Simone Akerboom

Patient safety: latent risk factors

The person-centred analysis and prevention approach has long dominated proposals to improve patient safety in healthcare. In this approach, the focus is on the individual responsible for making an error. An alternative is the systems-centred approach, in which attention is paid to the organizational factors that create precursors for individual errors. This approach assumes that since humans are fallible, systems must be designed to prevent humans from making errors or to be tolerant to those errors. The questions raised by this approach might, for example, include asking why an individual had specific gaps in their knowledge, experience, or ability. The systems approach focuses on working conditions rather than on errors of individuals, as the likelihood of specific errors increases with unfavourable conditions. Since the factors that promote errors are not directly visible in the working environment, they are described as latent risk factors (LRFs). Safety failures in anaesthesia, in particular, and medicine, in general, result from multiple unfavourable LRFs, so we propose that effective interventions require that attention is paid to interactions between multiple factors and actors. Understanding how LRFs affect safety can enable us to design more effective control measures that will impact significantly on both individual performance and patient outcomes.

Job Stress in the Nursing Profession: The Influence of Organizational and Environmental Conditions and Job Characteristics.

The aim of the present study was to examine the influence of organizational and environmental work conditions on the job characteristics of nurses and on their health and well-being. The sample consisted of 807 registered nurses working in an academic hospital. The direct influence of work conditions on outcomes was examined. Mediation of job characteristics in the relationships between work conditions and outcomes was tested by means of regression analyses. The results indicated that job characteristics, such as demands and control, mediated the relationship between work conditions, such as work agreements and rewards, and outcomes. By managing organizational and environmental conditions of work, job characteristics can be altered, and these in their turn influence nurses’ job satisfaction and distress.

The detection of anisochrony in monaural and interaural sound sequences

Nakao and Axelrod (1976) and van Noorden (1975) showed that the threshold for discriminating an anisochronous duple rhythm (a series of clicks with a temporal offset on every other one) from an isochronous rhythm (no offset) is poorer when the clicks are presented alternately to the two ears than when they are presented to the same ears. Van Noorden reported that the difference between the thresholds in the alternating and nonalternating conditions varied with the tempo of the sequence. Nakao and Axelrod found invariance of this threshold difference with sequence speed. According to our quantification of temporal processing of interaural sequences, the latter result should be expected. We carried out five psychophysical experiments to establish interaural and monaural discrimination between isochronous and anisochronous rhythms. Across experiments, base time intervals of 60–720 msec were spanned. The main result was that we replicated the poorer discrimination for interaural sequences. This deterioration in discrimination was the same for all sequence speeds. It was also the case that the thresholds were almost constant up to a sound repetition rate of about 3 per second, but increased linearly with slower rates. This result supports evidence in the literature that temporal processing of sequences faster than about 3–4 sounds per second differs from temporal processing of slower sequences.

Assessing system failures in operating rooms and intensive care units

Background: The current awareness of the potential safety risks in healthcare environments has led to the development of largely reactive methods of systems analysis. Proactive methods are able to objectively detect structural shortcomings before mishaps and have been widely used in other high-risk industries. Methods: The Leiden Operating Theatre and Intensive Care Safety (LOTICS) scale was developed and evaluated with respect to factor structure and reliability of the scales. The survey was administered to the staff of operating rooms at two university hospitals, and intensive care units (ICUs) of one university hospital and one teaching hospital. The response rate varied between 40–47%. Data of 330 questionnaires were analysed. Safety aspects between the different groups were compared. Results: Factor analyses and tests for reliability resulted in nine subscales. To these scales another two were added making a total of 11. The reliability of the scales varied from 0.75 to 0.88. The results clearly showed differences between units (OR1, OR2, ICU1, ICU2) and staff. Conclusion: The results seem to justify the conclusion that the LOTICS scale can be used in both the operating room and ICU to gain insight into the system failures, in a relatively quick and reliable manner. Furthermore the LOTICS scale can be used to compare organisations to each other, monitor changes in patient safety, as well as monitor the effectiveness of the changes made to improve the level of patient safety.

Vibrotactual choice reaction time, tactile receptor systems and ideomotor compatibility

Abstract In most of the literature on human performance the results of an experiment by Leonard (1959) are quoted as the most outstanding example of perfect S-R-compatibility. In that experiment the fingertips were stimulated by a 50 Hz vibration; the vibrating armature had to be depressed and the reaction times of the right index finger were recorded. The reaction time was found not to increase with an increasing number of tactual choices. In experiment 1 of the present study, also applying 50 Hz vibrations, the reaction times of other fingers were also reported. In addition the response stimulus interval (RSI) was varied. Leonards results were not replicated: reaction time increased with the number of tactual choices at all levels of RSI. In experiment 2 the frequency and amplitude of vibration were systematically varied and it turned out that these variables could account for the differences between the results found. An increase in reaction time with the number of tactual choices was found with weak vibrations, but not with strong vibrations. The differences in reaction time patterns appeared to be caused by differences in tactile receptor systems (i.e. the non-Pacini versus the Pacinian system). It was concluded that the concept of S-R-compatibility did not cover the pattern of results but that the concept of ideomotor compatibility did.

Patient safety in the operating room: an intervention study on latent risk factors

BackgroundPatient safety is one of the greatest challenges in healthcare. In the operating room errors are frequent and often consequential. This article describes an approach to a successful implementation of a patient safety program in the operating room, focussing on latent risk factors that influence patient safety. We performed an intervention to improve these latent risk factors (LRFs) and increase awareness of patient safety issues amongst OR staff.MethodsLatent risk factors were studied using a validated questionnaire applied to the OR staff before and after an intervention. A pre-test/post-test control group design with repeated measures was used to evaluate the effects of the interventions. The staff from one operating room of an university hospital acted as the intervention group. Controls consisted of the staff of the operating room in another university hospital. The outcomes were the changes in LRF scores, perceived incident rate, and changes in incident reports between pre- and post-intervention.ResultsBased on pre-test scores and participants’ key concerns about organizational factors affecting patient safety in their department the intervention focused on the following LRFs: Material Resources, Training and Staffing Recourses. After the intervention, the intervention operating room - compared to the control operating room - reported significantly fewer problems on Material Resources and Staffing Resources and a significantly lower score on perceived incident rate. The contribution of technical factors to incident causation decreased significantly in the intervention group after the intervention.ConclusionThe change of state of latent risk factors can be measured using a patient safety questionnaire aimed at these factors. The change of the relevant risk factors (Material and Staffing resources) concurred with a decrease in perceived and reported incident rates in the relevant categories. We conclude that interventions aimed at unfavourable latent risk factors detected by a questionnaire focussed at these factors may contribute to the improvement of patient safety in the OR.

Auditory spatial alternation transforms auditory time.

Recent research has shown that a sequence of auditory events that is alternated between the ears is stretched out in auditory memory, as compared with nonalternating sequences. Although the stimulus-onset asynchronies (SOAs) of the interaural and monaural sequences were the same, the perceptual-onset asynchronies (POAs) differed by 24 msec. Because this result was only established for a restricted range of SOAs (125-250 msec), the present study tested a much larger range (40-2,130 msec). It turned out that the POA difference of 25 msec remained invariant over this whole range. Furthermore it was investigated how the angle of alternation affected the POA difference. It was found that (a) this difference increased linearly with increasing angular separation, and (b) the effects of SOA and angular separation on the POA difference were additive. The merits of six different attention-switching models were inspected to explain these results, but none of the models could describe the effects satisfactorily. We offer a new model, the space-time network, that copes not only with the present results but also explains several other studies reported in the literature.

The subjective tempo difference between interaural and monaural sequences as a function of sequence length

Previous research has demonstrated that the subjective tempo of sequences of clicks that alternate between ears is slower than that of nonalternating sequences. Although the stimulus onset asynchronies (SOAs) between the clicks are the same in both conditions, their perceptual onset asynchronies (POAs) differ by 25 msec at all SOA values between 40 and 2,130 msec. It has been suggested that this subjective tempo difference originates only after a few clicks have been processed. The present study shows this not to be the case: The POA difference between interaural and monaural click sequences could also be established with sequences comprising only a few clicks.

Perception of patient safety differs by clinical area and discipline

BACKGROUND Current thinking about patient safety emphasizes the relationship between organizational factors, that is, latent risk factors (LRFs) and patient safety. This study explores the influence of the operating theatre (OT), intensive care unit (ICU), and disciplines on ratings of LRFs. If we have an understanding of the contribution made by these factors, we can identify significant points from which we can promote a safe environment. METHODS Staff in four university hospitals were sent a survey relating to the state of LRFs, which included communication, planning and coordination, design, maintenance, equipment, teamwork, team instructions, housekeeping, situational awareness, hierarchy, and procedures. RESULTS The ICU staff had more favourable perceptions of training, communication, team instruction, and hierarchy. The OT staff had more favourable perceptions of technical LRFs. We found three profiles for disciplines: (i) anaesthetists and intensivists had more favourable perceptions of technical LRFs than surgeons and nurses. (ii) Anaesthetists, anaesthesia nurse-technicians, and recovery nurses had a poorer perception of non-technical skills. (iii) Anaesthesia nurse-technicians and recovery nurses had less favourable perceptions of procedures, housekeeping, and situational awareness than anaesthetists and intensivists. CONCLUSIONS As healthcare focuses its safety efforts towards system issues rather than towards the individual provider of care, attention has turned to organizational factors, known as LRFs. Understanding how LRFs affect safety should enable us to design more effective measures that will improve overall safety. Strategies for improving patient safety should be tailored specifically for various clinical areas and disciplines.

Does the octave illusion evoke the interaural tempo illusion

Many observers experience an auditory illusion when presented with a repeating dichotic chord (consisting of a 400-Hz and an 800-Hz tone) that alternates between the ears. Listeners state that they hear a sequence of single tones, alternating between a low and a high pitch and at the same time alternating between the ears. This is called the octave illusion (Deutsch, 1974, 1980). The aim of the present study was to measure objectively the subjective angle over which the illusory single tone alternates. Informal listening in our laboratory suggested that the subjective tones were not fully alternating over 180°. In order to measure the precise angular separation in the octave illusion, we made use of another illusion. If sounds are alternated between locations, the time intervals between the sounds appear to be longer, and when the angle of alternation becomes larger, the rate of the sequence appears to be slower (interaural tempo illusion). By means of a reaction-time technique, it is possible to infer the angle of alternation from the apparent rate. Listeners who indeed perceived the octave illusion had to perform the reaction-time task with the dichotic tone sequences (giving rise to the octave illusion) and several types of controltone sequences. The reaction times showed that the time intervals between the subjectively alternating tones in the octave illusion were not longer than the intervals between nonalternating tones. Hence, we can conclude that the output of the “what-where” mechanism is not operated on by the interaural tempo processor.