Cough Augmentation Techniques in the Critically Ill: A Canadian National Survey

Critically ill mechanically ventilated patients experience impaired airway clearance due to ineffective cough and impaired secretion mobilization. Cough augmentation techniques, including mechanical insufflation-exsufflation (MI-E), manually assisted cough, and lung volume recruitment, improve cough efficiency. Our objective was to describe use, indications, contraindications, interfaces, settings, complications, and barriers to use across Canada.

An e-mail survey was sent to nominated local survey champions in eligible Canadian units (ICUs, weaning centers, and intermediate care units) with 4 telephone/e-mail reminders.

The survey response rate was 157 of 238 (66%); 78 of 157 units (50%) used cough augmentation, with 50 (64%) using MI-E, 53 (68%) using manually assisted cough, and 62 (79%) using lung volume recruitment. Secretion clearance was the most common indication (MI-E, 92%; manually assisted cough, 88%; lung volume recruitment, 76%), although the most common units (44%) used it <50% of the time. Use during weaning from invasive (MI-E, 21%; manually assisted cough, 39%; lung volume recruitment, 3%) and noninvasive ventilation (MI-E, 21%; manually assisted cough, 33%; lung volume recruitment, 21%) was infrequent. The most common diagnoses were neuromuscular disease (97%) and spinal cord injury (83%). Pneumothorax was the most frequently identified absolute contraindication for MI-E (93%) and lung volume recruitment (83%); rib fracture was most frequently identified for manually assisted cough (69%). MI-E mean inspiratory pressure was 31 cm H2O, and expiratory pressure was -32 cm H2O. Mucus plugging requiring tracheostomy inner change was the most frequent complication for MI-E (23%), chest pain for manually assisted cough (36%), and hypotension for lung volume recruitment (17%). The most commonly cited barriers were lack of expertise (70%), knowledge (65%), and resources (52%).

We found moderate adoption of cough augmentation techniques, particularly for secretion management. Lack of expertise and knowledge are potentially modifiable barriers addressed with educational interventions.