What is the function of volume recruitment/deep lung inflation technique for the respiratory management of Duchenne muscular dystrophy (DMD)?

Updated: Aug 17, 2020
  • Author: Twee T Do, MD; Chief Editor: Jeffrey D Thomson, MD  more...
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Volume recruitment/deep lung inflation technique (by self-inflating manual ventilation bag or mechanical insufflation-exsufflation) is used when the forced vital capacity (FVC) reaches <40% predicted.

Step 2: Manual and mechanically assisted cough techniques

These techniques are necessary in any of the following situations:

  • Respiratory infection is present and baseline peak cough flow <270 L/min
  • Baseline peak cough flow <160 L/min or maximum expiratory pressure <40 cm water
  • Baseline FVC <40% predicted or <1.25 L in older teenager/adult

Step 3: Nocturnal ventilation

Nocturnal ventilation is indicated in patients who have any of the following:

  • Signs or symptoms of hypoventilation (patients with FVC <30% predicted are at especially high risk)
  • Baseline oxygen saturation by pulse oximetry (SpO 2) <95% and/or blood or end-tidal CO 2 >45 mm Hg while awake
  • Apnea–hypopnea index >10 per hour on polysomnography or four or more episodes of SpO 2 <92% or drops in SpO 2 of at least 4% per hour of sleep

Use of lung volume recruitment and assisted cough techniques should always precede initiation of noninvasive ventilation.

Step 4: Daytime ventilation

In patients already using nocturnally assisted ventilation, daytime ventilation is indicated for any of the following:

  • Self-extension of nocturnal ventilation into waking hours
  • Abnormal deglutition due to dyspnea, which is relieved by ventilatory assistance
  • Inability to speak a full sentence without breathlessness
  • Symptoms of hypoventilation with baseline SpO 2 <95% and/or blood or end-tidal CO 2 >45 mm Hg while awake

Continuous noninvasive assisted ventilation (with mechanically assisted cough) can facilitate endotracheal extubation for patients who were intubated during acute illness or during anesthesia, followed by weaning to nocturnal noninvasive assisted ventilation, if applicable.

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