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An Obstructed View
PERIOPERATIVE GRAND ROUNDS
An Obstructed View THE CASE A 66-year-old man presented to the emergency department with subacute abdominal pain that had intensified the previous evening. He reported relatively mild cramping in the midabdomen for the past two to three weeks. The previous night, soon after eating dinner, he developed severe midabdominal pain that did not radiate or remit. He reported no nausea, vomiting, diarrhea, fevers, chills, weight loss, or night sweats. He had a normal bowel movement the previous day. The patient had never undergone a colonoscopy. Initially, the patient had stable vital signs, a tender abdomen without rebound or guarding, and unremarkable laboratory test results. A computed tomography (CT) scan of his abdomen and pelvis showed mild dilation of the ascending, transverse, and proximal descending colon with a possible “transition point concerning for stricture/mass or physiologic peristalsis.” The patient was admitted to medicine service for observation, pain management, and abdominal examination. Approximately 48 hours after hospitalization, the patient’s abdomen became more distended, with increased pain and tenderness with rebound upon examination. Personnel requested surgical consultation. After the surgeons reviewed the images and examined the patient, they immediately took him to the OR and found an obstructive mass with associated perforation. The patient experienced a prolonged postoperative course with intra-abdominal infection before ultimately dying. The institution formally reviewed the case because of concerns regarding a possible delay in treatment and surgical consultation.
Approximately 75% of these intestinal obstructions are caused by adhesions from previous operations.6 The remaining obstructions result from Crohn’s disease, neoplasia, hernia (internal or abdominal wall), radiation, congenital adhesions, or other causes.6 Early on, hyperperistalsis may produce loose stools, but by the time the patient presents to the physician, diarrhea is rarely a prominent symptom. Symptoms may include abdominal distension, tenderness, oliguria, tachycardia, dry mucous membranes, anddin some casesd peritonitis. Bowel auscultation is not useful; all bowel sounds are compatible with obstruction. As the condition progresses, the obstructed bowel becomes edematous, dilated, and overgrown with bacteria. When luminal pressure exceeds capillary perfusion pressure, ischemia of the intestinal wall occurs, followed by peritonitis, perforation, and sepsis. If this process continues uninterrupted, death may result from either septic or hypovolemic shock. Initial evaluation should include assessment of blood cell counts, electrolytes, creatinine, urine output, and vital signs. Both metabolic alkalosis (from vomiting) and metabolic acidosis can be seen.1-3 Initial management is bowel rest, isotonic crystalloid solution resuscitation, serial abdominal examinations, and nasogastric tube suction (which may be omitted if the patient is not retching). The best imaging for intestinal obstruction is a CT scan of the abdomen and pelvis with IV contrast and without oral contrast.1,7-11 Plain films of the abdomen are usually not continued on page 65
DISCUSSION This case illustrates the difficulty of diagnosing a bowel obstruction from clinical features and imaging. For more than 50 years, there have been numerous failed attempts to identify predictors of strangulating obstruction based on symptoms, signs, laboratory tests, and imaging characteristics.1-3 There is simply no good predictor, or combination of predictors, that allows for accurate identification of a bowel obstruction. This fact is disheartening, given that intestinal obstruction is one of the most common surgical emergencies in the United States, leading to more than 300,000 operations per year.4,5
This content is adapted from AHRQ WebM&M (Morbidity & Mortality Rounds on the Web) with permission from the Agency for Healthcare Research and Quality. The original commentary was written by Jonathan Carter, MD, and was adapted for this article by Nancy J. Girard, PhD, RN, FAAN, consultant/owner, Nurse Collaborations, Boerne, TX. (Citation: Carter J. An obstructed view. AHRQ WebM&M [serial online]. https://psnet.ahrq.gov/webmm/ case/361/an-obstructed-view. Published October 2015. Accessed January 30, 2017.) Dr Girard has no declared affiliation that could be perceived as posing a potential conflict of interest in the publication of this article. http://dx.doi.org/10.1016/j.aorn.2017.03.013 ª AORN, Inc, 2017
92 j AORN Journal
www.aornjournal.org
July 2017, Vol. 106, No. 1
Perioperative Grand Rounds
continued from page 92
PERIOPERATIVE POINTS
helpful. Classic findings for intestinal obstruction are a proximally dilated bowel (less than 3 cm) with air-fluid levels terminating in a transition point, followed by a decompressed bowel and colon. Findings that raise concern for strangulation are ascites, a thick-walled bowel, segmental mesenteric fluid, free air, mesenteric stranding, decreased mucosal enhancement, pneumatosis, and a closed loop (ie, a dilated bowel pinched at both ends).
Strangulating intestinal obstruction remains challenging to diagnose. Obstructions in patients without histories of abdominal surgery are uncommon and warrant early surgical evaluation. Obstructions that do not resolve within 72 hours generally require surgery. For any patient admitted with a possible urgent bowel obstruction, communication with the OR should occur immediately upon diagnosis to prepare staffing and surgical space.
After establishing an intestinal obstruction diagnosis, personnel should determine whether any features of strangulation are present. Symptoms may include fever, tachycardia, leukocytosis, constant pain (as opposed to colicky pain), and peritonitis. Unfortunately, even these classic signs are of poor predictive value. One multivariate analysis showed that decreased mucosal enhancement was the only independent predictor of strangulating obstruction.1 Decreased mucosal enhancement on CT is a powerful predictor of strangulating obstruction anddwhen accompanied by concerning CT findings, as noted abovedis an indication for surgical exploration. In this case, several features warranted early surgical evaluation. First, the patient had not undergone a previous abdominal operation, making adhesion an unlikely culprit. Of the remaining causes of obstruction, most require an operation. Second, there is a strong argument for early laparoscopic evaluation in this setting, both to confirm the diagnosis and to treat the offending lesion that may be found with laparoscopy.12 Third, the radiographic reporting deserves scrutiny: Was the transition point in the small bowel or colon? Were any concerning features of strangulation present? Is neoplasia suspected? In this case, it is unlikely that the patient progressed to perforation within 48 hours without any subtle warning signs on the index CT; these signs may not have appeared in the dictated report. As this case illustrates, a patient can have strangulated or obstructed bowel with no clinical or radiographic predictors, so time should also be considered a diagnostic test. Using close observation and serial examinations, a physician can better understand the trajectory of the patient’s illness. A practice pearl: “Obstructions destined to resolve nonoperatively generally do so within 72 hours. A patient who is getting sicker needs urgent surgical evaluation.”
www.aornjournal.org
References 1. Jancelewicz T, Vu LT, Shawo AE, Yeh B, Gasper WJ, Harris HW. Predicting strangulated small bowel obstruction: an old problem revisited. J Gastrointest Surg. 2009;13(1):93-99. 2. Sarr MG, Bulkley GB, Zuidema GD. Preoperative recognition of intestinal strangulation obstruction. Prospective evaluation of diagnostic capability. Am J Surg. 1983;145(1):176-182. 3. Silen W, Hein MF, Goldman L. Strangulation obstruction of the small intestine. Arch Surg. July 1962;85:121-129. 4. Scott FI, Osterman MT, Mahmoud NN, Lewis JD. Secular trends in small-bowel obstruction and adhesiolysis in the United States: 1988e2007. Am J Surg. 2012;204(3):315-320. 5. Ray NF, Denton WG, Thamer M, Henderson SC, Perry S. Abdominal adhesiolysis: inpatient care and expenditures in the United States in 1994. J Am Coll Surg. 1998;186(1):1-9. 6. Miller G, Boman J, Shrier I, Gordon PH. Etiology of small bowel obstruction. Am J Surg. 2000;180(1):33-36. 7. Zalcman M, Sy M, Donckier V, Closset J, Gansbeke DV. Helical CT signs in the diagnosis of intestinal ischemia in small-bowel obstruction. AJR Am J Roentgenol. 2000;175(6):1601-1607. 8. Sheedy SP, Earnest FIV, Fletcher JG, Fidler JL, Hoskin TL. CT of small-bowel ischemia associated with obstruction in emergency department patients: diagnostic performance evaluation. Radiology. 2006;241(3):729-736. 9. Kim JH, Ha HK, Kim JK, et al. Usefulness of known computed tomography and clinical criteria for diagnosing strangulation in smallbowel obstruction: analysis of true and false interpretation groups in computed tomography. World J Surg. 2004;28(1):63-68. 10. Ha HK, Kim JS, Lee MS, et al. Differentiation of simple and strangulated small-bowel obstructions: usefulness of known CT criteria. Radiology. 1997;204(2):507-512. 11. Donckier V, Closset J, Van Gansbeke D, et al. Contribution of computed tomography to decision making in the management of adhesive small bowel obstruction. Br J Surg. 1998;85(8):1071-1074. 12. Franklin ME Jr, Gonzalez JJ Jr, Miter DB, Glass JL, Paulson D. Laparoscopic diagnosis and treatment of intestinal obstruction. Surg Endosc. 2004;18(1):26-30.
AORN Journal j 65
An Obstructed View THE CASE A 66-year-old man presented to the emergency department with subacute abdominal pain that had intensified the previous evening. He reported relatively mild cramping in the midabdomen for the past two to three weeks. The previous night, soon after eating dinner, he developed severe midabdominal pain that did not radiate or remit. He reported no nausea, vomiting, diarrhea, fevers, chills, weight loss, or night sweats. He had a normal bowel movement the previous day. The patient had never undergone a colonoscopy. Initially, the patient had stable vital signs, a tender abdomen without rebound or guarding, and unremarkable laboratory test results. A computed tomography (CT) scan of his abdomen and pelvis showed mild dilation of the ascending, transverse, and proximal descending colon with a possible “transition point concerning for stricture/mass or physiologic peristalsis.” The patient was admitted to medicine service for observation, pain management, and abdominal examination. Approximately 48 hours after hospitalization, the patient’s abdomen became more distended, with increased pain and tenderness with rebound upon examination. Personnel requested surgical consultation. After the surgeons reviewed the images and examined the patient, they immediately took him to the OR and found an obstructive mass with associated perforation. The patient experienced a prolonged postoperative course with intra-abdominal infection before ultimately dying. The institution formally reviewed the case because of concerns regarding a possible delay in treatment and surgical consultation.
Approximately 75% of these intestinal obstructions are caused by adhesions from previous operations.6 The remaining obstructions result from Crohn’s disease, neoplasia, hernia (internal or abdominal wall), radiation, congenital adhesions, or other causes.6 Early on, hyperperistalsis may produce loose stools, but by the time the patient presents to the physician, diarrhea is rarely a prominent symptom. Symptoms may include abdominal distension, tenderness, oliguria, tachycardia, dry mucous membranes, anddin some casesd peritonitis. Bowel auscultation is not useful; all bowel sounds are compatible with obstruction. As the condition progresses, the obstructed bowel becomes edematous, dilated, and overgrown with bacteria. When luminal pressure exceeds capillary perfusion pressure, ischemia of the intestinal wall occurs, followed by peritonitis, perforation, and sepsis. If this process continues uninterrupted, death may result from either septic or hypovolemic shock. Initial evaluation should include assessment of blood cell counts, electrolytes, creatinine, urine output, and vital signs. Both metabolic alkalosis (from vomiting) and metabolic acidosis can be seen.1-3 Initial management is bowel rest, isotonic crystalloid solution resuscitation, serial abdominal examinations, and nasogastric tube suction (which may be omitted if the patient is not retching). The best imaging for intestinal obstruction is a CT scan of the abdomen and pelvis with IV contrast and without oral contrast.1,7-11 Plain films of the abdomen are usually not continued on page 65
DISCUSSION This case illustrates the difficulty of diagnosing a bowel obstruction from clinical features and imaging. For more than 50 years, there have been numerous failed attempts to identify predictors of strangulating obstruction based on symptoms, signs, laboratory tests, and imaging characteristics.1-3 There is simply no good predictor, or combination of predictors, that allows for accurate identification of a bowel obstruction. This fact is disheartening, given that intestinal obstruction is one of the most common surgical emergencies in the United States, leading to more than 300,000 operations per year.4,5
This content is adapted from AHRQ WebM&M (Morbidity & Mortality Rounds on the Web) with permission from the Agency for Healthcare Research and Quality. The original commentary was written by Jonathan Carter, MD, and was adapted for this article by Nancy J. Girard, PhD, RN, FAAN, consultant/owner, Nurse Collaborations, Boerne, TX. (Citation: Carter J. An obstructed view. AHRQ WebM&M [serial online]. https://psnet.ahrq.gov/webmm/ case/361/an-obstructed-view. Published October 2015. Accessed January 30, 2017.) Dr Girard has no declared affiliation that could be perceived as posing a potential conflict of interest in the publication of this article. http://dx.doi.org/10.1016/j.aorn.2017.03.013 ª AORN, Inc, 2017
92 j AORN Journal
www.aornjournal.org
July 2017, Vol. 106, No. 1
Perioperative Grand Rounds
continued from page 92
PERIOPERATIVE POINTS
helpful. Classic findings for intestinal obstruction are a proximally dilated bowel (less than 3 cm) with air-fluid levels terminating in a transition point, followed by a decompressed bowel and colon. Findings that raise concern for strangulation are ascites, a thick-walled bowel, segmental mesenteric fluid, free air, mesenteric stranding, decreased mucosal enhancement, pneumatosis, and a closed loop (ie, a dilated bowel pinched at both ends).
Strangulating intestinal obstruction remains challenging to diagnose. Obstructions in patients without histories of abdominal surgery are uncommon and warrant early surgical evaluation. Obstructions that do not resolve within 72 hours generally require surgery. For any patient admitted with a possible urgent bowel obstruction, communication with the OR should occur immediately upon diagnosis to prepare staffing and surgical space.
After establishing an intestinal obstruction diagnosis, personnel should determine whether any features of strangulation are present. Symptoms may include fever, tachycardia, leukocytosis, constant pain (as opposed to colicky pain), and peritonitis. Unfortunately, even these classic signs are of poor predictive value. One multivariate analysis showed that decreased mucosal enhancement was the only independent predictor of strangulating obstruction.1 Decreased mucosal enhancement on CT is a powerful predictor of strangulating obstruction anddwhen accompanied by concerning CT findings, as noted abovedis an indication for surgical exploration. In this case, several features warranted early surgical evaluation. First, the patient had not undergone a previous abdominal operation, making adhesion an unlikely culprit. Of the remaining causes of obstruction, most require an operation. Second, there is a strong argument for early laparoscopic evaluation in this setting, both to confirm the diagnosis and to treat the offending lesion that may be found with laparoscopy.12 Third, the radiographic reporting deserves scrutiny: Was the transition point in the small bowel or colon? Were any concerning features of strangulation present? Is neoplasia suspected? In this case, it is unlikely that the patient progressed to perforation within 48 hours without any subtle warning signs on the index CT; these signs may not have appeared in the dictated report. As this case illustrates, a patient can have strangulated or obstructed bowel with no clinical or radiographic predictors, so time should also be considered a diagnostic test. Using close observation and serial examinations, a physician can better understand the trajectory of the patient’s illness. A practice pearl: “Obstructions destined to resolve nonoperatively generally do so within 72 hours. A patient who is getting sicker needs urgent surgical evaluation.”
www.aornjournal.org
References 1. Jancelewicz T, Vu LT, Shawo AE, Yeh B, Gasper WJ, Harris HW. Predicting strangulated small bowel obstruction: an old problem revisited. J Gastrointest Surg. 2009;13(1):93-99. 2. Sarr MG, Bulkley GB, Zuidema GD. Preoperative recognition of intestinal strangulation obstruction. Prospective evaluation of diagnostic capability. Am J Surg. 1983;145(1):176-182. 3. Silen W, Hein MF, Goldman L. Strangulation obstruction of the small intestine. Arch Surg. July 1962;85:121-129. 4. Scott FI, Osterman MT, Mahmoud NN, Lewis JD. Secular trends in small-bowel obstruction and adhesiolysis in the United States: 1988e2007. Am J Surg. 2012;204(3):315-320. 5. Ray NF, Denton WG, Thamer M, Henderson SC, Perry S. Abdominal adhesiolysis: inpatient care and expenditures in the United States in 1994. J Am Coll Surg. 1998;186(1):1-9. 6. Miller G, Boman J, Shrier I, Gordon PH. Etiology of small bowel obstruction. Am J Surg. 2000;180(1):33-36. 7. Zalcman M, Sy M, Donckier V, Closset J, Gansbeke DV. Helical CT signs in the diagnosis of intestinal ischemia in small-bowel obstruction. AJR Am J Roentgenol. 2000;175(6):1601-1607. 8. Sheedy SP, Earnest FIV, Fletcher JG, Fidler JL, Hoskin TL. CT of small-bowel ischemia associated with obstruction in emergency department patients: diagnostic performance evaluation. Radiology. 2006;241(3):729-736. 9. Kim JH, Ha HK, Kim JK, et al. Usefulness of known computed tomography and clinical criteria for diagnosing strangulation in smallbowel obstruction: analysis of true and false interpretation groups in computed tomography. World J Surg. 2004;28(1):63-68. 10. Ha HK, Kim JS, Lee MS, et al. Differentiation of simple and strangulated small-bowel obstructions: usefulness of known CT criteria. Radiology. 1997;204(2):507-512. 11. Donckier V, Closset J, Van Gansbeke D, et al. Contribution of computed tomography to decision making in the management of adhesive small bowel obstruction. Br J Surg. 1998;85(8):1071-1074. 12. Franklin ME Jr, Gonzalez JJ Jr, Miter DB, Glass JL, Paulson D. Laparoscopic diagnosis and treatment of intestinal obstruction. Surg Endosc. 2004;18(1):26-30.
AORN Journal j 65