M. Susan Hallbeck

Sociotechnical systems analysis in health care: a research agenda

Given the complexity of healthcare and the ‘people’ nature of healthcare work and delivery, STSA (Sociotechnical Systems Analysis) research is needed to address the numerous quality of care problems observed across the world. This paper describes open STSA research areas, including workload management, physical, cognitive and macroergonomic issues of medical devices and health information technologies, STSA in transitions of care, STSA of patient-centered care, risk management and patient safety management, resilience, and feedback loops between event detection, reporting and analysis and system redesign.

Seating comfort and its relationship to spinal profile: A pilot study

Abstract Chair comfort is a subjective rating, comprising many factors which can be conceptually modelled. It was postulated that the overall comfort perceived by chair users is a function of the relative discomfort in various regions of the body and that the discomfort perceived in the lumbar region is a function of the spinal curvature. The results of two experiments are reported here. In the first experiment, five typical office chairs were evaluated in a field experiment using five subjects. The evaluation procedure used a general comfort rating scale, a body part discomfort rating scale, and a chair feature evaluation checklist. The results showed the body part discomfort ratings of the back regions to be critical in chair comfort. In the second experiment, three chairs were evaluated employing six subjects. The spinal posture of each subject was measured with a METRECOM ® digitizer while standing and seated in each chair type. The results indicate that the backrest curvature, and the thigh-trunk angle (included angle between the seat pan and the back rest) are critical for the overall chair comfort. The implications for the chair designer are discussed.

Crosstalk effect on surface electromyogram of the forearm flexors during a static grip task

The fraction of crosstalk was examined from the surface EMG signals collected from digit- and wrist-dedicated flexors with a blind signal separation (BSS) algorithm. Six participants performed static power grip tasks in a neutral posture at four different exertion levels of 25%, 50%, 75%, and 100% MVC. The signals were collected from the flexor digitorum superficialis, flexor digitorum profundus, flexor carpi radialis, palmaris longus, and flexor carpi ulnaris using a bipolar electrode configuration. The percentage of root mean square (RMS) was used as an amplitude-based index of crosstalk by normalizing the signals including crosstalk to those excluding crosstalk by the BSS algorithm for each %MVC exertion. The peak R(2) value of a cross-correlation function was also calculated as a correlation-based index of crosstalk for a group of forearm flexors by force level and algorithm application. The fraction of crosstalk ranged from 32% to 50% in the wrist-dedicated flexors and from 11% to 25% in the digit-dedicated flexors. Since surface EMG signals had such high levels of crosstalk, reduction methods like the BSS algorithm should be employed, as the BSS significantly reduced crosstalk in the forearm flexors 33% over all muscles and exertion levels. Thus, it is recommended that BSS be utilized to reduce crosstalk for the digit- and wrist-dedicated flexors during gripping tasks.

The effect of wrist position, angular velocity, and exertion direction on simultaneous maximal grip force and wrist torque under the isokinetic conditions

The objective of the study was to identify the effects of wrist position, force exertion direction, and angular velocity on simultaneous grip force and wrist torque under the isokinetic condition. Twenty-five male students participated in the study and the isokinetic wrist dynamometer was utilized to measure both forces from 901 of flexion to 901 of extension in the slow velocities of 101/s, 201/s, and 301/s. The results revealed that gripforce and wrist torque were larger around neutral and there was a passive force in the extremely extended wrist position. Wrist torque only was higher in the flexion direction but gripforce for both directions did not differ significantly. Both gripforce and wrist torque decreased when angular velocities increased and velocities could be classified into three groups, such as isometric, 5–201/s, over 251/s, according to the magnitude of force reduction. Finally, it was described that wrist positions, where maximal grip force and wrist torque occurred, were inconsistent and significant ranges of the wrist position including maximal forces were broad under the isokinetic condition of even slow velocities. r 2002 Elsevier Science B.V. All rights reserved.

Improving Medication Management Through the Redesign of the Hospital Code Cart Medication Drawer

Objective: This study utilized usability testing and human factors engineering (HFE) principles to create efficient code cart medication drawer modifications to improve code blue medical emergency (code) medication management. Background: Effective access to medications during a code is a key component in delivering optimal care and has been found to be a major problem among health care organizations; however, little research has been conducted to improve the efficiency of medication management during a code. Method: A total of 26 health care professionals (13 pharmacists and 13 nurses) were asked to locate items within a code cart medication drawer during two independent simulated code scenarios alternately using either a baseline medication drawer (control; Drawer 1) or a prototype medication drawer (prototype; Drawer 2), which was developed using HFE principles and usability testing. Overall medication retrieval time, wasteful actions, and survey responses were recorded. Results: Drawer 2 had significantly faster trial completion times (p = .005) and fewer wasteful actions (p < .001) compared to Drawer 1. Participant survey results rated Drawer 2 (prototype) significantly higher (more favorable) for medication drawer visibility (p < .001), usability (p = .011), and organization (p < .001) compared to Drawer 1 (baseline). Conclusion: The HFE redesign concepts incorporated into Drawer 2 (consisting of visibility, grouping, and organization) produced successful, low-cost, and generalizable modifications that can improve patient care. Application: The findings demonstrate that HFE and usability applied to code cart design are effective, are customizable, and can affect patient safety by saving valuable time and reducing wasted motions (including errors) during code situations.

Intraoperative “Micro Breaks” With Targeted Stretching Enhance Surgeon Physical Function and Mental Focus: A Multicenter Cohort Study

Objective: The aim of this study was to investigate the effect of intraoperative targeted stretching micro breaks (TSMBs) on the experienced pain and fatigue, physical functions, and mental focus of surgeons. Background: Surgeons are routinely subject to mental and physical stresses through the course of their work in the operating room. One of the factors most contributory to the shortening of a surgeons career is work-related pain and its effects on patient safety and personal relationships. Methods: Surgeons and operating room staff from 4 medical centers rated pain/fatigue, physical, and mental performance using validated scales during 2 operative days: 1 day without implementing TSMB, the other including standardized (1.5 to 2 minutes) guided TSMB at appropriate 20 to 40-minute intervals throughout each case. Case type and duration were recorded as were surgeon pain data before and after each procedure and at the end of the surgical day. Individual body part pre/postdiscomfort difference was modeled, controlling for clinical center. Random coefficient mixed models accounted for surgeon variability. Results: Sixty-six participants (69% men, 31% women; mean 47 years) completed 193 “non-TSMB” and 148 “TSMB” procedures. Forty-seven percent of surgeons were concerned that musculoskeletal pain may shorten their career. TSMB improved surgeon postprocedure pain scores in the neck, lower back, shoulders, upper back, wrists/hands, knees, and ankles. Operative duration did not differ (P> 0.05). Improved pain scores with TSMB were statistically equivalent (P > 0.05) for laparoscopic and open procedures. Surgeons perceived improvements in physical performance (57%) and mental focus (38%); 87% of respondents planned to continue TSMB. Conclusions: Many surgeons are concerned about career-ending or limiting musculoskeletal pain. Intraoperative TSMB may represent a practical, effective means to reduce surgeon pain, enhance performance, and increase mental focus without extending operative time.

Supracutaneous vibrotactile perception threshold at various non-glabrous body loci

Researchers at the University of Nebraska–Lincoln are currently designing a wearable/portable neutron detector. As an alerting mechanism, the device will transmit vibration to the wearers skin in the presence of hazardous levels of neutron radiation. The present study was designed to help in the ergonomically correct body placement of the neutron detection device while providing numerical values for vibratory thresholds at the surface of various non-glabrous body loci. The aim of the study was to investigate the underlying effects of locus stimulated, amount of subcutaneous fat around a specific body site and gender on low frequency vibration thresholds. Thirty-six participants, who were categorised by both dichotomous body fat group (high or low) and gender, were tested at 24 loci orthogonally located around six body sites: head; neck; upper arm; wrist; waist; ankle. The results indicated that frequency threshold depends significantly on the locus stimulated (p=0.001). The nape of the neck had the greatest sensitivity to low frequency stimulations, while the loci around the waist were least sensitive. Also, body fat significantly affected ability to perceive vibratory stimuli (p=0.048), with the mean frequency threshold of the low body fat group lower than that of the high body fat group. There was no statistical difference in thresholds with gender.

Ergonomics of novices and experts during simulated endotracheal intubation

Endotracheal Intubation (ETI) is an airway procedure commonly used to secure the airway for a variety of medical conditions. Proficiency in ETI procedures requires significant clinical experience and insufficient data currently exists describing the physical ergonomics of successful direct laryngoscopy. The research objectives of this study were to examine how ETI time, error and practitioner biomechanics varied among clinical experience levels and hospital bed heights. The participant population included novice and expert personnel, differentiated by their exposure to ETI procedures. Participants used a standard laryngoscope and blade to perform ETI trials on an airway manikin trainer at predesigned hospital bed heights. Participants were evaluated based on ETI time and accuracy, as well as wrist postures and muscle utilization. Hospital bed height did not affect task completion time, error rates or muscle utilization. Expert participants exhibited less ulnar deviation and forearm supination during task trials, as well as a higher utilization of the bicep brachii and anterior deltoid muscles. Expert grasped instrumentation differently, requiring less wrist manipulation required to achieve ideal instrument positions. By encouraging ergonomic best-practices in hand and arm postures during ETI training, the opportunity exists to improve patient safety and reduce the learning curve associated with ETI procedures.

A hand-held neutron detection sensor system

In this paper, a hand-held neutron radiation sensor application is described. The sensor system utilizes a new class of boron-carbide diode that interacts with incoming neutrons. To interface with the boron-carbide diode an integrated front-end is designed in a 1.5mum standard CMOS technology. With the diode and front-end microchip, a hand-held neutron detection system was realized with an embedded microcontroller for realtime processing. The hand-held detector operation was then tested with a plutonium-beryllium neutron source. Testing results confirm the validity of the approach and the functionality of the design

Ergonomic evaluation of laparoendoscopic single-site surgery ports in a validated laparoscopic training model

Although laparoendoscopic single-site surgery (LESS) is feasible among expert laparoscopic surgeons, it poses many technical challenges not seen in conventional laparoscopy (CL). Recent technological advancements in single-incision instrumentation have created more interest and widespread usage of LESS. However, neither LESS nor its novel instrumentation have been thoroughly studied or evaluated using human factors and ergonomics techniques. Consequently, the aim of this study was to compare the physical performance of LESS to CL using a standardized task. Wrist and elbow angular movements, range of motion and physical discomfort were assessed for 24 novice participants. There were no significant differences for physical comfort/discomfort ratings or elbow and wrist flexion/extension range of motion between CL and LESS. However, wrist radial/ulnar range of motion was significantly greater in LESS compared to CL (p < 0.05). Additionally, wrist radial/ ulnar range of motion was significantly greater using the SILS Port compared to the GelPOINT (p < 0.05). Although further investigation is needed, LESS resulted in greater wrist deviation and range of motion due to the close proximity of the instruments, restrictive nature of the single-port devices, and the need to achieve adequate instrument triangulation and visualization.