Application of the AAST EGS Grade for Adhesive Small Bowel Obstruction to a Multi-national Patient Population

The utility of a CT grading scale in deciding on surgical intervention for patients with suspected small bowel obstruction

Background

A grading system was developed for computerized tomography (CT) scans evaluating patients with suspected small bowel obstruction (SBO). We hypothesized that patients with a higher grade of suspected SBO on CT scan would be more likely to require surgical intervention.

Methods

Retrospective chart review of patients who presented to the Emergency Room (ER) who had a CT of the abdomen and pelvis for suspected SBO. Patients were divided into 5 groups: Grade 1 (SBO unlikely), Grade 2 (probable partial or early SBO), Grade 3 (probable high grade SBO), Grade 4 (SBO with changes concerning for ischemia) and Not Graded.

Results

The CT scans of 655 patients were graded. Of the 22 patients with a grade 1 SBO, only 1 went for surgery (4.5 %). For grade 2 patients, 23 out of 299 had an operation (7.7 %), for grade 3 it was 84 out of 299 (28.1 %) and for grade 4 SBO, 25 out of 35 patients (71.4 %) had surgery. The p value is <0.00001. The three most common intraoperative findings were SBO obstruction from adhesions alone (48 % of cases), followed by incarcerated hernias (12 %) and ischemic bowel (9 %). Only 8 cases out of 133 operations (6 % of total) had no findings at time of surgery other than dilated bowel.

Conclusions

The CT grading scale for SBO developed at our institution shows excellent correlation between grade and going for surgery, with few negative results, and can be a useful tool among other factors for general surgeons when deciding whether or not to operate on a patient with suspected SBO.

Machine learning based peri-surgical risk calculator for abdominal related emergency general surgery: a multicenter retrospective study

BACKGROUND

Currently, there is a lack of ideal risk prediction tools in the field of emergency general surgery (EGS). The American Association for the Surgery of Trauma recommends developing risk assessment tools specifically for EGS-related diseases. In this study, we sought to utilize machine learning (ML) algorithms to explore and develop a web-based calculator for predicting five perioperative risk events of eight common operations in EGS.

METHOD

This study focused on patients with EGS and utilized electronic medical record systems to obtain data retrospectively from five centers in China. Five ML algorithms, including Random Forest (RF), Support Vector Machine, Naive Bayes, XGBoost, and Logistic Regression, were employed to construct predictive models for postoperative mortality, pneumonia, surgical site infection, thrombosis, and mechanical ventilation >48 h. The optimal models for each outcome event were determined based on metrics, including the value of the Area Under the Curve, F1 score, and sensitivity. A comparative analysis was conducted between the optimal models and Emergency Surgery Score (ESS), Acute Physiology and Chronic Health Evaluation II (APACHE II) score, and American Society of Anesthesiologists (ASA) classification. A web-based calculator was developed to determine corresponding risk probabilities.

RESULT

Based on 10 993 patients with EGS, we determined the optimal RF model. The RF model also exhibited strong predictive performance compared with the ESS, APACHE II score, and ASA classification. Using this optimal model, the authors developed an online calculator with a questionnaire-guided interactive interface, catering to both the preoperative and postoperative application scenarios.

CONCLUSIONS

The authors successfully developed an ML-based calculator for predicting the risk of postoperative adverse events in patients with EGS. This calculator accurately predicted the occurrence risk of five outcome events, providing quantified risk probabilities for clinical diagnosis and treatment.

One-year outcomes following operative or non-operative management of adhesional small bowel obstruction

BACKGROUND

A trial of initial non-operative management is recommended in stable patients with adhesional small bowel obstruction. However, recent retrospective studies have suggested that early operative management may be of benefit in reducing subsequent recurrences. This study aimed to compare recurrence rates and survival in patients with adhesional small bowel obstruction treated operatively or non-operatively.

METHODS

This was a prospective cohort study conducted at six acute hospitals in Denmark, including consecutive patients admitted with adhesional small bowel obstruction over a 4-month interval. Patients were stratified into two groups according to their treatment (operative versus non-operative) and followed up for 1 year after their index admission. Primary outcomes were recurrence of small bowel obstruction and overall survival within 1 year of index admission.

RESULTS

A total of 201 patients were included, 118 (58.7 per cent) of whom were treated operatively during their index admission. Patients undergoing operative treatment had significantly better 1-year recurrence-free survival compared with patients managed non-operatively (operative 92.5 per cent versus non-operative 66.6 per cent, P <0.001). However, when the length of index admission was taken into account, patients treated non-operatively spent significantly less time admitted to hospital in the first year (median 3 days non-operative versus 6 days operative, P <0.001). On multivariable analysis, operative treatment was associated with decreased risks of recurrence (HR 0.22 (95 per cent c.i. 0.10-0.48), P <0.001) but an increased all-cause mortality rate (HR 2.48 (95 per cent c.i. 1.13-5.46), P = 0.024).

CONCLUSION

Operative treatment of adhesional small bowel obstruction is associated with reduced risks of recurrence but increased risk of death in the first year after admission.

REGISTRATION NUMBER

NCT04750811 (http://www.clinicaltrials.gov).prior (registration date: 11 February 2021).

Real-world accuracy of computed tomography in patients admitted with small bowel obstruction: a multicentre prospective cohort study

PURPOSE

Small bowel obstruction (SBO) is a common surgical emergency. Previous studies have shown the value computed tomography (CT) scanning in both confirming this diagnosis and identifying indications for urgent surgical intervention, such as strangulated bowel or closed loop obstructions. However, most of the literature is based on retrospective expert review of previous imaging and little data regarding the real-time accuracy of CT reporting is available. Here, we investigated the real-world accuracy of CT reporting in patients admitted with SBO.

METHODS

This was a multicentre prospective study including consecutive patients admitted with SBO. The primary outcomes were the sensitivity and specificity of CT scanning for bowel obstruction with ischaemia and closed loop obstruction. Data were retrieved from the original CT reports written by on-call radiologists and compared with operative findings.

RESULTS

One hundred seventy-six patients were included, all of whom underwent CT scanning with intravenous contrast followed by operative management of SBO. Bowel obstruction with ischaemia was noted in 20 patients, with a sensitivity and specificity of CT scanning of 40.0% and 85.5%, respectively. Closed loop obstructions were noted in 26 patients, with a sensitivity and specificity of CT scanning of 23.1% and 98.0%, respectively.

CONCLUSIONS

The real-world accuracy of CT scanning appears to be lower than previously reported in the literature. Strategies to address this could include the development of standardised reporting schemas and to increase the surgeon's own familiarity with relevant CT features in patients admitted with SBO.

Impact of COVID-19 on common non-elective general surgery diagnoses

BACKGROUND

During the COVID-19 pandemic, public health and hospital policies were enacted to decrease virus transmission and increase hospital capacity. Our aim was to understand the association between COVID-19 positivity rates and patient presentation with EGS diagnoses during the COVID pandemic compared to historical controls.

METHODS

In this cohort study, we identified patients ≥ 18 years who presented to an urgent care, freestanding ED, or acute care hospital in a regional health system with selected EGS diagnoses during the pandemic (March 17, 2020 to February 17, 2021) and compared them to a pre-pandemic cohort (March 17, 2019 to February 17, 2020). Outcomes of interest were number of EGS-related visits per month, length of stay (LOS), 30-day mortality and 30-day readmission.

RESULTS

There were 7908 patients in the pre-pandemic and 6771 in the pandemic cohort. The most common diagnoses in both were diverticulitis (29.6%), small bowel obstruction (28.8%), and appendicitis (20.8%). The lowest relative volume of EGS patients was seen in the first two months of the pandemic period (29% and 40% decrease). A higher percentage of patients were managed at a freestanding ED (9.6% vs. 8.1%) and patients who were admitted were more likely to be managed at a smaller hospital during the pandemic. Rates of surgical intervention were not different. There was no difference in use of ICU, ventilator requirement, or LOS. Higher 30-day readmission and lower 30-day mortality were seen in the pandemic cohort.

CONCLUSIONS

In the setting of the COVID pandemic, there was a decrease in visits with EGS diagnoses. The increase in visits managed at freestanding ED may reflect resources dedicated to supporting outpatient non-operative management and lack of bed availability during COVID surges. There was no evidence of a rebound in EGS case volume or substantial increase in severity of disease after a surge declined.

Surgical Emergencies in the ICU

Surgical emergencies are common in the critical care setting and require prompt diagnosis and management. Here, we discuss some of the surgical emergencies involving the gastrointestinal, hepatobiliary, and genitourinary sites. In addition, foreign body aspiration and necrotizing soft-tissue infections have been elaborated. Clinicians should be aware of the risk factors, keys examination findings, diagnostic modalities, and medical as well as surgical treatment options for these potentially fatal illnesses.

Management and short-term outcomes of patients with small bowel obstruction in Denmark: a multicentre prospective cohort study

AIMS

The optimal management of small bowel obstruction (SBO) remains a matter of debate and treatment varies internationally. In Denmark, a more surgically aggressive strategy has traditionally been used, but to what extent patient outcomes differ from international reports is unknown. This study aimed to describe the current management and outcomes of patients admitted with SBO in Denmark.

METHODS

This was a prospective cohort study conducted at six acute hospitals in Denmark over a 4-month period. Patients aged ≥ 18 years with a clinical or radiological diagnosis of SBO were eligible. Primary outcomes were 30 day morbidity and mortality rates.

RESULTS

316 patients were included during the study period. The median age was 72 years and 56% were female. Diagnosis was made by computed tomography (CT) in 313 patients (99.1%), with the remaining three diagnosed clinically. Non-operative management was the initial strategy in 152 patients (48.1%) and successful in 119 (78.3%). Urgent surgery was performed in the remaining 164 (51.9%), with a laparoscopic approach used in 84 patients (51.2%). The entire cohort had a 30 day mortality rate of 7.3% and a 30 day morbidity rate of 17.1%.

CONCLUSIONS

The management of SBO in Denmark differs markedly to previous international reports, with an almost ubiquitous use of CT for diagnosis and a high proportion of patients undergoing urgent surgery. Despite higher rates of surgery, patient outcomes are broadly similar to reports of more conservative strategies, perhaps due to a reduction in delayed operations.

TRIAL REGISTRATION

Trial registration number: NCT04750811. Trial registration date: 11/02/2021.

Predicting the Need for Surgery in Uncomplicated Adhesive Small Bowel Obstruction: A Scoring Tool

INTRODUCTION

Nonoperative treatment can be attempted for uncomplicated adhesive small bowel obstruction (ASBO), but carries a risk of delayed surgery. Highlighting initial parameters predicting risk of failure of nonoperative management would be of great interest.

METHODS

Patients initially managed conservatively for uncomplicated ASBO were retrospectively analyzed. Univariate and multivariate analysis were performed to identify predictive failure's factors. Based on the risk factors, a score was created and then prospectively validated in a different patients' population.

RESULTS

Among 171 patients included, 98 (57.3%) were successfully managed conservatively. In a multivariate analysis, three independent nonoperative management failure's factors were identified: Charlson Index ≥4 (P = 0.016), distal obstruction (P = 0.009), and maximum small bowel diameter over vertical abdominal diameter ratio >0.34 (P = 0.023). A score of two or three was associated with a risk of surgery of 51.4% or 70.3% in the retrospective analysis and 62.2% or 75% in the validation cohort, respectively.

CONCLUSIONS

This clinical-radiological score may help guide surgical decision-making in uncomplicated ASBO. A high score (≥2) was predictive of failure of nonoperative management. This tool could assist surgeons to determine who would benefit from early surgery.

Factors associated with potentially avoidable interhospital transfers in emergency general surgery-A call for quality improvement efforts

BACKGROUND

Emergency general surgery conditions are common, require urgent surgical evaluation, and are associated with high mortality and costs. Although appropriate interhospital transfers are critical to successful emergency general surgery care, the performance of emergency general surgery transfer systems remains unclear. We aimed to describe emergency general surgery transfer patterns and identify factors associated with potentially avoidable transfers.

METHODS

We performed a retrospective cohort study of emergency general surgery episodes in 8 US states using the 2016 Healthcare Cost and Utilization Project State Inpatient and Emergency Department Databases and the American Hospital Association Annual Surveys. We identified Emergency Department-to-Inpatient and Inpatient-to-Inpatient interhospital emergency general surgery transfers. Potentially avoidable transfers were defined as discharge within 72 hours after transfer without undergoing any procedure or operation at the destination hospital. We examined transfer incidence and characteristics. We performed multilevel regression examining patient-level and hospital-level factors associated with potentially avoidable transfers.

RESULTS

Of 514,410 adult emergency general surgery episodes, 26,281 (5.1%) involved interhospital transfers (Emergency Department-to-Inpatient: 65.0%, Inpatient-to-Inpatient: 35.1%). Over 1 in 4 transfers were potentially avoidable (7,188, 27.4%), with the majority occurring from the emergency department. Factors associated with increased odds of potentially avoidable transfers included self-pay (versus government insurance, odds ratio: 1.26, 95% confidence interval: 1.09-1.45, P = .002), level 1 trauma centers (versus non-trauma centers, odds ratio: 1.24, 95% confidence interval: 1.05-1.47, P = .01), and critical access hospitals (versus non-critical access, odds ratio: 1.30, 95% confidence interval: 1.15-1.47, P < .001). Hospital-level factors (size, trauma center, ownership, critical access, location) accounted for 36.1% of potentially avoidable transfers variability.

CONCLUSION

Over 1 in 4 emergency general surgery transfers are potentially avoidable. Understanding factors associated with potentially avoidable transfers can guide research, quality improvement, and infrastructure development to optimize emergency general surgery care.

Análisis clínico-tomográfico en obstrucción de intestino delgado por adherencias según el sitio de obstrucción en la tomografía

Introducción. Las adherencias postoperatorias son la causa más frecuente de obstrucción de intestino delgado. La clínica sugiere el diagnóstico, pero de manera poco precisa la causa y el sitio de la obstrucción. La tomografía computarizada contrastada es el estudio óptimo y permite identificar de manera oportuna a los pacientes que requieren intervención quirúrgica. El objetivo de este estudio fue analizar la correlación entre la clínica y el sitio de obstrucción detectado en la tomografía computarizada contrastada de abdomen, en pacientes con sospecha diagnóstica de obstrucción de intestino delgado por adherencias. Métodos. Estudio prospectivo, transversal y analítico de pacientes con sospecha clínica de obstrucción de intestino delgado por adherencias y antecedentes quirúrgicos y su correlación con el sitio de obstrucción detectado en la tomografía computarizada de abdomen contrastada, de pacientes atendidos entre marzo de 2016 y febrero de 2019 en un hospital de segundo nivel. Resultados. Se incluyeron 41 pacientes, la media de edad fue de 59 años y el género masculino el más comprometido (68,3 %, n=28); la ausencia de evacuaciones estuvo presente en 97,5 % (p=0,026). La tomografía computarizada contrastada mostró el sitio de obstrucción en 73 % de los pacientes y la localización de la obstrucción más prevalente fue en íleon distal (31,7 %, n=13). Se asoció a leucocitosis (p=0,041) y a dolor más intenso (p=0,049), sin presentar irritación peritoneal. Conclusión. La obstrucción localizada en el íleon distal se caracterizó por presentar más dolor y mayor recuento leucocitario, sin correlación como factor de riesgo para requerir tratamiento quirúrgico.

Evaluating the association between American Association for the Surgery of Trauma emergency general surgery anatomic severity grades and clinical outcomes using national claims data

BACKGROUND

Emergency general surgery (EGS) encompasses a heterogeneous population of acutely ill patients, and standardized methods for determining disease severity are essential for comparative effectiveness research and quality improvement initiatives. The American Association for the Surgery of Trauma (AAST) has developed a grading system for the anatomic severity of 16 EGS conditions; however, little is known regarding how well these AAST EGS grades can be approximated by diagnosis codes in administrative databases.

METHODS

We identified adults admitted for 16 common EGS conditions in the 2012 to 2017q3 National Inpatient Sample. Disease severity strata were assigned using International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) and International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) diagnosis codes based on AAST EGS anatomic severity grades. We evaluated whether assigned EGS severity (multiple strata or dichotomized into less versus more complex) were associated with in-hospital mortality, complications, length of stay, discharge disposition, and costs. Analyses were adjusted for age, sex, comorbidities, hospital traits, geography, and year.

RESULTS

We identified 10,886,822 EGS admissions. The number of anatomic severity strata derived from ICD-9/10-CM codes varied by EGS condition and by year. Four conditions mapped to four strata across all years. Two conditions mapped to four strata with ICD-9-CM codes but only two or three strata with ICD-10-CM codes. Others mapped to three or fewer strata. When dichotomized into less versus more complex disease, patients with more complex disease had worse outcomes across all 16 conditions. The addition of multiple strata beyond a binary measure of complex disease, however, showed inconsistent results.

CONCLUSION

Classification of common EGS conditions according to anatomic severity is feasible with International Classification of Diseases codes. No condition mapped to five distinct severity grades, and the relationship between increasing grade and outcomes was not consistent across conditions. However, a standardized measure of severity, even if just dichotomized into less versus more complex, can inform ongoing efforts aimed at optimizing outcomes for EGS patients across the nation.

LEVEL OF EVIDENCE

Prognostic, level III.

Comparison of American Association for the Surgery of Trauma grading scale with modified Hinchey classification in acute colonic diverticulitis: A pilot study

BACKGROUND

The American Association for the Surgery of Trauma (AAST) developed a severity scale for surgical conditions, including diverticulitis. The Hinchey classification requires operative intervention yet remains the established scoring system for acute diverticulitis. This is a pilot study to compare the AAST grading scale for acute colonic diverticulitis with the traditional Hinchey classification. We hypothesize that the AAST classification scale is equivalent to the Hinchey in predicting outcomes.

METHODS

This is a retrospective cohort study at an academic medical center. A consecutive sample of patients with acute diverticulitis and computed tomography imaging was reviewed. Chart review identified demographic and physiologic data with interventional and clinical outcomes. Each computed tomography scan was assigned AAST and modified Hinchey classification scores by a radiologist. Multivariate regression and receiver operating characteristic curve analysis compared six outcomes: need for procedure, complication, intensive care unit (ICU) admission, length of stay, 30-day readmission, and mortality.

RESULTS

One hundred twenty-nine patients were included. Of the total patients, 42.6% required procedural intervention, 21.7% required ICU admission, 18.6% were readmitted, and 6.2% died. Both AAST and Hinchey predicted the need for operation (AAST odds ratios, 1.55, 12.7, 18.09, and 77.24 for stages 2-5; Hinchey odds ratios, 8.85, 11.49, and 22.9 for stages 1b-3, stage 4 predicted perfectly). The need for operation c-statistics (area under the curve) for AAST and Hinchey was 0.80 and 0.83 for Hinchey and AAST, respectively (p = 0.35). The complication c-statistics curve for AAST and Hinchey was 0.83 and 0.80, respectively (p = 0.33). The AAST and Hinchey scores were less predictive for ICU admission, readmission, and mortality with c-statistics of less than 0.80.

CONCLUSION

The AAST grading of acute diverticulitis is equivalent to the modified Hinchey classification in predicting procedural intervention and complications. The AAST system may be preferable to Hinchey because it can be applied preoperatively. Although this pilot study demonstrated that the AAST score predicts surgical need, a larger study is required to evaluate the AAST score for other outcomes.

LEVEL OF EVIDENCE

Prognostic and epidemiological study, level III.

Validation of the American Association for the Surgery of Trauma grading system for acute mesenteric ischemia-More than anatomic severity is needed to determine risk of mortality

BACKGROUND

Acute mesenteric ischemia (AMI) is a highly morbid disease with a diverse etiology. The American Association for the Surgery of Trauma (AAST) proposed disease-specific grading scales intended to quantify severity based upon clinical, imaging, operative, and pathology findings. This grading scale has not been yet been validated for AMI. The goal of this study was to evaluate the correlation between the grading scale and complication severity.

METHODS

Patients for this single center retrospective chart review were identified using diagnosis codes for AMI (ICD10-K55.0, ICD9-557.0). Inpatients >17 years old from the years 2008 to 2015 were included. The AAST grades (1-5) were assigned after review of clinical, imaging (computed tomography), operative and pathology findings. Two raters applied the scales independently after dialog with consensus on a learning set of cases. Mortality and Clavien-Dindo complication severity were recorded.

RESULTS

A total of 221 patients were analyzed. Overall grade was only weakly correlated with Clavien-Dindo complication severity (rho = 0.27) and mortality (rho = 0.21). Computed tomography, pathology, and clinical grades did not correlate with mortality or outcome severity. There was poor interrater agreement between overall grade. A mortality prediction model of operative grade, use of vasopressors, preoperative serum creatinine and lactate levels showed excellent discrimination (c-index = 0.93).

CONCLUSION

In contrast to early application of other AAST disease severity scales, the AMI grading scale as published is not well correlated with outcome severity. The AAST operative grade, in conjunction with vasopressor use, creatinine, and lactate were strong predictors of mortality.

LEVEL OF EVIDENCE

Prognostic study, III.

Disease Severity and Cost in Adhesive Small Bowel Obstruction

BACKGROUND

Adhesive small bowel obstruction (ASBO) severity has been associated with important clinical outcomes. However, the impact of ASBO severity on hospitalization cost is unknown. The American Association for the Surgery of Trauma (AAST) developed an Emergency General Surgery (EGS) disease severity grading system for ASBO. We stratified patients' ASBO severity and captured hospitalization costs hypothesizing that increased disease severity would correlate with greater costs.

METHODS

This was a single-center study of hospitalized adult patients with SBO during 2015-2017. Clinical data and estimated total cost (direct + indirect) were abstracted. AAST EGS grades (I-IV) stratified disease severity. Costs were normalized to the median grade I cost. Univariate and multivariate analyses evaluated the relationship between normalized cost and AAST EGS grade, length of hospital and ICU stay, operative time, and Charlson comorbidity index.

RESULTS

There were 214 patients; 119 (56%) were female. AAST EGS grades included: I (62%, n = 132), II (23%, n = 49), III (7%, n = 16), and IV (8%, n = 17). Relative to grade I, median normalized cost increased by 1.4-fold for grade II, 1.6-fold for grade III, and 4.3-fold for grade IV disease. No considerable differences in patient comorbidity between grades were observed. Pair-wise comparisons demonstrated that grade I disease cost less than higher grades (corrected p < 0.001). Non-operative management was associated with lower normalized cost compared to operative management (1.1 vs. 4.5, p < 0.0001). In patients who failed non-operative management, normalized cost was increased 7.2-fold. Collectively, the AAST EGS grade correlated well with cost (Spearman's p = 0.7, p < 0.0001). After adjustment for covariates, AAST EGS grade maintained a persistent relationship with cost.

CONCLUSION

Increasing ASBO severity is independently associated with greater costs. Efforts to identify and mitigate costs associated with this burdensome disease are warranted.

LEVEL OF EVIDENCE

III, economic/decision.

National prospective cohort study of the burden of acute small bowel obstruction

Background

Small bowel obstruction is a common surgical emergency, and is associated with high levels of morbidity and mortality across the world. The literature provides little information on the conservatively managed group. The aim of this study was to describe the burden of small bowel obstruction in the UK.

Methods

This prospective cohort study was conducted in 131 acute hospitals in the UK between January and April 2017, delivered by trainee research collaboratives. Adult patients with a diagnosis of mechanical small bowel obstruction were included. The primary outcome was in‐hospital mortality. Secondary outcomes included complications, unplanned intensive care admission and readmission within 30 days of discharge. Practice measures, including use of radiological investigations, water soluble contrast, operative and nutritional interventions, were collected.

Results

Of 2341 patients identified, 693 (29·6 per cent) underwent immediate surgery (within 24 h of admission), 500 (21·4 per cent) had delayed surgery after initial conservative management, and 1148 (49·0 per cent) were managed non‐operatively. The mortality rate was 6·6 per cent (6·4 per cent for non‐operative management, 6·8 per cent for immediate surgery, 6·8 per cent for delayed surgery; P = 0·911). The major complication rate was 14·4 per cent overall, affecting 19·0 per cent in the immediate surgery, 23·6 per cent in the delayed surgery and 7·7 per cent in the non‐operative management groups (P < 0·001). Cox regression found hernia or malignant aetiology and malnutrition to be associated with higher rates of death. Malignant aetiology, operative intervention, acute kidney injury and malnutrition were associated with increased risk of major complication.

Conclusion

Small bowel obstruction represents a significant healthcare burden. Patient‐level factors such as timing of surgery, acute kidney injury and nutritional status are factors that might be modified to improve outcomes.