Critical Care Medicine

Critical Care of the Abdominal Surgery Patient; Intra-peritoneal Surgery; Emergency General Surgery; Elective General Surgery

Abdominal Surgery

Synonyms

Intra-peritoneal surgery; Emergency General Surgery; Elective General Surgery

This list of associated conditions is protean and covers surgery on all of the intra-, retro-, and extra-peritoneal organs as well as the abdominal wall.

1. Description of the problem

There are a host of safe and effective methods of managing the abdominal surgery patient who needs critical care. In general, patients who have undergone abdominal surgery and who need critical care do so for the management of sepsis, effective circulating volume, metabolic acidosis, compartment pressure-volume relationships, mean arterial pressure with regard to bleeding, work of breathing, hypoxia, hypercarbia, and mechanical ventilation. While there are a host of associated conditions that are concomitantly managed in these patients, the above reasons are the predominant indications for critical care.

Clinical features

Clinical features of the abdominal surgery patient will vary with the primary diagnosis. Nonetheless, such patients may be categorized by whether or not they require mechanical ventilation, have an open body cavity, or have severe sepsis or septic shock. All of the other associated conditions depend on the three main categorizations listed above. Virtually all of the patients require initial fluid resuscitation. Trauma patients who may require massive resuscitation and massive transfusion will be addressed in other chapters.

Key management points

1. Ensure adequate resuscitation.

2. Provide maintenance fluid in addition to resuscitation fluids; these are generally two different prescriptions.

3. Address the need for antimicrobial management.

4. Provide prophylactic measures targeted to reduce ICU-related complications.

5. Communicate directly with the family to establish realistic goals of care; include the primary surgical team and the nursing staff in these discussions.

6. Actively manage associated conditions and comorbidities.

7. Address nutritional support.

8. Actively search for known complications of the surgery that was performed as well as known complications of therapy prescribed in the ICU.

2. Emergency Management

Emergency management and stabilization of the abdominal surgery patient takes two general paths: 1) surgery as the means to stabilization, and 2) ICU care before surgery to stabilize the patient. Two important conditions should not undergo ICU stabilization prior to operative intervention: occlusive mesenteric ischemia and necrotizing soft tissue infection. These two general surgery conditions require surgery to control the underlying process and one cannot get ahead of the disease process with resuscitation prior to operation. Virtually all other conditions have the potential to benefit from a period of ICU management prior to definitive operation as the vast majority of these are related to obstructive, inflammatory or infective processes.

Of course, hemorrhage from a ruptured abdominal aortic aneurysm should proceed to the OR and not to the ICU. Vascular surgery processes such as limb-threatening ischemia, extremity compartment syndrome, and vascular hemorrhage need emergent management in either the OR or the angiography suite. As vascular diagnosis and management has become increasingly complex, often divergent between centers, and increasingly non-operative in favor of catheter-based procedures, the remainder of this chapter will focus on the general surgery patient who has undergone an abdominal procedure.

Management points not to be missed

Checklists are not unique to the patient who has undergone abdominal surgery. However, abdominal surgery patients requiring critical care management should be assessed on a daily basis for suitability for liberation from mechanical ventilation, suitability for enteral nutrition, ability to participate in physical therapy, and complications unique to their surgery or the care they have received in the ICU. Most notably, surgical site infection, anastomotic leak, hemorrhage, wound dehiscence, and abdominal compartment syndrome head the list of elements for which one should be assessing on at least a daily basis.

Drugs and dosages

There are no medications that are unique to the abdominal surgery patient. While there is an identified desire for a safe promotility agent, in particular to counteract colonic dysmotility that follows in the wake of opioid analgesia, no consistently and reliably effective agent is currently available. Instead, metoclopramide (10 mg IV/PO q 6; 50% dose reduction in the elderly or those with impaired renal function) and erythromycin ethyl-succinate (500 mg PO q 6 hours) serve as reasonable alternatives. EES may have ideal use in those with diabetic gastroparesis as well.

3. Diagnosis

Patients with abdominal surgery may have undergone a typical laparotomy or increasingly a complex laparoscopic procedure. The complications and management generally differ little between the two, with the exceptions that the laparoscopically managed patient will have less evaporative loss and less operative site pain.

The diagnostic approach to the abdominal surgery patient requiring critical care will vary depending on the pre-test probability of a given diagnosis. Because of the vast number of potential complications, it is perhaps more useful to identify general principles and certain exclusionary elements that will guide diagnostic test selection.

In general, patients who have undergone abdominal surgery have incisions that need to be inspected on a daily basis as a clue to surgical site infection. Patients who have undergone natural orifice surgery extremely rarely need critical care; if so, they do not have incisions that are inspectable. Abdominal surgery patients are subject to the same kinds of complications as any ICU patient (i.e., deep vein thrombosis and embolism, myocardial ischemia, organ failure, pressure ulceration, etc.) and should not be considered any differently. On the other hand, abdominal surgery patients are at higher risk for wound failure (direct inspection) and abdominal compartment syndrome (bladder pressure monitoring). Like any other ICU patient, evidence of sepsis should be evaluated with blood, urine and sputum cultures, and a careful inspection of invasive catheter sites.

Since the source of infection is often within the operative site, certain caveats need to be kept in mind. CT scanning to evaluate for leak or abscess is difficult to interpret earlier than the 5th post-operative day due to post-surgical inflammatory change and the certain presence of free intra-peritoneal gas from the operation. If an intra-abdominal process is suspected earlier than the 5th post-operative day, re-exploration is often the best approach. Alternatively, a diagnostic peritoneal lavage may be undertaken looking for a high WBC count, high amylase or lipase, bile, or GI luminal contents. See Figure 1, Figure 2, Figure 3, Figure 4, Figure 5, Figure 6, Figure 7, Figure 8, Figure 9.

Figure 1.

Intra-abdominal HTN may arise from distended colon. Excessive unrelieved distention may induce ischemia, as in this colon.

Figure 2.

Embolic ischemia may occur without distention but may be accompanied by bacteremia, acidosis and septic shock.

Figure 3.

Longstanding SBO results in colonic collapse, SI atony and feeding intolerance. SI intubation will optimally decompress the SI and serve as a conduit for luminal nutrition.

Figure 4.

Dense adhesive SBO may require resection of thinned segments, leading to bactermia, SI distention and the need to leave the abdomen open to accommodate the post-resuscitation visceral edema.

Figure 5.

Hypercoagulability after a simple procedure such as an appendectomy may lead to mesenteric venous thrombosis. ICU care should address the enhanced clotting while awaiting the second-look laparotomy.

Figure 6.

Uncloseable patients may be managed with Vicryl mesh followed by a split-thickness skin graft after there is sufficient granulation tissue.

Figure 7.

Tertiary peritonitis represents host defense failure and requires prolonged management with an open anterior abdominal wall to reduce the bacterial burden with repeated washouts.

Figure 8.

Split-thickness skin grafts are not very strong. Vigorous coughing in a patient with a small bowel ileus led to tearing of the skin graft and the underlying adherent small bowel, leading to an enteroatmospheric fistula.

Figure 9.

Anastomoses that are not readily covered with vascularized tissue are subject to enteroatmospheric fistula formation. Alternatively, post-op necrotizing soft tissue infection that requires abdominal wall resection presents a similar risk to the patient with enteric anastomoses.

Pathophysiology

The pathophysiology of abdominal surgery is complex yet straightforward unless there are complications. Operations within the peritoneal space, the retroperitoneum or the extra-peritoneal space all share the following core elements: inflammation from tissue manipulation, capillary leak from tissue inflammation leading to tissue edema, activation of the renin-angiotensin-aldosterone pathway leading to an increase in anti-diuretic hormone and salt and water retention. Open procedures are also characterized by evaporative losses that are not evident during laparoscopic procedures.

It is important to ensure that effective circulating volume is restored if it has not been already addressed in the OR. One must compare the patient's intake to the losses, and judge that fluid balance against objective indicators of perfusion adequacy. This evaluation is often aided by objective measures of flow-based cardiac performance, and many devices are available to aid the intensivist; device selection is often institution- or unit-specific and beyond the scope of this chapter. However, normotonic crystalloid fluids or colloid preparations are ideal for repairing effective circulating volume deficits. The selection of fluid is often a matter of local practice. However, whether one uses crystalloids, and especially when using colloids that do not provide free water, the patient must also receive maintenance fluid to address the need for glucose and to provide free water. Colloid resuscitation without free water will lead to hyperoncoticity, acute kidney injury, and ultimately acute renal failure.

While there is nothing that one can do to modify capillary leak, one can evaluate for its sequelae. In this patient population, capillary leak often leads to extravascular lung water, exacerbates atelectasis, promotes ascites and visceral edema, and predisposes to intra-abdominal hypertension and the abdominal compartment syndrome. It is important to monitor for each of these and adjust therapy accordingly.

Generally, the abdominal surgery patient should have a fluid requirement greater than maintenance needs on post-op day 1 (POD), 75-100% of maintenance on POD2, and 50-75% of maintenance on POD3. These patients are expected to diurese on POD3 as well; such spontaneous diuresis is generally regarded as a sign of overall well-being. The critically ill abdominal surgery patient who requires > 48 hours of critical care may not follow this clinical path. However, the vast majority of patients who are in the ICU for monitoring, but who are not critically ill, do follow this path and should have their IVF adjusted accordingly. Failure to do so may lead to iatrogenic fluid overload, cardiac dysrhythmia, myocardial ischemia, increased work of breathing, airway control, mechanical ventilation and readmission.

Since infection is a major cause of post-operative morbidity, a brief discussion of infection-relevant issues is in order. Appropriate delivery of prophylactic antibiotic agents has been shown to reduce post-operative surgical site infection rates. However, many critically ill abdominal surgery patients require critical care for intra-abdominal sepsis and are receiving therapeutic antimicrobial agents. Part of source control requires drainage of abscesses and control of the etiology of the infection. However, resuscitation (see above) is critical in delivering oxygen and white blood cells to sites of infection as well. Hematomas do not have an independent blood supply and one cannot get antibiotics into these collections. Therefore, evacuation of hematomas is important in reducing the bacterial burden in an infected peritoneal space.

Since the concept of damage control has also been applied to emergency general surgery, it deserves specific comment. Borrowed from the well-articulated management principles of the in extremis trauma patient, damage control addresses vascular hemorrhage and GI tract contamination as the therapeutic goals for the initial operation. ICU resuscitation, normalization of metabolic abnormalities, coagulopathy and temperature is followed by a planned reexploration at 24-48 hours. This approach is equally well suited to the emergency general surgery patient with septic shock from an intra-abdominal source. These patients generally undergo intestinal resection or patch repair, may be left in discontinuity, may be packed to help control microvascular hemorrhage, and are left with a temporary abdominal wall closure to facilitate abdominal reentry.

If the anterior abdominal wall is not closable, the patient is at high risk for anastomotic leak and enteroatmospheric fistula formation; it is clear that anastomoses not covered by vascularized tissue are more prone to fistula formation. Such fistulae are potentially devastating and are certainly challenging to manage as they often preclude luminal nutrition and engender accelerated protein losses to the external environment. Therefore, all efforts should be made to reasonably achieve abdominal wall closure using native tissue. A component separation of parts technique is often particularly useful in this patient population. The role of biologic mesh as an underlay in this patient population (contaminated abdominal space) is being clarified but there are not enough data to make a firm recommendation at the moment.

Epidemiology

Patients with abdominal surgery and its complications generally represent > 50% of the patient population in a tertiary or quaternary care hospital's surgical ICU. The proportion will differ, of course, in other facilities, and especially if the ICU patient population is a mixed medical-surgical mix. Specific complications will also vary based upon patient acuity and the kind of procedures being performed.

Special considerations for nursing and allied health professionals.

Nutritional support of the abdominal surgery patient requiring critical care may generally be undertaken using GI luminal access. It is the rare patient who requires hyperalimentation for nutritional management. In fact, if a patient arrives in the ICU and has a jejunal access catheter, trophic tube feeds may be initiated as soon as it has been established that the patient is not hypoperfused; either direct jejunal catheter insertion, trans-gastric jejunal catheter insertion or naso/oro-jejunal catheter insertion will suffice for enteral access.

Patients may also be fed into the stomach, but gastric ileus generally persists after general anesthesia, while jejunal peristalsis readily occurs. Thus, gastric feeding may be delayed while awaiting return of normal peristaltic activity in comparison to jejunal feeding. Hyperalimentation is generally reserved for those with a prolonged ileus, tube feed intolerance, high-volume enterocutaneous fistulae and enteroatmospheric fistulae. Critically ill patients with Crohn's disease complications may also benefit from hyperalimentation as well.

Many abdominal surgery patients require repeated operations and are receiving enteral feeds. There is no need to hold jejunal tube feeds after 12MN in preparation for repeated operation if the patient remains intubated and a GI tract anastomosis is not planned. While holding tube feeds is a common practice, there is no evidence that it is required for those with an indwelling endotracheal tube; the authors simply hold the tube feeds on the way to the OR, or turn them off immediately prior to the start of the procedure in the ICU (including intra-abdominal procedures in those with an open abdomen).

What's the evidence?

Emergency General Surgery/Acute Care surgery Critical Care

Tisherman, SA, Ivy, ME, Frangos, SG, Kirton, OC. "Acute care surgery survey: opinions of surgeons about a new training paradigm". Arch Surg. vol. 146. 2011. pp. 101-6.

Napolitano, LM, Fulda, GJ, Davis, KA, Ashley, DW, Friese, R, Van Way, CW, Meredith, JW, Fabian, TC, Jurkovich, GJ, Peitzman, AB. "Challenging issues in surgical critical care, trauma, and acute care surgery: a report from the Critical Care Committee of the American Association for the Surgery of Trauma". Journal of Trauma-Injury Infection & Critical Care. vol. 69. 2010. pp. 1619-33.

Galante, JM, Phan, HH, Wisner, DH. "Trauma surgery to acute care surgery: defining the paradigm shift". Journal of Trauma-Injury Infection & Critical Care. vol. 68. 2010. pp. 1024-31.

Lees, N, Hamilton, M, Rhodes, A. " Clinical review: Goal-directed therapy in high risk surgical patients". Critical Care (London, England). vol. 13. 2009. pp. 231.

Velmahos, GC, Alam, HB. "Advances in surgical critical care". Current Problems in Surgery. vol. 45. 2008. pp. 453-516.

Cohn, SM, Price, MA, Stewart, RM, Corneille, MG, Myers, JG, McCarthy, J, Jonas, RB, Hargis, SM, Dent, DL. "Surgical critical care and private practice surgeons: a different world out there". Journal of the American College of Surgeons. vol. 206. 2008. pp. 419-25.

Kozar, RA, Shackford, SR, Cocanour, CS. "Challenges to the care of the critically ill: novel staffing paradigms". Journal of Trauma-Injury Infection & Critical Care. vol. 64. 2008. pp. 366-70; discussion 370-3.

Aarts, MA, Granton, J, Cook, DJ, Bohnen, JM, Marshall, JC. "Empiric antimicrobial therapy in critical illness: results of a surgical infection society survey". Surgical Infections. vol. 8. 2007. pp. 329-36.

Penkoske, PA, Buchman, TG. "The relationship between the surgeon and the intensivist in the surgical intensive care unit". Surg Clin North Am. vol. 86. 2006. pp. 1351-7.

Sise, MJ, Sise, CB, Sack, DI, Goerhing, M. "Surgeons' attitudes about communicating with patients and their families". Current Surgery. vol. 63. 2006. pp. 213-8.

Kaplan, LJ, Frankel, HL, Hojman, H, Portereiko, J, Rabinovici, R. "What price for general surgery". Journal of Trauma-Injury Infection & Critical Care. vol. 59. 2005. pp. 394-5.

Eachempati, SR, Miller, FG, Fins, JJ. "The surgical intensivist as mediator of end-of-life issues in the care of critically ill patients". Journal of the American College of Surgeons. vol. 197. 2003. pp. 853-4.

Arbabi, S, Jurkovich, GJ, Rivara, FP, Nathens, AB, Moore, M, Demarest, GB, Maier, RV. "Patient outcomes in academic medical centers: influence of fellowship programs and in-house on-call attending surgeon". Archives of Surgery. vol. 138. 2003. pp. 47-51; discussion 51.

Intra-abdominal Hypertension/Abdominal Compartment Syndrome

De Waele, JJ, De Laet, I, Kirkpatrick, AW, Hoste, E. "Intra-abdominal Hypertension and Abdominal Compartment Syndrome". American Journal of Kidney Diseases. vol. 57. 2011. pp. 159-69.

Lui, F, Sangosanya, A, Kaplan, LJ, Siegel, M. "Abdominal Compartment Syndrome: Clinical Aspects and Monitoring". Critical Care Clinics. Elsevier. 2007.

Betro, G, Kaplan, LJ, Kellum, Ja, Ronco, C, Bellomo, R. "Abdominal Compartment Syndrome". In Critical Care Nephrology. 2009. pp. 345-51.

Ventilator-Associated Pneumonia/Infection Control

Coppadoro, A, Berra, L, Bigatello, LM. "Modifying endotracheal tubes to prevent ventilator-associated pneumonia". Current Opinion in Infectious Diseases. vol. 24. 2011. pp. 157-62.

Lorente, L, Blot, S, Rello, J. "New issues and controversies in the prevention of ventilator-associated pneumonia". American Journal of Respiratory & Critical Care Medicine. vol. 182. 2010. pp. 870-6.

Woeltje, KF, McMullen, KM. "Critical Care Medicine". Developing information technology for infection prevention surveillance. vol. 38. 2010. pp. S399-404.

Jones, RN. "Microbial etiologies of hospital-acquired bacterial pneumonia and ventilator-associated bacterial pneumonia". Clinical Infectious Diseases. vol. 51. 2010. pp. S81-7.

Nutrition Support

Marik, PE, Zaloga, GP. "Immunonutrition in high-risk surgical patients: a systematic review and analysis of the literature". Jpen: Journal of Parenteral & Enteral Nutrition. vol. 34. 2010. pp. 378-86.

Cerantola, Y, Hubner, M, Grass, F, Demartines, N, Schafer, M. "Immunonutrition in gastrointestinal surgery". British Journal of Surgery. vol. 98. 2011. pp. 37-48.

Mizock, BA. "Immunonutrition and critical illness: an update". Nutrition.. vol. 26. 2010. pp. 701-7.

Stahel, PF, Flierl, MA, Moore, EE. ""Metabolic staging" after major trauma - a guide for clinical decision making". Scandinavian Journal of Trauma, Resuscitation & Emergency Medicine. vol. 18. 2010. pp. 34.

Acute Kidney Injury/Acute Renal Failure/Fluids and Electrolytes

Bagshaw, SM, Wald, R. " Acute kidney injury in 2010: Advances in diagnosis and estimating disease prognosis". Nature Reviews Nephrology. vol. 7. 2011. pp. 70-1.

Kaplan, LJ, Kellum, JA. "Fluids, pH, ions and electrolytes". Current Opinion in Critical Care. vol. 16. 2010. pp. 323-31.

Srisawat, N, Lawsin, L, Uchino, S, Bellomo, R, Kellum, JA. "BEST Kidney Investigators. Cost of acute renal replacement therapy in the intensive care unit: results from The Beginning and Ending Supportive Therapy for the Kidney (BEST Kidney) study". Critical Care (London, England). vol. 14. 2010. pp. R46.

Srisawat, N, Murugan, R, Wen, X, Singbartl, K, Clermont, G, Eiam-Ong, S, Kellum, JA. "Recovery from acute kidney injury: determinants and predictors". Contributions to Nephrology. vol. 165. 2010. pp. 284-91.

Himmelfarb, J, Joannidis, M, Molitoris, B, Schietz, M, Okusa, MD, Warnock, D, Laghi, F, Goldstein, SL, Prielipp, R, Parikh, CR, Pannu, N, Lobo, SM, Shah, S, D'Intini, V, Kellum, JA. "Evaluation and initial management of acute kidney injury". Clinical Journal of The American Society of Nephrology: CJASN. vol. 3. 2008. pp. 962-7.

Kellum, JA, Cerda, J, Kaplan, LJ, Nadim, MK, Palevsky, PM. "Fluids for prevention and management of acute kidney injury". International Journal of Artificial Organs. vol. 31. 2008 Feb. pp. 96-110.

Metabolic Acidosis/Inflammatory Molecules/Sepsis

Noritomi, DT, Soriano, FG, Kellum, JA, Cappi, SB, Biselli, PJ, Liborio, AB, Park, M. "Metabolic acidosis in patients with severe sepsis and septic shock: a longitudinal quantitative study". Critical Care Medicine. vol. 37. 2009. pp. 2733-9.

Yende, S, D'Angelo, G, Kellum, JA, Weissfeld, L, Fine, J, Welch, RD, Kong, L, Carter, M, Angus, DC. "GenIMS Investigators. Inflammatory markers at hospital discharge predict subsequent mortality after pneumonia and sepsis". American Journal of Respiratory & Critical Care Medicine. vol. 177. 2008 Jun 1. pp. 1242-7.

Kellum, JA, Song, M, Almasri, E. "Hyperchloremic acidosis increases circulating inflammatory molecules in experimental sepsis". Chest. vol. 130. 2006 Oct. pp. 962-7.

Gunnerson, KJ, Saul, M, He, S, Kellum, JA. "Lactate versus non-lactate metabolic acidosis: a retrospective outcome evaluation of critically ill patients". Critical Care (London, England). vol. 10. 2006 Feb. pp. R22.

Kellum, JA, Song, M, Li, J. "Science review: extracellular acidosis and the immune response: clinical and physiologic implications". Critical Care (London, England). vol. 8. 2004 Oct. pp. 331-6.

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