Ch 12 - Wheelchairs

Question 1

What is a major contributing factor to increased deformity and pressure ulcer development?

Answer 1

Inaccurate measurements during WC seating system measurements

Question 2

How should seat width be measured?

Answer 2

Measure across the widest point of the hips (with clothing and any braces or orthoses)

Question 3

What should the seat width be for manual WC users?

Answer 3

Same as max hip width or up to 1 inch greater than the patient’s measured hip width

Question 4

What should the seat width be for power WC users?

Answer 4

Up to 1 inch wider than their hip width but utilize hip guides to ensure maximum alignment is maintained in the pelvis with scoliosis

Question 5

What are complications of too narrow WC seat widths?

Answer 5

Transfers will be more difficult

Inc risk of pressure ulcer on the greater trochanters

Question 6

What are complications of too wide WC seat widths?

Answer 6

Trunk support is compromised l/t scoliosis, back pain, and difficulty with WC propulsion

Question 7

How is seat depth measured?

Answer 7

Dorsal buttocks to the popliteal fossa, and subtract 1/2 inch from this measurement
Subtract backrest cushion measurement

Question 8

How are seat depth measurements changed for patients propelling WC with feet?

Answer 8

1 to 2 inches subtracted

Cushion is beveled back to allow the knee adequate flexion to propel the wheelchair.

Question 9

What are complications of too shallow WC seat depths?

Answer 9

Dec distribution throughout the femurs, resulting in Inc pressure on the ischial tuberosities

Question 10

How is seat height measured?

Answer 10

Lower leg length from the bottom of the heel of the shoe to the posterior thigh. Subtract the height of the “compressed” seat cushion from the measurement, and then add 3 to 4 inches to allow for adequate leg rest clearance

Question 11

How are seat height measurements changed for foot drive or hemiplegic height WC?

Answer 11

Seat closer to the floor, to allow the unaffected leg to propel the chair

Question 12

Where should WC back rest be in patient’s who use their arms for propulsion?

Answer 12

Inferior angle of the scapula

Question 13

Where should WC back rest be in patient’s who has no UE strength and poor trunk control?

Answer 13

Spine of scapula

Question 14

How is head support for WC measured?

Answer 14

Bottom of the buttocks to the top of the cranium, add the height of the “compressed” seat cushion and adjust down by 2 to 4 inches depending on the patient’s support preference

Question 15

How are armrests for WC measured?

Answer 15

Bottom of the patient’s bent elbow at 90° and add the height of the compressed seat cushion

Question 16

What is the MC prescribed armrest?

Answer 16

Removable desk length armrest Of ~10”

Question 17

How are footrests for WC measured?

Answer 17

Distance from the heel of a patient’s shoe to the posterior surface of the thigh at the popliteal fossa
Footrest at least 2 inch clearance from floor

Question 18

What is the most important reason for tilt and recline seating systems?

Answer 18

Provide patient or caregiver ability to perform adequate weight shift for pressure redistribution to minimize the risk of pressure ulcer and to provide a patient with postural support from gravity for upright

Question 19

What degrees of reclining can be added to a WC?

Answer 19

Semi: 120°
Full: 180°

Question 20

What does a tilt-in space system allow for?

Answer 20

Pressure to be redistributed from the seating surface to the back support

Question 21

What degree of tilt should a tilt-in space system allow to redistribute sufficient pressure?

Answer 21

Tilt at least 45°

Most systems provide 45° to 60° of posterior tilt

Question 22

What are advantages of a tilt-in space system?

Answer 22

– Independent pressure relief
– Postural support from gravity
– Pain relief
– Assist in orthostatic episodes
– Minimizes shear
– Diminishes effects of spasticity during position changes
– Maintains seating position during weight shifts
– Helps mobilize secretions
– Smaller turning radius

Question 23

What are the standard size WC wheels?

Answer 23

3-to 8-inch (diameter) front caster wheels

24-inch (diameter) rear wheels

Question 24

When is a fixed axle appropriate?

Answer 24

Someone who is not using the wheelchair as a primary means of mobility

Question 25

How can an adjustable axle be moved?

Answer 25

Moved forward to position the center of gravity underneath the client to allow for improved rear wheel access and more efficient wheelchair propulsion

Question 26

What does a forward axle position facilitate?

Answer 26

“Wheelies” to transition up/down curbs

Question 27

What does a posterior axle position facilitate?

Answer 27

Inc WC stability to compensate for the change in the location of the COG

Question 28

When is a posterior axle position essential?

Answer 28

Absence of legs in a bilateral amputee patient and with a reclining back or tilt-in-space WC

Question 29

What happens with more posterior rear wheels?

Answer 29

– Inc rolling resistance 
– Inc energy required for propulsion
– Inc turning radius 
– More stable the chair 
– More extension needed at GH joint, which can inc stress/injuries at the shoulder

Question 30

What happens with more anterior rear wheels?

Answer 30

– Dec rolling resistance
– Dec energy required to propel
– Smaller turning radius
– Less stable chair
– More maneuverable (easier to perform a “wheelie”)
– Relieve shoulder pain during manual propulsion

Question 31

What is the best tire for carpet?

Answer 31

Pneumatic tires are best because carpeting increases the rolling resistance by a factor of 4

Question 32

What does WC camber with lower wheel further out than top of wheel allow for?

Answer 32

Better biomechanical location to the shoulder joint
Easier to propel (especially at higher speeds)
Inc stability
Easier to turn

Question 33

What is the camber of everyday WC uses?

Answer 33

2° to 5°

Question 34

Which patients use one-hand-drive WC?

Answer 34

Plexus injury
Upper extremity amputation
Hemiplegia

Question 35

What does a smaller caster allow for?

Answer 35

Smaller turning radius but performs poorly on outdoor surfaces and on carpets because it can get stuck in cracks on sidewalks and in uneven contours of an uneven surface

Question 36

What is the standard castor size?

Answer 36

8-inch diameter on a basic WC

Question 37

What castor size allows for the best overall indoor and outdoor performance?

Answer 37

5 or 6-inch diameter

Question 38

What does moving the castor more posteriorly cause?

Answer 38

Dec turning radius
Inc maneuverability
Dec stability

Question 39

What are the types of WC cushions?

Answer 39

Viscous fluid
Air
Gel
Viscoelastic foam
Foam

Question 40

Describe the controls of a sip and puff WC.

Answer 40

Hard puff: forward
Soft puff: right
Soft sip: left
Hard sip: stop, once the WC is stopped, it can also be a reverse command