Outpatient Scheduling in the Outpatient Pediatric Center of GHZ: A simulation study to decrease the patient waiting time and pediatrician overtime

Eijken, Marcel van (2010) Outpatient Scheduling in the Outpatient Pediatric Center of GHZ: A simulation study to decrease the patient waiting time and pediatrician overtime.

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Abstract:Pediatricians of the GHZ (Groene Hart Ziekenhuis) experience long overtimes in their outpatient center, while outpatients experience long waiting times. To monitor their performance they set up a time registration system. This study uses the data gathered with this system to analyze the current performance of the outpatient center and to create a discrete event simulation model of a consultation session. We use this simulation model to test the impact of various changes in the current scheduling on the patient waiting time and the pediatrician overtime. Motivation and Objective Although waiting patients and physicians experiencing overtime are well-known phenomena in outpatient centers, the pediatricians of the GHZ believe that the current performance of their center can be improved on these aspects. To improve the patient waiting time and the pediatrician overtime we focus on the used scheduling methods, i.e. a set of rules that depict in what order and at what times patients are consulted. Our objective is to test various outpatient scheduling methods on their ability to decrease the patient waiting time and pediatrician overtime of the outpatient center. The Current Situation The outpatient center uses consultation sessions of 3 hours in which 12 patients can be scheduled in slots of 15 minutes each. The center differentiates between new patients and follow-up patients, i.e. follow-up patients are only consulted by a pediatrician, while new patients are first consulted by an intern and then by a pediatrician. Before consulting the new patient, the pediatrician discusses the new patient with the intern after which the pediatrician consults the new patient accompanied by the intern. These different consultations are scheduled in a specific order, the so-called 4-patient cycle: one consultation by an intern of a new patient is scheduled at the same time as three consultations of follow-up patients by a pediatrician. Consultations of new patients are therefore scheduled on specific appointment slots, follow-up patient on the other hand are scheduled arbitrary on one of the other slots. These outpatient scheduling methods result in an average pediatrician overtime of 24 minutes and an average patient waiting time of 20 minutes for an average of 10 patients per consultation session. Analysis on the flow of patients reveals that consultation durations approach the standard slot size of 15 minutes except for new patients which have average consultation durations of 18 minutes. Also standard deviation of consultations durations varies among patient groups. Another disturbing factor is the ‘waiting moment’ caused by the 4- patient cycle: either the pediatrician or the intern has to wait for the other to finish his or her consultation before they can both proceed with the new patient. Interventions We suggest five basic interventions on the current scheduling method to improve the pediatrician overtime and patient waiting time. (1) Bailey-Welch rule, i.e. scheduling of two patients on the initial slot. This creates a buffer of patients reducing the probability of the pediatrician staying idle. (2) Variable slot, i.e. increasing the slot size of new patients to 20 minutes. This creates a better match between the slot size and the consultation duration of new patients. (3) Flexible 4-patient cycle, shifting the appointment slot of the follow-up patients succeeding the new patient fifteen minutes forwards. This gives the pediatrician the opportunity to consult another patient instead of waiting for the intern to finish his or her consultation. (4) LVBEG rule (‘low variance beginning’ rule), i.e. the scheduling of patients with low variance on consultation duration at the beginning of the consultation session and patients with a high variance at the end of the consultation session. By grouping patients with low variance on consultation duration at the beginning of the consultation session, the probability of delayed consultations at the start of the consultation session is reduced. (5) Allocation rule, i.e. introducing a sequence in which appointment slots are filled: starting with the first slot and continue with the successive slots. The rule prevents a scheduling in which appointment slots in the middle of the consultation session are left open. Besides these basic interventions, we create another twelve interventions through combinations of the five basic interventions. Analysis of Interventions Since the various interventions change the currently used scheduling rules for consultation sessions, we build a simulation model of a consultation session to compare the impact of the interventions with the current scheduling. We use two scenarios to examine the performance of the various interventions. (1) Historical, i.e. 10 the representation of the current situation of the outpatient center. (2) Maximum utilization, i.e. a situation in which all appointment slots are filled. Instead of appointing one of the interventions as the ‘winner’, we use an efficient frontier to select a group of interventions that organize the consultation session most efficiently according to the patient waiting time and the pediatrician overtime. Three interventions are present on the efficient frontier of both scenarios (1) and (2): (A) the flexible 4-patient cycle, (B) a combination of the LVBEG rule and the flexible 4-patient cycle and (C) a combination of the LVBEG rule, the Bailey-Welch rule and the flexible 4-patient cycle. These interventions have the ability to reduce the patient waiting time up to 10 % or the pediatrician overtime up to 20 %. Conclusion The three best performing interventions have the flexible 4-patient cycle in common, an intervention that alters the strict sequence in which consultations have to take place. Therefore the most valuable conclusion is not that performance can be increased but that the pediatric department has to loosen the strict sequence in which consultations have to take place.
Item Type:Essay (Master)
Clients:
Groene Hart Ziekenhuis
Faculty:BMS: Behavioural, Management and Social Sciences
Subject:85 business administration, organizational science
Programme:Industrial Engineering and Management MSc (60029)
Link to this item:http://purl.utwente.nl/essays/60790
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