Fluke Biomedical IDA-4 Plus - Manual (Page 64)

IDA-4 Plus
Operators Manual
A-4
Infusion Pumps
General
Common to all pumps is the ability to overcome resistance to flow by increased deliver
pressure. Pumps do not rely on gravity and can therefore be placed in almost any
reasonable position relative to the infusion site (but not too high). The delivery pressure
may rise to high values in some devices in the event of a catheter becoming occluded or
displaced, with the danger of extra-vascular infusion. However, the default pressure is
usually limited in modern pumps and some include a facility for setting very low occlusion
alarm pressures.
Generally Speaking, the performance of pumps is predictable and the volume to be infused
(VTBI) can be set in the confident knowledge that it will be delivered. Associated with this
must come the understanding that these are electrically powered devices, having a number
of risks. They must be used with full knowledge of these risks and thorough training in
their operation.
Pumps are capable of accurate delivery of solution over a wider range of flow rates than
controllers, at both the low and high ends of the delivery range, and may be designed for
specialist applications, to which they must then be restricted.
Drip - Rate Pumps
The flow rate is selected in drops per minute and this alone allows users to distinguish
them from volumetric pumps. A drop sensor attached to the drip chamber counts drops and
the pump then infuses the set drip rate into the patient.
Pumping is achieved either by the peristaltic action of rollers or, usually, by mechanical
fingers (linear peristaltic) on deformable tubing. This latter type of pump uses a standard
administration set, but rotary peristaltic pumps generally require softer tubing and special
sets are provided with a pumping insert made of suitable material. Pumps that use drop
sensing as their means of control do not normally compensate for variation in drop size.
Controls are few and simple, with only rudimentary alarms to warn of any departure from
the set rate and some other malfunctions.
Air - in - line detection is rarely, if ever, provided and the occlusion response is poor, with
high pressures being reached. These pressures are so high that in practice the alarm would
probably never activate during extra - vascular infusion.
Volumetric Pumps
These are the preferred pumps for medium and large flow rate and large volume infusions;
although some are designed specially to operate at low flow rates for neonatal use. All are
mains / battery powered, with rate being selected in milliliters per hour. Most use a linear
peristaltic pumping mechanism, but other mechanisms are available, such as cassettes.
Volumetric pumps usually incorporate a wide range of features, required for neonatal and
high-risk infusions, including air-in-line detector and comprehensive alarms. These
features, if properly used, make intravenous (IV) infusion much safer. There are, however,
some models either having, or which can be configured to have, a more basic specification,
making them suitable for lower risk infusions only.
Some volumetric pumps incorporate a drop sensor, but only for monitoring and alarm
purposes (such as empty container) and not as a primary control of delivery rate. Some are
designed to be used with standard PVC gravity administration sets.
In common with all pumps, they have the capability of developing high delivery pressures
(but not as high as drip-rate pumps) and due regard must be paid to this. However, in most
pumps of this type, the pressure is limited to a pre-set value above which the pump will
alarm.
Volumetric pumps generally incorporate the following features: