Mechanical restraint is a therapeutic procedure commonly applied in acute units in response to psychomotor agitation. Its frequency is between 21 and 59% of patients admitted. These patients represent a risk to both themselves and for health workers. In order to implement measures to prevent agitation and therefore mechanical restraint, it is important to quantify the effects and costs of those procedures. The aim of this study is to determine whether the application of mechanical restraint in psychiatry acute unit is related to a longer stay in hospital.

We reviewed retrospectively the informatics record of all the mechanical restraints made and the total discharges of the three acute care units and dual disorders of our institution, between 2012 and 2015. For every discharge, the presence of at least one mechanical restraint was coded, resulting in two groups. The length of stay of the groups was then compared performing a t-test.

The number of discharges analyzed was 4659 from which 838 had an episode of mechanical restraint associated. There are significant differences between the length of stay of admissions with and without episode of mechanical restraint. The episode of mechanical restraint during an admission is associated with 5 to 9 more days of stay in the unit (P < 0.001).

The performance of a mechanical restraint is associated with a statistically significant and clinically relevant higher length of stay. These results suggest that preventing agitation, and therefore mechanical restraint, would be possible to decrease length of stay, and therefore costs related to hospitalization.

The authors have not supplied their declaration of competing interest.