Roberto N. Gonzales Jr, MD.

Catherine Co MD.

Edgardo Penserga MD.

 Reynaldo Joson MD.

Department of Surgery

Ospital ng Maynila Medical Center

Reprint requests:  Roberto N. Gonzales Jr. MD, Department of Surgery, Ospital ng Maynila Medical Center, Quirino Ave, Malate, Manila, Philippines

Email: ommcsurgery@yahoogroups.com

water-soluble contrast study in adhesive small bowel obstruction

Abstract

BACKGROUND:  Oral water-soluble contrast agent has been used to differentiate partial from complete small bowel obstruction. It may also have a therapeutic effect and predict the need for early surgery in adhesive intestinal obstruction. OBJECTIVE: To compare the mean hours needed to arrive at an operative decision using oral contrast agent versus clinical examination among patients with adhesive small bowel obstruction. MATERIALS AND METHODS:

All patients were diagnosed with adhesive intestinal obstruction and were randomized into two groups, a Control group and a Contrast group. Five patients in the control group and five in contrast group were included in the study. Patients in the Contrast group will received 60 ml water-soluble contrast agent  mixed with 40 ml of distilled water after two hours of NGT decompression  following admission. Those in whom the contrast medium reached the colon in 24 hours will be  considered to have partial intestinal obstruction and will be fed orally. All patients in whom water-soluble contrast agent  failed to empty into the ceacum within 24 hours of administration,will be  operated. Results : Oral contrast study is safe and can facilitate the prediction of the necessity of early operative intervention compared to a plain radiograph. Also it was seen that it was sufficient to study the patients for 24 hours after administration of oral contrast.  Conclusion : Oral contrast agent helps in the management of patients with adhesive intestinal obstruction.

INTRODUCTION

Postoperative adhesions account for about 50% of patients presenting with small bowel obstruction.  Conservative management is the norm in these patients unless there are clear cut signs of bowel ischemia. However, there are several pitfalls in such conservative management. Firstly, it is not prudent to wait for these signs as this leads to many unnecessary bowel resections and increased morbidity. Secondly, many patients continue to remain obstructed for several days even without these signs. Surgery delayed beyond 48 hours in such patients entails significant complications.

To overcome these difficulties, early and accurate prediction as to whether an episode of adhesive small bowel obstruction would resolve spontaneously or not is essential. Hyperosmolar water-soluble contrast studies  have been suggested as an objective method to decide on the line of management in individual patients. Furthermore, being hyperosmolar, they have been said to relieve partial obstruction.

To date, however, there are no prospective clinical trial done in our setting to support this suggestion.

The aim of this study was:

To compare the mean hours needed to arrive at an operative decision using oral contrast agent versus clinical examination among patients with adhesive small bowel obstruction.

Hypothesis of the Study

Ho:  Hcr = Hce:  There is no significant difference between the mean hours needed to arrive at an operative decision using oral contrast agents and clinical examination.

H1:  Hcr ≠ Hce:  There is a significant difference between the mean hours needed to arrive at an operative decision using oral contrast agents and clinical examination.

MATERIALS AND METHODS

In this randomized (patients were alternately assigned either "Group A or Group B"), controlled, prospective study, patients admitted with a diagnosis of adhesive small bowel obstruction in the Department of  Surgery in this Institution  from January, 2008 to August, 2008 will be  studied.

Inclusion criteria:

1. All patients above 18 years of age who had been admitted with a diagnosis of adhesive small bowel obstruction.
2. All such patients who had a history of previous abdominal surgery.

Exclusion criteria:

1. Evidence of peritonitis on admission or within 24 hours of admission.
2. Patient with palpable intraabdominal mass.
3. Patient with history of previous surgery for intraabdominal malignancy.
4. Patients who history of hypersensitivity or allergy.

Diagnosis was established based on the presence of:

• History of previous surgery
• Abdominal distention
• Vomiting
• Obstipation

Diagnosis was confirmed by findings of:

• Distended small bowel loops and/or Multiple air fluid levels on plain abdominal X-rays.

After assigning patients to Group A or Group B alternately, I.V. fluid replacement will be initiated and nasogastric aspiration carried out for 2 hours. In group A, a radiographic contrast study will be conducted. Sixty milliliters of WSCA (0.1 gm of sodium diatrazoate and 0.66 gm meglumine diatrazoate per ml) mixed with 40 ml distilled water will be administered via a nasogastric tube which will be subsequently clamped for 1 hours. Serial abdominal X-rays were taken at 6, 12, 18 and 24 hours after WSCA instillation. In patients in whom the radiographic contrast will be seen to have reached the caecum, the nasogastric tube will be taken out, oral feed will be started and all subsequent study will be cancelled. All patients in whom the radiographic contrast do not reach the caecum within 24 hours will undergo operation.

In group B, no radiographic contrast study will be carried out. All these patients will be observed clinically and will be operated as and when deemed necessary depending on increasing signs of obstruction or no response to conservative treatment (this was the protocol followed in this department prior to this study in all cases of adhesive small bowel obstruction).

            Passage of flatus and stool accompanied by resolution of abdominal pain            and distention suggest response to conservative treatment.
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Outcome measures:

We are going to measure the number of hours from the time of admission to the time of decision whether to operate or not.

Computation for Sample size

<!--[if !supportLists]-->n  <!--[endif]-->2007 census – 49 cases

<!--[if !supportLists]-->n  <!--[endif]-->Average monthly admission – 4

<!--[if !supportLists]-->n  <!--[endif]--> Computed Sample size for the study

            - 10 cases

<!--[if !supportLists]-->A.    <!--[endif]-->No conray

<!--[if !supportLists]-->B.     <!--[endif]-->Conray

α < 0.05, Reject H0

t = -28.98

α = 2.58531 ^-05

Therefore, reject H0

Results : Oral contrast study is safe and can facilitate the prediction of the necessity of early operative intervention compared to a plain radiograph. Also it was seen that it was sufficient to study the patients for 24 hours after administration of oral contrast .

 Conclusion : Oral contrast agent helps in the management of patients with adhesive intestinal obstruction.

Referrences:

Water-soluble contrast medium (gastrografin) value in adhesive small intestine obstruction (ASIO): a prospective, randomized, controlled, clinical trial.
Di Saverio S, Catena F, Ansaloni L, Gavioli M, Valentino M, Pinna AD.
Emergency Surgery Unit, Department of Surgery, S. Orsola Malpighi University Hospital, University of Bologna, Via Massarenti 9, Bologna, Italy. salo75@inwind.it

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