PATHOPHYSIOLOGY

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-decreased lung compliance
-reduced lung volume
-preserved normal expiratory flow rates
-reduced FEV1
-reduced FVC
-normal FEV1/FVC
decreased lung compliance results in:
-increased work of breathing
-results in increased respiratory rate and decreased tidal volume
-respiratory gas exchange may be adequate until the progression of disease worsens

Chronic Intrinsic Pulmonary Disorders
Preoperative management
Intraoperative management

CHRONIC INTRINSIC PULMONARY DISEASE
PATHOPHYSIOLOGY
“interstitial lung disease”
-chronic inflammation of alveolar walls
-inflammation of perialveolar tissue
-progressive pulmonary fibrosis

causes of interstitial lung disease may involves:
-occupation pollutants leading to hypersensitivity pneumonitis
-environmental pollutants leading to hypersensitivity pneumonitis
-drug toxicity may lead to pulmonary fibrosis (ex. bleomycin)
-radiation pneumonitis
-autoimmune diseases
-sarcoidosis

ANESTHETIC MANAGEMENT

Preoperative management:
Inquire into presense of the following:
-dyspnea upon exertion
-nonproductive cough
-symptoms of cor pulmonale
-signs of RV failure
-fine crackles over the lung base
chest radiograph may reveal:
-initial “ground glass” appearance
-progressing to prominent reticulonodular markings
-eventually to “ honey-comb” appearance
arterial blood gas samples may reveal:
-mild hypoxemia
-normocarbia

preoperative pulmonary function test often reveal:
-reduced FEV1
-reduced FVC
-normal FEV1/FVC
-DLCO often reduced to 30 - 50%

risk of postoperative pulmonary complications may be revealed by degree of dyspnea and PFT
-degree of dyspnea should be further correlated with PFT and ABG sampling
-vital capacity < 15 ml/kg correlates with severe pulmonary impairment

Intraoperative Management
-preoxygenation is crucial due to decreased FRC
-decreased FRC subjects the patients to rapid oxygen desaturation and hypoxemia
-inspired oxygen concentration may be lowered to a Sp02 > 91% to reduce risk of 02 toxicity
-ventilation should be maintained with decreased tidal volumes and increased respiratory rate
-avoid barotraumas (ex.Ptx) with mechanical ventilation (hence dec volume and increased rate)