In hospital settings, where thehead of the bed (HOB) com-monly is elevated, gravity caus-

es patients to slide, or migrate,toward the foot of the bed. Nurs-es are well aware of this, asthey’re regularly required to pullpatients back toward the HOB ifthey can’t reposition themselves.

A 1995 study at one hospitalfound nurses pulled patients up inbed an average of 9.9 times pershift. More recent evidence sug-gests this activity may be evenmore common in some hospitalsand units.Studies show that pulling pa-

tients who’ve migrated in bed

carries an extremely high risk ofcaregiver injury. Less researchhas been done on the effects ofmigration on patients. This articledescribes how migration can af-fect patient outcomes, outlines rel-evant scientific evidence, and dis-cusses strategies for managingpatient migration.

The sliding patient:How to respond toand prevent migrationin bed Migration can cause negative patient outcomes andcaregiver injuries resulting from repositioning. By Neal Wiggermann, PhD

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Negative effects ofmigration A 2013 study found that patientsin traditional hospital-bed designsmigrated about 13 cm (5") whenthe HOB was raised to 45 de-grees. Both bed movement andgravity cause patients to slidedown in bed over time if the HOBis kept elevated. Such migrationpresumably causes friction and

shear forces between the mattressand skin as the patient slidesagainst the bed surface. Althoughfriction and shear have beenlinked to pressure-ulcer formation,no research has evaluated whetherfriction and shear caused by mi-gration directly contribute to pres-sure-ulcer risk. As patients migrate toward the

foot of the bed, the torso eleva-

tion decreases. A pilot investiga-tion of 10 healthy subjects lyingwith the HOB at 30 degreesshowed their torso angle wasabout 30 degrees when properlyaligned with the hip indicator,compared to about 12 degreeswhen they migrated 23 cm (9")past the hip indicator. Positioning the HOB at or

above 30 degrees is intended to reduce the risk of ventilator-associated pneumonia (VAP) be-cause torso elevation decreasesthe risk of aspirating gastric con-tents into the lungs. Once patientshave migrated farther down themattress, elevating the HOB mayno longer reduce aspiration riskbecause their torsos are flatter. Atthat point, if they’re not reposi-tioned, they may be at increasedrisk for VAP. When patients migrate down in

bed with the HOB up, they slideout away from the pivot of theHOB section and the lumbar spinegoes unsupported, causing kypho-sis. Kyphosis reduces lung capaci-ty, so respiratory function may diminish in patients who’ve migrat-ed. Although the relationship be-tween kyphotic postures causedby migration and discomfort has-

n't been studied for hospital beds,it’s reasonable to expect migrationwould result in discomfort, espe-cially in patients with low backpain or disc herniation.

Responding to patientmigration To help prevent negative outcomesassociated with patient migration,be diligent in repositioning pa-tients who’ve migrated downward.But be aware that repositioning ismost likely to affect outcomes relat-ed to torso angle (such as VAP, re-duced lung capacity, and discom-fort)—not friction and shear linkedto pressure-ulcer development.Among patients unable to boost orreposition themselves in bed,those on mechanical ventilatorsand those with back pain may bemost in need of repositioning bythe nurse. Repositioning patients manual-

ly is associated with a high riskof musculoskeletal injury, so al-ways use repositioning aids forpatients unable to repositionthemselves. Using lift equipment,such as a ceiling-mounted or mo-bile lift, is the best way to reducehealthcare worker strain, accord-ing to the American Nurses Asso-ciation’s Safe Patient Handlingand Mobility: InterprofessionalNational Standards, which callsfor eliminating manual lifting inall healthcare settings.If lift equipment isn’t available,

use a friction-reducing sheet andplace the bed in the Trendelenburgposition (if the patient can tolerateit). If the patient is on an air sur-face, use the “max inflate” func-tion. Patients who can provide par-tial assistance should participate inmobilization by placing their feetflat on the mattress and “bridging”when being repositioned. The pa-

18 Current Topics in Safe Patient Handling and Mobility September 2014 www.AmericanNurseToday.com

Considerations when purchasing hospitalbeds Before purchasing hospital beds, clinicians and hospital purchasing staff should evaluate rele-vant manufacturer claims and test data to determine how well the product performs to reducepatient migration. Keep the following points in mind.

• Migration test results may vary based on methodology, so be suspicious of marketingmaterials that don’t describe test methods.

• Consider the relevance of test conditions to their clinical application.

• Be aware that a proper experimental design can improve test result accuracy. For exam-ple, a laboratory motion-capture system produces less error than a tape measure, and alarge subject sample (10 or more) with subjects of varied heights and weights is more ac-curate than a small or homogenous sample.

• Make sure migration is reported with respect to the bed surface. Because the top sectionsof some hospital bed frames can move back relative to the floor, measuring migrationrelative to the floor rather than the bed surface can lead to the mistaken conclusion thata patient has migrated several inches less than he or she actually has.

Once patients have migratedfarther down the mattress,

elevating the HOB may no

longer reduce aspiration risk.

tient also may pull on tractionequipment, a trapeze bar, or thebed side rails, if available. However, be aware that any

method that involves manual liftingcan cause injury to the nurse. Oneresearcher found that based onthe postures adopted when han-dling patients, caregivers who liftwith forces above 16 kg (35 lb)are at increased risk of injury. Themost effective way to prevent self-injury when repositioning patientsis to use a ceiling-mounted or mo-bile lift. An air-assisted lateraltransfer device also can be usedto reposition the patient up in bed.

Preventing migration Despite the impact of migration onpatients and caregivers, little re-search exists on how to prevent it.The bed’s contribution to migrationhas been investigated in laborato-ry studies, but patient movementhas yet to be studied. To limit migration when articu-

lating the bed, use auto-contour (aknee gatch that rises automaticallyand simultaneously as the HOBrises) to reduce migration by up to2.5 cm (1"). If the bed doesn’thave auto-contour, raise the kneegatch before raising the HOB. Be-sides limiting migration from bedarticulation, keeping the patient’sknees raised also may help limitmigration over time. Of course,these strategies can be used onlyif the patient can tolerate kneebending.Design of the bed-frame articu-

lation seems to have an even big-ger effect than auto-contour on theamount of patient migration. Forexample, across three differentbed-frame designs, mean cumula-tive movement (total amount ofsliding when raising and loweringthe HOB) ranged from 13 to 28

cm (5" to 11"). Most likely, migra-tion caused by bed movement willcontinue to decrease as manufac-turers develop beds more compati-ble with the changing geometry ofthe patient as the HOB rises. (SeeConsiderations when purchasinghospital beds.) More research is needed to

confirm indications that patientmigration toward the foot of thebed increases pressure-ulcer andVAP risk, causes patient discom-fort, and reduces lung capacity.Many tools are available to helpnurses safely reposition patientswho’ve migrated. Using auto-contour when raising the HOB orthe knee gatch may help preventmigration or slow its rate. Designof the bed’s articulation also af-fects the distance that a patientmigrates. 8

Selected referencesAmerican Nurses Association. Safe Patient Han-dling and Mobility: Interprofessional NationalStandards. Silver Spring, MD: Author; 2013.

Bakker EW, Verhagen AP, van Trijffel E, LucasC, Koes BW. Spinal mechanical load as a riskfactor for low back pain: a systematic review ofprospective cohort studies. Spine (Phila PA1976). 2009;34(8): E281-93.

Bartnik LM, Rice MS. Comparison of caregiverforces required for sliding a patient up in bedusing an array of slide sheets. WorkplaceHealth Saf. 2013;61(9):393-400.

Drakulovic MB, Torres A, Bauer TT, et al.Supine body position as a risk factor for noso-comial pneumonia in mechanically ventilatedpatients: a randomised trial. Lancet.1999;354(9193):1851-8.

Eriksen W, Bruusgaard D, Knardahl S. Work

factors as predictors of intense or disabling lowback pain; a prospective study of nurses’ aides.Occup Environ Med. 2004;61(5):398-404.

Kotowski SE, Davis KG, Wiggermann N,Williamson R. Quantification of patient migra-tion in bed: catalyst to improve hospital bed de-sign to reduce shear and friction forces and nurs-es’ injuries. Hum Factors. 2013;55(1):36-47.

Lin F, Parthasarathy S, Taylor SJ, et al. Effect ofdifferent sitting postures on lung capacity, expi-ratory flow, and lumbar lordosis. Arch PhysMed Rehabil. 2006;87(4):504-9.

Marras WS, Davis KG, Kirking BC, Bertsche PK.A comprehensive analysis of low-back disorderrisk and spinal loading during the transferringand repositioning of patients using differenttechniques. Ergonomics. 1999;42(7):904-26.

Mehta RK, Horton LM, Agnew MJ, NussbaumMA. Ergonomic evaluation of hospital bed de-sign features during patient handling tasks. Int JInd Ergon. 2011;41(6):647-52.

Metheny NA, Davis-Jackson J, Stewart BJ. Effec-tiveness of an aspiration risk-reduction protocol.Nurs Res. 2010;59(1):18-25.

Michel DP, Helander MG. Effects of two types ofchairs on stature change and comfort for indi-viduals with healthy and herniated discs. Er-gonomics. 1994;37(7):1231-44.

Poole-Wilson T, Davis K, Daraiseh N, KotowskiS. Documenting the amount of manual handlingperformed by nurses in a hospital setting. Pro-ceedings of 2014 Symposium on Human Fac-tors and Ergonomics in Health Care: Leadingthe Way. Chicago, IL: The Human Factors andErgonomics Society; 2014.

Skotte J, Fallentin N. Low back injury risk duringrepositioning of patients in bed: the influence ofhandling technique, patient weight and disabili-ty. Ergonomics. 2008;51(7):1042-52.

Vasiliadou A, Karvountzis GG, Soumilas A,Roumeliotis D, Theodosopoulou E. Occupationallow-back pain in nursing staff in a Greek hospi-tal. J Adv Nurs. 1995;21(1):125-30.

Waters TR. When is it safe to manually lift a pa-tient? Am J Nurs. 2007;107(8):53-9.

Wiggermann NE, Vangilder C, Davis K. Patientmigration toward the foot of the bed affects tor-so angle. 2014 National Teaching Institute Re-search Abstracts. http://ajcc.aacnjournals.org/content/23/3/e19.full?sid=039ddc07-4db1-4bc4-aaca-5855cc684831#sec-175. AccessedJuly 15, 2014.

Williams MM, Hawley JA, McKenzie RA, vanWijmen PM. A comparison of the effects of twositting postures on back and referred pain.Spine (Phila Pa 1976). 1991;16(10):1185-91.

Neal Wiggermann is a senior biomedical engi-neer and ergonomics specialist for Hill-Rom inBatesville, Indiana.

www.AmericanNurseToday.com September 2014 Current Topics in Safe Patient Handling and Mobility 19

Be aware that any method

that involves manuallifting can cause injury

to the nurse.