Noise in the ICU

Objective The growing number of technical devices in ICUs makes noise exposure a major stressor. The purpose of this study was to assess noise levels during routine operation in our ICU.Design Our ICU is an open ward with four rooms, constructed in the 1960s. During the study period, 4 patients were in the controlled room and were treated by 4 nurses during the day and by 2 at night. A-weighted sound pressure levels (SPL) were measured continuously for 2 days and nights. Also measured were the alarms of various appliances. For gross overall evaluation it is customary to state the L_eq, i.e. the energy-averaged level during measurement. The annoyance caused by noise depends more on rare events of high intensity. Therefore, the distribution of SPL values (L_n) over time was also analysed.Results SPL was roughly the same during the day and at night, with L_eq between 60–65 dB(A) and peaks up to 96 dB(A). Most alarms reach an SPL of 60–70 dB(A), but some exceed 80 dB(A). During teaching rounds L_eq exceeds 65 dB(A).Conclusion During the day and at night SPL always surpasses the permissible noise exposure for 24 h of 45 db(A) recommended by the US Environmental Protection Agency. Alarms cause the most irritating noise. Hospital management should pay attention to internal noise, and SPL should be measured routinely.     

Arrhythmias in patients with acute coronary syndrome in the first 24 hours of hospitalization

Objectives

In patients with acute coronary syndrome (ACS), we sought to: 1) describe arrhythmias during hospitalization, 2) explore the association between arrhythmias and patient outcomes, and 3) explore predictors of the occurrence of arrhythmias.

Methods

In a prospective sub-study of the IMMEDIATE AIM study, we analyzed electrocardiographic (ECG) data from 278 patients with ACS. On emergency department admission, a Holter recorder was attached for continuous 12-lead ECG monitoring.

Results

Approximately 22% of patients had more than 50 premature ventricular contractions (PVCs) per hour. Non-sustained ventricular tachycardia (VT) occurred in 15% of patients. Very few patients (≤1%) had a malignant arrhythmia (sustained VT, asystole, torsade de pointes, or ventricular fibrillation). Only more than 50 PVCs/hour independently predicted an increased length of stay (p < .0001). No arrhythmias predicted mortality. Age greater than 65 years and a final diagnosis of acute myocardial infarction independently predicted more than 50 PVCs per hour (p = .0004).

Conclusions

Patients with ACS seem to have fewer serious arrhythmias today, which may have implications for the appropriate use of continuous ECG monitoring.     

Sensor technologies aiming at fall prevention in institutionalized old adults: A synthesis of current knowledge

BackgroundFalls are a serious health problem in old adults especially in nursing home residents and hospitalized patients. To prevent elderly from falling, sensors have been increasingly used in intramural care settings. However, there is no clear overview of the current used technologies and their results in fall prevention.ObjectivesThe present study reviews sensor systems that prevent falls in geriatric patients living in an intramural setting and describe fall rates, fall-related injuries, false alarms, and user experience associated with such systems.MethodsWe conducted a systematic search for studies that used sensor technologies with the aim to prevent falls in institutionalized geriatric patients.ResultsA total of 12 studies met the search criteria. Three randomized clinical trials reported no reductions in fall rate but three before–after studies reported significant reductions of 2.4–37 falls per 1000 patient days. Although there was up to 77% reduction in fall-related injuries and there was relatively low, 16%, rate of false alarms, the current data are inconsistent whether current sensor technologies are effective in reducing the number of falls in institutionalized geriatric patients. The occurrence of false alarms (16%) was too high to maintain full attention of the nursing staff. Additionally including the users opinion and demands in developing and introducing sensor systems into intramural care settings seems to be required to make an intervention successful.ConclusionThe evidence is inconsistent whether the current sensor systems can prevent falls and fall-related injuries in institutionalized elderly. Further research should focus more comprehensively on user requirements and effective ways using intelligent alarms.     

医用气体系统的安全设计

医用气体系统的安全关系到患者的生命安全,在医院的治疗和抢救过程中发挥着至关重要的作用.文章从医用气体的气源系统、管道系统、终端系统、报警系统等几个方面分析和论述了在医用气体系统中如何设计以保证系统安全运行.     

Intensive care unit nurses' information needs and recommendations for integrated displays to improve nurses' situation awareness

Objective

Fatal errors can occur in intensive care units (ICUs). Researchers claim that information integration at the bedside may improve nurses'' situation awareness (SA) of patients and decrease errors. However, it is unclear which information should be integrated and in what form. Our research uses the theory of SA to analyze the type of tasks, and their associated information gaps. We aimed to provide recommendations for integrated, consolidated information displays to improve nurses'' SA.

Materials and Methods

Systematic observations methods were used to follow 19 ICU nurses for 38 hours in 3 clinical practice settings. Storyboard methods and concept mapping helped to categorize the observed tasks, the associated information needs, and the information gaps of the most frequent tasks by SA level. Consensus and discussion of the research team was used to propose recommendations to improve information displays at the bedside based on information deficits.

Results

Nurses performed 46 different tasks at a rate of 23.4 tasks per hour. The information needed to perform the most common tasks was often inaccessible, difficult to see at a distance or located on multiple monitoring devices. Current devices at the ICU bedside do not adequately support a nurse''s information-gathering activities. Medication management was the most frequent category of tasks.

Discussion

Information gaps were present at all levels of SA and across most of the tasks. Using a theoretical model to understand information gaps can aid in designing functional requirements.

Conclusion

Integrated information that enhances nurses'' Situation Awareness may decrease errors and improve patient safety in the future.     

Cognitive psychology and the design of alarm sounds

One of the less desirable features about technological advances in medicine is that individuals working with sophisticated monitoring equipment are often bombarded by warning sounds and signals. However, there are some basic cognitive psychological principles which suggest that the over-use of auditory warnings in such circumstances may be counter-productive. This review highlights some of these principles, arguing that future systems should place more emphasis upon cognitive capabilities and predispositions in their design. Upcoming alarms standards where issues such as the number of alarms, their recognizability, and the principle of ‘urgency mapping’ are discussed with relation to the cognitive psychology of sound.     

Influence of Pulse Oximeter Settings on the Frequency of Alarms and Detection of Hypoxemia

Objective. The potential benefit of a reduced frequency of false pulse oximeter low oxyhemoglobin saturation (SpO₂) alarms is that the attention of personnel is only directed to patients who experience hypoxemia. The present study was undertaken to better understand the effects of different settings of the pulse oximeter on false (artifact) and true (hypoxemia) alarms. Methods. Using the original SpO₂ data of 200 postoperative patients, we calculated off-line the effects of five methods (artifact rejection, alarm delay (2–44 s, 2 s increments), averaging (10–90 s), median filtering (10–90 s) and decreasing the alarm limit from 90% to 85%) on the number of (true- and false) alarms. Results. 830 episodes of hypoxemia (SpO₂ 90%) and 73 episodes of severe hypoxemia (SpO₂ 85%) occurred. With a SpO₂ alarm limit of 90%, the alarm was triggered 1535 times (830 true, 705 false). Artifact rejection reduced alarms by almost 50%. An alarm delay of 6 s or an averaging or median filtering epoch of 10 s resulted in an alarm reduction of almost 50%. No differences were found in the reduction of alarms between averaging and median filtering. Changing the alarm limit to 85% reduced the number of alarms by 82%. A similar reduction of alarms was obtained with either an alarm delay of 18 s or an averaging or median filtering epoch of 42 s. However, an alarm limit of 85% reduced the number of false alarms less than the other three algorithms (p < 0.01). Conclusions. The data from the present study suggest that in order to effectively suppress false alarms caused by pulse oximeter artifacts, it may be preferable to use a longer filtering epoch of approximately 40 s, rather than to decrease the lower alarm limit.