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Pediatr Pulmonol. 2013 Aug;48(8):824-9. doi: 10.1002/ppul.22671. Epub 2012 Sep 4.

Changes in gastric pressure and volume during mechanical in-exsufflation.

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Department of Nursing, The Children's Hospital of Philadelphia, Pennsylvania 19104, USA.



A mechanical insufflator-exsufflator (MI-E) is used to replicate spontaneous cough in weak or neurologically impaired patients. Its use is often withheld after abdominal surgery because of concerns for potential wound dehiscence from abdominal distension or development of excessive abdominal positive pressure. We hypothesized that gastric pressure during MI-E use would not exceed usual pressures generated during a spontaneous cough.


Thirteen subjects 0.8-23.1 years (mean 10.5 years) with neuromuscular weakness, pre-existing gastrostomy tube, and established MI-E routine were studied. A pressure transducer through the gastrostomy tube measured gastric pressure (Pgas) during MI-E treatment. Chest and abdominal volume change was assessed by respiratory inductance plethysmography. In three subjects, the same measurements were made during spontaneous cough.


The maximum Pgas was 24 cm with applied pressures of 20-40 cm. In the three subjects able to cough, the maximum Pgas achieved during the spontaneous maneuver was 25 cm, a value higher than they achieved with MI-E treatment.


MI-E resulted in less positive abdominal pressure than has been described in healthy subjects during spontaneous coughing. As such, use of an MI-E device should be considered safe to use in the post-operative period following abdominal surgery in patients with neuromuscular weakness.


MI-E; airway clearance; cough assist; neuromuscular disease; pediatric

[Indexed for MEDLINE]

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