Post-operative fever is a temperature of ≥38°C for 2 consecutive days after surgery that can be caused by an inflammatory response or infection. The pathophysiology involves cytokine release triggering heat production in the hypothalamus. Causes include infections like surgical site infections or pneumonia, and non-infectious factors like medications, DVT, or atelectasis. Differential diagnosis depends on fever onset—immediate, acute within a week, subacute 1-4 weeks, or delayed after a month. Evaluation involves examining the surgical site, labs, imaging, and treating any identified infections.
2. WHAT IS POST OPERATIVE FEVER ?
•Any fever i.e., temperature of ≥
38 degree Celsius for 2
consecutive days after surgery
caused by inflammatory
response related to the surgery
that occurs from the time of
surgery to more than one month.
3. PATHOPHYSIOLOGY OF POST-OP
FEVER
Manifestation of cytokine release/response
By monocyte, macrophages, endothelial cells
i.e; IL-1, IL-6, TNF-alpha
Act on the hypothalamic endothelium
Stimulate production of PGE2 & cAMP release
cAMP acts as neurotransmitter & raises the
“set-point” => heat conservation & production
4. CAUSES OF POST-OP FEVER
• INFECTIOUS CAUSES
Surgical site infections
Pneumonia
UTI
Catheter infection
Sinusitis
Meningitis
Parotitis
Foreign body
• NON-IFECTIOUS CAUSES
Stress of surgery
Medications
Malignant
hyperthermia
Deep vein
thrombosis
Fat embolism
Transfusion
reactions
Atelectasis
5. DIFFERENTIAL DIAGNOSIS OF POST-
OPERATIVE FEVER
•Immediate Fever --- during surgery &
within hrs.
•Acute Fever -------- within first
week.
•Subacute Fever ----- 1- 4 weeks after
surgery.
•Delayed Fever ------ 1 month after
6. Onset in operating suite or within
hours after surgery
Medication reactions:
antibiotics, blood products,
malignant hyperthermia.
Necrotizing infection:
Clostridium, Group A β-hemo
strep.
Treatment: ABC, resuscitate,
7. ACUTE FEVER
Onset within 1st week after surgery
necrotizing infection (within 48hrs)
anastomotic leak (classically POD# 3 to 5)
Pulmonary embolism
MI
Pneumonia
Aspiration
UTI
Surgical site infection (SSI)
Other: acute gout, pancreatitis
8. Onset from 1 to 4 weeks after surgery
Surgical site infection
UTI
Line infection
Antibiotic-associated diarrhea
Febrile drug reactions
Thrombophlebitis
Sinusitis
9. Onset >1 month after surgery
Infection
Viral infections from blood
products
Surgical site infections
10. THE FIVE “W”
The Five “W” & timing of each
Wind (POD#1) atelectasis,
pneumonia
Water (POD#3) UTI, anastomotic
leak
Wound (POD#5) wound infection,
abscess
Walking (POD#7) DVT / PE
Wonder-drug or What did we do?
Many drugs cause fever, blood transfusions,
central lines we put in (line sepsis)
11.
12. ABCs
Resuscitate
Anesthesia record, operative note,
nursing report, flowchart
Physical examination:
Complete exam
Look at wounds - take off dressings
Look at drain output
Check IV sites, CV line, Foley, tubes
13. INVESTIGATIONS
If infection is suspected, following Lab tests should
be done order if concerned for infection:
CBC, sputum culture, urine complete,
Imaging:
CXR (for pneumonia)
Lower extremity venous duplex (for DVT)
CT scan (for abscess, leak, pancreatitis, PE)
14. Remove/replace sources of infection
Foley catheter, central lines, or
peripheral IV’s
Surgical debridement: Open, debride,
and drain infected wounds
If suspect pneumonia, bacteremia, UTI,
sepsis – start broad spectrum antibiotics,
piperacillin/tazocin and clindamycin.
Anticoagulation for DVT/PE
CT guided drainage of abscess
15. The 5 W’s
Think the worst and rule it out!
Necrotizing fasciitis must be
identified and treated aggressively