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Inspiratory muscle training before cardiothoracic or upper abdominal surgery reduces lung complications from surgery

Mans CM, Reeve JC, Elkins MR. Postoperative outcomes following preoperative inspiratory muscle training in patients undergoing cardiothoracic or upper abdominal surgery: a systematic review and meta analysis. Clin Rehabil. 2015;29:426-8.

Review question

In people who have cardiothoracic (relating to the heart or chest) or upper abdominal surgery, does inspiratory muscle training before surgery reduce lung complications from surgery and length of hospital stay?


People who have cardiothoracic or upper abdominal surgery can develop complications such as pneumonia or collapsed lungs after surgery. These complications may lead to further harm and/or longer hospital stays.

Weakness of respiratory muscles may contribute to lung complications after surgery. Therefore, strengthening of inspiratory muscles—the muscles used to breathe in—through training before surgery may help reduce the risk of lung complications after surgery.

How the review was done

The researchers did a systematic review based on studies available up to December 2013.

They found 8 randomized controlled trials with 295 people (average age 35 to 71 years, 53% were men).

The key features of the studies were:

  • people had heart, chest, or upper abdominal surgery;
  • all studies used a threshold-loading device for training;
  • training ranged from 1 to 3 sessions per day for 6 or 7 days per week for at least 2 weeks; and
  • training was compared with usual care, no training, or breathing through a tube with little or no resistance.

What the researchers found

The trials had quality scores ranging from of 4/10 to 7/10.

Compared with usual care, no training, or breathing through a tube with little or no resistance, inspiratory muscle training

  • reduced lung complications after surgery; but
  • did not affect length of hospital stay or risk of death.


In people who have cardiothoracic or upper abdominal surgery, inspiratory muscle training before surgery reduces lung complications from surgery but does not reduce length of hospital stay.

Inspiratory muscle training before cardiothoracic or upper-abdominal surgery

Outcomes after surgery

Number of trials (and people)

Rate of events with training

Rate of events with no training

Effects of training

Lung complications

7 trials (249 people)



About 9 fewer people out of 100 had lung complications

Length of stay in hospital

4 trials (115 people)

Not applicable

Not applicable

No difference in the length of hospital stay


2 trials (50 people)



No difference in deaths*

*Although the rates for the 2 groups look different, the differences were not statistically significant—this means that the differences could simply be due to chance rather than due to the different treatments.


Randomized controlled trials
Studies where people are assigned to one of the treatments purely by chance.
Systematic review
A comprehensive evaluation of the available research evidence on a particular topic.

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