Emergency care: When the need for evidence is critical


In healthcare, there are many kinds of emergencies — but not all are medical in nature. The emergency may be the urgent need for evidence to help guide important decisions. For a medical emergency, you head to the ER or call 9-1-1. But whom do you turn to for an urgent search and assessment of the medical evidence on a drug or other health technology?

CADTH — an independent, evidence-based agency that assesses health technologies — finds and summarizes the research on drugs, medical devices, and procedures so health care decision-makers can make informed choices. In some cases, this is a lengthy, in-depth assessment taking a year or more. But for others, the need is more urgent. The CADTH Rapid Review service balances scientific rigour with relevance and real-world timelines and provides summaries and critical appraisal of the evidence to decision-makers in as little as 30 days.


Knowing what the evidence is on a health technology is helpful to decision-makers faced with tough decisions. However, in some cases, there is no evidence available or it is limited and of low-quality. But knowing this is helpful to decision-makers as well. Faced with a lack of evidence, decisions may be based on other factors, such as cost or convenience. Decisions might be deferred until more evidence is available. Or, a lack of evidence can lead to discontinuing the use of a drug, device, or procedure if its use is not supported by research.

Many of the rapid assessments that are requested of CADTH focus on trauma, emergency services, and critical care to determine whether there is evidence to support the use of a particular drug, device, or procedure in this care setting. Here is a round-up of recent Rapid Response reports from CADTH in this area.

Treat and release (T&R) protocols allow patients to be treated by emergency medical services (EMS) personnel without being transported to a hospital or referred to a health care facility. Their purpose is to increase the number of emergencies that EMS personnel can respond to without compromising the quality of medical care and to reduce emergency room overcrowding. In the US, T&R protocols have been found to reduce emergency department and inpatient admissions; however, in Canada they are not common. When CADTH reviewed the evidence on T&R protocols, not a lot was found. No evidence-based clinical practice guidelines were identified and only 1 retrospective study abstract was found that met the criteria for inclusion in the review. Based on the limited evidence found, it appears that T&R EMS protocols are safe and effective — but the study involved only patients with supraventricular tachycardia. No evidence was found on T&R protocols for other conditions. T&R protocols may be a promising practice for EMS personnel but evidence is lacking and their implementation in our complex health care system may be difficult.


When a patient has sustained a traumatic brain injury, one of the primary goals of pre-hospital care is to prevent a lack of oxygen to the brain — a major cause of secondary injury to the brain following the initial trauma. A review of the optimal oxygen saturation for traumatic brain injury was requested of CADTH to help guide decisions about oxygen saturation goals for these patients to ensure the best possible outcomes. Evidence was found from two retrospective observational studies and one evidence-based clinical practice guideline. An assessment of the evidence found that higher than normal pre-hospital oxygen levels appear to decrease the chances of surviving in hospital compared with normal oxygen saturations. Oxygen saturation levels of less than 90 per cent are not recommended; however, the maximum safe oxygen saturation level is not known.

The use of a spine board — a board placed underneath a person’s back to immobilize the spine — for suspected spinal cord injuries is a practice that is widely accepted in Canada and around the world. Spine boards for pre-hospital stabilization of trauma patients are intended to reduce the chance of any secondary injury occurring to the spinal cord due to movement during transportation. But despite their widespread use, the way in which they are used varies greatly. Although there are systematic reviews of the evidence involving healthy volunteers, CADTH found a lack of high-quality medical evidence focusing on actual trauma patients to guide how and when spine boards should be used and whether their use is associated with any harms.

Rapid reviews of the medical evidence such as CADTH’s Rapid Response reports can’t answer all the questions that arise in emergency and trauma care. But CADTH Rapid Response reports can go a long way in providing the evidence pieces to the emergency and trauma care puzzle — and can indicate where more research may be needed. Clinicians, policy-makers, patients, and others involved in making important decisions in health care in Canada can access our Rapid Response reports free of charge on our website anytime at www.cadth.ca/RapidResponse.

To learn more about CADTH, visit www.cadth.ca, follow us on Twitter: @CADTH_ACMTS, or talk to our Liaison Officer in your region: http://www.cadth.ca/en/services/liaison-officer.