Evaluation of assisted cough with air stacking in patients with tetraplegia

INTRODUCTION : A significant number of patients with tetraplegia require prolonged mechanical ventilation and use of tracheostomy. For an effective weaning, a thorough analysis of the ability to cough is required. The cough effectiveness is related to the peak cough flow (PCF). Lower PCF values has been described as ineffective and are associated with a greater risk of pulmonary infections. There are techniques to assist cough by increasing the inspiratory volume and the expiratory flow. The manual Air Stacking (AS) technique has been proven as effective in neuromuscular disease. OBJECTIVE: to assess cough efficacy using air stacking and manual compression in patients with tetraplegia with A ASIA Score. METHODS: 11 hospitalized patients with tetraplegia (A ASIA Score) were selected. Measures: PCF during four different interventions: spontaneous maximal expiratory effort (MEE); MEE while receiving abdominal compression (MEE+Abd); MEE after air stacking with a manual resuscitation bag (MEE+AS); and MEE with air stacking and compression (MEE+Add+AS). RESULTS: median age 33 years (16-56 years). The PCF during the different interventions was: MEE 156±53 L/min; MEE+Abd 235±113 L/min; MEE+AS 225±61 L/min, and MEE+Abd+AS 303±96 L/min. We observed PCF increase while applying combination techniques but only significant differences existed between PCF with MEE and MEE+Abd+AS (p=0.0001). CONCLUSION: According to our results, patients with spinal cord injury presented an ineffective cough constituting a risk factor for developing respiratory symptoms. The application of combined techniques (MEE+Abd+AS) can reach near normal PCF values. Those are low cost, simple and easy applied intervention.