Ergonomics is the study of designing equipment and tasks to optimize human well-being and system performance. The document discusses various types of ergonomic research conducted in anesthesiology including task analysis, workload studies, attention studies, and critical incident analysis. It provides examples of how ergonomic principles were applied to modernize anesthesia machine design, such as reducing errors from improper gas connections or flow settings. The goal of ergonomic guidelines is to produce easy to use, reliable devices through principles like visibility, natural mapping of controls, and constraining undesirable actions.

1. ERGONOMICS IN ANAESTHESIA
PRESENTER: Dr. SHAHBAZ ALAM
MODERATOR: Dr. RAJIV CHAWLA
Chairman Departmentof Anaesthesia
Rajiv Gandhi Cancer Institute and
Research Center, Rohini, New Delhi

2.  What is Ergonomic.
 Examples of ergonomic researches.
 Ergonomic guidelines.
 Progress in Ergonomics.
 Types of Ergonomics.
 Basic requirement of Ergonomically efficient operating
room.
 Ergonomic injuries.
 Prevention of Ergonomic injuries.

3. 1.ERGONOMIC
o Ergonomics is a discipline that investigates and
applies information about human requirements,
characteristics, abilities, and limitations to the
design, development, engineering, and testing of
equipment, tools, systems, and job.
o It is the study of work & way to make jobs / tasks
in a better way safely.

4. Ergonomics

5. Scope of ergonomics
In 1972 Edwards introduced
S.H.E.L model.
As per this model all jobs are
performed by three classes of
resources,
1.Hardware: equipment or
machine for the job
2.Software: procedures and
rules
3.Liveware: people
Live
ware
Soft
ware
Hard
ware
Enviroment

6. Why Ergonomics?
Benefit of Patients : Safety
Benefit of Anaesthesiologist : Comfort / ease
To reduce the risk of
•Accidents
•Injury
•Ill health due to poor ergonomics
Increase Performance / Output
Reduce Sickness absence / Costs
Everyone in any organization is at risk and it is not
just “heavy” or “physical” jobs that cause injury

7. Ergonomic is the discipline of designing and testing of this
S.H.E.L model in view of improving safety, comfort and work
efficiency.

8. Hypoxia : A constant Threat !
Decades ago, accidental delivery of hypoxic gas mixtures was a
constant threat during general anesthesia.
In some cases the anesthesiologist mistakenly turned the wrong
gas flow control knob or failed to recognize that the oxygen
cylinder was empty.
 In another case, a technician placed the flow meter tubes in
the wrong positions while servicing the anesthesia machine.
These small human errors led to major injury or death of the
patient.

9. Modern Anesthesia Machines :
Reduced Human Errors
With modern anesthesia machines, the risk of
accidental hypoxia has been dramatically reduced. In
effect, the potential for human error has been reduced by
redesigning the equipment.
The concept that, equipment can be designed for
optimal performance by the human user is one of the
core principles of ergonomics.

10. • Ergonomics is both a science and a profession, including
both research and application.
• One goal of ergonomics research is to understand and
describe the capabilities and limitations of human
performance.
• Another is to develop principles of interaction between
people and machines

11. 2.Ergonomics Research
A. Task Analysis
B. Workload Studies
C. Attention Studies
D. Automation & New Technology
E. Critical Incident Studies

12. Examples of ergonomics research are:
The investigation of visual perception in relation to a
particular task, and auditory vigilance in relation to attention.
Application involves the use of these data in the development
of equipment.
For example, the selection of color coding for displays is
based on understanding of visual perception, whereas
auditory vigilance data are used for development of alarm in
machines.

13. The number of ergonomics studies in anesthesiology continues
to grow. The focus of these studies has been to identify human/
machine interface factors that affect patient safety and the
anesthesia caregiver’s job performance.
Many recent efforts are concisely summarized.

14. A.TASK ANALYSIS STUDIES
Drui and colleagues’s, time and motion study for
anaesthesiologists:-
• Found that filling out the records occupies a large
proportion of time for anaesthetists.
• Anesthesiologist’s attention was directed away from the
patient or surgical field 42% of the time.
• Drui’s recommendations were published and based on the
study, electronic anesthesia record-keeping systems and
integrated anesthesia workstations have attained
commercial viability.

15. B.WORKLOAD STUDIES:
• Workload is multidimensional and complex
• When workload increases, the sympathetic nervous
system is activated, leading to a variety of physiological
changes. For example, increased workload is associated
with increases in heart rate or respiratory rate.
• Work load is highest during induction and emergence
phase of anaesthesia.
• Toung et al reported that anaesthetists heart rate increase
39% to 65% of base line during intubation, though more
experienced anaesthetist, manifested less.

16. C. ATTENTION STUDIES:
• Cooper and Cullen described a method for investigating
auditory vigilance.
• They used a computer-controlled device to occlude the
stethoscope tubing silently at random intervals during
routine general anesthesia.
• Study participants were instructed to press a button to
restore function, whenever they perceived the absence of
sounds.
• The elapsed time between the occlusion of the tubing and
the press of the button was automatically recorded.

17. • In another study, Loeb evaluated visual vigilance in eight
anesthesia residents by displaying numbers at random
intervals on an OR monitor during operative procedures.
• The residents were instructed to detect an “abnormal”
value and asked to respond by pressing a button on the
anesthesia machine.
• The response time was recorded.
• Then compared with Cooper’s study:-
It appears that response times in the OR are longer
for visual than for auditory signals.
C. ATTENTION STUDIES: II

18. In another attention study it was found that overall,
anaesthesiologists looked at the patient monitor :
 8% of the time prior to injecting induction agents.
 20% of the time after injecting induction agents, during
routine induction.
 30% of the time after injecting induction agents, during
eventful induction.
C. ATTENTION STUDIES: III

19. D. Automation And New Technologies
• A recurrent application of task analysis, workload, and
attention studies lead to investigate the effect of
automation and new technologies on anesthesiologist
performance.
• Different studies done for checking, whether it decreases
workload and increases efficiency or it removes human
from the information loop.
• Then after automated record keepers, automated drug
dispensing carts are now available.

20. E. Critical incident studies
• Critical incidents- defined as occurrence of human error
or equipment failure that if not discovered or corrected in
time may lead to increased length of hospital stay or even
death.
• Examples;-syringe and drug ampule swaps, drug
overdoses, wrong i.v line used, endotracheal tube
disconnection.
• Cooper and colleagues studied in 1975 and first applied
these critical incidents to anaesthesiology, they found that
human errors were responsible for 65% to 70% of
incidents.
• On the basis of their findings they recommended a
standardized system of syringe labels and redesign of the
breathing circuit to prevent disconnections.

21. E.Critical incident studies II
• In 1993 Runciman et al: done an exhaustive analysis of the
first 2000 incidents reported in Australian Patient Safety
Foundation report and found that:-
 83% incidents related to Human Error.
 9% related to Equipment Failure.

22. 3.Ergonomics Guidelines
PRINCIPLES OF GOOD DEVICE DESIGN:
The goal is to produce devices that are
Easily maintained.
Have an effective user interface.
Are tailored to the user’s abilities.
This is best accomplished during the early phases of system
and equipment design, when the ergonomics and
engineering specialists can work together with end users to
produce a safe, reliable, and usable product.

23. Progress In Anesthesia Machine Design

24. 4. PROGRESS IN ERGONOMICS

25. What did Ergonomics do ?
Make things visible.
Provide good mapping.
Appropriate constraints creation.
Design for error.
Visual display.
Auditory display.
Manual control.

26. Make Things Visible
• People expect certain objects to always function in a
particular manner, like knobs are for turning, buttons are
for pushing, and so on
knob
button

27. Making Things Visible
HANDLE

28. Provide Good Mapping
Mapping is the relationship between an action and a
response
 Natural Mapping
 Artificial Mapping

29. Mapping
Natural Mapping : like squeezing the bag to inflate the lung.
It is innate.
Artificial mapping: have to learn, like turning the oxygen flow
control knob counter clockwise to increase gas flow.

30. Appropriate Constraints Creation
• It is done to facilitate simple, logical and innate operation.
• When a series of indicator lights are arranged in a row,
each with a switch underneath, indicates particular switch.
Here another constraint lies,
the selection will get finalized
after pressing the knob.
knob
constraints

31. Design For Error
• It is also a type of constraint that prevents an
undesirable action.
EXAMPLE :
 Vaporizer interlock
 Pin index in cylinders:

32. Color Coding of cylinders:
oxygen Nitrous Oxide CO2
Design For Error : II

33.  Display magnitudes: Numeric or Graphic
 Grouping of displays: similar items are grouped together,
so that easy to read-
 Object display: Pictorial
Visual Display
c
c

34. • Display coding: Colour and numeric codes were
superior in any task but colour is most effective
coding method.
• Thus we can quickly and easily find them-
Visual Display

35. Visual Display : Monitor

36. Visual Display : Anaesthesia Machine

37. Auditory Displays
• Auditory Displays: Primary advantage of human auditory
system is that it can simultaneously detect signals from
multiple locations.
• This made auditory displays useful for displaying alarms
and warnings, those require immediate response.
• Example- pulse oximeter, low and high gas pressure
alarms.

38. Manual Controls
• Just as the equipment transmits information to the user
through displays.
• The user transmits information to the device via controls.
• Different types of controls are preferable for different kinds of
tasks.
• Examples Switches or buttons are used to transmit binary:-
on and off information. Continuous information is usually
conveyed with knobs, wheels, levers, or pedals.

39. 5.TYPES OF ERGONOMICS
• Physical ergonomics is the human body’s responses to
physical and physiological work loads.
Repetitive strain injuries, vibration, force, and posture
fall into this category.
• Cognitive ergonomics deals with the mental processes and
capacities of humans when at work.
Mental strain from workload, decision making, human
error, and training fall into this category.
• Organizational ergonomics deals with the organizational
structures, policies and processes in the work environment.
Examples: shiftwork, job satisfaction, motivation,
supervision, teamwork, telecommuting, and ethics.

40. 6.Basic requirement of ergonomically
efficient operating room
1.Induction room and post operative care unit may be
integrated with operating room to minimize
anaesthesiologist movement and fatigue.
2.The size of the operating room can be as per the
requirement but recommended size is 6.5 m x 6.5m x
3.5 m for easy movement of the staff.

41. Basic requirement of ergonomically
efficient operating room….
3.The surface/flooring must be slip resistant, strong &
impervious with minimum joints (e.g., mosaic with copper
plates for antistatic effect ) or jointless conductive tiles. The
recommended minimum conductivity is 1 mΩ and maximum
10 mΩs.
4.Walls and ceiling should be aesthetically pleasing
nonporous, fire resistant, water and stain proof, seamless,
non-reflective and easy to clean. A semi matt surface paint
reduces reflection of light and tiring of eyes of OT personnel.

42. Basic requirement of ergonomically
efficient operating room….
5.The sliding doors are preferred to the double action leaf
type since they are more user friendly, save space and
prevent air turbulences.
6. Sufficient electric points should be available on the wall to
prevent entangling of wires and also preferably at a height of
less than 1.5 meters from the floor for easy approach.
7.Taps in the scrub room should be knee/elbow operated or
preferably electronically controlled taps activated by infrared
sensor.

43. Basic requirement of ergonomically
efficient operating room….
8.Central air conditioning should ensure temperature
range of 18-24° C with 50-60% humidity levels. A
minimum of 20 air exchanges/h should be ensured. It is
preferred to have 100% fresh air.
9.Sound level in OT should be limited to 25-35 db.
10.There should be emergency communication system
that can be activated without the use of hands.

44. Thus, ergonomics
• All about patient’s increase safety ,anaesthetist’s
comfort and increase work efficiency.

46. 1917 BOYLE machine

47. Snow face piece 1857
Heavy, cumbersome, non transparent
to
Light weight, easy to hold ,transparent

48. Torn pocket with
Suspended instruments
PRIVATE ITEMS OVER
LOADED POCKET pager
V-neck with private items
TYPICAL CLOTHINGS OF SURGICAL STAFFS
Some interesting ergonomics

49. Some commonly used items
which are related to safety and comfort
Courtesy : Ergonomics

50. GOOD POSITION :
BACK FRIENDLY
BAD POSITION :
CAN CAUSE MUSCULOSKELATOL DISEASE

51. Scope of ergonomics
Live
ware
Soft
ware
Hard
ware
Enviroment
Use your brains while
adopting a new technology !
Its all about safety & ease of
working and not just adding
complexities.
It requires training and
adaptation to the new device.

52. 6.Ergonomic injuries
Tendon disorders:
Inflammation of tendon or tendon sheathing caused by
repeated rubbing against ligaments, bone, etc.
Ex. Lateral epicondylitis (tennis elbow).
Nerve disorders:
Compression of nerves from repeated or sustained
exposure to sharp edges,bones,ligaments,or tendons
Ex. Carpal tunnel syndrome.
Neurovascular disorders:
Compression of blood vessels or nerves from repeated
exposure to vibration or cold temperatures
Ex. Raynaud’s phenomenon (white finger syndrome)

53. Ergonomic injuries
Strains & Sprains:
Injury to connective tissue caused by single forceful
event: lifting heavy objects in awkward position.
Common to large body segments (i.e. back, legs,
and shoulders).
Risk of injury increases with the presence of
multiple risk factors.

54. Ergonomic injuries

55. Musculoskeletal Disorders- MSDs
o Musculoskeletal Disorders affect the muscles, nerves
and tendons. They are:-
o Carpal Tunnel Syndrome
o Tendinitis
o Rotator cuff injuries (shoulder problem)
o Epicondylitis (elbow problem)
o Muscle strains and low back pain

56. Work Related Upper Limb Disorders

58. 7.PREVENTION
• Warm up & stretch before activities that are
repetitive, static or prolonged.
• Take frequent breaks from any sustained posture
every 20-30 minutes.
• Stop painful activity.
• Recognize early signs of inflammatory process, and
treat early.
• Be aware of workstation environment.

59. a) Maintain erect position of back and neck
shoulders relaxed.
b) Position equipment & work directly in front of
and close to your major tasks.
c) Keep upper arms close to the body, elbows
90-100 degrees
d) Keep feet flat on floor, upper body weight resting on
“sits bones”
e) Wrists as neutral as possible; safe zone for wrist
movement is 15 degrees in all directions
Maintain neutral posture during office work:-

61. o
o
o
o
o
One of the biggest injury risk factors is static posture.
Try to spend at least 5 minutes /hr hour away from your computer.
Remember to only stretch to the point of mild tension.
Try to incorporate the stretches into your daily routine.
This slide provides some illustrations of simple active stretches to
perform at the office.
Hand Exercises
o Tightly clench your hand into a fist and release, fanning out the
fingers. Repeat 3 times
Good ergonomics

62. THANK YOU