Health and safety Health Psychology
Statistics • Government data reveal that accidental injury is~ • 1. · the fourth most frequent cause of death in the American population as a whole. • 2. · The leading cause of death of individuals under age 45. • 3. · Responsible for over half of all deaths of children and adolescents (Cataldo et al., 1986; Haggerty, 1986; WaIler, 1987).
Definition • Pheasant (1991) defines an accident as “ an unplanned unforeseen or uncontrolled event – generally one that has unhappy consequences”.
Road accidents • During 1999 there were just over 235,000 accidents causing personal injury, which caused 320,000 casualties including 3,600 deaths. This actually shows a marked improvement over the last twenty years, as deaths and serious injuries have reduced by 36 per cent and 48 per cent respectively since 1981 • (DETR, 1999).
Accidents in the home • Around 4,300 people are killed each year in home and garden accidents, and about 170,000 suffered serious injuries that required inpatient treatment in hospital. Home accidents also led to 2.84 million visits to accident and emergency departments.
Accidents at work • Surveys indicate that about 1.5 million people each year are hurt at work and treated in casualty departments. Many of the injuries are minor and so are not reported. In 1998/9 there were just under 53,000 major injuries reported, of which 24,000 were to members of the public (R0SPA, 2001 a).
CAUSES OF ACCIDENTS • In some respects all accidents are unique, but it is also possible to see some common contributory causes. Reason (2000) says that the problem of human error can be viewed in two ways: the person approach, and the system approach. Each way has its own model of the causes of error and suggestions of what is to be done about it.
CAUSES OF ACCIDENTS • The example below of giving the wrong medicine highlights these two models.
The Wrong Medicine • On the afternoon of January 4th 2001, a day case patient at the Queens Medical Centre (QMC) in Nottingham turned up for his chemotherapy treatment. Under the supervision of a Specialist Registrar, a Senior House Doctor correctly gave the patient a drug (Cytosine) directly into the spine.
The Wrong Medicine • A second drug (Vincristine) was then also administered by the same route. Unfortunately, this drug should have been given intravenously, and despite the efforts of the medical staff the 19-year-old patient died.
The Wrong Medicine • How could this happen? How could two experienced, specialist doctors make what appears to outsiders to be such a basic error? The inquiry into the accident (D0H, 2001 d) highlights how professional mistakes (personal causes of error) and the procedures and equipment (system causes) contributed to the death. It was already known that there was a danger of giving Vincristine into the spine because it had happened before.
The Wrong Medicine • As a result it was part of good practice at the QMC to give the two treatments — one into the spine and one into a vein — on different days, but this procedure was not always followed, especially when patients had a history of missing appointments. Also, the manufacturer of Vincristine provided labels to be attached to the syringes which said ‘Not for intrathecal use — For intravenous use only. However the QMC staff did not use these labels because they believed they had the potential to confuse people.
The Wrong Medicine • The inquiry also noted that the syringes for both injections looked very similar and that the labels were both in black type.
Unsafe behaviours / systems • Accidents are caused by either: • Unsafe behaviours or • Unsafe systems
Roberts and Holly (1996) • Roberts and Holly (1996) list the basic causes of accidents in hospital settings: • Inadequate work standards: through a lack of training and supervision. • Inadequate equipment or maintenance of equipment • Abuse or misuse of equipment, or failure to check equipment. • Lack of knowledge (for example in not being able to use equipment correctly.
Roberts and Holly (1996) • Inadequate physical or mental capacity to do the required job. • Mental or physical stress • Improper motivation (e.g. Dr Shipman)
Deskilling • A source of error in the relationship between operators and machines is the deskilling of the workers. Bainbridge (1987) referred to this as the irony of automation. She pointed out that designers view human operators as unreliable and inefficient, and try to replace them wherever possible with automated devices. Yet this policy often leads directly to an increased number of errors and accidents.
Deskilling • The paralysis of the London Ambulance Service, a direct result of the introduction of an automated emergency call routing system in 1993, was a classic example of how this type of problem happens. There are two ironies here: the first is that many mistakes come from the designer’s initial errors — systems are introduced which have not been properly worked out and which are actually unable to do what is required of them. Second, as Bainbridge points out, designers still leave people to do the difficult tasks, which cannot be automated so easily.
Cognitive overload • The study of selective attention highlights some limitations on our ability to process information. An example of this problem was reported by Barber (1988), in a description of an aircraft accident in the area of Zagreb, which was then part of Yugoslavia.
Cognitive overload • A British Airways Trident collided with a DC-9 of Inex Adria Airways, resulting in the loss of 176 lives. One of the factors identified as leading to the collision was the cognitive overload of the air traffic controller responsible for the sector the planes were flying in.
Cognitive overload • At the time of the accident the controller’s assistant was missing, there were eleven aircraft in his sector, he was in simultaneous radio communication with four other aircraft, and he was taking part in a telephone conversation with Belgrade concerning two further aircraft.
Cognitive overload • The controller had received very short notice of the arrival of the DC-9 into his sector and it appears that the short notice and the overload of information contributed to the final error. Nevertheless, he was prosecuted and jailed.
Cognitive overload • This is a graphic illustration of the limitations of our information processing capacities, and shows that the public response to disasters is often to blame individuals, when it is the systems within which the individuals are working which are actually at fault.
Equipment design • An illustration of the problem of equipment design occurred during World War 11(1939—45), and it came about because the US air force had concentrated on training pilots to fly aircraft rather than designing aircraft that could be flown by pilots. They discovered, however, that even very experienced pilots were prone to make errors with the poorly designed control systems.
Equipment design • For example, similar looking controls operating the landing gear and the steering flaps on some B-25 bombers were placed next to each other. The unfortunate consequence of this was that several B-25s were brought into land without the landing gear in place, and so landed on their bellies.
Equipment design • The pilots believed that they had activated the landing gear, but in fact they had just steered the plane (Mark, Warm and Huston, 1987). Observations like this have led to the development of aircraft controls that more nearly match the capabilities of pilots.
Causes of accidents • Most accidents have multiple causes, though we can divide many of them into two basic categories: • 1. Individual errors (unsafe behaviours) • 2. Organisational errors (unsafe systems)
Causes of accidents • Reason (1990), in his discussion of human error presented a series of case studies of major disasters. In each disaster, a situation was created over a number of months or years, where the systems introduced or neglected by management finally produced a major incident. The incident itself was triggered by the action of one or two individuals and it was these individuals who inevitably got the public blame while the organisation remained relatively unscathed.
Causes of accidents • In his description of the Herald of Free Enterprise ferry disaster Reason (1990) identified ten factors that contributed to the sinking of the ship. He attributed all of them to bad management decisions and design problems, yet it was three sailors who were punished while the management of the ferry owners (P&O) avoided any sanctions.
Chain of events and active failures Contributing conditions and latent failures The Herald is docked at No. 12 berth in Zeebrugge’s inner harbour, and is loading passengers and vehicles before making the crossing to Dover. This berth is not capable of loading both car docks [E and G] at the same time, having only a single ramp. Due to high water spring tides, the ramp could not be elevated sufficiently to reach L dock. To achieve this, it was necessary to trim the ship nosedown by filling trim ballast tanks Nos. 14 and 3. Normal practice was Lu start filling No. 14 tank 2 hours before arrival. (System failure) At 18.05 on 6 March 1987, The Herald goes astern from the berth, turns to starboard, and proceeds to sea with both her inner and outer bow doors fully open The most immediate cause is that the assistant boson (whose job it was to close the doors) was asleep in his cabin, having just been relieved from maintenance and cleaning duties.(Supervisory failure and unsuitable rostering)The boson, his immediate superior, was the last man to leave G dock. He noticed that the bow doors were still open, but did not close them, since he did not see that as part of his duties.(Management failure) Herald of Free Enterprise
Chain of events and active failures Contributing conditions and latent failures Chief officer checks that there are no passengers on G dock, and thinks he sees assistant boson going to close doors (though testimony is confused on this point). The chief officer, responsible for ensuring door closure, was also required (by company orders) to be on the bridge 15 minutes before sailing time.(Management failure)Because of delays at Dover, there was great pressure on crews to sail early. Memo from operations manager: ‘Put pressures on your first officer if you don't think he’s moving fast enough… sailing late out of Zeebrugge isn't on. It's 15 minutes early for us.’(Management failure)Company standing orders (ambiguously worded) appear to call for negative reporting only. If not told otherwise, the master should assume that all is well. Chief officer did not make a report, nor did the master ask him For one.(Management failure) Herald of Free Enterprise
Chain of events and active failures Contributing conditions and latent failures On leaving harbour, master increases speed. Water enters open bow doors and Floods into C deck At around 18.27, Herald capsizes to port. Despite repeated requests from the masters to the management, no bow door indicators wore available on the bridge, and the master was unaware that he had sailed with bow doors open. Estimated cost of indicators was £400-500.(Management failure) Ship had chronic list to port. (Management and technical failure)Scuppers inadequate to void water from flooded G deck. (Design and maintenance failure)Top-heavy design of The Herald and other ‘ro ro' ships in its class was inherently unsafe.(Design failure)Source: Reason, 1990 Herald of Free Enterprise
Human error • Riggio (1990) identified four types of error that can lead to accidents: • · 1 Errors of omission: failing to carry out a task; for example, not closing the bow doors on the ferry in Zeebrugge harbour • · 2 Errors of commission: making an incorrect action, for example, a health worker giving someone the wrong medicine • ·3 Timing errors: working too quickly, working too slowly • ·4 Sequence errors: doing things in the wrong order
The negative consequences to an individual of reporting a personal error or accident include: • · · time lost • · · feeling guilty • · · admitting mistakes • · · possible disciplinary action • · · possible lost confidence of colleagues • · · making a mountain out of molehill.
The problems for management of receiving an accident report include: • · · having a written record of the event which increases the danger of litigation • · · increased need for action by management • · · increased need for investment in people Or equipment • · · responsibility is shifted from the worker to the organisation.
Factors affectingorganisational error • 1. · the selection of inappropriate staff • 2. · poor working procedure • 3. · duty rotas that lead to fatigue • 4. · an organisational climate that creates poor morale • 5. · inadequate equipment for the task • 6. · inadequate levels of training.
Factors affecting individual errorI Substance and alcohol abuse • The most commonly cited cause of accidents is alcohol or substance abuse. When chemicals impair our judgement we are more likely to underestimate the risks of a situation, and overestimate our ability to deal with it. A study of over 500 people attending accident and emergency departments in Scotland examined levels of alcohol (Simpson et a/. 2001).
Factors affecting individual errorI Substance and alcohol abuse • About 25 per cent of the attendees showed signs of alcohol. It was especially noticeable in people attending for reasons of self-harm (95 per cent), collapse (47 per cent) assault (50 per cent), and in those who were subsequently admitted to the hospital (50 per cent). These figures suggest that alcohol might well be a factor in a range of accidents that lead to serious injury. A less well researched area is the effect of prescription drugs on performance.
Factors affecting individual errorI Substance and alcohol abuse • In Britain the Department of Transport (1996) carried out an analysis of data on road traffic accidents in which one or more of the drivers involved either failed or refused a breath or blood test. In 1996 there were 10,850 drink-drive accidents including 540 deaths. Pedestrians who are killed in road accidents are also likely to have been drinking.
Factors affecting individual errorI Substance and alcohol abuse • In an earlier report (Department of Transport, 1992), it was estimated that about half of pedestrians aged between 16 and 60 killed in road accidents had more alcohol in their bloodstream than the legal drink-drive limit. This fact is certainly supported in any driver’s experience of travelling through urban areas after pub closing time at night.
Factors affecting individual errorI Substance and alcohol abuse • Studies conducted in a number of countries indicate that alcohol is implicated in many attendances at hospital accident and emergency departments (Cherpitel, 1993; Waller et al., 1998). Williams et al. (1994) reported that 50% of adults admitted to a hospital surgery unit with a head injury were obviously drunk. Alcohol has been shown to play a significant role in deaths from falls, fires, industrial accidents and deaths from drowning (Eckhardt et al., 1981; Plueckhan, 1982; Tether and Harrison, 1986).
Factors affecting individual errorI Substance and alcohol abuse • Drunk driving is a major cause of death in the United States: about one-half of the nearly 40,000 deaths each year in automobile accidents are associated with alcohol use; fortunately, the number of motor vehicle deaths and those related to alcohol use have declined greatly since the early 1980s (Tolchin, 1993). Consuming alcohol impairs cognitive, perceptual, and motor performance for several hours; particularly the first 2 or 3 hours after drinks are consumed.
Factors affecting individual errorI Substance and alcohol abuse • The degree of impairment individuals experience can vary widely from one person to the next and depends on the rate of drinking and the person’s weight. The table gives the average impairment for driving—but for some people, one or two drinks may be too many to drive safely.
Factors affecting individual errorI Substance and alcohol abuse • Barbone et aI. (1998) looked at the medical records of drivers in Scotland involved in their first car accident over a three-year period to identify how many had been prescribed psychoactive drugs such as tranquillisers (for example, benzodiazepines) and antidepressants. There were 19,400 drivers involved in accidents in that period, of which over 1,700 were on some form of psychoactive medication, most commonly benzodiazepines.
Factors affecting individual errorI Substance and alcohol abuse • They concluded that users of benzodiazepines had a 60 per cent higher risk of having a first traffic accident and should be advised not to drive.
Factors affecting individual errorLack of sleep • It is a robust finding from sleep research that sleep deprivation affects people so that they (a) make more errors, and (b) need longer to complete a task (Asken, 1983). One particular area of concern is sleep-related vehicle accidents (SRVAs). A substantial survey of 4,600 UK drivers found that 29 per cent admitted to having felt close to falling asleep at the wheel during the previous 12 months (Maycock, 1996). Sleepiness is brought on by long, undemanding, monotonous driving, such as on a motorway.
Factors affecting individual errorLack of sleep • It is also, not surprisingly, affected by the time of day, as our bodily rhythms affect our level of arousal and alertness. One of the problems for drivers who are feeling sleepy is they are often not aware of dropping off for a few seconds. It is a general finding from sleep research that people who are woken within a minute or two of falling asleep commonly deny having been asleep (Home and Reyner, 1999).
Factors affecting individual errorAccident proneness • This is controversial, since it stigmatises some individuals, though there is some research that suggests accident proneness can be identified. Jones and Wuebker (1988) describe how a personnel inventory can be used to predict a number of accident-related events. Using the questionnaire they were able to identity high-risk individuals on the basis of their attitudes and personality, and to place them in less hazardous positions, or place them on special safety training programmes.