Page 828 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

CHAPTER 63: Persistent Fever 559

■ URINARY TRACT INFECTION the critically ill patient, it is seldom recognized as the source of fever.

Urine cultures are almost universally obtained during the evaluation Although computed tomography is the gold standard for the diagno-
sis of sinusitis, its utility in the day-to-day management of patients is
of fever in a critically ill patient regardless of patient age, gender, and
duration of catheter placement. However, urinary tract infections in limited because of difficulties in transporting critically ill patients to
the radiology suite. Ultrasonography of the maxillary sinuses is not as
the ICU occur almost exclusively in patients who have had indwell-
ing urinary catheters for a long duration and the infections occur sensitive as CT, but it is very specific (~95%), easy to learn, noninvasive,
and repeatable.
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more frequently in females and in those patients who have received
patients, the incidence of urinary tract infections was estimated to be ■ CLOSTRIDIUM DIFFICILE COLITIS
prior antibiotics. In an 18-month retrospective study of 510 trauma
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only 16/1000 catheter days, and during the first 2 weeks of urinary In many ICUs, C difficile colitis has replaced methicillin-resis-
catheter use, urinary tract infection was found to be an unlikely cause tant Staphylococcus aureus (MRSA) as the most common hospital-
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of either fever or leukocytosis. 33 acquired infection. Most cases of antibiotic-associated diarrhea are
When clinically indicated, most ICU urinary cultures are obtained unrelated to C difficile, but the association of fever, abdominal pain,
from an indwelling catheter because very few critically ill patients are or leukocytosis with diarrhea should suggest the diagnosis. In those
candidates for clean catch, midstream specimens. When obtaining patients who have received antibiotics within the past 30 days, up to
cultures from an indwelling catheter, it is paramount to adequately three individual stool specimens may be required to confirm a posi-
sterilize of the rubber port prior to sampling and to promptly process tive toxin assay. 47
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the specimen in less than 1 hour to prevent bacterial proliferation. ■
Cultures should never be obtained from a collection bag. A better idea ACALCULOUS CHOLECYSTITIS
is to obtain the culture from an “in-and-out” straight catheterization Acalculous cholecystitis is a complication of critical illness that
because it avoids contamination of the specimen by bacteria adherent when it is untreated has a high mortality. Increased lithogenicity of
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to the indwelling urinary catheter. In rare cases, an ultrasound-guided bile and ischemia of the gallbladder wall leads to biliary stasis and
suprapubic tap can be obtained to avoid contamination from the highly the formation of bile salt sludge. Secondary infection and gangrene
colonized distal urethra. of the gallbladder are common sequelae. Acalculous cholecystitis
■ PNEUMONIA is most commonly observed among patients with sepsis, severe
trauma, or burns. The diagnosis should be suspected in any critically
In a retrospective review of patients undergoing major gynecologic ill patient with fever and right upper quadrant pain or tenderness.
surgery, 80% of patients who developed pneumonia had symptoms sug- Abdominal ultrasound and computed tomography are the most
gestive of the diagnosis, whereas obtaining a routine chest x-ray on useful diagnostic tests. Gallbladder distension, thickening of the
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all febrile patients yielded a finding of pneumonia in only 9% of cases. gallbladder wall, presence of pericholecystic fluid, and intraluminal
These data would suggest that chest radiography for the evaluation of slugging are highly suggestive of the diagnosis. Although hepatobi-
fever in nonintubated post-op patients should be reserved for patients liary iminodiacetic scintigraphy (HIDA scan) is often used in the
with signs and symptoms of pneumonia. evaluation of calculous cholecystitis, its negative predictive value for
Although the performance of routine daily chest x-rays on stable, acalculous cholecystitis has been reported to be poor (<25%) when
nonintubated patients in the ICU has a low diagnostic yield for the disease is suspected. 49
The incidence of ■
pathology, it is often appropriate to obtain an on-demand chest x-ray
in a critically ill, ventilated patient with fever. 35,36 SURGICAL SITE INFECTION
ventilator-associated pneumonia (VAP) has been reported to range The risk of surgical site infections (SSI) among postoperative inpa-
from 5% to 67% among mechanically ventilated patients with an tients ranges from 2% to 5%, while 75% of postoperative deaths are
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attributable mortality of up to 10%. In practice, the diagnosis is directly attributable to SSIs. When fever occurs more than 96 hours
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most often made using readily available clinical variables (eg, char- postoperatively, infection is the likely cause. A myriad of factors
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acterization of secretions, chest x-ray appearance, body temperature, impact the risk of SSIs, for example, the anatomic location of the sur-
ratio). gery (eg, facial wounds less commonly become infected), the degree of
leukocyte count, culture, and measurement of the Pa O 2 /Fi O 2
However, it is clear that many intubated patients who meet these clin- contamination of the surgical site, quality of the sterile technique, prior
ical criteria do not have VAP. Compared to a simple tracheal aspirate surgical trauma at the operative site, use of prophylactic antibiotics,
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and culture, the use of invasive techniques, such as bronchoalveolar the length of time required to achieve hemostasis, and the presence of
lavage, to definitively establish the diagnosis of VAP does not appear preexisting comorbidities. SSIs may involve superficial skin structures
to reduce the use of antibiotics nor does it appear to improve clini- or deeper subcutaneous tissues, organs, or implanted material. Empiric
cal outcomes. The preferred approach when VAP is suspected is to antibiotics are usually not as effective for management as is surgical
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initiate empiric broad-spectrum antibiotics using existing guidelines drainage. Many SSIs are preventable. The Centers for Disease Controls
followed by rapid de-escalation of broad-spectrum antibiotics based has published a toolkit for hospitals to use to reduce SSIs. Use of
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on culture results. 42 appropriate antibiotic prophylaxis, preoperative control of remote
■ SINUSITIS infections, proper skin prepping, maintenance of normothermia post-
operatively, proper wound dressings, and daily probing of the wound
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Most ICU patients will at some point have an endotracheal tube, a with a cotton-tipped applicator between loosely applied staples are
nasogastric tube, or a nasotracheal suctioning device. These indwell- associated with a reduced risk of SSI.
ing tubes can cause mucosal trauma, introduce bacteria, and promote
biofilm formation all of which increase the likelihood of infection and SELECTED NONINFECTIOUS CAUSES
fever. Within 1 week of nasotracheal intubation and nasogastric tube OF FEVER AND HYPERTHERMIA
placement, approximately 1/3 of patients will have purulent maxillary
sinusitis, a rate approximately fourfold greater than that associated with Although approximately half of febrile patients in the ICU will have a
oral placement. In one prospective study of febrile intubated patients, noninfectious cause of fever, early in the clinical course of a patient, it
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sinusitis was determined to be the sole cause or a contributing cause of may be difficult or even impossible for a treating physician to exclude an
fever in 30%. Because sinusitis is rarely associated with symptoms in infectious etiology and thus to avoid obtaining appropriate cultures and
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