Sabiston Textbook of Surgery, 19th Edition. Sample Chapter 13


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Sabiston Textbook of Surgery, 19th Edition. Sample Chapter 13

  1. 1. Chapter 13 SurgiCal CompliCationS Mahmoud N. Kulaylat and Merril T. Dayton operations can be performed in a purely elective fashion, whereas surgical wound complications others must be done in an urgent fashion. Occasionally, the complications of thermal regulation surgeon will require that the patient lose weight before the respiratory complications operation to enhance the likelihood of a successful outcome. cardiac complications At times, a wise surgeon will request preoperative consultation renal and urinary tract complications from a cardiologist or pulmonary specialist to make certain that endocrine gland dysfunction the patient will be able to tolerate the stress of a particular gastrointestinal complications procedure. hepatobiliary complications Once the operation has begun, the surgeon can do much neurologic complications to influence the postoperative outcome. Surgeons must handle ear, nose, and throat complications tissues gently, dissect meticulously, and honor tissue planes. Performing the technical portions of the operation carefully will lower the risk for a significant complication. At all costs, sur­ geons must avoid the temptation to rush, cut corners, or accept Surgical complications remain a frustrating and difficult aspect marginal technical results. Similarly, the judicious use of anti­ of the operative treatment of patients. Regardless of how techni­ biotics and other preoperative medications can influence the cally gifted and capable surgeons are, all will have to deal with outcome. For a seriously ill patient, adequate resuscitation may complications that occur after operative procedures. The cost of be necessary to optimize the patient before giving a general surgical complications in the United States runs into millions of anesthetic. dollars; in addition, such complications are associated with lost Once the operation is completed, compulsive postoperative work productivity, disruption of family life, and stress to employ­ surveillance is mandatory. Thorough and careful rounding on ers and society in general. Frequently, the functional results of patients on a regular basis postoperatively gives the operating the operation are compromised by complications; in some surgeon an opportunity to be vigilant and seek postoperative cases the patient never recovers to the preoperative level of func­ complications at an early stage, when they can be most effec­ tion. The most significant and difficult part of complications is tively addressed. During this process, the surgeon will carefully the suffering borne by a patient who enters the hospital antici­ check all wounds, evaluate intake and output, check temperature pating an uneventful operation but is left suffering and compro­ profiles, ascertain what the patient’s activity levels have been, mised by the complication. evaluate nutritional status, and check pain levels. Over years of Complications can occur for a variety of reasons. A surgeon experience, the clinician can begin to assess these parameters and can perform a technically sound operation in a patient who is detect deviations from the normal postoperative course. Expedi­ severely compromised by the disease process and still have a tious response to a complication makes the difference between complication. Similarly, a surgeon who is sloppy or careless or a brief, inconvenient complication and a devastating, disabling hurries through an operation can make technical errors that one. In summary, a wise surgeon will deal with complications account for the operative complications. Finally, the patient can quickly, thoroughly, and appropriately. be healthy nutritionally, have an operation performed meticu­ lously, and yet suffer a complication because of the nature of the disease. The possibility of postoperative complications Surgical Wound complicationS remains part of every surgeon’s mental preparation for a difficult operation. Seroma Surgeons can do much to avoid complications by careful preoperative screening. When the surgeon sees the surgical can­ Causes didate for the first time, a host of questions come to mind, such A seroma is a collection of liquefied fat, serum, and lymphatic as the nutritional status of the patient and the health of the heart fluid under the incision. The fluid is usually clear, yellow, and and lungs. The surgeon will make a decision regarding perform­ somewhat viscous and is found in the subcutaneous layer of the ing the appropriate operation for the known disease. Similarly, skin. Seromas represent the most benign complication after an the timing of the operation is often an important issue. Some operative procedure and are particularly likely to occur when K2 13-1Townsend_Chapter 13_main.indd 1 6/10/2011 12:36:18 PM
  2. 2. 13-2  section ii  PerioPerative ManageMent large skin flaps are developed in the course of the operation, as or associated with drainage of dark red fluid out of the fresh is often seen with mastectomy, axillary dissection, groin dissec­ wound. tion, and large ventral hernias or when a prosthetic mesh Hematoma formation is prevented preoperatively by cor­ (polytetrafluoroethylene) is used in the repair of a ventral hernia. recting any clotting abnormalities and discontinuing medi­ cations that alter coagulation. Antiplatelet medications and presentation and management anticoagulants may be given to patients undergoing procedures A seroma usually manifests as a localized and well­circumscribed for a variety of reasons. Clopidogrel is given after implantation swelling, pressure or discomfort, and occasional drainage of clear of a coronary stent, ASA is given for the treatment of coronary liquid from the immature surgical wound. Prevention of seroma artery disease (CAD) and stroke, and VKA is given after implan­ formation may be achieved with placement of suction drains tation of a mechanical mitral valve for atrial fibrillation, venous under the flaps. Their premature removal often results in large thromboembolism, and hypercoagulable states. These medica­ seromas that will require aspiration under sterile conditions, tions must be temporarily discontinued before surgery. There are followed by placement of a pressure dressing. A seroma that no specific studies that have addressed the issue of timing of reaccumulates after at least two aspirations is evacuated by discontinuation of such medications. opening the incision and packing the wound with saline­ One must balance the risk of significant bleeding caused moistened gauze to allow healing by secondary intention. In the by uncorrected medication­induced coagulopathy and the risk presence of synthetic mesh, open drainage is best performed in of thromboembolic events after discontinuation of therapy. The the operating room, the incision is best closed to avoid exposure risk of bleeding varies with the type of surgery or procedure and infection of the mesh, and suction drains are placed. An and adequacy of hemostasis; the risk of thromboembolism infected seroma is also treated with open drainage. The presence depends on the indication for antithrombotic therapy and pres­ of synthetic mesh in these cases will prevent the wound from ence of comorbid conditions.1 In patients at high risk for healing. Management of the mesh depends on the severity and thromboembolism (e.g., those with a mechanical mitral valve extent of infection. In the absence of severe sepsis and spreading or older generation aortic valve prosthesis, venous thromboem­ cellulitis and the presence of localized infection, the mesh can bolism within 3 months, severe thrombophilia, recent atrial be left in situ and removed at a later date when the acute infec­ fibrillation [within 6 months], stroke or transient ischemic tious process has resolved. Otherwise, the mesh must be removed attack who are scheduled to undergo an elective major surgical and the wound managed with open wound care. procedure involving a body cavity), the VKA must be discon­ tinued 4 to 5 days before surgery to allow the international Hematoma normalized ratio (INR) to be lower than 1.5. In patients whose INR is still elevated (>1.5), low­dose vitamin K (1 to 2 mg) is 1 Causes given orally. Patients are then given bridging anticoagulation— A hematoma is an abnormal collection of blood, usually in the that is, a therapeutic dose of rapidly acting anticoagulant, intra­ subcutaneous layer of a recent incision or in a potential space in venous (IV) UFH or to LMWH. Those receiving IV UFH the abdominal cavity after extirpation of an organ (e.g., splenic (half­life, 45 minutes) can have the medication discontinued 4 fossa hematoma after splenectomy or pelvic hematoma after hours before surgery and those receiving therapeutic dose proctectomy). Hematomas are more worrisome than seromas LMWH SC (variable half­life) 16 to 24 hours before surgery. because of the potential for secondary infection. Hematoma VKA is then resumed 12 to 24 hours after surgery (takes 2 to 3 formation is related to inadequate hemostasis, depletion of clot­ days for anticoagulant effect to begin after start of VKA) and ting factors, or the presence of coagulopathy. A host of disease when there is adequate hemostasis. In patients at high risk of processes can contribute to coagulopathy, including myelopro­ bleeding (major surgery or high bleeding risk surgery) for liferative disorders, liver disease, renal failure, sepsis, clotting whom postoperative therapeutic LMWH or UFH is planned, factor deficiencies, and medications. Medications most com­ initiation of therapy is delayed for 48 to 72 hours, low­dose monly associated with coagulopathy are antiplatelet drugs, such LMWH or UFH is administered, or the therapy is completely as acetylsalicylic acid (ASA, aspirin), clopidogrel, ticlopidine, avoided. Patients at low risk for thromboembolism do not eptifibatide, and abciximab, and anticoagulants, such as ultra­ require heparin therapy after discontinuation of the VKA. fractionated heparin (UFH), low­molecular­weight heparin Patients on ASA or clopidogrel must have the medication with­ (LMWH [e.g., enoxaparin, dalteparin sodium, tinzaparin]), and held 6 to 7 days before surgery; otherwise, the surgery must be vitamin K antagonist (VKA [e.g., warfarin sodium]). delayed until the patient has completed the course of treat­ ment. Antiplatelet therapy is resumed approximately 24 hours presentation and management after surgery. In patients with a bare metal coronary stent who The clinical manifestations of a hematoma may vary with its size, require surgery within 6 weeks of stent placement, ASA and location, and presence of infection. A hematoma may manifest clopidogrel are continued in the perioperative period. In as an expanding, unsightly swelling and/or pain in the area of a patients who are receiving VKAs and require urgent surgery, surgical incision. In the neck, a large hematoma may cause immediate reversal of anticoagulant effect requires transfusion compromise of the airway; in the retroperitoneum, it may cause with fresh­frozen plasma or other prothrombin concentrate and a paralytic ileus, anemia, and ongoing bleeding caused by local low­dose IV or oral vitamin K. During surgery, adequate hemo­ consumptive coagulopathy; and, in the extremity and abdomi­ stasis must be achieved with ligature, electrocautery, fibrin glue, nal cavity, it may result in compartment syndrome. On physical or topical bovine thrombin before closure. Closed suction examination, the hematoma appears as a localized soft swelling drainage systems are placed in large potential spaces and with purplish blue discoloration of the overlying skin. The swell­ removed postoperatively when the output is not bloody andK2 ing varies from small to large and may be tender to palpation scant. Townsend_Chapter 13_main.indd 2 6/10/2011 12:36:18 PM
  3. 3. Surgical coMPlicationS  chapter 13  13-3 Evaluation of a patient with a hematoma, especially one presentation and management SeCtion ii PerioPerative ManageMent that is large and expanding, includes assessment of preexisting Acute wound failure may occur without warning and eviscera­ risk factors and coagulation parameters (e.g., prothrombin time tion makes the diagnosis obvious. A sudden, dramatic drainage [PT], activated partial prothrombin time [aPTT], INR, platelet of a relatively large volume of a clear, salmon­colored fluid count, bleeding time) and appropriate treatment. A small hema­ precedes dehiscence in 25% of patients. More often, patients toma does not require any intervention and will eventually report a ripping sensation. Probing the wound with a sterile, resorb. Most retroperitoneal hematomas can be managed by cotton­tipped applicator or gloved finger may detect a partial expectant waiting after correction of associated coagulopathy dehiscence. (platelet transfusion if bleeding time is prolonged, desmopressin Prevention of acute wound failure is largely a function of in patients who have renal failure, and fresh­frozen plasma in careful attention to technical detail during fascial closure, such patients who have an increased INR). A large or expanding as proper spacing of the suture, adequate depth of bite of the hematoma in the neck is managed in a similar fashion and best fascia, relaxation of the patient during closure, and achieving a evacuated in the operating room urgently after securing the tension­free closure. For very high­risk patients, interrupted airway if there is any respiratory compromise. Similarly, hema­ closure is often the wisest choice. Alternative methods of closure tomas detected soon after surgery, especially those developing must be selected when primary closure is not possible without under skin flaps, are best evacuated in the operating room. undue tension. Although retention sutures were used exten­ sively in the past, their use is less common today, with many acute Wound Failure (dehiscence) surgeons opting to use a synthetic mesh or bioabsorbable tissue scaffold. Causes Treatment of dehiscence depends on the extent of Acute wound failure (wound dehiscence or a burst abdomen) fascial separation and the presence of evisceration and/or refers to postoperative separation of the abdominal musculoapo­ significant intra­abdominal pathology (e.g., intestinal leak, neurotic layers. It is among the most dreaded complications peritonitis). A small dehiscence, especially in the proximal faced by surgeons and is of great concern because of the risk of aspect of an upper midline incision 10 to 12 days postoper­ evisceration, the need for some form of intervention, and the atively, can be managed conservatively with saline­moistened possibility of repeat dehiscence, surgical wound infection, and gauze packing of the wound and use of an abdominal incisional hernia formation. binder. In the event of evisceration, the eviscerated intestines Acute wound failure occurs in approximately 1% to 3% of must be covered with a sterile, saline­moistened towel and patients who undergo an abdominal operation. Dehiscence most preparations made to return to the operating room after a often develops 7 to 10 days postoperatively but may occur very short period of fluid resuscitation. Similarly, if probing anytime after surgery, from 1 to more than 20 days. A multitude of the wound reveals a large segment of the wound that is of factors may contribute to wound dehiscence (Box 13­1). open to the omentum and intestines, or if there is peritoni­ Acute wound failure is often related to technical errors in placing tis or suspicion of intestinal leak, plans to take the patient sutures too close to the edge, too far apart, or under too much back to the operating room are made. tension. Local wound complications such as hematoma and Once in the operating room, thorough exploration of the infection can also predispose to localized dehiscence. In fact, a abdominal cavity is performed to rule out the presence of a deep wound infection is one of the most common causes of septic focus or an anastomotic leak that may have predisposed localized wound separation. Increased intra­abdominal pressure to the dehiscence. Management of that infection is of critical (IAP) is often blamed for wound disruption and factors that importance before attempting to close. Management of the adversely affect wound healing are cited as contributing to the incision is a function of the condition of the fascia. When complication. In healthy patients, the rate of wound failure is technical mistakes are made and the fascia is strong and intact, similar whether closure is accomplished with a continuous or primary closure is warranted. If the fascia is infected or interrupted technique. In high­risk patients, however, continu­ necrotic, débridement is performed. The incision can then be ous closure is worrisome because suture breakage in one place closed with retention sutures; however, to avoid tension, use weakens the entire closure. of a prosthetic material may be preferred. Closure with an absorbable mesh (polyglactin or polyglycolic acid) may be preferable because the mesh is well tolerated in septic wounds Box 13-1  Factors associated With Wound Dehiscence and allows bridging the gap between the edges of the fascia without tension, prevents evisceration, and allows the underly­ technical error in fascial closure ing cause of the patient’s dehiscence to resolve. Once the emergency surgery wound has granulated, a skin graft is applied and wound intra-abdominal infection closure is achieved by advancing local tissue. This approach advanced age uniformly results in the development of a hernia, the repair of Wound infection, hematoma, and seroma which requires the subsequent removal of the skin graft and elevated intra-abdominal pressure use of a permanent prosthesis. An alternative method of obesity closure is dermabrasion of the skin graft followed by fascial chronic corticosteroid use closure using the component separation technique. Attempts Previous wound dehiscence to close the fascia under tension guarantee a repeat dehiscence Malnutrition and, in some cases, result in intra­abdominal hypertension radiation therapy and chemotherapy (IAH). The incision is left open (laparotomy), closed with a Systemic disease (uremia, diabetes mellitus) temporary closure device (open abdomen technique), closed K2Townsend_Chapter 13_main.indd 3 6/10/2011 12:36:18 PM
  4. 4. 13-4  section ii  PerioPerative ManageMent with synthetic mesh or biologic graft (acellular dermal matrix), wound (macrodeformation) and removal of extracellular fluid or closed by using negative­pressure wound therapy. (via decrease in bowel edema, evacuation of excess abdominal The open abdomen technique avoids IAH, preserves the fluid, decrease in wound size), stabilization of the wound envi­ fascia, and facilitates reaccess of the abdominal cavity. With ronment, and microdeformation of the foam­wound interface, laparotomy, the wound is allowed to heal with secondary inten­ which induces cellular proliferation and angiogenesis. The sec­ tion and/or subsequently closed with a skin graft or local or ondary effects of the vacuum­assisted closure device include regional tissue. This approach is associated with prolonged acceleration of wound healing, reduction and changes in bac­ healing time, fluid loss, and risk of complex enterocutaneous terial burden, changes in biochemistry and systemic responses, fistula formation as a result of bowel exposure, desiccation, and and improvement in wound bed preparation—increase in traumatic injury. Furthermore, definitive surgical repair to local blood perfusion and induction healing response through restore the integrity of the abdominal wall will eventually be microchemical forces.3 This approach results in successful required. A temporary closure device (vacuum pack closure) closure of the fascia in 85% of cases. However, the device is protects abdominal contents, keeps patients dry, can be quickly expensive and cumbersome to wear and may cause significant removed with increased IAP, and avoids secondary complica­ pain, cause bleeding (especially in patients on anticoagulant tions seen with laparotomy. A fenestrated, nonadherent, poly­ therapy), be associated with increased levels of certain bacteria, ethylene sheet is applied on the bowel omentum, moist surgical and be associated with evisceration and hernia formation. towels or gauze with drains are placed on top, and an iodophore­ There is also an increased incidence of intestinal fistulization impregnated adhesive dressing is placed. Continuous suction is at enterotomy sites and enteric anastomoses, and in the then applied. If the fascia cannot be closed in 7 to 10 days, the absence of anastomoses. wound is allowed to granulate and then covered with a skin graft. Surgical Site infection (Wound infection) Absorbable synthetic mesh provides wound stability and is resistant to infection. It is associated with fistula and hernia Causes formation repair, which is difficult and may require recon­ Surgical site infections (SSIs) still continue to be a significant struction of the abdominal wall. Repair with nonabsorbable problem for surgeons. Despite major improvements in antibiot­ synthetic mesh such as polypropylene, polyester, or polytetra­ ics, better anesthesia, superior instruments, earlier diagnosis of fluoroethylene (PTFE) is associated with complications that surgical problems, and improved techniques for postoperative will require removal of the mesh (e.g., abscess formation, vigilance, wound infections continue to occur. Although some dehiscence, wound sepsis, mesh extrusion, bowel fistulization). may view the problem as merely cosmetic, that view represents Although PTFE is more desirable because it is nonadherent a shallow understanding of this problem, which causes signifi­ to underlying bowel, it is expensive, does not allow skin graft­ cant patient suffering, morbidity, and even mortality, and is a ing, and is associated with chronic infections. An acellular financial burden to the health care system. Furthermore, SSIs dermal matrix (bioprosthesis) has the mechanical properties of represent a risk factor for the development of incisional hernia, a mesh for abdominal wall reconstruction and physiologic which requires surgical repair. Currently, in the United States, properties that make it resistant to contamination and/or SSIs account for almost 40% of hospital­acquired infections 3 infection. The bioprosthesis provides immediate coverage of among surgical patients. the wound and serves as mechanical support in a single­stage The surgical wound encompasses the area of the body, reconstruction of compromised surgical wounds. It is bioactive internally and externally, that involves the entire operative site. because it functions as tissue replacement or scaffold for new Wounds are thus categorized into three general categories: tissue growth; it stimulates cellular attachment, migration, 1. Superficial, which includes the skin and subcutane­ neovascularization, and repopulation of the implanted graft. ous tissue A bioprosthesis also reduce long­term complications (e.g., 2. Deep, which includes the fascia and muscle erosion, infection, chronic pain). Available acellular materials 3. Organ space, which includes the internal organs of are animal­derived (e.g., porcine intestinal submucosa, porcine the body if the operation includes that area dermis, cross­linked porcine dermal collagen) or human­ The Centers for Disease Control and Prevention has pro­ derived (e.g., cadaveric human dermis). However, the rate of posed specific criteria for the diagnosis of surgical site infections wound complications (e.g., superficial wound or graft infec­ (Box 13­2).4 tion, graft dehiscence, fistula formation, bleeding) and Surgical site infections develops as a result of contamina­ 2 hernia formation or literaxity of the abdominal wall is 25% tion of the surgical site with microorganisms. The source of these to 50%.2 microorganisms is mostly patients’ flora (endogenous source) Negative­pressure wound therapy is based on the concept when integrity of the skin and/or wall of a hollow viscus is of wound suction. A vacuum­assisted closure device is most violated. Occasionally, the source is exogenous when a break in commonly used. The device consists of a vacuum pump, can­ the surgical sterile technique occurs, thus allowing contamina­ ister with connecting tubing, open­pore foam (e.g., poly­ tion from the surgical team, equipment, implant or gloves, or urethane ether, polyvinyl alcohol foam) or gauze, and surrounding environment. The pathogens associated with a sur­ semiocclusive dressing. The device provides immediate cover­ gical site infections reflect the area that provided the inoculum age of the abdominal wound, acts as a temporary dressing, for the infection to develop. The microbiology, however, varies, does not require suturing to the fascia, minimizes IAH, and depending on the types of procedures performed in individual prevents loss of domain. Applying suction of 125 mm Hg, the practices. Gram­positive cocci account for half of the infections open­pore foam decreases in size and transmits the negative (Table 13­1)—Staphylococcus aureus (most common), coagulase­K2 pressure to surrounding tissue, leading to contraction of the negative Staphylococcus, and Enterococcus spp. S. aureus infections Townsend_Chapter 13_main.indd 4 6/10/2011 12:36:19 PM
  5. 5. Surgical coMPlicationS  chapter 13  13-5 Box 13-2  centers for Disease control and prevention  SeCtion ii PerioPerative ManageMent table  13-1  pathogens  isolated  from  postoperative  surgical  criteria for Defining a surgical site infection site infections at a University hospital Superficial incisional pathoGen percentaGe oF isoLates infection less than 30 days after surgery Staphylococcus (coagulase-negative) 25.6 involves skin and subcutaneous tissue only, plus one of the  Enterococcus (group D) 11.5 following: Staphylococcus aureus 8.7 • Purulent drainage • Diagnosis  of  superficial  surgical  site  infection  by  a  Candida albicans 6.5 surgeon Escherichia coli 6.3 • Symptoms of erythema, pain, local edema Pseudomonas aeruginosa 6.0 Deep incisional Corynebacterium 4.0 less than 30 days after surgery with no implant and soft tissue  involvement Candida (non-albicans) 3.4 infection  less  than  1  year  after  surgery  with  an  implant;  alpha-hemolytic Streptococcus 3.0 involves deep soft tissues (fascia and muscle), plus one of the  Klebsiella pneumoniae 2.8 following: vancomycin-resistant Enterococcus 2.4 • Purulent drainage from the deep space but no exten- sion into the organ space Enterobacter cloacae 2.2 • abscess  found  in  the  deep  space  on  direct  or  radio- Citrobacter spp. 2.0 logic examination or on reoperation From Weiss Ca, Statz CI, Dahms ra, et al: Six years of surgical wound surveillance • Diagnosis  of  a  deep  space  surgical  site  infection  by  at a tertiary care center. arch Surg 134:1041-1048, 1999. the surgeon • Symptoms  of  fever,  pain,  and  tenderness  leading  to  wound dehiscence or opening by a surgeon organ Space evidence to indicate that hospital­acquired MRSA is developing infection less than 30 days after surgery with no implant resistance to vancomycin (vancomycin intermediate­resistant S. infection less than 1 year after surgery with an implant and  aureus [VISA] and vancomycin­resistant S. aureus [VRSA]).5 infection;  involves  any  part  of  the  operation  opened  or  mani- Enterococcus spp. are commensals in the adult gastrointestinal pulated, plus one of the following: (GI) tract, have intrinsic resistance to a variety of antibiotics • Purulent  drainage  from  a  drain  placed  in  the  organ  (e.g., cephalosporins, clindamycin, aminoglycoside), and are the space first to exhibit resistance to vancomycin. • cultured organisms from material aspirated from the  In approximately one third of SSI cases, gram­negative organ space bacilli (Escherichia coli, Pseudomonas aeruginosa, and Enterobacter • abscess found on direct or radiologic examination or  spp.) are isolated. However, at locations at which high volumes during reoperation of GI operations are performed, the predominant bacterial • Diagnosis of organ space infection by a surgeon species are the gram­negative bacilli. Infrequent pathogens are adapted from Mangram aJ, horan tC, pearson ML, et al: Guideline for prevention group A beta­hemolytic streptococci and Clostridium perfringens. of surgical site infection. Infect Control hosp epidemiol 20:252, 1999. In recent years, the involvement of resistant organisms in the genesis of SSIs has increased, most notable in MRSA. A host of patient­ and operative procedure–related factors may contribute to the development of SSIs (Table 13­2).6 The normally occur in the nasal passages, mucous membranes, and risk of infection is related to the specific surgical procedure skin of carriers. The organism that has acquired resistance to performed and, hence, surgical wounds are classified according methicillin (methicillin­resistant S. aureus [MRSA]) consists to the relative risk of surgical site infections occurring—clean, of two subtypes, hospital­ and community­acquired MRSA. clean­contaminated, contaminated, and dirty (Table 13­3). In Hospital­acquired MRSA is associated with nosocomial infec­ the National Nosocomial Infections Surveillance System, the tions and affects immunocompromised individuals. It also risk of patients is stratified according to three important factors: occurs in patients with chronic wounds, those subjected to inva­ (1) wound classification (contaminated or dirty); (2) longer sive procedures, and those with prior antibiotic treatment. duration operation, defined as one that exceeds the 75th percen­ Community­acquired MRSA is associated with a variety of skin tile for a given procedure; and (3) medical characteristics of the and soft tissue infections in patients with and without risk patients as determined by the American Society of Anesthesiol­ factors for MRSA. Community­acquired MRSA (e.g., the ogy score of III, IV, or V (presence of severe systemic disease USA300 clone) has also been noted to affect SSIs. Hospital­ that results in functional limitations, is life­threatening, or is acquired MRSA isolates have a different antibiotic susceptibility expected to preclude survival from the operation) at the time of profile—they are usually resistant to at least three β­lactam operation.7 antibiotics and are usually susceptible to vancomycin, teico­ planin, and sulfamethoxazole. Community­acquired MRSA is presentation usually susceptible to clindamycin, with variable susceptibility SSIs most commonly occur 5 to 6 days postoperatively but may to erythromycin, vancomycin, and tetracycline. There is develop sooner or later than that. Approximately 80% to 90% K2Townsend_Chapter 13_main.indd 5 6/10/2011 12:36:19 PM
  6. 6. 13-6  section ii  PerioPerative ManageMent of all postoperative infections occur within 30 days after the patients are hospitalized for 6 days or less, 70% of postdischarge operative procedure. With the increased use of outpatient infections occur in that group. surgery and decreased length of stay in hospitals, 30% to 40% Superficial and deep SSIs are accompanied by erythema, of all wound infections have been shown to occur after hospital tenderness, edema, and occasionally drainage. The wound is discharge. Nevertheless, although less than 10% of surgical often soft or fluctuant at the site of infection, which is a depar­ ture from the firmness of the healing ridge present elsewhere in the wound. The patient may have leukocytosis and a low­grade fever. According to the Joint Commission (TJC), a surgical 4 table 13-2  risk Factors for postoperative Wound infection wound is considered infected if (1) there is drainage of grossly enVironMentaL  treatMent  purulent material drains from the wound, (2) the wound spon­ patient Factors Factors Factors taneously opens and drains purulent fluid, (3) the wound drains ascites contaminated  Drains fluid that is culture­positive or Gram stain–positive for bacteria, medications and (4) the surgeon notes erythema or drainage and opens the chronic  inadequate  emergency  wound after determining it to be infected. inflammation disinfection/sterilization procedure undernutrition inadequate skin  inadequate antibiotic  treatment obesity antisepsis coverage Prevention of surgical site infections relies on changing or Diabetes inadequate ventilation Preoperative  dealing with modifiable risk factors that predispose to surgical hospitalization site infections. However, many of these factors cannot be extremes of age Presence of a foreign  Prolonged operation changed, such as age, complexity of the surgical procedure, body and morbid obesity. Patients who are heavy smokers are Hypercholesterolemia encouraged to stop smoking at least 30 days before surgery, Hypoxemia glucose levels in diabetics must be treated appropriately, and Peripheral vascular disease severely malnourished patients should be given nutritional supplements for 7 to 14 days before surgery.8 Obese patients Postoperative anemia must be encouraged to lose weight if the procedure is elective Previous site of irradiation and there is time to achieve significant weight loss. Similarly, recent operation patients who are taking high doses of corticosteroids will have lower infection rates if they are weaned off corticosteroids or remote infection are at least taking a lower dose. Patients undergoing major Skin carriage of staphylococci intra­abdominal surgery are administered a bowel preparation Skin disease in the area of infection in the form of a lavage solution or strong cathartic, followed immunosuppression by oral nonabsorbable antibiotic(s), particularly for surgery of the colon and small bowel. Bowel preparation lowers the Data from National Nosocomial Infections Surveillance Systems (NNIS) System patient’s risk for infection from that of a contaminated case report: Data summary from January 1992–June 2001, issued august 2001. am J Infect Control 29:404-421, 2001. (25%) to a clean­contaminated case (5%). Hair is removed by clipping immediately before surgery and the skin is prepped at the time of operation with an antiseptic agent (e.g., alcohol, chlorhexidine, iodine). The role of preoperative decolonization in carriers of S. table 13-3  classification of surgical Wounds aureus undergoing general surgery is questionable, and the inFection   routine use of prophylactic vancomycin or teicoplanin (effective cateGorY criteria rate (%) against MRSA) is not recommended. Although perioperative clean no hollow viscus entered 1-3 antibiotics are widely used, prophylaxis is generally recom­ Primary wound closure mended for clean­contaminated or contaminated procedures in no inflammation which the risk of SSIs is high or in procedures in which vascular no breaks in aseptic technique elective procedure or orthopedics prostheses are used because the development of SSIs will have grave consequences (Table 13­4). For dirty or clean-  Hollow viscus entered but controlled 5-8 contaminated no inflammation contaminated wounds, the use of antibiotics is for therapeutic Primary wound closure purposes rather than for prophylaxis. For clean cases, prophy­ Minor break in aseptic technique laxis is controversial. For some surgical procedures, a first­ or Mechanical drain used Bowel preparation preoperatively second­generation cephalosporin is the accepted agent of choice. contaminated uncontrolled spillage from viscus 20-25 A small but significant benefit may be achieved with the pro­ inflammation apparent phylactic administration of a first­generation cephalosporin for open, traumatic wound certain types of clean surgery (e.g., mastectomy, herniorrhaphy). Major break in aseptic technique For clean­contaminated procedures, administration of preopera­ Dirty untreated, uncontrolled spillage from  30-40 tive antibiotics is indicated. The appropriate preoperative anti­ viscus Pus in operative wound biotic is a function of the most likely inoculum based on the open suppurative wound area being operated. For example, when a prosthesis may be Severe inflammation placed in a clean wound, preoperative antibiotics would includeK2 something to protect against S. aureus and streptococcal species. Townsend_Chapter 13_main.indd 6 6/10/2011 12:36:19 PM
  7. 7. Surgical coMPlicationS  chapter 13  13-7 SeCtion ii PerioPerative ManageMent table 13-4  prophylactic antimicrobial agent for selected surgical procedures proceDUre recoMMenDeD aGent potentiaL aLternatiVe cardiothoracic cefazolin or cefuroxime vancomycin, clindamycin vascular cefazolin or cefuroxime vancomycin, clindamycin gastroduodenal cefazolin cefoxitin, cefotetan, aminoglycoside, or fluoroquinolone +  antianaerobe open biliary cefazolin cefoxitin, cefotetan, or fluoroquinolone + antianaerobe laparoscopic cholecystectomy none — nonperforated appendicitis cefoxitin, cefotetan, cefazolin + metronidazole ertapenem, aminoglycoside, or fluoroquinolone + antianaerobe colorectal cefoxitin, cefotetan, ampicillin-sulbactam,  aminoglycoside, or fluoroquinolone + antianaerobe, aztreonam  ertapenem, cefazolin + metronidazole + clindamycin Hysterectomy cefazolin, cefuroxime, cefoxitin, cefotetan,  aminoglycoside, or fluoroquinolone + antianaerobe, aztreonam  ampicillin-sulbactam + clindamycin orthopedic implantation cefazolin, cefuroxime vancomycin, clindamycin Head and neck cefazolin, clindamycin — From Kirby Jp, Mazuski Je: prevention of surgical site infection. Surg Clin North am 89:365-389, 2009. A first­generation cephalosporin, such as cefazolin, would be contaminated instruments, avoidance of environ­ appropriate in this setting. For patients undergoing upper GI mental contamination, such as debris falling from tract surgery, complex biliary tract operations, or elective colonic overhead) resection, administration of a second­generation cephalosporin 7. Thorough drainage and irrigation of any pockets of such as cefoxitin or a penicillin derivative with a β­lactamase purulence in the wound with warm saline inhibitor is more suitable. Alternatively, ertapenem can y be used 8. Ensuring that the patient is kept in a euthermic state, for operations involving the lower GI tract. The surgeon will well­monitored, and fluid­resuscitated give a preoperative dose, intraoperative doses approximately 4 9. Expressing a decision about closing the skin or hours apart, and two postoperative doses appropriately spaced. packing the wound at the end of the procedure The timing of administration of prophylactic antibiotics is crit­ The use of drains remains somewhat controversial in pre­ ical. To be most effective, the antibiotic is administered IV venting postoperative wound infections. In general, there is within 30 minutes before the incision so that therapeutic tissue almost no indication for drains in this setting. However, placing levels have developed when the wound is created and exposed closed suction drains in very deep, large wounds and wounds to bacterial contamination. Usually, a period of anesthesia with large wound flaps to prevent the development of a seroma induction, preparation, and draping takes place that is adequate or hematoma is a worthwhile practice. to allow tissue levels to build up to therapeutic levels before the Treatment of SSIs depends on the depth of the infection. incision is made. Of equal importance is making certain that For both superficial and deep SSIs, skin staples are removed the prophylactic antibiotic is not administered for extended over the area of the infection and a cotton­tipped applicator periods postoperatively. To do so in the prophylactic setting is may be easily passed into the wound, with efflux of purulent to invite the development of drug­resistant organisms, as well as material and pus. The wound is gently explored with the serious complications, such as Clostridium difficile–associated cotton­tipped applicator or a finger to determine whether the colitis. fascia or muscle tissue is involved. If the fascia is intact, At the time of surgery, the operating surgeon plays a major débridement of any nonviable tissue is performed; the wound role in reducing or minimizing the presence of postoperative is irrigated with normal saline solution and packed to its base wound infections. The surgeon must be attentive to personal with saline­moistened gauze to allow healing of the wound hygiene (hand scrubbing) and that of the entire team. In addi­ from the base anteriorly, thus preventing premature skin tion, the surgeon must make certain that the patient undergoes closure. If widespread cellulitis or significant signs of infection a thorough skin preparation with appropriate antiseptic solu­ (e.g., fever, tachycardia), are noted, administration of IV anti­ tions and is draped in a sterile, careful fashion. During the biotics must be considered. Empirical therapy is started and operation, steps that have a positive impact on outcome are tailored according to culture and sensitivity data. The choice followed: of empirical antibiotics is based on the most likely culprit, 1. Careful handling of tissues including the possibility of MRSA. MRSA is treated with van­ 2. Meticulous dissection, hemostasis, and débridement comycin, linezolid, or clindamycin. Cultures are not routinely of devitalized tissue performed, except for patients who will be treated with antibi­ 3. Compulsive control of all intraluminal contents otics so that resistant organisms can be treated adequately. 4. Preservation of blood supply of the operated organs However, if the fascia has separated or purulent material 5. Elimination of any foreign body from the wound appears to be coming from deep to the fascia, there is obvious 6. Maintenance of strict asepsis by the operating team concern about dehiscence or an intra­abdominal abscess that (e.g., no holes in gloves, avoidance of the use of may require drainage or possibly a reoperation. K2Townsend_Chapter 13_main.indd 7 6/10/2011 12:36:19 PM
  8. 8. 13-8  section ii  PerioPerative ManageMent Wound cultures are controversial. If the wound is small, shock or with a severe illness often have associated vasoconstric­ superficial, and not associated with cellulitis or tissue necrosis, tion that results in poor perfusion of peripheral organs and cultures may not be necessary. However, if fascial dehiscence tissues, an effect accentuated by hypothermia. In a high­risk and a more complex infection are present, a culture is sent. A patient, a core temperature lower than 35° C is associated with deep SSI associated with grayish, dishwater­colored fluid, as a twofold to threefold increase in the incidence of early postop­ well as frank necrosis of the fascial layer, raises suspicion for the erative ischemia and a similar increase in the incidence of ven­ presence of a necrotizing type of infection. The presence of tricular tachyarrhythmia. Hypothermia also impairs platelet crepitus in any surgical wound or gram­positive rods (or both) function and reduces the activity of coagulation factors, thereby suggests the possibility of infection with C. perfringens. Rapid resulting in an increased risk for bleeding. Hypothermia results and expeditious surgical débridement is indicated in these in impaired macrophage function, reduced tissue oxygen tension, settings. and impaired collagen deposition, which predisposes wounds to Most postoperative infections are treated with healing by poor healing and infection. Other complications of hypothermia secondary intention, allowing the wound to heal from the include a relative diuresis, compromised hepatic function, and base anteriorly, with epithelialization being the final event. In some neurologic manifestations. Similarly, the patient’s ability some cases, when there is a question about the amount of to manage acid­base abnormalities is impaired. In severe cases, contamination, delayed primary closure may be considered. In the patient can have significant cardiac slowing and may be this setting, close observation of the wound for 5 days may be comatose, with low blood pressure, bradycardia, and a very low followed by closure of the skin or negative­pressure wound respiratory rate. therapy if the wound looks clean and the patient is otherwise doing well. treatment Prevention of hypothermia entails monitoring core tempera­ ture, especially in patients undergoing body cavity surgery or complicationS oF tHermal regulation surgery lasting longer than 1 hour, children and older adults, and patients in whom general epidural anesthesia is being con­ Hypothermia ducted.9 Sites of monitoring include pulmonary artery blood, tympanic membrane, esophagus and pharynx, rectum, and Causes urinary bladder. While the patient is being anesthetized, and Optimal function of physiologic systems in the body occurs during skin preparation, significant evaporative cooling can within a narrow range of core temperatures. A 2° C drop in body take place; the patient is kept warm by increasing the ambient temperature or a 3° C increase signifies a health emergency that temperature and using heated humidifiers and warmed IV is life­threatening and requires immediate intervention. Hypo­ fluid. After the patient is draped, the room temperature can be thermia can result from a number of mechanisms preoperatively, lowered to a more comfortable setting. A forced­air warming intraoperatively, or postoperatively. A trauma patient with inju­ device that provides active cutaneous warming is placed on the ries in a cold environment can suffer significant hypothermia, patient. Passive surface warming is not effective in conserving and paralysis can lead to hypothermia because of loss of the heat. There is some evidence that a considerable amount of shiver mechanism. heat is lost through the head of the patient, so simply covering Hypothermia develops in patients undergoing rapid resus­ the patient’s head during surgery may prevent significant heat citation with cool IV fluids, transfusions, or intracavitary irriga­ loss. tion with cold irrigant, and in patients undergoing a prolonged In the perioperative period, mild hypothermia is common­ surgical procedure with low ambient room temperature and a place and patients usually shiver because the anesthesia impairs large, exposed operative area subjected to significant evaporative thermoregulation. Many patients who shiver after anesthesia, cooling. Almost all anesthetics impair thermoregulation and however, are hypothermic. Treatment of the hypothermia with render the patient susceptible to hypothermia in the typically forced­air warming systems and radiant heaters will also reduce cool operating room environment.9 Advanced age and opioid the shivering.9 In a severely hypothermic patient who does not analgesia also reduce perioperative shivering. Propofol causes require immediate operative intervention; attention must be vasodilation and significant redistribution hypothermia. Postop­ directed toward rewarming by the following methods: eratively, hypothermia can result from cool ambient room tem­ 1. Immediate placement of warm blankets, as well as perature, rapid administration of IV fluids or blood, and failure currently available forced­air warming devices to keep patients covered when they are only partially responsive. 2. Infusion of blood and IV fluids through a warming More than 80% of elective operative procedures are associated device with a drop in body temperature, and 50% of trauma patients 3. Heating and humidifying inhalational gases are hypothermic on arrival in the operating suite. 4. Peritoneal lavage with warmed fluids 5. Rewarming infusion devices with an arteriovenous presentation system Hypothermia is uncomfortable because of the intense cold sen­ 6. In rare cases, cardiopulmonary bypass sation and shivering. It may also be associated with profound Special attention must be paid to cardiac monitoring effects on the cardiovascular system, coagulation, wound healing, during the rewarming process because cardiac irritability may be and infection. A core temperature lower than 35° C after surgery a significant problem. Similarly, acid­base disturbances must be triggers a significant peripheral sympathetic nervous system aggressively corrected while the patient is being rewarmed. Once response, consisting of an increased norepinephrine level, vaso­ in the operating room, measures noted earlier to keep the patientK2 constriction, and elevated arterial blood pressure. Patients in warm are applied. Townsend_Chapter 13_main.indd 8 6/10/2011 12:36:19 PM
  9. 9. Surgical coMPlicationS  chapter 13  13-9 malignant Hyperthermia Box 13-3  Management of Malignant hyperthermia SeCtion ii PerioPerative ManageMent Causes Discontinue the triggering anesthetic. Malignant hyperthermia (MH) is a life­threatening hypermeta­ Hyperventilate the patient with 100% oxygen. bolic crisis manifested during or after exposure to a triggering administer alternative anesthesia. general anesthetic in susceptible individuals. It is estimated that terminate surgery. 5 MH occurs in 1 in 30,000 to 50,000 adults. Mortality from give dantrolene, 2.5 mg/kg, as a bolus and repeat every 5 min,  38 MH has decreased to less than 10% in the last 15 years as a then 1 to 2 mg/kg/hr until normalization or disappearance  result of improved monitoring standards that allow early detec­ of symptoms. tion of MH, availability of dantrolene, and increased use of check  and  monitor  arterial  blood  gas  and  creatine  kinase,   susceptibility testing. electrolyte, lactate, and myoglobin levels. Susceptibility to MH is inherited as an autosomal domi­ Monitor the electrocardiogram, vital signs, and urine output. nant disease with variable penetrance. To date, two MH suscep­ adjunctive and supportive measures are carried out: tibility genes have been identified in humans and four mapped • volatile  vaporizers  are  removed  from  the  anesthesia  to specific chromosomes but not definitely identified. The muta­ machine. tion results in altered calcium regulation in skeletal muscle in • carbon dioxide canisters, bellows, and gas hoses are  the form of enhanced efflux of calcium from the sarcoplasmic changed. reticulum into the myoplasm. Halogenated inhalational anes­ • Surface  cooling  is  achieved  with  ice  packs  and  core  thetic agents (e.g., halothane, enflurane, isoflurane, desflurane, cooling with cool parenteral fluids. and sevoflurane) and depolarizing muscle relaxants (e.g., succi­ • acidosis  is  monitored  and  treated  with  sodium  nylcholine, suxamethonium) cause a rise in the myoplasmic Ca2+ bicarbonate. concentration. When an MH­susceptible individual is exposed • arrhythmias  are  controlled  with  beta  blockers  or  to a triggering anesthetic, there is abnormal release of Ca2+, lidocaine. which leads to prolonged activation of muscle filaments, culmi­ • urine  output  more  than2 ml/kg/hr  is  promoted;  nating in rigidity and hypermetabolism. Uncontrolled glycolysis furosemide (lasix) or mannitol and a glucose-insulin  and aerobic metabolism give rise to cellular hypoxia, progressive infusion  (0.2 u/kg  in  a  50%  glucose  solution)  are  lactic acidosis, and hypercapnia. The continuous muscle activa­ given  for  hyperkalemia,  hypercalcemia,  and  tion with adenosine triphosphate breakdown results in excessive myoglobulinuria. generation of heat. If untreated, myocyte death and rhabdomy­ the patient is transferred to the intensive care unit to monitor  olysis result in hyperkalemia and myoglobulinuria. Eventually, for recurrence. disseminated coagulopathy, congestive heart failure (CHF), bowel ischemia, and compartment syndrome develop. Once MH is suspected or diagnosed, the steps outlined in presentation and management Box 13­3 are followed. Dantrolene is a muscle relaxant. In the MH can be prevented by identifying at­risk individuals before solution form, it is highly irritating to the vein and must be surgery. MH susceptibility is suspected preoperatively in a administered in a large vein. When given intravenously, it blocks patient with a family history of MH or a personal history of up to 75% of skeletal muscle contraction and never causes myalgia after exercise, a tendency for the development of fever, paralysis. The plasma elimination half­life is 12 hours. Dan­ muscular disease, and intolerance to caffeine. In these cases, the trolene is metabolized in the liver to 5­hydroxydantrolene, creatine kinase level is checked, and a caffeine and halothane which also acts as a muscle relaxant. Side effects reported with contraction test (or an in vitro contracture test developed in dantrolene therapy include muscle weakness, phlebitis, respira­ Europe) may be performed on a muscle biopsy specimen from tory failure, GI discomfort, hepatotoxicity, dizziness, confusion, the thigh.10 MH­susceptible individuals confirmed by abnormal and drowsiness. Another agent, azumolene, is 30 times more skeletal muscle biopsy findings or those with suspected MH water­soluble than and equipotent to dantrolene in the treat­ susceptibility who decline a contracture test are given a trigger­ ment of MH; like dantrolene, it does not affect the heart. Its free anesthetic (e.g., barbiturate, benzodiazepine, opioid, pro­ main side effect is marked pulmonary hypertension. However, pofol, etomidate, ketamine, nitrous oxide, nondepolarizing azumolene is not in clinical use at this time. neuromuscular blocker). Unsuspected MH­susceptible individuals may manifest postoperative Fever MH for the first time during or immediately after the adminis­ tration of a triggering general anesthetic. The clinical manifesta­ Causes tions of MH are not uniform and vary in onset and severity. One of the most concerning clinical findings in a patient post­ Some patients manifest the abortive form of MH (e.g., tachy­ operatively is the development of fever. Fever describes a rise in cardia, arrhythmia, raised temperature, acidosis). Others, after core temperature, modulation of which is managed by the ante­ intubation with succinylcholine, demonstrate loss of twitches on rior hypothalamus. Fever may result from bacterial invasion or neuromuscular stimulation and develop muscle rigidity. An their toxins, which stimulate the production of cytokines. inability to open the mouth as a result of masseter muscle spasm Trauma (including surgery) and critical illness also invoke a is a pathognomonic early sign and indicates susceptibility to cytokine response. Cytokines are low­molecular­weight proteins MH. Other manifestations include tachypnea, hypercapnia, that act in an autocrine, paracrine, and/or endocrine fashion to skin flushing, hypoxemia, hypotension, electrolyte abnormali­ influence a broad range of cellular function and exhibit proin­ ties, rhabdomyolysis, and hyperthermia. flammatory and anti­inflammatory effects. The inflammatory K2Townsend_Chapter 13_main.indd 9 6/10/2011 12:36:19 PM
  10. 10. 13-10  section ii  PerioPerative ManageMent infections are preventable and are considered a “never” compli­ table 13-5  causes of postoperative Fever cation by the Centers of Medicare and Medicaid Services.13 inFectioUs noninFectioUs CR­BSI results from microorganisms that colonize the hubs or abscess acute hepatic necrosis from contamination of the injection site of the central venous acalculous cholecystitis adrenal insufficiency catheter (intraluminal source) or skin surrounding the insertion site (extraluminal source). Coagulase­negative staphylococci, Bacteremia allergic reaction hospital­acquired bacteria (e.g., MRSA, multidrug­resistant Decubitus ulcers atelectasis gram­negative bacilli, fungal species [Candida albicans]) are the Device-related infections Dehydration most common organisms responsible for CR­BSI. S. aureus bac­ empyema Drug reaction teremia is associated with higher mortality and venous throm­ bosis. Metastatic infections (endocarditis) are uncommon but endocarditis Head injury represent a serious complication of CR­BSI. The duration of 6 Fungal sepsis Hepatoma central venous catheter placement, patient location (outpatient Hepatitis Hyperthyroidism versus inpatient), type of catheter, number of lumens and Meningitis lymphoma manipulations daily, emergent placement, need for total paren­ teral nutrition (TPN), presence of unnecessary connectors, and osteomyelitis Myocardial infarction whether best care practices are followed are risk factors for BSI.14 Pseudomembranous colitis Pancreatitis Parotitis Pheochromocytoma presentation and management In evaluating a patient with fever, one has to take into consid­ Perineal infections Pulmonary embolus eration the type of surgery performed, patient’s immune status, Peritonitis retroperitoneal hematoma underlying primary disease process, duration of hospital stay, Pharyngitis Solid organ hematoma and epidemiology of hospital infections. Pneumonia Subarachnoid hemorrhage High fever that fluctuates or is sustained and that occurs 5 to 8 days after surgery is more worrisome than fever that occurs retained foreign body Systemic inflammatory early postoperatively. In the first 48 to 72 hours after abdominal Sinusitis response syndrome surgery, atelectasis is often believed to be the cause of the fever. Soft tissue infection thrombophlebitis Occasionally, clostridial or streptococcal SSIs can manifest as tracheobronchitis transfusion reaction fever within the first 72 hours of surgery. Temperatures that are elevated 5 to 8 days postoperatively demand immediate atten­ urinary tract infection Withdrawal syndromes tion and, at times, intervention. Evaluation involves studying Wound infection the six Ws: wind (lungs), wound, water (urinary tract), waste (lower GI tract), wonder drug (e.g., antibiotics), and walker (e.g., thrombosis). The patient’s symptoms usually indicate the response results in the production of a variety of mediators that organ system involved with infection; cough and productive induce a febrile inflammatory response, also known as systemic sputum suggest pneumonia, dysuria and frequency indicate a inflammatory response syndrome.11 Hence, fever in the post­ UTI, watery foul­smelling diarrhea develops as a result of infec­ operative period may be the result of an infection or caused tion with C. difficile, pain in the calf may be caused by deep by systemic inflammatory response syndrome. Fever after venous thrombosis (DVT), and flank pain may be caused by surgery is reported to occur in up to two thirds of patients, and pyelonephritis. Physical examination may show an SSI, phlebi­ infection is the cause of fever in approximately one third of cases. tis, tenderness on palpation of the abdomen, flank, or calf, or Numerous disease states can cause fever in the postoperative cellulitis at the site of a central venous catheter. period (Table 13­5). A complete blood count, urinalysis and culture, radiograph The most common infections, however, are health care– of the chest, and blood culture are essential initial tests. A associated infections—SSI, urinary tract infection (UTI), intra­ chest radiograph may show a progressive infiltrate suggestive of vascular catheter–related bloodstream infection (CR­BSI), and the presence of pneumonia. Urinalysis showing more than 105 pneumonia. Urinary tract infection is a common postoperative colony­forming units/milliliter (CFU/mL) in a noncatheterized event and a significant source of morbidity in postsurgical patient and more than 103 CFU/mL in a catheterized patient patients. A major predisposing factor is the presence of a urinary indicates a urinary tract infection. The diagnosis of CR­BSI rests catheter; the risk increases with increased duration of catheter­ on culture data because physical examination is usually unreveal­ ization (>2 days). Endogenous bacteria (colonic flora, most ing. There is no gold standard for how to use blood cultures. common E. coli) are the most common source of catheter­related Two simultaneous blood cultures or paired blood cultures (i.e., urinary tract infection in patients with short­term catheteriza­ simultaneous peripheral and central blood cultures) are com­ tion. With prolonged catheterization, additional bacteria are monly used. Peripheral blood cultures showing bacteremia and found. In the critically ill surgical patient, candiduria accounts isolation of 15 CFUs or 102 CFUs from an IV catheter indicate for approximately 10% of nosocomial urinary tract infection. the presence of a CR­BSI. In tunneled catheters, a quantitative The presence of an indwelling catheter, diabetes mellitus, use of colony count that is 5­ to 10­fold higher in cultures drawn antibiotics, advanced age, and underlying anatomic urologic through the central venous catheter is predictive of CRC­BSI. abnormalities are risk factors for candiduria.12 If paired cultures are obtained, positive culture more than2 The use of central venous catheters carries a risk of CR­BSI hours before peripheral culture indicates the presence of CR­BSI.K2 that increases hospital stay and morbidity and mortality. The After removal of the catheter, the tip may be sent for quantitative Townsend_Chapter 13_main.indd 10 6/10/2011 12:36:19 PM