Use of the ‘Queuing Theory’ and Patient-Based Characteristics to Assess the Performance of a Paediatric Intensive Care Unit

Abstract

The performance of an intensive care unit (ICU) is the prompt admission of patients with specific conditions and institution of appropriate management leading to expected outcomes within the expected time. Therefore, assessment of ICU performance generally involves selection of appropriate indicators in patient-, institutional- and environmental- based characteristics and their application in relevant mathematical models. Unfortunately, these models are often too complex and not easy to adopt in different situations. Here, a simple method using the 'queuing theory' and patient-based characteristics to gauge the performance of a Paediatric Intensive Care Unit (PICU) is described. This was a ten year retrospective study to determine the queuing nature and patient based characteristics in the PICU using records of patients who were prescribed antibiotics from January 1998 to December 2007. The daily arrival rates and length of stay were used in the queuing simulation formula to derive the appropriate parameters. It was established that 63% of the PICU was utilised by patients who stayed for 7.48 ± 6.8 days. The ICU admitted mainly children and infants of low body weight, with a variety of medical and surgical problems and experienced many complications while in the PICU. These patients were successfully managed, whereby most patients improved, leading to a low mortality rate of < 5%. In conclusion, the queuing theory was successfully used to evaluate the performance of the PICU (ICU utilisation, type of patients admitted, common conditions and length of stay) and to recommend appropriate remedial measures. The model is simple and can be used in other ICUs.