A Clinical Scenario Raises Important Clinical Questions
Evidence-based medicine (EBM) is the “conscientious explicit and judicious use of current evidence in making decisions about the care of individual patients” . Despite increasing acceptance of the role of EBM in clinical practice over the last two decades,many clinicians are unaware of EBM’s history and do not understand the rigorous systematic approach that the practice of EBM requires.
A 7 year-old male is admitted to the PICU (Pediatric ICU) after being involved in a motor vehicle accident. At the scene he was hypertensive and bradycardic with asymmetric pupils, an irregular respiratory pattern and a Glasgow Coma Score (GCS) of 6. He was intubated in the field and Emergency Medical Services (EMS) personnel attempted to hyperventilate for suspected elevated intracranial pressure (ICP). Upon arrival to the PICU,
he underwent central line placement and was started on an infusion of hypertonic saline and narcotic and benzodiazepine drips for pain and sedation. A few hours after PICU admission, his blood pressure and
heart rate normalized.
This patient’s presentation raises numerous types of questions:
Etiology: By what mechanism does traumatic brain injury cause elevated ICP? Why do patients with elevated ICP demonstrate hypertension, bradycardia and abnormal respirations and how often do these findings present as aconstellation?
Diagnosis: How likely is the constellation of findings (hypertension, bradycardia and abnormal respirations) indicative of elevated ICP? What is the gold standard for diagnosis of diffuse axonal injury following traumatic
Treatment: What is the role of hypertonic saline as an osmotic agent following traumatic brain injury? How does this compare to other osmotic agents like mannitol?
Would induced hypothermia be beneficial for this patient?
Harm: Is hypotension after traumatic brain injury causing hypoperfusion associated with worse neurologic outcomes? Is hyperglycemia harmful?
Prognosis: What predictions can be made about survivability following such an injury? What expectations can be given to the family regarding cognitive outcomes if the child survives?
Questions related to etiology or the “background” of the clinical problem are foundational, focusing on the core of our medical knowledge. Questions related to diagnosis,treatment, harm and prognosis are considered foreground questions and are at the core of EBM. Clinicians often rely
on expertise – their own or those of consultants – to answer the above questions. One problem with reliance on clinical expertise alone is that it can lead to variable and sometimes contradictory guidance, leaving the clinician unclear about the optimal approach. EBM – also known as evidence-based
clinical practice or EBCP – aims to answer foreground questions by integrating the best available evidence with clinician expertise taking into account individual patient preferences and values .