Chest
-
Diaphragmatic flutter is a rarely reported disorder in which the diaphragm involuntarily contracts at a rapid rate. We report a unique case in which diaphragmatic flutter was associated with inspiratory stridor and was severely disabling. A new approach to the treatment of this condition, phrenic nerve crush, provided an optimal outcome, with resolution of symptoms and the return of normal diaphragmatic function. Pathophysiology and treatment of this condition are discussed.
-
Comparative Study
Does airway pressure release ventilation alter lung function after acute lung injury?
During airway pressure release ventilation (APRV), tidal ventilation occurs between the increased lung volume established by the application of continuous positive airway pressure (CPAP) and the relaxation volume of the respiratory system. Concern has been expressed that release of CPAP may cause unstable alveoli to collapse and not reinflate when airway pressure is restored. ⋯ Intrapulmonary venous admixture, arterial oxyhemoglobin saturation, and oxygen delivery were maintained by APRV at levels induced by CPAP despite the presence of unstable alveoli. Decrease in PaO2 was caused by increase in pHa and decrease in PaCO2, not by deterioration of pulmonary function. We conclude that periodic decrease of airway pressure created by APRV does not cause significant deterioration in oxygenation or lung mechanics.
-
To examine the effects of diaphragmatic plication on respiratory mechanics during spontaneous breathing, we grouped 28 dogs into left phrenicotomy and plication (group L, n = 11), bilateral phrenicotomy and plication (group B, n = 9), and sham operations (group C, n = 8). In groups L and B, phrenicotomy caused significant (p < 0.05) decreases in tidal volume (VT), transdiaphragmatic pressure (delta Pdi), the ratio of gastric to esophageal pressure (delta Pga/delta Pes) and dynamic lung compliance (Cdyn), and significant (p < 0.05) increases in esophageal pressure (delta Pes), and the work of breathing (WOB) per liter of ventilation. ⋯ In eight left-phrenicotomized open-chest dogs, transdiaphragmatic pressure (Pdi) and fractional shortening (FS) of right hemidiaphragm by right phrenic nerve stimulation increased significantly (p < 0.05) after plication, compared with the phrenicotomy condition, suggesting more effective kinetics of the right hemidiaphragm after plication of the left hemidiaphragm. Our results showed that diaphragmatic plication for unilateral paralysis is more effective than for bilateral paralysis, indicating that an improvement in kinetics of the intact hemidiaphragm plays an important role in functional recovery.