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The liberation that wheelchairs provide is obvious to most: The ability to sustain mobility in everyday environments. However, what's not so obvious is that for those with very involved disabilities, a wheelchair is only part of the mobility equation, where other medical components must work in conjunction with the wheelchair in order for one to achieve mobility. This fact is especially evident when it comes to respiratory ventilators, and one's understanding of exactly how ventilators interface with wheelchairs is an important move toward optimizing mobility for those with very advanced needs.

A Brief History of Ventilators
The first "negative pressure ventilator" was used in 1928, and quickly adopted the name, Iron Lung. An iron lung was a large, cylindrical chamber that encapsulated a person from the neck down, creating artificial breathing function by decreasing and increasing air pressure within the chamber by moving the lungs of those who were paralyzed. During the 1940s and 1950s, the iron long was at its height of usage, saving the lives of countless individuals paralyzed by polio.

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Ventilator Ward Circa 1950

However, the iron lung was a disturbingly debilitating device. While an iron lung kept one alive, it rendered one entirely immobile, typically confined to a hospital ward, unable to move, encapsulated in a huge machine.

In 1952, the "positive pressure ventilator" was invented, forever improving lives. The new ventilator design was a small, portable pump that forced air into one's lungs via a single breathing tube. Rather than being encapsulated in an iron lung, one could now remain in bed or in one's wheelchair, mobile.

According to CNN, in 2007, only 30 iron lungs remain in use in the United States, with "portable" ventilators now the health care standard. Today, it's common to see ventilators mounted on wheelchairs, with those of complex disabilities leading strikingly liberated lives, from home to office and beyond.

Common Types of Portable Ventilators
The Achieva portable ventilator by Puritan Bennett, has long been the industry standard for ventilator use on wheelchairs. Measuring 10.75"H x 13.30"W x 15.60"D, the Achieva is about the size of a large toaster oven, and weighs 32lbs. In addition to the Achieva, itself, an external battery is used, ranging from a U1 to a 22NF (though, the unit does contain an internal back-up battery for emergency use of up to 4 hours).

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The leading edge of portable ventilator technology is the Pulmonetics LTV series, dramatically reducing the size and weight of ventilator technology. The LTV only weighs approximately 13.5lbs, and is just a scant larger than a notebook computer, measuring 3"H x 10"W x 12"D. What's more, the LTV operates via internal power or an external lithium-ion battery, both of which further dramatically reduce overall size and weight.

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Mounting Portable Ventilators to Wheelchairs
When it comes to mounting ventilators on wheelchairs, manual wheelchairs are the most clear-cut. Used namely on manual wheelchair tilt-in-space models, ventilators sit on a tray underneath the seat, secured to a "vent tray" that houses both the ventilator and the battery. This combination creates a stable - albeit, heavier - manual wheelchair/ventilator combination, where the wheelchair's dimensions do not notably increase.

However, mounting ventilators on power wheelchairs is a much more subjective, consequential proposition. Because all of the space beneath power wheelchair seating is consumed by the power base, itself - batteries, motors, and electronics - the only place to mount a ventilator is on the rear of the power wheelchair. Achieva-type ventilators mount on a rack on the rear of the power wheelchair via a gimbled vent tray that places the ventilator on top, and its U1 or 22NF battery below it. This configuration not only typically increases the power wheelchair's length by 15", but also adds a total of approximately 60 pounds to the very rear of the power wheelchair, affecting overall maneuverability, stability, and performance (and, for these reasons, vent trays are only offered on certain power wheelchair models and seating).

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The compact LTV series of ventilators is unquestionably a far more practical vent to mount, typically adding very little - if any - length to a power wheelchair. Further, because the LTV is so light at 13.5lbs, and is commonly used with its lithium-ion battery technology, it places very little weight on the rear of the power wheelchair, allowing nearly normal handling.

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Optimizing Ventilator Use with Power Wheelchairs
The fact is, when one needs a ventilator, there's no choice but to use it, including with a power wheelchair when required for mobility. However, ventilators installed on power wheelchairs can detract from a power wheelchair's performance, so thought should be given to their installation.

Firstly, the ideal compatibility with a power wheelchair is the LTV series of ventilators, where they're light and compact. However, due to funding constraints and respiratory needs, not everyone qualifies for an LTV ventilator. Therefore, optimizing use of the larger, Achieva-style ventilators is important.

Of major consequence to using an Achieva-style ventilator on a power wheelchair is that the weight placed on the rear of the wheelchair - consisting of the ventilator and its battery, around 60lbs. - can cause "fishtailing" at higher speeds, making the power wheelchair more difficult to steer. Therefore, minimizing a ventilator's weight on the rear of the power wheelchair serves overall performance. This is accomplished on select power wheelchair models that are designed with a battery box in the power base that holds two Group-24 batteries as standard, or three 22NF batteries (two that power the wheelchair, and one that powers the ventilator). As a result, the ventilator's battery, weighing approximately 30lbs., can be repositioned from the rear of the power wheelchair to underneath the seat, in the power base, increasing overall performance, including enhancing tracking and stability.  (Moving from two Group-24 batteries to the three 22NF battery configuration will slightly reduce driving range; however, many users find that being able to place the ventilator battery in the power base, rather than hanging it on the rear of the power wheelchair, notably enhances overall performance - a meaningful trade-off for slightly reduced range.)

Getting It Right from the Start
Whenever possible, an LTV series ventilator is unquestionably the best technology to combine with a wheelchair - light and compact. However, if one uses the more-common Achieva-style ventilator, ordering a power wheelchair with the capacity to hold the ventilator battery within the power base will increase overall wheelchair performance.

When one requires both a wheelchair and a ventilator, considering how to optimally combine the two will optimize one's overall mobility, where a ventilator will compliment one's mobility, not detract from it.

Published 3/09, Copyright 2009,