Chapter 15: Medicines optimization: ensuring quality and safety
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Source: Reproduced with permission of the Medical Devices Agency. © Crown copyright. Reproduced under the Open Government Licence v2.0.
Source: Reproduced from Quinn ([293]) with permission of John Wiley & Sons.
Source: Reproduced from Quinn ([293]) with permission of John Wiley & Sons.
Source: Adapted from Department of Health (Northern Ireland) ([57]), Health Care Standards Unit ([123], [124]), MHRA ([208]), Quinn ([292]).
Source: MHRA ([208]). © Crown copyright. Reproduced under the Open Government Licence v2.0.
Intravenous injections and infusions
Definition
Intravenous injections and infusions involve the introduction of medication or solutions into the circulatory system via a peripheral or central vein (Chernecky et al. [39]).
Anatomy and physiology
See Chapter c17: Vascular access devices: insertion and management for anatomy and physiology related to the venous system.
Related theory
Intravenous therapy is now an integral part of the majority of nurses’ professional practice (RCN [295]). The nurse's role has progressed considerably from being able to add drugs to infusion bags (DHSS [68]) to now assessing patients and inserting the appropriate vascular access device (VAD) prior to drug administration (Gabriel et al. [102]).
Any nurse administering intravenous drugs must be competent in all aspects of intravenous therapy and act in accordance with The Code (NMC [257]) – that is, they must maintain their knowledge and skills (Hyde [138], RCN [295]). Training and assessment should comprise both theoretical and practical components and include legal and professional issues, fluid balance, pharmacology, drug administration, local and systemic complications, infection control issues, use of equipment and risk management (Hyde [138], RCN [295]).
The nurse's responsibilities in relation to intravenous drug administration include the following:
- knowing the therapeutic use of the drug or solution as well as its normal dosage, side‐effects, precautions and contraindications
- preparing the drug aseptically and safely, checking the container and drug for faults, using the correct diluent and only preparing the drug immediately prior to administration
- identifying the patient and checking their allergy status
- checking the prescription chart
- checking and maintaining the patency of the VAD
- inspecting the site of the VAD and managing or reporting complications where appropriate
- controlling the flow rate of the infusion and/or the speed of the injection
- monitoring the condition of the patient and reporting changes
- clearly and immediately making records of all drugs administered (Finlay [94], RCN [295], RPS [317]).
Evidence‐based approaches
Methods of administering intravenous drugs
There are three methods of administering intravenous drugs: continuous infusion, intermittent infusion and direct intermittent injection.
Continuous infusion
Continuous infusion may be defined as the intravenous delivery of a medication or fluid at a constant rate over a prescribed time period, ranging from several hours to several days, to achieve a controlled therapeutic response (Turner and Hankins [355]). The greater dilution also helps to reduce venous irritation (Weinstein and Hagle [363], Whittington [368]).
A continuous infusion may be used when:
- the drugs to be administered must be highly diluted
- maintenance of steady blood levels of the drug is required (Turner and Hankins [355]).
Pre‐prepared infusion fluids with additives (such as potassium chloride) should be used whenever possible. This reduces the risk of extrinsic contamination, which can occur during the mixing of drugs (Weinstein and Hagle [363]). Only one addition should be made to each bottle or bag of fluid after the compatibility has been ascertained. More additions can increase the risk of incompatibility occurring, for example precipitation (Weinstein and Hagle [363], Whittington [368]). The additive and fluid must be mixed well to prevent a layering effect, which can occur with some drugs (Whittington [368]). The danger is that a bolus injection of the drug may be delivered. To safeguard against this, any additions should be made to the infusion fluid and the container inverted a number of times to ensure mixing of the drug, before the fluid is hung on the infusion stand (NPSA [268]). The infusion container should be labelled clearly after the addition has been made. The infusion fluid mixture should constantly be monitored for cloudiness or the presence of particles (Weinstein and Hagle [363], Whittington [368]), and the patient's condition and the intravenous site should be checked for patency, extravasation or infiltration (Downie et al. [82]).
Intermittent infusion
Intermittent infusion is the administration of a small‐volume infusion (25–250 mL) over a period of between 15 minutes and 2 hours (Turner and Hankins [355]). This may be given as a specific dose at one time or at repeated intervals during 24 hours (Pickstone [284]).
An intermittent infusion may be used when:
- a peak plasma level is required therapeutically
- the pharmacology of the drug dictates this specific dilution
- the drug will not remain stable for the time required to administer a more dilute volume
- the patient is on a restricted intake of fluids (Whittington [368]).
Delivery of the drug by intermittent infusion can be piggy‐backed (via a needle‐free injection port) if the primary infusion is of a compatible fluid, using a system such as a ‘Y’ set or a burette set with a chamber capacity of 100 or 150 mL (Turner and Hankins [355]). This technique involves adding the drug to the burette and infusing it while the primary infusion is switched off. A small‐volume infusion may also be connected to a cannula specifically to keep the vein open and maintain patency.
All of the points to be considered when preparing for a continuous infusion should be taken into account here, for example pre‐preparing fluids, only adding one drug, and adequate mixing, labelling and monitoring.
After completion of an intermittent infusion, an appropriate diluent solution should be administered via the administration set. This is to ensure the full dose of medication has been administered to the patient.
The National Infusion and Vascular Access Society has published guidance on appropriate line flushing after infusion. This was prompted by concerns about the theoretical risk of under‐dosing in intravenous infusions, when some of the drug is left in the tubing of the giving set at the end of the administration (NIVAS [256]). As this guidance is new and under regular review, it is advised that it be accessed online for the most up‐to‐date advice (https://nivas.org.uk). All organizations should ensure that their policies and procedures reflect the current guidance.
Direct intermittent injection
Direct intermittent injection (also known as intravenous push or bolus) involves the injection of a drug from a syringe into the injection port of an administration set or directly into a VAD (Dougherty and Lamb [80], Turner and Hankins [355]). Most are administered over a time span of anywhere from 3 to 10 minutes depending upon the drug (Weinstein and Hagle [363], Whittington [368]).
A direct injection may be used when:
- the vital organs require the maximum concentration of the drug – this is a ‘bolus’ injection, which is given rapidly over seconds, often in an emergency (e.g. adrenaline)
- the drug cannot be further diluted for pharmacological or therapeutic reasons or does not require dilution – this is given as a controlled ‘push’ injection over a few minutes
- a peak blood level is required and cannot be achieved by small‐volume infusion (Turner and Hankins [355]).
Rapid administration can result in toxic levels and an anaphylactic‐type reaction. Manufacturers’ recommendations on rates of administration (i.e. millilitres or milligrams per minute) should be adhered to. In the absence of such recommendations, administration should proceed slowly, over 5–10 minutes (Dougherty [75]).
Delivery of a drug by direct injection may be achieved via a cannula through a resealable needleless injection cap, an extension set or the injection site of an administration set. If a peripheral device is in situ, the bandage and dressing must be removed to inspect the insertion of the cannula, unless a transparent dressing is in place (Finlay [94]). Patency of the vein must be confirmed prior to administration and the vein's ability to accept an extra flow of fluid or irritant chemical must also be checked (Dougherty [77]).
Administration into the injection site of a fast‐running drip may be advised if the infusion in progress is compatible, in order to dilute the drug further and reduce local chemical irritation (Dougherty [75]). Alternatively, a stop–start procedure may be employed if there is doubt about venous patency. This allows the nurse to constantly check the patency of the vein and detect early signs of extravasation. If the infusion fluid is incompatible with the drug, the administration set may be switched off and a compatible solution may be used as a flush (NPSA [268]).
If a number of drugs are being administered, 0.9% sodium chloride must be used to flush the device between each drug to prevent interactions. In addition, 0.9% sodium chloride should be used at the end of the administration to ensure that all of the drug has been delivered. The device should then be flushed to ensure patency is maintained (see Chapter c17: Vascular access devices: insertion and management) (Dougherty [77]).
Principles to be followed when administering intravenous drugs
The following principles should be applied throughout preparation and administration of intravenous drugs.
Asepsis and reducing the risk of infection
Microbes on the hands of healthcare personnel contribute to healthcare‐associated infection (Weinstein and Hagle [363]). Therefore, aseptic technique must be adhered to throughout all intravenous procedures (see Chapter c17: Vascular access devices: insertion and management). The nurse must employ good hand washing and drying techniques using a bactericidal soap or an alcohol‐based handrub. If asepsis is not maintained, local infection, septic phlebitis or septicaemia may result (Hart [120], Loveday et al. [176], RCN [295]).
The insertion site should be inspected at least once per day for complications such as infiltration, phlebitis or any indication of infection, for example redness at the insertion site or pyrexia (RCN [295]). These problems may necessitate the removal of the device and/or further investigation (Finlay [94]).
It is desirable that a closed system of infusion is maintained wherever possible, with as few connections as are necessary (Finlay [94], Hart [120]). This reduces the risk of bacterial contamination. Any extra connections within the administration system increase the risk of infection. Three‐way taps have been shown to encourage the growth of micro‐organisms. They are difficult to clean due to their design, as micro‐organisms can become lodged and are then able to multiply in the warm, moist environment (Finlay [94], Hart [120]). This reservoir of micro‐organisms may then be released into the patient's circulation.
The injection sites on administration sets or injection caps should be cleaned using a 2% chlorhexidine alcohol‐based antiseptic, allowing time for it to dry (Loveday et al. [176]). Connections should be cleaned before changing administration sets and manipulations kept to a minimum. Administration sets should be changed according to use (intermittent or continuous therapy), type of device and type of solution, and the set must be labelled with the date and time of the change (NPSA [268], RCN [295]).
To ensure safe delivery of intravenous fluids and medication:
- Replace all tubing when the VAD is replaced (Loveday et al. [176]).
- Replace solution administration sets and stopcocks used for continuous infusions every 96 hours unless clinically indicated, for example if drug stability data indicate otherwise (Loveday et al. [176], RCN [295]). A Cochrane review of 13 randomized controlled trials found no evidence that changing intravenous administration sets more often than every 96 hours reduces the incidence of bloodstream infection (Loveday et al. [176]).
- Replace solution administration sets used for lipid emulsions and parenteral nutrition at the end of the infusion or within 24 hours of initiating the infusion (Loveday et al. [176], RCN [295]).
- Replace blood administration sets at least every 12 hours and after every second unit of blood (Loveday et al. [176], McClelland [190], RCN [295]).
- All solution sets used for intermittent infusions (e.g. of antibiotics) should be discarded immediately after use and not be allowed to hang for reuse (RCN [295]).
- If administering more than one infusion via a multilumen extension set or multiple ports, be aware of the risk of backtracking of medication and consider using sets with one‐way, non‐return or anti‐reflux valves (MHRA [207]).
Inspection of fluids, drugs, equipment and their packaging must be undertaken to detect any points where contamination may have occurred during manufacture and/or transport. Such intrinsic contamination may be detected as cloudiness, discoloration or the presence of particles (BNF [25], RCN [295], Weinstein and Hagle [363]). Infusion bags should not be left hanging for longer than 24 hours. In the case of blood and blood products, this limit is reduced to 5 hours (McClelland [190], RCN [295]).
Safety
All details of the prescription and all calculations must be checked carefully in accordance with hospital policy in order to ensure safe preparation and administration of the drug(s). Accurate labelling of additives and records of administration are essential (NPSA [268], RCN [295]).
The nurse must also check the compatibility of the drug with the diluent or infusion fluid. The nurse should be aware of the types of incompatibilities and the factors that could influence them. These include pH, concentration, time, temperature, light and the brand of the drug. If insufficient information is available, a reference book (e.g. the British National Formulary; BNF [25]) or the product data sheet must be consulted (NPSA [268], Whittington [368]). If the nurse is unsure about any aspect of the preparation and/or administration of a drug, they should not proceed and should consult with a senior member of staff (NMC [257]). Constant monitoring of both the mixture and the patient is important. The preferred method and rate of intravenous administration must be determined.
Drugs should never be added to the following:
Only specially prepared additives should be used with fat emulsions or amino acid preparations (Downie et al. [82]).
Any protective clothing that is advised should be worn, and vinyl gloves should be used to reduce the risk of latex allergy (Hart [120]). Healthcare professionals who use gloves frequently or for long periods face a high risk of allergy from latex products. All healthcare facilities should develop policies and procedures that determine measures to protect staff and patients from latex exposure and outline a treatment plan for latex reactions (RCN [295]).
Preventing needle stick injuries should be key in any health and safety programme, and organizations should introduce safety devices and needle‐free systems wherever possible (EASHW [84]). Basic rules of safety include not resheathing needles, disposal of needles into a recognized sharps bin immediately after use, and convenient location of sharps bins in all areas where needles and sharps are used (Hart [120], MHRA [201], RCN [295]).
Comfort
Both the physical and the psychological comfort of the patient must be considered. Comprehensive explanation of the practical aspects of the procedure together with information about the effects of the treatment will contribute to reducing anxiety, although the provision of such information must be tailored to each patient's individual needs.
Clinical governance
At least one patient will experience a potentially serious intravenous drug error every day in an ‘average’ hospital. Intravenous drug errors have been estimated to account for a third of all drug errors. According to the NPSA ([261]), ‘fifteen million infusions are performed in the NHS every year and 700 unsafe incidents are reported each year with 19% attributed to user error’ (p.1). Between 2005 and 2010, the MHRA investigated 1085 reports involving infusion pumps (MHRA [209]). In 69% of incidents, no cause was established. However, of the remaining incidents, 20% were attributed to user error (e.g. misloading the administration set or syringe, setting the wrong rate or confusing the pump type) and 11% to device‐related issues (e.g. poor maintenance or inadequate cleaning) (MHRA [209]). Syringe pumps have given rise to the most significant problems in terms of patient mortality and morbidity (Fox [97], MHRA [208], NPSA [260]).
The high frequency of human error in the intravenous administration of drugs has highlighted the need for more formalized, validated and competency‐based training and assessment (MHRA [208], NPSA [260], [261], Pickstone [285], Quinn [292]). Nurses must be familiar with the device they are using and not attempt to operate any device that they have not been fully trained to use (MHRA [209], Murray and Glenister [222], NPSA [260]). As a minimum, the training should cover the device, relevant drugs and solutions, and the practical procedures related to setting up the device and problem solving (MHRA [208], MHRA [209], [210]). Staff should also be made aware of the mechanisms for reporting faults with devices and procedures for adverse incident reporting within their trust and to the MHRA (MHRA [203], MHRA [209]).
A useful checklist (Box 15.12) has been produced by the Medical Devices Agency for staff to follow prior to using a medical device to ensure safe practice (see also MHRA [208], [210]).
Box 15.12
Checklist: how safe is your practice?
- Have I been trained in the use of the infusion device?
- Was the training formalized and recorded or did I just pick it up as I went along?
- How was my competency in relation to the infusion device assessed?
- Have I read the user instructions on how to use the infusion device and am I familiar with any warning labels?
- When was the infusion device last serviced?
- Are there any signs of wear, damage or faults?
- Do I know how to set up and use the infusion device?
- Is the infusion device and any additional equipment in good working order?
- Do I know how the infusion device should perform and the monitoring that needs to be done to check its performance?
- Am I using the correct additional equipment, for example the appropriate disposable administration set for the infusion pump?
- Do I know how to recognize whether the infusion device has failed?
- Do I know what to do if the infusion device fails?
- Do I know how and to whom to report an infusion device‐related adverse incident?
- Does checking the infusion device indicate it is functioning correctly and to the manufacturer's specification?
- What action should be taken if the infusion device is not functioning properly?
- Is there up‐to‐date documentation to record regular checking of the infusion device?
- What are the details (name and serial number) of the infusion device being used?
- What is the cleaning and/or decontamination procedure for the infusion device and what are my responsibilities in this process?
- Do I know how to report an adverse incident?
- Do I have access to MHRA device bulletins of relevance to my area of practice and do I read and take note of hazard and safety notices?
Nurses must have knowledge of the relevant solutions, their effects, rates of administration, factors that affect the flow of infusions, and the complications that can occur when flow is not controlled (Weinstein and Hagle [363]). They should also have an understanding of which groups require accurate flow control in order to prevent complications (Box 15.13) and how to select the most appropriate device for accuracy of delivery to best meet the patient's flow control needs (according to age, condition, setting and prescribed therapy) (Weinstein and Hagle [363]).
Box 15.13
Groups at risk of complications associated with flow control
- Infants and young children
- The elderly
- Patients with compromised cardiovascular status
- Patients with impairment or failure of organs, for example kidneys
- Patients with major sepsis
- Patients suffering from shock, whatever the cause
- Post‐operative or post‐trauma patients
- Stressed patients, whose endocrine homeostatic controls may be affected
- Patients receiving multiple medications, whose clinical status may change rapidly
The identification of risks is crucial. Risks include the potential for error in complex calculations, prescription errors (Dougherty [75], Weinstein and Hagle [363]), and risks specifically associated with infusions, such as neonatal risk infusions, high‐risk infusions, low‐risk infusions and ambulatory infusions (MHRA [208], Quinn [292]). Early detection of errors and infusion‐related complications, for example overinfusion or underinfusion (Box 15.14), is imperative in order to instigate the appropriate interventions in response to an error or to manage any complications, as serious errors or complications can result in patient death (Dougherty [75], NPSA [260], Quinn [293]). Overinfusion accounts for about half of the reported errors involving infusion pumps, with 80% due to user error rather than a fault with the device (MHRA [210]). The use of infusion devices, both mechanical and electronic, has increased the level of safety of intravenous therapy. However, it is recommended that a clearly defined structure for management of infusion systems should exist within a hospital (Department of Health (Northern Ireland) [57], MHRA [208], [209], NPSA [261]) (Box 15.15).
Box 15.14
Complications of inadequate flow control
Complications associated with overinfusion
- Fluid overload with accompanying electrolyte imbalance
- Metabolic disturbances during parenteral nutrition, mainly related to serum glucose levels
- Toxic concentrations of medications, which may result in a shock‐like syndrome (‘speed shock’)
- Air embolism, due to containers running dry before expected
- An increase in venous complications, for example chemical phlebitis, caused by reduced dilution of irritant substances (Weinstein and Hagle [363])
Complications associated with underinfusion
- Dehydration
- Metabolic disturbances
- A delayed response to medications or below therapeutic dose
- Occlusion of a cannula/catheter due to slow flow or cessation of flow
Box 15.15
Criteria for selection of an infusion device
- Rationalization of devices
- Clinical requirement
- Education
- Compatibility with other equipment
- Disposable components
- Product support
- Costs
- Service and maintenance
- Regulatory issues
Strategies must be developed for the replacement of old, obsolete or inappropriate devices (MHRA [212]). Healthcare professionals are personally accountable for their use of infusion devices and they must therefore ensure they have appropriate training before using any pump (MHRA [212]). Records of training must also be maintained.
Improving infusion device safety
As mentioned, a high frequency of human error is reported in the use of infusion device systems, so competence‐based training is advocated for users of these systems (MHRA [208], NPSA [261]). By rationalizing the range of infusion device types within organizations and establishing a centralized equipment library, the number of patient safety incidents will be reduced (MHRA [208], NPSA [261]). Smart infusion pumps reduce pump programming errors by setting pre‐programmed upper and lower dose limits for specific drugs. The pump will alert the nurse if it has been set outside the pre‐determined dose limits (Keohane et al. [153], MHRA [209], Weinstein and Hagle [363], Wilson and Sullivan [374]). Whatever infusion device is used, the need to monitor the patient and the device remains paramount for patient safety (Quinn [293], RCN [295]).
Pre‐procedural considerations
Equipment
Vascular access devices
For VADs see Chapter c17: Vascular access devices: insertion and management.
Administration sets
An administration set is used to administer fluids, blood or medications via an infusion bag into a VAD. The set comprises a number of components (see Figures 15.30, 15.31 and 15.32). At the top is a spike, which is inserted into the infusion container via an entry port. The spike is covered by a sterile plastic lid, which is removed just prior to insertion into the container (Downie et al. [82]). The plastic tubing continues from the spike to a drip chamber, which may contain a filter. This is filled by squeezing it when the tubing is attached to the fluid and waiting for the chamber to fill half way, thus allowing the practitioner to observe the drops. Along the tubing is a roller clamp, which allows the tubing to be incrementally occluded as the clamp can be tightened to pinch the tubing; this is used to adjust the rate of flow (Hadaway [112]). The clamp is usually positioned on the upper third of the administration set but should be repositioned along the set at intervals as the tubing can develop a ‘memory’ and not regain its shape, making it difficult to regulate (Hadaway [112]). The clamp is opened to allow the fluid along the tubing so as to remove the air, and then closed until the set has been attached to the patient's VAD. Finally, the Luer‐Lok end is covered with a plastic cap to maintain sterility until it is attached (Downie et al. [82]).
Figure 15.30 Fluid administration set.
Figure 15.31 Roller clamp.
Figure 15.32 Labelled administration set.
There is a variety of sets. A solution set is used to administer crystalloid solutions (it can be used as a primary or secondary set and is also available as a Y‐set to allow for dual administration of compatible solutions). Parenteral nutrition is also administered via solution sets. Solution sets may have needle‐free injection ports, which allow for the administration of bolus injections or the connection of secondary infusions. Sets may also have back‐check valves, which allow solutions to flow in one direction only and are especially used when a secondary set is needed (Hadaway [112]).
Blood and blood products are administered via a blood administration set (Figure 15.33), which has a special filter. Platelets can be administered via blood administration sets (check the manufacturer's guidance) or specialist platelet administration sets. Some medications, such as taxanes, must be administered via special taxane administration sets, which have a 0.22 μm filter.
Figure 15.33 Blood administration set.
Extension sets
Extension sets are used to add length (Hadaway [112]). Short (under 50 cm) extension sets tend to have a needle‐free connector (Figure 15.34) and are attached directly to the VAD to provide a closed system; other equipment is then attached via the needle‐free connector. Long (50–200 cm) extension sets are used to connect syringe pumps to a VAD and usually have a back‐check or anti‐siphon valve. They can be single, double or triple and may contain a slide or pinch clamp but do not regulate flow (Hadaway [112]).
Figure 15.34 Extension set with needle‐free injection cap.
Needleless connectors and injection caps
These are caps that are attached to the end of a VAD or extension set (see Figure 15.34) to provide a closed system and remove the need for needles when administering medications, thus removing the risk of needle stick injury. There are various types available, categorized by the internal mechanisms (split septum or mechanical valve) (Hadaway [112]) and how they function (i.e. the presence of fluid displacement inside the device). There are three main types:
- negative: blood is pulled back into the catheter lumen; for example, this occurs when an empty fluid container is left connected, which can lead to occlusion
- positive: these caps have a valve with a reservoir that holds a small amount of fluid; upon disconnection, this fluid is pushed out to the catheter lumen to overcome the reflux of blood that has occurred
- neutral: these caps contain valves that prevent blood reflux upon connection and disconnection (Hadaway [112]).
Others are coated with antimicrobial or antibacterial solutions on their external or internal parts to reduce the risk of infection (Hadaway [112]). These require regular changing in accordance with the manufacturer's instructions as well as cleaning before and after each use (MHRA [204], [206]).
It has been suggested that needle‐free systems can increase the risk of bloodstream infections (Danzig et al. [52]). However, most studies have found no differences in rates of microbial contamination when comparing conventional and needle‐free systems (Brown et al. [33], Luebke et al. [177], Mendelson et al. [198]). It appears that an increased risk is only likely where there is lack of compliance with cleaning protocols or changing of equipment (Loveday et al. [176]).
Other equipment
Other intravenous equipment includes stopcocks (used to direct flow), which are usually three‐ or four‐way devices. These tend to be used in critical care but their use is discouraged in the general setting due to misuse and contamination issues. If used, they should be capped off (Hadaway [112]).
Infusion devices
An infusion device is designed to accurately deliver measured amounts of fluid or drugs via a number of routes (intravenous, subcutaneous or epidural) over a period of time. The infusion device is set at an appropriate rate to achieve the desired therapeutic response and prevent complications (Dougherty [75], MHRA [208], [209]).
Gravity infusion devices
Gravity infusion devices depend entirely on gravity to deliver the infusion. The system consists of an administration set containing a drip chamber and a roller clamp to control the flow, which is usually measured by counting drops (Pickstone [284]). The indications for their use are:
- delivery of fluids without additives
- administration of drugs or fluids where adverse effects are not anticipated and absolute precision is not required
- administration of drugs or fluids where the patient's condition does not give cause for concern and no complication is predicted (Quinn [293]).
The flow rate is calculated using a formula that requires the following information:
- the volume to be infused
- the number of hours the infusion will run for
- the drop rate of the administration set (which will differ depending on type of set).
The number of drops per millilitre is dependent on the type of administration set used and the viscosity of the infusion fluid. Increased viscosity causes the size of the drop to increase. For example, crystalloid fluid administered via a solution set is delivered at the rate of 20 drops/mL, whereas the rate of packed red cells given via a blood set will be calculated at 15 drops/mL (Quinn [293]).
The rate of administration of a continuous or intermittent infusion may be calculated from the following equation (Pickstone [284]):
 |
In this equation, 60 is a factor for the conversion of the number of hours to the number of minutes.
Factors influencing flow rates are as follows.
Type of fluid
The composition, viscosity and concentration of the fluid affect flow (Pickstone [284], Quinn [292], Springhouse [338], Weinstein and Hagle [363]). Irritating solutions may result in venospasm and impede the flow rate, but this may be resolved by the use of a warm pack over the cannula site and the limb (Springhouse [338], Weinstein and Hagle [363]).
Height of the infusion container
Intravenous fluids run by gravity and so any changes in the height of the container will alter the flow rate. The container can be hung up to 1.5 m above the infusion site, which will provide a hydrostatic pressure of 110 mmHg (MHRA [208], Springhouse [338]). One metre above the infusion site would create 70 mmHg of pressure, which is adequate to overcome venous pressure (the normal range in an adult is 25–80 mmHg) (Pickstone [284]). If it is hung too high then it can create too great a pressure within the vein, leading to infiltration of the medication (MHRA [202]). Therefore, any alterations in the patient's position may alter the flow rate and necessitate a change in the speed of the infusion to maintain the appropriate rate of flow (Hadaway [112], MHRA [209], Weinstein and Hagle [363]). Positioning of the patient will affect flow; patients should be instructed to keep the arm that is receiving the infusion lower than the container, if the infusion is reliant on gravity (Quinn [293]).
Administration set
The flow rate of the infusion may be affected in several ways:
- Roller clamps (see Figure 15.31) or screw clamps, used to adjust and maintain rates of flow on gravity infusions, vary considerably in their efficiency and accuracy. This variability is often dependent on a number of factors, such as patient movement and height of the infusion container (Hadaway [112]). The roller clamp should be used as the primary means of occluding the tubing even if there is an anti‐free‐flow device (MHRA [208]).
- The inner diameter of the lumen and the length of tubing will also affect flow. Microbore sets have a narrow lumen, so flow is restricted to some degree. However, these sets may be used as a safeguard against ‘runaway’ or bolus infusions by either an integrated anti‐siphon valve or an anti‐free‐flow device (Hadaway [112], Quinn [292], Weinstein and Hagle [363]).
- Inclusion of other in‐line devices, for example filters, may also affect the flow rate (Hadaway [112], MHRA [208]).
Vascular access device
The flow rate may be affected by any of the following.
- The condition and size of the vein: for example, phlebitis can reduce the lumen size and decrease flow (Quinn [293], Weinstein and Hagle [363]).
- The gauge of the cannula or catheter (MHRA [208], Springhouse [338], Weinstein and Hagle [363]).
- The position of the device within the vein: that is, whether it is up against the vein wall (Quinn [293]).
- The site of the VAD: for example, the flow may be affected by changes in the position of a limb, such as a decrease in flow when a patient bends their arm if a cannula is sited over the elbow joint (Springhouse [338]).
- Kinking, pinching or compression of the cannula/catheter or tubing of the administration set may cause variation in the set rate (MHRA [208], Springhouse [338]).
- Restricted venous circulation: for example, a blood pressure cuff or the patient lying on the limb increases the risk of occlusion and may result in clot formation (Quinn [293]).
The patient
Patients occasionally adjust the control clamp or other parts of the delivery system (e.g. changing the height of the container), thereby making flow unreliable. Some pumps have tamper‐proof features to minimize the risk of accidental manipulation of the infusion device (Hadaway [112]) or unauthorized changing of infusion device controls (Amoore and Adamson [7]).
Advantages and disadvantages of gravity infusion devices
A gravity flow system is simple to set up. It is low cost and the infusion of air is less likely than with electronic devices (Pickstone [284]). However, the system does require frequent observation and adjustment due to:
- the tubing changing shape over time
- creep or distortion of tubing made of polyvinyl chloride (PVC)
- fluctuations of venous pressure, which can affect the flow of the solution
- the roller clamp can be unreliable, leading to inconsistent flow rates.
There can also be variability of drop size and, if the roller clamp is inadvertently left open, free flow will occur. Infusion rates with viscous fluids can be reduced (particularly if administered via small cannulas) and there is a limitation on the type of infusion as these devices are not suitable for arterial infusions: this is because viscosity and arterial flow offer a high resistance to flow that cannot be overcome by gravity (Pickstone [284], Quinn [293]). If more than one infusion is infusing and one is slower than the other or there is no flow in the second set, then there is a risk of backtracking, which leads to underinfusion or bolus delivery of medicines. The MHRA ([204]) recommends that in these systems, the sets should include anti‐reflux valves.
Gravity drip rate controllers
A gravity drip rate controller is a mechanical device that operates by gravity. These devices use standard solution sets and, although they look much like a pump, they have no pumping mechanism. The desired flow rate is set in drops per minute and controlled by battery‐ or mains‐powered occlusion valves (MHRA [208]).
Advantages and disadvantages of gravity drip rate controllers
Although they can maintain a drip rate within 1% of the target rate, volumetric accuracy is not guaranteed and many of the disadvantages associated with gravity flow still remain. The main advantages are that they are relatively inexpensive and can usually be used with standard gravity sets. They also incorporate some audible and visual alarm systems (MHRA [208]).
Infusion pumps
These devices use pressure to overcome resistance from many causes along the fluid pathway, for example length and bore of tubing or particulate matter in the tubing (Hadaway [112]). There are a number of general features required of infusion pumps.
Accuracy of delivery
In order to meet requirements for high‐risk and neonatal infusions, pumps must be accurate to within ±5% of the set rate when measured over a 60‐minute period, although some may be as accurate as ±2% (Hadaway [112], MHRA [208]). They also have to satisfy short‐term, minute‐to‐minute accuracy requirements, which demand smoothness and consistency of output (MHRA [208]).
Occlusion response and pressure
Flow will occur if the pressure at the tip of an intravascular device is just fractionally above the pressure in the vein; the pressure does not need to be excessive. In an adult peripheral vein, the pressure is approximately 25 mmHg, while in a neonate it is 5 mmHg (Quinn [292]). Most pumps have a variable pressure setting that allows the user to employ their own judgement about the pressure needed to deliver therapy safely. The normal pumping pressure is only slightly lower than the occlusion pressure (Hadaway [112]). Flow is dependent upon pressure divided by resistance. If long extension sets of small internal bore are used, the resistance to flow will increase (Pickstone [284], Quinn [292]).
If an administration set occludes, the resistance increases and the infusion will not flow into the vein. The longer the occlusion lasts, the greater the pressure, and the pump will continue to pump until an occlusion alarm is activated. There are two types of occlusion: upstream (between the pump and the container) and downstream (between the pump and the patient). An upstream occlusion alarm will be triggered when a vacuum is created in the upstream tubing or full reservoir, due to a collapsed or empty plastic fluid container or due to clamped or kinking tubing. A downstream occlusion occurs when the pressure required by the pump exceeds a certain limit of pounds per square inch (psi) to overcome the pressure created by the occlusion. Downstream occlusion pressures range from 1.5 to 15.0 psi (Hadaway [112]).
Pump alarms are triggered at ‘occlusion alarm pressure’, and many pumps allow the user to set the pressure within a range (MHRA [208]). Therefore, the time it takes for an alarm to sound depends on the rate of flow: high rates activate the alarm more quickly. When the alarm is activated, a certain amount of stored medication will be present and it is important that what could be a potentially large bolus is not released into the vein. The release of the stored bolus could lead to rupture of the vein or constitute overinfusion, which may be detrimental to the patient, particularly if it is a critical medication (Amoore and Adamson [7], MHRA [208]). With a syringe pump, to prevent a bolus being delivered to the patient, the clamp should not be opened as this will release the bolus; the first action is to remove the pressure by opening the syringe plunger clamp, following which the occlusion can be dealt with.
A pump's downstream occlusion alarm must not be relied upon to detect infiltration or extravasation (Huber and Augustine [132], Marders [184], MHRA [209]) and routine assessment of intravenous sites is still vital to prevent these complications. Single‐unit variable pressure pump settings that allow an earlier alarm alert are used in neonatal and paediatric units (Quinn [293]).
Air in line
Air‐in‐line detectors are designed to detect only visible or microscopic ‘champagne’ bubbles. They should not create anxiety over small particles of air but alert the nurse to the integrity of the system (MHRA [209]). Most air bubbles detected are too small to have a harmful effect but the nurse should clarify the cause of any alarms (MHRA [208]).
Anti‐siphonage
Uncontrolled flow from a syringe is called ‘siphonage’; this is a result of gravity or leakage of air into the syringe and administration set. Siphonage can occur whether or not the syringe is fixed into an infusion device (Quinn [293]). It has been reported that ‘in practice, a 50 mL syringe attached to a length of administration set with an internal diameter of 3 mm has been shown to empty by siphonage in less than 1 minute’ (Pickstone [284], p.57).
To minimize the risk of siphonage, the following safe practices should be undertaken:
- The syringe (plunger and barrel) should be correctly located and secured (MHRA [209]).
- Intravenous administration extension sets should always be micro or narrow bore in diameter to increase the resistance to flow; wide‐bore extension sets should be avoided.
- The syringe pump should always be positioned at the same level as the infusion site (MHRA [209]).
- Extension sets with an integral anti‐siphonage or anti‐reflux valve should be used (MHRA [204], [208], Quinn [293]).
Safety software: smart pumps
Smart pump technology incorporates safeguards such as a list of high‐alert medications, soft and hard dosage limits, and a drug library that can be tailored to specific patient care areas (Agius [3], Harding [117], Hertzel and Sousa [127]). It has provided an important step in improving patient safety (Breland [30]), and the use of pumps that incorporate this technology is increasingly widespread. A number of studies have evaluated the effectiveness of using smart pumps to prevent medication errors, showing the success of these systems (Dennison [56], Fields and Peterson [93], Larson et al. [169], Manrique‐Rodriguez et al. [183], Rothschild et al. [309]). It is now recommended that nurses use this technology when administering intravenous fluids and medications (Harding [116]), but careful device selection and training are vital for compliance and to ensure safety outcomes (Longshore et al. [175]). Additionally, organizations that provide acute care in the UK have been recommended to minimize the range of device types available and to introduce centralized equipment libraries in order to reduce the chances of user error and improve patient safety (Iacovides et al. [140], NPSA [261]).
Advantages and disadvantages of smart pumps
Smart pumps incorporate technology to improve their ‘intelligence’ when compared to standard volumetric pumps, supporting improved patient safety. Whereas volumetric pumps are predominantly reliant on individual users’ vigilance, smart pumps are able to monitor infusion rates, alert the user if defined dosing limits are exceeded, and generate reports on organizational infusion practices (Breland [30]). The drug library can usually be adapted to individual clinical areas within hospitals, reflecting different dosing requirements across specialities (Heron [126]). Evidence suggests that these features are improving the recognition of user errors, specifically in relation to the programming of doses and infusion rates (Manrique‐Rodriguez et al. [183]).
Smart pumps’ disadvantages are that staff may struggle to introduce these new‐style pumps due to existing device contracts, the infrastructure and resources required to use them fully (such as their wireless features), and financial constraints (Iacovides et al. [140]).
Volumetric pumps
Volumetric pumps (Figure 15.35) pump fluid from an infusion bag or bottle via an administration set and work by calculating the volume delivered (Quinn [293]). This is achieved when the pump measures the volume displaced in a ‘reservoir’. The reservoir is an integral component of the administration set (Hadaway [112]). The mechanism of action may be piston or peristaltic (Hadaway [112]). The indications for use are all large‐volume infusions, both venous and arterial.
Figure 15.35 Volumetric pump.
All volumetric pumps are mains and battery powered, with the rate selected in millilitres per hour. The accuracy of flow is usually within ±5% when measured over a period of time, which is more than adequate for most clinical applications (MHRA [208], Pickstone [284]).
Advantages and disadvantages of volumetric pumps
These pumps are able to overcome resistance to flow by increased delivery pressure and do not rely on gravity. This generally makes the performance of these pumps predictable, and they are capable of accurate delivery over a wide range of flow rates (MHRA [208]).
Volumetric pumps also incorporate a wide range of features, including air‐in‐line detectors, variable pressure settings and comprehensive alarms, such as ‘end of infusion’, ‘keep vein open’ (where the pump switches to a low flow rate, e.g. 5 mL/h, in order to continue flow to prevent occlusion of the device) and ‘low battery’. Many have a secondary infusion facility, which allows for intermittent therapy, for example antibiotics. The pump is programmed to switch to a secondary set and, when completed, it reverts back to the primary infusion at the previously set rate. The changing hospital environment has led to increased demand on volumetric pumps, which in turn has resulted in the development of multichannel and dual‐channel infusion pumps. These may consist of two devices with an attached housing or of several infusion channels within a single device (Hadaway [112]).
The disadvantages of volumetric pumps are that they are usually relatively expensive, and often dedicated administration sets are required. The use of the wrong set could result in error even if the pump appears to work. Some are complicated to set up, which can also lead to errors (MHRA [208]).
Syringe pumps
Syringe pumps (Figure 15.36) are low‐volume, high‐accuracy devices designed to infuse at low flow rates. The plunger of a syringe containing the substance to be infused is driven forward by the syringe pump at a controlled rate to deliver the substance to the patient (MHRA [208]).
Figure 15.36 Syringe pump.
Syringe pumps are useful where small volumes of highly concentrated drugs need to be infused at low flow rates (Quinn [293]). The volume for infusion is limited to the size of the syringe used in the device, which is usually 60 mL, but most pumps will accept different sizes and brands of syringe.
These devices are calibrated for delivery in millilitres per hour (Weinstein and Hagle [363]).
Advantages and disadvantages of syringe pumps
Syringe pumps are mains and/or battery powered, are usually easy to operate, and tend to cost less than volumetric pumps. The alarm systems have become more comprehensive and include ‘low battery’, ‘end of infusion’ and ‘syringe clamp open’ alarms. Most of the problems associated with the older models – for example, free flow, mechanical backlash (slackness that delays the start‐up time of the infusion) and incorrect fitting of the syringe – have been eliminated in the newer models (MHRA [208], Quinn [293]). The risk of free flow is minimized by the use of an anti‐siphonage valve, which may be integral to the administration set (Pickstone [284]). Despite the use of an anti‐siphonage valve, the clamp of the administration set must still be used (MHRA [208]). Where mechanical backlash is an issue and there is a prime (also called purge) option, this should be used at the start of the infusion to take up the mechanical slack (Amoore et al. [8]).
Specialist pumps
Patient‐controlled analgesia pumps
Patient‐controlled analgesia (PCA) devices are typically syringe pumps (although some are based on volumetric designs) (MHRA [208]) (Figure 15.37). The syringe pump forces down the syringe piston, collapsing the syringe at a pre‐set rate, but the distinguishing feature is the ability of the pump to deliver doses on demand, which occurs when the patient pushes a button (Schug et al. [326]). Whether or not the dose is delivered is determined by pre‐set parameters in the pump. That is, if the maximum amount of drug over a given period of time has already been delivered, a further dose cannot be delivered.
Figure 15.37 Patient‐controlled analgesia (PCA) pump, generally used in acute hospital settings.
PCA pumps are useful for patients who require pain control. They are used most commonly in the acute setting but are also useful in ambulatory situations (Schug et al. [326]).
The infusion options of a PCA pump are usually categorized into three types:
- PCA demand mode only: drug delivered by intermittent infusion when a button is pushed. Doses can be limited to a designated maximum amount (Macintyre and Schug [180]).
- Continuous: designed for patients who need maximum pain relief without the option of demand dosing (e.g. epidural).
- A combination of PCA demand mode with a continuous infusion (background): a small dose of opioid is delivered in the background in addition to PCA demand dosing. This option may be useful if patients are on high‐dose opiates or have high pain levels (Schug et al. [326]).
PCA pumps can dispense a bolus dose, with an initial bolus being called a ‘loading dose’. This may benefit patients as the one‐time dose is significantly higher than a demand dose in order to achieve immediate pain relief (see Chapter c09: Patient comfort and supporting personal hygiene and Chapter c11: Symptom control and care towards the end of life).
Advantages and disadvantages of patient‐controlled analgesia pumps
To ensure patient safety, a key or software code is needed to access control of the pump. In addition, these devices offer a ‘clinician override’ feature with a predetermined key code to enable authorized personnel to modify running programmes in specific clinical situations. They have an extensive memory capability, which can be accessed through the display via a printer or computer (MHRA [208]). This facility is critical for the pumps’ effective use in pain management (Hadaway [112]), as it enables clinicians to determine when and how often demand is made by a patient and what total volume has been infused (Hadaway [112]). It has also been shown that PCA pumps increase patient satisfaction and also reduce their anxiety, their nursing needs and their time in hospital (McNicol et al. [192]).
While PCA pumps have advantages in relation to safety and efficacy, there is still a risk of adverse events, such as respiratory depression, with a continuous background infusion (Schug et al. [326]).
Anaesthesia pumps
Anaesthesia pumps are syringe pumps designed for delivery of anaesthesia or sedation and must only ever be used for those purposes. They should be restricted to operating theatres and critical care units, and should be clearly labelled. They are designed to allow rapid changes in flow rate and bolus to be made while the pump is infusing (Quinn [293]). Total intravenous anaesthesia (TIVA) and target‐controlled infusion (TCI) pumps are available, designed to control the induction, maintenance and reversal phases of anaesthesia (Absalom and Struys [1]).
Epidural pumps
Epidural pumps (Figure 15.38) provide analgesia (most commonly a combination of opioids and anaesthetic agents) via a fine catheter inserted directly into the epidural space. As a form of analgesia delivery, the efficacy of the epidural route has been well documented (Block et al. [24], Werawatganon and Charuluxanun [364], Wheatley et al. [367]) and it is used effectively in several specialities, across medical and surgical settings (Gizzo et al. [105], Janaki et al. [144]). See also Chapter c09: Patient comfort and supporting personal hygiene and Chapter c11: Symptom control and care towards the end of life.
Figure 15.38 Epidural pump.
Ambulatory infusion devices
Ambulatory infusion devices were developed to allow patients more freedom and to enable patients to continue with normal activities or to move unencumbered by a large infusion device (Hadaway [112]). Ambulatory devices range in size and weight. They are used for small volumes of drugs and are mainly designed for patients to wear and use when ambulant. The solution containers are often more cumbersome than the actual pump itself. Due to their size, the number of alarms may be limited. Considerations for selection of an ambulatory device include the following:
- type of therapy
- patient's ability to understand how to manage the infusion device
- drug stability
- frequency of doses
- reservoir volumes required
- control of flow and flow rate
- type of access
- cost‐effectiveness
- portability
- convenience.
Ambulatory pumps fall into two categories: mechanical and battery‐operated infusion devices.
Mechanical infusion devices
These are simple and compact but may not necessarily be cost‐effective as they are usually disposable. The mechanism for delivery is by balloon or simple spring, or they may be gas powered. They are usually very user friendly as they require minimal input from the patient and no battery. They can also be purchased pre‐filled (Quinn [293]). Their flow rates are influenced by pressure gradient, viscosity and temperature, which can lead to inaccuracies (Ackermann et al. [2], HWR [137], Skryabina and Dunn [335]).
Mechanical infusion devices have two types:
- Elastomeric balloon devices: these are made of a soft rubberized material capable of being inflated to a predetermined volume, and the drug is then administered over a very specific infusion time. The balloon is encapsulated inside a rigid transparent container, which may be round or cylindrical. The rate of infusion is not controlled by the balloon but by the diameter of the restricting outlet, located in the pre‐attached tubing (Quinn [293]). These devices are designed to supply a patient's need for a single‐dose infusion of drugs (e.g. intermittent small‐volume parenteral therapies, such as antibiotics). Their small size causes little disruption to the patient's daily activities and they tend to be well tolerated (Broadhurst [32], Hadaway [112]). Figure 15.39 shows an elastomeric device.
- Spring mechanism: spring coil piston syringes have a spring that powers the plunger of a syringe in the absence of manual pressure. The volume is restricted by the size of the syringe, which is usually pre‐filled. The spring coil container tends to be a multidose, small‐volume administration device and is a combination of a spring coil in a collapsible flattened disc. Its shape can accommodate many therapies and volumes (Hadaway [112]).
Figure 15.39 Elastomeric device.
Battery‐operated infusion devices
Battery‐operated pumps are small and light enough to be carried around by the patient without interfering with most everyday activities. They are operated using rechargeable or alkaline batteries but, owing to their size, the available battery capacity tends to be low. The length of time the battery lasts is often dependent on the rate at which the pump is set. Most give an output in the form of a small bolus delivered every few minutes, and most have an integral case or pouch that allows the pump and the reservoir or syringe to be worn with discretion by the patient.
There are two types: ambulatory volumetric infusion pumps and syringe drivers. Both are infusion devices that pump in the same way as a large volumetric pump; however, by nature of their size, they are portable and useful in the ambulatory setting (hospital or home care) (MHRA [209]).
These pumps are suitable for patients who have been prescribed continuous infusional treatment for a period of time, for example from 4 days to 6 months. They enable patients, where appropriate, to receive treatment at home, because they are small and portable.
Advantages and disadvantages of ambulatory infusion devices
The advantages of ambulatory pumps are as follows:
- They are able to deliver drugs continuously or intermittently.
- They can be used with a variety of infusion routes: central, peripheral venous, epidural, intra‐arterial, intrathecal and subcutaneous.
- They deliver drugs accurately over a set period of time.
- They can improve the outcomes of treatment by delivering treatment continuously.
- They heighten the patient's independence and control by allowing them to be at home and participate in their own care.
- They are compact, light and easy to use.
- They have audible alarm systems.
The disadvantages of ambulatory pumps are as follows:
- They may require the insertion of a central venous access device, which has associated complications and problems.
- They may malfunction at home, which could be distressing and dangerous for the patient.
- In spite of their ease of use, some patients may not be able to cope with them at home.
- Patients may have to adapt their lifestyle to cope with living with a pump continuously (MHRA [209]).
Specific patient preparation
Selecting the appropriate infusion device for the patient
The nurse has a responsibility to determine when and how to use an infusion device to deliver hydration, drugs, transfusions and nutritional support, and how to select the most appropriate device to manage the needs of the patient. The following factors should be considered when selecting an infusion delivery system (Quinn [293]):
-
Risk to the patient of:
- overinfusion
- underinfusion
- uneven flow
- inadvertent bolus
- high‐pressure delivery
- extravascular infusion.
-
Delivery parameters:
- infusion rate and volume required
- accuracy required (over a long or short period of time)
- alarms required
- ability to infuse into site chosen (venous, arterial or subcutaneous)
- suitability of the device for infusing the required drug (e.g. ability to infuse viscous drugs).
-
Environmental features:
- ease of operation
- frequency of observation and adjustment
- type of patient (e.g. neonate, child or critically ill)
- mobility of patient.
Paediatric considerations
The MHRA ([210]) classifies infusions into categories of risk. Neonatal infusions are the highest risk category, and infusion of fluids in children carries the next highest level of risk, as accuracy in the flow rate is essential. Infusion therapy within the paediatric setting requires very specific skills (Frey and Pettit [99]). It is paramount for practitioners to be competent in calculating paediatric doses, maintaining a stringent fluid balance, using paediatric‐specific devices and managing complications.
The MHRA ([208]) has published recommendations on the safety and performance of infusion devices in order to enable users to make the appropriate choice of equipment to suit most applications. These recommendations include a classification system that is divided into three major categories according to the potential risks involved. These are shown in Table 15.13. A pump suited to the most risky category of therapy (A) can safely be used for the other categories (B and C). A pump suited to category B can be used for B and C, whereas a pump with the lowest specification (C) is suited only to category C therapies (MHRA [208]) (Figure 15.40). Hospitals are required to label each infusion pump with its category, and it is necessary to know the category of the proposed therapy and match it with a pump of the same or a better category. A locally produced list of drugs and fluids along with their categories will need to be provided to all device users (MHRA [208]).
Table 15.13 Therapy categories and performance parameters
| Therapy category | Therapy description | Patient group | Critical performance parameters |
|---|---|---|---|
| A | Drugs with a narrow therapeutic margin | Any |
Good long‐term accuracy
Good short‐term accuracy |
| Drugs with a short half‐life | Any | Rapid alarm after occlusion | |
| Any infusion given to neonates | Neonates |
Small occlusion bolus
Able to detect very small air embolus (volumetric pumps only)
Small flow rate increments
Good bolus accuracy
Rapid start‐up time (syringe pumps only) | |
| B | Drugs other than those with a short half‐life | Any except neonates |
Good long‐term accuracy
Alarm after occlusion |
| Parenteral nutrition | Volume sensitive except neonates | Small occlusion bolus | |
| Fluid maintenance | Volume sensitive except neonates | Able to detect small air embolus (volumetric pumps only) | |
| Transfusions | Volume sensitive except neonates | Small flow rate increments | |
| C | Diamorphine | Any except neonates | Bolus accuracy |
| Parenteral nutrition | Any except volume sensitive or neonates | Long‐term accuracy | |
| Fluid maintenance | Any except volume sensitive or neonates | Alarm after occlusion | |
| Transfusions | Any except volume sensitive or neonates |
Small occlusion bolus
Able to detect air embolus (volumetric pumps only)
Incremental flow rates |
Figure 15.40 Decision tree for selection of an infusion device. Source: Adapted from MHRA ([208]). © Crown copyright. Reproduced under the Open Government Licence v2.0.
Procedure guideline 15.23
Medication: continuous infusion of intravenous drugs
Procedure guideline 15.24
Medication: intermittent infusion of intravenous drugs
Procedure guideline 15.25
Medication: injection (bolus or push) of intravenous drugs
| Problem | Cause | Prevention | Action |
|---|---|---|---|
| Infusion slows or stops due to a change in position of the patient or any equipment | Patient has changed position | Check the height of the fluid container if the patient is active and receiving an infusion using gravity flow. | Adjust the height of the container accordingly. The infusion should not hang higher than 1 m above the patient as the increased height will result in increased pressure and possible rupture of the vessel or device ( Quinn [293]). |
| Limb has changed position |
Avoid inserting peripheral devices at joints of limbs.
Instruct the patient on the amount of movement permitted. Continued movement could result in mechanical phlebitis (
Lamb and Dougherty [162]). | Move the arm or hand until the infusion starts again. Secure the device, then bandage or splint the limb again carefully in the desired position. Take care not to cause damage to the limb. | |
| Administration set has moved | Tape the administration set so that it cannot become kinked or occluded. | Check for kinks and/or compression if the patient is active or restless, and correct accordingly. | |
| Cannula has moved | Secure the cannula firmly to prevent movement. It may come into contact with the vein wall or a valve. Infusions sited in small veins are prone to this problem. | Remove the bandage and dressing and manoeuvre the peripheral device gently, without pulling it out of the vein, until the infusion starts again. Secure adequately. | |
| Infusion slows or stops due to technical problems | Negative pressure prevents flow of fluid | Ensure that the container is vented using an air inlet. | Vent if necessary, using a venting needle. |
| Empty container | Check fluid levels regularly. | Replace the fluid container before it runs dry. | |
| Venous spasm due to chemical irritation or cold fluids/drugs |
Dilute drugs as recommended.
Remove solutions from the refrigerator a short time before use. | Apply a warm compress to soothe and dilate the vein, increase the blood flow and dilute the infusion mixture. | |
| Injury to the vein | Detect any injury early as it is likely to progress and cause more serious conditions. | Stop the infusion and re‐site the cannula. | |
| Occlusion of the device due to fibrin formation | Maintain a continuous, regular fluid flow or ensure that patency is maintained by flushing. Instruct the patient to keep their arm below the level of the heart if ambulant and attached to a gravity flow infusion. |
If peripheral device: remove extension set/injection cap and attempt to flush the cannula gently using a 10 mL syringe of 0.9% sodium chloride. If resistance is met, stop and re‐site the peripheral device (see Chapter c17: Vascular access devices: insertion and management).
If central venous access device: remove injection cap and attempt to flush the cannula gently using a 10 mL syringe of 0.9% sodium chloride. If resistance is met, attempt to instil a fibrinolytic agent such as urokinase (see Chapter c17: Vascular access devices: insertion and management). | |
| The cannula has become displaced either completely or partially; that is, fluid or drug has leaked into the surrounding tissues (‘infiltration’; if the drugs were vesicant in nature, this would then be called ‘extravasation’) | Secure the cannula and tape the administration set to prevent pulling and dislodgement. Instruct the patient on the amount of movement permitted regarding the limb that has the device in situ ( Fabian [90]). |
Confirm that infiltration of drugs has or has not occurred by:
If infiltration is confirmed, stop the infusion and request a re‐siting of the device. If the infusion is allowed to progress, discomfort and tissue damage will result. Apply cold or warm compresses (whichever provides the most comfort for the patient) to provide symptomatic relief. Reassure the patient by explaining what is happening. Document the incident in the care plan and monitor the site (
Lamb and Dougherty [162]).
If extravasation occurs, follow hospital policy and procedure. | |
| Infusion pump alarm: air detected | Air bubbles in administration set | Ensure all air is removed from all equipment prior to use. | Remove all air from the administration set and restart the infusion. |
| Infusion pump alarm: tube misload | Administration set has been incorrectly loaded | Ensure the set is loaded correctly. | Check that the set is loaded correctly and reload if necessary. |
| Infusion pump alarm: upstream occlusion | Closed clamp, obstruction or kink in the administration set is preventing fluid flow | Ensure the container/fluid bag has been adequately pierced by the administration spike. | Inspect the administration set and restart the infusion. |
| Ensure the tubing is taped to prevent kinking. | If tubing is kinked, reposition, tape and restart infusion. | ||
| Ensure the regulating (roller) clamp is open. | Check the administration set and open the clamp; restart the infusion. | ||
| Infusion pump alarm: downstream occlusion | Phlebitis/infiltration or extravasation | Observe the site regularly for signs of swelling, pain or erythema. | Remove the peripheral device, provide symptomatic relief where appropriate. Initiate extravasation procedure. Re‐site as appropriate. |
| Closed distal clamp | Ensure clamps are open. | Locate distal occlusion and restart infusion. | |
| Infusion pump alarm: KVO (keep vein open) alert | The volume infused is complete and the device is infusing at the KVO rate | Programme in a new volume as appropriate. |
Do not turn the device off. Allow KVO mode to run to maintain the patency of the device.
Prepare a new infusion or discontinue as appropriate. |
| Infusion device malfunctioning (electrical/mechanical) | Not charging at mains | Ensure that the device is kept plugged in where appropriate. | Change device and remove device from use until fully charged. Send to clinical engineering to check plug. |
| Low battery | Push lead in adequately. | Check lead is pushed in adequately. Contact clinical engineering if fault persists. | |
| Batteries keep requiring replacement | Do not use small rechargeable batteries in ambulatory devices. | Ensure non‐rechargeable batteries have been used. Contact clinical engineering if fault persists. | |
| Technical fault | Ensure all infusion devices are serviced regularly. | Remove infusion device from use and contact clinical engineering department or relevant personnel. | |
| Device soiled inside mechanism | Maintain equipment and keep clean and free from contamination. | Remove administration set, wipe pump and reload. Do not use alcohol‐based solutions on internal mechanisms. | |
| Unstable infusion device. | Mounted on an old, poorly maintained stand |
Ensure that stands are maintained and kept clean.
Replace old stands. | Remove device from stand. Remove stand and send to clinical engineering for repair. |
| Mounted on an incorrect stand | Ensure the correct stands are used. | Check the stand and change to an appropriate stand. | |
| Equipment not balanced on stand | Ensure that all equipment is balanced around the stand. | Remove the devices and attach them to two stands if necessary. Balance the equipment. |
Post‐procedural considerations
Ongoing care
Monitoring of the infusion while in progress includes monitoring the patient's condition and response to therapy, the VAD site, the rate and the volume infused. It may also include monitoring the battery life and occlusion pressure. The frequency of monitoring is often based on the type of therapy and the patient's condition; for example, the rate of infusion and the infusion site may be checked 15 minutes after setting up the infusion, then again after 1 hour and then 4‐hourly (or more frequently depending on the medication). The check must be documented on the patient's fluid balance chart or in their notes. The type and make of pump along with the serial number should also be documented (this is useful if any errors occur) (MHRA [205]).
Complications
In cases of phlebitis, thrombosis, septicaemia or embolism, see Chapter c17: Vascular access devices: insertion and management.
