Discuss post operative pyrexia
- 1. Dr A. G Umolu Registrar Orthopaedics and Traumatology University of Benin Teaching Hospital
- 2. Introduction Predisposing factors Pathophysiology Differentials Evaluation Treatment Conclusion
- 3. The postoperative period begins immediately after surgery and ends with the first follow up visit It can also be said to terminate with the resolution of the surgical sequelae The length of the post operative period is variable Complications can occur in this period, one of such is post operative pyrexia (fever)
- 4. 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: ◦ Continuous (sustained) ◦ Intermittent ◦ Remittent ◦ Relapsing
- 6. Post operative pyrexia can be defined as a core temperature (aural/ rectal) >38°C on two consecutive post operative days or >39°C on any one post operative day Axillary temperature < 0.5°C core temperature Post operative pyrexia can be distressing to the patient & importantly a cause of great concern to the surgeon It may also be an indicator of a severe and life threatening underlying pathology The reported incidence varies but can be expected in about 13%- 14% of cases
- 7. Some causes of post operative pyrexia are self limiting requiring only observation In the same vein some are emergencies and early recognition and action is key to good outcome Causes could be infectious and non infectious, however ˂50% of post op pyrexia are caused by infections Magnitude of the fever does not indicate presence or absence of an infective cause Treatment depends on probable cause
- 8. Pre-operative fever Extent of surgery – major surgeries e.g. intrabdominal, intrathoracic Factors that increase the risk of infection e.g. prolonged 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 the Preoptic Anterior Hypothalamus. Infectious agents, microbial products (exotoxins and endotoxins), damaged tissue, hypoxia and compliment components, stimulate Macrophages, Endothelial cell and the ReticuloEndothelial system to release Pyrogenic Cytokines (TNF, IL-1, IL-6, IFN).
- 12. Spillage into the systemic circulation Hypothalamus: cytokines stimulate the cytokine receptors on hypothalamic endothelium leading to the synthesis of PGE2 Microbial toxins also directly stimulate the hypothalamic endothelium PGE2 raises the thermostatic set point in the hypothalamus to febrile levels. The vasomotor centre sends signals for heat conservation (vasoconstriction) and heat production (shivering).
- 14. Differentials for post op pyrexia can be considered as follows: 1. The timing/ onset of the fever 2. The Surgical 7Ws mnemonic ◦ Wind, Water, Wound, Walk, Wonder drug, Withdrawal and Wonky gland
- 15. The time frame/onset for fever occurrence is the most critical factor to consider when making a differential for postop pyrexia. 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)
- 16. Surgery: Inflammatory response to tissue injury from the release of pyrogenic cytokines. This fever is usually self-limiting resolving in approximately 2 to 3 days. The severity of fever is proportional to the degree of the metabolic response to trauma Pre-existing medical conditions: Pre-op fever, Surgical stress may also lead to the exacerbation of certain medical conditions, for example, thyroid storm or a gouty flare.
- 17. Drug induced: ◦ Idiosyncratic reactions: classic examples include the Neuroleptic Malignant Syndrome and 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. antibiotics, heparin, hydralazine, phenytoin ◦ hypersensitivity reactions: immunologically mediated
- 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 present as Delirium Tremens
- 19. Infectious causes of postop fever become more likely when postop fever is discovered after 48 hours 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 after orthopaedic surgery Viral infections related to blood products— CMV, hepatitis, HIV1, 2 Parasitic infections—toxoplasmosis Rarely, SSIs can occur in this period caused by indolent organisms, such as coagulase negative staphylococci
- 23. Wind : Atelectasis (˂48hrs) Water : UTI (48- 72hrs) Walk : DVT/PE (3-5days) Wound : 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, gout, alcohol addiction Charts: ◦ 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. Is patient hot to touch? 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, CVC 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 hx 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, E/U/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: ◦ Pneumonia : sputum mcs, chest xray ◦ Surgical site infection: wound swab/ biopsy, local wound care ◦ UTI : take m/c/s, change catheter/ site one if indicated Treat with empirical antibiotics while awaiting m/c/s), Remove/replace lines promptly if in tissue(IV cannula, CVC – 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, Discontinue Offending drug Thromboembolic – Treat with anticoagulation ◦ VTE prophylaxis and wearing of pneumatic stocking for prevention 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, as well as systematic approach, proves useful in narrowing down the diagnosis and instituting proper management When indicated antibiotics should be judiciously used depending on the possible infectious cause