details about post-op fever by Dr. Nabarun Biswas

1. EVALUATION OF
POSTOPERATIVE PYREXIA
Dr. Nabarun Biswas
Registrar Surgery
MMCH

2. What we know
Immediate postoperative :
Metabolic response
Blood transfusion
Drug reaction
Thyroid storm
Malignant hyperthermia
Cause of post operative fever:
1st & 2nd POD:
Atelactesis

3. 3rd, 4th & 5th POD:
Chest infection
Phlebitis
UTI
Drain tube tract infection
5th, 6th & 7th POD:
Wound infection
Anastomotic leakage
Intra abdominal abscess
After 1st week:
DVT
Intra abdominal abscess
Cause of post operative fever:

4.  Introduction
 Predisposing factors
 Pathophysiology
 Differentials
 Evaluation
 Treatment
 Conclusion
What we are going to know

5. The postoperative period begins immediately after
surgery
The length of the post operative period is variable
Complications can occur in this period, one of such is
post operative pyrexia (fever)

6.  Fever is an elevation of body temperature that exceeds
the normal daily variation and occurs in conjunction with
an increase in the hypothalamic set point
◦ Normal body temperature range: 36.6°C-37.5°C
◦ 37.2°C @ 6am
◦ 37.7°C @ 4pm
Types of fever:
◦ Continuous (sustained)
◦ Intermittent
◦ Remittent
◦ Relapsing

8. Post operative pyrexia can be defined as a core
temperature >38°C on two consecutive post operative
days or >39°C on any one post operative day
 Axillary temperature < 0.5°C core temperature
Some causes of post operative pyrexia are self
limiting requiring only observation
Causes could be infectious and noninfectious

9. 1. Pre-operative fever
2. Extent of surgery –
major surgeries e.g. intrabdominal,
intrathoracic
3. Factors that increase the risk of infection :
e.g. Prolonged use of catheters, drains, prolonged
ETT , immunosuppression, prolonged immobilization
4. Medical co-morbidities:
obesity, chronic lung diseases, diabetes mellitus

10. Normal body temperature is primarily regulated
by Hypothalamus.
Infectious agents, microbial products (exotoxins and
endotoxins), damaged tissue, hypoxia and compliment
components  stimulate Macrophages, Endothelial cell
and the Immune system to release Pyrogenic Cytokines
(TNF, IL-1, IL-6, IFN).
These pyrogenic cytokines elevates hypothalamic set
point of temperature and body temperature raises

14. To differentiate post op pyrexia we should
consider the following:
1. The timing/ onset of the fever
2. The Surgical 7Ws menomic
Wind,
Water,
Wound,
Walk,
Wonder drug,
Withdrawal
Wonky gland

15. Timing
Immediate post-op pyrexia (<48 hourspost- op)
Acute post-op pyrexia (48 hours – 7days post op)
Subacute post-op pyrexia (7 days – 28days post op)
Delayed post-op pyrexia (after 28 dayspost op)

16. Surgery: Inflammatory response to tissue injury release
of pyrogenic cytokinesfever.
This fever is usually self-limiting resolving in
approximately 2 to 3 days.
Pre-existing medical conditions: Pre-op fever, Surgical
stress may also lead to the exacerbation of certain medical
conditions, for example, thyroid storm

17. Drug induced:
◦ Idiosyncratic reactions: classic examples include the
Malignant Hyperthermia from Inhaled Anaesthetics-
Halothane,Succinyl Choline
◦ Alterations in Thermoregulation: Antcholinergics
(↓sweating → ↓heatloss)
◦ Administration related: Phlebitis, Thrombophlebitis
◦ Direct pharmacologic action of the drug (drug
fever): e.g. heparin, hydralazine, phenytoin

18.  Blood transfusion reactions: Immune-mediated
Complications from surgery: Haematoma, Seroma,
Acute inflammatory reaction to sutures and prosthesis
used during surgery
Cardiovascular causes: Post-op MI, CVA, fat
embolism
Malaria: In Endemic regions, can occur anytime
Withdrawal from alcohol: May presentas
Delirium Tremens

19. Infectious causes of postop fever becomemore likely
when postop fever is discovered after 48 hours, specially
if ASA –above II, temp > 38.6 0c, WBC > 10,000/l, BUN >
15 mg/dl 3 or more present  bacterial infection is
100%
 UTI: urethral catheterization, and genitourinary
surgeries.
Pneumonia: ETT, prolonged ETT, patients with increased risk
of aspiration (use of NG tube, vomiting, depressed gag
reflex), atelectasis
Superficial thrombophlebitis: patients on intravenous
cannula.

20. Surgical site infections: usually superficial - wound
cellulitis.
There are, however, 2 organisms that can cause
fulminant SSI; can occur within 48 hours postop
◦ Group A streptococcal and
◦ Clostridial infections
Anastomotic leak
Deep venous thrombosis and PE
 Non-infectious causes of immediate postop pyrexia may also
cause fever in this period

21.  Deep vein thrombosis and/or pulmonary
embolus from prolonged immobility
Deep infections (Pelvic or abdominal abscess)
Pseudomembranous colitis
Infectious causes mentioned above (UTI,
pneumonia, SSI)

22.  Osteomyelitis
Viral infections related to blood products— CMV,
hepatitis, HIV
Parasitic infections—toxoplasmosis

23. Wind : Atelectasis (˂48hrs)
Water : UTI (48- 72hrs)
Walk : DVT/PE (3-5days)
Wound : Surgical site
infection (5- 10days)
Wonder drug : Antibiotics, heparin,
inhalational anaesthetic drugs,
anticonvulsants (Any TIME)
Withdrawal : Alcohol (delirium
tremens begin 72hrs after last
drink)
Wonky gland: Thyrotoxicosis
(thyroid storm) Adrenal
insufficiency

24. History
Consider if patient had fever pre-operatively
Respiratory: e.g.? Intubation? COPD, cough,
sputum, haemoptysis, chest pain, Difficulty
breathing
Cardiac: e.g. chest pain, palpitation, dizziness
Urinary: e.g. ?urethral catheterisation? How long?
dysuria, frequency, urgency, haematuria
GIT: e.g. Nausea, vomiting, diarrhoea,
abdominal pain, bleeding PR
Related to surgery: Surgical site pain
MSS: calf pain, pain at IV catheter site

25. Immunocompromised? or malnourished?
Co-morbidities: malignancy, hyperthyroidism,
alcohol addiction
Checklist:
◦ Onset, pattern, T-max of fever
◦ Anaesthetic Record for Medication
◦ Blood products administered during the
perioperative period?
◦ Input/output chart and types of stools

26. What is the Temperature?
Surgical Site – inspect and Take off any dressings,
discharge, rawness? Apposition? hyperaemia
undue tenderness, abnormal swelling, fluctuance
Drains, urethral catheter (cloudy, bloody)
Lines – e.g. IVC, CV line
Chest – Tachypnoea, consolidation, crepitation
Heart – murmurs, tachycardia

27. Abdomen – tenderness? Movement
with respiration?
Calf – Unilateral calf tenderness, peripheral
oedema
 Skin - rash, jaundice, petechiae, erythema,
hematoma, pressure sore
 Rash – toxic shock syndrome
 Petechiae – fat embolism

28. Depends on hhistory and examination finding:
–Urinalysis, Urine MSU m/c/s,
–Wound swab/ biopsy m/c/s
–MP
–Sputum m/c/s
–Blood Culture
–Aspirate m/c/s
– FBC, S.Cr, LFT
–CXR, abdominal USS, ECG, CT angiogram
–Doppler USS
–Others – specific to clinical suspicion

29. Management of postop pyrexia depends on the
probable cause
In general, early postop fever requires no
intervention if there are no inciting factors
Nursing care: exposure, tepid sponging,
temperature monitoring and charting
Antipyretics, Rehydration, Antiemetic

30. Atelectasis: Incentive Spirometry, Chest
Physiotherapy, semi-recumbent position
Infective causes:
Treat with empirical antibiotics while awaiting c/s
Remove/replace lines promptly if in tissue (IV
cannula, CV line – send tip for culture)
Timely removal of urethral catheter, drains
Drainage of abscess, seroma, haematoma
Debridement

31. Transfusion/Drug related - STOP transfusion, further
transfusion with washed cells if immunologically
mediated
Thromboembolic – Treat with anticoagulation
Malignant hyperthermia: IV Dantrolene Na,
Supportive Care
Note: increase in caloric and fluid requirement
following prolonged high grade fever due increase
in metabolism and insensible fluid loss

32. Postoperative pyrexia is a common
postoperative surgical complication
Fever may be infectious or non-infectious
Knowledge of differential diagnosis, and systematic
approach, helps in proper diagnosis and proper
management
When indicated antibiotics should be judiciously
used depending on the possible infectious cause

33. Referrences:
1. Bailey’s & Love, 27th edition
2. CSD, 14th edition
3. RCS manual, 4th edi
4. Sabiston, 19th edi
5. Some online journals