Maximum inspiratory pressure

The most common causes of failure to wean include chronic obstructive pulmonary disease (COPD) exacerbations, neuromuscular diseases, h) oxic respiratory failure, post surgical complications (2), and heart failure. Weaning from the tracheostomy must consider the balance of respiratory muscle function and work of breathing. The work of breathing is determined by ventilatory demand, compliance of the lungs and chest wall, airway resistance, and intrinsic positive end-expiratory pressure (PEEPi). Adequacy of ventilatory drive and neuromechanical output can be assessed from the respiratory rate, airway occlusion pressure at 100 milliseconds (Po.i), maximum inspiratory pressure (MIP), and maximum voluntary ventilation (MW). 

PIP Peak inspiratory pressure the maximum level of pressure achieved by the ventilator during inspiration. 

Figure 7 Peak inspiratory flow rate versus device resistance for patient-driven dry-powder inhalers illustrating comfortable and maximum effort curves for healthy volunteers. (From Ref. 34.) The United States Pharmacopiea specifies that DPIs should be tested at a device pressure drop of 4 kPa.

Figure 6 Relationship between muscle strength and mixed venous partial pressure of CO2 (PVCO2) in patients with respiratory muscle weakness. Respiratory muscle strength is the arithmetic sum of maximum static inspiratory and expiratory mouth pressures (P iax = + TEmax)- The open circles...

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