UCC_ProjectGoalsHighLevelCM.pdf

8/9/2019 UCC_ProjectGoalsHighLevelCM.pdf

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Urgent Care Center

Problem Description

Problem Statement

The administration of the SM Municipal Hospital is anxious to evaluate the possible benefit of some

procedural changes relating to the operation of its Urgent Care Clinic (UCC) that that is associated with

the Emergency Department but operates (more or less) independently from it. To a large extent thesechanges have their origins in the need to meet new turn-round standards for patients that are being

discussed at the provincial level. A decision was recently made to undertake a simulation study to gain

some insight into the impact of these policy changes upon the flow of patients through the UCC.

The issue to be explored in the study is a means for resolving the frequent complaints about excessivewaiting time for a second consultation with a doctor following the completion of diagnostic tests.

SUI Details

Care Center Resources

Information System: The hospital has embraced information technology and, in particular, uses an

information system (IS) that supports the progress of patients through the various stages of care both in

the Emergency Department and in the UCC. The IS includes real-time patient tracking, clinical chartingand clinician order entry, charge capture, and comprehensive reporting capabilities. Patient tracking

assists UCC staff in allocating patients who are

(a) waiting for an interview with the triage nurse,(b) waiting for a first consultation with an UCC doctor,

(c) waiting for diagnostic tests,

(d) waiting for test results to be returned to the examining doctor.

Personnel: The medical personnel of the UCC consists of a triage nurse and two doctors dedicated to

the treatment of UCC patients. Periodically special emergency circumstances can occur during which

the doctors from the UCC are temporarily reassigned to assist in the Emergency Department.


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UCC Center Layout: The center consists of:

A triage station to receive arriving patients

Four treatment rooms where doctors see patients

A waiting area for patients waiting to see one of the UCC staff.The following diagram shows the layout of the Center.

Patient Care

UCC Patients: The UCC provides a medical care facility for patients who are suffering from ailments

that are not life-threatening (e.g., abdominal pain, eye infection, lacerations, breathing issues, etc). They

are sub-divided into two categories following a screening by the triage nurse, as outlined below.

Emergency Patients: High-risk patients arriving at the hospital (typically those arriving by ambulanceand requiring immediate care) are treated in the Emergency Department. With this organizational

structure, the medical staff of the Emergency Department is immediately available to provide emergencycare for arriving patients who are in life-threatening circumstances.

Triage The first stage in the treatment of drive-in patients is an assessment by the triage nurse consisting of

o An interview during which the patients ailment is evaluated.o Basic medical data such as blood pressure and temperature are acquired together with key

facets of medical history; e.g., medications being taken. On the basis of the information acquired, the triage nurse assigns one of two priority designation to

the patient:o NIA : needs immediate attentiono CW: can wait

The assigned designation has an impact on the immediacy with which subsequent treatment isallocated.

Treatment

Room 1

Treatment

Room 2

Treatment

Room 3

Treatment

Room 4

Triage Station

Waiting

Area

Doors used by

arriving patients

Door to otherhospital

departments

Washroom


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Treatment of CW (Can Wait) Patients Priority:

o A CW-patient sees a doctor only when there are no NIA-patients waiting for a firsttreatment;

o CW patients are treated before any NIA patients that are waiting for a second treatmentby a doctor (see the next section).

o CW-patients are treated on a first-come first-serve basis; Following their consultation with a doctor, CW patients leave the hospital with suitable

recommendations, and possibly a prescription, provided by the doctor.

Treatment of NIA (Need Immediate Attention) Patients

Priority when waiting for first treatmento NIA patients waiting for their first treatment with a doctor have the highest priority and

see a doctor before any CW patient

o NIA patients are treated on a first-come first-serve basis If after the first treatment, no further treatment is required, the patient leaves the hospital with

suitable recommendations, and possibly a prescription, provided by the doctor. If after the first treatment, the outcome of their first treatment by the doctor results in the need for

one or more diagnostic tests to be carried out, the patient is directed to the appropriate area where

the prescribed tests are carried out (e.g., blood and/or urine tests, x-rays, CT scans etc.). Following the completion of these tests the patients return to a waiting area where they await the

processing of the tests. Patients wait for a second consultation with a doctor once the test results become available (via

the EDIS).

Priority when waiting for second treatmento This second consultation takes place only when there are no patients of either category

(CW or NIA) waiting to see a doctor for a first treatment. After the second treatement, as an outcome of the discussion of the test results, the patient either

leaves the hospital or is admitted for continuing treatment. In either case the patients

involvement with the Emergency Department ends.


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Project GoalAs outlined earlier (section 1.2.3) patients waiting for a second consultation with a doctor to review the

diagnostic test results must wait until there are no patients waiting for a first consultation with a doctor.

Circumstances often arise where this policy results in an unreasonable delay for patients awaiting asecond consultation. To rectify this situation, a proposal has been made whereby a consultation of a CW

patient with a doctor is interrupted by a patient waiting for a second consultation if the wait time of that

patient has exceeded 30 minutes. A goal of the simulation study is to obtain some insight into the impactof this policy change.

Parameters

niaPriority2ndTreatmentPolicy: Determines which policy to apply to NIA-patients waiting for their2

ndtreatment after results from diagnostic testing is available. This parameter can assume one of two

values:

oNOTIMING: Indicates the default priority policy where the second treatment for NIA-patientstakes place only when there are no patients of either category (CW or NIA) waiting to see adoctor for a first treatment.

o WITHTIMING: Indicates the alternate priority policy where the treatment of a CW patient will be

interrupted by an NIA patient waiting for a second consultation if the wait time of that NIApatient has exceeded 30 minutes.

Experimentation

Study: Steady state study.

Observation Interval:

Time units areminutes

Cannot be predetermined because a steady state study is requiredBase Case: Case where niaPriority2ndTreatmentPolicy=NOTIMING.

Alternate Case: Case where niaPriority2ndTreatmentPolicy= WITHTIMING.

Output

The following output data has been identified as having particular relevance to achievement of the

project goal as outlined in section 2.1.

The following output is used to measure the achievement of the project goal:a) avgNIANumWaiting2nd: The average number of NIA patients waiting to see a doctor for a

second consultation to discuss the results of diagnostic tests,b) avgNIAWaitingTime2nd: The average time spent waiting by NIA patients waiting to see a

doctor for a second consultation to discuss the results of diagnostic tests.

The following output is used to measure waiting times, queue lengths and utilization of resources tohelp explain the results of the simulation experiments:

a) avgNumTriage, avgWaitingTimeTriage: The average number of patients waiting to see thetriage nurse and the average time spent waiting.

b) avgCWNumWaiting, avgCWWaitingTime: The average number of CW patients waiting to see adoctor and the average time spent waiting

c) avgNIANumWaiting1rst, avgNIAWaitingTime1rst:The average number of NIA patients waitingto see a doctor for a first consultation and the average time spent waiting.

d) triageNurseUtil: The percentage of time the triage nurse is busy.e) doctorsUtil: The percentage of time the doctors are busy (this can be determined by

determining the average number of patients being seen by a doctor and dividing by 2).


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ABCmod Conceptual Model

High Level Conceptual Model

Simplifications

a) As Noted in the SUI Details, both doctors are sometimes required to assist in the hospitals

emergency department when special circumstances arise. Because the occurrence of such specialcircumstances is infrequent, this behaviour will not be incorporated in the model.

b) Following their first consultation with the doctor each NIA patient may be required to undergo one ormore diagnostic tests. The number of such tests assigned to each patient and the duration of eachtest (which would necessarily include time spent waiting for access to the testing facility) arerandom variables. This facet of the UCCs operation will be simplified by assuming a single randomvariable that will represent the time taken for diagnostic tests by any particular patient. In otherwords this random variable will consolidate the number of tests and their individual durations.

c) The doctors are not explicitly modeled and are represented as a resource group with a size of 2 (i.e.only two patients can be treated at the same time and hence only 2 patient entities can be memberof this resource group).

d) To model the priority in which patients are seen by doctors, two queues are used. A priority queueis used to model the priority of CW patients and NIA patients waiting to see a doctor for the firsttime. A separate FIFO queue is used to represent the order in which NIA patients waiting to see adoctor for the 2ndtime (the priority of these patients relative to the patients in the priority queue

depend on the value of the parameter niaPriority2ndTreatmentPolicy)

Structural Vi ew

Figure 1 Emergency Room Structural Diagram

Entity Categories

1. Patient: A consumer entity category representing the patients that requires the services in theemergency room. This entity category has ascope= Class. Patient entities have the attributeTypeset to eitherNIA(needs immediate attention) or CW(can wait).

2. Nurse: represents the triage nurse receiving and classifying patients, one at a time.3. Doctors: A resource group entity used to represent the two doctors that are available to treat

patients.

4. JustArrived: represents the queue of patients waiting for the triage nurse.

Q.JustArrivedR.Nurse

RG.Doctors

Q.Triaged

Q.ReceivedTests

iC.Patient


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5. Triaged: represents the queue of patients waiting to see a doctor for the first time. The queuingdiscipline used places CWpatients at the end of the queue, andNIApatients before the first CW

patient in the queue.6. ReceivedTests: represents the queue ofNIApatients waiting to see a doctor for a second time

after tests results have been received.

Notes:

The Patient entitys attribute TimeEnteredQueueallows the possibility of selecting patients fromQ.ReceivedTests before CWentities at the head of Q.JustArrived during the alternative case and

to interrupt FirstTreatment activities involving CW patients.

Note that a single queue with a priority discipline will be used for dealing with arriving patientsrather than two separate queues. This will require two attributes for Q.Triaged; namely,numNIA, numCW, to keep track of the number of NIA patients and number of CW patients

respectively in the queue.

Behavioural View

NOTES:

- Both CW-Patients and NIA-Patients start with the same life cyle, that is, they are involved in theArrivals action, the Triage activity, and a FirstTreatment activity. Subsequent progression of the

life-cycle differs for the CW-Patient and NIA Patient.

- FirstTreatment activity instances involving CW Patients may be interrupted while thoseinvolving NIA patients cannot. The interruptions only occur during the alternate case ofexperimentation, that is, when niaPriority2ndTreatmentPolicy= WITHTIMING.

- CW Patients always exit the model after the FirstTreatment activity instance in which theybecome involved has terminated.

NIAP

atients

Arrivals

Triage

FirstTreatment

LabTests

SecondTreatment

CW Patients

Patient Life Cycle

FirstTreatment

SecondTreatment

CW Patients

Doctor Life Cycle


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- NIA patients after the FirstTreatment activity may exit the model or become involved in aLabTests activity instance which implies they become involved in a SecondTreatment activityinstance before leaving the model.

Input

Exogenous Input (Entity Stream)

VariableName

Description Domain Sequence Range Sequence

uPatient(t) This inputentity stream

represents the

arriving

patients.

RVP.DuPatient() N/A; 1 patient arrives at each arrivaltime.

Endogenous Input (Semi-Independent)

Variable Name Description Value(s)

uTirageTime duration of visit with triage nurse by

arriving patients.

RVP.uTirageTime()

uPatientClassification type designation (CW or NIA) ofarriving patients

RVP.uPatientClassification()

uTreatTimeCW duration of the treatment provided bya doctor for CW patients

RVP.uTreatTimeCW()

uTreat1TimeNIA duration of first treatment provided bya doctor for NIA patients

RVP.uTreat1TimeNIA()

uTreat2TimeNIA duration of second treatment providedby a doctor for NIA patients

RVP.uTreat2TimeNIA()

uLabTestTime(t) duration of diagnostic tests undertakenby NIA patients

RVP.uLabTestTime()

uNeedTest TRUE when NIA-patient needs a

diagnostic test and false otherwise.

RVP.uNeedTest()


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Annex AData Modelling

TABLE 1 Acquired Data Modelling Information

Feature Outcome of Data Analysis

Arrival rate of UCC

patients

Exponential distribution with mean of 30 minutes

Triage processing time Between 5 and 15 minutes

CW vs NIA distribution 45% of patients fall into the CW category while 55% fall into the

NIA category

Treatment time for CW

patients

Normal distribution with mean = 30 minutes and variance = 15

Treatment time (first)

for NIA patients


Percentage of NIA

patients requiring

diagnostic tests

75%

Treatment time (second)

for NIA patients


UCC_ProjectGoalsHighLevelCM.pdf

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