A retrospective cohort study of gastrografin in the management of adhesive small bowel obstruction during pregnancy

doi:10.21203/rs.3.rs-4891661/v1

Adhesive small bowel obstruction (ASBO) during pregnancy is extremely dangerous and has not been well researched. The aim of this study was to resolve the difficulties faced in the management of ASBO during pregnancy through the dual role of the diagnosis and treatment of gastrografin. All patients with ASBO during pregnancy whose medical records were retrospectively analyzed between September 2018 and September 2023 were categorized into two groups based on the type of treatment they received: conventional and gastrografin. The two groups did not differ statistically significantly in terms of demographic information, fundamental patient features, or side effects. On the other hand, the gastrografin group outperformed the convention group in terms of improving the rate of success for conservative treatment, lowering the need for surgical procedures, reducing hospital stays, lowering medical costs, and aiding in diagnosis. Gastrografin can be safely used in the pregnant population, where its efficient therapeutic efficacy and accurate diagnostic role are key to resolving the difficulties of ASBO during pregnancy.

Health sciences/Diseases

Health sciences/Gastroenterology

Health sciences/Medical research

Pregnancy

ASBO

conventional

gastrografin

safe

One of the most prevalent acute abdominal disease during pregnancy is adhesive bowel obstruction, which is primarily caused by adhesive bands left over from prior abdominal surgery ¹. The prognosis of the mother and fetus is influenced by the severity of the condition and the time it takes to diagnose it. Improper therapy puts the mother and child at risk for major outcomes like death, intestinal resection, premature delivery, and miscarriage ².

Diagnosis and treatment are difficult due to the unique features of the pregnant population and the partial overlap between symptoms of intestinal obstruction and pregnancy reactions ^3,4. Regardless of symptoms and imaging results, a subset of academics advises receiving surgery as soon as a diagnosis is made ⁵. According to a different set of academics, stable patients can participate in conservative treatment trials with high surgical thresholds in order to reduce the danger of needless surgery ⁶. The solution to this problem thus lies in figuring out how to increase the effectiveness of conservative treatment and precisely determine when to perform surgery.

Gastrografin serves as a therapeutic and diagnostic tool and is effective in treating ASBO in the general population ^7–9. In addition to stimulating intestinal peristalsis, increasing the pressure gradient at the site of obstruction, dilution of intestinal contents, and lubrication of the intestinal tract, its therapeutic principle primarily depends on the osmotic pressure difference (1900 mOsm/L, approximately six times that of extracellular fluid) to promote the entry of intertissue fluids into the intestinal lumen to reduce intestinal wall oedema ^8,10,11. By observing the position of gastrografin on an abdominal X-ray, its diagnostic principle is to determine the location, degree, etiology, and whether the obstruction is combined with intestinal torsion and intestinal ischaemia. More importantly, it can predict whether the obstruction can be overcome by observing whether gastrografin can reach the colon within the allotted time ^8,12.

Being the biggest hospital for women and children in central China, we have seen many positive outcomes from following conventional treatment protocol. Nevertheless, it is challenging to generalize this protocol and necessitates that doctors have considerable amounts of clinical experience treating acute abdominal problems during pregnancy. Based on the foregoing background, we established a new treatment protocol for gastrografin in expectation of eliminating the clinical issues of ASBO in pregnancy and offering benefits to the pregnant community.

Study design

A retrospective examination was conducted of the medical records of pregnant patients with a preliminary diagnosis of ASBO who were admitted to Hubei Maternal and Child Health Hospital, which is associated with Tongji Medical College of Huazhong University of Science and Technology (HUST), between September 2018 and September 2023. For every patient, the following data was extracted: length of hospital stay, medical expenses, demographic data, basic patient characteristics, diagnostic and therapeutic methods, treatment outcomes, and information at the moment of fetal birth. Clinical symptoms such distension, discomfort, vomiting, and obstruction, along with imaging manifestations on an MRI, CT, X-ray, or ultrasound, were used to diagnose ASBO. Adverse drug reactions include allergies, headaches, breathing difficulties, kidney damage and so on. Fetal loss before 28 weeks was considered a miscarriage. Delivery at 28–36 weeks was considered preterm labor. After a full understanding of the risks, each patient and their family self-selected either the conventional or gastrografin treatment protocol and signed a consent form.

Inclusion and exclusion criteria

This protocol's inclusion criteria included imaging evidence, symptoms of intestinal obstruction, a history of abdominal surgery, and a confirmed pregnancy. The exclusion criteria included non-adhesive small bowel obstructions such tumors, intussusceptions, intestinal torsion, and intestinal strangulation that were either suspected or positively diagnosed during initial inspection, as well as the occurrence of peritonitis within 4 hours after admission.

Conventional treatment protocol

The patient was admitted to the hospital and immediately began getting conservative care, as shown in Figure 1. This included water and food fasting, gastrointestinal decompression, anti-infection, suppression of digestive enzymes and gastric acid, water-electrolyte balance, fetal sedation, and close observation of alterations in the fetus's and the pregnant woman's vital signs and examination indicators. To evaluate the fetal status, offer psychological counseling, and make pregnancy recommendations, an obstetrician's involvement is requested. Changes in disease are determined by a team of experienced doctors through signs, symptoms, indicators of infection, and imaging. Worsening of the disease is usually associated with increased heart rate and blood pressure, increased pain (persistent, reduced and fixed range), signs of peritonitis (pressure and rebound pain, abdominal muscle tightness), elevated white blood cells, and CT suggestive of intestinal strangulation, at which point the obstruction is considered impenetrable by conservative treatment and requires prompt surgical intervention. Abdominal pain reduction and rectal emission are typically signs of improvement; at this time, the nasogastric tube can be taken out and a liquid diet can be resumed.

Gastrografin treatment protocol

The novel regimen consists of augmenting the conventional conservative treatment with 75% gastrografin and 24-hour abdomen plain films in the following manner: After being admitted to the hospital, the patients were requested to follow the same conservative treatment and observation regimen as the traditional protocol group at first. Through a nasogastric tube, 100 ml of gastrografin was injected after more than two hours of satisfactory gastrointestinal decompression. After the injection was finished, the nasogastric tube was kept clamped for two hours before the gastrointestinal decompression was turned back on. The 24-hour observation period was then started, with abdomen plain films taken for those without anal gas and the resumption of fluid diet for those who had it. Based on the objective results shown on the X-rays, those in whom gastrografin reached the colon were determined to have an obstruction that could be overcome, and they waited for anal gas to begin resuming their diet. Otherwise, the obstruction was determined to be insurmountable, and surgical intervention was necessary as soon as possible.

Obstetric management

Pregnancy termination is not required if there are no signs of preterm labor. If there are signs of preterm labor, a bowel obstruction sugery may be performed after a cesarean section to enable exposure of the field of view.

Statistical analyses

IBM Statistical Package for the Social Sciences (IBM SPSS) version 23.0 software was used for statistical analysis. The Shapiro-Wilk test was used to determine whether the data obeyed a normal distribution, and the Levene test was used to determine the chi-squaredness. Normally distributed continuous variables were described by the mean ± standard deviation, and an independent sample t-test was performed. Non-normally distributed continuous variables were described by median (interquartile spacing), and a Mann-Whitney U test was performed. Categorical variables were described by numerical and percentage values, and chi-square, chi-square corrected, or Fisher exact tests were selected according to the number of samples in the group. P < 0.05 was considered statistically significant.

Ethics approval and consent to participate

All methods were carried out in accordance with relevant guidelines and regulations, and this study was approved by the ethics committee of our hospital (code of ethical approval for scientific research project: 2024IEC007). In addition, we confirm that informed consent was obtained from all subjects and/or their legal guardians.

From September 2018 to September 2023, at 6-36 weeks of gestation, 50 patients with a preliminary diagnosis of ASBO were seen, as indicated in Figure 2. Of these patients, forty-three fulfilled the screening requirements and could be included in the statistical analysis. Out of the seven patients who were excluded, two suffered from small bowel strangulation, one had a small intestinal mesenchymal tumor, and four developed peritonitis within four hours of admission.

Patient demographics and basic characteristics are shown in Table 1 and 2. There was no statistically significant difference observed between the two groups in terms of age, gestational week, BMI, HGB, WBC, blood pressure, fasting blood glucose, concomitant diseases, or history of past abdominal surgeries. The vast majority of ASBO cases occur in the middle and late stages of pregnancy; the early stages are uncommon. Those who had undergone two prior abdominal surgeries did not show worse outcomes in the latter course of treatment.

Table 3 demonstrate the treatment's outcomes.In terms of conservative success, length of hospital stay, and healthcare costs, there was a statistically significant difference between the two groups, with the gastrografin group clearly benefiting therapeutically (p = 0.045, p = 0.001, p = 0.003). The same result was seen even when we examined conservative and surgical patients independently across the two groups (p = 0.023, p = 0.025, p = 0.001, p = 0.023). The time for condition judgment was concentrated at 12-36 hours in the gastrografin group and dispersed at 16-155 hours in the conventional group, with the former being more efficient and objective in assisting the physician in determining whether or not the obstruction could be overcome (p = <0.001).

Table 4 displays delivery details and negative effects. Neither group experienced negative effects (adverse drug reactions, congenital malformations, or miscarriages) while receiving therapy. Regarding delivery-related factors such as fetal birth weight, gestational mode, and preterm labor, there was no statistically significant difference between the two groups.

When treating ASBO during pregnancy, the MDT team must minimize risks and maximize benefits by using well-designed protocols that take into account changes in the condition as well as the mother's and the fetus's life safety ^3,4,13. Compared to conventional treatment regimens, our gastrografin regimen has demonstrated considerable improvements in both therapeutic and diagnostic outcomes.

It is safe to provide gastrografin by nasogastric tube while pregnant. Gastrografin is a hypertonic water-soluble contrast agent with a slightly bitter taste that is made up of meglumine and sodium diatrizoate. It does not easily precipitate or coagulate and is essentially unabsorbed by the gastrointestinal tract. Its therapeutic mechanism is physical, with uncommon adverse effects, and it is easily absorbed by the peritoneum even if accidentally injected into the abdominal cavity ¹⁰. Its usage during pregnancy has not been linked to any teratogenicity or other embryotoxicity, according to studies on reproductive toxicology ⁷. We came to the conclusion that gastrografin transgestion is safe to use during pregnancy after balancing the benefits of the medication against its infrequent drawbacks. During the course of the medication in the gastrografin group, there was not a single instance of side effects reported by the patients, as well as anomalies in the development of the fetus (Table 4).

Radiological testing during pregnancy should not be completely rejected. Due to possible teratogenic consequences, X-ray exposure during pregnancy should be avoided, particularly in the early stages of pregnancy ¹⁴. Nonetheless, given the minimal risk associated with mid- and late-stage pregnancy, radiological exams can be done on expectant mothers when needed to prevent delays in the identification and management of abdominal emergencies ¹⁵. According to the ACOG guidelines for diagnostic imaging in pregnancy ¹⁶, the use of diagnostic radiological exams in clinical practice is safe during pregnancy because the exposure doses involved are well below the ones linked to fetal harm and do not increase the risk of congenital malformations, fetal growth restriction, or miscarriage. Research has demonstrated that the risk of teratogenicity is not appreciably increased by cumulative exposure to up to 50 mGy of ionizing radiation, which is comparable to five plain abdominal x-ray films or one or two abdominal CT scans ¹⁵. Radiation metrology can be minimized during the procedure by minimizing the exposure duration, frequency, and frame count, refining collimation, and employing picture holders while averting further exposures ¹⁷. Therefore, compared to the substantial risk posed by ASBO, the risk of congenital abnormalities in fetuses exposed to radiation doses below 100 mGy is insignificant ¹⁶. Thankfully, most patients manifested in the middle and late phases of pregnancy, and parents consented to radiological exams after being informed of the advantages and disadvantages. Thanks to the rapid efficacy of gastrografin, seven patients had flatus and defecation prior to the 24-hour abdomen plain film, which minimized the requirement for radiological imaging and overcomed the obstruction sooner (Figure 1).

Gastrografin demonstrated excellent therapeutic efficacy. If the obstruction can be cleared, 100 ml of gastrografin is sufficient ^8,18. Adequate gastrointestinal decompression for longer than two hours keeps gastrografin from being diluted by gastrointestinal fluids or by too much stomach contents, which could cause aspiration and vomiting. To avoid the medication being aspirated before it reaches the intestine, the nasogastric tube needs to be clamped for two hours following the dose ¹¹. The best time to take abdomen plain films following medication administration has not yet been identified ¹⁹. Testing beyond 24 hours blindly increases the danger of pregnant women and fetuses waiting for surveillance, and testing before 4 hours restricts the drug's efficacy ⁸. The majority of research has not demonstrated a discernible variation in accuracy between tests conducted at 4-6 hours and 24 hours later ^11,19. As a result, we think it is reasonable to set the abdominal plain film examination at 24 hours following gastrografin administration. With a sensitivity of 97% and specificity of 96%, the presence of gastrografin in the colon after 24 hours suggests that the obstruction is cleared up without surgical intervention ¹⁹. Our study demonstrated that the therapeutic effects of gastrografin were similar to those reported in the general population ^7,12. The gastrografin group not only significantly outperforms the conventional group in terms of conservative treatment success but also surgical interventions, hospitalization time, and healthcare expenditures (Figure 2a - c).

Gastrografin exhibits an accurate diagnostic function. The enlarged uterus pushes against the bowel, making it angled or even twisted. In late trimester of pregnancy, the head of the fetus enters the pelvis and compresses the rectum. Prolonged bed rest, elevated progesterone, and the use of antispasmodic drugs slow down intestine peristalsis. Hypercoagulability of the blood affects the hemodynamics of the mesenteric vessels. These pregnancy-specific physiologic conditions and the effects of medication may accelerate the progression of intestinal obstruction, making it more difficult for physicians to determine changes in condition ^1,3,6. A timely and accurate diagnosis is crucial because late intervention raises the risk of bowel resection, miscarriage, preterm labor, and death, while early intervention involves surgery and danger when it is not necessary. Gastrografin's capacity to successfully penetrate the site of small bowel blockage and enter the colon suggests that the obstruction has been overcome. This indicates that the drug's diagnostic role is a direct reflection of its therapeutic efficacy ¹⁹. In our gastrografin group, the specificity of the need for surgical intervention was 100%, and all were confirmed intraoperatively to be unrelieved by conservatism. Therefore, we believe that the gastrografin treatment protocolmade earlier and more precise judgments about the condition, which assisted doctors in making objective surgical decisions (Figure 2d).

This study has certain limitations. Since this is a retrospective cohort study, there may be statistical bias due to the small number of patients.

Gastrografin can be safely used in the pregnant population, and its highly effective treatment and accurate diagnostic role are key to addressing the difficulties of ASBO in pregnancy. It also has the advantage of increasing conservative success rates, shortening hospitalizations, and reducing healthcare costs. This strategy warrants further multicenter prospective trials in larger cohort studies.

Acknowledgements

We are grateful to our obstetricians for their participation and help.

Funding

No funding was received for this study.

Data availability

The datasets for the current study are available from the corresponding author upon reasonable request.

Competing interests

The authors declare that they have no competing interests.

Author Contributions

Qiu Li and Xiaojun He designed the study, analysed and interpreted the data, and drafted the manuscript. Huihua Lou contributed to the manuscript review, critical appraisal, and expert advice. Rong Peng, Xiaosong Zheng, and Chenwei Wang participated in this study. All authors reviewed and approved the final draft of the manuscript.

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Table 1. Demographics of pregnant women with ASBO.

	Convention group	Gastrografin group	p value
Number of patients	22	21
Admissions with at least 1 comorbidity, n (%)	8（36.36%）	6（28.57%）	0.586
Diagnosis for abdominal surgery in the past
Cesarean section	10	11
Hysteromyoma	5	3
Ovarian cysts	3	5
Ectopic pregnancy	2	1
Appendicitis	2	2
Cholecystitis	1	1
Hernias	1	0
Admissions with history of at least 2 abdominal surgeries in the past, n (%)	2（9.09%）	2（9.52%）	1

Table 2. Basic admission profile of pregnant women with ASBO. BMI=Body mass index，HGB=Hemoglobin，WBC=white blood cell count，SBP=Systolic blood pressure，FBG=Fasting blood glucose

	Convention group	Gastrografin group	p value
Age (years)	30.27±2.68	29.19±2.84	0.205
Week of pregnancy	27.55±8.53	27.9±6.71	0.879
BMI	23.28±1.72	23.51±1.61	0.662
HGB	106.77±9.08	104.29±9.83	0.394
WBC	11.61±1.18	11.2±0.93	0.217
SBP	123.09±9.79	124.76±15.56	0.674
FBG	4.55±0.54	4.74±0.68	0.308

Table 3. Patient outcomes. ^amedian (interquartile range)，^bmean±standard deviation，^cn (%)

	Convention group	Gastrografin group	p value
Length of stay (LOS)
Overall LOS^a	9（7-14.25）	6（6-7）	0.001***
Conservation LOS^b	7.31±1.38	6.26±0.73	0.023*
Surgery LOS^a	15（13-16.5）	11.5（11-12）	0.025*
Surgical outcomes
Need for surgery^c	9（40.91%）	2（9.52%）	0.045*
Laparoscopic surgery^c	3（33.33%）	2（100%）	0.182
Intestinal resection^c	4（44.44%）	0（0%）	0.491
Medical costs
Overall medical cost^a	9.55（8.43-24.18）	5.50（5.15-6.7）	0.003**
Conservation cost^b	8.12±1.75	5.73±0.87	＜0.001***
Surgery cost^a	25.60（22.5-46.55）	21.55（20.06-22.5）	0.023*
Time of judgement for conservative treatment outcomes（hours）^b	75.23±8.47	29.29±0.40	＜0.001***

Table 4. Delivery details and negative effects. ^an (%)，^bmedian (interquartile range)

	Convention group	Gastrografin group	p value
Adverse drug reaction^a	0	0
Congenital malformations^a	0	0
Miscarriage^a	0	0
Preterm labour^a	4（18.18%）	2（9.52%）	0.664
Cesarean section^a	6（27.27%）	8（38.09%）	0.449
Foetal birth weight^b	3118（2838-3196）	3152（3098-3213）	0.423

No competing interests reported.

A retrospective cohort study of gastrografin in the management of adhesive small bowel obstruction during pregnancy

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Abstract

Figures

Introduction

Materials and methods

Results

Discussion

Conclusion

Declarations

References

Tables

Additional Declarations

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