|Year : 2017 | Volume
| Issue : 4 | Page : 217-223
Predictive factors of management outcome in adult patients with mechanical intestinal obstruction
Adebambo Olalekan Bankole, Adedapo Olumide Osinowo, Adedoyin Adekunle Adesanya
Department of Surgery, General Surgery Unit, College of Medicine, Lagos University Teaching Hospital, University of Lagos, Lagos, Nigeria
|Date of Web Publication||18-Jan-2018|
Dr. Adebambo Olalekan Bankole
Department of Surgery, General Surgery Unit, College of Medicine, Lagos University Teaching Hospital, University of Lagos, Lagos
Source of Support: None, Conflict of Interest: None
Background: Mechanical intestinal obstruction (MIO) is a common and potentially fatal surgical emergency, which constitutes about 20% of all admissions to the surgical emergency departments. Objective: To determine the predictive factors of morbidity and mortality in patients undergoing treatment for MIO at our tertiary hospital. Patients and Methods: This was a prospective study of consecutive patients, 18 years and above, that presented with features of MIO during a 1-year period (May 2014 to April 2015). Each patient had resuscitation, comprehensive clinical evaluation, appropriate investigations and definitive treatment. The data were analysed using SPSS version 22. Results: One hundred and five patients were studied. The age range was 18–86 years with a mean (standard deviation) of 45.6 (14.8) years. There were 54 males with a male to female ratio of 1.1–1. The common causes of MIO were post-operative adhesion (48.6%), tumour (25.7%), external hernia (15.2%) and volvulus (5.7%). Eighty-four patients (80%) had operative intervention while 21 patients (20%) had conservative management. Univariate analysis showed that dehydration, tachycardia (>90 bpm), pyrexia, abnormal levels of potassium, urea and creatinine, leucocytosis, American Society of Anesthesiologists (ASA) status >IIIE, bowel resection, intraoperative blood loss >500 ml and duration of surgery >2 h were significant predictors of mortality (P < 0.05). Multivariate analysis showed that elevated serum urea at hospital presentation and ASA status greater than IIIE were the independent predictors of mortality, but none of the factors could independently predict morbidity. The most common post-operative complication and cause of death were wound infection (29.6%) and sepsis (66.7%). The mortality rate was 14.3%. Conclusion: The most common cause of MIO was post-operative adhesion. Elevated serum urea and ASA status greater than IIIE were the independent predictors of mortality.
Keywords: Adhesive small bowel obstruction, morbidity rate of intestinal obstruction, predictive factors of intestinal obstruction
|How to cite this article:|
Bankole AO, Osinowo AO, Adesanya AA. Predictive factors of management outcome in adult patients with mechanical intestinal obstruction. Niger Postgrad Med J 2017;24:217-23
|How to cite this URL:|
Bankole AO, Osinowo AO, Adesanya AA. Predictive factors of management outcome in adult patients with mechanical intestinal obstruction. Niger Postgrad Med J [serial online] 2017 [cited 2018 Oct 19];24:217-23. Available from: http://www.npmj.org/text.asp?2017/24/4/217/223461
| Introduction|| |
Intestinal obstruction is a condition in which there is stoppage or impediment to the antegrade progression or onward passage of intestinal gas, digestive juices and food. It is a common and potentially fatal surgical emergency, which constitutes about 20% of all admissions to the emergency rooms. The aetiological factors of mechanical intestinal obstruction (MIO) vary according to the level of socioeconomic development of countries.,, In the developed countries, adhesive obstruction is by far the most common cause of MIO, reflecting the increasing number of abdominal surgical procedures being performed, whereas hitherto, inguinal hernia was the leading cause in developing countries.,,,, Morbidity and mortality are usually due to delay in presentation, diagnosis and intervention.
The mortality rates in developed countries of Europe and America have reduced from 60% in the early1900s to as low as 4% in the 1980s. In the West African subregion, however, mortality rates from various studies ranged from 6 to 13%.,,,, It is therefore necessary to regularly assess the role of factors such as delayed presentation, patient's age, cause of obstruction, site of obstruction, bowel viability, length of bowel resected, presence of shock, total white cell count (WBC); blood urea, creatinine and potassium; pre-operative indices such as pulse rate and body temperature; that may predict the outcome of MIO.,,
It is important to identify these predictive factors, so they can be prevented or their effects ameliorated to thereby reduce morbidity and mortality of MIO in our subregion. The aims of this study were to determine the predictive factors of morbidity and mortality among patients undergoing treatment for MIO in our tertiary health facility.
| Patients and Methods|| |
This prospective study was performed at the Lagos University Teaching Hospital, during a 1 year period from May 1, 2014, to April 30, 2015. Ethics approval was obtained from our institutional ethics committee for the study on March 25, 2014, with protocol number ADM/DCST/HREC/1742.
All consecutive patients aged 18 years and above with clinical features of MIO who presented to the surgical emergency room were recruited for the study. Each patient was adequately resuscitated followed by comprehensive clinical evaluation and performance of relevant investigations.
Patients with clinical diagnosis of adhesive small bowel obstruction following previous laparotomy who had obstruction confirmed by plain abdominal radiographs were initially managed conservatively with nasogastric suctioning, intravenous fluids and antibiotics. They underwent serial clinical and radiological evaluations to determine resolution of the obstruction. Those who showed evidence of resolution of obstruction were then commenced on graded oral intake. However, patients with failed conservative treatment were offered operative intervention. Patients that were clinically diagnosed as having MIO caused by tumour, external or internal hernias, volvulus and intussusception had operative intervention after adequate resuscitation.
The following variables were obtained from each patient: demographic data, duration of symptoms before presentation (DSBP), presence or absence of co-morbidity, surgical intervention time (SIT), haematological and biochemical parameters, American Society of Anesthesiologists (ASA) score, method of treatment (whether conservative or operative), the nature of obstruction, level of obstruction, bowel viability, bowel resection, length of bowel resected and type of bowel resected, volume of intraoperative blood loss and duration of anaesthesia and surgery (DAS). The effects of the aforementioned variables on morbidity and mortality were also determined.
For the purpose of this study, the presence of comorbidity was defined as the existence of another medical disease that is independent of MIO. Tachycardia was defined as pulse rate >90 beats per minute at hospital admission. Pyrexia was defined as elevated body temperature, at presentation, >37.4°C. Hyperkalaemia, elevated urea and creatinine were defined as the laboratory values, at presentation, greater than the upper limit of the respective reference ranges. Leucocytosis was defined as elevated WBC >11,000/mm 3 at presentation. DSBP was taken as the time interval between the onset of a symptom or group of symptoms and the arrival of the patient at the hospital. SIT was defined as the interval between arrival in hospital and operative intervention. The case fatality rate (CFR) was defined, in percentage, as the proportion of deaths occurring in patients with MIO within the group of patients with MIO. ASA scores were ASA I, ASA II, ASA III, ASA IV and ASA V. ASA I was a normal healthy patient; ASA II was a patient with mild systemic disease; ASA III was a patient with severe systemic disease while ASA IV was a patient with severe systemic disease that is a constant threat to life. Morbidity was regarded as post-operative complications or continued ill health beyond 14 days of admission in cases without mortality. Exclusion criteria included patients with severe co-morbid diseases such as diabetic coma and heart failure and those with paralytic ileus.
Statistical analysis was performed using SPSS Version 22.0 (SPSS Inc., Chicago, IL, USA) to calculate percentages, means and standard deviation for quantitative variables and frequencies for categorical data. Univariate analysis was performed to test relationship between independent and dependent variables. Differences were considered as statistically significant at P ≤ 0.05. Multivariate analysis was carried out to determine the effect of individual statistically significant predictive factors on both morbidity and mortality.
| Results|| |
A total of 105 out of 115 patients who presented to the hospital with MIO were recruited for this study. The age range of recruited patients was 18–86 years with a mean age of 45.6 ± 14.8 years. The age range 41–50 years had the highest number of patients presenting with MIO. There were 54 (51.4%) males and 51 (48.6%) females, resulting in a male to female ratio of 1.1: 1. The mean age of the survivors was 46.0 ± 15.0 years while that of non-survivors was 43.3 ± 13.9 years (P = 0.51).
The patients had multiple symptoms and signs but the most common were abdominal pain; 104 patients (99%), absolute constipation; 102 patients (97.1%) and abdominal distension; 92 patients (87.6%). The mean DSBP was 56.3 ± 35.7 h. The mean duration of symptoms for survivors and non-survivors were 54.8 ± 35.8 h and 65.5 ± 34.6 h, respectively (P = 0.28). Seventy-two (68.6%) patients presented more than 24 h after onset of symptoms while 33 (31.4%) patients presented within 24 h of onset of symptom. Eighty-four patients (80%) had operative intervention while 21 patients (20%) had conservative management. Thirty cases (30) were initially managed conservatively, out of which one death was recorded and 9 cases were converted to operative treatment, resulting in a failure rate of 33.3% for conservative treatment. The causes of MIO included adhesions 48.5% (51 cases), colorectal tumours 25.7% (27 cases), external hernias 15.2% (16 cases,) volvulus 5.7% (6 cases), intussusception 1.9% (2 cases), granulomatous infection 1.9% (2 cases) and internal hernia 0.9% (1 case).
Morbidity was recorded in 57 patients (54.3%); 56 patients had one or more post-operative complications each hence a post-operative complication rate of 66.7% (56/84) and one patient (4.8%) managed conservatively had pulmonary embolism. The common post-operative complications were surgical site infection, electrolyte imbalance and enterocutaneous fistula occurring in 33, 12 and 7 cases, respectively. Post-operative mortality was recorded in 15 patients (14.3%), with sepsis accounting for 10 (66.7%) deaths, electrolyte imbalances and pulmonary embolism with 2 deaths each and 1 patient died due to complications arising from severe malnutrition.
Predictors of morbidity
Univariate analysis [Table 1] showed that patients who presented with dehydration, tachycardia, pyrexia, hyperkalaemia, hypokalaemia, elevated serum urea and creatinine had significantly higher morbidity (P< 0.05). Furthermore, patients with high ASA scores (scores IVE and VE) and those that required bowel resection had significantly higher morbidity rates than patients with lower ASA scores and no bowel resection (P< 0.05) [Table 2].
Predictors of mortality
[Table 3] revealed that dehydration (P = 0.02) and tachycardia (P = 0.00) at presentation were found to be significantly associated with mortality. The CFR in patients with no dehydration and those with dehydration were 4.9% (2/41) and 20% (13/64), respectively [Table 3]. In addition, the mean pulse rate of survivors and non-survivors were 96.1 ± 9.7 bpm and 130.6 ± 18.5 bpm, respectively, P = 0.00. Furthermore, univariate analyses showed that pyrexia and leucocytosis were significant predictive factors for mortality (P< 0.05). The CFR among patients with normal temperature was 5.8% (4/69) while that of patients with pyrexia was 30.6% (11/36), P = 0.00, [Table 3]. The mean WBC was 10.4 × 106 ± 4.6 cells/mm 3. CFR of patients with normal WBC/neutrophil count and those with leucocytosis were 8.6% (6/70) and 25.7% (9/35), respectively, P = 0.02, [Table 3].
[Table 3] revealed that hypokalaemia/hyperkalaemia is a significant predictor of mortality as the CFR among patients with normal serum potassium and those with hypokalaemia/hyperkalaemia were 5.5% (3/55) and 24.0% (12/50), respectively (P = 0.01). Similarly, high serum urea and creatinine above the reference ranges were significantly associated with mortality, P = 0.00 and 0.0003, respectively. The CFR in patients with serum urea and creatinine above the reference ranges was 47.6% (10/21) and 28.9% (13/45), respectively, while the corresponding values for patients with normal serum levels of urea and creatinine were 6.0% (5/84) and 3.3% (2/60), respectively [Table 3].
High ASA scores were significantly associated with mortality, as ASA scores of IIE and IIIE had CFR of 3.5% (2/57) while with higher ASA scores (ASA IVE and VE) had CFR of 44.4% (12/27), P = 0.000 [Table 4]. Likewise, the DAS was significantly associated with mortality as the CFR of patients with DAS <2 h (120 min) was 4.7% (2/43), while for those with DAS >2 h was 29.3% (12/41), P = 0.00. The mean DAS was 149.5 ± 62.9 min.
Furthermore, bowel resection was significantly associated with mortality as the CFR in patients with bowel resection was 23.6% (13/55) and without resection 3.4% (1/29), P = 0.01 [Table 2]b. Likewise, intraoperative blood loss >500 ml was a significant predictor of mortality, CFR >500 ml: 30.8% (12/39), <500 ml: 4.4% (2/45), P = 0.00 [Table 4].
Multivariate analysis of the predictive factors revealed no independent predictors of morbidity P > 0.05. However, elevated serum urea above reference range at presentation and ASA status above IIIE were independent predictors of mortality with P = 0.02 and 0.03, respectively.
| Discussion|| |
Previous studies have shown that age, SIT, preoperative serum levels of potassium, sodium, urea and creatinine, and bowel strangulation were important prognostic factors that determined the outcome of management in patients with MIO.,,,,,, In our study, the mean age of patients was 45.6 years. This is similar to mean age of 45 years recorded in a study by Lawal et al. at Ile Ife and 43.8 years quoted in a Pakistani study by Malik et al., Furthermore, age of patient at presentation did not significantly affect morbidity and mortality in our study, which is in agreement with the findings of Eleweke.
There was a slight male preponderance of 1.1–1 in our study, which is similar to what was obtained by many authors.,,,,,,,,, The gender of the patients did not influence the outcome of treatment in terms of morbidity and mortality. The most common complaint was abdominal pain, which occurred in 98.1% of the patients. This was similar to the findings of Murat et al. of 100% and of Kahn et al. of 98.6%. Abdominal distension was the most common physical finding in this study, which was in conformity with findings by Adesunkanmi and Agbakwuru  in Ile–Ife, Nigeria and by Kuremu and Jumbi in Eldoret, Kenya. The most common co-morbidity in this study was cardiovascular disease (hypertension). Murat et al., in Turkey, also reported cardiovascular disease as the most common co-morbidity in their patients. Co-morbidities did not significantly influence the outcome of management in this study unlike the finding by Murat et al., who recorded comorbidity as an independent predictor of both morbidity and mortality in patients with MIO.
The most common cause of MIO in our study was adhesions (48.6%) followed by tumour (25.7%) and external hernia (15.2%). Adesunkanmi and Agbakwuru  and Lawal et al. at Ile-Ife reported adhesions as the most common cause accounting for 41.5% and 44.4% of cases, respectively. Other recent studies in developing countries found adhesions to be the leading cause of MIO unlike what was obtainable in the past.,,,,, Okenny, however, recorded hernia as the most common cause of MIO. Similarly, Ohene-Yeboah et al. reported that hernia represents 63.2% of all causes, but they agreed that as at the time of his study, which was over a decade ago, the incidence of adhesions had more than doubled. Irabor and Afuwape  also recorded slight preponderance of hernia as aetiology, but the study period spanned a decade and was conducted over a decade ago. A similar study by Madziga and Nuhu  in Maiduguri, which also found hernia as the most frequent cause, was conducted over 7 years ago spanning over 13 years. These studies by Okeny, Ohene, Irabor and Madziga were conducted over a decade ago hence may not represent the current pattern of aetiology of MIO. A study by Adisa and Mbanaso, which spanned 5 years, recorded hernia as the most frequent cause. The study was conducted in both urban and rural centres in Aba, Nigeria. However, they reported a preponderance of adhesions in the urban area. Oladele et al. at Owo also confirmed, in their study, that adhesions were the most common cause of MIO and that hernia was becoming less common. Murat et al. in Turkey and Kuremu  in Eldoret, Kenya recorded adhesions as the most common cause of MIO in their studies. The observed pattern represents a global change in the spectrum of aetiology of MIO over the past few years. A number of recent studies have found adhesions to be replacing hernia as the most common cause of MIO.,,,
The mean DSBP in non-survivors was higher than that of survivors, but the effect of this on both mortality and morbidity was not statistically significant in this study, unlike the findings of the studies of Eleweke  in Nigeria, Murat et al. in Turkey and Malik et al. in Pakistan. This finding in our study is possibly due to delayed surgical intervention in patients that presented relatively early. The delay in surgical intervention possibly nullified the advantages attributable to early presentation. We found that delayed intervention was mainly due to unavailability of blood as well as infrastructural problems such as inadequate power supply. Significantly, the number of patients that presented within 24 h of onset of symptoms in our study (31.4%) was less than that of a similar study by Murat et al.(56.8%). This was possibly due to poor health-seeking behaviour and delayed referral in our subregion.
In our study, 80% of patients had operative intervention and 20% had conservative management. Ohene-Yeboah et al. in Kumasi, Ghana, recorded 89% operative intervention in cases of MIO, which is comparable to our study. Other studies also recorded preponderance of operative intervention over conservative management.,,,, The mean SIT was higher in our study compared to the study by Murat et al. This is possibly due to delayed presentation and/or infrastructural problems in our setting. The mean SIT for survivors (71.9 h) was significantly shorter than for non-survivors (89.3 h); hence, mortality was associated to increasing SIT. This is in consonance with similar studies, which reported that mortality increased proportionately with SIT.,,,,, The operative mortality rate for our patients operated within 24 h of onset of symptoms was 0% while the corresponding value for patients operated after 24 h of onset of symptoms was 17.9%. Our operative mortality rate is similar to that obtained by Andrew  in 1981 who found a mortality rate of 1.4% for patients who arrived within 24 h but 21% for those who came after 24 h. This was mainly due to two major factors: poor general condition (due to dehydration, electrolyte imbalance and metabolic derangement) and the stress of surgery (infection and release of toxic substance from a necrotic/gangrenous bowel). In our study, only 7% of the cases managed by operation had treatment within 24 h, and this was similar to findings of Kuremu and Jumbi.
The failure rate of conservative treatment in this study was 33.3% (including the patient that died while on conservative treatment). This is comparable to the failure rate of 34% recorded by Murat et al. Operative treatment did not have a statistically significant influence on mortality but had a significant effect on morbidity. Hence, the method of treatment did not necessarily determine whether a patient will survive or not, but patients who had operative treatment were more likely to have complications from treatment and/or prolonged hospital stay.
Univariate analysis showed that dehydration, tachycardia, pyrexia, abnormal serum levels of potassium, urea and creatinine, leucocytosis, ASA score > IIIE, bowel resection and operative intervention were significant predictors of morbidity while dehydration, tachycardia (>90 bpm), pyrexia (body temperature >37 C), abnormal serum levels of potassium, urea and creatinine, leucocytosis, ASA score >IIIE, bowel resection, blood loss >500 ml and duration of surgery and anaesthesia longer than 2 h were significant predictors of mortality. Multivariate analysis showed no independent predictor of morbidity, but serum urea above reference range and ASA score above IIIE were independent predictors of mortality. Most of the previous studies did not carry out logistic regression to determine which of the factors independently predicted mortality or morbidity.
The most common post-operative complication was surgical site infection, affecting 39.3% of operated cases. This is similar to findings by Kahn et al. who recorded wound-related sepsis as the most common complication. Other studies also reported wound-related sepsis as the most common complication.,,,
The morbidity rate in our study (54.3%) was higher than that of 41.9% found by Murat et al. This was possibly due to delay in intervention in our setting as only 6% of operated cases had surgery within 24 h in our study whereas 56.8% of operated cases had surgery within 24 h in the study by Murat et al. The mortality rate in our study was 14% which was similar to mortality rates of 14% observed by Lawal et al., 13.2% by Dodiyi-Manuel, 13.3% by Demissie, 12.8% by Murat et al., 12.9% by Okeny et al. and 12% by Ohene-Yeboah et al. This mortality rate of 14% in our study is still unacceptability high especially when compared to mortality rate of 4% in developed countries. The most common cause of death in this study was related to sepsis, which accounted for 66.7% of the mortality, similar to findings by Kahn et al. who also reported sepsis as the most common cause of death.
| Conclusion and Recommendations|| |
Adhesions are the preeminent cause of MIO in this study. This reflects the global change in the spectrum of aetiology of intestinal obstruction and the fact that adhesions as an emerging surgical problem have replaced external hernia as the most common cause of intestinal obstruction even in developing countries. The mortality rate of 14.3% recorded in this study is, however, unacceptably high. Multivariate analysis revealed that elevated serum urea and ASA IIIE score and higher were independent predictors of mortality. These independent variables could be considered surrogates markers of delayed presentation. We would therefore recommend the need for surgeons to adhere to meticulous surgical techniques during laparotomies to reduce adhesions and public health education directed at encouraging early presentation.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
Manuscript was submitted on 25th September 2017. It was assigned to an associate editor on 25th September 2017. Blinded manuscript was sent to four external reviewers (General surgeons) on 6th October 2017. It was accepted with minor revisions by three reviewers and no revisions by one reviewer. Final recommendation for acceptance was on the 18th December 2017.
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[Table 1], [Table 2], [Table 3], [Table 4]