title: Intensive care unit alarms--how many do we need?
abstract: OBJECTIVE
  To validate cardiovascular alarms in critically ill patients in an experimental setting by generating a database of physiologic data and clinical alarm annotations, and report the current rate of alarms and their clinical validity. Currently, monitoring of physiologic parameters in critically ill patients is performed by alarm systems with high sensitivity, but low specificity. As a consequence, a multitude of alarms with potentially negative impact on the quality of care is generated.
  
  
  METHODS
  Prospective, observational, clinical study.
  
  
  METHODS
  Medical intensive care unit of a university hospital.
  
  
  METHODS
  Data from different medical intensive care unit patients were collected between January 2006 and May 2007.
  
  
  RESULTS
  Physiologic data at 1-sec intervals, monitor alarms, and alarm settings were extracted from the surveillance network. Video recordings were annotated with respect to alarm relevance and technical validity by an experienced physician. During 982 hrs of observation, 5934 alarms were annotated, corresponding to six alarms per hour. About 40% of all alarms did not correctly describe the patient condition and were classified as technically false; 68% of those were caused by manipulation. Only 885 (15%) of all alarms were considered clinically relevant. Most of the generated alarms were threshold alarms (70%) and were related to arterial blood pressure (45%).
  
  
  CONCLUSIONS
  This study used a new approach of off-line, video-based physician annotations, showing that even with modern monitoring systems most alarms are not clinically relevant. As the majority of alarms are simple threshold alarms, statistical methods may be suitable to help reduce the number of false-positive alarms. Our study is also intended to develop a reference database of annotated monitoring alarms for further application to alarm algorithm research.
authors.affiliation: Department of Internal Medicine I, Hospital of the University of Regensburg, Regensburg, Germany. Sylvia.siebig@klinik.uni-r.de
authors.forename: Sylvia
authors.initials: S
authors.lastname: Siebig
authors.forename: Silvia
authors.initials: S
authors.lastname: Kuhls
authors.forename: Michael
authors.initials: M
authors.lastname: Imhoff
authors.forename: Ursula
authors.initials: U
authors.lastname: Gather
authors.forename: Jürgen
authors.initials: J
authors.lastname: Schölmerich
authors.forename: Christian E
authors.initials: CE
authors.lastname: Wrede
mesh_terms: D056902:Clinical Alarms / Q000592:standards; D019544:Equipment Failure Analysis; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000295:instrumentation; D011446:Prospective Studies; D014741:Video Recording