applying ergonomics for injury free pipetting

Numerous liquid handling proce-dures rely on the ubiquitouspipette, and pipetting has long

been an indispensable laboratory skill. Theawkwardness, repetitiveness, stress andtedium inherent in traditional pipetting,however, are all harbingers of cumulativetrauma disorders (CTDs) - a major sourceof pain, discomfort, downtime and lost productivity among numerous pipette users.

CTDs - also referred to as repetitivestress injuries (RSIs) and musculoskeletaldisorders (MSDs) - are prevalent in theworkplace, and have been designated theleading single class of injury in the 1990s byOSHA. Lost-time and compensation costs aloneaverage some $20 billionannually, while total costs,which include lost productivity and indirectexpenditures, amount toabout $120 billion annual-ly. A single injury can costmore than $25,000 inmedical and indemnity claims.

Laboratory workers are hardly spared.The repetitiveness, non-optimal posturesand high forces that are common in traditional pipetting cause user injuries,several far beyond the hand and thumb -contrary to popular intuition. Researchorganizations and government agencieshave documented many risk factors(1, 2, 3)

while noting significant increases in handand elbow injuries among pipette users.(1)

Almost a decade ago, the National Instituteof Occupational Safety and Health (NIOSH)declared that a biomechanical hazard wasassociated with pipetting; in a 1996 reportcovering laboratory operations, it outlinedsteps for minimizing CTD risks.(4)

One study on associations betweenpipetting and CTDs showed that in a sample of technicians, 44%, 58% and 44%reported hand, shoulder and neck prob-lems respectively.(5) Technicians who didmore than 12,000 pipetting repetitions in aday felt acute soreness in their hands. A

sub-analysis of women pipette users foundthat pipetting for more than 300 hours ayear elevates the risk of hand and shoulderailments. With laboratory workers averag-ing about 500 hours of pipetting a year(some 2 hours a day) the severity of theproblem is clear.

What Ails PipettingWhile the long hours of repetitive motionlink pipetting and CTDs, the ergonomic deficiencies of many existing pipettes contribute significantly to the problem.Traditional axial-style pipettes, a 40-yearvintage, are built around a single axis ofoperation. These pipettes are accurate,durable and quite common, and users generally find them adequate. But theirdesign did not to keep pace with the stridesin ergonomics. As a result, they fail to shieldusers from cumulative injuries linked tolong sessions of awkward repetitive motion.

To overcome this, VistaLab Technologies,radically updated the concept of pipetting

with the introduction of the OvationBioNatural Pipette. Early on, the company’smarket research and customer feedbackshowed that customers were concernedabout ergonomics. Users were also reportingdifficulties with installing pipette tips reliably,getting them to stay on, and with removingthem. Less worrisome were the actualaspirating and dispensing of fluids.

VistaLab assembled a team to examinehow comfortably and for how long someonecould operate one of the devices. The goalwas to discover how to raise the comfortlevel and reduce stress for pipette userscurrently and mitigate injury in the longterm - then turn that into an ergonomicpipette design.

In Search of RespiteVistaLab Technologies’ project team startedout by observing and interviewing numerouspipette users. One team member, KevinCostello, President, US Ergonomics, and a20-year veteran in the field, says, “Ourpreparatory discussions focused on thethumb and the force needed to acquire andremove tips as the problem areas. Then wewent out and saw pipette users holdingthese long tubes in their hands with theirelbows high up in the air.

“We were appalled at the positioning ofthe shoulder and neck and the static loading- muscles under load with a minimalamount of motion - which created highpotential for fatigue in those muscles.”

Based on those observations, the teamdesigned a pipette to enable technicians towork in a neutral position - a naturalergonomic posture in which the relaxedarms, with the palms facing each other atabout a 45-degree angle, are held in frontof the chest area. This allows pipette usersto work in a semicircular area right in frontof their bodies. (Figure 1)

“The idea was to have the pipette usershold their arms closer to their sides. Welooked at the angle between the elbow,shoulder and hip. It was important to keepthe upper arm close to the body, minimizing

Applying Ergonomics ForInjury Free PipettingOvation BioNatural pipettes overcome ailments

associated with older axial devices

AN ADVERTISING SUPPLEMENT TO BIOSCIENCE TECHNOLOGY

Figure 1.

gloves. Wrist posture and forearm rotationwere measured with a twin axis goniometer.Shoulder elevation was measured withvideo task analysis software. All the measurements were done during the majorfour pipetting steps: tip acquisition; aspiration; over blow and tip ejection.

Finger forces required by Ovation weresome five times lower that those requiredfor the axial pipettes. (Figure 3) This translates to greater comfort, less fatigueand lower CTD risk. In a sub-analysis ofthe hand forces data, significantly lowerthumb force requirements were associatedwith Ovation versus the traditional pipettes.

The analysis also showed that wristdeviation was significantly lower with theOvation while picking up the pipette,acquiring tips and during aspiration versusthe other pipettes. (Figure 4) The values forwrist extension and flexion were lower forOvation versus the comparators in all cases.In an analysis of the percentage of timethat the shoulder is awkwardly elevated atmore than 45 degrees, Ovation proved tobe lowest in all cases. (Figure 5)

United States Ergonomics conducted com-parative tests with the Ovation and otherpipettes and analyzed the data for perform-ance levels.

US Ergonomics President, Kevin Costellonotes, “The Ovation device had statisticallysignificantly lower effort levels associatedwith tipping and de-tipping and significantlyimproved posture compared with the tradi-tional pipettes.

“For these tests, we connected electrodesto the key muscles involved in the effort -forearms, upper arms, shoulder muscles,

and the neck - we also had sensors thatmeasured dynamic posture of the body asthe device was used.

“Subjects did not know what device wasbeing tested. We tested the Ovation pipettenext to several traditional style pipettes toquantify the amount of effort needed to usethem. In simple terms, the lower the effort,the lower the stress, the lower the risk ofinjury and inversely, the higher the productivity. Productivity is the amount ofeffort required to do a task.

“You won't affect repetition, that will

always be there, but you can knock down theforce and improve posture. You can expectpeople using a device that has reduced magnitude of exposure in those areas towork longer with a lower degree of risk forany aches, pains, discomfort or injury.

“This means that there is a good chancethat someone who found pipetting painful,depending on their specific injuries, will beable to use the Ovation because this devicerequires different muscle groups - and theywill be using a lower percentage of overalleffort to get the job done.

Comparative Analysis - United States Ergonomics

abduction, which is the lifting of the elbowaway from the body. That in turn minimizesthe torque on the shoulder, the static muscleloading, and the neck and shoulder stressassociated with the pipette,” says Costello.

Other key design challenges revolvedaround the incorporation of features thatminimized the hand forces required for tipapplication and removal, within a light,well-balanced pipette.

Birth of the Ovation BioNaturalThe team soon realized that a radicaloverhaul of the basic pipette design wasneeded.

This led to a device that had an angleddesign for getting tips into and out of targetpoints. The design also stored the energyused to apply the tips in a spring for lateruse to remove the tip - a spring-loaded tipejection system.

“Storing the energy from tip applicationfor use in tip ejection eliminates the secondhardest part for the hand and is really beneficial. The angle of the device and thefact that the arm can be held at the side areother major ergonomic advantages,” saysCostello.

A small clicking sound lets the user knowwhen the tip has been securely applied orremoved. “The fact that the device providessome feedback when the tips are applied isvaluable. This eliminates pounding and theuse of additional force,” says Costello.

The Ovation uses the power grip, whichincreases the available hand strength byabout four times compared with the pinchgrip used with traditional pipettes. The powergrip is loose and relaxed, making for greaterendurance and enhanced productivity. Itscontoured shape allows for the greateststability and low pressure from contactwith the hand. A rounded plunger and tipejection button, both with reduced forces,

help to keep contact stresses attheir lowest.

Introduced commercially in 2002with an adjustable volume model, theergonomic features of the OvationBioNatural have received considerableattention. The product line has been expandedrecently to include electronic multichanneland single channel models, all of whichmaintain the ergonomic design and otheruser preferred features. Of specific note is theunique tip head on the Ovation Multichannel,which significantly lowers the force neededto acquire multiple tips simultaneously andallows the use of both hands, thus reducingstress to any specific muscle group.(Figure 2)

The Ovation has been independentlyevaluated quite favorably and is now beingused by thousands of researchers and scientists on a daily basis.

Independent Assessments of Ovation Extensive testing by ErgonomicsTechnologies Corporation has shown theOvation to be the only commercial pipettewith levels of arm flexion and extension,wrist flexion and maximum muscle activitybelow the recommended limits.(6) It is theonly pipette that allows the forearm tooperate in the pronated position, whichgenerates a markedly lower level of carpaltunnel pressure.(7)

NIOSH StudyA 2004 NIOSH study, which was a part ofthe National Occupational Research Agenda(NORA), compared the Ovation and twoaxial pipettes. A battery of ergonomicmeasurements were collected andassessed.(8)

Finger forces were measured via 19 sensors strategically placed in special

[Applying Ergonomics For Injury Free Pipetting]

Figure 2.

Duke University StudyThe Duke University Department of Ergo-nomics evaluated 61 workers’ pipettingexperiences via an extensive questionnairethat covered work habits, location, severityand frequency of discomfort.(9)

Substantial discomfort was reported(Figure 6), with areas of highest frequencybeing: neck (56%), lower back, right shoul-der (33%), right wrist (26%) and righthand (25%). The thumb, most intuitivelyassociated with pipetting, was the sixth indiscomfort frequency.

One half of the study participants wereprovided with Ovation pipettes, which theyused in their normal lab work, as part of asix-week trial. They had no prior knowledgeof the Ovation, and at the end of the sixweeks they were asked to compare thepipette they used previously to the Ovation.

There was overwhelming preference forOvation because it offered greater comfort.There was strong preference for the Ovationon questions of accuracy and general usethroughout the workday.

Chris Marchand, ResearchAssociate, Contractor, NationalInstitutes of Health

• Acquired Ovation pipettes for technical features

“I have used the Ovation pipette almost oneyear now for a high throughput-screeningproject with 96 well plates to test thousandsof compounds. We have been working withthe single channel Ovation since they werelaunched and liked them a lot.

“So we decided to try the multichannelones. Now we have two 8-channel and two12-channel Ovation pipettes, which we canuse by columns or by rows with the 96well plates. We appreciate the tips becauseof their quality and precision.

“We were aware of the ergonomic

improvements in the Ovation pipettes - andwe believe they are much easier to use inthe long run - this aspect attracted us tothem but it was hardly the overriding

reason for us. “We wanted something that was reliable,

precise and easy to use, particularly theease with which one can eject the tips.

A common misconception about ergonomicsis that once there is no heavy lifting, thereare no ergonomic issues.

Ergonomics is concerned with several riskfactor categories: posture, force, repetitionlevels, vibration (whole body or head and armvibration, really not an issue with pipetting),environmental factors (temperature, lighting,noise, etc.), physical contact stress (contactbetween the body and an object - in the caseof pipetting, how the device fits in the handand whether there are edges digging into theskin) and personal risk factors (related to

individual awareness to control exposure;overall health; and in cases where predispo-sition issues arise based on the use ofmedications that can increase risk).

If the force level is above threshold, thelikelihood of it producing an ergonomicallyrelated injury can increase significantly. But ifcategories are combined, such as force andrepetition, the likelihood of a CTD canincrease exponentially.

So even if repetition cannot be eliminated- in fact, aside from automation, repetitionreally cannot be eliminated from pipetting -

force, contact stress, postures, and user education can be greatly improved. This willhave a major positive effect at reducing exposure and the risk.

“Ergonomic issues are cumulative. Theseinjuries build over time. You have to minimizeknown risks. Pipette users who do not havepain now, who are slamming on tips andhave their arms elevated might be fine now,but if they continue for any length of time, orif the work demands increase, they could seea negative effect because of the risk factors,”says U.S. Ergonomics’ Kevin Costello.

ERGO 101


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Gabe Guzman, Post-doctoralFellow, CIIT, North Carolina

• Driven by curiosity for ergonomics“I have used the Ovation for a little bit overa year and can’t see myself going back tousing traditional pipettes anymore.Traditional pipetting feels really awkwardnow because of the vertical position.

“The Ovation was the first time I sawanything ergonomically designed for pipetting.Normally, you hear about ergonomics havingto do with the right posture when you are inyour station or sitting at your workbench. Itis not often that you see it linked to dexterity,that is, to use with your hands and for repetitive action such as pipetting.

“While I have never had any trouble withmy fingers, elbow etc., I could feel tirednessin my neck and shoulders whenever I had topipette a lot in the vertical position. Becauseof the design of the hood, your wrist wouldbe higher than your shoulder. With theOvation that is not a problem anymore, mywrist is always lower than my shoulder - my

shoulders are not as tired now. “The versatility of this pipette is its best

point - softer to use, more secure, the tipsdon’t actually fall off the sleeve of thepipette, there’s no risk of actually breakingthe tip, which sometimes happens becauseof the pushing action required with the tra-ditional pipette when picking up a tip, espe-cially if you push too hard.

Francis Weis-Garcia, Manager ofthe Monoclonal Antibody CoreFacility, Memorial Sloan Kettering

• Pipette user with carpal tunnel syndrome

“I have only used Ovation for a month or sobut I am going to buy them. Basically I can’tpipette regularly for more than five minutesbefore I start getting severe symptoms ofcarpal tunnel syndrome - pain, numbness etc.

“With the Ovation, I could go easily forabout 10 to 20 minutes. It is not a completerelief but it increases the duration I couldwork without experiencing the stress. When I

work with the Ovation, I could last as muchas four times longer than regular pipettes.

“I work through the pain and the numbness - but the Ovation definitelydecreases the amount of pain I experience.

“There are a number of great features onthe Ovation. It is lighter, but what I likemost is the different positioning of thehand, which is what I went out looking for.

“I hold it differently but instead of usingmy thumb, I am using my fingers. I waslooking for a pipette that will allow me todo that in a different position and this isthe only one that I found. All I have beenfinding were pipettes with the thumbs -granted this one still requires the thumbbut it is a different position of the hand.

“I literally sat for ten minutes at each ofthe different vendor’s displays at a tradeshow and tried all their pipettes, andOvation was the only one that I took home.”

Author Michael Wagner writes on a widerange of topics in the life sciences.

Additional information about the OvationBioNatural Pipette can be obtained atwww.vistalab.com, or by contactingVistaLab Technologies at (888) 652-6520or (914) 244-6226.

References:1. David, G., Buckle, P. A questionnaire survey ofthe ergonomic problems associated with pipettesand their usage with specific reference to work-related upper limb disorders. Appl. Ergonomics,(1997) 28(4):257-262.2. Baker, P., Cooper, C. Upper limb disorder due tomanual pipetting. Occup Med. (1995) 48(2):133-134.3. Fredrickson, K. Laboratory work with automaticpipettes: a study of how pipetting affects the thumb.Ergonomics. (1995) 38:1067-1073. 4. McGlothlin, J. D.; Hales, T. R. “Health HazardEvaluation Report”; HETA 95-0294-2594; ScienceApplications International Corporation, Frederick,MD; NIOSH, U.S. Department of Health and HumanServices, Public Health Service, Centers for DiseaseControl and Prevention; August 1996.5. Bjorksten, M. G., Almby, B., Jansson, E. S. Appl.Ergonomics (1994) 25(2):87-93.6. ETC References7. Rempel, D., Bach, J., Gordon, L., Yuen, S. Effectsof forearm pronation/supination on carpal tunnelpressure. J. of Hand Surgery (1998)23A:38-42.8. Presentation by Ming-Lun (Jack) Lu, PhD,Research Ergonomist, Division of Applied Research &Technology - NIOSH Special Session-ErgonomicIntervention Studies9. A comparison of traditional and alternativepipettes - comfort and preference - Presentation byTamara James, MS, CPE, Ergonomics Director,Duke University and Medical Center.

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applying ergonomics for injury free pipetting

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