Biosafety Hood Work
The following elements are required for completion of each cycle: reach to the left side for specimen vials; vortex specimens prior to or while pelletting; uncap specimens; apply new pipette tip; aspirate serum; dispense into beaded vial; release pipette tip into the sharps container; put down pipette; cap specimen tube and the beaded vial.
Several potentially risky body postures associated with pelletting were initially observed. These include reaching forward to dispense the pipette tip, reaching behind for the specimens, externally rotating the shoulder when reaching for the specimens, pinching with fingers to uncap and cap specimen and small plastic vials during pelleting and beading, and contact stress from leaning on the front edge of the hood. Vibration from vortexing the specimens and glare from the hood window were the other identified risk factors. Due to the repetitive nature of the pelleting task, lab specialists are potentially at risk for developing shoulder and hand injuries.
One recommendation is to install a new, larger hood that would be able to incorporate an ice bath with the serum vials and pelleted vials at the same time.? Ideally, to accommodate all of the materials currently stored in the hood and yet maintain the commonly used materials at a reasonable reach distance, the hood dimensions should have 5" x 30" dimensions, height-adjustable base stand, inclined sliding sash, curved air foil, narrow perforated front grill, and ?wells? for tall containers. Latch-mode pipettes eliminate depressing and holding the plunger and manually controlling aspiration rate (magnetic latch and trigger release) (Rainin, n.d.). To reduce repetition, a multichannel pipettor should be used for large aliquotting tasks and electronic pipettors should be used for mixing or aliquotting. High forces are required to open the plastic vials and specimen vials, which resulted in awkward wrist and finger postures. To decrease the twisting motions during capping and uncapping, plastic vials with fewer threads could be used. To prevent awkward static postures, the seat height, depth, and backrest of the chair should be easily adjustable.
Evaluation of Intervention
- Incorporation of the ice bath into the hood eliminates extension and abduction of the shoulder
- Shoulder flexion is reduced
- Lumbar support is increased
- Pinch grip force is reduced
- Reach area in the hood differs for individuals of different sizes
- Multichannel pipettes and other designs of the pipette cannot completely eliminate all forces and repetitions associated with pipetting
Semi-Quantitative Evaluation of Intervention
- Reduction of Identified Risk Factor
- No New Risk Factors Introduced
- Productivity not Reduced
- Low Cost
Other Possible Interventions
Other pipette designs may alleviate the thumb force and awkward postures of the wrist.
Submitted by Angela Menegay (UC Berkeley) and Irina Foxman (UCSF)