Cardiac Output, Venous Return, and Their Regulation
Ergonomics demerdash
1.
2. By
Tarek Youssef Ahmed Youssef
(MD, MRCS, MRCPS, MIS Master)
Assistant professor of General Surgery
Ain Shams University
3. “Ergonomics” is a Greek word: "erg“ or “ergon”
meaning work & "nomas“ or “nomoi” meaning
natural laws.
The way in which the careful design of
equipment helps people to work better &
more quickly.
It means the “application of biological and
engineering data to problems relating to the
mutual adjustment of man and the machine”.
4. PHYSICAL : Sensory & Motor
Mental : Mental Perception.
ORGANIZATIONAL: Optimization
of work & environmen.
6. Laparoscopy needs considerable technical skill.
Surgeons are challenged with increased
physical & psychological workloads from
operating with inadequate and insufficient
laparoscopic machines & instruments,
Studies had shown that 8 – 12 % of lap
Surgeons have cervical & U L problems
While 9 -18 % have stiffness.
7. TO IMPROVE EFFICACY.
TO REDUCE ERRORS.
TO MINIMIZE PHYSICAL, MENTAL
& PSYCHOLOGICAL WORKLOAD
ON SURGEONS.
9. VISUAL SYSTEM:
CAMERA, LIGHT SOURCE, CABLE ,
SCOPE & MONITOR
VISUAL HINDERANCE : BLOOD,
FLUIDS , SMOKE & FOGS
ADEQUATE EXPOSURE:
POSITION OF SCOPE, CAMERA
MAN,RETRACTORS, DISTANCE FROM
TARGET & MONITOR
10. It is the angle between scope & target.
Better illumination & image quality at the
centre.( target & instrument )
Least image distortion & better
performance when optical angle is 90 ْ (
less errors ).
Angled scopes give only better access
Rotation of angled scope wider field
but with distortion of field periphery
11.
12. HEIGHT : Level with eye – 15 to 30ْ
LOCATION :
1. Near enough to op. field
2. Visual & motor axis alignment
TYPE : Flat screens are best
RELATION BET. SURGEON’S EYES,
HANDS, TARGET & MONITOR
13.
14. Magnification.
Smaller field.
Blind areas.
Augmented instrument movements.
Loss of instrument localization.
Rapid zooming or side camera movement
lead to visual & psychological stress on
surgeon (jerky).
15. SELECTION OF VISUAL SYSTEM
CLEARANCE OF CAUSES OF HINDERANCE
PROPER SELECTION OF SCOPE SITE &
ANGLE
ADJUST VISUAL ANGLE
PROPER ZOOMING
PROPER EXPOSURE OF TARGET (TABLE
POSITION & RETRACTORS)
ADJUST MONITOR DISTANCE COLORS,
BRIGHTNESS & HEIGHT
ROLE OF CAMERA MAN
16.
17.
18. UPRIGHT
MINIMAL BENDING
NO TWIST , NO TILT
SHOULDERS : Resting
ARMS : 20ْ abduction 40ْ int. rotation,
RESTING
ELBOW : 90ْ – 120ْ Flexion
WRIST :Free, neutral, avoid excessive
ulnar deviation or flexion
HANDS & FINGERS : Should fit instrument
handle, sensitive parts should operate
functional parts of instruments freely
19. Absent tactile feeling & feedback
Long rigid instruments
Fixed port sites
Mirror effect
Lever action
Increased force requirement & constrains of
moving instruments through trocars
Decreased manipulation dexterity (limited
range of movements)
20. DARK ROOM SITUATION ( nurse handing
wrong instuments & surgeon passing them
with difficulty into ports ).
SPAGHETTI ARRANGEMENT OF TUBES , CORDS
& CABLES ON TABLE.
21. Impaired depth perception
Unnatural location of operative field
on monitor (indirect vision) EYE
STRAIN
Disorientation of instrument
movement esp. in presence of more
than one instrument in the field.
CROSS SWORDING, ROLLING OVER
22. Biomechanical problems may occur with
inadequate laparoscopic instruments:
◦ Excessive flexion and ulnar deviation of wrist.
◦ Musclo-skeletal strain on neck, shoulder & back.
◦ More stastic postures than in open surgery due to
increased concentration, indirect vision.
◦ Less efficient handle-to-tip force transmission i.e.
(1/3) unlike haemostat (3/1).
25. Each azimut angle should be equal (ideal )
Types:
◦ ON AXIS OPERATING : Means scope bet. Working
instruments in same direction (ideal )
◦ OFF AXIS OPERATING : Both working instruments
are on one side of scope
( dominant or non dominant side ).
◦ OFF AXIS OPERATING – REVERSE ALIGNMENT : scope
against instrument direction ( the most difficult )
26.
27. Angle bet. Rt. & Lt. instruments
Ideally should be 60 ْ
Trocars should be placed 10 cm apart
Best trocar arrangement is TRINGLE,
DIAMOND or FAN with scope in between
working ports
28.
29. Angle bet. Instrument shaft & Target plane
Ideally should be 45 – 60 ْ
Should allow comfortable movements of
instruments with no Lever action
INTRACORPOREAL / EXTRACORPOREAL part
of instrument should be > 1
Better performance.
30.
31. ◦ A handle able to accommodate various hand
sizes.
◦ The handle must be as small as possible &
designed for one-handed use.
◦ The sensitive areas of the hand should operate
functional elements.
Pistol handles need less power than finger in ring
handles.
The use of finger tip instead of finger base is more
comfortable in ring handles.
Excessive shoulder movements are to be avoided.
32.
33.
34. It is crucial to choose
most advantageous
trocar arrangement
The arrangement
should align the
surgeon, laparoscope
and monitor to the
surgical field.
35. Crossing swords & Striking handles → trocars
placed too close
Rollover → between laparoscope and instrument
The surgeon & assistant need to experience them
once to adjust for them
36. Patient Positioning & Trocar Configuration
depend on:
◦ Pathology being approached
◦ Patient body built
◦ Prior surgical history
◦ Surgeon’s experience
Trocars should not cross one another
(crossing swords)
37. Optical angle should be as close to 90ْ as
possible
Sutures are better performed in vertical rather
than horizontal plane
Working on axis is best
Int./Ext. parts of instrument should be >1
Movements should be steady,
slow & purposeful
PRACTICE MAKES PERFECTION
38. TRAINING SHOULD INVOLVE SURGEONS,
CAMERA MEN, NURSES & TECHNICIANS
COMPUTERIZED SIMULATORS ARE OF VALUE
TO TRAIN SURGEONS & STUDY INSTRUMENTS
ERGONOMICS
