Fever in the ICU

1. Fever in the ICU J V Peter MD, DNB (Med), FRACP, Medical ICU Christian Medical College & Hospital

2. Introduction

3. Introduction • Fever is a common problem in the ICU • Could be due to infectious and non-infectious causes • Objective is to review a rational approach to the management of fever in ICU patients

4. What is fever? • Fever is a co-ordinated neuro endocrine, autonomic and behavioral response that is adaptive, and an essential part of the acute-phase response to immune stimulus or tissue injury • Co-ordinated by the hypothalamus • Neural input from peripheral thermoreceptors • Humoral cues from inflammation or infection

5. Benefits of fever • Enhances parameters of immune function • Improves antibody production • Activates T-cells • Produces cytokines • Enhances neutrophil and macrophage function

6. Benefits of fever - translated? • Hot baths for malaria fever for treatment of syphilis • Positive correlation between maximum temperature on the day of bacteremia and survival • Temperature > 38 °C improved survival in patients with SBP • In children with chicken pox, treatment with acetaminophen increased time to crusting of skin lesions

7. The downside of fever • Increased cardiac output • Increased oxygen consumption • Increased carbon-di-oxide production • Increased basal metabolic rate

8. The downside of fever-translated • Poorer neurological outcomes in patients with stroke and traumatic brain injury who manifest temperature • Fever poorly tolerated in patients with reduced cardio-respiratory reserve • Maternal fever cause of fetal malformations as well as spontaneous abortions

9. How to measure temperature in the critically ill patient?

10. With a thermometer of course !

11. Measurement of temperature • Peripheral temperature measurements • Measured in the outer 1.6 mm of skin or mucus membranes • Considered unreliable as influenced by environmental temperatures, mouth breathing etc. • Examples – oral temperature, axillary, skin temperature • Core temperature measurements • Not influenced by external factors • More accurately reflects temperature in the internal organs • Examples – pulmonary, rectal, esophageal, urinary, tympanic

12. Measurement of temperature • Optimal site • Pulmonary – but invasive, need equipment • Alternatives • Tympanic – easy but can be off by even 2O • Urinary – good alternative • Rectal – uncomfortable • Oesophageal

13. When do we say “fever” in the ICU patient?

14. What is normal? • Normal temperature • 98.2O F (36.8OC) • Diurnal variations of temperature with evening rise up to 100O F (37.8O C)

15. So when do we get worried in the ICU? • Society of Critical Care Medicine (SCCM) and Infectious diseases society of America recommend investigations in the ICU if temperature is above • 101O F (38.3OC)

16. Approach to fever in the ICU

17. Approach to fever in ICU • What are the causes of fever in ICU • How do I act when I am see a temperature spike? • What investigations do I send? • How do I treat the fever?

18. Approach to fever Patient who comes in with a febrile illness Cause of fever need to be ascertained Patient in the ICU develops fever What is causing this fever?

19. Patient presenting to ICU with fever Patient with an obvious focus of infection Where is the focus? Acute un-differentiated fever What is causing this fever?

20. The obvious focus • Community acquired pneumonia • Acute CNS infection • Urinary tract infection • Abdominal focus of infection • Wound infection / Pus collections • Trauma with infection

21. The obvious focus • And why do they come to the ICU • Ventilatory support – respiratory failure – pneumonia • Hemodynamic support – shock • Renal replacement therapy – renal failure, severe acidosis • Monitoring, Neurological dysfunction, Hematologic

22. Approach to fever Patients presenting with a febrile illness Patient developing fever in the ICU Is there a focus of infection? Acute undifferentiated fever √

23. Acute undifferentiated fever • Where no specific focus identified • Look for specific clues to guide in the diagnosis

24. Acute undifferentiated fever • Fever with thrombocytopenia • Fever with hepato-renal dysfunction • Fever with pulmonary renal syndrome • Fever with altered sensorium

25. Fever with thrombocytopenia • Fever with thrombocytopenia • Malaria (notably falciparum) • Dengue • Leptospirosis • Rickettsial infections • Viral fevers

26. Fever with hepato-renal dysfunction • Fever with hepato-renal dysfunction • Malaria (falciparum) • Leptospirosis • Scrub typhus • Fulminant hepatic failure with hepatorenal

27. Fever with pulmonary-renal dysfunction • Fever with pulmonary-renal dysfunction • Malaria (falciparum) • Leptospirosis • Scrub typhus • Hantavirus infection • Severe legionella / pneumococcal pneumonia

28. Fever with altered sensorium • Fever with altered sensorium • Malaria – cerebral malaria • Encephalitis • Meningitis • Typhoid fever • Septic encephalopathy • Brain abscess

29. Approach to fever Patients presenting with a febrile illness Patient developing fever in the ICU Is there a focus of infection? Acute undifferentiated fever √ √

30. Patient developing fever in the ICU Infectious causes Where is the focus? Non-infective causes What is causing this fever?

31. Infectious causes of fever whilst in ICU • Ventilator associated pneumonia • Catheter related blood stream infections • Urosepsis • Intra-abdominal infections • Sinus infections • Diarrhoea

32. Infectious causes of fever whilst in ICU • Fungal infections including candidemia • Surgical wound infections • Acalculous cholecystitis • Endocarditis • Meningitis

33. Non-infectious causes of fever in ICU

34. Summary of approach to fever in ICU Patients presenting with a febrile illness Patient developing fever in the ICU Is there a focus of infection? Infective Causes Acute undifferentiated fever Non-infective Causes

35. Approach to fever in ICU • What are the causes of fever in ICU √ • How do I act when I am see a temperature spike?

36. How do I act when there is a temperature spike?

37. Should I be worried? YES In an immunocompromised patient If hemodynamic instability Decreasing UOP Increasing lactate Worsening conscious state Falling platelet counts Worsening coagulopathy NO Small spike No hemodynamic instability Carefully examine clinically for an obvious focus of infection One temperature spike

38. What investigations to send?

39. What investigations should I send? • Bloods – counts, procalcitonin • Imaging – CXR, Scans as indicated (abdomen, sinus, CT brain) • Cultures as appropriate – ETA, BAL, Urine, Blood cultures (peripheral and through lines), cultures from pus, wound etc, Stool for clostridium

40. What investigations should I send? • Assess if lines are “old” and if there is any evidence of line sepsis - re-site line if indicated • Change urinary catheter • May need NG change – if sinus infection suspected

41. What investigations should I send? • Do not forget about non-infective causes • Acute Lung injury/ARDS, Aspiration • Deep venous thrombosis, thrombophlebitis • Drug fever • Decubitus ulceration

42. How do I treat the fever?

43. With respect ?

44. How do I treat? • Difficult question • Do I use antipyretics? • When to administer or change antibiotics?

45. How do I treat? • Do I use antipyretics? • Yes – in patients with “Neurological disorders” • Poor cardio- respiratory reserve

46. How do I treat? • When to administer or change antibiotics? • Generally in an unstable patient – choose to treat with broad spectrum antibiotics and pull back depending on cultures & clinical response

47. Summarizing

48. Recap • Enumerated causes of fever in the ICU • Useful to have a systematic approach to fever • Investigate & treat appropriately