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Published on 1 November 2007

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Safety features of smart infusion

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Linda Murdoch
MB BS FRCA

Lead Clinician

Paediatric Intensive Care Unit
St George’s Hospital
London
UK

E: linda.murdoch@stgeorges.nhs.uk

Preventing intravenous medication errors is a challenge requiring a multimodal approach. Standard infusion pumps do not alert for or prevent drug-calculation, drug-unit, button-push or multiple-of-10 errors when data is entered at the interface. Clear evidence exists that smart infusion pumps including a drug library to alert the clinician if a programming entry is attempted outside preset parameters can allow a significant cut in infusion-related errors in intensive care units (ICUs).

St George’s paediatric ICU wanted to implement a system that would be immediately effective in cutting medication errors at the administration point. We chose a smart system with unique two-channel relay: Fresenius Kabi’s Orchestra infusion workstation, comprising Base Intensive, Module DPS syringe pumps and Module MVP volumetric pumps.

 

Drug library
Although the syringe and volumetric modules can operate independently, additional functionality is achieved when they are connected to a Base Intensive. Any combination of up to eight syringe and volumetric pumps can be stacked and connected to one Base Intensive. Its screen displays all drug and fluid infusions, enabling visualisation of infusion position in the stack, and for the Module DPS the drug name, dilution, flow rate and dose rate.

The main safety feature of any smart infusion system is the drug library. Base Intensive has a 150-item library, but its real benefit is that it can be customised to individual units’ requirements. Software customisation requires a team approach, with time investment from pharmacist, doctor and nurse.

Programmable parameters are minimum, typical and maximum values for drug concentration, loading and bolus dose and infusion rate. The drug library is stored and modified on a computer and downloaded onto each Base Intensive. The process is so simple that we consider our library to be in constant evolution and can maintain an up-to-date unit-specific library. Load and/or bolus functions can be disabled. These programmed doses have become a vital tool for staff, ensuring safe load and bolus doses.

It is possible to add comments for individual drugs in the library. These are then displayed on the Base Intensive screen when infusions are programmed and this key information is conveyed to users.

Smart pumps can have soft and/or hard limits, and there is much discussion in the literature about the risk-benefit profile of each setting. Soft limits can be overridden by the clinician using the pump, while hard limits cannot. In theory, soft limits provide more flexibility, letting clinicians make the ultimate decision on infusion parameters. But in practice they can negate the purpose of having a drug library, which is to stop clinicians programming outside preset safe limits. Orchestra has only hard limits.

The user can view on the Base Intensive all pre-set parameters and comments on any drug in the library, not just those infusing. This provides a good prescribing resource. For increased safety at each stage, the Base Intensive connects to Fresenius Vigilant, comprising Vigilant Barcode, syringe identification system using a barcode sticker with the drug name, dilution and patient name; Vigilant Drug’Lib, which enables several user identities to be created for the same workstation (for each user − physician or unit − a personalised drug library can be created); and Vigilant Supervision, offering a central monitor display of every alarm and intravenous drug administration parameter for all connected patients.

Two-channel relay
In critical care, administration of vasoactive drugs to support cardiovascular function must be continuous due to their short halflife. To maintain uninterrupted administration, one infusion starts when the other is near-empty – a technique called “double pumping”.[1] Failing to double-pump successfully can interrupt drug flow or cause excess delivery, leading to cardiovascular instability. Whichever double-pumping method is used, the patient is liable to experience periods of hypotension, hypertension and cardiovascular instability due to the mechanics of the infusion device, the double-pumping technique or the nurse’s level of experience.[2]

A safer method for continuous administration of inotrope infusions incorporated into the Orchestra system is two-channel relay − a mechanism for associating two channels (Module DPS), one that is currently infusing the drug, the other that will take this over. The channels are associated via the Base Intensive so the second channel automatically starts infusing as the rate of the first reduces. This keeps a constant infusion rate and removes the human interface associated with traditional double-pumping.

There is little published data on two-channel relay but our experience, after nearly five years’ use, shows this to be an efficient way to maintain cardiovascular stability. We have data awaiting publication which demonstrate this.

The channel relay link can be established up to 24 hours in advance, enabling efficient use of nursing staff. When two nurses are available they can check and make up the infusion, install the syringe and set up the relay link several hours in advance.

History data
Orchestra allows easy access to date- and time-logged drug history and module events, which can be patient-referenced. This provides invaluable educational, clinical governance and medicolegal data, stored by the Base Intensive for 96 hours in real time. It is possible to interrogate the history more fully and for longer by downloading stored information, with 8,000 events retrievable.

Fluid management
Accurate fluid management is essential in critical care. With Orchestra, the input side of the fluid balance screen shows the total volumes infused by all modules in the balance period. Volumes of all other inputs and all outputs must be entered manually, to give an overall balance. With the growing prevalence of data management and paperless systems, the advantages of this type of system are evident as balances can be directly dumped into any of several commercially available ICU database programmes.

Pressure management
Orchestra has two complementary pressure management systems: the unique dynamic pressure system (DPS) and standard occlusion alarms. The DPS detects pressure in the line, alerting to a disconnection. In partial occlusion due to distal obstruction such as phlebitis and extravasation, pressure may gradually rise due to increased resistance at the infusion site, although this may not suffice to trigger the standard occlusion alarm. In some circumstances Orchestra DPS can detect and warn of this gradual pressure rise, allowing faster occlusion detection.

Conclusion
When we set out to upgrade our infusion technology, drug administration safety and infusion pump drug error reduction were of highest importance. The hospital did not use other error safeguard systems such as computerised physician order entry or barcode medication administration, so we needed a standalone system that would immediately impact at the point of administration. Critical incidents in the ICU have become rare since we implemented Orchestra with customised drug library, two-channel relay and safety features. Our data proves it.

References
1. Crisp H. Minimising the risks: safe administration of inotropic drug infusions in intensive care. Nurs Crit Care 2002;7(6):283-9.

2. Trim JC, Roe J. Practical considerations in the administration of intravenous vasoactive drugs in the critical care setting: the double pumping or piggyback technique. Part 1. Intensive Crit Care Nurs 2004;20(3):153-60.

 



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