In order to plan the daily routine of a surgical day care unit optimally and effectively, it is indispensable to know the causes of unanticipated admission of outpatients. The purpose of this experiment was to evaluate the influences and predictors of unanticipated admission of patients in our day care unit for ambulatory surgery. The data sets of 3152 surgical outpatients were evaluated. The duration of stay had been entered online by computers.
Method: From January 1997 until June 1999, all clinically relevant parameters from any outpatient were entered into an anesthesia information management system (NarkoData, Imeso GmbH, Hüttenberg-Rechtenbach, Germany). The correlation of potential nominal and ordinal scaled predictors of unanticipated admission was tested using the chi-squared test. Univariate analysis was used in determining predictors for the occurrence of unanticipated admission. Pearson's contingency coefficient (CC) was used as a standard for the correlation rigidity in nominal and ordinal scaled parameters. The correlation standard eta was used for metrical parameters.
Results: Unanticipated admission occurred in 169 (5.4%) of the 3152 outpatients. The following parameters significantly influenced unanticipated admission: age, ASA status, diagnosis (ICD-9), time of admission, different anesthesia procedures and anesthetics (opioids and non-depolarizing muscle relaxants), surgical department, type of surgery (ICPM), duration of operation, blood loss, intraoperative hemoglobin values, and the administration of colloid and crystalloid solutions. The parameters blood loss, intraoperative hemoglobin values, and administration of colloid solutions were evaluated as being good predictors.
Conclusion: The causes of unanticipated admission of patients in our day care unit for ambulatory surgery are manifold. Some relate to the patient, the anesthesia, and the organization of the day care unit, whereas lengthy operative trauma leading to intraoperative blood loss also plays a major role.