Respiratory Support for Neurologic Diseases
Most common neurologic indication for ICU: respiratory monitoring and support. Factors predisposing to pulmonary complications and respiratory failure: depressed consciousness; impaired airway due to depressed cough and gag reflexes; immobilization or paralysis; oropharyngeal and respiratory muscle weakness.
Table 152.1 Pulmonary Function Tests in Neuromuscular Respiratory Failure | ||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| ||||||||||||||||||||
Respiratory failure: impaired gas exchange (Pao2 <60 mm Hg or Paco2 >50 mm Hg).
Premonitory signs: restlessness, insomnia, confusion, tachycardia, tachypnea, diaphoresis, asterixis, headache.
Causes of hypoxemia: low inspired oxygen concentration, alveolar hypoventilation, ventilation-perfusion mismatch, intracardiac right-to-left shunting, impaired diffusion.
Causes of hypercapnia: increased CO2 production or inhalation, alveolar hypoventilation, ventilation-perfusion mismatching with “dead-space” ventilation.
Pulmonary function tests assess respiratory function in patients with neuromuscular respiratory failure (Table 152.1).
Neurologic Diseases with Primary Respiratory Dysfunction
Brainstem Disease
Abnormal respiratory patterns from brainstem damage (see Chapter 4), often lead to endotracheal intubation.
Diagnosis of brain death includes formal apnea testing: pre-oxygenate patient with 100% oxygen, return Pco2 to 40 mm Hg, turn off ventilator, allow Pco2 to rise above 55 mm Hg.
Related posts:
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
