The activity of the nervous system determines the respiratory pattern, although the degree of alveolar ventilation also depends on the mechanical properties of the chest wall and lungs. Failure to ventilate the lungs adequately may be due to defects in respiratory control or the respiratory muscles or to an increase in the work that the muscles have to perform. The selection of the best method of treatment of respiratory pump failure requires an exact knowledge of its cause. Phrenic nerve stimulation or mechanical assistance by positive and negative pressure ventilators or by a rocking bed, can be very effective. Each of these methods has a place in the long-term management of ventilatory failure. Respiratory Pump Failure and Its Treatment J M Shneerson Pacing Clin Electrophysiol 1989 May;12(5):844-6. doi: 10.1111/j.1540-8159.1989.tb01908.x.
Patients with respiratory failure usually appear distressed, quiet, depressed-looking, with altered mental status. Physical examination of patients with respiratory failure is usually remarkable for dyspnea, stridor, and tachypnea. Patients with injury to some part of the pump, however, may present with bradypnea [hidden-must measure respiratory rate for one minute with stop watch to uncover] and active exhalation [again hidden unless one gets patient to lie down while one watches for active exhalation allowing for such a slow respiratory rate], and in severe cases will have difficulty remembering or organizing obvious personal details such as knowing one’s address or being able to spell WORLD forward and backward. This is evidence of altered mental status interfering with doing anything that these patients could do previously. Altered mental status is reversible with supportive breathing support and treatments.