Isolated Free Fluid on CT after Blunt Abdominal Trauma
ABSTRACT & COMMENTARY
Source: Cunningham MA, et al. Does free fluid on abdominal computed tomographic scan after blunt trauma require laparotomy? J Trauma Inj Infec Crit Care 1998;44:599-603.
Cunningham and associates looked at three years of data from their trauma registry (3281 patients). Of those, 798 had abdominal CT scans and 126 patients had positive findings on CT scan. Of those 126, 31 patients had isolated free fluid as the only finding on CT scan (no evidence of solid organ injury, no extravasation of contrast). All 31 patients were taken to laparotomy. The laparotomy was considered therapeutic in 29 of these 31 patients. The most common finding at laparotomy was bowel injury (18 patients or 51%); 14 patients had small bowel injuries, seven had colon injuries, and three had both. Major mesenteric injuries were the next most common operative findings. Five patients had intraperitoneal bladder rupture, and two patients had solid organ injuries not detected by CT scan.
Cunningham et al concluded that the presence of isolated free fluid on abdominal CT scan in patients with abdominal trauma is highly predictive of the need for laparotomy. They suggest further that this finding is a marker for injury to the bowel or mesentery, both difficult injuries to diagnose preoperatively.
COMMENT BY GLENN C. FREAS, MD, JD
This study has some striking results in addition to the major conclusion. One finding was the low incidence of positive CT scan findings in general (126/798 or 16%). In the question and answer session after this paper was presented, the lead author admitted that they were "still in the learning phase" on the use of ultrasonography in evaluating patients with abdominal trauma. This study is one in a long line that points to the need for all of us in emergency medicine and trauma surgery to become skilled in this simple, inexpensive, bedside modality.
Importantly, this study made no attempt to correlate physical findings with the CT scan results. Further, there is no mention of the time from CT scan to the time of decision to take the patient to the operating room. How many of these decisions were prompted by a change in the patient's clinical examination or stability, and not the finding of free fluid on CT scan? In the question and answer phase, commentators mentioned two other papers which found that this subset of patients with isolated free fluid on CT scan had therapeutic laparotomy rates of only 10-20%.
Perhaps some of this discrepancy can be reconciled by a selection bias in this study. Cunningham et al only included patients who qualified for inclusion in the trauma registry. During the study period, there was a total of 6059 trauma patients admitted. Only slightly greater than one-half were enrolled in the study. I suspect that patients in the registry were sicker and stayed in the hospital longer. It would be interesting to know how many of the non-registry patients had isolated free fluid on abdominal CT scan and the scope of their injuries.
Despite the above points, I think this study is useful. Patients with isolated free fluid on abdominal CT scan, particularly those who have physical findings or significant associated injuries, appear to be at risk for intra-abdominal injuries. This study suggests that an aggressive approach of taking these patients to the operating room may be warranted.
You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
- Award-winning Medical Content
- Latest Advances & Development in Medicine
- Unbiased Content