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Three Part Question

[In patients presenting to the emergency department with blunt abdominal trauma] is [there a place for oral contrast, in conjunction with CT] in [identifying life threatening intra-abdominal pathologies]

Clinical Scenario

A 19 year-old girl was brought in having fallen off her horse at a canter and kicked in the abdomen. An ED trauma call was initiated. She was alert, orientated, stable but tachycardic. She had external bruising to her abdomen and it was tender on palpation, a training FAST scan was negative. Analgesia was given and the tachycardia remained. A CT abdo was requested. The consultant radiologist insisted that oral contrast was given. I wondered whether giving oral contrast improved images and diagnosis enough to outweigh the delay to scan as well as the hazards of giving oral contrast.

Search Strategy

Medline 1950/10 using the OVID interface.

{exp abdominal injuries AND exp Tomography, X-ray Computed AND exp Contrast Media} LIMIT English language and humans

Search Outcome

There were 18 articles which I read through, of which seven were relevant.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Stafford RE et al 1999 USA	394 patients with blunt abdominal trauma. Average age 36 years. Oral contrast (OC) vs no OC.	RCT	Nausea and vomiting	Vomiting in 12.9%: no change between groups	Small numbers of small bowel injuries. Limited study power.
			Abnormal CT results	105 abnormal scans (50 OC and 55 no-OC)
			Need for laparotomy	33 abnormal scans had laparotomies (19 OC vs. 14 no OC). One scan per group was non-therapeutic
			Missed GI tract and solid organ injuries	1 missed Small bowel injury in non-OC group (sensitivity 86%), non missed in OC group (100%). Sensitivity for solid organ injury 84% OC, 88.9% non-OC. Specificity for solid organ injury was 94% OC group and 57.1% no-OC group
			Time to Scan	Time to scan 39.02+/-18.73 mins with no OC, 45.92 +/- 24.17 mins in OC group
Allen TL et al 2004 USA	500 consecutive adult, blunt ‘trauma 1’ patients from July 2000- November 2001. All imaged with iv contrast not oral	Diagnostic cohort	Blunt bowel & mesenteric injuries (BBMI) diagnosed on CT. True BBMI diagnosed at laparotomy or autopsy.	20 patients had True BBMIs . 19 of these patients were identified on CT. Sensitivity 95%. There was 1 false negative. 480 patients proved to have no injury to the bowel or mesentery. 478/480 were identified on CT. Specificity 99.6%. There were 2 false positives.	retrospective small numbers with pathology
			3 month follow up phone call	No patients found to have missed injury at the 3 month follow up call
Tsang BD et al 1997 USA	124 patients notes from 2192 who presented with abdominal trauma and had an abdominal CT, admitted between 1st June 1988 and 1st Nov 1993. Age 28 +/- 15.7 years	Diagnostic cohort	the frequency at which OC contributes to diagnostic value of abdo CT for trauma. The value of OC in intestinal and pancreatic injuries.	All spleen and liver injuries were correctly diagnosed prospectively by CT. All these could have been diagnosed in the absence of OC. All patients sent home with no intra-abdominal injury had CTs read as normal. OC judged essential in none. 1 of 22 intestinal/mesenteric injuries was diagnosed on CT. It was judged that this case could have been seen without OC. The other 21 were diagnosed surgically, none were diagnosed prospectively by CT. No CT scans showed free air or contrast extravasation in the 7 cases of intestinal perforation. Only 2 CTs were found in which OC was thought to be essential. Both with Pancreatic injuries. (one was a false positive result though). There were two other pancreatic injuries diagnoses at laparotomy and these had normal CTs.	Retrospective study Selection bias (from the surgeons) Volume of OC used was large (1000ml) This study used subjective ‘professional opinion’ as the main judgement, retrospectively, of whether OC was necessary or not. They included patients aged 7 weeks to greater than 65 years
			the delay to CT with OC	CT was delayed by an average of 2 hours with the OC.
			the SE of OC administration	OC had SE- placements of NGTs, vomiting and aspiration
Stuhlfaut JW et al 2004 USA	CT reports (Oct 01- Sept ’03), from 1082 adult (18 years or older) patients, were reviewed. 765 men/ 317 women (no patients received OC)	Diagnostic cohort	Negative CT findings	932 patients had a normal CT scan (i.e. no intra-abdominal injury seen). 1 patient in this group went on to have surgery for a perforation (not visible on CT) i.e. 1 false negative	Retrospective small numbers with intra-abdominal pathologies.
			Solid organ injury with or without haemoperitoneum	102 patients had solid organ injury with or without haemoperitoneum. 26 of these patients required surgery. 25/26 showed no viscera/mesenteric injury at laparotomy.
			CT showing only free fluid	34 patients showed free fluid. 21 managed conservatively, 7 had surgical exploration (no injury identified), 6 had repeat CT with OC within 48 hours of admission (one had negative laparotomy others no change)
			CT considered suspicious for bowel or mesenteric injury	14 CTs were suspicious for bowel or mesenteric injury. At laparotomy 9/14 patients had confirmed injuries. (5 false positives)
			Followed these CT diagnoses through hospital course to find out sensitivity and specificity of CT without OC.	1066 true negatives,9 true positives, 2 false negatives, 5 false-positives on CT interpretation. Sensitivity for MDCT for identification of bowel or mesenteric injury requiring surgical repair was 82%. Specificity was 99%. Positive predictive value 64%. Negative predictive value 99%
Shankar et al 1999 UK	101 children (72 boys, 29 girls) who had abdominal trauma between 1993- 97. Median age 9.5 (range 1.5- 16.5) notes review	Diagnostic cohort	Abdominal CT was positive if there was evidence of solid organ injury, intraperitoneal fluid of air, retroperitoneal haematoma.	57 (vs. 44) patients received OC. 3 children then received contrast in a further scan. 34 children had positive CT scans. 30/34 had solid organ injury. 3/30 required laparotomy (which confirmed CT findings). 2/60 suspected intestinal injury on CT (OC), 1/2 had injury at laparotomy. 2/44 suspected intestinal injury on CT (no OC), 2/2 had injury at laparotomy. 1 child had 2 negative CTs (1 without then the 2nd with OC). Laparotomy done (clinical findings) and showed perforation.	Medical records review Small numbers in some groups retrospective
Clancy TV et al 1993 USA	492 identified from Trauma registry who had CTs for blunt trauma between Jan 1988 and Dec 1991 65% male Mean age 32.2 OC used in 8 patients (2%)	Diagnostic cohort	Operative procedures	372 patients had negative CT scans. 1 missed bowel injury (76%). 120 patients had positive scans (24%). 42 had abdominal surgery; 2 correctly diagnosed bowel injury and 2 false negative bowel injuries (of note during laparotomy there were 4 previously unseen injuries identified). 78 patients (with positive scans) had no abdominal surgery and there were no late bowel injuries in this group.	retrospective no real comparison between no-OC and OC CT defined outcome measures such as LOS and mortality but did not really discuss these or go into much detail.
			Length of stay (LOS)	LOS significantly longer among survivors.
			mortality	37 deaths (7.5%)- 29 of which were caused by Head Injury.
			false negative and false positive scans	Sensitivity CT scan 98.4%. Specificity CT scan 99.8%
Koroglu et al 2004 USA	A single case report of a 37 year old man. MOI- RTC	Case Report	Surgery	This patient had a CT with iv but no oral contrast which was negative for intra abdominal pathology. A second CT with oral contrast then occurred which showed a diaphragmatic rupture and he underwent surgery. He remained haemodynamically stable throughout.	single case

Comment(s)

The difficultly with this BestBET is that there have been huge advancements in CT now which make the scanning techniques, of even a few years ago, almost obsolete. I guess the reassuring thing though is that even in the older papers, without our new MDCT-ways, there was no place, in the acute presentation, for the use of oral contrast prior to CT. All studies suffered from a low incidence of intra-abdominal pathologies.

Clinical Bottom Line

MDCT alone is an excellent negative predictor. The use of oral contrast with CT, in the acute setting, in patients with blunt abdominal trauma, is not indicated.

Level of Evidence

Level 2 - Studies considered were neither 1 or 3.

References

1. Stafford RE, McGonigal MD, Weigelt JA, Johnson TJ. Oral contrast Solution and Computed Tomography for Blunt Abdominal Trauma, A Randomised Study Archives of Surgery 134(6):622-6; discussion 626-7,1999 Jun
2. Allen TL, Mueller MT, Bonk RT, Harker CP, Duffy OH, Stevens MH Computed Tomographic Scanning without oral contrast solution for blunt bowel and mesenteric injuries in abdominal trauma Journal of Trauma-Injury Infection and Critical Care 56(2):314-22, 2004 Feb
3. Tsang BD, Panacek EA, Brant WE, Wisner DH Effect of oral contrast administration for abdominal computed tomography in the evaluation of acute blunt trauma Annals of emergency medicine 30(1):7-13, 1997 Jul
4. Stuhlfault JW, Soto JA, Lucey BC, Ulrich A, Rathlev NK, Burke PA, Hirsch EF Blunt abdominal Trauma: Performance of CT without Oral contrast material Radiology 233(3):689-94, 2004 Dec.
5. Shankar KR, Lloyd DA, Kitteringham L, Carty HM. Oral contrast with computed tomography in the evaluation of blunt abdominal trauma in children British Journal of Surgery 86(8):1073-7, 1999 Aug
6. Clancy TV, Ragozzino MW, Ramshaw D, Churchill MP, Covington DL, Maxwell JG Oral Contrast is not necessary in the evaluation of Blunt abdominal trauma by computed tomography American Journal of Surgery 166(6):680-4; discussion 684-5, 1993 Dec
7. Koroglu M, Ernst RD, Oto A, Mileski WJ Traumatic diaphragmatic rupture: can oral contrast increase CT detectability? Emergency Radiology 10(6):334-6, 2004 Jul