According to the Centers for Disease Control and Prevention and the National Hospital Discharge Summary, nearly 1.3 million cesarean deliveries were performed in 2013 (Martin, 2015). This stands as the most common abdominal surgery in the United States and by far the most frequently performed surgery in obstetrics. Cesarean delivery is discussed in detail in Chapter 25 (p. 403), and postoperative complications following this procedure contribute substantively to pregnancy-related morbidity and mortality rates. In their sobering analysis of data from the Pregnancy Mortality Surveillance System, for example, Creanga and colleagues (2015) found that infection, venous thromboembolism, and hemorrhage contributed 13.6 percent, 9.6 percent, and 11.4 percent, respectively, to all pregnancy-related deaths from 2006 to 2010. The contribution from infection actually represented a significant increase compared with previously reported epochs. The importance of recognizing and appropriately managing such postoperative complications is highlighted by the fact that subsets of the resultant deaths are unquestionably preventable.
Puerperal fever is defined by a temperature increase to 38.0°C (100.4°F) or greater in the postpartum period, whereas puerperal infection refers to any bacterial infection of the genital tract. The causes of puerperal fever are numerous, and the presence of fever by itself is not diagnostic of infection. Indeed, transient, low-grade fever in the early postpartum period is usually benign and does not require treatment. However, most persistent or high-grade fevers—39.0°C or higher—are associated with infection, most commonly uterine infection.
Several risk factors for puerperal infection have been identified, but cesarean delivery is the single most important risk for infection, conferring a 20- to 30-fold relative risk compared with vaginal delivery (Maharaj, 2007). In an older study, Filker and Monif (1979) reported that only 21 percent of women febrile in the first 24 hours who were delivered vaginally were found to have infection. This contrasts with 72 percent of those with fever who had undergone cesarean delivery.
Extragenital causes of puerperal fever include breast engorgement, mastitis, urinary tract infection, septic pelvic thrombophlebitis, respiratory complications, and, in women who undergo laparotomy, wound infection. The broad differential diagnosis of postpartum fever underscores the importance of a prompt and thorough evaluation in any woman who is noted to have a temperature above these threshold values.
Breast engorgement commonly causes a brief temperature elevation. Approximately 15 percent of all women in the first few postpartum days develop fever from breast engorgement, but it rarely exceeds 39°C. Engorgement is more common in women who do not breastfeed and is typically associated with breast pain and marked bilateral firmness during examination. This fever characteristically lasts no longer than 24 hours. Treatment is supportive with breast binders, cool packs, and oral analgesics as needed. That said, evidence-based recommendations for the management of breast engorgement are lacking (Mangesi, 2010).
In contrast to engorgement, fever from bacterial mastitis develops later in the puerperium and usually is sustained. Intense breast pain is typically unilateral, and obvious cellulitis, with erythema and warmth, is evident on the affected breast (Fig. 32-1). Systemic symptoms including chills are common, and tachycardia often accompanies the fever. Mastitis is usually caused by staphylococcal species, and, increasingly, methicillin-resistant Staphylococcus aureus (MRSA) is being reported as the principal pathogen in women with these infections (Lee, 2010; Stafford, 2008).
FIGURE 32-1
Postpartum breast abscess. A. Firm margins were palpated around the erythematous area in this left breast. This finding was concerning for an abscess and prompted breast sonography. B. In this sonogram of the same breast, a predominantly cystic area with complex-appearing fluid is marked by calipers. Following initiation of intravenous antibiotics, the abscess was subsequently drained and packed in the operating room.
Treatment is empiric and usually includes an antistaphylococcal penicillin. Dicloxacillin, 500 mg orally four times daily, may be selected. Erythromycin is given to women who are penicillin sensitive. Even though clinical response may be prompt, treatment should be continued for 10 to 14 days. For resistant staphylococci, vancomycin or another anti-MRSA antimicrobial is given.
Marshall and coworkers (1975) demonstrated the importance of continued breastfeeding. They reported that the three abscesses that developed in 65 women with mastitis were in 15 women who quit breastfeeding. Vigorous milk expression may be sufficient treatment alone (Thomsen, 1984). Sometimes the newborn will not nurse on the inflamed breast, and a breast pump can be used.
An abscess should be suspected when defervescence does not follow within 48 to 72 hours of mastitis treatment or when a mass is palpable. If suppuration is suspected clinically, breast sonography can help confirm the diagnosis of breast abscess. As seen in Figure 32-1B, sonographic identification of a cystic cavity with associated adjacent inflammatory change confirms the diagnosis.
In these cases, drainage of the abscess cavity is indicated in addition to intravenous antibiotics. Incision and drainage followed by cavity packing is one approach. For substantial abscesses, this often requires general anesthesia. Alternatively, aspiration has been demonstrated to result in more rapid healing compared with surgical incision and drainage and has the added benefit of avoiding exposure to general anesthesia (Naeem, 2012).
Many physiologic and hormonal changes during pregnancy leave the urinary tract vulnerable to infection. These include hydroureter, decreased ureteral muscle tone and peristalsis from increased progesterone levels, and expanded filling capacity and incomplete emptying of the bladder. These persist for several weeks into the puerperium. In one review of 23 cases of postpartum pyelonephritis, 20 cases (87 percent) were diagnosed in the first 3 weeks after delivery (McDonnold, 2012).
Causes for postpartum pyelonephritis include catheterization during labor, operative delivery, and labor trauma. Moreover, sensation of bladder distention is often diminished by conduction analgesia or by discomfort from genital tract lacerations. Normal postpartum diuresis may worsen bladder overdistention, and catheterization to relieve retention can lead to urinary tract infection.
Clinically, pyelonephritis can be difficult to diagnose postpartum. In typical cases, bacteriuria, pyuria, costovertebral angle tenderness, and spiking temperature clearly indicate renal infection. However, the clinical picture can vary. For example, the first sign of renal infection in puerperal women may be a temperature elevation, but costovertebral angle tenderness may not develop until later. The clinical diagnosis is confirmed by demonstrating bacteriuria microscopically and by urine culture. Because lochia can often contaminate clean-catch specimens, a catheterized specimen may be more informative. Blood cultures are not indicated when the diagnosis is straightforward. Even when bacteremia is found, the organisms identified are almost invariably identical to those found in the urine culture. When the diagnosis is unclear, however, blood cultures can be considered.
Empiric therapy is begun without waiting for culture results. Of suitable regimens, ampicillin plus gentamicin; cefazolin or ceftriaxone; or an extended-spectrum antibiotic were all 95-percent effective in randomized trials (Sanchez-Ramos, 1995; Wing, 1998, 2000). Serum creatinine may require monitoring if nephrotoxic drugs are given for a prolonged period of time or to women with any degree of renal insufficiency. Intravenous hydration is essential to ensure adequate urine flow, and urine output should be monitored carefully in the early course of treatment. Fever is treated with typical oral antipyretics, but marked hyperthermia may require physical cooling such as ice packs or a cooling blanket. With any of the regimens discussed, response is usually prompt, and most women are afebrile by 72 hours (Hill, 2005; Sheffield, 2005; Wing, 2000). After discharge, most continue oral therapy to complete a total of 7 to 14 days.
These most often are seen within the first 24 hours following delivery. They typically develop in women delivered by cesarean or those in whom general anesthesia is required. Pulmonary embolism is discussed separately on page 519.
This is the most common postoperative respiratory complication. It is seen in patients with a diminished cough reflex who have focal airway obstruction from thick secretions. Although it is not conclusively proven that atelectasis causes fever, pyrexia is thought to stem from infection with normal flora that proliferate distal to the obstruction (Engoren, 1995).
Chest radiography is frequently obtained in women with suspected atelectasis, however, findings often do not correlate with postoperative fever (Engoren, 1995; Roberts, 1988). Radiography classically shows linear densities in the lower lung fields.
Atelectasis is best prevented with the use of routine coughing and deep breathing on a fixed schedule, usually every 4 hours for at least the first postoperative day. Incentive spirometry is also frequently recommended to prevent atelectasis, despite that randomized trials have failed to confirm the effectiveness of this strategy (do Nascimento Junior, 2014; Tyson, 2015). Atelectasis is usually temporary (up to 2 days), is self-limited, and rarely slows patient recovery or hospital discharge. Its importance mainly lies in its clinical similarity to other pulmonary conditions. Thus, atelectasis often ultimately is a diagnosis of exclusion.
The possibility of aspiration of acidic gastric contents must be suspected in the woman with severe or persistent pulmonary findings. Especially with the use of general anesthesia, aspiration can cause severe chemical pneumonitis and has historically been among the most common causes of anesthesia-related deaths in obstetrics. The physiologic changes of pregnancy such as relaxation of the lower esophageal sphincter and delayed gastric emptying place pregnant women at increased risk for aspiration. Labor prolongs gastric emptying times even further.
When highly acidic liquid is inspired, decreased oxygen saturation is likely to develop, along with tachypnea, bronchospasm, rhonchi, rales, atelectasis, cyanosis, tachycardia, and hypotension. At the injury sites, there is pulmonary capillary leakage and exudation of protein-rich fluid containing numerous erythrocytes into the lung interstitium and alveoli. This causes decreased pulmonary compliance, shunting of blood, and severe hypoxemia. Radiographic changes may not appear immediately, and these may be variable, although the right lung most often is affected. Therefore, chest radiographs alone should not be used to exclude aspiration.
Primary treatment is supportive and principally involves providing adequate oxygenation and ventilation. There is no convincing clinical or experimental evidence that corticosteroid therapy or prophylactic antimicrobial administration is beneficial (Marik, 2001, 2011). If clinical evidence of infection develops, however, then vigorous treatment is given. Surveillance for progression to acute respiratory distress syndrome (ARDS) is essential, as described in Chapter 7 (p. 95).
Because of its severity, prevention of aspiration pneumonitis is of paramount importance in obstetrics. Unfortunately, however, according to the American Society of Anesthesiologists Task Force on Obstetric Anesthesia (2007), a specific “safe” fasting time prior to labor or delivery has not been determined. Recommendations from the American Society of Anesthesiologists, which are endorsed by the American College of Obstetricians and Gynecologists (2015), allow a modest intake of clear liquids for women with uncomplicated clinical courses in labor. However, a fasting period of 6 to 8 hours for solids before elective cesarean delivery is recommended. Sodium citrate with citric acid effectively neutralizes gastric contents and should be administered to women before anesthesia induction (Gibbs, 1984). The liberal use of acid-neutralizing agents and avoidance of general anesthesia are probably the two most important aspects of aspiration prevention in gravidas. The management of anesthesia is discussed further in Chapter 19 (p. 311).
As discussed, cesarean delivery places a woman at extraordinary risk for developing uterine infection. Prolonged labor and membrane rupture, multiple cervical examinations, and internal fetal monitoring are recognized risks for metritis, but abdominal delivery is the single biggest factor for developing postpartum infection. The incidence of metritis following surgical delivery varies with socioeconomic factors, but serious infections are now much less common with routine use of perioperative antibiotics, discussed in Chapter 18 (p. 295).
Organisms that contaminate and invade surgical incisions and lacerations tend to be of relatively low virulence and seldom initiate infection in healthy tissues. Although more virulent bacteria may be introduced from exogenous sources, in modern obstetrics, an epidemic of major puerperal sepsis rarely develops.
As an exception, serious infections with group A β-hemolytic streptococcus—Streptococcus pyogenes—have been documented since the 1980s. This highly virulent organism may cause severe and often necrotizing postpartum genital tract infections and a toxic-shock-like syndrome (Anderson, 2014; Aronoff, 2008; Castagnola, 2008). Moreover, a delay in diagnosis may lead to an increased risk of morbidity and maternal mortality (Boie, 2015). Udagawa and associates (1999) reviewed 30 cases of peripartum or postpartum Group A infections. Of 17 in whom infection manifested before, during, or within 12 hours of delivery, the maternal mortality rate was 88 percent from obvious infection, and the fetal mortality rate was 60 percent. In 13 women who deteriorated more than 12 hours postpartum, the maternal death rate was 55 percent, and there were no neonatal deaths.
Organisms usually responsible for female genital tract infections are listed in Table 32-1. Puerperal pelvic infections are typically polymicrobial and are almost always caused by bacteria that comprise the normal flora of the bowel, vagina, and cervix (Gilstrap, 1979). As mentioned, the individual species of bacteria typically isolated are considered to be of low virulence, but the polymicrobial nature of the infections enhances bacterial synergy. Hematomas and devitalized tissue increase pathogenicity even further. Under these circumstances, virulence is enhanced sufficiently to cause uterine infection that may progress to extensive pelvic cellulitis, abscess, peritonitis, and suppurative thrombophlebitis.
| Aerobes |
| Group A, B, and D streptococci |
| Enterococcus |
| Gram-negative rods: E coli, Klebsiella, and Proteus spp |
| Staphylococcus aureus |
| Gardnerella vaginalis |
| Anaerobes |
| Peptostreptococcus spp |
| Prevotella spp |
| Bacteroides fragilis group |
| Clostridium spp |
| Fusobacterium spp |
| Other |
| Mycoplasma hominis |
| Chlamydia trachomatis |
| Neisseria gonorrhoeae |
The uterine cavity usually is sterile before rupture of the amnionic sac. As the consequence of labor and associated manipulations, amnionic fluid and presumably the uterus commonly become contaminated with anaerobic and aerobic bacteria. For example, Gilstrap and Cunningham (1979) cultured amnionic fluid obtained at cesarean delivery performed in women in labor with membranes ruptured more than 6 hours. They identified an average of 2.5 organisms from each woman. The following bacteria were isolated in the noted percentages: anaerobic and aerobic organisms, 63 percent; anaerobes alone, 30 percent; and aerobes alone, 7 percent. Predominant anaerobic organisms were gram-positive cocci, namely, Peptostreptococcus and Peptococcus, 45 percent; Bacteroides, 9 percent; and Clostridium, 3 percent. Gram-positive aerobic cocci also were common and included Enterococcus, 14 percent, and group B Streptococcus, 8 percent. Of gram-negative organisms, Escherichia coli composed 9 percent of isolates. Gibbs (1987) reemphasized the importance of these organisms and reported an increasing prevalence of Bacteroides bivius as a cause of female pelvic infection. Walmer and colleagues (1988) also provided evidence for Enterococcus in the pathogenesis of these infections.
The pathogenesis of uterine infection following cesarean delivery is that of an infected surgical incision. As noted, bacteria gain access to amnionic fluid during labor, and postpartum they invade devitalized uterine tissue. Invariably, with uterine infections that follow cesarean delivery, there is myometritis with parametrial cellulitis. Hence, the term metritis is more accurate than endometritis. With early treatment, the infection typically remains limited to the uterus and parametrial tissue. As discussed subsequently, however, the bacteria can spread deeply into the pelvis and cause additional and sometimes severe infectious morbidity.
The clinical picture of metritis varies, but fever is the hallmark sign of postpartum uterine infection. The degree of temperature elevation is intuitively proportional to the extent of infection. When confined to the endometrium (decidua) and superficial myometrium, cases are mild, and fever tends to be low-grade. With more severe infection, temperatures often exceed 38.3°C. Chills may accompany fever and suggest bacteremia, which may be documented in up to one fourth of women with uterine infection following cesarean delivery (DiZerega, 1979). The pulse rate typically follows the temperature curve.
In affected women, abdominal pain is common, and postpartum uterine contractions (afterpains) may be bothersome. One or both sides of the abdomen are typically tender, and parametrial tenderness is elicited during bimanual examination. Even in the early stages, an offensive odor may develop, long regarded as an important sign of uterine infection. However, foul-smelling lochia is found in many women without evidence of infection, and this sign should not be considered pathognomonic. Conversely, some infections, notably those due to group A β-hemolytic streptococci, frequently are associated with scant, odorless lochia. Leukocytosis may range from 15,000 to 30,000 cells per μL. However, in view of the physiologic leukocytosis of the early puerperium, these findings are difficult to interpret. Bacterial cultures of the genital tract are not typically useful in guiding therapy, and routinely obtaining them is not recommended.
Postcesarean delivery metritis is treated empirically with parenterally administered broad-spectrum antibiotics. Initial treatment is directed against most of the mixed flora bacteria listed in Table 32-1. With appropriate antimicrobial coverage, clinical improvement will be seen in 48 to 72 hours in nearly 90 percent of women treated. Those who have been afebrile for at least 24 hours may typically be discharged. Further oral antibiotic therapy is not needed (Mackeen, 2015). Persistence of fever after 72 hours, however, mandates a careful search for causes of refractory infection, including an assessment for nonpelvic sources. Complications of metritis that cause persistent fever despite appropriate therapy include parametrial phlegmons, surgical incisional and pelvic abscesses, and septic pelvic thrombophlebitis.
Several antimicrobial regimens have proven efficacy for the treatment of pelvic infections following cesarean delivery (Table 32-2). Although anaerobic coverage is not typically necessary with postpartum metritis, it is an essential component of the treatment of postcesarean infections given the presence of devitalized tissue.
| Regimen | Comments |
|---|---|
| Clindamycin + gentamicin | “Gold standard,” 90–97% efficacy, once-daily gentamicin dosing acceptable PLUS Ampicillin added with sepsis syndrome or suspected enterococcal infection |
| Clindamycin + aztreonam | Gentamicin substitute for renal insufficiency |
| Extended-spectrum penicillin | Piperacillin, piperacillin tazobactam, ampicillin/sulbactam, or ticarcillin/clavulanate |
| Cephalosporin | Cefotetan, cefoxitin, or cefotaxime |
| Vancomycin | Added to other regimens for suspected Staphylococcus aureus infections |
| Metronidazole + ampicillin + gentamicin | Metronidazole has excellent anaerobic coverage |
| Carbapenem | Imipenem/cilastatin, meropenem, ertapenem reserved for special indications |
In 1979, diZerega and coworkers compared the effectiveness of clindamycin plus gentamicin against a regimen of penicillin G plus gentamicin for treatment of pelvic infections following cesarean delivery. Women given the clindamycin and gentamicin regimen had a favorable response 95 percent of the time. Accordingly, most obstetricians now consider this regimen to be the standard against which others are measured (Mackeen, 2015). Walmer and associates (1988) provided evidence that enterococcal infections may be associated with its clinical failure. Thus, many add ampicillin to the clindamycin and gentamicin regimen, either initially or following a failed response by 48 to 72 hours. The University of Alabama group subsequently reaffirmed the efficacy of this regimen given to 322 women with postcesarean metritis and pelvic cellulitis (Brumfield, 2000). Of these, 54 percent were cured with the original two-drug regimen. Another 40 percent in whom ampicillin was added at 48 hours responded. Of the 19 women (6 percent) who did not respond to “triple therapy,” seven had a wound infection that required drainage.
Regarding gentamicin, measuring peak and trough serum gentamicin concentrations is not needed in most women, and once-daily dosing is now used by many. Because the potential for nephrotoxicity and ototoxicity is worrisome with gentamicin in the event of diminished glomerular filtration, such women can be given a combination of clindamycin and second-generation cephalosporin. Also recommended is a combination of clindamycin and aztreonam, a monobactam compound with activity against gram-negative aerobic pathogens similar to the aminoglycosides.
β-Lactam antibiotics have spectra that include activity against many anaerobic pathogens and have been used successfully for decades to treat these infections. Many of the popular and effective multiagent regimens include a drug from this group. Some of these have been proven effective when used alone. Examples include some cephalosporins—cefoxitin, cefotetan, and cefotaxime, among others. Extended-spectrum penicillins such as piperacillin, ticarcillin, and mezlocillin are other examples. β-Lactam antibiotics are inherently safe, and except for allergic reactions, they are free of major toxicity. Another advantage is the cost-effectiveness of administering only one drug. The β-lactamase inhibitors clavulanic acid, sulbactam, and tazobactam have been combined with ampicillin, amoxicillin, and ticarcillin to extend their spectra, and these augmented antibiotics are also effective.
Metronidazole has excellent anaerobic coverage and can be used as a substitute for clindamycin. Given with ampicillin and an aminoglycoside, it provides excellent coverage for most bacteria that cause serious pelvic infections.
Imipenem is a carbapenem that has broad-spectrum coverage against most organisms associated with metritis. It is used in combination with cilastatin, which inhibits the renal metabolism of imipenem. Although this will be effective in most cases of metritis, it seems reasonable to reserve it for more serious, typically nonobstetric infections.
As discussed in Chapter 18 (p. 295), perioperative administration of antibiotics at time of cesarean delivery appreciably reduces infectious morbidity rates. A number of investigators have confirmed reductions in rates of metritis and wound infections when prophylactic antibiotics are utilized (Dinsmoor, 2009; Smaill, 2010). Both laboring women and those undergoing elective cesarean delivery receive benefit from prophylaxis. Administration of antibiotics prior to skin incision results in greater reductions of postoperative metritis rates compared with administration after cord clamping (Sullivan, 2007; Thigpen, 2005). Consequently, the American College of Obstetricians and Gynecologists (2016) recommends that antimicrobial prophylaxis be given to all women undergoing cesarean delivery unless the patient is already receiving appropriate antibiotics, for example, those being treated for chorioamnionitis, and that prophylaxis should be administered up to 60 minutes prior to skin incision when possible. Single-agent, first-generation cephalosporins are considered first-line antibiotics unless a significant allergy is present (American College of Obstetricians and Gynecologists, 2016). They are relatively inexpensive, have an appropriate half-life length for surgical prophylaxis, and are effective against most bacterial species that cause puerperal pelvic infections. Dosing changes related to weight, surgery length, or blood loss are described in Chapter 18 (p. 295).
As noted, the overwhelming majority of women treated for postcesarean metritis have an adequate clinical response within 3 days. Cited earlier, Brumfield and coworkers (2000) found that metritis after cesarean delivery responded within 72 hours to appropriate treatment in 94 percent of cases. In a study from Parkland Hospital, Brown and colleagues (1999) found that only 1 in 650 women with postpartum metritis had fever that persisted for more than 5 days despite adequate antimicrobial therapy. That said, a number of infection-related complications are responsible for persistent fever, and a thorough investigation should be pursued for any woman who fails to respond to antimicrobials. Relatively common are wound infections localized above the level of the abdominal fascia. Occasionally, these infections are from an extension of a uterine infection.
The incidence of postcesarean surgical site infections varies significantly depending on the population of women studied and the degree to which postdischarge evaluations are included. With a 2- to 3-day hospitalization postcesarean delivery, the vast majority of wound infections become symptomatic after discharge. For example, Op⊘ien and coworkers (2007) reported a surgical site infection rate of 8.9 percent within 30 days after cesarean delivery, but only 1.8 percent of these were diagnosed prior to patient discharge. Likewise, analyzing data from the Scottish Surveillance of Healthcare Associated Infection Programme, Reilly and colleagues (2006) found that 1.2 percent of women undergoing cesarean delivery between 2002 and 2004 had surgical site infections when no postdischarge surveillance was performed. This contrasted with an infection rate of 12.2 percent in women who did have posthospitalization surveillance. As noted above, the use of prophylactic antibiotics reduces the risk, and contemporary United States reports identify a 4- to 5-percent incidence of wound infection when antibiotics are universally given (Sullivan, 2007; Thigpen 2005).
Wound infections include superficial skin and soft tissue infections, incisional abscesses, and deep tissue infections that extend below the abdominal fascia and involve pelvic organs. Definitions for these are listed in Table 32-3. Known risk factors for wound infection include those listed in Table 32-4. As discussed in Chapter 2 (p. 24), the use of subcutaneous drains at time of initial wound closure does not decrease the risk for subsequent infections, even in obese women (Hellums, 2007; Ramsey, 2005).
Superficial incisional Involves only skin and subcutaneous tissue of the incision Develops within 30 days of surgical procedure Features at least one of the following: Purulent drainage from the superficial incision Bacteria in culture obtained aseptically from fluid or tissue from the superficial incision Incision deliberately opened by surgeon and is culture positive (or not cultured) and patient has at least one of the following incisional signs or symptoms: Tenderness or pain Heat or redness Localized swelling SSI diagnosis made by surgeon or attending physician Stitch abscesses are not included in this category Diagnosis of “cellulitis,” by itself, does not meet criterion for SSI |
Deep incisional Involves the deep soft tissues (muscle and fascia) of the incision Develops within 30 days of surgical procedure Features at least one of the following: Purulent drainage from deep incision of surgical site (but not organ or space component) Deep incision that spontaneously dehisces or is deliberately opened by a surgeon and is culture-positive (or not cultured) and patient has at least one of the following signs or symptoms: Temperature ≥38°C (100.4°F) Localized pain or tenderness Abscess or other infection found by reoperation, histopathology, or radiology |
Organ/space Involves any body part that was opened or manipulated during the operative procedure, excluding the skin incision, fascia, or muscle layers Develops within 30 days of the surgical procedure Features at least one of the following: Purulent drainage from a drain placed through a stab wound into the organ/space Bacteria obtained aseptically from tissue or fluid in that organ/space Abscess found by reoperation, histopathology, or radiology Vaginal cuff infection with purulence, abscess, and/or positive tissue or fluid culture is included in this category |
| Smoker |
| Obesity |
| Hypertension |
| Diabetes mellitus |
| Perioperative anemia |
| Excessive blood loss |
| Intraoperative hypothermia |
| Lower socioeconomic status |
| Immunocompromised patient |
| Intrapartum chorioamnionitis |
| Prolonged surgical procedure |
| Hematoma or seroma formation |
| Foreign body placement (catheter, drain, etc.) |
For women being treated for postoperative metritis, failure to respond to appropriate antibiotic coverage raises suspicion for an evolving wound infection. Typically, however, wound infections develop later and around the fifth or sixth postoperative day. Erythema and induration are usually present to some degree, and purulent drainage indicates at least an incisional abscess (Fig. 32-2). Fever occurs variably with localized wound infections but almost always accompanies deep tissue infections. Organisms causing these infections usually are the same as those isolated from amnionic fluid at the time of cesarean delivery, but hospital-acquired pathogens must be considered (Emmons, 1988; Gilstrap, 1979).
FIGURE 32-2
This patient presented 8 days postoperatively following cesarean delivery with fever and incisional drainage from one corner. Skin and subcutaneous tissues around the incision were mildly erythematous and edematous. During gentle exploration of the draining corner using a cotton swab, the skin and subcutaneous layers along a major portion of the wound spontaneously dehisced and revealed a larger incisional abscess. After initiation of intravenous antibiotics, the wound was subsequently debrided in the operating room.
Periincisional cellulitis without evidence of abscess may be adequately treated with antibiotics and close observation. Oral antibiotics and outpatient therapy are often appropriate, provided there are no systemic signs or symptoms. With treatment, the patient can return for a surveillance visit in 24 to 48 hours to ensure improvement. Wounds in which an abscess collection is not initially suspected may eventually suppurate, so close observation is mandatory.
Any wound with an obvious abscess collection requires prompt drainage (Fig. 32-3). Parenteral broad-spectrum antibiotics are also initiated, and those in Table 32-2 are suitable. Surgical drainage includes all purulent material, including pus loculations. Cultures are typically taken and may help to direct subsequent therapy, particularly in women who fail to respond to an empiric antimicrobial regimen. In most cases, the entire length of the wound must be explored to the level of the fascia. Careful inspection for fascial integrity is paramount when the wound is first opened. If the fascial layer is intact, then debridement of the subcutaneous layer and local wound care is appropriate. In some cases, inspection and debridement are initially carried out in the operating room because extensive debridement and exploration requires substantial anesthesia.
FIGURE 32-3
A. This patient presented with fever and incisional pain 7 days after cesarean delivery. Her Pfannenstiel incision showed minimal erythema, but a large bulging erythematous area was noted between the incision and umbilicus. B. Computed tomography was obtained and showed a 12.3 × 6.5 cm fluid collection with indistinct margins (asterisk). Evacuation confirmed an infected hematoma beneath the anterior rectus sheath. B = bladder; U = uterus.
After vigorous debridement of all necrotic tissue and drainage of purulent material, the wound cavity is packed with moistened sterile gauze. This dressing is changed at least daily, and preferably twice daily, with appropriate debridement at each dressing change.
It is controversial whether to use antiseptic agents such as hydrogen peroxide, iodine, or Dakin solution, or to use sterile saline. Some clinicians feel strongly about using diluted hydrogen peroxide solutions or iodine solutions for debridement if gross infection is evident. Recall that both of these solutions are also damaging to healthy tissue. Dakin solution—sodium hypochlorite—not only is bactericidal but is known to promote granulation tissue.
Once infection has cleared, wounds ultimately can heal by secondary intention or be reapproximated by delayed primary closure. With healing by secondary intention, a wound gradually adds granulation tissue from its base and sides to close the defect (Fig. 32-4). This may take several weeks to months depending on the size and depth of the wound.
In contrast, delayed primary closure is aesthetically preferable and results in significantly faster healing times (Wechter, 2005). In this method of management, local wound care is carried out until healthy, pink granulation is noted—typically 4 to 6 days after the initial debridement. At this point, delayed primary closure can be accomplished. Nonabsorbable suture, usually polypropylene or nylon, is placed in interrupted fashion across the length of the wound such that both the subcutaneous tissue and skin edges are apposed. Some surgeons use retention sutures to avoid undue pressure on the skin from the suture. An inexpensive method to accomplish the same goal is to use short segments of red rubber catheter and run one end of the suture through the tubing prior to tying the knot (Fig. 32-5). With or without this bridge, the knot should be tied in such a manner that the skin edges are not strangulated. These sutures can be removed on or around postprocedural day 10. Skin closure strips (Steri-Strips) can be applied at that time.
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