Importance of Nondrug Costs of Intravenous Antibiotic Therapy
Introduction: Costs are one of the factors determining physicians' choice of medication to treat patients in specific situations. However, usually only the drug acquisition costs are taken into account, whereas other factors such as the use of disposable materials, the drug preparation time and the staff workload are insufficiently taken into consideration. We therefore decided to assess true overall costs of intravenous (IV) antibiotic administration by performing an activity-based costing approach.
Methods: A prospective survey on costs and workload by means of a time and motion analysis and activity-based costing was performed in a 605-bed secondary referral centre with 20 intensive care unit beds. The subjects were 50 consecutive patients admitted to our hospital with community-acquired pneumonia or intra-abdominal infections requiring treatment with IV antibiotics. A time and motion analysis of 103 routine acts of preparing and administering IV antibiotics was performed in the intensive care unit and in the Department of Internal Medicine. To measure the entire process an inventory and work flowchart were made using detailed questionnaires completed by members of the nursing staff, the medical staff and the pharmacy staff. In addition, questionnaires were distributed to management and secretarial staff to determine additional overhead costs. The average costs for different methods of IV antibiotic administration were then compared by timing all steps in the process. Four different methods of drug administration were used: administration by volumetric pump, administration by syringe pump, administration by 'unaided' infusion bag, and administration by direct IV injection.
Results: The average times required for each of these procedures, including preparation and administration of the drug, were 4:49 ± 2:37, 4:56 ± 2:03, 5:51 ± 3:33 and 9:21 ± 2:16 min (mean minutes:seconds ± standard deviation), respectively. When the costs for expended staff time and materials (not including drug costs) were calculated this resulted in average costs of €5.65, €7.28, €5.36 and €3.83, respectively, for administration of each dose of antibiotics. These costs represent between 11% and 53% of the total daily costs of antibiotic therapy. Compared with the acquisition costs, these indirect costs ranged from 13% to 113%. Not included in this comparison is the time required for insertion of an IV catheter, which was found to be 10:15 ± 6:31 min with an average calculated cost of €9.17.
Conclusions: Total costs of IV antibiotic administration are formed not only by the costs of the drugs themselves, but also, to a substantial degree, by the time expended by medical and nursing staff, costs of disposable materials and overhead costs. Physicians making decisions regarding the use of specific medications in intensive care unit patients should take these factors into account. Use of IV antibiotics is associated with considerable workload and additional costs that can exceed the acquisition costs of the medications themselves.

A number of studies have suggested that the overall quality of care, outcome, and patient and family satisfaction in intensive care units (ICUs) may be linked to the workload and staffing levels. Budgetary restrictions may play an important role in the organisation of the ICU, and cost reduction is an important issue in intensive care medicine today since ICU costs account for up to 10% of overall hospital expenditure.

Antibiotics are among the most frequently used drugs in intensive care patients, and thus account for a substantial proportion of drug expenditure in ICUs. When performing pharmacoeconomic evaluations of ICU expenditure, it is customary to consider only the direct price of purchasing these medications. To assess the total costs of intravenous (IV) drug therapy in the ICU setting, however, it is necessary to take into account the effect on the workload of nurses and medical staff as well as other health care workers, and to evaluate other costs associated with preparation, administration and monitoring of IV antibiotic therapy. Gaining insight into all the factors that contribute to the actual total overall costs of drug therapy may help increase awareness into what actually drives the costs of hospital services, and to identify opportunities for cost savings.

To assess the costs associated with drug preparation and administration we performed an observational time and motion study in two ICUs in our hospital. For comparison, we also performed this analysis in a general internal medicine ward. The basis of a time and motion study is the measurement, through direct observation by the investigators and the research nurses involved in the study, of staff members performing specific tasks in a process that is subdivided into various components. Indirect costs related to drug therapy, such as costs incurred in assessment of safety and efficacy, were not considered in this study.