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 Table of Contents  
Year : 2020  |  Volume : 10  |  Issue : 3  |  Page : 134-138

Prebiotic prophylaxis of abdominal bloating in mechanically ventilated patients fed through nasogastric tubes: A randomised clinical trial

1 Department of Public Health, School of Medicine, Dezful University of Medical Sciences, Dezful, Iran
2 Faculty of Nursing and Midwifery, Non-Communicable Diseases Research Center, Sabzevar University of Medical Sciences, Sabzevar, Iran
3 Department of Epidemiology, School of Public Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
4 Social Determinants of Health Research Center, Lorestan University of Medical Sciences, Khorramabad, Iran

Date of Submission29-May-2020
Date of Decision16-Aug-2020
Date of Acceptance27-Aug-2020
Date of Web Publication22-Sep-2020

Correspondence Address:
Azam Zarghi
MSc in Nursing Care, Faculty of Nursing and Midwifery, Non-Communicable Diseases Research Center, Sabzevar University of Medical Sciences, Sabzevar
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/AIHB.AIHB_50_20

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Objective: Enteral nutrition is the first choice of nutritional support of patients undergoing mechanical ventilation. Gastrointestinal disorders, especially abdominal bloating, are commonly seen in this group of patients. Given the prevalence of bloating and its perceived severity, the lack of an effective method for the control or treatment of this problem during mechanical ventilation is urgently felt. Materials and Methods: This double-blind, randomised, controlled clinical trial was conducted on 60 mechanically ventilated patients divided in two groups (n = 30). The study group received fenugreek seed (FS) powder by gavage twice a day besides the routine care. The control group only received routine care. Abdominal bloating, consisting of abdominal pain intensity, abdominal circumference, vomiting, frequency deification, bowel sounds and gastric residual volume, was measured at the baseline and every day for 5 days. Results: By the end of study, abdominal bloating decreased significantly in the study group compared to controls (P < 0.05). Conclusion: Given that even a slight reduction in symptoms can produce positive public health consequences, daily diet with FSs is recommended for critically ill patients.

Keywords: Abdominal bloating, fenugreek seeds and gut bacteria, prebiotic

How to cite this article:
Khazaei Z, Moayed L, Sharifnia G, Goodarzi E, Zarghi A. Prebiotic prophylaxis of abdominal bloating in mechanically ventilated patients fed through nasogastric tubes: A randomised clinical trial. Adv Hum Biol 2020;10:134-8

How to cite this URL:
Khazaei Z, Moayed L, Sharifnia G, Goodarzi E, Zarghi A. Prebiotic prophylaxis of abdominal bloating in mechanically ventilated patients fed through nasogastric tubes: A randomised clinical trial. Adv Hum Biol [serial online] 2020 [cited 2021 Jun 19];10:134-8. Available from: https://www.aihbonline.com/text.asp?2020/10/3/134/295834

  Introduction Top

Mechanically ventilated patients may face a number of nutritional challenges.[1] Enteral nutrition is often complicated by gastrointestinal (GI) disorders, such as accumulation of gas or bloating.[2] Bloating and distension have been reported in 20%–30% of the general population, with around half of patients in critical care suffering from these symptoms, which may influence their health status.[3] Even slight changes in abdominal contents can lead to the dysfunction of several organs and raise patient mortality rates.[4]

Gut microbiota represent a wide variety of bacterial species, which can exert an enormous effect on diverse physiological function.[5] Gut microbiota can regulate the initiation and propagation of migrating motor microbial activities.[6] During excess caloric intake or cachexia periods, microbial activities are significantly altered.[7]

Prebiotics are food compounds that can alter the population of beneficial microorganisms and stimulate advantageous activity or inhibit the growth of detrimental and potentially pathogenic microbes in the gut.[8] Prebiotics are fermented into important nutrients such as acids, short-chain fatty, butyrate, vitamins and amino acids.[7]

Clinical evaluation of abdominal pain is largely subjective, and in cases when the patient unable to describe disease history, the abdominal examination can be equivocal. As a result, the outcomes of treatment are frequently unsatisfactory.[8] However, there are some drugs used for the treatment of bloating, but evidence that support their efficacy is limited.[9],[10],[11]

The body of exiting data indicates that gut microbiota communicates regulate anxiety, mood, cognition and pain.[12],[13] It is important to note that probiotics carry the inherent risk of iatrogenic infection in critically ill patients while prebiotic growth inhabits gut microbial communities.[14]

Fenugreek (Trigonella foenum-graecum) is an annual aromatic herb of the legume family. Fenugreek seeds (FSs (contain oligosaccharides or bifidogenic factor, which is a rich source of antioxidant and antibacterial properties as well as carbohydrates that raise the nitric oxide levels.[15]

Kooshki et al. (2018) measured the antimicrobial activity of boiling water extracts of FSs against Escherichia coli, Proteus vulgaris, Staphylococcus aureus, Candida albicans, Staphylococcus epidermidis and Staphylococcus.[14] Ibrahim revealed that FSs could be used to control stomach gases through adsorption or complex formation.[16]

Olsen and Gudmand-Hoyer studied galactooligosaccharide in 44 irritable bowel syndrome patients, which were divided into three groups. All three groups received 7 g/day placebo, 3.5 g/day Glasgow Outcome Score (GOS) and 3.5 g/day placebo or 7 g/d GOS for 6 weeks with the results indicating significantly improvement in flatulence, bloating and the composite score of symptoms, as well as subjective global assessment. It also increased the proportion of bifidobacteria in faecal samples.[17]

Evaluation of abdominal pain in critically ill patients is particularly challenging for nurses and researchers in the field.[18] According to evidence regarding the therapeutic effects of FSs on some abdominal disorders, the purpose of this study is to investigate the effect of prebiotic prophylaxis of abdominal bloating in mechanically ventilated patients fed through nasogastric tubes.

  Materials and Methods Top

This clinical randomised trial was conducted on 60 mechanically ventilated patients admitted to 2 intensive care units (ICUs) in Dr. Shahid Beheshti and the Mohammad Vasei Hospitals in Sabzevar, Iran, from April 2015 to June 2016. The study was in compliance with code of ethics (registration no. IR.MEDSAB.REC.1394.128). The patients were randomised into two groups: Group 1 (n = 30) and Group 2 (n = 30).

The objectives and risk of the research were explained to participants, and an informed consent from was obtained from patients or their legal guardians. Exclusion criteria included any changes in the patient's condition that disrupted the oral intake of food, digestive tract surgery during the current admission, intestinal ischaemia, septic patients and bleeding disorders or internalised normalised ratio >2.

Medical history, physical examination, Acute Physiology and Chronic Health Evaluation II (APACHE II) score and primary diagnosis of patients were recorded. Using the random number table, patients were randomly assigned to control or study groups and the same patient was placed in the opposite group. Sampling was continued until the desired sample size was reached [Table 1].
Table 1: Demographic characteristics of patients in the two groups

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A specific code was assigned to sample dishes. Group 1 received 3-g FS powder twice a day within 24 h of intubation and Group 2 received only the routine care for 5 days. After pouring warm soup into gavage dishes, the researcher added to into sample dishes of Group 1 12th and 18th h. Patients were force-fed under the impact of gravity within 10–15 min at a height of 12 inches above the gastric level. The patient's head was elevated >35° from the bed.

Five variables that reflect abdominal bloating including abdominal pain intensity, abdominal circumference, gastric residual volume, frequency deification and bowel sounds were considered.

Pain was evaluated using the Non-Verbal Pain Scale (NVPS). Abdominal palpation (tenderness and rigidity of the abdominal wall) can elicit a painful response. NVPS consists of five dimensions (face, activity, guarding, physiological indicators and respiratory rate). Each dimension ranges from 0 to 2 with a total pain score between 0 and 10 (no pain: 0, mild pain: 1–3, moderate pain: 4–6 and severe pain: 7–10).

Bloating is a symptom and distension is a sign. Abdominal distension indicates a discernible increase in abdominal circumference. To measure changes in abdominal circumference, the distance around the abdomen near the belly button to the plastic tape is calculated.

Diarrhoea is defined as the passage of three or more loose or liquid stools per day with a stool weight >200 − 250 g per day (or >250 mL per day). Constipation is the absence of defecation for more than 3 days.

Auscultation of bowel movements was performed for at least 5 min to the right of umbilicus in the right lower quadrant (ileocecal) at 9 in the evening. Any sound in this area may suggest an underlying partial obstruction or distension. The diagnosis is definitive if the colonic diameter is >6 cm (>9 cm for caecum) or small bowel diameter is >3 cm in X-ray or computed tomography scan.[3]

The reasons for the selection of FSs included native plant and compatibility with the patient's body in this region. FSs is a rich source of zinc, copper, manganese, calcium, iron and vitamins, nicotinic acid, alkaloids, riboflavin, carotene, thiamine, niacin, free amino acids and proteins, which are utilised as a valuable source of dietary micronutrients and contribute to the digestion and management of hyperglycaemia and hyperlipidaemia.[19]

  Results Top

A total of 116 mechanically ventilated patients were screened. During the study, 18 patients (30%) were excluded, of whom 18 (100%), 10 (55.55%) and 8 (44.44%) were in Group 2 and Group 1, respectively. Of 10 (100%) patients excluded from Group 2, 3 (27.2%) died in the first 48 h of ventilation, 3 (27.2%) were unlikely to need intubation for at least 48 h and in 4 (40%) cases, the surrogate's consent for the continuation of the study was not obtained. Of 8 (100%) patients excluded from Group 2, 4 (50%) died in the first 48 h of ventilation and 4 (50%) patients were unlikely to require ventilation for at least 48 h.

Data analysis was conducted using Stata software, version 12.0 (Stata Corp., College Station, TX, USA). Furthermore, the Kolmogorov–Smirnov test was applied to test the distribution of data and the Mann–Whitney U-tests (non-Gaussian distribution) were used for continuous variables. The mean age (P = 0.25), mean sex (P = 0.120), mean APACHE II score (P = 0.65) and cause of admission to ICU (P = 0.120) were calculated. Statistical analysis indicated that there was no significant difference between the two groups in demographic variables (P > 0.05) and they were compatible in the first study [Table 1].

The primary outcomes of the study were used to evaluate abdominal pain and abdominal circumference. The abdominal pain was analysed by the Friedman test. The two groups were not significantly different in terms of pain intensity and percentage of patients before intervention (P > 0.05). However, a significant difference with respect to the level of pain was observed between the two groups on days 4 and 5, with pain intensity rising significantly in Group 2 and plummeting in Group 1 (P < 0.05). The results of the Friedman test concerning gavage in 5 consecutive days showed a significant difference among Group 1 patients in terms of abdominal pain (P = 0.0001), but this difference was not significant in Group 2 (P = 0.484). Finally, the comparison of the two groups was significant (P = 0.0001).

At the baseline, 13.3% of the patients in Group 1 reported severe pain, but on day 5 of the study, no patient reported severe pain with 66.7% reporting no pain at all. In the meanwhile, patients in Group 2 had a higher pain level and only 10% of the patients reported the absence of any pain [Table 2] and [Table 3].
Table 2: Distribution of abdominal pain in the two groups

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Table 3: Results of Friedman test in the two groups

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According to the results, the abdominal circumference in Group 1 (1.6 cm) was significantly less than Group 2 (P = 0.028) [Table 4].
Table 4: Estimation of standardised regression coefficients in the covariance analysis model

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The secondary outcomes consisted of the mean gastric residual volume between Group 1 and Group 2 (28.06 ± 9.23 vs. 38.94 ± 9.54; P = 0.001). The average days admitted to the ICU (14.2 ± 4.7 vs. 17.6 ± 6.5; P = 0.028) and the length of stay in hospital (24.1 ± 5.6 vs. 27.4 ± 6; P = 0.041) were different between the two groups. However, the duration of MV (16.06 ± 4.81 in Group 1 vs. 20.26 ± 6.05 in Group 2; P = 0.64) was not different between the two groups. No side effects attributable to the use of FSs were observed.

  Discussion Top

Abdominal bloating is a primary cause of admission or multiple organ dysfunction syndrome, which is fairly common in critically ill patients.[3] The use of prebiotics and probiotics as nutritional and pharmacological instruments appeared to produce a positive effect on diminishing the risk of infections and the development of GI malignancies, which improved the immune system.[20] The results of this study suggest that FSs help relieve symptoms of bloating and abdominal distension (P < 0.05).

The insoluble fibres of FSs stimulate the adrenergic response, increasing the flow of catecholamine into the bowel and inducing wave-like contractions, which enhance gut transit waste rate and bowel function. The soluble fibres of FSs absorb water and produce the bulk, as a result of which the colon does not need to exert as much pressure to propel stool through colon.

Damodharan et al. reported that alginate fenugreek gum-locust matrix-enhanced viability of probiotic cells microencapsulated during 3-month storage time at 4°C and in digestive condition was efficiently tolerated.[21]

Kaur and Singh reported that using 1-g FSs along with metformin for 12 weeks in patients with type 2 diabetes significantly reduced fasting blood sugar, postprandial blood sugar level and HbA1c levels and diminished the incidence and intensity of GI symptoms compared to the control group.[22]

Ramakrishna Rao et al. reported that 2 mg of FSs stimulated bile acid secretion by about 80%. A single dose (0.5 g/g) of FSs stimulated bile acid secretion by 35% and bile flow by 44%. They showed that FSs amplified lipase enzyme activity by about 43% and chymotrypsin activity by 43% but observed a reduction in pancreatic amylase, trypsin and acid phosphatases and alkaline state.[23]

The results of above-discussed studies confirm that the use of FSs enhances the growth of beneficial gut bacteria, improving gut function and clinical outcomes.

  Conclusion Top

Bloating and distension are the most common and troublesome functional gut symptoms with a marked effect on the results of care. Given the relevance of the issue, more targeted therapeutic studies in this field are warranted.


The study was funded by the Deputy of Research at Sabzevar University of Medical Sciences. We would like to thank ICU departments for collaborating in the treatment of participants.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

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Morowitz MJ, Carlisle EM, Alverdy JC. Contributions of intestinal bacteria to nutrition and metabolism in the critically ill. Surg Clin North Am 2011;91:771-85.  Back to cited text no. 7
Gibson GR, Hutkins R, Sanders ME, Prescott SL, Reimer RA, Salminen SJ, et al. Expert consensus document: The international scientific association for probiotics and prebiotics (ISAPP) consensus statement on the definition and scope of prebiotics. Nat Rev Gastroenterol Hepatol 2017;14:491-502.  Back to cited text no. 8
Simrén M, Tack J. New treatments and therapeutic targets for IBS and other functional bowel disorders. Nat Rev Gastroenterol Hepatol 2018;15:589-605.  Back to cited text no. 9
Camilleri M, Boeckxstaens G. Dietary and pharmacological treatment of abdominal pain in IBS. Gut 2017;66:966-74.  Back to cited text no. 10
Seo AY, Kim N, Oh DH. Abdominal bloating: pathophysiology and treatment. J Neurogastroenterol Motil 2013;19:433-53.  Back to cited text no. 11
Mayer EA, Tillisch K, Gupta A. Gut/brain axis and the microbiota. J Clin Invest 2015;125:926-38.  Back to cited text no. 12
Cryan JF, Dinan TG. Mind-altering microorganisms: The impact of the gut microbiota on brain and behaviour. Nat Rev Neurosci 2012;13:701-12.  Back to cited text no. 13
Kooshki A, Khazaei Z, Zarghi A, Rad M, Tabaraie Y. Prebiotic prophylaxis of ventilator-associated pneumonia: A randomized clinical trial. Biomed Res Ther 2018;5:2287-95.  Back to cited text no. 14
Yadav UC, Baquer NZ. Pharmacological effects of Trigonella foenum-graecum L. in health and disease. Pharm Biol 2014;52:243-54.  Back to cited text no. 15
Ibrahim M. Molecular spectroscopic study of acid treated fenugreek seeds. Spectrochim Acta A Mol Biomol Spectrosc 2010;77:1034-8.  Back to cited text no. 16
Saulnier DM, Ringel Y, Heyman MB, Foster JA, Bercik P, Shulman RJ, et al. The intestinal microbiome, probiotics and prebiotics in neurogastroenterology. Gut Microbes 2013;4:17-27.  Back to cited text no. 17
Ayasrah SM. Pain among non-verbal critically Ill mechanically ventilated patients: Prevalence, correlates and predictors. J Crit Care 2019;49:14-20.  Back to cited text no. 18
Roberts K, Allen-Vercoe E, Williams S, Graham T, Cui S. Comparative study of thein vitro fermentative characteristics of fenugreek gum, white bread and bread with fenugreek gum using human faecal microbes. Bioact Carbohydr Diet Fibre 2015;5:116-24.  Back to cited text no. 19
Zentek J, Gärtner S, Tedin L, Männer K, Mader A, Vahjen W. Fenugreek seed affects intestinal microbiota and immunological variables in piglets after weaning. Br J Nutr 2013;109:859-66.  Back to cited text no. 20
Damodharan K, Palaniyandi SA, Yang SH, Suh JW. Co-encapsulation of lactic acid bacteria and prebiotic with alginate-fenugreek gum-locust bean gum matrix: Viability of encapsulated bacteria under simulated gastrointestinal condition and during storage time. Biotechnol Bioprocess Eng 2017;22:265-71.  Back to cited text no. 21
Kaur M, Singh N. Synergistic effect of metformin and fenugreek on the lipid profile of type-II diabetic patients. Int J Basic Clin Pharmacol 2019;8:1738.  Back to cited text no. 22
Ramakrishna Rao R, Platel K, Srinivasan K.In vitro influence of spices and spice-active principles on digestive enzymes of rat pancreas and small intestine. Nahrung 2003;47:408-12.  Back to cited text no. 23


  [Table 1], [Table 2], [Table 3], [Table 4]


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