1. Post Operative Fever Tad Kim, M.D. UF Surgery tad.kim@surgery.ufl.edu (c) 682-3793; (p) 413-3222

2. Post Operative Fever Overview Definition & Pathophysiology Differential Diagnosis –The five “W” –Modified approach to DDx Initial assessment and work-up Management Cases

3. Post Operative Fever Definition & Pathophysiology Fever is temp ≥ 38 degrees Celsius Manifestation of cytokine release/response –By monocyte, macrophages, endothelial cells –IL-1, IL-6, TNF-alpha, IFN-gamma –Act on the hypothalamic endothelium –Stimulate produx of PGE2 & cAMP release –cAMP acts as neurotransmitter & raises the “set-point” => heat conservation & production

4. Post Operative Fever Differential Diagnosis The Five “W” & timing of each Wind (POD#1)atelectasis, pneumonia Water (POD#3)UTI, anastomotic leak Wound (POD#5)wound infex, 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)

5. Post Operative Fever Differential Diagnosis Five W’s are a guide for the most common But also learn to think worst-case scenario –“What can kill this patient if I miss the dx?” In general, early fever is not infectious with one critical exception: Necrotizing fasciitis or soft tissue infection Most early post-op fever resolves w/o tx –Simply a reaction/response to the surgery Fever occuring later: more likely infectious

6. Post Operative Fever DDx – Modified Approach Immediate fever – onset in OR or hrs after Killers: –necrotizing infection (can kill rapidly) Clostridium perfringens, Group A β-hemo strep Tx: ABC, Resusc, Pen G, surgical debridement –malignant hyperthermia Tx: ABC, Resusc, rapid cooling, IV dantrolene Other: Allergic rxn (to abx) or transfusion Look for hypotension, rash Tx: Stop the offending agent

7. Post Operative Fever DDx – Modified Approach Acute fever– within first week after surgery In addition to five W’s, think of these: Killers: –necrotizing infection (within 48hrs) –anastomotic leak (classically POD# 3 to 5) new abd pain, distension, peritoneal signs fever, tachycardia, hypotension –pulmonary embolism or MI (can p/w fever) Other: VAP, aspiration, nosocomial infex, EtOH withdrawal (day 3), acute gout

8. Post Operative Fever DDx – Modified Approach Subacute/delayed fever – after ~5days post-op, infectious etiology is more likely –#1: Wound infection (40%) –#2: UTI (29%) especially if indwelling Foley –#3: Pneumonia (12%) if on vent or COPD –Also think of: C.dif colitis, line sepsis & bacteremia, intra-abdominal abscess –Rarer: sinusitis, meningitis, peri-rectal abscess, acalculous cholecystitis, parotitis –Weeks out: endocarditis, infected prostheses

9. Post Operative Fever Initial Assessment If called for fever, get to the bedside, get the nurse/flowsheet and ABC with vitals Obtain a history or use the AMPLE format –Type of surgery, meds or blood given, other symptoms (rash, cough, dyspnea, chest pain, dysuria, leg swelling, painful IV site, abd pain) Physical: –#1 check the wound or surgical site –#2 lung sounds, heart/abd/extremity exam –#3 check IV sites, central line, Foley, tubes

10. Post Operative Fever Work-Up Labs if concerned about infection: –CBC w diff, Sputum Cx, UCx, Blood Cx x2 –Lumbar puncture (if AMS, neck pain, fever) –C.dif toxin assay –STAT gram stain if suspect necrotizing infex Imaging: –CXR (for pneumonia) –Lower extremity venous duplex (for DVT) –CT scan (for abscess, leak; or PE protocol) –RUQ ultrasound (if suspect cholecystitis)

11. Post Operative Fever Management Remove/replace sources of infection –Foley catheter, central lines, or peripheral IV’s –Open, debride, and drain infected wounds Antibiotics not indicated for wound infex unless associated cellulitis Tylenol 10mg/kg (ped) or 650mg po x1 If suspect pneumonia, bacteremia, UTI, sepsis – start broad spectrum antibiotics

12. Post Operative Fever Case 1 58yo man 5hrs after bilateral total knee arthroplasty. Temp of 38.7 C Only c/o knee pain controlled w meds On no antibiotics, taking home meds VS: Pulse 90, BP 130/70, O2 sat: 99% Mild serosanguinous drainage from knees No Foley or central lines, WBC 7 (normal) What do you do?

13. Post Operative Fever Case 1 What do you do? –A. Urine culture –B. Blood, urine cultures & CXR –C. Blood, urine cultures & vancomycin –D. Observation only

14. Post Operative Fever Case 2 65yo obese, diabetic female 5hrs s/p open chol’y for gangrenous cholecystitis. Called with T 40.0 C, tachycardia, abd pain Sx: Altered mentation, abd pain VS: P 140, BP 88/50, O2 Sat 94% PE: Wound is blistered, +crepitus, sub-Q gas & dirty, dishwater drainage Gram stain of fluid shows gram pos rods

15. Post Operative Fever Case 2 What is the diagnosis? –A. Cellulitis –B. Diffuse peritonitis –C. Necrotizing fasciitis –D. Uncomplicated post operative fever What is the organism on gram stain? –A. Group A strep –B. MRSA –C. Clostridium perfringens –D. Enterococcus

16. Post Operative Fever Case 2 Lessons Necrotizing fasciitis –Type I: Polymicrobial with aerobes/anaerobes usu. occurs after surgery, in DM or PVOD –Type II: Monomicrobial 2ndary to Group A strep, Strep pyogenes –MRSA is becoming more common for Type II ABC, ?intubate, 2 large IV, resuscitate Early Pen G + Broad-spectrum antibiotics Early surgical debridement –Mortality is 100% with antibiotics alone

17. Post Operative Fever Case 3 61yo F w rheumatoid arthritis on methotrexate undergoes left total hip. Has Foley catheter postoperatively. Fever of 38.1 C on POD#1, Foley is removed. Then has fever of 38.5 C on POD#4. She has been ambulating, using incentive spirometry, O2 Sats and vitals are normal Wound is clean

18. Post Operative Fever Case 3 What is the most likely diagnosis? –A. Deep venous thrombosis –B. Urinary tract infection –C. Superficial wound infection –D. Prosthesis infection

19. Post Operative Fever Take Home Points Know the five W’s as a rough guide for most common causes & timing Learn to think of what can kill the patient Also think: “what did we do to cause this?” Targeted H&P / labs / imaging to rule out the killers, then confirm most likely cause –Should have a working diagnosis before labs Know the dx & treatment of ‘nec fasciitis’