[Lean Six Sigma in the implementation of automated dispensing systems: improving the safe use of medications in thoracic surgery.]

Objective: Medications errors are a major problem that can cause a harm to inpatients. The main objective of the study was to compared medication errors in pharmacotherapeutic process before and after to carried out an intervention: to implant an automated dispensing cabine with to use Lean Six Sigma methodology. The secondary objective was to assess process performance, sigma level and defects per one million opportunities for medication error.

Methods: Quasi-experimental and randomized study carried out in a Thoracic Surgery Unit of a Spanish Hospital. A pharmaceutic recorded and assesed the medication errors detected during pre-intervention period (july-august 2017) and post-intervention period (march-april 2018). The steps analyzed were dispensing, storage and compounding/administration. The pharmacist observed a third of the medication dispensed, stored and compounded/administered during the study period. The observed medication was randomly selected using AleatorMetod.xls software. To perform the statistical analysis, Student's t test and Mann-Whitney U test were used to compare quantitative variables, and Chi-square test for qualitative variables. A significance level of p<0.05 was considered.

Results: The pharmaceutic recorded 4,538 drugs. After intervention, medication errors were decreased a 49% in total pharmacotherapeutic process (12.06% vs 6.15%; p<0.001). In addition, errors were decreased a 91.6% (4.27% vs 0.36%; p=0.004) in the step of medication storage; and a 75.8% (22.52% vs 5.46%; p<0.001) in the step of drugs compounding/administration. However, medication errors were increased in the step of medication dispensing (4.51% vs 15.29%; p<0.001). The process performance increased a 6% (87.9% vs 93.9%), sigma level increased from 2.67 to 3.04 and defects per one million opportunities for medication error decreased a 49%.

Conclusions: To implant an automated dispensing cabinet with Lean Six Sigma methodology helps create a safer environment for the inpatient, reducing medication errors in the steps of storage and preparation/administration, as well as improving the total process performance and sigma level.