Alternating Pressure Wheelchair Cushions – Multi-Patient Clinical Study

Powered, alternating pressure wheelchair cushions effectiveness on patients who currently have or are at high risk for developing pressure sores.

Date Submitted: January 2, 2009


J. Gregory Jones, MD, Comprehensive Wound Center, Deaconess Medical Center, Spokane, Washington

Eddie M. Lipan, MD, Tempe St. Luke’s Hospital, Tempe, Arizona


Juli Shogan, RN, Wound Solutions, Colbert, Washington


The overall study objective was to gather evidence that utilizing dynamic, alternating pressure wheelchair cushions in wheelchairs can help increase sitting time while also helping to prevent and/or reduce pressure sores.


Conduct a pilot study to demonstrate the effectiveness of the Airpulse PK cushion system, a commercially available alternating pressure wheelchair cushion system designed to help heal and prevent pressure sores even while sitting time is increased.


The two objectives of this study are to

  1. Increase the sitting time of the subjects without them experiencing additional pressure sores.
  2. Reduce the size or facilitate healing of current pressure sores


Increase the sitting time of each of the subjects while measuring current pressure sores to see evidence of healing and inspect skin to see if any new skin breakdown was evident.  Daily sitting logs were kept and skin was inspected on a daily basis.


Seven patients, 5 men and 2 women, ranging in age from 31 to 70 who currently had pressure sores and/or are high risk with a history of pressure sores, flap surgery and/or sitting pain.  The subjects all use a wheelchair for 100% of their mobility and all are at high risk for developing pressure sores.


Aquila Corporation’s Airpulse PK powered, alternating pressure, cushion system.


Patients are in home care with outpatient visits to the medical facility.


Participants started utilizing the Airpulse PK cushion system at various times over an 18 month period.   Each of the seven participants kept daily sitting and skin inspection logs for two months.  The first subject  began the process in May, 2007, and the last subject completed the two month process in October of 2008.


Although the pilot study group was small, three findings were demonstrated:

  1. Subjects were able to sit in their wheelchairs for extended periods of time while their pressure sores continued to heal.
  2. Subjects experienced no new occurrences of pressure sores after beginning to use the Airpulse PK cushion system.
  3. Existing pressure sores improved even though sitting time was increased.

Supporting Documentation

See the attachments for supporting documentation including general physical information for each participant (Attachment A) and specific wound status and sitting chart summaries for each participant (Attachment B).

Note: Daily sitting logs and skin inspection logs were kept on each participant for a two month period.  A summary of those logs is provided in attachment B.  The summary uses an average sitting time at each two week reporting date.  The pressure sore status is reported in this summary as the skin inspection occurred on the exact date. 

General Information for each Participant

Subject A

Male, Age 61, Weight 260

Quadriplegic as a result of a stroke in 1997. He was confined to either his bed or wheelchair. Pressure sore history includes a spinal ulcer in 1997 and a recurrent Stage III pressure sore on his right ischial. Before using the Airpulse PK Subject A had utilized gel and static cushions as well as a home made donut type cushion. Over a two month trial period Subject A was able to continue sitting for 7 to 9 hours per day while his sore showed dramatic improvement.

Subject B

Female, Age 70, Weight 155

Multiple Sclerosis left Subject B confined to a wheelchair in 1975. Pressure sore history includes three pressure sores since 1985 on the right ischial. One sore has not healed since it opened in 1985. Before using the Airpulse PK Subject B had utilized a foam cushion. Subject B went to the wound clinic weekly. Since using the Airpulse PK Subject B is now sitting 14 hours a day and is able to do the things she loves such as playing bingo while her pressure sore is improving. At the end of the study, Subject B’s wound clinic visits had been reduced to every other week.

Subject C

Male, Age 34,Weight 165

Spina Bifida since birth, T-3 T-4 paraplegic. Pressure sore history includes recurrent breakdown on left ischial resulting in hospitalization and flap surgery in the past. Before using the Airpulse PK Subject C had utilized a static air cushion for his manual wheel chair. At the beginning of study subject was confined to bed with healing stage IV pressure sore and unable to work. After utilizing the Airpulse PK for three months the subject was able to return to work full time.

Subject D

Male, Age 33, Weight 230

Broken neck as the result of a diving accident at the age of 18, C-4 C-5 C-6 incomplete quadriplegic. Pressure sore history includes three flap surgeries, debridement, bone infections requiring shaving of the ischial bones, multiple hospitalizations and a total occurrence of 10 pressure sores. Before using the Airpulse PK the subject had utilized static and gel cushions. At the beginning of the two month trial period the subject was sitting for three hours a day and increased his sitting time to eight hours per day while seeing healing of the wounds on the left and right ischial.

Subject E

Male, Age 33, Weight 155

Quadriplegic as the result of a car accident in 1995.  Pressure sore history includes flap surgery on the left ischial in 2002 and has suffered five recurring pressure sores in the same area since. After beginning the study using the Airpulse PK, Subject E was able to increase sitting time from five minutes to two hours over a six month period without increase in size or severity of the sore. The wound epithelized and may require surgery to close.

Subject F

Male, Age 27, Weight 195

Active paraplegic T-5 SCI as the result of a motor vehicle accident in 1999. Pressure sore history includes a total of 35 -40 wounds since injury with 6-8 wounds in 2002, 3 wounds in 2003 and 5 wounds in 2004. Subject F began using the Airpulse PK in November 2007 sitting for 30 minutes a day with a recently healed Stage III on his left ischial, by January 2008 he was sitting for 8 hours a day with no redness or additional wounds.

Subject G

Female, Age 61, Weight 150

Multiple Sclerosis diagnosed in 1990, fixed pelvic obliquity. Subject has been using wheelchair for mobility since 1994.  Subject G has utilized static and gel cushions in the past. Pressure sore history includes history of pressure ulcers on the right ischial and coccyx. Before utilizing the Airpulse PK the subject was only able to sit in one position for 5 minutes due to severe pain which required repositioning every 5 minutes. Subject G was able to sit for longer periods of time with minimal repositioning on the Airpulse PK.

Wound Measurement 4L x 3W x1/2D 2.6L x 2W x .7D

2.2L x 1.8W x .8D

Subject B Start Date Mid Term

End Date



5/29/2008 6/25/2008
Day Sitting Time 8 hours 13.5 hours 14 hours
Wound Measurement 0.3L x 0.2W x 0.1D 0.3L x 0.2W x 0.3D 0.5L x 0.2W x 0.1D
Subject C Start Date Mid Term

End Date

  10/17/2007 12/1/2007 1/15/2008
Day Sitting Time 30 minutes 12 hours 12 hours
Wound Measurement Healed Stage IV No redness Remained healed
Subject D Start Date Mid Term

End Date

  1/11/2008 2/7/2008 2/18/2008
Day Sitting Time 3 hours 8 hours 8 hours
Wound Measurement #1 2.5L x 2.5W 2.5L x 2W 2.5 x 1
Wound Measurement #2 2L x 1.5W Healed .5L x 1W
Subject E Start Date Mid Term

End Date

  5/15/2007 8/1/2007 11/1/2007
Day Sitting Time 5 minutes 1 hour 2 hours
Wound Measurement 1L x 1W x 4D 1L x 1W x 4D Epithelization Occured
Subject F Start Date Mid Term

End Date

  11/2/2007 12/1/2007 1/3/2008
Day Sitting Time 30 minutes 8 hours 8 hours
Wound Measurement Recently healed stage III   Remained healed
Subject G Start Date Mid Term

End Date

  8/2/2007 8/25/2007 9/14/2007
Day Sitting Time 11.5 hours 10 hours 11 hours
Wound Measurement Recently healed stage III   Remained healed

*All wound measurements are in centimeters.

Old data below:

Summary Sitting and Pressure Sore Status Log

Subject A:           
Gender: Male             
Age: 31
Weight: 260

  Start Date Date Date Date Ending
Date 8/7/08 8/21/08 9/7/08 9/21/08 10/10/08
Sitting Time (hrs/day) 6 5 7 8 8
Wound Status 3.5 x 2.5 x .5 2.7 x 2.9 x .8 2.6 x 2.0 x .7 2.3 x 1.7 x .7 wound closed

(Location Right Ischial)

Subject A (Arizona)

Richard Hoskinson, Male, age 31, weighs 260
Medical Condition: stroke 1997 bedbound and wheelchair. uses. powerchair and had been using a roho cushion
Pressure Sore Status: current sore on right ischial
Measures cm l x 3 cm w x  ½ cm deep at start of study 8/7/08

Subject B:           
Gender: Female             
Age: 70
Weight: 155

  Start Date Date Date Date Ending
Date 5/2/08  5/16/08 5/30/08 6/14/08 6/25/08
Sitting Time (hrs/day) 10 12 10 13 13
Wound Status ? ? ? ? wound closed, redness gone

Subject B (Arizona)

Marilyn Sherlock, Female, Age 70, weighs 155
Medical Condition:  MS
Uses manual wheelchair
Pressure Sore Status:

Subject C:           
Gender: Male             
Age: 34
Weight: 165

  Start Date Date Date Date Ending
Date 10/17/07 10/24/07 11/30/07   12/14/07 1/16/08
Sitting Time (hrs/day) 1 6 10 10 12
Wound Status post flap for stage IV 1 stitch rips, Bedrest-4 weeks no problems no problems back to work on time

7 days post flap

Subject C (Spokane)

Brad Trimble, male, 34 years old and weighs 165
Medical Condition: Spina Bifida since birth, paraplegia T3-T4
Uses Manual Chair & works full time
Pressure Sore Status: Post Flap Surgery to repair pressure sore, Stage IV, left ischial

Subject D:           
Gender: Male             
Age: 33
Weight: 230

  Start Date Date Date Date Ending
Date 1/11/08 2/1/08  2/15/08 2/18/08 2/21/08  
Sitting Time (hrs/day) 3 5 7 8 8
Wound Status – Sore 1 2.5 x 2.5 x 3 1.5 x 2 x 1 2.5 x 2  2.5 x 1  4 x 2.5
Wound Status – Sore 2 2.0 x 1.5 x 3 healed 1 x .5 1 x .5 .5 x 1

Subject D (Spokane)

Jason Johnson, male, 33 years old, weighs 230
Medical Condition: Quadriplegic C-4, C-5
Pressure Sore Status: Problems with pressure sores for 10 years, has had three flap surgeries, two current pressure sores, one right ischial and one left ischial, Stage III.
Uses a power wheelchair       

Subject E:           
Gender: Male             
Age: 33
Weight: 155

  Start Date Date Date Date Ending
Date 5/15/07 6/1/07 6/28/07 7/26/07 11/1/07
Sitting Time (mins/day) 12 30 45 1 hr 2 hrs
Wound Status 1.0 x 1.0 x 4.0 1.0 x 1.0 x 4.0 1.0 x 1.0 x 4.0 no problems epithelialization process caused the wound to heal opened down into the hole

Subject E was able to increase sitting time with no further breakdown or damage to skin.

Subject E (Spokane)

Michael Holmdale, male, 33 years old, weighs 155
Medical Condition: Quadriplegic
Uses a Celera tilt Invacare wheelchair?
Pressure Sore Status: current pressure sore on left ischial-Stage III
Flap surgery to repair pressure sore approximately five years ago

Subject F:           
Gender: Male             
Age: ?
Weight: 195

  Start Date Date Date Date Ending
Date 11/3/07 11/17/07   11/30/07  12/15/07 1/3/08
Sitting Time (hrs/day) 45 min 5 6 8
Wound Status healed Stage III skin clear skin clear skin clear skin clear

Subject F (Spokane)

Andrew Gumm, male, age – 27 weighs 195
Medical Condition: Spinal Cord Injury, T-5, Paraplegic
Pressure sore Status: Since his injury, has had multiple pressure wounds per year over past 10 years for a total of 35 to 40 pressure sores
Goal is to continue to sit for extended periods without getting more pressure sores

Subject G:           
Gender: Female             
Age: 61
Weight: 150

  Start Date Date Date Date Ending
Date 8/01/07 8/15/07 8/30/07  9/09/07 9/19/07
Sitting Time (hrs/day) 10 11 10 11 12
Wound Status recently healed, Stage III, right ischial/coccyx no breakdown, less pain no breakdown, less pain no breakdown, less pain no breakdown, minimal pain

Subject G had a recent flap surgery prior to sitting on the Airpulse PK cushion. A surgical repair site is especially vulnerable to being re-injured. This subject was able to sit up to 12 hours per day with no breakdown at the surgical repair site. This subject illustrates the preventative aspects of the Airpulse PK.

Subject G (Spokane)

Patricia Kessel, Female, Age 61 , weighs 150
Medical Condition: Multiple Sclerosis, fixed pelvic obliquity, leans left in chair
Lacks trunk and leg strength and uses power wheelchair
Pressure Sore Status: Has chronic pressure sore in same area near right ischial
Also experiences severe sciatic nerve pain
Has continual skin breakdown when she uses her wheelchair
Resulting in being bedridden for past three months