Project Management Institute

Implementation of the unit-dose drug distribution system using the critical path method


Kingston General Hospital

Unit dose is a drug distribution system that provides the prescribed dose of a specific drug for a certain patient at a specific time. It differs from other systems in that each dose of a prescribed drug is packaged individually, in a ready-to-administer form. Each package is labeled so that it retains its identity right up to the time it is administered to the patient. The package, labeled with the drug’s generic name, strength, control number, and expiration date virtually eliminates contamination resulting from transfer and handling of the drug. Unused medications can safely be reissued. In addition, the system sharply reduces the potential for medication errors.

Several hybrids of the system are employed in hospital pharmacy departments across Canada. The system was approved for use at Kingston General Hospital (KGH) in early 1976. The KGH system employs a medication cart containing individual patient bins. Daily medication requirements are held in these medication bins or drawers. Utilizing a medication drawer exchange system, the pharmacy replenishes patients’ drug requirements once or twice in a 24-hour period.

Planning a unit-dose system for a new hospital is relatively simple compared to converting an existing facility to a unit-dose pharmacy. In the case of an existing hospital, not only must current layout, policies, procedures, forms, and habits be changed, but the operation of the pharmacy cannot stop or miss a beat in the process.

The critical path method (CPM) is a well-known management tool which is used extensively for planning projects of different magnitudes. It is a flexible and dynamic tool that can be used effectively for planning immense projects such as Expo ‘67 and for small projects such as the implementation of a unit-dose drug distribution system. CPM is a method of putting a plan down on paper so that the interrelationships are clearly shown. At its most sophistocated level, CPM can be computer-based for project update and reporting purposes. Activity timings can be expressed as statistical parameters, involving the laws of probability. The critical path is that path through the critical path chart which governs the timing for the project; all activities not on the critical path have some slack or spare time involved with them. At its simplest level, CPM can be used to “get a handle” or “see” a project on paper. Where time is not critical, it may not even be necessary to estimate activity timings; very often, it is the sequence of activities and their interrelationships that are important.

The first step in using CPM was to identify in detail the planning elements of our project.


  • Identify equipment requirements, which include packaging equipment for the different dosage forms of medications (tablets, capsules, liquids, injectables, etc.), floor carts and bins, modular filling stations, patient profile holders.
  • Secure equipment quotes and delivery lead time.
  • Decide on final equipment list (i.e. suppliers).
  • Get equipment budget approval.
  • Order equipment.
  • Allow for equipment delivery lead time.
  • Receive equipment.
  • Set up and modify equipment as necessary.
  • Train pharmacy and nursing staff to use equipment.
Critical path unit dose implementation

Figure.1 Critical path unit dose implementation


  • Identify items to be purchased in unit-dose packages, if any.
  • Decide which items to be packaged in the pharmacy and the type of package (i.e. strip-pak, blister-pak, liquids, injectable, etc.).
  • Identify packaging requirements in terms of items, volume, and package types.
  • Identify bin requirements for unit-dose packaged items storage (size and number of bins and space requirements).
  • Order supplies (mainly packaging supplies).
  • Redefine drug purchasing requirements (mainly size redefinition).
  • Package the initial inventory, using set parameters (i.e. minimum quantity for each packaging process).

Forms and Information Requirements

  • Design a system of prompt notification of patient admission (possible information to include primary diagnosis, allergies, initial orders, etc.).
  • Design the patient medication profile which is the sole medication record for pharmacy and nursing.
  • Design the stock batch control cards (prepackaging record, quality control, and chronological control log).
  • Design a new or modify the existing automatic stop order form, drug clarification form, and the physician order form.
  • Modify nursing-pharmacy notification form (include information such as missing doses, medications not given, surgery cancellation, patient transfer, etc.).
  • Modify I.V. admixture system policies, procedures, and necessary forms and labels.
  • Modify the existing narcotics and controlled drugs procedure.
  • Modify the procedure for patient drugs brought into the hospital.
  • Modify the procedure for the computer-based inventory reporting system.

Space and Layout

  • Secure additional bulk storage space.
  • Plan functions and internal flows (i.e. packaging, cart filling, etc.).
  • Draw block diagrams of layout.
  • Identify modifications and storage requirements (free standing/built-in units, etc.).
  • Make decision on storage units (i.e. manufacture or purchase).
  • Work out schedule for renovations.


  • Compile capital budget (equipment and capital renovations).
  • Compile operational budget (staffing increase, increase hours of operation, supplies, etc.).

Policies and Procedures

  • Change or modify policies and procedures in association with the corresponding forms.
  • Identify different medication types (scheduled, stats, prn, single dose-only, narcotics, pre- and post-op medications, IV’s, anticoagulants, insulins, ointments, eye drops, etc.).
  • Set up ward stock procedure.
  • Allow for temporary patient absence (e.g. weekend leave of absence).
  • Allow for drugs not given.
  • Set up drug administration times.
  • Set up charting of medications.
  • Secure approval for new or modified policies and procedures from administration, nursing, and medical staffs.

Staffing (Pharmacy)

  • Recruitment and hiring
  • Staff scheduling — extension of pharmacy hours
  • Job descriptions, functions in different division and responsibilities

Orientation and Education

  • Pharmacy staff (rotate through a well-organized unit-dose pharmacy for one week each)
  • Medical staff through the pharmacy committee and chiefs of services
  • Nursing staff through an audio visual presentation on the designated units at different times
  • General staff information through the hospital news media

This comprehensive identification of the planning elements is an essential first step to designing the Critical Path Chart (Figure 1). At each circle or “node” on the Critical Path Chart, a set of parameters could be entered such as “earliest finish” or “latest finish.” We decided not to go to the effort of calculating these as broad estimates were sufficient. This is one big advantage of the CPM approach; the system can be used at whatever level of sophistication is demanded by the project. We did specify a time span for the whole project from the time the plan was put into action to the point when the system was operational. We succeeded in meeting this time span. With the plan clearly visible to us, there was no potential for missing any of the steps or miscalculating part of the plan.

We believe that our unit-dose system in the hospital was a success mainly because it was a well-planned project. The use of the CPM was instrumental in the planning phase and it was directly responsible for this success.

*Reprinted with permission from Dimensions in Health Services, journal of the Canadian Hospital Association.

This material has been reproduced with the permission of the copyright owner. Unauthorized reproduction of this material is strictly prohibited. For permission to reproduce this material, please contact PMI.



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