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Observation unit admission as an alternative to inpatient admission for trauma activation patients
  1. T E Madsen,
  2. J R Bledsoe,
  3. P J Bossart
  1. University of Utah, Salt Lake City, Utah, USA
  1. Dr T E Madsen, University of Utah, 30 N 1900 E 1C26, Salt Lake City, UT 84132, USA; troy.madsen{at}


Background: At this 35 000 visits/year emergency department (ED) at a level one trauma centre, a trauma protocol was implemented for the ED observation unit. Data on all trauma observation unit admissions were then collected to evaluate for safety, efficiency and admission rates.

Methods: A retrospective chart review was performed of all trauma patients in the observation unit during a 14-month period. Exclusion criteria for observation unit admission included: abnormal vital signs, positive focussed abdominal sonography for trauma examination, abnormal ECG, abnormal chest radiograph, abnormal head computed tomography, Glasgow coma score less than 14, or multisystem trauma.

Results: 364 trauma patients were admitted to the observation unit. 84.6% were trauma II activations and 3.8% were trauma I activations. There were no deaths, intubations, loss of vital signs or other adverse events. The average length of stay was 12 h 46 minutes and 11.5% of patients were admitted to an inpatient unit. At 30-day follow-up, there were no significant missed injuries.

Conclusion: The observation unit is a safe alternative to inpatient admission for the evaluation of the minimally injured trauma activation patient.

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Emergency department (ED) observation units continue to gain attention in the medical literature. Many observation units began as evaluation centres for low-risk chest pain patients. Several previous studies have described the success of these units in evaluating and risk-stratifying chest pain patients13 as well as patients with transient ischaemic attacks, dehydration and asthma.46

Previous published literature has not reported the use of an observation unit for all types of trauma patients. There have been small studies reporting observation unit admission of specific groups of trauma patients.7 8 Our goal was to evaluate the utility and safety of an observation unit protocol for all trauma patients evaluated in our level I trauma centre.

Box 1 Trauma activation criteria

Level one

Systolic blood pressure <90 mm Hg or requiring blood products during transport

Glasgow coma score <12

Respiratory rate >30 or <8 breaths per minute

Gunshot wound to the head

Open pelvic fracture

Penetrating injury proximal to the knee or elbow

Pulseless extremity

Traumatic paralysis

Flail chest

Airway difficulty or intubation

Level two

Glasgow coma score ⩽14

Amputation proximal to wrist or ankle


Fall >20 feet

Auto–pedestrian accident

Motorcycle collision with separation or >20 mph

Age <5 or >65 years

Trauma with burn

Multiple fractures or open fractures

Pelvic fractures

Crush injury

Motor vehicle collision with ejection

Interhospital transfer <24 h after injury

Intubated trauma patients not meeting trauma 1 criteria

Non-trauma activation with positive focussed abdominal sonography for trauma examination


The University of Utah is a level I trauma centre in Salt Lake City, Utah. Trauma presentations to the ED include all types, with the majority being blunt trauma from motor vehicle accidents. The ED and trauma team have predefined criteria for trauma activation (box 1). In April 2006, the ED opened an observation unit, which included a protocol for the evaluation of trauma patients.

Admission to the observation unit was at the discretion of the trauma team and the attending emergency physician. The protocol was created to be tailored to the individual trauma patient. Patients generally received intravenous fluids, pain medications, vital signs monitoring and serial haematocrit testing. Additional components of the protocol include regular neurological examinations and possible repeat head computed tomography (CT) scan for head injury patients, vascular/neurological examinations for patients with orthopaedic injuries, serial abdominal examinations for patients with abdominal trauma and repeat chest x ray for patients with chest trauma. Trauma patients were excluded from observation unit admission if they had abnormal vital signs, a positive focussed abdominal sonography for trauma examination, abnormal ECG, abnormal chest radiograph, Glasgow coma score (GCS) less than 14, or multiple system injury involvement.

We performed a retrospective chart review of all patients placed in the observation unit under the trauma protocol from 1 April 2006 to 31 May 2007. The study received approval from the hospital’s institutional review board in October 2007. Fourth-year medical students, all of whom had worked in the ED before the study, reviewed all charts of trauma patients admitted to the ED observation unit during the study period. Using a template form, they recorded patient characteristics, injuries, length of stay, adverse outcomes (loss of vital signs, intubation, or death), and whether these patients were ultimately discharged from the hospital or admitted to an inpatient unit. For discharged patients, we recorded any ED visits in the 30 days following the initial ED visit and any additional injuries identified during these visits.

For quality assurance purposes, one of the study’s lead investigators (JB) performed a review of 20% of all charts reviewed by the research associates. Descriptive statistics were used to describe the characteristics of the trauma patients admitted to the observation unit, as well as outcomes (SPSS version 16.0).


During the 14-month period, 364 patients were admitted to the ED observation unit under the trauma protocol; 84.6% had initially presented as trauma II activations, 3.8% as trauma I activations and 11.6% had received a consultation from the trauma service while in the ED, but had not met the initial criteria for trauma activation. The average patient age was 35.4 years and 66% of patients were male; 92.6% of injury mechanisms were categorised as blunt and 7.4% as penetrating. The most common specific injury mechanisms were motor vehicle accident, fall and skiing/snowboarding injuries (table 1).

Table 1 Mechanism of injury for observation unit patients

Patients placed in the observation unit carried a variety of trauma-related diagnoses, the most common being closed-head injury, laceration or penetrating wound and extremity fracture or dislocation (table 2). Patients with intracranial haemorrhage were those with a small amount of intracranial bleeding and a GCS less than 15, which were determined to be non-operative and were placed in the observation unit for repeat head CT and frequent neurological examinations. Patients with pelvic fractures and spinal fractures were also non-operative, stable fractures in patients who required pain control and orthopaedics re-evaluation. Patients had received a trauma evaluation, including trauma surgery examination/consultation, CT scans and x rays, before placement in the observation unit. Additional studies in the observation unit were at the discretion of the trauma service and consulting services.

Table 2 Significant injury diagnoses for patients placed in observation unit

A total of 308 patients (84.6%) had at least two haematocrit levels drawn during their observation stay. Additional studies performed in the observation unit included: CT scan (19 patients), x ray (48 patients), both CT scan and x ray (nine patients) and magnetic resonance imaging (19 patients). Average observation unit length of stay for trauma patients was 766 minutes (12 h 46 minutes); 11.5% of patients were ultimately admitted from the observation unit to an inpatient hospital service for further inpatient care.

Additional injuries identified during the observation unit stay included: subdural haematoma, liver laceration, lumbar and thoracic spine fractures, bowel perforation and splenic laceration (one patient each). Patients with these diagnoses recognised in the observation unit were admitted to an inpatient unit. Additional patients admitted were at the discretion of the trauma service and were generally for pain control. There were no deaths or adverse outcomes for patients admitted to the observation unit under the trauma protocol.

During the 30 days following patients’ discharge from the observation unit, 17 (4.7%) patients returned to the ED. In only one of these patients was an injury identified that had not been noted during the observation visit: a retained piece of glass in a laceration. No other additional injuries were identified and none of these patients required hospital admission or placement in observation upon return to the ED.


In our experience, it was feasible to create and implement an observation unit protocol for the evaluation and treatment of trauma patients. ED and trauma directors may wish to consider creating protocols for treatment of trauma patients in ED observation units.



  • Competing interests: None.

  • Ethics approval: The study received approval from the hospital’s institutional review board in October 2007.