When is the most critical moment for an asthmatic during anesthesia?
During airway manipulation. Make sure you have an adequate anesthetic depth before proceeding.
What are the 4 components that lead to poor gas exchange and an increase in V/Q mismatching with COPD?
- Intrapulmonary shunt
- Increase in dead space ventilation
- Capillary destruction
- Alveolar destruction and formation of blebs
What is seen on a flow-volume loop in someone with a variable intrathroacic lesion?
Normal inspiration, blunted expiration
Describe a restrictive flow-volume loop.
Rightward shift, similar shape to normal curve, lower than normal flow rates.
What are some preoperative considerations for COPD patients?
- Recent changes in symptoms (want them at baseline)
- Chest X-ray, +/- PFT’s
- Baseline ABG
- Cardiac evaluaion
- Infection control
- Taking bronchodilators/steroids/anticholinergics
- How long has it been since they’ve stopped smoking
T or F: Patients with COPD need a larger I:E ratio during controlled ventilation?
False:
Because it takes longer for these patients to exhale, they need a smaller I:E ratio. They need to spend more time during expiration to allow for adequate gas removal from alveoli and small airways.
Describe the typcial sequence of events during an untreated asthma attack.
- Bronchial smooth muscle hyperactivity
- Airflow limitations (primarily during exhalation)
- Inflammatory response (increase swelling and mucous)
- Continued or worsening bronchospasm
- Alveolar fluid extravasation (swelling)
What are 3 risk factors predisposing a patient to post-op pulmonary complications?
- Operation site (thoracic and upper abdominal)
- Duration of procedure
- Pre-op pulmonary dysfunction (dyspnea, smoking history, age, obesity)
What are important things to know about an asthmatic patient preoperatively?
- Baseline peak flows
- Severity of asthma (# of attacks, resolution of attacks)
- Clinical history (steroid use, intubation history, current wheezing status)
- Exacerbating factors
- Do you need to give a bronchodilator/glucocorticoids/supplemental 02 preoperatively to optimize patient status?
- Do you need to sedate to decrease anxiety?
- Do you need to give a stress dose of steroids?
What happens to the size of alveoli in someone with COPD?
They get larger.
Alveoli merge to form giant blebs. There is also a destruction in the capillary beds perfusing the alveoli.
T or F: It is beneficial for a patient to stop smoking any time before their surgery?
False:
You want them to quit 6-8 weeks before surgery. Any less than that you can have a hyperresponse and increase secretions.
Name 4 possible post-operative pulmonary complications.
- Atelectasis
- Pneumonia
- Pulmonary embolism
- Respiratory failure
What type of pulmonary disease is characterized by normal expiratory flows but difficulty during inspiration?
Restrictive lung disease
What is the most common pulmonary disorder?
COPD
T or F: There is a reversible component to the obstructive nature in patients with mild to moderate COPD?
True:
These patients often benefit from bronchodilators and secretion drying agents.
What are the three comon characteristics of asthma?
- Hyperreactive airways
- Bronchoconstriction
- Inflammatory response
T or F: In COPD, epithelial cells are destroyed and replaced by fibroblasts creating scar tissue in the lung parenchyma?
True
What is the benefit of using epinephrine during an asthma attack?
It acts as a bronchodilator and blunts the inflammatory response.
Define chronic bronchitis.
Patient must have a chronic productive cough most days lasting at lease 3 months for 2 years.
T or F: All wheezing is caused by asthma?
False:
You could have mainstemmed during intubation, have light anesthesia, an allergic reaction, obstructed ETT, increased secretions, pulmonary edema, pulmonary embolism, pneumothorax
List 4 preoperative interventions we can do to optimize conditions in patients with COPD.
- Correct hypoxemia
- Correct bronchospasm
- Mobilize/dry secretions
- Control infections
Name 5 effects of chronic hypoxemia.
- Erythrocytosis
- Pulmonary HTN –> R heart failure
- CO2 retention resulting from an increased work of breathing
- Respiratory acidosis, increase bicarbonate production
- Blunted hypercapnic drive to breathe
What is seen on a flow-volume loop in someone with a variable extrathoracic lesion?
Normal expiration, blunted inspiration
What are common treatments for asthma?
- Bronchodilators (B2 agonists)
- Steroids (anti-inflammatory)
- Anticholinergics (decrease secretions)
- Methylxanthines (bronchodilator but NOT B2 agonist, ex. caffeine)
