Introduction Mid-level providers (MLPs) are used in many emergency departments (EDs) to provide care in a low-acuity, high-volume setting, and are able to see more patients and generate more relative value units (RVUs) than residents in this setting. It is unknown if MLPs are as productive as emergency medicine residents in a high-acuity setting.
Objective To determine if there are productivity differences between residents and MLPs, as defined by patients seen (pt/h) and RVUs generated per hour (RVU/h), in a high-acuity area of the ED.
Methods This is a retrospective review of emergency medicine residents and MLPs assigned to a high-acuity area of a single 45 000 volume community ED. Number of patients seen and RVUs generated were recorded, and pt/h, RVU/h and RVU/pt were calculated. Two-tailed t test was used to compare resident and MLP performance.
Results 55 MLP and 98 emergency medicine residency shifts were included for comparison. During the study period, MLPs saw 1.56 pt/h (CI±0.14), while residents saw 1.23 pt/h (CI±0.06, p<0.0001). MLPs generated 3.19 RVU/h (CI±0.29), while residents generated 3.33 RVU/h (CI±0.17, p=0.43). Residents generated 2.73 RVU/pt (CI±0.09), while MLPs generated 2.05 RVU/pt (CI±0.09, p<0.0001). In comparing the subgroup of postgraduate year 3 residents (PGY3s) with MLPs, MLPs still saw significantly more patients (1.30 vs 1.56, p=0.003), but PGY3s generated 3.58 RVU/h compared with 3.19 RVU/h for MLPs (p=0.06). PGY3s generated 2.79 RVU/pt compared with 2.05 for MLPs (p<0.0001).
Conclusions In a high-acuity area of the ED, MLPs see more patients per hour than residents, but generate fewer RVUs per patient. This suggests that residents may document more thoroughly than MLPs. Alternatively, MLPs may elect to see less sick patients even when working in a high-acuity area.
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Emergency department (ED) overcrowding and waiting times are of growing concern as the number of visits continues to rise. The National Hospital Ambulatory Medical Care Survey estimates that ED visits in the USA have grown from 94.9 million in 1997 to 123.8 million in 2008.1 ,2 In an effort to improve patient safety and satisfaction, many EDs have turned to mid-level providers (MLPs), a term that includes both advanced nurse practitioners and physician assistants, to augment the emergency physician workforce. The percentage of EDs reporting use of MLPs has increased from 28.3 in 1997 to 77.2 in 2006, and is probably even higher among academic EDs.3 ,4 The percentage of patients presenting to the ED who are evaluated by MLPs has also increased sharply, from 4.1 in 1995 to 14.5 in 2009.5
Utilising MLPs has allowed EDs to better manage increasing patient volumes and helps to offset the need for more emergency physicians.4 ,6 MLPs typically care for a low-acuity case mix; however, current guidelines do not address the function of the MLP in the care of high-acuity patients.7 As a result, MLPs may serve in a variety of roles depending on state law and hospital policy.4 Although MLPs are most commonly tasked with the care of patients triaged as low-acuity rather than high-acuity, there is little evidence to support this practice. This study compares, using three measures, the productivity of MLPs and emergency medicine residents of different training levels staffing a high-acuity area: the number of patients seen per hour (pt/h), the number of relative value units (RVUs) generated per hour (RVU/h), and the number of RVUs generated per patient (RVU/pt). The RVU is a measure used by third-party payers in the USA to determine physician compensation in a fee-for-service model. This measure attempts to incorporate three variables of patient care: physician work, practice expense and cost of malpractice insurance. We chose this as a marker of productivity because, unlike pt/h, this measure incorporates the complexity of individual patient complaints, procedures performed, and ultimately the billable work performed by an individual.
This is a retrospective chart review of emergency medicine resident and MLP productivity in a high-acuity area of a single-community ED. The study was reviewed and approved by the hospital's institutional review board.
Setting and study subjects
The study was performed at a single-centre 45 000 volume community ED from July 2009 to September 2010. The ED has a low-acuity area staffed with single coverage by six MLPs (five physician assistants and one nurse practitioner), and about 20% of the ED census is seen in this area. In addition, the same group of MLPs work two high-acuity day shifts each week, on Monday and Thursday. Monday has MLP high-acuity staffing to account for the higher census that occurs on Mondays. This community ED also hosts emergency medicine residents on an irregular basis, as it is a community affiliate of a residency training programme, and MLPs staff the high-acuity area on Thursdays because it is a resident conference day. The MLPs have all been in practice in the study ED for at least 2 years and are well versed in the electronic medical record and operations of the department.
The emergency medicine residency training programme is a 4-year programme, and all four classes rotate through the community site. Residents are eligible to work any shift at the community site except for Thursday day shifts, as this is their mandatory education time. The computer tracking system and electronic medical record at the community site are identical with the systems used at the main teaching hospital.
Because MLPs do not work evenings or nights in the high-acuity area, only day shifts on Mondays and Thursdays were used (08:00–18:00) for MLP shift data, while day shifts for emergency medicine residents (07:00–17:00 or 08:00–18:00) included all days throughout the week. Patients with Emergency Severity Index (ESI) scores of 1, 2 and 3 are seen in the high-acuity area of the ED. MLP shifts in low-acuity areas were excluded. Off-service resident rotators and attending physicians were also excluded.
Data collection and processing
All research associates were trained by a single researcher, and data were entered into a standardised Excel spreadsheet. The research associates collected census and productivity data through query of the Verinet coding system (LightSpeed Technology Group, copyright 2004–2005). The Verinet system records individual provider shift data regarding the total number of patients seen, the total number of RVUs generated, and the mean RVUs generated per patient (RVU/pt). In the event of patients being signed over from shift to shift, the transfer of care to the next provider is recorded on the electronic medical record, but the system credits the original provider with care of the patient. Shift hours were recorded from the resident and MLP work schedules and cross-referenced with the Verinet system on a day-by-day basis to ensure accuracy of the schedule. RVUs per hour (RVU/h) and patients seen per hour (pt/h) were calculated using the data from the Verinet system and the monthly schedule. Census data were also recorded to ensure that there were no differences in overall daily ED census.
A power calculation determined that at least 21 shifts per group were required to determine an absolute difference of 0.25 pt/h between MLPs and emergency medicine residents working high-acuity shifts with an α of 0.05. This calculation used prior data on the same MLPs’ productivity extrapolated from low-acuity shifts at another site.8 Data were analysed using the two-tailed t test to compare pt/h, RVU/h, RVU/pt and daily census between the two groups. Comparison was made between MLPs and all residents, as well as subgroups of residents with different levels of training. Simple linear correlation was used to determine the correlation of pt/h with RVU/h.
Fifty-five MLP and 98 emergency medicine resident shifts were included in this study. Resident shifts were distributed among resident level of training as follows: 29 shifts by residents in their first year of postgraduate training (PGY1s), 27 shifts by residents in their second year of training (PGY2s), 21 residents in their third year of training (PGY3s), and 21 shifts by residents in their fourth year of training (PGY4s). All shifts were 10 h in length (either 07:00–17:00 or 08:00 to 18:00).The mean daily ED census was 130 on days when MLPs worked high-acuity shifts as well as when residents worked high-acuity shifts (p=NS).
Evaluation and management codes (E/M codes) are part of medical billing processes in the United States that are required for reimbursement for any patient encounter. Lower numbers indicate less complexity or acuity for the patient encounter, and higher numbers indicate higher complexity and acuity. During the study period, 0.16% of the total patients seen at the institution were coded out to 99281 (E/M level 1), 0.30% were coded out to 99282 (E/M level 2), 49.5% were coded out to 99283 (E/M level 3), 29.9% were coded out to 99284 (E/M level 4), 17.9% were coded out to 99285 (E/M level 5), and 2.27% were coded out to 99291 (E/M critical care). In terms of RVUs, this translates to 0.03% of RVUs generated from E/M level 1 charts, 0.12% of RVUs generated from E/M level 2 charts, 30.3% of RVUs generated from E/M level 3 charts, 34.3% of RVUs generated from E/M level 4 charts, 30.4% of RVUs generated from E/M level 5 charts, and 4.90% of RVUs generated from E/M critical care charts. Therefore, taking all-comers (both low-acuity and high-acuity areas of the ED), the mean RVU/pt for the study institution was 2.79 during the study period.
During the study shifts, there was a strong correlation between pt/h and RVU/h for emergency medicine residents as well as MLPs, with r=0.81 and 0.86, respectively.
During the study period, PGY1s working in the high-acuity area treated a mean of 1.11 pt/h (CI±0.094), PGY2s treated a mean of 1.25 pt/h (CI±0.15), PGY3s treated a mean of 1.33 pt/h (CI±0.14), and PGY4s treated a mean of 1.27 pt/h (CI±0.12). MLPs saw more patients than any residency class, with a mean of 1.56 pt/h (CI±0.14, p<0.02 for all classes, figure 1).
PGY1s generated a mean of 3.03 RVU/h (CI±0.32), PGY2s generated a mean of 3.27 RVU/h (CI±0.37), PGY3s generated a mean of 3.58 RVU/h (CI±0.32), and PGY4s generated a mean of 3.56 RVU/h (CI±0.38). MLPs performed similarly to residents, with a mean of 3.19 RVU/h (CI±0.29, p value range 0.07–0.75, figure 2).
PGY1s generated 2.71 RVU/pt (CI±0.13), PGY2s generated 2.65 RVU/pt (CI±0.19), PGY3s generated 2.75 RVU/pt (CI±0.21), and PGY4s generated 2.82 RVU/pt (CI±0.19). MLPs generated fewer RVU/pt than any resident class, with a mean of 2.05/pt (CI±0.09, p<0.0001, figure 3).
MLPs outpace emergency medicine residents in terms of the number of patients they see per hour in a high-acuity area. This may be related to several factors. Owing to reimbursement requirements and hospital policy, emergency medicine residents must work under the direct supervision of an attending physician. Residents must present each patient to an attending physician, after which a discussion involving patient management typically occurs. These discussions may be lengthy depending on the particular resident's fund of knowledge and the attending physician's comfort with the resident's skills. Often, additional discussions regarding the patient's response to treatment occur before the patient's final disposition. Residents may also receive intermittent didactics on pertinent educational topics as they arise throughout the course of the shift. Other studies have demonstrated that emergency medicine residents spend significant amounts of time interacting with attending staff, and these interactions are lengthier for the less-experienced residents.9 ,10 All these discussions take time and may be partly responsible for residents being able to see fewer patients than MLPs during shifts of the same duration.
Residents may also see fewer patients because of time spent looking for the attending physician to guide them in the care of the patient. Similarly to many institutions, attending physicians at the study institution are caring for their own patients while supervising residents. Therefore, the attending physician may be indisposed with other patients, which may delay initiation of necessary testing as well as final disposition decisions.
A prior study has shown that MLPs are more productive than residents in a low-acuity area as measured by both RVU/h and pt/h.11 In that study, MLPs practised independently, and this was cited as a reason why they were more productive than residents working in the same environment. Although MLPs in our institution are fully licensed practitioners who may practise independently, they do have attending physician back-up if requested. MLPs typically initiate work-ups on their own and provide attending physicians with a brief synopsis if they plan to disposition a given patient to an inpatient setting. Therefore, attending physicians are involved in a supervisory capacity for many patients seen by MLPs. Although it is difficult to quantify, it is likely that these interactions are briefer than those between residents and attending physicians. MLPs probably receive less bedside teaching than residents. These factors may make them more efficient in seeing higher numbers of patients than residents.
Despite seeing more patients than residents, MLPs generated fewer RVUs per patient seen, resulting in similar RVU/h among residents and MLPs. Indeed, MLPs working in the high-acuity area generated lower RVU/pt than the departmental mean for all-comers, even though they were working in the high-acuity area. The reasons for this are unclear. It may be that MLPs choose to see less-acute patients. Since MLPs work the majority of their shifts in the low-acuity area of the ED, they may feel more comfortable seeing patients who are less sick. Although the MLPs were assigned to work in the high-acuity area where patients are triaged as ESI-1, ESI-2 and ESI-3, they may have opted to see the lower-acuity patients available within the area, leaving the higher-acuity patients for the attending physician to manage on his or her own.
Another explanation for the lower RVU/pt generated by MLPs is that emergency medicine residents may document more thoroughly than MLPs. Third-party payers require a more detailed level of documentation in order to bill a higher level of care. For example, for a patient who presents for suture removal and bills at the lowest possible rate (E/M code 99281), a review of systems is not required to be documented, and only a problem-specific physical examination is necessary. In order to bill for a critically ill patient (E/M code 99285), the physician or MLP must include a full physical examination covering eight or more organ systems, as well as a full review of systems covering at least 10 systems. Failure to document appropriately will preclude the hospital from billing at the higher rate even if the patient's complaint results in a critical diagnosis. Residents work closely with attending physicians, who are incentivised to capture the maximum number of RVUs available on a given presentation, whereas MLPs are not. Owing to the lower-acuity environment in which MLPs are accustomed to working, there is less necessity to document to the extent that would be necessary to achieve higher billing codes. MLPs working in the high-acuity area only generated 2.05 RVU/pt, a number that would be equivalent to an E/M level 3 visit (1.80 RVUs), and significantly lower than expected.12 Although MLPs are reimbursed at a lower rate than patients seen by physicians in the ED, the RVU data included in this study represent the billed rate and therefore would not explain this difference.
MLPs have very little specialty-specific training in the ED, particularly regarding billing. Specialised ED training for MLPs, such as a fellowship in emergency medicine, has been shown to be a predictor of improved RVU generation.13 Alternately, studies examining the effectiveness of education directed specifically at increasing RVU generation have been successful when applied to emergency medicine residents in an academic setting, although this has not been studied in MLPs.14 ,15
Our study was performed in a single-centre community ED. The productivity of the MLPs and emergency medicine residents at this institution may not extrapolate to other EDs. The number of MLPs (n=6) evaluated in this study had variable lengths of work experience and may not reflect the national population of ED MLPs. The emergency medicine residents evaluated in this study were performing an off-service rotation among attending physicians who will typically see the majority of their patients independently. It is difficult to know the degree to which attending–resident interactions affected data. Since attending coverage is scheduled to manage the ED volume regardless of resident schedules, emergency medicine residents and MLPs may cherry-pick or otherwise choose patients in a non-chronological order. In this study, there was no mechanism in place to compare the acuity of patients seen between MLPs and emergency medicine residents. Although daily ED census data for emergency medicine resident and MLP shifts were the same, there is no way to know if minute-to-minute or hour-to-hour fluctuations in volume were different between the days worked by each group. In addition, there is no way to control for factors such as hospital crowding that may have differed on the days covered by MLPs as opposed to emergency medicine residents.
As EDs continue to pursue innovative means to address increased volumes of patients and crowding, MLPs represent an attractive tool for increasing productivity and throughput. MLPs in high-acuity areas may be more productive than emergency medicine residents in terms of the volume of patients they see, but do not generate as many RVUs per patient. It is uncertain whether this is related to patient selection or documentation deficiencies. Further study is needed to evaluate whether documentation training would improve the utility of MLPs in a high-acuity setting.
Contributors DJ, RJ, KH and DG conceived the study. DG, DJ and RJ performed data collection. RJ performed statistical analysis. DJ, RJ and KH interpreted data. All authors were involved in drafting the manuscript.
Competing interests None.
Ethics approval St Luke's Bethlehem Institutional Review Board.
Provenance and peer review Not commissioned; externally peer reviewed.
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