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Emergent Surgery for Small Bowel Obstruction
R. Armour Forse MD, PhD, FACS, FRCS(C),FACCCMDepartment of Surgery
Creighton University, Omaha, Nebraska
Nothing to disclose
Except
I am a practicing surgeon who still deals with this problem
Case 1 • 75 year old woman admitted with acute SBO.• From nursing home partially disabled, DNR +• Previous surgery remote TAH.• No cardiac, pulmonary, liver or renal problems.• Albumin normal• ASA 3, decide to operate after 24 hours• Not on ventilator• OR – 100 minutes• Clean contaminated surgery
Risk Assessment Case 1
• Morbidity– a) 20, b) 40, c) 50 , d) 60, e) 70
• Mortality – a) 20, b) 40, c) 50 , d) 60, e) 70
Case 2 • 75 year old woman admitted with acute SBO.• From nursing home fully disabled, DNR +• Previous surgery remote TAH.• Previous cardiac stents, COPD, SGOT=100, and creatinine = 2.3.
• Albumin abnormal, considered malnoursihed.• ASA 4, decide to operate urgently, septic.• Intubated and ventilated before OR. • OR – 100 minutes• Clean contaminated surgery
Risk Assessment Case 2
• Morbidity– a) 20, b) 40, c) 60 , d) 70, e) 90
• Mortality – a) 20, b) 40, c) 60 , d) 70, e) 90
Introduction
• Small bowel obstruction is a very common surgical problem. Very little has changed with regard to the surgical techniques. If acute with no previous surgery then surgery intervention sooner, directed by the principle of “never let the sun set on a bowel obstruction ”. With previous surgery and no hernias we often advocate watching.
•Not all small bowel obstructions are the same and they can be associated with the risk of ischemia. Cases with ischemia are an emergency. In fact ischemia can be the cause of the obstruction. These cases have the highest risks and often are associated with the poorest outcomes, associated with a significant morbidity and mortality rate which has remained largely unchanged over the last few decades.
Introduction con’t
The recent advances are not technical but more focused on the decision of whether to operate or not.
The surgeon can find it very difficult to determine if there is bowel ischemia, and in addition even harder to predict the morbidity and mortality with any surgery. Knowledge of preoperative risk factors and an estimation of morbidity and mortality would aid in decision making for physicians and patients
This can be a factor in the decisions regarding surgery such as the timing, the extent of the surgery and whether to operate or not.
Such information can help post operatively in treatment decisions.
Review of NSQIP Data with Specific Aims
• To identify preoperative and intra‐operative risk factors associated with post‐operative outcomes in patients with bowel ischemia and poor outcomes.
• To develop a reliable and clinically meaningful morbidity and mortality risk calculator which would aid in surgical decision making and informed patient consent in patients with risk of bowel ischemia who are critically ill and will likely need a bowel resection.
Methodology
• The American College of Surgeons’(ACS) National Surgical Quality Improvement Program (NSQIP) database was used for the study.
• Data were obtained from the 2007 and 2008 ACS NSQIP participant user data files.
• NSQIP collects 136 perioperative variables for patients undergoing major surgical procedures.
• Only patients undergoing bowel resection for bowel ischemia in the dataset were included using American Medical Association’s Current procedural terminology (CPT) codes for bowel surgeries.
Outcome
• Outcome variables were morbidity (occurrence of major complications) and mortality.
• Outcomes are assessed up to 30 postoperative days in NSQIP except for length of stay which is tracked up to discharge from hospital.
Methodology
•A risk calculator was developed which is in the form of an interactive spreadsheet that accepts patients covariate information.
• It returns estimated probability percentage of morbidity and mortality based on the statistical models used.
Results
Demographics:
• 861 patients underwent bowel resection for bowel ischemia.
• 53.7% were females and 46.3% males.
• Median age – 69 years ( interquartile range(IQR)‐ 58‐79 years).
• Median BMI‐ 28Kg/m2 ( IQR‐23.6‐32.7).
Comorbidities and therapy characteristicsPreoperative Comorbidity/ Therapy Number of patients (percentage)
Hypertension 628 (72.9%)
Renal – renal failurePreopeative Dialysis
105 (12.2%)110 (12.8%)
Cardiac‐Congestive heart failure,Myocardial infarction in last 6 months
65(7.4%)58 (6.7%)
Pulmonary‐COPDDyspneaPneumonia
155(18%)263 (30.5%)48 (5.6%)
Neurologic‐coma,Stroke/ TIA
17(2%)146 (16.95%)
Liver‐ ascitisAbnormal bilirubin
121 (14%)168 (19.5%)
Alcohol intake 35 (4.1%)
Smoking 227 (26.4%)
Emergency surgery (defined as within 12 hours of admission)
674 (78%)
Concomitant revascularisation 8 (0.93%)
Outcomes
Factor N (out of 816) %50
MajorVentilatorSeptic shockPneumonia SepsisRe‐intubationAcute renal failureCardiac arrestOrgan space infectionDeep venous thrombosisTransfusionDeep wound infectionWound dehisenceRenal insufficiency ComaStrokeMyocardial infarctionPulmonary Embolus
344131128998650483932322422221712105
4015.214.911.5107.75.85.64.53.72.82.62.62.01.41.20.6
MinorSuperficial wound infectionUrinary tract infection
5350
6.25.8
Outcomes
Parameter Result
30 day morbidity rate 56.6%
30 day mortality rate 27.9%
Median length of hospital stay of non‐ survivors
6 days( IQR‐ 1‐14 days)
Median length of stay for survivors
11 days( IQR‐ 6‐21 days)
Median operative time 103 minutes ( IQR‐ 75‐143 minutes)
Return to OR within 30 days 266 (30.9%)
Significant factors for postoperative major morbidityon multivariate analysis
Factor Odds ratio 95% confidence interval
Admission from chronic care facility vs home
4.17 1.65‐10.53
Preoperative sepsis 2.45 1.43‐4.18
Recent myocardial infarction within last 6 months
2.29 1.01‐5.18
Preoperative ventilator dependence 1.95 1.18‐3.22
Preoperative acute renal failure 1.93 1.03‐3.61
Emergency surgery 1.62 1.05‐2.49
Increased operative time per minute 1.003 1.001‐1.006
ASA ClassClass 4 vs 2Class 4 vs 3Class 3 vs 2
2.721.721.59
1.62‐4.571.12‐2.631.02‐2.47
Factor Odds ratio 95% confidence interval
Preoperative coma 7.81 1.83‐33.33
Preoperative do not resuscitate order 3.19 1.19‐8.55
Open wound 2.35 1.30‐4.26
Elevated SGOT 2.25 1.46‐3.47
Functional status:Partially dependent vs independenttotally dependent vs independent
2.041.88
1.21‐3.441.12‐3.15
Preoperative sepsis 2.02 1.12‐3.66
Low albumin 1.93 1.13‐3.28
Dirty versus clean contaminated case 1.91 1.15‐3.17
Increase in age per year 1.039 1.023‐1.055
Higher ASA class eg. Class 4 vs 2 6.90 2.70‐17.54
Significant factors for postoperative mortalityon multivariate analysis
Factors not associated with adverse postoperative outcomes:
• Segment of bowel involved (small bowel vs colon).
• Type of resection- creation of ostomy vs primary anastomosis.
The following 18 parameters are used to calculate the estimated risk probability:
• Acute renal failure• Admission from home vs health care facility• Age• Albumin• ASA class• Previous cardiac surgery• Coma preoperatively• COPD• DNR order preoperatively• Functional status prior to surgery• Myocardial infarction within 6 months• Nature of surgery- emergent vs elective• Open wound• Operative time• Sepsis preoperatively• SGOT preoperatively• On ventilator preoperatively• Wound classification in the operation
The risk model and calculator
• Significant predictors from the multivariate analysis were included.
C‐statistic (discrimination)
Hosmer‐lemeshow goodness of fit test (calibration)‐chi square value
Morbidity model 0.794 4.96(p=0.762)
Mortality model 0.837 6.76 (p=0.563)
•Both indicate excellent discrimination and calibration for both the morbidity and the mortality models.
• Risk calculator is available online at http://www.surgicalriskcalculator.com/ami‐risk‐calculator
Case 1 • 75 year old woman admitted with acute SBO.• From nursing home partially disabled, DNR +• Previous surgery remote TAH.• No cardiac, pulmonary, liver or renal problems.• Albumin normal• ASA 3, decide to operate after 24 hours• Not on ventilator• OR – 100 minutes• Clean contaminated surgery
Risk Assessment Case 1
• Morbidity– a) 20, b) 40, c) 50 , d) 60, e) 70 answer 67.9%
• Mortality – a) 20, b) 40, c) 50 , d) 60, e) 70 answer 45.1%
Case 2 • 75 year old woman admitted with acute SBO.• From nursing home fully disabled, DNR +• Previous surgery remote TAH.• Previous cardiac stents, COPD, SGOT=100, and creatinine = 2.3.
• Albumin abnormal, considered malnoursihed.• ASA 4, decide to operate urgently, septic.• Intubated and ventilated before OR. • OR – 100 minutes• Clean contaminated surgery
Risk Assessment Case 2
• Morbidity– a) 20, b) 40, c) 60 , d) 70, e) 90 answer 95.9%
• Mortality – a) 20, b) 40, c) 60 , d) 70, e) 90 answer 82.3%
Limitations of the study
• Specific covariates attributable to bowel ischemia such as patient symptomatology, peritoneal signs, serum lactate levels, a history of atrial fibrillation, the timing of operation, and the nature of the reoperations are not part of the existing NSQIP database, but can play an important role (targeted risk factors) .
• The exact etiology of the bowel ischemia may be an independent factor influencing this outcome and this information is not available in the NSQIP database (targeted etiology factors).
• The risk calculator is yet to be validated, waiting for a larger dataset.
Procedure 30 Day Mortality for Patients With
Disseminated Cancer Whose Procedure Was an Emergency
30 Day Mortality for Patients With
Disseminated Cancer Whose Procedure Was
Not an Emergency
P Values
Exploration of the Abdomen
19/43= 44.2% 15/117 or 12.3% P= <.0001
Small Bowel Anastomosis
4/12=33.3% 2/36=5.6% P= .0021
Total Colectomy 8/26= 30.8% 3/74=4.1% P= <.0001
Resection of Small Bowel
14/46= 28.3% 12/122=9.8% P= <.0001
Cholecystectomy 6/26= 23% 4/79=5.1% P= <.0001
Colon Resection 20/90= 22.2% 18/265=6.8% P= <.0001
Colostomy 3/16= 18.8% 8/87=9.2% P= <.0001
All Patients 133/468=28.4% 163/2782=5.9%
Produced by TonyPesavento
Conclusion
•Morbidity and mortality rates following bowel resection for bowel ischemia are very high.
•Admission from chronic care facility, preoperative Do Not Resuscitate status, cardiac, pulmonary and renal comorbidities, dependent functional status, emergency procedure, class 4 wound and operative time are associated with a significantly increased postoperative risk.
•This risk calculator is based on the ACS NSQIP data and was developed to accurately estimate postoperative morbidity and mortality after bowel resection for bowel ischemia.
•The risk calculator is designed to aid in surgical decision‐making, informed patient consent and management planning in critically ill who have had surgery with the finding of ischemia bowel.
Thanks ‐you
Acknowledgments
Prateek K. Gupta MD1
Bala Natarajan MBBS1
Xiang Fang PhD2
1‐Department of Surgery2‐ Biostatistical Core
Creighton University, Omaha, Nebraska
Outcomes
Introduction
• Acute mesenteric ischemia (AMI) is an uncommon surgical emergency which occurs due to impairment of mesenteric arterial or venous circulation.
• It is associated with a significant morbidity and mortality rate which has remained largely unchanged over the last few decades.
• Given such poor outcome, knowledge of preoperative risk factors and an estimation of morbidity and mortality would aid in decision making for physicians and patients.
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