Design flaw can convert commercially available continuous syringe pumps to intermittent bolus injectors.

OBJECTIVE: To investigate if unexpected behaviour of neonatal and paediatric patients connected to syringe pumps could be explained by transient elevation of these devices. DESIGN: Five different commercially available syringe-pumps were set at an infusion rate of 1 ml/h and then subjected to a vertical displacement manoeuvre (height 1 m). The actual delivered infusion volumes in association with the displacement manoeuvre were measured by a high precision weight scale connected to a computer. SETTING: A medical technology laboratory in a university hospital. MEASUREMENTS AND RESULTS: Elevation of the devices resulted in a rapid bolus injection of 0.19-2.28 ml. Returning the devices to their original positions resulted in an aspiration into the system of 0.06-0.34 ml. The times both for bolus injection and for aspiration into the system were less than 1 min in all cases. The updown manoeuvre was followed by a period with zero infusion ranging from 8 to 105 min. CONCLUSIONS: Design flaws in the construction of syringe pumps can expose patients to substantial danger following vertical displacement if potent drugs are being infused. If potent drugs are infused, care should be taken not to change the vertical position of the syringe pump even for short periods of time. Before buying new equipment, the authors recommend that the delivery characteristics of these devices should not only be tested during ordinary bench testing but should also include the reaction to a vertical displacement manoeuvre.

Meat cooking techniques-Part 1: A preliminary study of the effect of the rate of heating in water.

In an industrial scale experiment forty hams were deboned, trimmed and defatted. The hams were divided into two random groups of twenty, brined and drained and placed into ham moulds. The two groups were heat treated using a high and low rate (0·60°C/min and 0·12°C/min, respectively) of heating in cooking vats. Both groups were, however, heated to identical internal product temperatures defined as the continuous temperature gradient from thermal centre to product periphery (product thermal gradient). After processing and chilling the individual samples were weighed and evaluated by a sensory panel for juiciness and colour. The results show that heating at lower rates in a water bath can increase yield and improve quality, thus indicating that a kinetic effect of heat independent of final product temperature exists. The results thus justify further investigation into the existence and molecular mechanism of this kinetic effect.