Pulmonary Physiology Flashcards
OSA: ____________ secondary to reduction in ___________ tone during sleep
mechanical obstruction, pharyngeal muscle
OHS: _________________ with no mechanical, neuromuscular, or metabolic etiology
obesity/sleep-disordered breathing/daytime hypoventilation
Most significant risk factor
Obesity
______ of obese patients and
_______ of patients presenting for bariatric surgery
Increasing prevalence in _________ patients
40%, 80%, pediatric
OSA is associated with increased ____________ in hospitalized patients
morbidity/mortality
OSA results in chronic _________ leading to an inflammatory state
hypoxemia and hypercarbia
OSA inflammatory state promotes the development of:
atherosclerosis, hypertension, stroke, insulin resistance/diabetes mellitus, dyslipidemia, etc.
T/F: OSA decreases FRC
True- decreased apneic oxygen reserve, contributes to hypoxemia and hypercarbia
Hallmark of OSA
daytime somnolence due to habitual snoring and fragmented sleep
_________ provides definitive objective diagnosis and gradation of severity
Polysomnography
What is the Apnea Plus Hypopnea (AHI) Index?
number of abnormal respiratory events per hour of sleep
READ THIS:
>5 with sleep-related symptoms or >15 without sleep-related symptoms
Moderate OSA: >15
Severe OSA: >30
What does STOP stand for?
S- Snoring
T- tiredness
O-observed apnea
P- high blood pressure
What does BANG stand for?
B- Body mass index >35 kg/m2
A- Age > 50 years
N- Neck circumference > 40 cm
G- Gender, male
Lifestyle treatment for OSA
Weight loss
Medical treatment for OSA
CPAP, airway devices, medications (modafinil, methylxanthines, tricyclic antidepressants)
Surgical treatment for OSA
adenotonsillectomy, uvulopalatopharyngoplasty, hypoglossal nerve stimulator
Induction considerations for OSA
- Anticipate difficult mask ventilation/laryngoscopy
- decreased FRC= decreased apneic oxygen time
- Elevate head and shoulders (ramping)
- Have airway adjuncts (LMA/videolaryngoscope) available
Preoperative considerations for OSA:
- Bring CPAP on day of surgery
- Airway examination- anticipate difficult mask ventilation/laryngoscopy
- Mallampati and neck circumference
- Consider regional anesthesia or multimodal analgesia (minimize need for meds that produce sedation)
- Minimize/avoid sedatives (patient with OSA may be more sensitive to sedative effects)
Emergence considerations for OSA
- Consider awake extubation
Postoperative considerations for OSA
- Monitor ventilation and oxygenation
- Consider CPAP in PACU
- Consider prolonged monitoring (6 -24 hours)
What is preventable and treatable disease state characterized by airflow limitation that is not fully reversible. The airflow limitation is usually progressive and is associated with an abnormal inflammatory response of the lungs to noxious particles or gases
COPD
Chronic bronchitis: ____________ of expiratory airflow by excess ____________.
Obstruction, mucous secretion
Chronic bronchitis occurs most days for at least __________ per year for at least ______ successive years
3 months, 2
Emphysema is _________ abnormal enlargement of air spaces distal to the terminal bronchioles accompanied by irreversible destruction of _________ ________.
permanent, alveolar walls
______lobular: predominantly affects respiratory bronchioles in upper lung lobes
Centrilobular
______lobular: widespread destruction of acini
Panlobular
What is the most significant risk factor for COPD?
Cigarette smoking (Others: Environmental pollutants, genetics)
COPD is ______ leading cause of death; ~___% of American adults
3rd, 5
Death may be secondary to respiratory failure or related comorbidities (e.g., heart disease, lung cancer)
COPD pathophysiology:
* _________ in intrinsic size of bronchial lumina
* _________ in collapsibility of bronchial walls
* __________ in elastic recoil of the lungs
Decrease, increase, decrease
COPD pathophysiology:
- Increased size of acini/alveoli causes compression of adjacent small airways, thereby increasing resistance to airflow
- Consolidation of alveoli leads to loss of alveolar surface area and impaired gas diffusion
- Mismatched ventilation/perfusion due to heterogeneity of the disease
- Loss of alveolar walls decreases the number of pulmonary capillaries, which increases right ventricular workload
Hallmark for COPD
chronic productive cough and progressive exercise limitations
Clinical manifestations for COPD
dyspnea, wheezing
Pulmonary Function Testing (i.e., GOLD Classification)
FEV1 >80%(or equal to) = ________
FEV1 50%-79% = ________
FEV1 30%-49% = ________
FEV1 <30% = ________
mild, moderate, severe, very severe
ABG of someone with COPD
PaO2 <60 mm Hg
PaCO2 >45 mm Hg
Lifestyle treatment for COPD
smoking cessation, influenza vaccination
Medical treatment for COPD
bronchodilation: B2-agonists, anticholinergics, corticosteroids
Surgical treatment for COPD
bullectomy, lung volume reduction surgery (LVRS), lung transplantation
Preoperative considerations for COPD
- Assess symptoms, severity of airflow limitation, history of exacerbations, and comorbidities
- Cough, dyspnea, chest discomfort, and fatigue are signs/symptoms of acute exacerbation
- Consider regional anesthesia
Maintainence for COPD
- Volatile anesthetics promote bronchodilation
- Consider humidification of inspired gas
- Ventilation
- Maintain adequate oxygenation
- Eliminate CO2
- Avoid barotrauma (high PIP)
- Avoid alveolar injury secondary to atelectasis
- Avoid volutrauma secondary to high Vt or auto-PEEP
Postoperative Considerations
- Consider postoperative mechanical ventilation
- Incentive spirometry
Chronic inflammatory disorder of the airways in which many cells and cellular elements play a role… In susceptible individuals, this inflammation causes recurrent episodes of coughing (particularly at night or in the early morning), wheezing, breathlessness, and chest tightness. These episodes are usually associated with widespread but variable airflow obstruction that is often reversible either spontaneously or with treatment.”
Asthma
What are the four pathophysiological alterations of asthma?
- Bronchoconstriction – bronchial smooth muscle contraction that narrows airways in response to variety of stimuli
- Airway hyperresponsiveness – exaggerated bronchoconstrictor response to stimuli
- Mucous secretion – hypersecretion of mucin
- Airway edema
Allergic asthma is triggered by
presentation of antigens
(Asthma) Antigens provoke
T-lymphocytes to generate an IgE-mediated immune response
(Asthma) Proinflammatory cascade results in
proliferation of eosinophils, neutrophils, mast cells, and macrophages
(Asthma) results in
- increased smooth airway muscle tone (bronchoconstriction)
- increased mucous secretion
- submucosal edema
- pulmonary vasoconstriction and increased vascular permeability
Type of asthma that may be related to high minute ventilation or low temperature/humidity of inspired gas
Exercise
Type of asthma that causes inhaled irritants to stimulate vagal nerve endings in the airway epithelium
Occupational
(Asthma) Secondary to acute inflammation due to viral/bacterial/mycoplasmal infection
Infection (I know this is redundant lol)
Type of asthma that results in inhibition of cyclooxygenase results in greater production of leukotrienes
Aspirin
Clinical manifestations of asthma
Recurrent wheezing, dyspnea, cough, tachypnea, chest tightness, fatigue
Asthma attacks are short-lived, lasting ______ long symptom-free periods between attacks
minutes to hours
Airflow obstruction that is refractory to bronchodilator therapy is known as
Status asthmaticus
During exacerbations, airflow obstruction is indicated by
decreased FEF25-75%
Asthma preoperative considerations
- Review symptom control prior to surgery (pulmonary function, medication use)
- Consider canceling the procedure if optimization is necessary
- Consider regional anesthesia
Asthma induction considerations:
- Avoid endotracheal intubation if possible; consider supraglottic airway if appropriate
- Ketamine> Propofol > Etomidate/Barbiturates
Asthma maintenance considerations
- Consider use of sevoflurane, least irritating volatile anesthetic
- Avoid atracurium, mivacurium, morphine, B-antagonists, Hemabate, NSAIDs
Asthma emergence considerations
- Consider deep extubation
- Consider use of Sugammadex; anticholinesterase reversal agents have risk of bronchospasm
- Verify adequate reversal of neuromuscular blockade
Intraoperative Bronchospasm: (Way to remember- a1b2eca)
- Administer additional anesthetic agents
- Increase FiO2 to 1.0 (100%)
- Administer short acting B2-agonist (albuterol)
- Consider administering epinephrine 10 mcg/kg
- Administer a corticosteroid (hydrocortisone 2-4 mg/kg)
- Consider administering aminophylline