Post op pyrexia

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: 1 st & 2 nd POD: Atelactesis

3. 3 rd , 4 th & 5 th POD: Chest infection Phlebitis UTI Drain tube tract infection 5 th , 6 th & 7 th POD: Wound infection Anastomotic leakage Intra abdominal abscess After 1 st 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

7. 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

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

9. 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

10. To differentiate post op pyrexia we should consider the following : The timing/ onset of the fever The Surgical 7Ws me no mic Wind , Water, Wound, Walk, Wonder drug , Withdrawal Wonky gland

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

12.  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

13.  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

14.  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 present as Delirium Tremens

15. Infectious causes of postop fever become more likely when postop fever is discovered after 48 hours , specially if ASA –above II, temp > 38.6 c, 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.

16.  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

17.  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)

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

19.  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

20. 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

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

22.  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

23.  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

24. Depends on h history 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

25.  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

26.  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

27.  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

28.  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

29. Referrences : Bailey’s & Love, 27 th edition CSD, 14 th edition RCS manual, 4 th edi Sabiston , 19 th edi Some online journals