Fracture of a GlideScope cobalt blade

syringe and a syringe driver [1]. However, we could not find reports using volumetric infusion pump systems. The Alaris SE pump (CareFusion, Basingstoke, Hampshire, UK) is a linear peristaltic pump, employing a line of moving projections (rather than a rotational peristaltic pump) along with a specific cartridge incorporated into the giving set (AccuSlide Flow Regulator). A peristaltic pump produces accurate one way flow at a wide range of flow rates but, especially in this case, causes an uneven flow over time with the average flow being that inputted by the user. This uneven flow can manifest itself as a pressure wave if transduced. Fig. 2 represents the composite transduced waveform of a patient’s CVP and the peristaltic pump waveform of an Alaris SE volumetric pump set at 50 ml.h. This composite waveform took the instantly recognisable form of an ECG trace of atrial fibrillation (AF) with a rate of 166 and a displayed pressure of 16 cmH2O. The patient’s actual heart rate was 95 beats.min, with a CVP of 14 cmH2O (recorded when the infusion was suspended). When we connected the transducer to an identical set-up using a bag of saline rather than a patient, the waveform was not reproducible, and we saw only an expected deflection with resonance pattern. This suggests it was the combination of the CVP waveform and the waveform produced by the infusion pump that created the AF-like trace. As there are many types of infusion devices employing different propulsion techniques, we recommend regularly isolating the CVP waveform from sources of error in order to obtain accurate readings.