| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1 Department of Radiology, Brigham and Women's Hospital, 75 Francis St., Boston,
MA 02115.
2 Present address: Department of Radiology, Hospital of St. Raphael, 1450 Chapel
St., New Haven, CT 06511.
Received October 1, 2001;
accepted after revision April 2, 2002.
Address correspondence to D. B. Nuñez, Jr.
Abstract
 Top Abstract IntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
MATERIALS AND METHODS. We designed a data collection form to record consecutive periods of patient scanning and periods between patients when the CT scanner was not in use. The contributing factors for each idle period were identified and logged according to an entry system previously decided in consensus. Data were collected continuously for 11 days. The factors we identified for measurement were no request for scanning, preventive maintenance, equipment failure, technologist unavailable, room cleaning and preparation, patient preparation for abdominal CT, patient undergoing other tests, transportation delays, pending laboratory workup, and miscellaneous factors. The time attributed to the most prevalent factors was also grouped into four 6-hr periods corresponding to our department's shifts.
RESULTS. The scanner was idle 73% of the total study time. The chief contributing factors to lack of use were having no patients to scan, patient undergoing preparation, and transportation delays, which accounted for 38.5%, 31%, and 11.7% of the aggregate idle time, respectively. The 6-hr periods of least use were the 7:00 A.M.—1:00 P.M. and the 1:00 A.M.—7:00 A.M. shifts, which accounted for 17% and 19% of idle time, respectively.
CONCLUSION. Dedicated emergency department CT scanners can have significant daily periods of consistent lack of use. The idle time can be reduced by identifying patterns of referral time and correcting specific operational delays.
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
Many emergency centers are now equipped with CT scanners that provide immediate access for acutely ill patients. Despite an unquestionable growing demand for CT in the emergency department, it had been our untested observation that a CT unit with a 24-hr dedication to emergency patients may remain idle for significant periods. Our objective was to quantify the factors that contribute to lack of use of a dedicated CT scanner in the emergency department of a major academic medical center and to identify opportunities for performance improvement across institutional CT operations.
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
|
Two broad categories were defined for the idle time: no CT requisition pending (no patient to scan) and having a pending requisition but not scanning for reasons other than having another patient in the CT suite. In the latter category, one of nine factors was logged as the contributor to idle time. To avoid significant variability in the registration of data, the operational factors to be quantified were individually defined by consensus of the group of physicians and CT technologists. Additionally, an in-service trial of possible scenarios was presented to the personnel directly in charge of logging the data. Preventive maintenance, equipment failure, technologist not available, and room preparation were defined as prevailing factors for CT unavailability. Patient undergoing preparation, patient undergoing other diagnostic tests, patient waiting for transportation, pending laboratory workup, and miscellaneous factors were logged as contributors only when the CT unit was available for scanning. We ensured that during the study period only our four dedicated CT technologists were covering all shifts so that entry of data would be consistent.
If more than one factor contributed separately to idle time between the scanning of two patients, these factors were logged as separate and consecutive entries. For example, if the scanner was idled waiting for a patient to complete another test and, on completion, additional idle time was generated by delay in patient transport to CT, the two components were entered consecutively. If two or more factors were concurrent, the one selected as the more significant contributor was chosen for the entry. For example, if a patient was waiting to complete oral contrast preparation for CT but concurrently the CT unit was inoperative because of maintenance, only the latter was entered. With this model, only one factor was used to account for lack of use in any given unit of time, pursuant to our preestablished criteria for selecting the primary contributing factor.
In addition, the time contributed by the most prevalent factors and the total number of patients studied were stratified into four periods: 7:00 A.M.—1:00 P.M. (period A), 1:00 P.M.—7:00 P.M. (period B), 7:00 P.M.—1:00 A.M. (period C), and 1:00 A.M.—7:00 A.M. (period D). We chose these periods to match the scheduling shifts used in our primary radiology department.
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
The idle time caused by each factor and its relative contribution to the total idle time are shown in Table 1. We found three principal reasons for lack of scanner usage: no request to scan a patient, delay in patient transportation from the emergency department bay to the CT suite, and waiting while the patient was undergoing oral preparation for abdominal CT. The distribution of these contributing factors on each shift is shown in Table 2. Of the 11,616 min of total idle time, having no patients to scan accounted for 4479 min (38.5%). The differential contribution of this factor was 1841 min (41%) in period A, 805 min (18%) in period B, 492 min (11%) in period C, and 1341 min (30%) in period D. Patient transportation accounted for 11.7% of the total idle time. Of the 1359 min contributed by this factor, 141 (10%) occurred in period A, 381 (28%) were in period B, 631 (46%) in period C, and 206 (15%) in period D. Patient preparation with oral contrast material for abdominal CT was the only contributing factor to lack of use during 31% of the total idle time. The distribution of this factor per shift showed a contribution of 523 min (15%) in period A, 1034 min (29%) in period B, 1462 min (41%) in period C, and 536 min (15%) in period D.
|
|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
Management service companies that provide benchmarking for hospital nationwide use the total number of examinations per year as a measure of CT unit usage. For example, benchmark data on distribution of CT examinations per scanner per year is available for 69 hospitals in the state of Pennsylvania [3]. All hospitals performed more than 10,000 examinations per year, and the recorded usage of 150 CT units ranged from 5109 to 15,270 examinations per scanner, with an average of 8152 examinations. These data do not discriminate between scanners that operate 365 days a year for 24 hr a day, and those with limited or no activity during off-hours; therefore, the data do not allow estimation of the rate of CT usage on the basis of hours of scheduled activity.
On the other hand, some health care consulting organizations use a best practice—benchmark labor standard, rather than an equipment-throughput standard, to assess CT operations. An estimated value of 0.61 hr per examination is derived from paid technologist hours and worked hours per scan (Mackinnon B, personal communication). Using this standard, the theoretic maximal usage for an emergency department CT scanner that is staffed 8760 hr per year would be 14,361 examinations a year, or an average of 9.8 examinations per 6-hr shift. Our projected estimation from the study period is 11,570 examinations a year and an overall average of 7.9 examinations per 6-hr shift. We identified significant differential variance per shift with the lowest CT scanner usage from 7:00 A.M. to 1:00 P.M. (5.2 examinations) and highest usage from 7:00 P.M. to 1:00 A.M. (11.4 examinations).
Our study identified two principal reasons for lack of CT scanner usage. The first was that periods with no referrals often coincided with periods of low clinical activity in the emergency department. The second was a group of factors that can be classified mainly as operational inefficiencies that are more dependent on personnel and institutional resources.
Having no requests to scan patients accounted for 38.5% of idle time. Of the total time with no requisition, 41% (4472 min) occurred between 7:00 A.M. and 1:00 P.M., when the average number of patients scanned was only 3.45. This finding mirrors the pattern of patient visits to the emergency department, which are lowest (< 10% of total daily visits) during the early morning hours. Conversely, this is the busiest period for in-hospital CT examinations. In our institution, an average of 3500 examinations of outpatients per month and more than 1400 examinations of inpatients per month are performed on the three CT scanners that are not dedicated for emergency department use. According to our CT monthly performance data, outpatients have a 7-day wait for an appointment. This scheduling process permits a phantom patient to be scheduled for each fifth available time slot, to allow for emergent add-on outpatient requests. In addition, because of demands for CT, as many as 15% of the daily requested CT examinations for inpatients are delayed until the following day.
Identifying predictable periods of decreased use of the emergency department CT scanner allows opportunities to be considered for scanning nonemergent patients. For example, we found that the average use of the emergency department CT scanner during the 6-hr period from 7:00 A.M. to 1:00 P.M. was only 1.5 hr. Predictably short CT examinations of ambulatory patients (e.g., unenhanced brain and sinus studies) can be scheduled for the emergency department scanner during morning hours. Ways to avoid conflicting with emergency department operations and to ensure a seamless outpatient flow to and from the scanner must be addressed. Our CT scanner is bounded by the emergency department on one side and by an ambulatory radiology practice on the other, with independent access to the scanner. This physical distribution is well suited for scheduling and selective use of the emergency department CT scanner for outpatients from the ambulatory radiology service. Identification of the times of least operational activity also allows preventive maintenance to be more conveniently scheduled.
We found that patient preparation for abdominal CT accounted for almost one third of the time that the scanner was idle. However, because of the random distribution of the times of abdominal and pelvic examinations, patient preparation did not make a substantial differential contribution to scanning delays in specific shifts. The delays attributed to this factor were directly proportional to the number of patients scanned per shift. Depending on the clinical indication, individual patient preparation time is typically planned to range from 30 to 150 min. Our study did not assess the effect of this protocol on an individual patient's waiting time. "Preparation with oral contrast material" was entered into the data sheet whenever a patient was waiting to complete the indicated drinking time and no other factors were simultaneously contributing to the scanner's idle time. Thus, the actual patient preparation time is significantly longer than its calculated contribution to idle time. This nonquantified information may be relevant to improving efficiency in patient disposition from the emergency department and to improve the use of the scanner in busy periods when several patients may be waiting for abdominal examinations and no other CT requests are pending. Studies may be warranted to assess the role of unenhanced abdominal CT in screening for acute diseases in emergency department patients and to identify alternatives that would expedite the acquisition of diagnostic information.
In our setting, patient transport from the treatment areas is provided by emergency service assistants, who bring patients to the CT suite; CT technologists are responsible for returning patients to the emergency bay. The differential contribution of this factor to idle time is directly proportional to the intensity of clinical activity in the emergency department. In fact, the shift with the most transport delays (1:00 P.M.-7:00 P.M.) matches the shift with the largest daily volume of admissions. According to the emergency medicine department data registry, an average of 4800 visits are registered per month, and 50% of them are concentrated between noon and 8:00 P.M. The activity level in emergency departments is predictable and follows the time pattern of patient visits. Careful consideration of these patterns could help to achieve the appropriate distribution and use of resources. During busy hours, having emergency service assistants dedicated to radiology transport might improve operational efficiency.
Our data also emphasize the effect that proximity of CT services to the emergency department has on minimizing transport time, because the importance of this factor would predictably increase if the CT services were remote from the emergency center.
A limitation of this study is that data entry was susceptible to interregister variability. However, we minimized this variable by developing a consensus definition of the factors that contribute to idle time and by providing in-service instruction on the registry process before the study began. We also had staff radiologists closely monitoring the process as record keeping took place. A second limitation is that our data may be institution-specific and not necessarily applicable for benchmarking. Nonetheless, the data may be transferable to institutions with similar predictable patterns of patient visits to the emergency department. The information may also be useful for strategic planning when considering the physical integration of radiology services and emergency departments, acquisition of equipment, and allocation of personnel.
We recognize that achieving maximal CT usage may not be realistic and that inefficiencies can be introduced in an emergency department operation unless time is allowed for expansion and additional capacity. Notwithstanding, we found that emergency department CT scanners have predictable and consistent idle periods, and we conclude that changes can be implemented to enhance scanner usage based on identifiable patterns of emergency department activity. Efforts can be focused on facilitating examinations for outpatients by using the emergency department CT scanner and on reducing factors such as transport and lengthy preparation times that contribute to delays in patient throughput.
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
This article has been cited by other articles:
|
|
 |
|
  J. Gralla, F. Spycher, C. Pignolet, C. Ozdoba, P. Vock, and H. Hoppe Evaluation of a 16-MDCT Scanner in an Emergency Department: Initial Clinical Experience and Workflow Analysis Am. J. Roentgenol., July 1, 2005; 185(1): 232 - 238. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
