CURRENT Essentials of Critical Care.pdf

Chapter 8 Respiratory Failure 107■■■Respiratory Failure from Thoracic Cage DisordersEssentials of Diagnosis• Structural or functional abnormality of chest wall or diaphragm• PaCO 2 50 mm Hg, usually with hypoxemia• Some disorders limit chest expansion (restriction), such askyphoscoliosis or ankylosing spondylitis, pleural effusions, restrictivepleuritis• Truncal obesity, pregnancy, ascites, severe abdominalorganomegaly, recent abdominal surgery limit diaphragmaticexcursion• Severe chronic thoracic cage disorders may lead to pulmonaryhypertension and cor pulmonale• Severely obese patients have a high likelihood of obstructivesleep apnea (OSA) and obesity hypoventilation syndrome(OHS)Differential Diagnosis• Primary lung diseases (COPD, asthma, interstitial lung disease)• Neuromuscular disease with respiratory muscle weaknessTreatment• Treat underlying disease• Oxygen for hypoxemia due to atelectasis or pneumonia• Endotracheal intubation and mechanical ventilation for hypercapnia;may try noninvasive positive pressure ventilation if mild,reversible cause■ PearlPatients with weakness have disproportionate atelectasis, inability toclear secretions and pneumonia (frequent suctioning and mobilizationof secretions), and pulmonary thromboembolic disease compared toother chest wall disorders.ReferenceGoldstein RS: Hypoventilation: neuromuscular and chest wall disorders. ClinChest Med 1992;13:507. [PMID: 1521416]