Evaluating Trauma Literature

Chapter 72 Evaluating Trauma Literature



David C. Chang, MD



INTRODUCTION


In some surgical specialties, new procedures and guidelines are frequently developed and adopted based on uncontrolled case series, despite the fact that selection bias often appears in these series (to select the “best” possible surgical candidate patients to demonstrate the feasibility of the new procedure). This bias makes the results difficult to generalize to the “average patient.”


In contrast, conclusions based on carefully analyzed evidence in the literature have played an ever-increasing role in the development of clinical guidelines in trauma care. The most prominent early example of evidence-based guidelines in trauma grew out of important work performed by the Brain Trauma Foundation, in collaboration with the American Association of Neurologic Surgeons.1 Guidelines were developed around 13 specific clinical issues in patients with severe traumatic brain injuries.


In highlighting the importance of evidence-based surgical practice in trauma, this chapter emphasizes specific pitfalls to be avoided in evaluating the trauma literature. The example of the evolution of management of traumatic colon injuries are utilized to illustrate the pitfalls.



PITFALL 1: GENERATING A CLASS I RECOMMENDATION BASED ON CLASS III DATA


In 1943, the Surgeon General of the United States issued guidelines that all colon injuries sustained by soldiers in the North African theater during World War II be managed by colostomy either at or proximal to the site of injury, rather than by primary repair or resection and anastomosis.2 Retrospective analysis of this recommendation included the observations that colon injuries during the Civil War carried an associated 90% mortality, whereas those experienced during World Wars I and II carried a 60% and a 30% mortality, respectively. The reduced mortality of injuries experienced during World War II was attributed to the policy of mandatory colostomies, ignoring the contribution of advances in fluid resuscitation, plasma preservation, blood-banking techniques, the availability of antimicrobial agents, and superior military triage and evacuation.





• Consequence



For the two decades after World War II, the military mandate led to the assumption in civilian practice that colostomy should be the standard of care for traumatic colon injuries. This led to thousands of patients receiving colostomies and the need for subsequent operations with their associated morbidity. Tradition and intuition would play a large role in the choice of management until Stone and Fabian published a report in 19793 comparing the outcomes of colostomies versus primary repair in patients with less severe injuries.


• Repair/Prevention



The prevention of future misassumption is hopefully feasible with the development of the principles of evidence-based medicine. These principles dictate that class II (prospective nonrandomized) and class III (retrospective) data should generate questions rather than answers. Once the feasibility and estimated complication rates of two possible treatment arms (colostomy/diversion versus primary repairs/anastomosis) are established, the development of clinical guidelines should ideally be derived from well-designed prospective, randomized trials. In retrospect, attributing the decreased mortality from colon injuries in World War II to the policy of mandatory colostomy was probably unfairly indicting primary repair and unduly promoting colostomies.


PITFALL 2: INAPPROPRIATE COMPARISON OF COMPLICATION RATES BETWEEN RETROSPECTIVE AND PROSPECTIVE SERIES


When a clinical researcher and a study nurse formally define complications (such as intra-abdominal abscess after colon repairs) and prospectively compile them, the magnitude of the complication rates will almost always be higher than the complication rates generated by chart reviews and retrospective recall. An example of a remarkably low complication rate generated by retrospective methodology is seen in a 1984 study of traumatic colon injuries at an urban trauma center.4 In this series of 56 patients over a 6-year period, none developed an intra-abdominal abscess. These incredible results raise the question as to whether more severely injured patients who developed complications somehow eluded the investigators’ chart reviews. Subsequent retrospective series published over the ensuing decade would echo a near 0% septic complication rate among patients undergoing primary repair of penetrating colon injuries.5,6 Interestingly, these excellent outcomes are unattainable when the same patients are evaluated prospectively.7,8





• Consequence



Patients, malpractice attorneys, hospitals, and performance-improvement committees may well develop the unreasonable expectation that the management of traumatic colon injuries carries a 0% septic complication rate.

Related posts:

  1. Isolated Limb Perfusions and Extremity Amputations
  2. Lateral Pancreaticojejunostomy (Puestow) Procedure
  3. Left Colectomy: Open and Laparoscopic
  4. Bronchial and Vascular Sleeve Lobectomy

Stay updated, free articles. Join our Telegram channel
Tags:
Jun 21, 2017 | Posted by in GENERAL SURGERY | Comments Off on Evaluating Trauma Literature

Full access? Get Clinical Tree
Get Clinical Tree app for offline access