|Year : 2016 | Volume
| Issue : 5 | Page : 306-311
Ergonomical aspects of anaesthetic practice
RS Raghavendra Rao
Department of Anaesthesiology, BMCRI, Bengaluru, Karnataka, India
|Date of Web Publication||3-May-2016|
R S Raghavendra Rao
Department of Anaesthesiology, Victoria Hospital, Fort Road, Bengaluru, Karnataka
Source of Support: None, Conflict of Interest: None
Anaesthesiologist's service begins as a general physician, goes on as an investigator cum data analyser leading to the architectural planning of a forthcoming surgical event, but only after articulately convincing the subject along with his kith and kin. In the era of rapid developments in the field of medicine which includes relevant developments in anaesthetic care, an adequate work environment has to be provided to the anaesthesia team so that all anaesthetic procedures can be carried out safely and efficiently and an optimal workflow can be established in the operating room environment. Such ecological state demands an updated knowledge and ergonomics to aid him. Unfortunately, ergonomics is an area of anaesthesia that has received little attention and should be addressed through more education and training for workplace well-ness. Hence, an attempt is made to discuss few aspects on ergonomics for the interface between anaesthesiologist-machine-patient systems regarded as human-machine-system.
Keywords: Anaesthesia, design, ergonomics, layout, performance
|How to cite this article:|
Raghavendra Rao R S. Ergonomical aspects of anaesthetic practice. Indian J Anaesth 2016;60:306-11
| Introduction|| |
The anaesthesia workplace can be regarded as a human-machine-system complex, which not only involves the anaesthesiologist, but also the anaesthesia technicians and nurse anaesthetists involved in patient care. In this 'cockpit', the operator has to handle several devices.  The intensive collection of information and correlating and analysing them before putting them into action is really challenging. Not only visual but also auditory cues have to be integrated in the action-control-loop. It is obvious that in some stressful and complex situations, a perceptual and cognitive overloading could occur to the anaesthesiologist and, therefore, may inhibit an efficient and safe interaction. The design of the interfaces and the form of information presentation has a significant impact on these aspects. This is more pertinent in the present day since the care of anaesthesiologist extends beyond the four walls of the operation theatre, involving critical care and services extended at remote locations.
| Terminology|| |
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 jobs'. The objectives of ergonomists are to improve safety, performance, and well-being by optimising the relationship between people and their work environment. It is the science of fitting the job to the worker and the practice of designing equipment and work tasks to match the capability of the worker. The terms ergonomics, human factors, human engineering and usability engineering are often used interchangeably; however, the term ergonomics is used exclusively. ,
Ergonomics in a literal sense would mean, 'scientific study of a man at work'. The neglect of human errors in such working environment is very common but often ignored. This thought of ergonomics is mainly applied in health care industry and some branches and aspects of the medical field in the last few decades. The word 'ergonomics' is derived from two Greek words, i.e., ergo: Work and nomos: Base or foundation. It was coined by Murrel in 1949, who led a team of scientists in England during World War II.  Those were mostly designed to war and weapons situations and slowly started expanding into other fields of social upkeep. Then, it started progressing as human factor engineering.  The growth has been enormous in the field of medicine, more so in those concerned with the intensive care, radiology, anaesthesiology, monitors and laboratory, etc. Awareness of the importance of human factor in ergonomics (HFE) in medication safety and other patient safety domains have significantly increased. Patient safety leaders call for increasing involvement of HFE in helping not only to characterise system factors that contribute to patient safety but also to inform system design interventions. , Ergonomics can be applied as an effective and useful method for the practice of anaesthesia in a model consisting of three elements and two interfaces.  These can be depicted with their relations as follows:
Objectives of ergonomics are: (i) To improve safety, (ii) to improve performance, (iii) upkeep the well-being.
Anaesthesiologist - (ergonomics) - equipment - (bio-engineering) - patient: Here there are three elements viz., anaesthesiologist, equipment and patient. There are two interfaces, ergonomics and bio-engineering. The first interface, ergonomics which was much neglected in the past is now gaining huge importance in providing a proper 'machine/equipment'. The latter interface is concerned with the interaction between patient and technology.
Ergonomical factors contributing to the workload for anaesthesiologists include issues associated with hardware such as clarity and intelligibility of monitors, range and accuracy of alarms, availability and reliability of equipment, the degree of automation, and environmental issues such as lighting, noise, temperature and humidity, the layout of theatres and anaesthetics. 
There are four aspects to be concentrated under ergonomics in relation to anaesthesia:  (1) Equipment design (2) Work-place layout (3) Environmental conditions such as lighting and legibility (4) Skill acquisition, productivity and safety.
| Equipment design|| |
The equipment, its parts and design needs utmost research and implementation. The levers and handles should suit and be at the comfortable position to operate. It should be thick enough to be securely held and preferably possess feel grip. It's better if they are made agent specific, as seen in flow control knobs of anaesthesia machines. They must be positioned such that movement should not cause interference with knuckle and prevent excessive movement of the elbow. There should not be sharp edges or high spots. There should be proper blocking of static charges and proper insulation. The evolution of anaesthesia machine to the present day anaesthesia workstation, not only resulted in better safety features with visible, audible and programmable alarms but also a composite, integrated style with inbuilt monitor, ventilator and data recording features as well. They are also expected to have stand-by power backup option. Hence, the design is well-planned such that there is option of the desired parameters to be chosen and an option for upgrading easily without replacing the whole equipment. Another measure is the introduction of anaesthetic scavenging system that has reduced the operating room pollution and minimised the risk of exposure among permanent theatre personnel. Although the percentage of anaesthetic mishaps that are primarily due to equipment failure appear to be relatively small, contribution due to poor equipment design in the incidence of error or mishap may be significant. 
| Work-Space Layout|| |
The arrangement and selection of inventory and furniture should be given proper thought with improvisation. One of the simplest and most basic measures to take note of in the operation theatre is to replace the traditional fixed rotating stool at the head end of the operating table for anaesthesiologist. This to be replaced with good quality ergonomically designed height alterable seat with a provision for writing desk. A chair with castors, height adjustable with proper backrest and easy accessibility with manoeuvrability would be desirable. Today's design of operating tables, anaesthesia machines, monitors and their controls suggests the ideal build of an anaesthesiologist is something grotesque. The bulk of the soda-lime canisters on the side of a machine, drawers or other obstructions under what are meant as a work-surface and writing surface and the distance to operating table controls and lights are all instances of engineering which may be mechanically good but which ignore the dimensions of the human who is to operate them.
These examples and many more suggest it is worth reviewing all aspects of anaesthetic practice to find more effective ways to arrange equipment and other facilities optimally. The size of the operating theatre must allow sufficient room for the nurses and technical and helping staff to circulate. Preferably, there must be a separate induction room and one for recovery with provision to attend to any complications if they ensue. The field of cognitive engineering and decision making has grown rapidly in recent decades. It will cover current research, theory and practice in ways that not only provide for the sharing of information across interested parties but also serve to move the field forward. 
Congestion of wires, tubes and lines in an operating theatre leads to frequent episodes of tipping over (Spaghetti syndrome). Solutions varying from a simple colour coded elastomeric bands holding different sets of tubes and wires,  and use of a single console for multiple set of wires, to use of wireless technology to connect patient sensors with monitors have been tried and suggested.  Ofek et al. proposed an integrated self containing "built in" operating table which manages the entire process of patient flow and control of supply systems and environmental conditions. The design utilises the space below the operating table to store equipments required for patient safety, provide conduits for compressed gas, vacuum and drain systems, water for heating and cooling, communication lines and backup power supply. The main power supply units, generators, pumps and central plumbing tubes are to be stored in a lower intermittent service floor, and pass directly through the floor into the base of the operating table. All devices will be connected to electrical sockets located inside the table, linked to the central electrical power supply. 
| Environmental Conditions: Lighting and Legibility|| |
Proper lighting, visibility and legibility (readability) are the most desirable features in indoor engineering. In the past only surgical lighting was given importance. Over the decades, more emphasis is on the team and theatre as a whole. The light should be good enough to appreciate colour changes in the operating field including colour changes in the patient (cyanosis/pallor). Lighting should be ample enough to view the monitor display clearly without any glare. The problems faced with routine top lights to present day shadow free, non-glare able, non-heat producing lights (preferably of 70,000 to 1,20,000 luminous intensity) are appreciable. The ratio of intensity of general room lighting to that at the surgical site should not exceed 1:5, preferably 1:3. 
There is provision to adjust these lights directly by the operating team or independently manually or by remote. These lights have almost nullified the problem of glare.
Display of typed material on equipment: Numbers and letters should both be legible at a distance of 30 cm. The ratio of the height to distance should be 1:200. There must be a protocol for the style of print and font which makes them easiest to read and also for the wording placed on the equipment. Mistakes occur from parallax, pointers hiding numerals, scales whose direction of increase contradict the user's expectation, polycarbonate plastic covers which reflect light and scratch easily; they may better be avoided or modified to suitable alternatives. Displays should be grouped according to function, follow a logical sequence from top to bottom and left to right, and have an obvious relation in space to the controls which alter them. Non-urgent information, such as the maker's name and model and serial numbers of equipment, should not be on the front face. Controls and displays for maintenance should be shielded while controls which are critical to life should be handiest and protected against accidental activation or de-activation.
The design of displays is a large subject on its own, and entails simple, legible, and standard presentation of data. Information presented to the anaesthetist may be of measured quantities or status. Different grades of system status are best shown by indicator lights coded green, amber or red, flashing 3-5 times per second as visible alarms' along with audible warnings to be used. Even low-level noise disturbs good working rhythm and may mask necessary conversation or audible signals. Distracting chatter, noisy equipment and inappropriate impromptu lectures may all be intrusive.
Apart from lighting and vision, there are other environmental factors which can affect theatre staff adversely, as well as the patient. Temperature and humidity obviously need control, and there should be simple gauges for these in operating theatres, together with an efficient hospital engineering service to maintain them in good working conditions. Apart from impairing efficiency of work, factors in the environment can be downright dangerous, but this very danger has meant earlier recognition and control of such threats as anaesthetic gas pollution, electric shock and radiation. Some attention also has to be paid towards the workload of hospital staff regarding lack of sleep and efficiency and stress of all kinds has to be considered in planning the working environment of operating rooms. Physical problems that may be encountered include back and neck ailments. Some of the basic requirements for designing an ergonomically efficient operating room are listed in [Table 1]. 
|Table 1: Basic requirements for an ergonomically efficient operating room|
Click here to view
| Skill Acquisition, Productivity, and Safety|| |
'Threading a needle' is a good example of an illustration of skill. This is a skillful task where two hands should remain steady together by abolishing normal hand tremor until the completion of the task. Such skills are learnt very fast when regularly practiced. Someone who has found it difficult to thread a needle will find this task laborious in his entire lifetime, unless regularly practiced. Few anaesthetic procedures have been analysed regarding their elements. In many skills, it is the accuracy of feel rather than the accuracy of movement that is important. A budding anaesthesiologist may learn the resistance of vein wall through a run of haematomas. Analogies suggest learning is quicker with better feedback and if simulators are used for teaching. Understanding the forces involved, and the details of the common pattern of hand posture used by experts are very essential.
The psychological analysis of how skills are acquired can be carried further, defining stages of learning. The first of these is the coding of individual movements, especially hand and body posture. An example of this is been given earlier in Environmental conditions. The later stages are arranging coded elements of movement into a sequence, which eventually becomes an unconscious act like the sub-routine of a computer programme.
A basic implication of ergonomics for anaesthesia is to have a fresh look at the requirement of the infrastructure and the work of the anaesthetist to define his activities in a logical and detailed way. The ergonomics of controls and displays has special relevance as anaesthetic technology became more complex and advanced. It is even more important to acquire skills in certain aspects of work, so that they are carried out by specially trained technicians and nurses under the supervision of the anaesthesiologists instead of directly by them. The introduction of least exposure radiology equipment (C-arm mobile x-ray unit), use of ultrasound and echocardiogram in the areas of monitoring has made features non-invasive and more reliable adding to better patient safety. Use of ultrasound has grown beyond monitoring purposes and has largely influenced the practice of regional anaesthesia. It is found to increase the success rate and reduce the onset and procedure times for peripheral nerve blockade compared with traditional nerve localization techniques. The presumptive mechanism for these benefits is the ability to accurately inject local anaesthetic circumferentially around the target nerve.  However, there exists little information regarding the competencies involved with use of such practices. A study assessing the common inadequacies during performance of an ultrasound-guided block by novice in the field has provided important ergonomical inputs which help in training of novice. 
Components of ergonomics
To optimise system performance while maximising human well-being and operational effectiveness, ergonomics embrace a range of human centered issues relevant to equipment or systems design and training, including  (i) Body size (anthropometry), motion, and strength capabilities (biomechanics) (ii) sensory-motor capabilities vision, hearing, haptics (force and touch), dexterity (iii) cognitive processes and memory (including situational awareness) (iv) training and current knowledge relating to equipment, systems, and practices (v) training and current knowledge of medical conditions (including emergency conditions) (vi) expectations and cultural stereotypes relating to the operation of equipment (vii) general health, age, motivation, stress levels, mental fatigue and performance.
Implications for action
The professional bodies of anaesthesiologists must be convinced about the validity and significance of the foregoing analysis and certain practical steps taken, as below: 
- The bodies should formally acknowledge the relevance of ergonomics to anaesthetic equipment and work-place design and also towards training and analysis of skills used
- They should have an adhoc committee and designated resource persons to relate ergonomics to anaesthesia
- Ergonomics should be incorporated into standards for anaesthetic equipment, a protocol of recommended design for work areas including operating theatres, recovery and intensive care areas, routine procedures and for training
- Research on ergonomics and anaesthesia should be encouraged by the suitable choice of projects for senior trainees and others likely to seek new areas for investigation
- Finally, anaesthesiologist being the end user should take active part in the design and modification of infrastructure and equipment by giving constructive feedback to the administrative bodies
- Automation of monitoring and record-keeping, use of services of non-anaesthesia personnel such as non-physician technicians may probably reduce the workload associated with the anaesthesia related tasks. 
| Summary|| |
Understanding human limitations early in the development of medical devices can reduce errors and avoid performance problems exacerbated by stress and fatigue. Using ergonomics in a design process can reduce the costs of procuring and maintaining products. Ergonomics can minimise the incidence of injury or long term malaise from poor working environments. An ergonomics task analysis can help identify key components of surgical skill, ensuring that students have affordable, appropriate, valid and reliable training. The way of visualising and documenting the interaction data with the help of the i-Flow Chart showed assets in communication at the interdisciplinary debriefing. There seems to be potential ergonomic benefits associated with recent advances in the field such as the use of ultrasound-guided regional anaesthesia. Prospective studies are needed to quantify the ergonomic or other benefits, to explore additional applications of this technology in the training and practice of ultrasound-guided procedure.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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