Research analysis: How delays in transport impact functional outcome

The association between prehospital time and outcome of trauma patients in 4 Asian countries: A cross-national, multicenter cohort study


A retrospective cohort study examining how prehospital time affected mortality and functional outcomes in trauma patients was recently published in the journal “PLOS Medicine.”

The study, “Association between prehospital time and outcome of trauma patients in 4 Asian countries,” included 21,886 individuals from the Pan-Asian Trauma Outcomes Study (PATOS). Patients from Japan, Taiwan, Malaysia and South Korea were included if they were transported by EMS to the hospital within the time period of Jan. 1, 2016, to Nov. 30, 2018.

Data collected included age, sex, mechanism of injury, prehospital airway management, fluid access and injury severity. The injury severity score (ISS) was calculated by summing the square of the three highest Abbreviated Injury Scale (AIS) scores for injuries to different body regions. Additionally, a triage score, RTS, was calculated using the recorded Glasgow coma scale, systolic blood pressure and respiratory rate. Functional status at discharge was assessed using the Modified Rankin Scale (MRS), a standard questionnaire completed by the physician.

The authors found that patients who received circulatory access or a rescue airway had (a non-significant) increase in odds of 30-day mortality and poor functional outcomes. However, there are many possible confounding factors, including injury severity, personnel experience and EMS judgment.
The authors found that patients who received circulatory access or a rescue airway had (a non-significant) increase in odds of 30-day mortality and poor functional outcomes. However, there are many possible confounding factors, including injury severity, personnel experience and EMS judgment. (Photo/Will.alexander, Wikimedia Commons)

Of the participants, 280 patients (1.1%) died within 30 days of their injury, with significantly higher mortality in older patients and those with:

  • Non-penetrating injury (99.3% mortality)
  • Traumatic brain injury (33.6% for isolated TBI, 40% for mixed TBI)
  • Major trauma (66.1% ISS >16 and 74.6% RTS<7)

Time of injury to time of EMS arrival on scene (RT), was shorter in geriatric patients. Time of EMS arrival on scene to arrival at the ED (SH), was longer in:

  • Geriatric patients
  • Those who received an airway (median time of 27 versus 21 minutes)
  • Patients with an ISS>16 (median time of 23 versus 21 minutes)

All patients who received IV or IO access had significantly longer RT and SH times. The majority of patients with 30-day mortality had a shorter time of injury to time of EMS arrival to hospital (TPT) (median of 41 vs 47 minutes) while patients with poor functional outcomes had longer median TPT (56 vs 48 minutes).

Logistic regression revealed that RT and TPT weren’t associated with increased risk of 30-day mortality, while a long SH increased risk at a non-statistically significant level. Other variables associated with increased odds for mortality included:

  • Older age
  • ISS>16
  • Use of a rescue airway
  • Establishment of circulatory access

Increased TPT was associated with an increased risk of poor functional outcome in patients of all ages, sexes and those with or without TBI. TPT wasn’t significantly related to functional outcome in Japan, Malaysia or in patients with penetrating injury, ISS>16 and RTS<7.

Memorable quotes about prehospital time and survivability

Here are three memorable quotes from the study.

“We found no association between prehospital time and 30-day mortality in trauma patients. However, increased TPT, RT or SH may be associated with increased risk of poor functional outcome.”

“We support the concept of the ‘golden hour’ for trauma patients, emphasizing rapid transportation so that they receive timely definite care.”

“Functional outcome, which is an index of neurological status, may predict quality of life and the ability to return to normal life and work. Therefore, it is also an important index of outcome, and achieving a favorable functional outcome should be a priority in patient care.”

Top takeaways on prehospital time and trauma outcomes

Here are two takeaways from the study, “Association between prehospital time and outcome of trauma patients in 4 Asian countries:”

1. “Golden Hour” for trauma patients

Although the study found that prehospital time did not affect 30-day mortality, prehospital times longer than 50 minutes did cause poor functional outcomes. The odds of a poor functional outcome increased by 6% with every 10-minute delay in TPT (time of injury to arrival at hospital).

In this study, functional outcome was defined as an index of neurological status, which may predict ability to return to normal life. Therefore, although the risk of death itself may not increase with longer prehospital times, poorer neurological outcomes are more likely when on scene and transport time are extended.

2. No definite answer for load and go versus stay and play

The authors found that patients who received circulatory access or a rescue airway had (a non-significant) increase in odds of 30-day mortality and poor functional outcomes. However, there are many possible confounding factors, including injury severity, personnel experience and EMS judgment. Ultimately, it becomes a judgement call for on-scene providers to determine what interventions are needed at the time with the caveat that a shorter scene and transport time will most likely be more beneficial for the patient.

Additional resources on prehospital trauma assessment

Learn more about EMS treatment and transport of trauma victims with these resources:

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