obstructive pulmonary dz Flashcards
Obstructive Sleep Apnea is
Recurrent upper airway collapse duringsleepleading to reduced or complete cessation of airflow, despite ongoing breathing efforts
Polysomnography recording assesses
Apnea
Hypopnea
Respiratory effort–related arousals
all are a form of obstructive apea that can be dx on a PSG.
Most common type of sleep dysfunction
Obstructive Sleep Apnea
Apnea is ……
90% or more reduction in the amplitude of airflow signal as measured by an oral/nasal thermal sensor
Classifications of apnea
Obstructive apnea event- breathing effort during apnea
Central apnea event
Mixed apnea event
Obstructive apnea event
breathing effort during apnea
Central apnea event
no breathing effort happening
Mixed apnea event
apnea starts at central and ends as obstructive
Time of apnea to be dx
Duration of 10 seconds or more
Hypopnea recommended def
A drop of 30% or more in the amplitude of the nasal pressure sensor that lasts for 90% or more of the event
Associated with a 4% or more drop in Spo2
Airflow as measured by nasal pressure sensor and Spo2
Hypopnea Alternative definition
A drop of 50% or more in the amplitude of airflow as measured by nasal pressure sensor that lasts 90% or more of the event
Associated with either a 3% or more drop in Spo2or EEG arousal
EEG arousal
abrubt shift in EEG lasting more than 3 seconds preceded by 10 seconds of normal waves
Apnea-hypopnea index (AHI)
Number of apnea and hypopnea events per hour of sleep
Medicaid accepts what definition
Recommended definition
hypopnea time diagnosis
Duration of 10 seconds or more
Respiratory Effort–related Arousals
A limitation in the airflow followed by an arousal on the EEG channel
Flattening of the airflow in a way that does not meet the criteria for apnea or hypopnea
Increased respiratory effort
Apnea-hypopnea index (AHI) diagnosis of OSA
AHI of ≥ 15 per hour of sleep
AHI > 5 plus …….
AHI of ≥ 5 plus clinical signs and symptoms present or associated medical and psychiatric disorders correlates to OSA
S/s of OSA
Associated sleepiness, fatigue, insomnia, snoring, subjective nocturnal respiratory disturbance, or observed apnea
risk factors for OSA
HTN, CAD, MI, CHF, AF, CVA, DM, cognitive dysfunction, or mood disorder
Obstructive sleep apnea syndrome(OSAS) dx
AHI of ≥ 5
Daytime somnolence ≥ 2 days/week
Severity of OSA
Mild (AHI 5–15)
Moderate (AHI 15–30)
Severe (AHI ≥ 30)
Direct physiologic mechanisms for sleep apnea
Anatomic and functional upper airway obstruction
Decreased respiratory-related EEG arousal response
Instability of the ventilatory response to chemical stimuli
The way Apnea episodes are resolved …….
Increased muscular activity at the upper airway muscles= increased muscular tension
Increased muscular activity at the thoracoabdominal respiratory muscles
EEG arousal
Neurocognitive Consequences of OSA
Slowing of the EEG
Chronic sleep deprivation
Excessive daytime sleepiness (EDS)
Increased number of lapses on psychomotor vigilance task testing
Decrease in cognition and performance
Decreased quality of life
Mood disorders
Increased rates of motor vehicle collisions
MetabolicConsequences of OSA
Hypoxic injury
Systemic inflammation
Increased sympathetic activity
Alterations in hypothalamic-pituitary-adrenal function
Hormonal changes
Insulin resistance
Glucose intolerance
Dyslipidemia
DM 2
Central obesity
Metabolic syndrome
Most common sites of upper airway obstruction
Retropalatal and retroglossal regions of the oropharynx
Causes of Obstructions
Bony craniofacial abnormalities
Excess soft tissue
Acromegaly, thyroid enlargement, and hypothyroidism
tonsils
Functional collapse
Forces that can collapse the upper airway > the forces that dilate the upper airway
collapsing forces ….intraluminal negative inspiratory pressures, extraluminal positive pressure outside the lumen contribute to collapsing
Collapsing forces
Intraluminal negative inspiratory pressure and extraluminal positive pressure
Dilating forces
Pharyngeal dilating muscle tone and longitudinal traction on the upper airway by increased lung volume
Tracheal tug
Supine position enhances airway obstruction by….
Increases the effect of extraluminal positive pressure against the pharynx
gravity
More collapsible upper airwayr/t altered neuromuscular control
causes
Inflammatory infiltrates and denervation changes overtime that makes the upper airway collapse
Respiratory-Related Arousal Response stimulated by
Hypercapnia
Hypoxia
Upper airway obstruction
Work of breathing
most reliable stimulator of breathing
work of breathing = energy expended to inhale and exhale
Clinical Symptoms during the day
Dry mouth or headache upon waking, sleepiness, falling asleep during monotonous situations, subjective impairment of cognitive function
Clinical Symptoms during the night
Frequent awakening, awaking from own snoring w/ choking sensation, loud snoring, observed pauses in breathing during sleep, tachycardia, non-restorative sleep
Goals of CPAP
Eliminate all respiratory events, hypopnea, snoring, apnea so AHI decreases to less than 5 an hour and keep oxygenation > 90%
SX tx for OSA
Tonsillectomy – adults
Maxillomandibular advancement (MMA)- reconstruction of jaw
Uvulopalatopharyngoplasty (UPPP)- removal of extra tissue in the upper-airway
Adenotonsillectomy – children
For every 1-point increase in the Mallampati score, the odds ratio for OSA is increased by…..
For every 1-point increase in the Mallampati score, the odds ratio for OSA is increased by 2.5
STOP-Bang
questionnaire that assess risk of OSA
Acute Upper Respiratory Tract Infection
Infectious (viral or bacterial) nasopharyngitis - 95%
Noninfectious nasopharyngitis – 5% (Allergic or vasomotor in origin)
URISymptoms
Nonproductive cough, sneezing, and rhinorrhea
Bacterial infections
Fever, purulent nasal discharge, productive cough, and malaise
URI Dx
Diagnosis - based on clinical signs and symptoms
Current URI = Delay surgery
Delay surgery - 6 weeks
URIAnesthetic Considerations
Adequate hydration, reducing secretions, and limiting airway manipulation
Nebulized or topical local anesthetic applied to the vocal cords
Airway of choice with URI
LMA > ETT
Adverse respiratory events with URI and anesthesia
Bronchospasm, laryngospasm, airway obstruction, postintubation croup, desaturation, and atelectasis
Asthma
Reversibleairflow obstruction characterized by bronchial hyperreactivity, bronchoconstriction, and chronic airway inflammation
Hereditary
Family history, maternal smoking during pregnancy, viral infections, and limited childhood exposure to highly infectious environments
Status asthmaticus
life-threatening bronchospasm that persists despite treatment
Stimuli Provoking Asthma
allergens
pharm agents; asa, beta antagonist, NSAID, sulfiing agens
infections; respiratory viruses
exercise; attacks follow exertion rather than occurring during it
emotional stress; endorphins and vagal mediation
Infiltration of the airway mucosa caused by
Eosinophils, neutrophils, mast cells, T cells, B cells, and leukotrienes
AsthmaPathogenesis
Specific chronic mucosal inflammation in lower airways
Activation of the inflammatory cascade
Infiltration of the airway mucosa
Bronchi… airway edema
Basement membrane… thickened
Airway walls… thickened and edematous
Inflammatory mediators
Simultaneous areas of inflammation and repair in the airways
Inflammatory mediators
Histamine, prostaglandin D2and leukotrienes
Asthma Signs and Symptoms
Wheezing, productive or nonproductive cough, dyspnea, chest discomfort or tightness (air hunger), and eosinophilia
Episodic disease… acute exacerbations interspersed w/ symptom-free periods
Short-lived attacks lasting minutes to hours
Previous intubation or ICU admission, ≥ 2 hospitalizations in the past year, and the presence of significant co-existing diseases
AsthmaDiagnosis
Airflow obstruction on pulmonary function testing that is at least partially reversible with bronchodilators
Increase in airflow after bronchodilator inhalation
Asthma PFT
FEV1< 35% of normal
FRC - may increase substantially
TLC - within normal range
Asthma ABG
Hypocarbia and respiratory alkalosis - most common
Mild
Normal PaO2and PaCO2
Severe
PaO2<60 mm Hg on RA
PaCO2 increases when the FEV1< 25% of normal
Ashtma CXR
Mild/moderate – normal
Severe - hyperinflation and hilar vascular congestion due to mucus plugging and pulmonary hypertension
congested pulmonary hilum
Asthma ECG
RV strain or irritability, R axis deviation = moderate to severe changes
Short-acting bronchodilators - β2-agonists
Albuterol (Proventil), levalbuterol (Xopenex)
Inhaled corticosteroids
Budesonide (Pulmicort), fluticasone (Flovent)
Long-acting bronchodilators
β2-agonists – arformoterol (Brovana)
Combo inhaled corticosteroids + long-acting bronchodilators
Budesonide + formoterol (Symbicort)Fluticasone + salmeterol (Advair)
Leukotriene modifiers
Montelukast (Singulair)
Anti-IgE monoclonal antibody
Omalizumab
Methylxanthines
Theophylline, aminophylline
Mast cell stabilizer
Cromolyn
mechanical ventilation parameters for asthma
shorter inspiration and longer expiration
avoid auto-peep/ air trapping by prolonging expiration
permissive hypercapnia if needed to avoid barotrauma
Asthma preferred anesthetic / airway
Regional > GA
stay out of the airway
LMA > ETT
suppress airway reflex; Fentanyl, remifentanil
Induction – lidocaine, propofol, ketamine
Chronic Obstructive Pulmonary Disease
Progressive loss of alveolar tissue and progressive airflow obstruction that isnot reversible
α1-Antitrypsin deficiency
Emphysema characterized by
lung parenchymal destruction
Chronic bronchitis is characterized by
cough and sputum production
Risk factors for COPD
Smoking
Occupational exposure to dust and chemicals (coal mining, gold mining, and textile industry)
Indoor and outdoor pollution
Recurrent childhood respiratory infections
Low birth weight
Lung development during gestation and childhood
Lower socioeconomic class
Asthma
Age
Female sex
COPD Signs and Symptoms
Dyspnea on exertion or at rest, chronic cough, and chronic sputum production
Exacerbations… acute worsening airflow obstruction
Tachypnea and prolonged expiratory time
Decreased breath sounds, expiratory wheezes
COPD PFT
FEV1:FVC < 70% of predicted
Increased RV, FRC, and TLC
COPD CXR
Hyperlucency (dark areas), hyperinflation, flattened diaphragm
Bullae = air sacs= emphysema
COPD CT
More sensitive than CXR
COPD ABG
Relatively normal until COPD is severe
PaO2and PaCO2 … based on FEV1
COPD long-term oxygen treatment when…..
PaO2< 55 mm Hg, hematocrit > 55%, or cor pulmonale
Goal - PaO2> 60 mm Hg
relief of arterial hypoxemia w/ o2= effective in decreasing PVR and Pulm htn then drug therapy.
COPDTreatment
Long-actingβ2-agonists, inhaled corticosteroids, and long-acting anticholinergic drugs
Flu and pneumonia vaccinations
Diuretics
treatment for COPD exacerbation
Antibiotics, systemic corticosteroids, and theophylline
Lung volume reduction surgery
Recommended if Not responsive to medical therapy
Regions of overdistended/poorly functioning lung tissue
Normal areas of lung tissue allowed expanding
typical albumin for COPD pts
Albumin <3.5 mg/dL
COPD anesthesia of choice
Regional anesthesia > GA for Lower intraabdominal
Decreases the risk of laryngospasm, bronchospasm, barotrauma, and hypoxemia
Avoid interscalene block- because it can cause hemidiaphragm paralysis
less benzo and opioids
humidity inspired gas
avoid Nitrous oxide= Enlargement or rupture of bullae…pnx
Sevoflurane > Desflurane
Bronchospasm treatment
Volatile anesthetic or propofol
Short-acting bronchodilator
Suctioning secretions
IV corticosteroids and/or epinephrine
Tabacco use…..
Cessation > 8 weeks prior to surgery
Minimum 6 weeks
> 60 pack-years= 2 ppd x 30 yrs
2x the risk of any pulmonary complication
3x the risk of pneumonia
Elimination half-life of carbon monoxide is ……
4-6 hours
Effects within in 12 hours of cessation of smoking
Within12 hours
P50 - 22.9 to 26.4 mm Hg
Carboxyhemoglobin - 6.5% to 1%
Effects within in 6 weeks of cessation of smoking
Improved ciliary and small airway function and decreased sputum production
Return of normal immune function and hepatic enzyme activity
Disadvantages of Smoking Cessation
Increased sputum production
Patient fear of the inability to handle stress
Nicotine withdrawal
Irritability
Restlessness
Sleep disturbances
Depression
