The most common question asked of experienced nurses in the ICU where CRRT is performed frequently is their opinion for machine choice and other treatment preferences. Depending on global location, regional availability, past or existing hospital contracts, leading physician input, and available budget, the choice will vary widely. Many suppliers are now offering flexible contracts where the high purchase cost is removed for acquisition of machines, but built into an anticipated consumables use contract over a number of years into the future.

While interface and appearance will differ, machines for CRRT mostly differ in the manner in which they control fluids measurement to achieve fluid balance [24, 25]. They all offer a version of pre-assembled disposable circuitry, colour monitor screen user interface with touch or control knob navigation and roller pumps to provide blood and fluids flow [8, 26, 27]. An internal computer manages the system reliant on pressure readings, sensors and detectors from the circuit to facilitate correct software function from the priming phase and during use. This functionality is to detect errors preventing major failure likely to cause death such as air embolism [28] or fluid imbalance [24, 25]. This is a complex requirement and generally done well by manufacturers. Figure 21.2 provides a generic circuit diagram for any automated CRRT machine and circuit indicating key sensors and detectors with common pressure readings from the circuit linked into machine software. Table 21.1 indicates a suitable troubleshooting and shift check for any automated scale-based CRRT machine associated with this circuit diagram and the pressures – sensors indicated.

Fluid measurement is done by direct volume measurement technology along the fluid pathways or by simple electronic scales assessing a change in substitution (decreasing weight) and waste (increasing) weights [24, 25]. A difference between these two measures is the fluid ‘balance’; usually a loss, or more fluid in the waste compared to the fluid replacement.

Accuracy of the fluids management and how this links into the user interface setting for a desired treatment with accurate fluid removal is the challenge for manufacturers to provide safety with suitable alarms systems for the user to be aware of error. This aspect of CRRT machines creates the most concern for safe use, particularly in paediatrics with regulatory and published reports of morbidity and mortality due to fluid setting error or failure to respond to fluids alarms in adults, children and small babies [24]. When reviewing a number of different machines for purchase, a simple practical specifications table is useful. This allows the selection team to include the local preferences, required options and needs for comparison and review in order to support their final decision. A selection team needs to be inclusive of nurses, doctors, pharmacy, biomedical or technical support, fund or budget managers and nurse teachers. Practical bedside use is an important consideration throughout; therefore, machine footprint or monitor screen adjustment may need to be highly ranked in a selection table given the usual cluttered ICU bedside space or user interface with a focus on how easy the machine is to teach another nurse.

Another important consideration for machine choice is the disposable circuit necessary and how this is supplied and when fitted connects the machine to the patient, and importantly the composition and size of the membrane used, and costing for all. The circuit tubing configuration and quality of this vital component are often overlooked due to a focus on the software offerings and other options in a machine.

A protocol for CRRT in the ICU means a document with instructions for use designed and prepared by clinicians in a specific ICU. Although key aspects of a CRRT protocol may be applicable to any ICU, the idiosyncrasies and local context needs to be added and incorporated into this important resource for safe use of CRRT in your ICU. Using the protocol from another ICU is a mistake and should not be done, but is a useful guide or example to develop your own [17]. The protocol will have a practical focus with most content devoted to ‘how to do’ CRRT with the patients in your care, the machine used and the CRRT method chosen [1, 5, 17, 19].

Key headings for the protocol are set out in Fig. 21.3. This document is usually read as a digital file via bedside computer and allows use of colour diagrams, may include hyperlinks to different sections of the document from key words or as an index function at the front of the protocol. This allows readers to find what they need quickly. In addition, hyperlinks to other hospital policies and protocols relevant to CRRT within a local network, intranet or Internet (http:WWW) make for fast and helpful referencing. Reviewing and updating the CRRT protocol is a time-consuming task and needs to be done in-line with latest evidence, how this may alter practice, changes to consumables used and any new techniques developed such as plasma exchange (PE) or other blood purification methods; this is the role of a small interest group and the nurse and doctor champions or key experts in CRRT. Some sections of the protocol may be printed for single use or laminated within plastic for use at a bedside by the nurse managing the CRRT repeatedly across several patients. Anticoagulation technique is a good example of this, where there may need to be drug infusion adjustments according to regular blood testing. Citrate anticoagulation is a good example where the ionised calcium level requires maintenance and is checked frequently for adjustment to calcium infusion supplementation [29, 30]. Reportable parameters for when acid–base and total calcium levels require intervention will also be included as they are not easy to remember and terminology and acronyms used may create confusion and error. There are some publications devoted to content of a CRRT protocol and provide a step-by-step approach beginning with criterion for starting CRRT, how to prepare the patient and the machine – circuit, connecting and beginning a treatment, manage and troubleshoot treatment in progress, commonly include a focus to anticoagulation approaches, and finally when and how to cease CRRT [15].

The protocol is not a machine instruction for use document and is different to the technical manual supplied with a machine; however, there may be some technical information in a manual useful to include in the protocol such as machine’s battery life, significance of unusual error codes and maintenance or calibration requirements.

The protocol can be a useful educational tool, and should be used this way. Inclusion of research evidence with citations, weblinks, diagrams and tables will help keep the document limited in size and staff should be encouraged to have copies of the protocol. This will also help the reviewing team keep the protocol current and correct as these people will provide feedback if they encouraged to read, use and have their own copy.

Maintaining expertise using CRRT in the ICU will be influenced by the frequency of use or number of cases treated annually and the size of the user pool. Some programmes utilize regular competency checks and assessments [20, 21] and where use is frequent this is not done allowing the constant exposure of nurses to CRRT use provide the competency process. Different levels of skills sets can be determined for nurse to patient allocation; therefore, controlling learning and providing some safety for the patient being managed by a nurse with the appropriate CRRT skills set [1, 19]. In either case, when expert users or CNS nurses with CRRT expertise work adjacent to or close to new learners, they should be encouraged to review treatments, teach and advise. Teaching can be achieved by reviewing treatments, their progress and anticipated problems with live use of CRRT at the bedside, at the time; the teaching ‘moment’ such as this will be remembered by the learner, gives them reassurance and ensures safety as small errors may be detected before they create changes to patient stability. Electrolyte control such as potassium levels or anticoagulation dosing, for example. In addition to this framework and teaching culture among nurses in the ICU, pre-connection or preparation checklists, during use shift checklists (see Table 21.1), quick reference alarms and troubleshooting sheets available through bedside clinical information and e-protocol systems are very helpful to maintain skills and ensure standards are maintained. Regular group mini-simulations, review of incident or adverse events associated with CRRT, machine repair reports from technicians, tutorials, case presentations within an in-house education structure at nurse handover periods all ensure safety and quality is promoted [31].