CHRONIC OBSTRUCTIVE PULMONARY DISEASE
CHRONIC OBSTRUCTIVE PULMONARY DISEASE
-most common respiratory disorder within the anesthetic practice
-increased prevelance with age
COPD prevelance may increase with:
-increasing age
-cigarette smoking
-male predominace
Emphysema
Pathophysiology
Treatment
Preoperative management
Intraoperative management
Emergence/postoperative management
Chronic Bronchitis
Pathophysiology
Treatment
Preoperative management
Intraoperative management
Emergence postoperative management
-irreversible enlargement of airways distal to the terminal bronchioles
-destruction occurs within the alveoli septa
-destruction of alveoli septa also include damage to the pulmonary capillaries
-destruction of the pulmonary capillaries decreases the carbon monoxide diffusion capacity
-loss of elastic recoil creates premature collapse of airways during exhalation
-loss of elastic recoil is due to lack of supporting radial traction of the small airways
-generally increased: RV, FRC, TLC
-bullae: large cystic areas within some portions of the lung
-characteristic feature is dead space
-Pa02 is usually normal or slightly decreased
-PaC02 is usually normal
TREATMENT
-primarily supportive
-important intervention is smoking cessation
-long term bronchodilator therapy should be started for patients who have a reversible element to airway obstruction
-inhaled beta2 agonist, glucocorticoids, ipratropium are very beneficial in treatment
-antibiotics are often useful
-oxygen supplementation cautiously given to treat hypoxemia
*low flow oxygen therapy (1-2 L/min) for chronic hypoxic patients with Pa02<55mmHg
ANESTHETIC MANGEMENT
Inquire into any recent changes in the following:
-dyspnea
-sputum production
-wheezing
dyspnea can often be ascertained by FEV1 measurements:
-FEV1 < 50% predicted = 1.2 -1.5 L often correlated with dyspnea on exertion
-FEV1 < 25% predicted approx: 1 L often correlated with dyspnea with minimal activity
carefully evaluate the following preoperatively:
-pulmonary function tests
-chest xrays: take notice of presence/absense of bullous changes
-arterial blood gas
Factors which may help to reduce postoperative pulmonary complications include:
-correcting hypoxemia (ex. oxygen supplementation cautiously)
-alleviating bronchospasm (ex. bronchodilators)
-reducing and clearing pulmonary secretions (ex. smoking cessation, chest physiotherapy, and antibiotics)
-treating any underlying pulmonary infections (ex. antibiotics)
Patients with great risk of postoperative pulmonary complications involve :
-preoperative predicted PFTs < 50%
-therefore may postoperative mechanical ventilation
-regional anesthesia may be more beneficial in comparison to general anesthesia in COPD patients
regional anesthesia may also involve negative attributes such as:
-decreased lung volumes
-accessory respiratory muscle restriction due to high spinal
-ineffective cough due to inhibited accessory muscle use and decreased lung volumes (ex. VC)
-retention of secretions due to ineffective cough
-resultant hypoxemia may occur
general anesthesia in patients with COPD should incorporate:
-careful preoxygenation: fill FRC with 100% O2 to prevent rapid oxygen desaturation (common in COPD)
-controlled ventilation with decreased tidal volumes and increased respiratory rate ( avoid air-trapping)
-humidified gas to prevent bronchospasm and for prolonged cases x > 2hrs
-avoid N20 in patients with bullae and preexisting pulmonary hypertension
-monitor fequent ABG samples in prolonged cases, extensive abdominal cases, and all thoracic cases
intraoperative ABG:
-used to guide venilation settings
-as dead space increases (with general anesthesia) less accurate the ETCO2 becomes to monitor PaC02
-therefore ABG PaC02 becomes more essential in monitoring ventilation status
-ventilation should be focused more on normalizing the pH opposed to correcting and normalizing PaC02
-normalizing PaC02 in preoperative C02 retainers may lead to alkalosis and invite electrolyes imbalances
Emergence/Postoperative Management:
Timing of extubation should consider two opposing potential dreaded complications:
-risk of bronchospasm due to waiting longer to extubate (ex. fully awake extubation)
-risk of pulmonary insufficiency due to earlier extubation (ex. deep extubation)
-evidence supports the earlier extubation in the operating room may be beneficial if criteria are met
Patients who most likely require postoperative mechanical ventilation include:
-preoperative predicted FEV1 <50%
-upper abdominal incision
-thoracic incision
-prolonged duration of anesthesia
-productive cough on most days of three consecutive months for at least two consecutive years
factors which may be responsible for chronic bronchitis:
-cigarette smoking
-air pollutants
-exposure to dust
-recurrent pulmonary infections
-familial factors
airway obstruction may occur to due:
-hypertrophied bronchial mucosal glands leading to increased secretions
-inflammation leading to mucous edema
-increased bronchial secretions, inflammation, and edema lead to airway obstruction
bronchospasm may be associated with:
-recurrent pulmonary infections
-ex. bacterial and viral infections with increased secretions leads to hyperactive airway
hypoxemia may occur due to:
-increased bronchial secretions with mucous plugging
-increased residual volume amidst a normal total lung capacity
-results in increased intrapulmonary right to left shunt
-intrapulmonary shunting ultimately causes hypoxemia
physiological changes that occur in response to chronic hypoxemia include:
-erythrocytosis
-pulmonary hypertension
-cor pulmonale (right ventricular failure)
“chronic blue bloater syndrome”
TREATMENT
-primarily supportive
-important intervention is smoking cessation
-long term bronchodilator therapy should be started for patients who have a reversible element to airway obstruction
-inhaled beta2 agonist, glucocorticoids, ipratropium are very beneficial in treatment
-antibiotics are often useful
-oxygen supplementation cautiously given to treat hypoxemia
*low flow oxygen therapy (1-2 L/min) for chronic hypoxic patients with Pa02<55mmHg
ANESTHETIC MANGEMENT
Inquire into any recent changes in the following:
-dyspnea
-sputum production
-wheezing
dyspnea can often be ascertained by FEV1 measurements:
-FEV1 < 50% predicted = 1.2 -1.5 L often correlated with dyspnea on exertion
-FEV1 < 25% predicted approx: 1 L often correlated with dyspnea with minimal activity
carefully evaluate the following preoperatively:
-pulmonary function tests
-chest xrays: take notice of presence/absense of bullous changes
-arterial blood gas
Factors which may help to reduce postoperative pulmonary complications include:
-correcting hypoxemia (ex. oxygen supplementation cautiously)
-alleviating bronchospasm (ex. bronchodilators)
-reducing and clearing pulmonary secretions (ex. smoking cessation, chest physiotherapy, and antibiotics)
-treating any underlying pulmonary infections (ex. antibiotics)
Patients with great risk of postoperative pulmonary complications involve :
-preoperative predicted PFTs < 50%
-therefore may postoperative mechanical ventilation
-regional anesthesia may be more beneficial in comparison to general anesthesia in COPD patients
regional anesthesia may also involve negative attributes such as:
-decreased lung volumes
-accessory respiratory muscle restriction due to high spinal
-ineffective cough due to inhibited accessory muscle use and decreased lung volumes (ex. VC)
-retention of secretions due to ineffective cough
-resultant hypoxemia may occur
general anesthesia in patients with COPD should incorporate:
-careful preoxygenation: fill FRC with 100% O2 to prevent rapid oxygen desaturation (common in COPD)
-controlled ventilation with decreased tidal volumes and increased respiratory rate ( avoid air-trapping)
-humidified gas to prevent bronchospasm and for prolonged cases x > 2hrs
-avoid N20 in patients with bullae and preexisting pulmonary hypertension
-monitor fequent ABG samples in prolonged cases, extensive abdominal cases, and all thoracic cases
intraoperative ABG:
-used to guide venilation settings
-as dead space increases (with general anesthesia) less accurate the ETCO2 becomes to monitor PaC02
-therefore ABG PaC02 becomes more essential in monitoring ventilation status
-ventilation should be focused more on normalizing the pH opposed to correcting and normalizing PaC02
-normalizing PaC02 in preoperative C02 retainers may lead to alkalosis and invite electrolyes imbalances
Emergence/Postoperative Management:
Timing of extubation should consider two opposing potential dreaded complications:
-risk of bronchospasm due to waiting longer to extubate (ex. fully awake extubation)
-risk of pulmonary insufficiency due to earlier extubation (ex. deep extubation)
-evidence supports the earlier extubation in the operating room may be beneficial if criteria are met
Patients who most likely require postoperative mechanical ventilation include:
-preoperative predicted FEV1 <50%
-upper abdominal incision
-thoracic incision
-prolonged duration of anesthesia
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