| Intelligent Pressure Ulcer Prevention cushion (iPUPc). The uniqueness of our IAPRS system lies in its ability to prevent sustained and elevated pressure, through dynamic changes in sitting posture. More specifically, the back part of the seat (BPS) periodically tilts inferiorly with respect to the front part of the seat (FPS), while lumbar support is enhanced, thereby unloading the ischial tuberosities, which experience the greatest pressure loads of the seated individual. Sitting alternately between the Normal (sitting without BPS adjustment) and WO-BPS (sitting with a lowered BPS and enhanced lumbar support) postures, defined as Alternate sitting,
- Significantly reduced interface pressure on the subject’s buttocks,
- Promoted tissue perfusion
- Decreased skin temperature elevation
- Maintaining functional performance (reaching and propulsion) and comfort for the wheelchair users
- Improved lung capacity
These results confirm that our IAPRS system can have a significant impact in PU prevention for SCI patients.
Mechanism: IAPRS periodically switches wheelchair users’ sitting posture between Normal and WO-BPS.
Finding: IAPRS periodically redistributes the concentrated pressure over the ischia to less vulnerable locations, such as thighs and back 
Figure 1. X Sensor equipment
Figure 2.
Table 1. The Pressure Parameters (mean±SE) for total contact area (TCA), average pressure (AP), and peak pressure (PP) calculated from the Alternate and Normal+Pushups protocols, for the whole seat cushion, and anterior, middle and posterior portions of the seat cushion for Control, Paraplegic, and Quadriplegic subjects. PNA: P value of difference between 2 protocols. A bold font of P indicates a statistical significance. 
Transcutaneous tissue perfusion was used as a measure of tissue viability in our study. 
 
 
(click for Radiometer America homepage) Sitting protocols:
Alternate using IAPRS;
Normal + Pushup: Subject sit in Normal posture doing arm push-up every 20 minutes
Average tissue perfusion level: Average tcPO2 and tcPCO2 for each protocol were determined. 
Tissue Perfusion Primary Change Times: Interface Pressure rises and releases when the subject changed his/her posture. For example, at IT, pressure release occurred when the sitting posture changed from Normal to WO-BPS, and when the subject started to do a Pushup. The primary changing period (PCP), defined as the time the tissue perfusion parameters take to complete 90% of the maximum change, was determined for both tcPO2 and tcPCO2 during the interface pressure rise and release. E.g. during pressure rise, PCP for tcPO2 was the time it drops to10% of its initial high level, while for tcPCO2, it will be the time it reached 90% of its final high level: Average tcPO2 and tcPCO2 for each protocol were determined. 
Publications:
Local Tissue Perfusion Recovery Using an Automated Seating System Featuring Dynamic Ischial Unloading (pdf) Alternating Ischial Support as a Method of Preventing the Instance of Pressure Ulcers (pdf) Skin Temperature was measured from IT. Mid Thigh (MT), and Distal Thigh (DT) during Alternate and Normal+Pushup sitting protocols using thermometers. Finding: skin temperature elevated significantly less while using IAPRS. 
Reaching performance for wheelchair users was investigated during tasks shown in the drawings. Tasks were designed to evaluate the reaching performance through reaching distance, reaching height, and reaching direction. Twelve SCI patients (35.6±9.3yrs; 82.8±14.4kg; 172.1±11.3cm) were tested. Findings: Sitting in WO-BPS posture did not alter wheelchair users’ reaching ability. Compared with Normal posture, sitting in WO-BPS posture did not significantly change the overall reaching performance. 
Publications:
Nathan Coomer, Lance Labno, Michelle Carlevato, Lynnea Pemberton, Jane Quach, Evan McLeod, Fang Lin, Mohsen Makhsous (2006). Reaching Performance Using a New Seat Design in Wheelchair Users with Spinal Cord Injury, RESNA 29th Int. Conference. (pdf) Since the WO-BPS posture changes the center of mass for seated individual, the influence of this posture on manual wheelchair propulsion are under investigation in BOSSM lab for following parameters:
The propelling forces and moment, the speed of the wheel, the stroke frequency, and the travel distance are measured by the SmartWheel. Muscle activity is measure by surface EMG (Delsys) from the upper extremity and trunk muscles. Findings: The project is ongoing. 
We hypothesized that sitting posture affects the respiratory performance of seated individual through the change of the effective space within the ribcage and the efficiency of respiratory muscles. Forced Vital Capacity (FVC), Forced Expiratory Volume in 1second (FEV1), Forced Expiratory Ratio (FER) and Peak Expiratory Flow (PEF) were measured in 40 subjects in the Normal, WO-BPS and Slumped postures. Findings: Slumped sitting significantly decreased LC-EF, The WO-BPS posture significantly promoted LC-EF, The WO-BPS posture might be a better seating option for people sitting for a prolonged time. 
Publications:
Fang Lin, DSc , Sriranjani Parthasarathy, BS , Susan J. Taylor, OT/L , Deborah Pucci, MPT , Ronald W. Hendrix, MD , Mohsen Makhsous, PhD (2006) Effect of Different Sitting Postures on Lung Capacity, Expiratory Flow, and Lumbar Lordosis, Arch PM&R. (pdf) | |
