To reduce this risk, bed alarms have become ubiquitous at hospitals throughout the US. When a patient is deemed to be at high risk of falling, weight sensitive pads are applied to the bed, chair, or commode. When a patient tries to get up, an alarm sounds in the room and at the nursing station. The alarm reminds the patient to wait for assistance, and alerts nursing staff to assist the patient.
Remarkably, these alarms have become widely used with virtually no evidence that they actually reduce falls, let alone any studies that examine the adverse consequences of restricting mobility. I am not aware of any studies that ask patients how they feel about being attached to these devices. In general, hospitalized older patients are not even asked permission to apply these devices.
This context makes a study by Geriatrician Ron Shorr at the University of Florida particularly remarkable. In a well done study, Shorr provides compelling evidence that these bed alarms fail miserably at their core purpose of preventing falls in high risk hospitalized patients.
To test the usefulness of bed alarms, they did the following. They took 16 medical surgical units at a Memphis teaching hospital and randomly assigned 8 units to a bed alarm intervention and 8 units to usual care. On the intervention unit, the staff received extensive training on the use of the bed alarms and was strongly encouraged to use the alarms on patients felt to be at high risk of falling. Shorr and colleagues compared the rate of falling and fall injury before and after the bed alarm intervention was introduced on both the intervention and the control units. The findings were as follows:
- On the bed alarm units, there were 5.76 falls per 1000 patient days. About 1/4 resulted in injury
- On the usual care unit, there were 4.56 falls per 1000 patient days. About 1/4 resulted in injury
- The trend towards higher fall rates on the intervention units was not statistically significant, so the study does not show that bed alarms lead to more falls. But this trend almost certainly rules out any meaningful chance that this bed alarm system, as implemented in this study, can reduce the risk of falls.
This study raises serious questions about the growing use of bed alarms in US hospitals. As the authors note, these systems are not cheap.
Maybe we need to rethink hospital fall prevention, and focus on more human and less technical solutions. Bed alarms have the potential to be activity restricting. This activity restriction can actually increase the risk of hospital acquired disabilities that are very common in hospitalized elders. Frail older patients need to be encouraged to get out of bed and ambulate. Solutions aimed at getting high risk patients the assistance they need when they need it are likely to be more effective than bed alarms. Also, we need to learn how to make environmental modifications in our hospitals that make it safer when patients actually do fall so that these falls are less likely to cause injury.
So, add bed alarms to the long list of medical interventions that have been widely used despite no evidence that they actually work.
by: Ken Covinsky