Computer cart specifications: battery, hardware, retrofitting

In 2023 the Fraunhofer IML published a study conducted in three German hospitals on 74 care professionals.
When interviewed, they estimated the time spent documenting care activities at 52 minutes per shift; measurement with wearable sensors recorded an average of 109, more than double, almost a quarter of a 7.8-hour shift. It is not an isolated finding: a time-and-motion analysis published in 2021 in the Journal of Emergency Nursing reached an even sharper result, with emergency-department nurses engaged with the electronic health record for 27% of the shift, more than the time devoted to direct patient care (25%).

These figures change the nature of a purchase that many facilities still treat as furniture: the computerized cart, the “computer on wheels” of the international literature, is the physical point where the electronic health record meets the ward. If documentation takes up such a large share of the shift, and if those who carry it out systematically underestimate its weight, the choice of that cart is a multi-year operational decision, because the frame will outlast two or three generations of the computing devices it carries.

Before runtime comes the power architecture

Before even reading a runtime figure, it is worth clarifying how the cart draws power, because the architectures on the market differ and change the very nature of the assessment.

1. The first is the battery integrated into the cart: an accumulator housed in the structure, recharged by plugging the cart into a mains socket, which powers both the computing device and the accessories. It is typically paired with a monitor and mini PC, or with a medical all-in-one computer (there are also panel PCs without hot-swap batteries, which therefore need to be powered by an integrated battery). These two configurations, together with the laptop option for the MediPod, are the most requested. The usage logic is that of a household appliance: you put it on charge at the end of the shift and it requires no further management
2. The second is hot-swap batteries: removable accumulators, usually housed inside a medical all-in-one PC, which are replaced without switching off the workstation and recharged in dedicated stations or racks. An all-in-one computer can hold more than one. The advantage is real and should be acknowledged: the workstation never goes out of service, because a flat battery is replaced in a few seconds with a charged one, and runtime no longer depends on the health of a single accumulator
3. The third is mains power with a UPS: the cart normally stays plugged in and the battery, sized for continuity only, covers movements and voltage fluctuations. It suits workstations that move little

The real comparison, today, is between the first two, and it turns not on technology but on the cost of management. Hot-swap batteries are expensive and delicate, and above all they have to be managed like a device fleet: each accumulator requires a daily check of its charge state, dedicated charging stations and a stock of charged batteries kept within reach of the ward. If a panel PC holds three batteries and a ward has ten workstations, staff find themselves watching over several dozen accumulators, hunting for charged ones and moving them between floors. The integrated battery shifts this burden upstream: it recharges by plugging the cart into the socket and asks for no daily management, at the price of having to go back on charge when runtime runs out. Something that weighs most where use is continuous around the clock. In every case, the runtime always covers a full working shift.

The specification to consider therefore changes with the architecture. For the integrated battery the decisive question is real runtime, the subject of the section that follows. For hot-swap, the assessment moves to fleet management: the supplier must state how many batteries are needed per workstation, the runtime of each, the recharge times and methods, and how stocks are organised.

It holds for us too: Francehopital computer carts ensure up to 8 hours of runtime and a full recharge in no more than 4 hours.
These are laboratory figures and, like all laboratory figures, they should be questioned: the right question is not how many hours the manufacturer declares, but how many the product guarantees under the ward’s conditions of use. The specification to weigh in the assessment should therefore be framed declaratively: the system must guarantee runtime under variable load for the full length of a shift, with the monitor on and the PC in continuous use; as an operational benchmark, at least 6 hours under these conditions.

Alongside runtime, three items that rarely receive the same attention: the full recharge time (it determines whether the cart recovers in the break between shifts or stays idle); the number of charge cycles before significant degradation (it determines when the battery becomes a replacement cost); the planned charging method, because it affects the organisation of parking spaces on the ward.

The computing component is configured in two ways, not one

About the cart’s computing side a simplification circulates that is worth dismantling at once: “the computer on the cart”.
In reality there are two possible configurations, with distinct assessment parameters.

1. The first: an all-in-one panel computer, ideally, mounted directly on the cart’s VESA fitting. It is the most compact configuration; screen and computing unit coincide, cable management is reduced, but replacing one component means replacing the whole device
2. The second: a monitor mounted on the VESA fitting and cabled to a separate computing unit, a mini PC or a thin client housed in a dedicated compartment, or a laptop connected to the larger monitor. It is the more flexible configuration; monitor and computing unit are replaced independently and at separate costs, at the price of an extra cable run to protect and keep tidy.

Three parameters apply to both configurations:

1. The mount must accept monitors up to 24″ with a standard VESA fitting (75×75 or 100×100 mm, MIS-D)
2. The screen’s range of adjustment, in height and tilt, must suit standing use by operators of differing heights;
3. The housing compartment for a mini PC, thin client or laptop must be lockable with an anti-theft lock, to protect devices that on their own represent a significant share of the investment.

A final point on sizing the computing unit: in many healthcare organisations the electronic-health-record client runs in a virtualised environment; in these cases a thin client is enough and shifts the selection criterion from the processor to connectivity and thermal management. This is something the evaluator should ask their own IT function before defining the hardware specifications, not after.

Ergonomics and safety: the criteria you notice only when they are missing

A computer cart is pushed, braked, turned and repositioned dozens of times per shift, often with one hand while the other holds something.
Ergonomic criteria are not finishing touches: they determine whether the equipment will be used as intended or left abandoned against a corridor wall.

The main ones our experience has taught us to attend to:

• The height adjustment of the work surface must cover standing use by operators of differing heights
• The footprint must be contained, with no excessive protrusions that could be a trip hazard for staff and awkward when moving the cart between corridors, room entrances, lifts and so on
• The wheels must combine smooth running on ward floors with a reliable braking system
• The base must ensure stability and resistance to tipping even when fully loaded and during manoeuvres, with the heaviest components (power supply, battery) placed low to lower the centre of gravity
• The total weight when fully loaded must remain manageable by a single operator;
  surfaces must be compatible with the cleaning protocols in use, with no joints that trap dirt
• Cable routing must be tidy and protected, because an exposed cable on the ward is both a trip risk and a point of failure

On the safety side, care must be taken that the compartment for the computing devices can be secured by locking the drawers and compartments: there are various options, from seals to electronic locks, to be chosen according to what the cart carries and the facility’s internal protocols.

Frequently asked questions

To fix the key points, we draw on the most common questions asked on these topics, trying to give the right answer in a few lines.

What is a computer cart?
It is a cart that combines battery power, a mount for the computing device and a work surface, and brings the electronic health record to the patient’s bedside during the ward round and medication distribution. In the international literature it is known as a computer on wheels (COW) or workstation on wheels (WOW).

How much runtime should a computer cart’s battery have?
The operational benchmark is the full length of a shift under variable load, with the monitor on and the PC in continuous use: at least 6 hours under these conditions. The runtime declared at constant laboratory load is generally higher than the real ward figure.

Integrated cart battery or hot-swap batteries?
It depends on the usage pattern, and the comparison is not technological but one of management cost. Hot-swap batteries, usually housed in all-in-one computers, avoid any downtime of the workstation because they are replaced without switching it off, but they must be managed like a fleet: daily checks of charge state, charging stations and charged stocks per ward, with non-negligible per-battery costs. The integrated cart battery recharges by plugging it into the socket and requires no daily management, but it must go back on charge when runtime runs out. For use concentrated within the shift with recharging in the breaks, the integrated battery is generally the simpler and cheaper option; for continuous use around the clock with no recharge windows, hot-swap reduces downtime.

Can a cart already in use be computerized?
Yes, through retrofitting: a module that adds a battery, a mount for a mini PC and a VESA fitting for the monitor to carts already bought. Compatibility must be checked with the manufacturer, particularly on heterogeneous fleets or those near the end of their structural life.

A medical all-in-one computer or a monitor with a separate mini PC?
It depends on the context: the medical all-in-one computer reduces cables and bulk but is replaced as a block; the monitor-plus-mini-PC (or thin client) pairing costs less and is upgraded component by component, and is the natural choice where the clinical record runs in a virtualized environment.

What certifications should a healthcare computerized cart have?
Two levels should be kept distinct. For the computing devices used in the patient vicinity the reference is the IEC 60601-1 standard on medical electrical equipment; medical panel PCs are designed for this conformity. Upstream, however, what matters is the classification of the cart or the system itself: depending on the intended use and configuration, it may fall under the medical-device discipline. This is an evolving field, where not all offerings on the market sit at the same level: for this reason it is worth asking the supplier to state explicitly the product’s classification and the applicable conformities, rather than taking them for granted. The precise verification of requirements rests with the facility’s clinical engineering function.