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The effect of a trunk release maneuver on Peak Pressure Index, trunk displacement and perceived discomfort… Best, Krista L.; Desharnais, Guylaine; Boily, Jeanette; Miller, William C.; Camp, Patricia G. Nov 16, 2012

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RESEARCH ARTICLEThe effect of a trunk releasmmBest et al. BMC Geriatrics 2012, 12:72http://www.biomedcentral.com/1471-2318/12/72sleeping, the hospital bed becomes a place to engage indaily activities, such as eating, reading and socializing.6James Hogg Research Centre, St. Paul’s Hospital, Vancouver, BC, CanadaFull list of author information is available at the end of the articleBackgroundUp to 65% of older Canadians and Americans develop pres-sure ulcers [1], which can lead to pain, fear and anxiety, iso-lation, reduced quality of life, and in some cases death [2,3].The occurrence of pressure ulcers may increase the amountof professional healthcare needed, which may pose signifi-cant financial burden on the healthcare system [4]. Accor-ding to Woodbury and Houghton, the prevalence ofpressure ulcers in Canada is 25% in acute care, 30% in non-acute care, 22% in mixed health-care settings, and 15% incommunity care [5]. Currently there is no Canadian datathat provides a cost analysis for treatment of pressure ulcersin residential facilities, but a Canadian cost estimate for thetreatment of a stage three pressure ulcers in the communitywas approximately $9000 per patient/month [6].A population at particular risk of pressure ulcers is olderadults with complex care needs, who often also have lim-ited mobility and activity tolerance that leads to greaterperiods of time spent in bed. In addition to resting and* Correspondence: pat.camp@hli.ubc.ca5Department of Physical Therapy, University of British Columbia, Vancouver,BC, Canadaprevention of pressure ulcers that may occur as a result oAbstractBackground: Pressure ulcers pose significant negative individual consequences and financial burden on thehealthcare system. Prolonged sitting in High Fowler’s position (HF) is common clinical practice for older adults whospend extended periods of time in bed. While HF aids in digestion and respiration, being placed in a HF mayincrease perceived discomfort and risk of pressure ulcers due to increased pressure magnitude at the sacral andgluteal regions. It is likely that shearing forces could also contribute to risk of pressure ulcers in HF. The purpose ofthis study was to evaluate the effect of a low-tech and time-efficient Trunk Release Manuever (TRM) on sacral andgluteal pressure, trunk displacement and perceived discomfort in ambulatory older adults.Method: A randomized controlled trial was used. We recruited community-living adults who were 60 years of ageand older using posters, newspaper advertisements and word-of-mouth. Participants were randomly allocated toeither the intervention or control group. The intervention group (n = 59) received the TRM, while the control group(n = 58) maintained the standard HF position.Results: The TRM group had significantly lower mean (SD) PPI values post-intervention compared to the controlgroup, 59.6 (30.7) mmHg and 79.9 (36.5) mmHg respectively (p = 0.002). There was also a significant difference intrunk displacement between the TRM and control groups, +3.2 mm and −5.8 mm respectively (p = 0.005). Therewere no significant differences in perceived discomfort between the groups.Conclusion: The TRM was effective for reducing pressure in the sacral and gluteal regions and for releasing thetrunk at the point of contact between the skin and the support surface, but did not have an effect on perceiveddiscomfort. The TRM is a simple method of repositioning which may have important clinical application for thef HF.Pressure Index, trunk dispdiscomfort in older adultFowler’s position: a randoKrista L Best1, Guylaine Desharnais2, Jeanette Boily2, Willia© 2012 Best et al.; licensee BioMed Central LtdCommons Attribution License (http://creativecreproduction in any medium, provided the orOpen Accessse maneuver on Peaklacement and perceivedseated in a highized controlled trialC Miller1,3,4 and Pat G Camp5,6*. This is an Open Access article distributed under the terms of the Creativeommons.org/licenses/by/2.0), which permits unrestricted use, distribution, andiginal work is properly cited.Nursing textbooks and tradition recommend that patientsin bed be positioned in a high Fowler’s position (HF) tooptimize breathing, eating and conversation [7,8]. It is alsorecommended that patients moved into HF position formeals remain seated upright for 30 min afterwards to re-duce the risk of reflux and aspiration [9].HF is defined as a semi-upright position, in which thepatient's head is raised 60 to 90 degrees (Figure 1) [10].Despite the benefits of HF, the repercussions includeincreased feelings of perceived discomfort, and increasedpressure at the sacral and gluteal regions [11]. Pressureover a bony prominence has been identified by the Inter-national Pressure Ulcer Guidelines [12] as a factor in thedevelopment of pressure ulcers, with the degree of riskBest et al. BMC Geriatrics 2012, 12:72 Page 2 of 10http://www.biomedcentral.com/1471-2318/12/72related to magnitude and duration of pressure [7,13,14].The guidelines also state that pressure combined withshear poses a significant risk for the development ofpressure ulcers, which occurs when friction and oppos-ing forces occur at a localised point. Reasoning wouldsuggest that a patient is also at high risk of shearingforces when placed in HF, because the skin over the sa-cral region will be exposed to friction at the point whereit comes in contact with the bed clothes, sheets, andmattress surface, when head of the bed is elevated andgravity exerts a downward pull on the body [15]. Theshearing forces generated when the body is raised intoHF are estimated to be ten times more likely to lead toulcers compared to pressure alone [16]. Pressure ulcersoccur if pressure and shearing are not alleviated, whichis common in people who do not have the ability to in-dependently reposition their body [17]. Interventionsaimed at repositioning may offer a cost-effective andlow-tech solution to reducing risk of pressure ulcers infrail older adults.The impetus for this study arose when study investigators(GD, JB) noted that residents in a long-term care facilityoften expressed verbal and non-verbal manifestations ofFigure 1 Older adult sitting in a high Fowler’s position.discomfort or refusal to be placed in HF. Clinical observa-tions suggested that passive repositioning of the trunk im-mediately reduced discomfort and interface pressure at thesacral region, which lead to the development of a novel andlow-tech Trunk Release Maneuver (TRM) to reposition thetrunk while sitting in HF.Our primary objective was to test the hypothesis thatthe TRM would significantly decrease pressure at the sa-cral and gluteal regions in older adults. Secondarily, weevaluated the effect of the TRM on trunk displacement(a proxy measure for shear) and perceived discomfort.MethodsStudy designWe conducted a randomized, controlled, single blindtrial at a long term complex care facility in Vancouver,Canada. Recruitment occurred over a 13 month period(March 2010-April 2011). This RCT was registered withClinicalTrials.gov (ID NCT00961012, Unique ProtocolID H09-10370) and was approved by the University ofBritish Columbia Clinical Research Ethics Board and theVancouver Coastal Health Research Institute. Participantconsent to photography was obtained for all figuresincluded in this manuscript.ParticipantsDue to the novelty of the TRM intervention and our clinicalperception that HF places individuals with complex careneeds at increased risk of pressure ulcers, we recruited asample of ambulatory older adults who would be less atrisk. A convenience sample of community-living olderadults was recruited using posters and advertisements insenior-oriented residential buildings, community centers,seniors’ fitness centers, and local newspapers. Word-of-mouth and snowballing techniques were also utilized.Participants were eligible for the study if they: were60 years of age or older; able to speak English; able togive informed consent to participate; and had a FolsteinMini-Mental State Exam (MMSE) [18] score of 22 orhigher [19], indicating that basic cognitive abilities wereunimpaired. Participants were excluded from the study ifthey were at moderate to high risk for pressure ulcers,as determined by a score of 14 or less on the BradenScale for Predicting Pressure Sore Risk.Sociodemographic and personal information (age, sex,marital status, education, place of residence) and health-related variables (body mass index, MMSE, FunctionalComorbidity Index, and the Braden Scale for PredictingPressure Sore Risk) were collected at baseline prior torandomization. The Functional Comorbidity index is an18-item list of diagnoses that uses a simple count (yes/no) to derive a score between 0 and 18, where 0 repre-sents no comorbid illness and 18 represents the highestnumber of comorbid illnesses [20]. The Braden scale is asquare that was fit with a spirit level to ensure consistentplacement of the apparatus on the top of the mattress asshown in Figure 2. After being placed in HF, the testerplaced the square-end of the height gauge across the flatpart of the mattress and measured displacement to thetop of the shoulder in millimetres (mm) to obtain a refer-ence value for trunk position. A positive trunk displace-ment relative to the reference value indicated that thetrunk had moved downward on the mattress surface. Anegative trunk displacement suggested that the trunk hadmoved upward on the mattress surface relative to thereference value, suggesting that the frictional relationshipbetween the trunk and mattress may have been reset. Aresetting of the frictional relationship between the trunkand mattress is believed to be associated with a reductionin the amount of shear that may occur at the point wherethe skin contacts the mattress.We also measured perceived discomfort using either:1. a horizontal numeric scale (ranging from 0–10 inincrements of 1) with word anchors (ranging from noBest et al. BMC Geriatrics 2012, 12:72 Page 3 of 10http://www.biomedcentral.com/1471-2318/12/72pressure ulcer risk assessment scale comprising 6 sub-scales. All subscales are ranked numerically from 1–4,except one that is ranked from 1–3. A summary score isderived by summing up the responses with scores ran-ging from 6–23. Lower scores indicate higher risk forpressure ulcer [21].RandomizationParticipants were randomly allocated to either the inter-vention (TRM) or control group. The randomization se-quence was developed using a computer generated tableof random numbers by a biostatistician who was notassociated with the study. Group allocation was con-cealed using individual sealed opaque envelopes thatwere numbered in sequential order. As individuals wereenrolled in the study the next envelope in the sequencewas extracted and the participant was assigned to theTRM or control group accordingly.MeasurementThe primary outcome measure was interface pressure,measured as the Peak Pressure Index (PPI) in mmHg.Interface pressure was collected using an FSA torsopressure mapping system (Vista Medical, Winnipeg,Canada), which consisted of a sensing mat that was con-nected to an interface box, which relayed the informa-tion to a computer for real-time visualization andrecording [22]. The FSA system is designed tocharacterize the magnitude and distribution of forces viathe use of multiple sensels. The sensing mat was cali-brated weekly using a standardized calibration devicethat consisted of 2 wooden platforms and an air bladderthat can be inflated to a specified pressure. The sensingmat was calibrated to measure pressures between 0 to200 mmHg. PPI was calculated by averaging the senselwith the highest pressure and the 3 surrounding senselswith the highest pressure according to the methodsdescribed by Sprigle, et al. [23]. PPI has been reported tobe the most consistent measure of pressure magnitude[24], has excellent reliability [25], and is supported as anacceptable measure of pressure by the InternationalStandards Organization (ISO) [26].Secondary outcomes measured included trunk displace-ment (a proxy measure for shear), which was used tomeasure whether the trunk had moved in relation to thesurface of the mattress from the time of being placed inHF to after the intervention period. Changes in trunk dis-placement were used to determine whether the interven-tion could reset the relationship between the surface ofthe mattress and the trunk. Trunk displacement, definedas the change in the distance between the top edge of themattress to the top of the participants’ shoulder (at theacromion process), was quantified using a height gauge[15]. The height gauge was comprised of a combinationdiscomfort to very much discomfort) or; 2. the Wong-Baker Faces scale, which consists of 6 faces displayingemotions that range from very sad to very happy and anumeric equivalent ranges from 0–10 in increments of 2[27]. Participants were given the choice to use either thenumeric scale or the Wong Baker scale, depending ontheir preference. Location of discomfort was obtained byasking the participants to point to a diagram of an out-line of an anterior and posterior view of the humanbody. The specific areas where the participant felt dis-comfort were circled by the researcher on the diagram.Figure 2 Trunk displacement was evaluated using a heightgauge to measure the distance from the top of the mattress tothe top of the shoulder.about the intervention period when RA2 re-entered theusing ANCOVA, to control for group differences atBest et al. BMC Geriatrics 2012, 12:72 Page 4 of 10http://www.biomedcentral.com/1471-2318/12/72Participants were told to choose all regions of the bodyin which they felt discomfort.ProtocolTwo research assistants (RA1 and RA2) were trained bya study investigator. Each RA completed about 2 h oftraining on equipment set-up, screening procedures,data collection and administration of the intervention.The study investigator monitored procedures for thefirst 4 participants and did random checks thereafter toinsure fidelity.Data were collected in one 45–60 min session. RA1screened subjects and obtained demographic information,self-reported Braden Pressure Ulcer Risk scores, andFunctional Co-Morbidity Index from each participant.RA2, who was blind to group allocation, recorded per-sonal information (height, weight, age, sex), and collecteddata for interface pressure (PPI), trunk displacement, andperceived magnitude and location of discomfort.The study was conducted using a hospital bed that wasfitted with a visco-elastic foam mattress, a fitted sheet, theFSA torso sensing mat positioned sideways under the par-ticipants’ buttocks, a thin protective plastic layer, a flatsheet and a pillow. All participants wore hospital pyjamasover their undergarments. Participants were then invitedby RA1 to lay supine on the hospital bed with their pelviscentered on the sensing mat and with their hands restingon their abdomen. RA2 ensured proper placement of thepelvis on the sensing mat through real-time visualizationprovided on a computer. Adjustments to positioning weremade as necessary. The participants were coached by RA1throughout the study to remain completely immobile forthe duration of data collection.Once the participant was properly positioned in thebed, RA2 took one baseline measure of perceived magni-tude and location of discomfort while the participantwas lying supine. RA1 then placed the participant in HFby raising the foot of the bed first to its highest position(approximately 50 degrees) followed by the head of thebed to its highest position (approximately 60 degrees).The same hospital bed was used for all subjects. RA2immediately measured trunk displacement and perceivedmagnitude and location of discomfort. After a waitperiod of 8 min, RA 2 recorded 3 consecutive pressuremap images. The 8 min wait period was to allow for“creep” in the FSA pressure sensing mat and mattress.At this point RA 2 left the testing area for 3 min.Group allocation was determined after enrolment intothe study by RA1, who opened the sealed opaque envel-opes in sequence. Participants who were allocated to theintervention group underwent the TRM, while partici-pants in the control group were coached to remain still.After the 3 min intervention or control period, RA2returned to the testing area and immediately measuredbaseline in Functional Comorbidity Index. Within-subjects changes were analyzed using paired-t-tests.Bonferroni corrections were made to account for mul-tiple comparisons using an adjusted alpha of 0.017(0.05/3). As there was a significant difference betweenstudy groups in the numbers of comorbidities, all com-data collection area.Statistical analysisDescriptive statistics (mean, standard deviation, fre-quency) were calculated for all sociodemographic andpersonal characteristics. Differences for all variables atbaseline between the intervention and control groupswere analyzed using unpaired t-tests. Complete datawere obtained for all participants who completed base-line measures; therefore, intention-to-treat analyses werenot necessary. The primary objective to evaluate the ef-fect of TRM on PPI was analyzed using Analysis of Co-variance (ANCOVA), to control for differences betweenthe groups at baseline in Functional Comorbidity Index.Within-subjects changes over time were analyzed usingpaired t-tests and relative change scores were calculatedfor both groups. Similarly, the secondary objectives (toevaluate the effect of TRM on change in trunk displace-ment and change in perceived discomfort) were analyzedtrunk displacement and perceived magnitude and loca-tion of discomfort in both the TRM and control group.All participants stayed in HF for an additional 8 min‘creep’ period before RA2 took the final 3 consecutivepressure map images.Intervention - The Trunk Release Maneuver (TRM)The Trunk Release Maneuver (TRM) was developed by2 of the study investigators with the assistance of theMusculo-Skeletal Injury Prevention (MSIP) team at Van-couver Coastal Health (Figure 3).The TRM is a standardized protocol that consists ofpulling the trunk forward and away from the supportsurface of the bed without lifting the buttocks. Thetrunk can be pulled forward using either a positioningsling or a slider sheet. The trunk release can be per-formed by 1 or 2 attendants, as explained in Figure 3.For the purposes of this study the TRM was performedby 2 people (RA1 and GD) as shown in Figure 4.Control - Participants in the control group did not re-ceive any intervention. They remained positioned in HFposition and were coached not to move by RA1.Participants in both groups were coached not to speakparisons were adjusted for this covariate. All data wereanalyzed using IBM SPSS Statistics version 19.0. MANEUVER (TRM)KEY POINTSPreferable to have two caregivers.TRM cannot be used with a patient who has had a recent hip replacement or rib fractures.KEY POINTSPatients who require assistance to perform a trunk release will also require assistance with other repositioning and therefore should have a repositioning sling (if ceiling lift available) or low friction sliding sheet under them at all times.KEY POINTSCommunication increases cooperation.Even if patient is only able to assist minimally, having the bedrails up may allow them to participate and reduce the force required by the caregiver.Best et al. BMC Geriatrics 2012, 12:72 Page 5 of 10http://www.biomedcentral.com/1471-2318/12/72TRUNK RELEASEUSE WHENCare plans require the *patient to remain in bed, sitting upright.Patient cannot assist to sit up or reposition them self in bed.EQUIPMENT REQUIREDRepositioning slings (if already under patient) AND any one of: transfer belt, band sling, sliding sheet, or flat sheet.PREPARATIONExplain the procedure to the patient and tell them what they can do to assist: lean forward and pull self up with bedrails, as able.Put bedrails up and ensure bed brakes are locked.To position the patient/client/resident in a high-sitting position, raise the foot of the Power calculationWe required a minimum sample size of 120 subjects forthis study. Due to the novel nature of this study therewere no data on effect size or variance to permit a poweranalysis for any of the dependent variables of interest. Tocompensate for this we took 15 measurements of peakpressure index (PPI) from a single subject (Table 1).Given the lowest possible difference in the range ofscores (64 mmHg before and 59 mmHg after trunk re-lease) we anticipated a conservative effect size of 0.6(expected difference/pooled standard deviation (SD)=5 mmHg/8). Using an alpha of 0.01 and power of 0.80 werequired 60 subjects per group for a two sided analyses[28]. A sample of this size also enabled us to detect a twounit difference [27] in discomfort (pooled SD of 2; alphaof 0.01; power 0.9). Trunk displacement is an exploratoryconstruct with no similar known previous measurementdata. Based on our pilot work a 4 cm displacement wasachievable and with a pooled SD of 3 we required 34bed first and then the head of the bed, to the intended position.If the patient is on a repositioning sling, walk from one side of the bed around to the other to feed the transfer belt/band sling/sliding sheet or flat sheet through the end loops of the repositioning sling straps positioned behind the patient’s upper back and shoulders.PROCEDURE KEY POINTSStand at the foot of the bed, facing the patient/client/resident.Grasping both ends of the transfer belt/band sling/sliding sheet or flat sheet with the hands in a neutral or “palm-up” grasp, use a weight shift (from front leg to back leg) to pull the patient forward in bed, releasing their trunk from the mattress. Make the patient comfortable and adjust the bedrails as needed.Using a neutral or palm-up grasp encourages the caregiver to keep their elbows tucked in, protecting the shoulders.Weight shift ensures that thigh muscles are used, rather than the upper body or back.If the head of the bed is raised again after the trunk release has been completed, this procedure must be repeated to ensure reduction in shearing forces against the patient/client/resident.* The term patient may be applied to a patient, client, or resident depending on context used.Figure 3 Description of the Trunk Release Maneuver.Figure 4 TRM being performed by 2 attendants.subjects (17 per group) to reject the Null Hypothesisgiven an alpha of 0.01 and power of 0.8.ResultsStudy sampleFigure 5 depicts the passage of participants throughoutthe study procedures (enrolment, intervention alloca-cognitively high functioning with a Mini Mental StateExam score of 29.3 (1.1). Group equivalence wasachieved on all sociodemographic and personal variablesexcept the intervention group had a significantly highernumber of comorbidities [Functional Comorbidity Index= 2.5 (1.8)] compared to the control group [FunctionalComorbidity Index = 1.8 (1.3)]. Sociodemographic andTable 1 Peak pressure index (PPI) before and after trunk release*Peak Pressure Index (PPI) Before trunk release After trunk releaseRange 64 to 98.75 mmHg 39.5 to 59 mmHgMedian 85.3 mmHg 52.3 mmHg*These results are from a preliminary pressure mapping study that explored the influence of bed linen layers on interface pressure. High pressure over the sacral-coccygeal area was recorded when the person was moved into high Fowler’s position. The procedure was repeated 15 times with different bed linen layers.n=17)Best et al. BMC Geriatrics 2012, 12:72 Page 6 of 10http://www.biomedcentral.com/1471-2318/12/72tion, follow-up, and data analysis) as per the Consoli-dated Standards of Reporting Trials (CONSORT)statement (http://www.consort-statement.org). A total of129 participants were enrolled into the study. Two parti-cipants were excluded from the study because one didnot meet the inclusion criteria and one experienced un-bearable neck pain due to an existing injury when placedin HF. A total of 127 participants were randomized intothe TRM (n = 64) or the control (n = 63) group. Due toequipment malfunction with the pressure map, data for5 participants from each group were excluded from theanalysis. Complete data were obtained and analyzed fora total of 117 participants, (TRM= 59 and control = 58).Sociodemographic and personal informationThe participants in this study ranged in age from 60–88 years, with a mean (standard deviation (SD) age of67.4 (6.7) years. The sample was comprised of predom-inantly single (65%), females (62%) participants, of whom96% were educated at the post-secondary level (Table 1).The participants were physically healthy, with a mean(SD) Body Mass Index (BMI) of 24.8 (4.5) kg/m2; Func-tional Comorbidity Index of 2.2 (1.6), and wereAssessed for eligibility (Randomized (n=12Allocated to TRM (n=64) ALost to follow-up (n= 0)Equipment error (n= 5) LosEquAnalysed (n= 59)Figure 5 CONSORT diagram of progress through the enrolment, interpersonal information are summarized in Table 2.Peak Pressure Index (PPI)There were no significant differences in mean (SD) PPIvalues between the TRM and control groups at baseline,71.3 (37.8) mmHg and 76.8 (35.5) mmHg respectively.The TRM group had significantly lower mean (SD) PPIvalues post-intervention compared to the control group,59.6 (30.7) mmHg and 79.9 (36.5) mmHg respectively [F(1,114) = 9.76, 95% CI = 7.32, 32.67, p = 0.002].Within-subject analysis showed the mean (SD) PPI wassignificantly reduced by 11.7 (16.2) mmHg in the TRMgroup from baseline to post-intervention [p < 0.001, 95%CI = −15.9, -7.5]; whereas the control group had a meanincrease in PPI of 3.1 (7.1) mmHg over the same timeperiod [p = 0.002, 95% CI = −4.9, -1.2]. Figure 6 showsbetween-group and within-subjects comparisons of PPIbetween the TRM and control group.Trunk displacementThere was a significant difference in trunk displace-ment between the TRM and control groups post-intervention [p = 0.005, 95% CI = 4.2, 13.7] as seen in29)Excluded (n= 2)Reason - did not meet eligibility criteria (n=1)- was not able to maintain HF (n=1)llocated to control (n=63)t to follow-up (n=0)ipment error (n= 5) Analysed (n= 58)vention allocation, follow-up, and data analysis of this study.Figure 7. After receiving the intervention, the TRMgroup had a mean (SD) negative trunk displacement of3.2 (15.5) mm relative to the supine position. Partici-Perceived discomfortBoth the TRM and control groups reported a significantincrease in perceived discomfort when moved from lyingTable 2 Sociodemographic, personal and health-related variablesParticipant Characteristics Sample Control TRM p-valueDemographics n = 117 n = 58 n = 59Age, y, mean (SD) 67.4 (6.7) 67.4 (6.7) 68.5 (6.3) 0.63Sex, no. (%) 0.11Male 27 (23.1) 17 (29.4) 10 (16.9)Marital Status, no. (%) 0.57Married/Common Law 45 (38.5) 21 (36.2) 24 (40.7)Widowed/Separated/Divorced 44 (37.6) 21 (36.2) 23 (38.0)Single 28 (23.9) 16 (27.6) 12 (20.3)Education, no. (%) 0.40High School (or less) 21 (17.9) 13 (22.4) 8 (13.6)College/Trade School/University 96 (82.1) 45 (77.6) 51 (86.4)Health-Related Variable, mean (SD)BMI (Kg/m^2) 24.8 (4.5) 25.1 (4.3) 25.6 (4.6) 0.23MMSE (/30) 29.3 (1.1) 29.1 (1.3) 29.4 (0.8) 0.01Braden Pressure Ulcer Risk (/23) 22.8 (0.4) 22.9 (0.4) 22.8 (0.4) 0.03Functional Comorbidity Index (/18) 2.2 (1.6) 1.8 (1.3) 2.5 (1.8) *0.04* Significant difference between groups.Best et al. BMC Geriatrics 2012, 12:72 Page 7 of 10http://www.biomedcentral.com/1471-2318/12/72pants in the control group had a mean (SD) positivetrunk displacement of 5.8 (9.0) mm, relative to the su-pine trunk position.Figure 6 Change in peak pressure index (PPI) from baseline to post-insignificant decrease in of 11.7 mmHg compared to the control group whosupine to a high Fowler’s position. However, there wereno significant differences in discomfort between theTRM and control groups while lying supine, immediatelytervention in the TRM and control group. The TRM had asignificantly increased by 3.1 mmHg.enl gBest et al. BMC Geriatrics 2012, 12:72 Page 8 of 10http://www.biomedcentral.com/1471-2318/12/72Figure 7 Change in trunk entrapment from baseline to post-interventrapment differed significantly by 9 mm between the TRM and controafter being placed in a high Fowler’s position, or immedi-ately post intervention.Adverse effectsOne participant had existing neck pain that was exacer-bated by HF. There were no adverse effects of the TRM forthe participants or the researchers who administered it.DiscussionThe results from this study supported our primary hy-pothesis that a novel Trunk Release Maneuver (TRM) toreposition the torso in HF lead to a reduction in interfacepressure at the sacral and gluteal regions. The TRM groupshowed statistically significant reductions in PPI frombaseline to post-intervention compared to the controlgroup who had a statistically significant increase in PPI.Interface pressure mapping is commonly used as a clin-ical tool to monitor potentially concerning areas of highpressure when sitting on various support surfaces, such asmattresses and wheelchair cushions. In combination withadditional considerations, including skin condition, ana-tomical location, age, hydration, and metabolism of the in-dividual, pressure mapping can help identify areas at riskfor pressure ulcers.While there is an association between interface pres-sure and risk of pressure ulcers [13], there is no solidevidence of a clinically significant pressure threshold.Current clinical practice guidelines suggest that effortstion in the TRM and control group. The amount of trunkroups.be made to reduce the duration and magnitude of pres-sure on areas of the skin that are in contact with a sup-port surface [29]. Although we are not certain of aclinically significant pressure threshold, it is promisingthat participants in the intervention group had statisti-cally significant reduction of 15 mmHg in mean PPI thesacral and gluteal regions after receiving the TRM com-pared to the control group who had a statistically signifi-cant increase in mean PPI. Since bony locations on thebody are more prone to pressure ulcers [30], even slightreductions in pressure at the sacrum and ischial tuberos-ities may have clinical implications. Furthermore, reliev-ing pressure magnitude at areas where shear force ispresent is even more important to reducing risk of pres-sure ulcers because pressure magnitudes that increaserisk of pressure ulcers are almost half of that when littleto no shear is present [31,32]. More research is neededto establish pressure thresholds and to determine clinic-ally significant pressure reductions.Previous studies provide support for interventions thatreposition the body while lying in bed to reduce pressuremagnitude [13,33,34]. A recent Cochrane Review statedthat repositioning of the body is internationally recog-nized and promoted as an integral component of effect-ive pressure ulcer management [35], especially forindividuals who are unable to move themselves. Despiteclinical recommendations and research findings thatsupport the use of repositioning for the prevention ofBest et al. BMC Geriatrics 2012, 12:72 Page 9 of 10http://www.biomedcentral.com/1471-2318/12/72pressure ulcers, the optimal technique has not beendetermined [13,36]. The limited documentations on op-timal repositioning techniques combined with clinicalconcern for the development of pressure ulcers in olderadults who are not capable of independent repositioninglead to the development of the TRM. However, the exactmechanism behind the TRM and pressure reduction atthe sacral and gluteal regions is not clear. It is thoughtto be a combination of the simple repositioning in thebed to redistribute pressure from the sacral and glutealarea to the entire torso, in addition to a release of thetrunk from the frictional forces that occur where theskin over the sacral area contacts the support surface.The notion of a release of the trunk from the frictionthat occurs where the sacrum and low back contact thesupport surface was supported by our findings that par-ticipants in the TRM group had negative trunk displace-ment after the intervention compared to participants inthe control group who showed positive trunk displace-ment. It was thought that if the TRM was successful inresetting the frictional relationship at the point wherethe skin and mattress were in contact at the sacral re-gion, the trunk would be released from the frictionalforces and the individual would be sitting higher in thebed. Although we did not have a direct measure of shear,there is reason to believe that a positive trunk displace-ment would indicate more risk of shear at the pointwhere the skin contacts mattress as a result of frictionand opposing forces between the elevation of the bedand gravity acting on the body. If this is true and shearoccurs at the specific point of contact, the resultantforces are 10 times more destructive to the skin thanpressure alone [16]. Recognizing the limitations to ourcrude proxy measure for shear, shearing forces pose amajor risk factor for pressure ulcers and have not beenquantified in a clinical setting in the literature to date.Surprisingly, there were no differences between theTRM and control groups for level of perceived discom-fort. While some participants in the intervention groupreported an improvement in discomfort after the TRM,other participants did not. This finding was similar forthe control group. Participants in this study were gener-ally healthy with a good BMI and healthy muscle mass.It is possible that a healthy muscle mass may contributeto the decreases sensation of discomfort overtime. An-other possible reason for the lack of difference in per-ceived discomfort between the TRM and control groupswas the use of a generic pain scale to quantify discom-fort. Interestingly, although asked specifically about dis-comfort, many participants used the term pain whenasked to rate their discomfort. Discomfort and pain aredifferent constructs and pain measures may not havecaptured the more diffuse symptoms of discomfort thatour participants experienced. It is possible that perceivedcomfort may have been a more suitable and responsivemeasure for this study. More research in this area isneeded to differentiate these constructs.The limitations of our study include the generalizabilityof our findings from a healthy population who did nothave the complex care needs and health disparities thatare often present in older adults in long-term care. How-ever, we still observed a difference in PPI between theTRM and control groups. Given that our participantslikely had a healthier muscle mass than what would beobserved in residents of long-term care facilities, it isplausible that even greater differences in PPI would beobserved in a more vulnerable population. The challengein determining the location of PPI should also be noted.Due to measurement of PPI on an FSA torso mat, the lo-cation of PPI could be located anywhere over the area ofcontact. Moreover, the location of PPI may change be-tween laying supine and being positioned in HF, or afterperforming TRM. Future studies on the TRM should con-sider palpation or other techniques to determine locationof PPI.The measurement limitations in our study included acrude indicator of trunk entrapment to capture displace-ment of the trunk. Although our measurement device wasfitted with a square-gauge and level to level to increasesconsistency, the reliability and validity of this measure wasnot determined. The premise for measuring trunk entrap-ment came about as a proxy measure for shear. However, aprecise measure of shear is needed to make any conclusionabout the effect of TRM on the reduction of shearing forces.Other limitations arose from our inability to ensure our par-ticipants remained completely still. Although participantswere coached not to move, they were often observed mak-ing small movements of the limbs which may have influ-enced pressure and trunk entrapment measurements.Finally, we did not continue to measure pressure readingsover several hours. It is unknown if prolonged sitting timein HF will negate the benefits of performing the TRM. How-ever, it is known that prolonged sitting in an upright pos-ition is not advisable from a pressure ulcer prevention pointof view. Therefore, it is suspected that frequent repositioningaccording to the TRM protocol would be necessary to re-duce the risk of pressure ulcers.ConclusionsPlacing healthy older adults in HF causes concerningpressure magnitudes over the sacral and gluteal regions.A novel, simple, and time efficient Trunk Release Man-euver to reposition the body reduces interface pressureand trunk displacement in the short term, but does notreduce perceived discomfort.Competing interestsNone of the authors have competing interests to report.1. Kaltenthaler E, Whitfield MD, et al: UK, USA and Canada: how do their10. Mosby, Inc: Mosby's Dictionary of Medicine, Nursing and Health Professions.14. Sprigle S, Sonenblum S: Assessing evidence supporting redistribution ofpressure for pressure ulcer prevention. JRRD 2011, 48(3):203–214.15. Fontaine R, Risley S, Castellino R: A quantitative analysis of pressure andshear in the effectiveness of support surfaces. J Wound OstomyBest et al. BMC Geriatrics 2012, 12:72 Page 10 of 10http://www.biomedcentral.com/1471-2318/12/728th edition. St. Louis, MO: Mosby/Elsevier; 2009.11. Best KL, Desharnais G, Boily J, Camp PG, Miller WC: An exploration ofperceived discomfort and pressure in older adults sitting up in bed. InProceedings from the 40th Annual Scientific and Educational Meeting of theCanadian Association on Gerontology, New Directions for Aging; 21–23October. Ottawa, ON: 2011.12. European Pressure Ulcer Advisory Panel and National Pressure UlcerAdvisory Panel: Prevention and treatment of pressure ulcers: quick referenceguide. Washington DC: National Pressure Ulcer Advisory Panel; 2009.pressure ulcer prevalence and incidence data compare? J Wound Care2001, 10(1):530–535.2. Fox C: Living with a pressure ulcer: a descriptive study of patients’experiences. Br J Comm Nurs – Wound Care Supplement 2002, 10:12–14.3. Hopkins A, Dealey C, et al: Patient stories of living with a pressureulcer. J Adv Nurs 2006, 56(4):345–353.4. Theisen S, Drabik A, Stock S: Pressure ulcers in older hospitalisedpatients and its impact on length of stay: a retrospectiveobservational study. J Clin Nurs 2012, 21(3/4):380–387.5. Woodbury MG, Houghton PE: Prevalence of pressure ulcers in Canadianhealthcare settings. Ostomy Wound Manage, 50(10):22–38. [serial online]2004 Oct [cited 2009 Feb 27]; Available from: URL: www.cawc.net.6. Allan J, Houghton P: A case study for electrical stimulation on a stagethree pressure ulcer. Wound Care Canada [serial online] 2004, 2(1):34–36.7. Metzler DJ, Harr J: Positioning your patient properly. Am J Nurs 1996,96(3):33–37.8. Burns SM, Egloff MB, Ryan B, Carpenter R, Burns JE: Effect of bodyposition on spontaneous respiratory rate and tidal volume in patientswith obesity, abdominal distention and ascites. Am J Crit Care 1994,3(2):102–106.9. O’Sullivan N, Godfrey M, van Boldrik A, Puntil J: Dysphagia care teamapproach with acute and long term patients. 1st edition. Los Angeles, CA:Cottage Square; 1990.Authors’ contributionsAll authors read and approved the final version of the manuscript. GD andJB conceived the project and developed the intervention. GD, JB, WM andPC developed the study hypotheses, protocol and wrote the grant to obtainfunds for the project and assisted with interpretation of the findings. KBconducted the statistical analysis under the supervision of WM and PC. KBdrafted the manuscript under the supervision of PC. KB provided assistancewith collecting the study data.AcknowledgementThis project was funded through a Team Grant from Vancouver CoastalHealth Research Institute.We would like to thank Suzanna Huebsch for her persistent effort with therecruitment of participants and the coordination of all testing sessions. Ms.Best is a Vanier Canada Graduate Scholar. Dr. Miller is a Canadian Institutesfor Health Research Investigator. Dr. Camp is a Michael Smith Foundation forHealth Research Scholar. Also, we would like to acknowledge the support ofSharon Galloway, Banfield Pavilion Resident Services Manager.Author details1Rehabilitation Sciences Graduate Program, University of British Columbia,T325 - 2211 Wesbrook Mall, Vancouver, BC V6T 2B5, Canada. 2BanfieldPavilion, Vancouver Coastal Health, Ash Street, Vancouver, BC, Canada. 3G FStrong Rehabilitation Centre, 4255 Laurel Street, Vancouver, BC, Canada.4Department of Occupational Science and Occupational Therapy, Universityof British Columbia, Vancouver, BC, Canada. 5Department of Physical Therapy,University of British Columbia, Vancouver, BC, Canada. 6James Hogg ResearchCentre, St. Paul’s Hospital, Vancouver, BC, Canada.Received: 10 April 2012 Accepted: 9 November 2012Published: 16 November 2012References13. Peterson MME, Schwab W, McCutcheon K, Van Oostrom JH, Gravenstein N,Caruso L: Effects of elevating the head of bed on interface pressure involunteers. 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Winnipeg, Manitoba: Vista Medical Ltd; http://www.pressuremapping.com.23. Hanson D, Thompson P, Langemo D, Hunter S, Anderson J: Pressuremapping. A new path to pressure ulcer prevention. American Nurse Today2007, 2(11):10–12.24. Sprigle S, Dunlop W, Press L: Reliability of bench tests of interfacepressure. Assist Technol 2003, 15(1):49–57.25. Romeo M, Swaine J, Nguyen V, Stacey M, Wound Healing and OccupationalPerformance Research Group: The reliability of post processing metrics forinterface pressure mapping. In Proceedings from the 28th InternationalSeating Symposium. 7-9 March. Vancouver, BC; 2012.26. International Organization for Standardization; Available: http://www.iso.org/iso/home.27. McCaffery M, Pasero C: Pain clinical manual. 2nd edition. St. Louis, MO:Mosby; 1999.28. Portney LG, Watkins MP: Foundations of Clinical Research: Applications toPractice. Upper Saddle River, NJ: Prentice Hall Health; 2000.29. European Pressure Ulcer Advisory Panel and National Pressure UlcerAdvisory Panel: Prevention and Treatment of Pressure Ulcers: Quick ReferenceGuide. National Pressure Ulcer Advisory Panel. DC: Washington; 2009.30. Sangeorzan BJ, Harrington RM, Wyss CR, Czerniecki JM, Matsen FA 3rd:Circulatory and mechanical response of skin to loading. J Orthop Res1989, 7(3):425–431.31. Dinsdale SM: Decubitus ulcers in swine: light and electron microscopicstudy of pathogenesis. Arch Phys Med Rehabil 1973, 54:51–56.32. Bennett L, Lee BY: Vertical shear existence in animal pressure thresholdexperiments. Decubitus 1988, 1(1):18–24.33. Peterson ML, Schwab W, van Oostrom JH, Gravenstein N, Caruso LJ: Effectsof turning on skin-bed interface pressure in healthy adults. J Adv Nurs2010, 66(7):1556–1564.34. Sideranko S, Quinn A, Burns k, Froman R: Effects of position and mattressoverlay on sacral and heel pressures in a clinical population. Res NursHealth 1992, 15:245–251.35. Moore Z, Cowman S: Repositioning for treating pressure ulcers. CochraneDatabase Syst Rev 2009, 15(2):CD006898.36. Krapfl LA, Gray M: Does regular repositioning prevent pressure ulcers?J Wound Ostomy Continence Nurs 2008, 35(6):571–577.doi:10.1186/1471-2318-12-72Cite this article as: Best et al.: The effect of a trunk release maneuver onPeak Pressure Index, trunk displacement and perceived discomfort inolder adults seated in a high Fowler’s position: a randomized controlledtrial. BMC Geriatrics 2012 12:72.


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