Normal breathing

• Yawning is part of normal breathing.yawn image by Tatyana Gladskih from Fotolia.com
  
  Air enters the lungs during inspiration and passes through bronchial tubes. These become increasing small, ending in tiny grape-like clusters called alveoli.
  
  It is through the thin walls of these tiny alveolar sacs, smaller than a grain of salt, that carbon dioxide passes from the blood and oxygen passes into the blood (gaseous exchange). Normal breathing includes occasional sighing, yawning or taking very deep breaths, which expands the lungs fully, forcing air into the alveoli.
  
  

Reduced Lung Function

• Surgery weakens muscles.laparoscopic surgery image by Grzegorz Kwolek from Fotolia.com
  
  Muscles affected by surgery are weak and less effective until fully healed. If these are in the chest or abdomen, post-operative patients may be reluctant to take deep breaths because of discomfort or pain. This may cause mucus to collect in the lungs or even partial collapse of the lung (atelactesis) giving the potential for chest infection.
  
  

How It Works

• The Respiratory Care Journal states that the incentive spirometer is intended to enable people to mimic sighing and yawning and to breathe evenly and deeply.
  
  Visual indicators on the device show when maximum inhalation is reached. Users breathe in until the indicator has reached its maximum point, then hold the breath for at least five seconds, breathing out only when the indicator returns to zero. The exercise is repeated at least four or five times per hour.
  
  The visual indicators enable patients to assess their own breathing technique.
  
  

Fever

• Fever is the body's natural response to infection.Help image by Vojsek from Fotolia.com
  
  Fever is part of the body's natural response to infection.
  
  The viruses and bacteria which cause infection survive at 98.6 degrees Fahrenheit (37 degrees Celsius), the average body temperature. The rise in temperature creates an uncomfortable environment for the infective agent and activates the body's immune system to fight off the invaders.
  
  

Theories/Speculation

• Research on I.S. is conflicting.
  
  A literature review at University of Western Ontario concluded that current evidence does not indicate that spirometry decreases postoperative lung complaints following thoracic or abdominal surgery. However, research at --rebro University Hospital, Sweden,concluded that deep breathing exercises, with or without spirometry, does reduce such complications.
  
  

Expert Insight

• The American Physical Therapy Association concluded that using I.S. was of benefit to approximately 12 percent of patients in their study. They identified a problem with compliance; left to use the spirometer alone, patients tend to miss out on sessions and the device is frequently left beyond their reach by staff.
  
  Agostini and colleagues stated that "regular physiotherapy remains the most effective mechanism to augment (the) patient's recovery and avoid post-operative complications."
  
  

Conclusion

• Current research in the pre- and post-operative use of I.S. is inconclusive and there is no evidence that it has any direct effect upon fever. Although anecdotal reports from Ultimate Nurse forum suggests that it may do so, the debate continues.
  
  Pulmonary stasis however is a known cause of infection and fever and the correct use of I.S. encourages lung inflation, thereby potentially avoiding stasis and infection.
  
  It is possible that I.S. reduces the potential for fever by encouraging deep breathing.