Patient severity matters for night-shift workload for internal medicine residents in Taiwan

Shift work, which improves inpatient care during after-hours and on weekends, is an essential component of current inpatient care models [1]. The main workload during on-call shifts includes caring for previously admitted patients and managing new admissions, if any [2]. However, criticism of shift work has been ongoing for decades, mostly as a result of the sleep deprivation and the impaired neuropsychological performance of the workers, which raised concerns about patient safety [3].

The Accreditation Council for Graduate Medical Education (ACGME) in the United States mandated limits on resident work hours in 2003, including a 30-hour limit on continuous shifts [4]. Most controversy focused only on the positive and negative effects of work hour restrictions [5],[6], until the conceptual framework of work intensity was emphasized again recently by Horner and coworkers [7]. In Horner’s framework, patient factors, provider factors and practice-based factors were three essential confounders for clinical work demand, which in turn contributed to physician work intensity and influenced physician health and patient outcomes. Work hours, which could be classified as practice factors in the Horner’s model, is one of the contributing factors of workload which has been investigated quite often. However, provider factors and patient factors were relatively neglected in the current literature.

To improve residents’ health, it is reasonable to reduce the night workload as much as possible, unless this could compromise patient safety or quality of care [8]. Libby and coworkers investigated the importance rating of beeper calls to interns, and revealed that nearly 60% of the calls were not relevant to patient care and 37% interrupted teaching or patient-physician interactions [9]. Some researchers also revealed that nurses and doctors exhibited different patterns of paging [10]. Some authors therefore advocated that unnecessary calls at night should be reduced. In addition, paging frequently interrupted work and rest at night [11]. However, few studies have attempted to predict night workload and to devise ways to achieve reasonable on-call workloads. The reasons of calling on-duty residents have been extensively studied in several different settings, but the sources of calls which could be helpful in predicting workload were rarely mentioned. Calls from stable, critically ill patients, or patients in other special conditions, may led to different pattern of care.

In order to contribute to the groundwork of establishing reasonable on-call workload, our research aims to study the night-shift workload for residents and focuses on not only the reasons of placing calls at night, but also the patient sources of calls and workload produced after the calls. Although workload is usually measured by census of patient encounter, we hypothesized that resident workload is associated with patient severity. By comparing the reasons of calls and workload produced after calls, our hypothesis that different patient produced different resident workload could be tested.

We believe that our study is the first report about the relationship between patient factors and resident workload. In the conceptual model proposed by Horner, patient factors, provider factors and practice factors contributed to the clinical work demands and work intensity, which in turn influences patient outcomes [7]. Most previous studies addressed the practice factors, such as duty hour design and protected sleep time for residents [15]. However, clinical severity of patient, which is an important patient factor in Horner’s framework, has been scarcely taken into consideration on workload studies.

In the pager era, several ground work studies have already been conducted. Previous studies have revealed the fact that half of pager calls were not relevant to patient care, and most of them did not affect immediate patient management [9],[10]. Beebe also conducted important work that investigated the reasons for beeper calls and rated their urgency. Two important findings were that the most common reason for calls (29%) was a change in the patient’s status, and that ratings of urgency made by nurses were not good predictors of the physicians’ responses to the call [14]. However, both studies included complex patient populations, including ward and ICU patients in the former, and pediatric, medical, surgical, and orthopedic patients in the latter. The work done by Katz et al. revealed that nurses and doctors exhibited different patterns of paging medical interns and highlighted unnecessary pages [10]. The study included only medical patients, however it had the limitations of covering relatively short time periods and performing in 1980s. Besides, none of the previous studies attempted to identify and compare the reasons for the calls among different patient groups.

We investigated the sources and reasons of the after-hours calls, their patterns, and the on-call workload in an acute-care general medicine population, and we used a sufficiently long study period. The most valuable finding in our study is that the reasons of night-shift calls were significantly different in patients from different clinical status categories. The workload produced after calls and the behavior pattern of the on-duty residents were also different. In the future, we may predict on-call workload by analyzing the clinical severity status of responsible patients.

Consistent with previous studies that examined night calls, the assessment of patients with complaints or changes in vital signs was the most common reason for the calls in Harvey’s [11] and Wong’s reports [16]. The former used numeric pagers while the latter used alphanumeric pagers that could display both numbers and text. In our study, abnormal vital signs were the leading reason of call in stable, unstable and DNR patients, although the proportion of call reasons was different. These results have important implications for the response to clinical events. There is an inevitable time lag between finding an abnormal patient condition and reaching the on-call physician. Calling via mobile phones may shorten the time lag compared to traditional paging systems, but has been criticized by residents as being highly disruptive for the patient care activity [17]. It calls for more study to prove the advantage of using mobile phones in clinical settings. Besides, most previous studies revealed a low percentage of bedside visits, from 10.3% to 28%, by on-call physicians [11],[13]. In our study, immediate (within 15 minutes) bedside visits occurred in 27.8%, and delayed visits in 14.5% of the calls. The higher rate of bedside visits was probably due to a higher proportion of abnormal vital signs in the study population, a different communication style using mobile phones, or a changed doctor-patient relationship and culture that exist nowadays. All patients in this study suffered from acute illness and were admitted from ED, and the picture was typical for an acute general medicine unit. Our study had no historical control and, thus, it could not make further deductions.

Table 4 summarizes the key studies from the related literature that examined pages and calls placed to physicians. In previous studies, the observation periods ranged from 1 week to 18 months. Our study involves the longest study period in the literature to date. A two-year long study period allowed us to minimize the observation effect on the study participants (night shift nurses) and depicted the real practice pattern at night. A recent trial with a comparably long study period investigated the workload of on-call medical interns for 2 years, but paging was not taken into consideration [6]. Our study provided supplemental information to the researchers.

Our study may have several meaningful clinical implications. First, the 457 DNR patients, who within the study period in our hospitalist setting were a minority (18.1%) of our patient population, surprisingly, accounted for one third of the night calls and nearly one half of the immediate bedside visits made by on-call residents. DNR patients had different reasons for placing the calls as compared to general patients, but had similar reasons as compared to the unstable patients. This finding should be emphasized, because we tend to ignore the workload of palliative care, or so-called conservative care, which is provided to DNR patients. DNR orders for old, co-morbid patients are not uncommon in Taiwan, especially when these patients face acute illness. Our study showed that the workload involved in palliative care was much heavier than expected.

Second, the workload that is required for unstable patients was distributed evenly throughout the whole night. Similar results were found in Beebe’s work, where the number of emergency calls was comparable regardless of whether they occurred during the day or the night [14]. In contrast to the stable and DNR patients, the conditions affecting unstable patients happened at any time, and often could not be managed on a “batch” basis. To improve the sleep fragmentation of the on-call residents, it was suggested that non-emergent calls be delivered by text messages on a batch basis [18]. However, the pattern of unstable patient calls, as shown in this study, may disturb the sleep of the on-call residents all night long. Therefore, the protected sleep time is probably the best strategy to deal with this situation [15].

Early in the 1990s, Harvey pointed out that studying the night calls allowed specific strategies to reduce the number of calls to be identified [11]. However, no known interventions have been proposed to effectively reduce night calls in the following decades. The lack of front-line information may explain the knowledge gap in dealing with the night shift workload. That’s why we have attempted to perform the ground work on this issue to help provide some initial findings.

With regards to the methodology of the night call study, earlier studies tended to record data first-hand from nurses or doctors [10],[11],[14], while recent studies usually adopted the web system records [16],[18],[19]. The web system records can reduce the number of instances when data are missing, but might underestimate the events required to call if the responsible resident was already on the ward [19]. In our study, the night shift nurses were ordered to record every event in which they needed to call the physicians and they were, therefore, the ones to report the data first-hand. In addition, the web system records cannot help identify whether a call was placed by nurses or by doctors if it originated from the nurses’ station [11]. Therefore, the recording, as performed by nurses, provides valuable and correct information. A previous study demonstrated that nurses completed 95% of the records, while interns completed 86% of them [11]. The on-call residents may often be interrupted or they try to sleep at night, which may explain why they recorded the calls to a lesser extent than nurses. From this point of view, the nurses’ first-hand records appeared to be the most reliable ones. Further studies may combine nurses’ records with web registration data to make the design more accurate. In addition, it also worth recording the detailed managements done by residents after the calls. How patient care is organized and what resources are needed are essential for patient safety at night shifts.

Our study had several limitations that are worth noting. First, the reasons why patients called the night shift nurses were not studied. In a previous study, the reasons that made patients call nurses were different from the reasons that made nurses call doctors [20]. Our study, however, focused only on the need to call residents whose response and workload could therefore be studied. On-call residents may consult attending hospitalists, but this was not included on the record forms, either. Second, we only surveyed the needs for resident care at night, an aspect that could not be generalized to the day and evening shift. The care at night aims to provide the best possible sleeping environment for the patients [21]. The night call studies can reveal the patients’ real needs during the night, without being confounded by daytime activities. While most other studies were conducted at daytime, it is mandatory to gather the front-line information at night to improve nighttime problems [22]. Third, in our hospitalist service, we rarely have new admissions during night shifts. Therefore, the reasons for the calls were excluding the ones that were placed for new admissions. In other hospitalist programs, where night shift admissions are common, our data regarding the night workload may be underestimated. However, the calls for new admissions, if pooled into the statistical analysis, will inevitably distort the needs of inpatients during the night hours. Our study focused on inpatients’ calls at night, rather than on calls for managing admission process. Therefore, the previously admitted patients and new admitted patients should be considered separately. Forth, time spent on patient care should be an important endpoint in assessing physician workload, but we could not address it based on our data. Time spent on managing the patient’s call is highly related to the resident’s training and personality, which have been classified into “provider factors” in Horner’s framework and warranted further research. Fifth, the study was conducted in single academic medical center in Taiwan. The generalizability of our results to other settings has not been proved.

The clinical state of the patients determines the workload during the night shift in a general medicine service. Both the cause and effect of the night calls differ among patients in different clinical states. Vital sign changes that needed assessment were the leading reasons for calls that were placed at night, and this was particularly the case for unstable and DNR patients. In the general medicine unit, DNR patients contributed substantially to the workload at night, to an extent comparable to unstable patients. Researcher should be reminded that beyond work hour, patient factors determine on-call workload. In different residency programs, factors other than work hour mandate investigation to allow fair comparisons. Further studies to predict the workload based on patient composition are warranted.