Incentive Spirometry

Incentive spirometry is a lung expansion technique that uses a mechanical device to encourage patients to take slow, deep, sustained maximal inspirations (SMI) to prevent or reverse atelectasis, particularly in the post-operative period. Understanding the physiology of normal breathing, the mechanics of atelectasis, and the therapeutic principles behind incentive spirometry is essential for the practical nurse to educate patients effectively and monitor outcomes. Normal quiet breathing (tidal breathing) uses only a fraction of the lung's total capacity. Tidal volume, the amount of air moved in and out with each normal breath, is approximately 500 mL in an adult. However, the total lung capacity is approximately 6000 mL. During tidal breathing, the bases and dependent portions of the lungs receive less ventilation, and some alveoli may not be fully expanded. In healthy individuals, periodic spontaneous deep breaths (sighs) occur 6-10 times per hour, inflating these under-ventilated alveoli and preventing collapse. These sighs generate transpulmonary pressures sufficient to open collapsed alveoli and redistribute surfactant. Atelectasis is the partial or complete collapse of lung tissue resulting from alveolar deflation. Post-operative atelectasis is the...