulator using an evaluation protocol which covered a wide range of simulated pressures (with five determinations at each of six steps from 60/30 to 200/150 mm Hg), pulse rates (from 40 to 200 bpm), artefact levels (simulated motion and tremor artefact) and pulse strengths (down to 10% of the nominal strength). Determinations were made at 5 min intervals. The average and standard deviation of the five measurements at each condition were calculated. The Spacelabs recorded pressures with a greater consistency than the Dinamap which showed a higher standard deviation under all the conditions. The relatively high standard deviation of the recordings made by the Dinamap could explain the non-systematic errors found in some evaluations. Both instruments recorded pressures within 5 mm Hg of the target over the range of pressures and pulse rates, and coped well under conditions of severe artefact and weak pulsations, either by signalling inability to record or by recording satisfactorily.