Small bowel obstruction (SBO) calls for surgical emergency most common in the elderly population and its mortality (10%) and morbidity rates are also high. SBOs are generally the result of scar tissue, hernia or cancer. It is more common in developing countries accounting for 1-8 death per 1,00,000 population per year. SBO is the cause for 50% emergency laparotomies every year in the UK and over 3,00,000 admissions in the USA. In the US, most admissions for SBO are due to the effect of prior surgeries. Surgery for SBO primarily depends on the cause of the obstruction-some are treated without operation and others are operated for intestinal ischemia. While SBO in developed countries is due to intra-abdominal adhesions (in 75%b cases) followed by hernia, Crohn’s disease, malignancy and volvulus SBO in low- and middle-income countries is due to hernia (30-40%), adhesions (about 30%) and tuberculosis (10%) apart from Crohn’s disease, volvulus and parasitic infections. Bowel obstruction might be partial or complete where partial bowel obstruction allows some liquid and gas to pass through the point of obstruction but complete obstruction restricts any passage of bowel content.
Almost 10-12% patients above the age of 65 reporting abdominal pain at the emergency department are confirmed with small bowel obstruction and, emergency surgeries in elderly population is associated with high mortality and morbidity compared to elective operations. Those patients treated in a non-operate manner mostly have zero intake via mouth for days together while patients after surgery suffer from varying degrees of postoperative ileus. Such restrictions (going without food intake via mouth) can have debilitating effects on the patient who is already a high-risk candidate for malnutrition risk. Malnutrition is bad and even more profound in those with acute intestinal failure due to SBO. It would be helpful in assessing the prevalence rates of malnutrition and management options.
Nutritional Balance in Patients with SBO
The study included all UK hospitals undertaking emergency general surgery and adults over 18 suspected for SBO excluding those who were diagnosed with non-mechanical SBO, left colonic obstruction causing SBO or those managed with palliative intent for admission were not included in the analysis. Various details were noted such as period spent without consuming anything via mouth prior to admission in the hospital, body mass index, interval between last enteral intake and re-introduction of eating via mouth and nutritional supportive interventions were recorded. Nutritional Risk Index (NRI) was noted down using ideal body weight, current weight and admission albumin and patients were put into three different groups depending on NRI values-low risk (NRI >97.5), moderate risk (NRI 83.5-97.5) and severe risk (NRI<83.5).
On execution of all conditions for inclusion in the study, a total of 2604 patients from 131 hospitals were included in the study. Here again patients were excluded based on few criteria (such as end-of-life care and not meeting study criteria) finally leaving the study with 2069 patients for analysis. Almost 30% patients were taken to surgery within 24 hours of admission, 22% were operated after being tried on non-operative procedures and 47.9% were treated in a non-operative fashion. All the patients had three things in common-all of them had a mean average age of 67, a small number of them were females and postoperative adhesions were the common cause of SBO. Results showed that 81.6% patients were assessed for malnutrition either by gauging with a screening tool or clinical judgement. 84.6% were assessed for malnutrition in comparison to 78.6% in the non-operative group. Among those whose NRI scores identified them as having moderate risk 36.4% got the help of a dietitian and the average time of review was 6.4 days. Those whose NRI scores showed severe risk had 55.9% of them reviewed by a dietitian and the average time for review was 4.5 days. Those in the low risk group had only 1 review every week with the dietitian.
The nutritional interventions taken also depended on the NRI value. Among those in the low risk group only 30.3% patients received a nutritional intervention, 40.7% of them in moderate risk group got nutritional interventions and 62.7% in the severe risk group received the same. Higher and moderate NRI values indicated higher risk of malnutrition. Also, these were the ones who had severe or moderate risk of malnutrition at 4.2 and 2.4 times higher unadjusted risk of in-hospital mortality versus those in the low risk group. Severe and moderate risk patients were likelier to develop deliriums, infections and also had higher chances of re-operations. On a comparison, those patients in severe risk group who underwent a surgery were at a lower risk of hazard compared to those who were treated in a non-operative manner. The minimum time taken to initiate food intake orally was at least 1 week where operative treatment procedures usually took more time for oral feeding compared to non-operative ones.
Almost one third of patients with acute SBO are at risk of malnutrition and this risk is associated with poorer outcomes. There are also chances that the patient is judged to be well-nourished while being admitted to the hospital but might later go on to develop malnutrition. The same happened in this study where 28% patients in the low-risk group were judged to have malnutrition and 12% ended up receiving parenteral nutrition. It is recommended to go for oral nutritional supplements when the patient is at risk of malnutrition and parenteral nutrition when there is no oral intake for more than 5 days. The risk here is that malnutrition might be detected at early stages of SBO but it is not readily correctable through conventional enteral interventions due to compromise of intestinal function. Gastrointestinal failure prevents nutritional improvement and absorption which prevents adequate calorie intake. This shows that SBO is highly prevalent in the SBO patients, even diagnosis rates are higher but preventive methods and nutritive programs are not much in place to treat it.
Malnutrition, nutritional interventions and clinical outcomes of patients with acute small bowel obstruction: https://bmjopen.bmj.com/content/9/7/e029235
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