Paradoxical abdominal breathing

Specialty: Respiratory.

• seesaw breathing
• thoracoabdominal dissociation
• abdominal respiratory asynchrony

Why it occurs

• Extreme respiratory muscle fatigue due to severe airway obstruction or acute respiratory distress (failure of the diaphragm being passively sucked upward by negative intrathoracic pressure during inspiration)
• Bilateral diaphragmatic paralysis (complete loss of active contraction of the diaphragm due to phrenic nerve injury or motor neuron disease)
• Rib volet or unstable chest (multiple consecutive rib fractures in two or more points that generate a mobile costal segment that moves in the opposite direction to the rest of the thorax)
• Amyotrophic lateral sclerosis (ALS) or advanced muscular dystrophy (progressive muscle weakness with selective impairment of the respiratory pump)
• Acute demyelinating polyneuropathy (Guillain-Barré Syndrome) with involvement of the phrenic nerve

Initial workup

Urgent arterial blood gases; Chest x-ray (to evaluate rib fractures, atelectasis or diaphragmatic elevation); Dynamic diaphragmatic ultrasound (to measure diaphragmatic thickness and percentage of inspiratory excursion); Electromyography of the diaphragm and phrenic nerve conduction velocity; Respiratory function tests (PIM, PEM and forced vital capacity in recumbency and standing).

Standard management

• There are no specific drugs to reverse paradoxical mechanical breathing; immediate non-invasive ventilatory support (BiPAP) or invasive is required
• IPratropium bromide — nebulized, 0.5 mg every 6 hours if there is an underlying severe bronchospasm component
• Methylprednisolone (40-80 mg intravenously every 12 hours if there is an acute inflammatory component of the airway).