Significance of Computed Tomography Finding of Intra-Abdominal Free Fluid Without Solid Organ Injury after BluntAbdominal Trauma: Time for Laparotomy on Demand

Ismail Mahmood • Zainab Tawfek • Yassir Abdelrahman • Tariq Siddiuqqi •

Husham Abdelrahman • Ayman El-Menyar • Ammar Al-Hassani •

Mazin Tuma • Ruben Peralta • Ahmad Zarour • Sawsan Yakhlef •

Hazim Hamzawi • Hassan Al-Thani • Rifat Latifi

Published online: 25 December 2013

� Societe Internationale de Chirurgie 2013

Abstract

Background Optimal management of patients with intra-

abdominal free fluid found on computed tomography (CT)

scan without solid organ injury remains controversial.

Objective The purpose of this study was to determine the

significance of CT scan findings of free fluid in the man-

agement of blunt abdominal trauma patients who otherwise

have no indications for laparotomy.

Methods During the 3-year study period, all patients

presenting with blunt abdominal trauma who underwent

abdominal CT examination were retrospectively reviewed.

All hemodynamically stable patients who presented with

abdominal free fluid without solid organ injury on CT scan

were analyzed for radiological interpretation, clinical

management, operative findings, and outcome.

Results A total of 122 patients were included in the study,

91 % of whom were males. The mean age of the patients

was 33 ± 12 years. A total of 34 patients underwent

exploratory laparotomy, 31 of whom had therapeutic

interventions. Small bowel injuries were found in 12

patients, large bowel injuries in ten, and mesenteric injuries

in seven patients. One patient had combined small and

large bowel injury, and one had traumatic gangrenous

appendix. In the remaining three patients, laparotomy was

non-therapeutic. A total of 36 patients had associated pel-

vic fractures and 33 had multiple lumbar transverse process

fractures.

Conclusion Detection of intra-peritoneal fluid by CT scan

is inaccurate for prediction of bowel injury or need for

surgery. However, the correlation between CT scan find-

ings and clinical course is important for optimal diagnosis

of bowel and mesenteric injuries.

Introduction

The early diagnosis of hollow viscus injuries in patients

with blunt abdominal trauma (BAT) is difficult. Further-

more, a delay in the diagnosis of such injuries may be

associated with increased morbidity and mortality [1, 2].

Detection of intra-abdominal free fluid without solid organ

injury also leads to diagnostic dilemma. The presence of

free fluid further indicates the possibility of a mesenteric

tear, a missed solid organ injury, hollow viscus injury, or

fluid leaking from retroperitoneal hematoma associated

with a pelvic fracture [3].

Computed tomography (CT) is the most frequently used

and accepted modality to evaluate hemodynamically stable

patients with BAT [4–7]. However, several studies have

reported missed abdominal injuries involving small bowel

I. Mahmood (&) � Y. Abdelrahman � T. Siddiuqqi �H. Abdelrahman � A. Al-Hassani � M. Tuma � R. Peralta �A. Zarour � S. Yakhlef � H. Hamzawi � H. Al-Thani � R. Latifi

Trauma Intensive Care Unit, Section of Trauma,

Department of Trauma, Surgery, Hamad Medical Corporation,

PO Box 3050 Doha, Qatar

e-mail: traumaresearch@hmc.org.qa;

ismailyousifmah@yahoo.com

Z. Tawfek

Department of Emergency, Hamad Medical Corporation,

Doha, Qatar

A. El-Menyar

Clinical Research, Trauma Surgery Section, Hamad Medical

Corporation, Doha, Qatar

A. El-Menyar � R. Latifi

Weill Cornell Medical College, Doha, Qatar

R. Latifi

Department of Surgery, University of Arizona,

Tucson, AZ, USA

123

World J Surg (2014) 38:1411–1415

DOI 10.1007/s00268-013-2427-5

and mesenteric tears by CT scan in BAT [8–11]. Although

subtle findings such as free fluid, focal fluid-filled thick-

walled bowel loops, and mesenteric infiltration are sug-

gestive of intestinal or mesenteric injury, none with the

exception of free air dictates an exploration [12]. The study

aimed to investigate the outcomes of expected management

of hemodynamically stable patients with abdominal free

fluid demonstrated on CT scan without solid organ injury

after BAT.

Methods

During the study period (January 2008–January 2011), all

patients presented with BAT who underwent abdominal CT

examination were retrospectively reviewed. Demographics,

mechanism of injury, hemodynamic stability (vital signs),

findings of physical examination, CT findings including the

amount of free fluid (mild or moderate, large), details of

operative and non-operative management, and outcomes

were analyzed. Patients with solid organ injury, hemody-

namic instability, penetrating injury, pneumoperitoneum,

and CT findings suspicious for ovarian pathological find-

ings were excluded.

CT scans were performed on Siemens Medical Systems,

64-slice scanners using 120 mL of Omnipaque injected at

3 mL/s. Images through the chest were reconstructed at

1.2-, 2.5-, or 5-mm slice thickness and were analyzed by

consultant radiologist. Intra-abdominal fluid collections

were graded according to the presence of fluid in one or

more of the following spaces: pelvis, perisplenic, perihe-

patic, Morrison’s pouch, left and right paracolic gutters.

Mild or minimal collections were defined as fluid in one

space; whereas moderate collections refers to fluid in two

or more spaces.

The decision for laparotomy was based on the clinical as

well as the radiological findings. Patients were divided into

two groups according to the time elapsed between the

injury and laparotomy. The ‘early laparotomy group’

includes patients in whom surgery was performed within

the first 24 h, whereas the ‘delayed group’ constituted

patients whose surgical procedure was delayed for at least

24 h post-injury. Laparotomy was defined as therapeutic if

measures were taken to repair or resect tissue, or to control

active hemorrhage. Patients managed non-operatively were

kept under observation, and associated injuries were treated

according to their usual standards of care. Successful

observation was defined as a patient who did not require

laparotomy during the hospital admission, or re-admittance

after discharge. This study was approved by the Medical

Research Center (IRB# 10076/10) at Hamad Medical

Corporation, Doha, Qatar.

Data were expressed as percentages, and mean ± stan-

dard deviation, whenever applicable. Two-tailed p values of

\0.05 were considered significant. Multivariate logistic

regression was performed to analyze the predictors of

therapeutic laparotomy, which include age, presence of

bruise, seat belt sign, amount of free fluid in the abdomen

(mild or moderate), associated pelvic fracture, lumbar

spine fracture, and presence of rib fractures. A significant

difference was considered to be when the p value was

\0.05. Data analysis was carried out using Statistical

Package for Social Sciences (SPSS) version 18 (IBM,

Armonk, NY, USA).

Results

A total of 122 patients were included in the study. The

majority (91 %) of the patients were males, with a mean

age of 33 ± 12 years. Motor vehicle crashes (52 %), falls

from height (20 %), and pedestrian hit by motor vehicle

(18 %) were the most common mechanisms of injury

(Table 1). The majority of patients (83.6 %) had a minimal

amount of intra-abdominal free fluid, whereas only 16.4 %

had a moderate amount of free fluid.

Complaints of abdominal pain were observed in 84

(68.9 %) patients. Localized tenderness elicited on an

abdominal examination was found in 75 (61.5 %) patients

(12 with moderate amounts of fluid), and 14 (11.5 %)

patients had diffuse abdominal tenderness (four with

moderate amounts of fluid). Severe head trauma was

observed in 12 (10 %) patients; two required laparotomy

and one was managed with therapeutic intervention. There

Table 1 Descriptive analysis (n = 122)

Male (%) 91

Age (mean ± SD) 33 ± 12

Mechanism of injury (%)

Motor vehicle crash 52

Fall from height 20

Pedestrian injury 18

Abdominal free fluid (volume)

Mild/minimal 102 (83.6 %)

Moderate 20 (16.4 %)

Abdominal pain (%) 68.9

Localized tenderness (%) 61.5

Diffuse abdominal tenderness (%) 11.5

Severe head injury (%) 10

Mortality (%) 1.6

Exploratory laparotomy (%) 28

Non-operative management (%) 72

SD standard deviation

1412 World J Surg (2014) 38:1411–1415

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were two deaths in this study, both due to severe head

trauma. The decision to operate was based on presence of

abdominal free fluid and frequent clinical examination

within 6–48 h.

Exploratory laparotomy was performed in 28 % of cases,

19 % of which had minimal and 9 % had moderate abdom-

inal free fluid. In contrast, 72 % cases were managed

expectantly, and did not require an operation (Table 1). The

operative procedures and the intra-operative findings are

summarized in Table 2. The intra-operative findings showed

mesenteric injury with ischemic small bowel (9.1 %), mes-

enteric tear with ischemia of the sigmoid colon (7.4 %), and

small bowel and/or large bowl mesenteric tears at separate

locations (5.8 %). One patient had combined jejunum and

sigmoid colon ischemia, one patient had ischemic gangre-

nous appendix and one patient had solid organ injury (liver)

that was missed on initial presentation (Table 2). Non-

operative management was successful in all patients and no

complications were observed during the follow-up visits

(7–14 days) in the trauma clinic.

A total of 24 (19.7 %) patients underwent exploratory

laparotomy within the first 24 h (average 5.2 h), five of

whom had wound infection and one had wound dehiscence.

On the other hand, seven (5.7 %) patients underwent sur-

gery after 24 h (average 34 h), three had wound infection,

and one had sigmoid colon anastomosis leak that required

diverting colostomy.

Sustained injury to the lumbar spine, mainly multiple

transverse process fracture (27 %), was frequently

observed, followed by rib (14.8 %) and pelvic (7.4 %)

fractures.

Further, motor vehicle crash-related seat belt injury was

observed in ten patients, nine of whom underwent thera-

peutic laparotomy and one of whom was managed non-

operatively. Multivariate analysis showed that mechanism

of injury (pedestrian injury, odds ratio [OR] 9.5, p = 0.04),

age (OR 1.07, p = 0.07), and presence of seat belt sign

(OR 9.7, p = 0.034) were significantly associated with

therapeutic laparotomy. However, associated injuries such

as pelvic fracture (OR 0.61, p = 0.43), rib fracture (OR

0.29, p = 0.16), and lumbar spine fracture (OR 0.32,

p = 0.18) were not found to be independent predictors for

therapeutic laparotomy (Table 3).

Discussion

CT scan examination facilitates easy detection and quan-

tification of intra-abdominal free fluid, which could be used

as a potential marker of hollow viscus or mesenteric injury

[13]. However, CT finding of abdominal free fluid without

solid organ injury in hemodynamically stable BAT patients

poses a diagnostic dilemma. It may represent an undetected

solid organ injury, bleeding from the mesentery, transu-

dation of intra-peritoneal and retroperitoneal fluid, or a

missed bowel injury, which may be associated with

increased morbidity and mortality [1]. Several investigators

have employed laparotomy to confirm the presence of

Table 2 Amount of fluid, intra-operative findings and operative details

Intra-operative finding Patients Amount of free fluid Procedure

Moderate Mild

Mesenteric injury with ischemic or contusion

of small bowel (jejunum or ilium)

11 5 7 Small bowel resection and anastomosis

with repair of mesenteric tears

Small bowel and sigmoid colon ischemia and contusion 1

Mesenteric tear with ischemia and contusion

of the sigmoid colon

9 4 5 Segmental colonic resection with colostomy

Small bowel and/or large bowel mesenteric

tears at separate locations

7 2 5 Repair of the mesenteric tears

Right colonic ischemia with mesenteric tear 1 1 0 Right colonic resection and anastomosis

Ischemic gangrenous appendix 1 0 1 Appendectomy

Liver tear 1 1 0 Hepatorrhaphy

Table 3 Multivariate logistic regression analysis for predictors of

therapeutic laparotomy

p value Odds

ratio

95 %

confidence

interval

Age 0.007 1.07 1.018–1.125

Mechanism of injurya 0.042 9.527 1.088–83.448

Local tenderness 0.89 0.917 0.269–3.128

Bruise 0.203 2.633 0.594–11.678

Pelvic fracture 0.431 0.609 0.153–2.42

Spine fracture 0.188 0.321 0.059–1.74

Ribs fracture 0.164 0.299 0.029–1.82

Seat belt sign 0.034 9.74 1.184–80.164

Amount of abdominal fluid (mild) 0.007 9.63 1.848–50.276

a Pedestrian injury

World J Surg (2014) 38:1411–1415 1413

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abdominal free fluid (58–80 %) in bowel injury patients for

correlation of CT findings [14, 15]. On the other hand,

others have considered CT scan findings of unexplained

free fluid to scrutinize patients who needed laparotomy

[16–18]. In our study, the decision to operate on patients

with abdominal free fluid was based on frequent clinical

examination. Exploratory laparotomy was performed in

28 % of cases, of which 19 % had minimal and 9 % had

moderate abdominal free fluid. The laparotomy rate in our

study corroborates with earlier reports ranging from 19 to

54 % [16, 18]. Moreover, Cunningham et al. [17] reported

a higher rate of therapeutic laparotomy (94 %) in all

patients who underwent laparotomy, which is also similar

to our observation (91 %). Therefore, the need for lapa-

rotomy is supported by these findings. Ng et al. [13] stated

that CT scan findings were unreliable in estimating injury

severity, and recommended mandatory laparotomy for

patients with isolated free fluid on CT scan. We do not

subscribe to this philosophy, as laparotomy as a non-ther-

apeutic procedure carries a substantial risk of morbidity.

The rate of short-term complications in laparotomy varies

from 8.7 to 43 %, whereas long-term complications range

from 0 to 3.7 % cases [19, 20]. Morrison et al. [20] found

an overall short-term complication rate of 43 %, with a rate

of 20 % in those without extra-abdominal injuries. The

long-term complication rate was 1.3 %.

Moreover, the effect of delay in diagnosis on patient

outcome is inconsistent. One study [1] suggests that an 8-h

delay in diagnosis of blunt small bowel injury caused

excess morbidity. However, another study of 111 cases of

blunt small bowel perforation found that the complication

rate was significantly higher only in those patients whose

surgical procedure was delayed for at least 24 h [2]. In the

present study, 24 (19.7 %) patients underwent exploratory

laparotomy within the first 24 h, five of whom had wound

infection and one of whom had wound dehiscence. Ng

et al. [13] reported that 16 of 21 immediate laparotomies

performed were therapeutic. Two of the seven patients

initially observed also underwent laparotomy within 24 h

for missed injuries.

It is noted that the intra-abdominal injury is significantly

associated with certain injury patterns. Abdominal free

fluid without solid organ injury has been associated with

pelvic fracture [16, 18]. In the present study, sustained

injury to the lumbar spine fracture (27 %), rib fracture

(14.8 %) and pelvic fracture (7.4 %) has been associated

with abdominal free fluid.

Brasel et al. [18] suggested that the presence of more

than trace amounts of free fluid without solid organ injury

in patients with blunt trauma is a strong indication for

celiotomy. Other investigators have recommended serial

physical examinations as the ‘best’ method of detecting

serious intra-abdominal injury for alert patients [21, 22].

The results of our analysis also supported serial abdominal

examination, which was successful in averting laparotomy

in 87 patients (72 %). In the present study, intra-operative

findings revealed mesenteric injury with ischemic or con-

tusion of small bowel in 12 patients, five of whom had

moderate and seven of whom had trace amounts of

abdominal free fluid. Our findings are consistent with an

earlier study showing that CT findings of thickened bowel

wall, together with mesenteric bleeding had a higher pos-

sibility of detection of major injuries during laparotomy

[23].

Several studies have investigated the risk factors asso-

ciated with increased intra-abdominal injuries. A signifi-

cant association has been observed between the presence of

seat belt sign and increased number of injuries requiring

laparotomy [21]. Chandler et al. [24] demonstrated an

association between intra-abdominal injuries with seatbelt

sign and therapeutic laparotomy. In contrast, Livingston

et al. [25] found no correlation between the presence of

seat belt sign and injury requiring treatment in a multi-

centre study.

On multivariate analysis, mechanism of injury (pedes-

trian injury), age, and presence of seat belt sign were sig-

nificantly associated with therapeutic laparotomy in our

study. These findings are consistent with earlier studies [21,

22]. However, unlike in other reports [13], associated

injuries such as pelvic fracture and lumbar spine fracture

(except for seat belt sign) were not found to increase the

possibility of bowel injury. In addition, bowel-related

complications were due to delayed surgery ([24 h), which

is acceptable in such contaminated bowel surgery (three

wound infections out of seven laparotomies and one leak

out of 11 colonic injuries) in our study. We believe that the

period of 48 h observation for those with benign abdominal

examination can decrease the requirement of non-thera-

peutic laparotomy and its associated complications.

In conclusion, the findings of CT scans were inaccurate

for prediction of bowel injury or need for surgery. However,

the correlation between CT scan finding and clinical course

is important for optimal diagnosis of bowel and mesenteric

injuries. On the basis of our findings, we do not recommend

immediate celiotomy in abdominal injury patients. More-

over, alert patients should be followed-up with serial phys-

ical examinations. For patients whose physical examinations

are unreliable or equivocal, laparoscopy or laparotomy is a

reasonable method of management.

Acknowledgments The authors thank all the staff of trauma surgery

for their kind cooperation. This study has been approved by the

Medical Research Center, Hamad General Hospital (IRB# 10076/10).

The authors have no financial issues to disclose and no conflicts of

interest. All authors read and approved the manuscript.

1414 World J Surg (2014) 38:1411–1415

123

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