Reducing thumb extensor risk in laboratory rat gavage.

Area of Science:

• Laboratory animal science
• Occupational health
• Biomedical engineering

Background:

• Gavage is a standard method for oral administration in laboratory animals.
• Repetitive thumb movements during syringe filling pose a risk for DeQuervain's tenosynovitis.

Purpose of the Study:

• To determine the forces required for drawing fluids of varying viscosities into syringes.
• To develop a guide for minimizing thumb forces during gavage procedures.

Main Methods:

• Bench tests were conducted varying fluid viscosity, syringe size (3, 5, and 10 mL), and needle length (52, 78, and 100 mm).
• Forces required for fluid aspiration were measured, with maximums up to 28 N observed for high viscosity fluids (0.29 Pa·s).

Main Results:

• A guide was developed to minimize thumb forces based on specific combinations of syringe size, fluid viscosity, and needle length.
• Lower thumb forces were generally observed with smaller syringes and larger needle sizes.
• These combinations allowed for a greater number of acceptable rat gavages per day.

Conclusions:

• Optimizing gavage technique by selecting appropriate syringe and needle dimensions for specific fluid viscosities can significantly reduce thumb exertion.
• This approach can mitigate the risk of musculoskeletal disorders like DeQuervain's tenosynovitis in researchers performing gavage.
• The findings provide practical recommendations for improving the ergonomics of animal dosing procedures.