Does atelectasis cause postoperative fever?

Postoperative fever is very common and occurs in 14-90% of surgical patients depending on how fever was defined in different studies and patient population. The incidence of infection in patients with postoperative fever is less than 10%. Fever on postoperative day 1 is most often a nonspecific response to the injury at the surgical site. Trauma leads to release pyrogenic cytokines, such as interleukins, tumor necrosis factor, and interferon-γ.

Atelectasis is defined as a state in which the lung, in whole or in part, is collapsed or without air (see the CXR below). Etymology: from Greek atelēs, incomplete, defective (telos, end) and ektasis, extension, from ekteinein to stretch out.

Right lung atelectasis with mediastinal shift. ETT ends at the level of clavicles. The optimal position is in the middle between the clavicles and the carina. This ETT needs to be advanced 2 cm. Image source: Atelectasis due to Hypoventilation and Mucus Plug. Clinical Cases and Images.

Does atelectasis cause postoperative fever?

Atelectasis does not cause fever, despite common misconception to the contrary. A study of 100 cardiac surgery patients evaluated them for 2 days after surgery with daily portable CXRs and continuous temperature measurements. During the study period, the incidence of fever progressively decreased while that of atelectasis increased, showing a negative correlation between them. Atelectasis and fever occur frequently after surgery, but their concurrence is probably coincidental rather than causal.

Incentive spirometry is used to prevent or treat atelectasis after surgery.

When evaluating postoperative fever, a helpful mnemonic is the “5 Ws”:
  • Wind (pulmonary causes: pneumonia, aspiration, and pulmonary embolism, but not atelectasis)
  • Water (urinary tract infection)
  • Wound (surgical site infection)
  • Walking limited (deep vein thrombosis or pulmonary embolism)
  • “What did we do?” (iatrogenic causes: drug fever, blood product reaction, infections related to intravenous lines)
1. Evaluating postoperative fever: A focused approach. J. Pile. Clev Clin J Med. Vol. 73, Suppl. 1, Mar 2006.
2. Postoperative fever. H. Weed, L. Baddour. UpToDate 2006, Version 14.2, Sep 15, 2005.


  1. How apropos--was just reviewing the 5 W's for Boards. (And I don't care how right you are, which you probably are, I'm still answered "atelectasis" for Step 2.)

  2. Good luck on the boards, Graham!

    They will probably change the correct answer to the one which is evidence-based (see above) eventually but it may take a few years...

  3. Great, thanks for this! I just had a nurse tell my post-operative mother that her fever was due to atlectasis. I thought it sounded bogus, now I know I was right and can be more assertive in having this evaluated and not blown off.

  4. Although i lean more that atelectasis does not cause fever, but why didn't this study follow up for the temprature variations after those orphan two days?

  5. I am a nurse and just had two post op toddlers with high temps. I was googling to help understand how atelectasis causes post op fevers. I'm glad to know they're unrelated and will use the information in my practice.