Postoperative Fever

Postoperative fever occurs in up to two thirds of patients, and infection is the cause of fever in one third of cases.

Absent a fever, any hypotension, tachycardia, tachypnea, confusion, rigors, skin lesions, respiratory manifestations, oliguria, lactic acidosis, leukocytosis, leukopenia, immature neutrophils (i.e., bands >10%), or thrombocytopenia may indicate a workup for infection and immediate empirical therapy.

Postoperative Fever

Some infected patients do not become febrile and may be even be hypothermic. Hypothermic or euthermic patients may have a life-threatening infection. These include older patients, those with open abdominal wounds, or with ESLD or CRF, and patients taking anti-inflammatory or antipyretic drugs.

Fever, may have an noninfectious cause; therefore, fever does not equate with infection.

Postoperative Fever

Fever is common during the initial 72 hours following surgery and is usually noninfectious in origin (DVT, PTE, tissue ischemia or necrosis, adrenal insufficiency, drug fever, malignant hyperthermia, and acute allograft rejection).

Postoperative FeverImmediate —onset in the operating suite or within hours after surgery

Medications or blood products; trauma suffered prior to surgery or as part of surgery; infections that were present prior to surgery; and rarely malignant hyperthermia.

Drug fever is decidedly unusual in surgical patients and is a diagnosis of exclusion.

Drug fever in surgical ICUs is most often attributed to antimicrobial agents (e.g., vancomycin, β-lactams), and anticonvulsants (especially phenytoin).

Postoperative FeverImmediate —onset in the operating suite or within hours after surgery

The initial clinical signs (ie, hypercarbia) of malignant hyperthermia typically present within 30 minutes following the administration of a triggering agent (eg, inhaled anesthetics, succinylcholine), but have been reported later in the operative course and also following cessation of anesthesia.

Fever due to the trauma of surgery usually resolves within two to three days. Fever caused by severe head trauma can be persistent and may resolve gradually over days or even weeks.

Postoperative FeverAcute — onset within the first week after surgery

Nosocomial infections are common during this period.

pneumonia : Ventilation, depressed mental status or gag reflex due to anesthesia and analgesia

UTI : urethral catheters, GU procedures

Postoperative FeverAcute — onset within the first week after surgery

SSI most often presents in the subacute period. However, clostridial or streptococcal SSIs can manifest as fever within the first 72 hours of surgery.

Catheter exit site infections and bacteremia associated with intravascular catheters also tend to occur subacutely but should be considered as sources of fever in any patient with a catheter in place.

Postoperative FeverAcute — onset within the first week after surgery

Acute fever can also be caused by noninfectious conditions. (Pancreatitis, MI, PTE, DVT, alcohol withdrawal, and acute gout).

Postoperative FeverSubacute — onset from one to four weeks following surgery

DVT, PTE, drug fever (Beta-lactams antibiotics and sulfa-containing products, H2-blockers, procainamide, phenytoin, heparin), SSIs, nosocomial infections (device-related infections due to bacteria and fungi include intravascular catheter-related infection with or without bacteremia, VAP, UTI, sinusitis, AAD, AAC, )

Postoperative FeverDelayed — onset more than one month after surgery

Most due to infection

infections from blood products (CMV, hepatitis viruses, HIV, toxoplasmosis, babesiosis, malariae)

SSIs due to more indolent microorganisms (eg, CoNS)

delayed cellulitis when surgery has disrupted venous or lymphatic drainage

Infective endocarditis due to perioperative bacteremia

Postoperative FeverCONSIDERATIONS FOLLOWING SPECIFIC SURGERIES

Cardiothoracic surgery Neurosurgery Vascular surgery Abdominal surgery Obstetric and gynecologic surgery Urologic surgery Orthopedic surgery Transplantation 

Postoperative FeverCXR, U/A, U/C, B/C are not indicated for all postoperative patients with fever.

The need for laboratory testing should be determined by the findings of a careful history and physical examination.

The febrile postoperative patient should be evaluated systematically.

In evaluation, type of surgery performed, patient’s immune status, underlying primary disease process, duration of hospital stay, and epidemiology of hospital infections should be considered.

Postoperative Fever

Evaluation involves studying the six Ws: wind (lungs), wound, water (urinary tract), waste (lower GI tract), what did we do? (medications, blood products, and intravascular, urethral, nasal, and abdominal catheters) , and walker (e.g., thrombosis).

Postoperative Fever

* Studies should be ordered based upon the patient evaluation; no test is mandatory to obtain.

Studies should be ordered based upon the patient evaluation; no test is mandatory to obtain.

Urinalysis and culture

Sputum gram stain and culture

Blood culture (from catheters and peripherally - minimum of two)

Wound culture

Complete blood count with differential

Chest radiograph

Additional blood or radiographic studies might be indicated by specific findings. As examples, abdominal pain might indicate the need for blood tests for hepatic and pancreatic enzymes or abdominal CT scanning; unilateral leg edema might indicate the need for ultrasound to rule out DVT.

* Studies should be ordered based upon the patient evaluation; no test is mandatory to obtain.

Postoperative FeverAny unnecessary treatments, including medications and catheters, should be discontinued in patients with postoperative fever.

It is probably appropriate to suppress the fever in most patients with one or two days of scheduled acetaminophen to minimize patient discomfort and the physiologic stress and metabolic demands of fever and shivering. This approach is unlikely to mask a significant pathologic condition.

Additional treatment depends upon the cause of the fever.

Postoperative Fever Rx

Patients who have undergone major surgery and are receiving intensive care and patients with hemodynamic instability generally should be treated empirically with broad-spectrum antibiotics after cultures have been obtained.

Postoperative Fever Empiric Rx

Postoperative FeverNosocomial pathogens are often resistant to many antimicrobials; hospital antibiograms can be useful for selecting an appropriate broad-spectrum regimen.

If a source of fever is not apparent and blood cultures show no growth after 48 hours, then discontinuation of antimicrobials should be seriously considered.

Postoperative Fever

If a site of infection is identified and/or cultures are positive, the broad-spectrum regimen should be focused to cover the probable or known causative organism(s).

Antimicrobial treatment beyond the empiric period of 48 hours should be reserved for patients in whom an infection has been identified.

Gram stain findings and hospital antibiograms can be used to guide empiric antimicrobial selection, but definitive treatment should be based upon antimicrobial susceptibility results from cultured organisms.

SSIs

SSIs

SSIs

SSIsIn diagnosing SSIs, the physical appearance of the incision probably provides the most reliable information. Local signs of pain, swelling, erythema, and purulent drainage are usually present.

Flat, erythematous changes can occur around or near a surgical incision during the first week without swelling or wound drainage. Most resolve without any treatment, including antibiotics. The cause is unknown but may relate to tape sensitivity or to other local tissue insult not involving bacteria.

SSIsFever or systemic signs during the first several days after surgery should be followed by direct examination of the wound to rule outsigns suggestive of streptococcal or clostridial infection but should not otherwise cause further manipulation of the wound. Patients with an early infection due to streptococci or clostridia have wound drainage with the responsible organisms present on Gram stain. WBCs may not be evident in most clostridial and some early streptococcal infections.

SSIsA common practice, is to open all infected wounds. If there is minimal surrounding evidence of invasive infection (< 5 cm of erythema and induration), and if the patient has minimal systemic signs of infection (T< 38.5C and PR<1 00 beats/min), antibiotics are unnecessary. Because incision and drainage of superficial abscesses rarely causes bacteremia, antibiotics are not needed.

For patients with T > 38.5C or PR> 100, a short course of antibiotics, usually for a duration of 24–48 h, may be indicated. The antibiotic choice is usually empirical but can be supported by findings of Gram stain and results of culture of the wound contents.

SSIsSSIs that occur after an operation on the intestinal tract or female genitalia have a high probability of having a mixed gram-positive and gram-negative flora with both facultative and anaerobic organisms.

If the operation was a clean procedure that did not enter the intestinal or genital tracts, S. aureus (including MRSA) and streptococcal species are the most common organisms.

Because incisions in the axilla have a significant recovery of gram-negative organisms and incisions in the perineum have a higher incidence of gram-negative organisms and anaerobes, antibiotic choices should be made accordingly.

SSIs

SSIs