Technological change and economic pressure are moving medical practice out of hospitals and into the home or other alternative health care settings. Patients with chronic conditions may be able to move out of the hospital by using infusion devices that support self-administration of drugs. For example, diabetics may use these infusion devices for insulin therapy, and women with high-risk pregnancies may use these devices to self-administer drugs that control preterm labor.
These changes are made possible by changes in medical technology - automated infusion devices. However, if these new computer-based devices are designed poorly from a user-centered point of view (Norman, 1988), they can induce erroneous actions. Previous studies of computer-based medical devices in critical care medicine have found that computer-based medical devices often exhibit a variety of classic human-computer interaction (HCI) deficiencies, such as poor feedback about device state and behavior; complex and ambiguous sequences of operation; multiple, poorly distinguished modes; and ambiguous alarms (Cook, Potter, Woods, & McDonald, 1991; Cook & Woods, 1996 [this issue]; Moll van Charante, Cook, Woods, Yue, & Howie, 1993). These deficiencies are important because they have been shown to increase the potential for erroneous actions and to impair the physician's ability to detect and recover from errors (e.g., Cook, Woods, & Howie, 1992).
In this paper we extend the results of those studies of physician interaction with computer-based medical devices to the home health care context. We examined how nurses and patient-operators interact with a computer-based infusion device used for terbutaline infusion to treat preterm labor in women experiencing high-risk pregnancies. This device was originally used in insulin administration for diabetics, but it was adapted to assist in the control of preterm labor.
The purpose of the study was to investigate how nurses and patient-operators used the device to control preterm labor and to identify characteristics of the device that make its operation difficult and prone to error. Our investigations also focused on how the perinatal nurses developed strategies to work around or guard against the HCI deficiencies in the device (Cook & Woods, 1996). These adaptations or tailoring strategies occurred because patients and their nurse caregivers were responsible for achieving their own goals: for the patient to remain at home during a difficult pregnancy and to have a successful delivery as close to term as possible, regardless of the design of the computer-based device.
Three kinds of investigations were carried out: (a) interviews with nurses about how they used the device and about how patient-operators used the device; (b) "bench" tests that explored how the device behaved, how the displays represented those states and activities, and the control sequences needed to interact with the device across a range of tasks and contexts relevant to terbutaline therapy for preterm labor; and (c) observations of nurses programming the device to accomplish different tasks.
This paper describes three aspects of user-device interaction: (a) the HCI deficiencies in the device as related to this context of use, (b) how the device characteristics increase the potential for error, and (c) the tailoring strategies developed by users to insulate themselves from failure.
THE CONTEXT: TERBUTALINE THERAPY
The focus of this investigation was the use of a computer-based infusion pump for terbutaline therapy with pregnant women experiencing pre-term labor. Terbutaline is a member of the beta-adrenergic drug class and affects adrenergic receptor sites. The drug interacts with the beta receptor sites leading to uterine relaxation.
Control of preterm labor requires therapy 24 h/day, and patient-operators may need to interact with the infusion pump at any time (e. …