Thoracic I Flashcards
1
Q
What is meant by a resectable lung cancer? Operable patient?
A
- Patient with resectable lung Ca has a diseases that is still local or locoregional in scope, and can be encompassed in a plausible surgical procedure
- An operable patient is someone that can tolerate the proposed resection with acceptable risk
2
Q
What are some complications from thoracic surgery?
What are patient risk factors for increased complications?
How can you decrease respiratory complications in high-risk patients?
A
-
Pulmonary morbidity: leading cause of complications following thoracic surgery
- Occurance: 15-20% thoracic sx pts
- Mortality: 3-4%
-
Cardiac: 10-15% thoracic sx patients
- Arrythmias: commonly atrial
- Ischemia → 5% (peak risk POD 2 & 3)
-
Other Complications:
- Atelectasis
- Pneumonia
- Respiratory failure (wean failure)
-
Patient Risk Factors:
- advanced age
- poor general health status
- COPD
- BMI > 30 kg/m2 (obesity)
- low FEV1
- low predicted postop FEV1
-
Decrease Respiratory Complications in HIGH RISK pts:
- Smoking cessation
- Physiotherapy prior to sx
- Thoracic epidural analgesia
3
Q
What is a key question to ask prior to thoracic surgery?
What are 3 elements to preoperative assessment of lung function for thoracic cases?
A
- Key question: Is this operable?
- Will the patient tolerate resection with acceptable risk?
- 3 elements:
-
Lung mechanical function
-
Most valid test: Predictive Postop FEV1 (ppoFEV1)
- Increased risk → < 30-40%
-
Most valid test: Predictive Postop FEV1 (ppoFEV1)
-
Pulmonary parenchymal function
-
Most valid test: Predictive Postop Diffusing Capacity (ppoDLCO)
- Increased risk → < 30-40%
- Parenchymal tissue → “gas exchanging tissue”
- Increased risk → < 30-40%
-
Most valid test: Predictive Postop Diffusing Capacity (ppoDLCO)
-
Cardiopulmonary reserve
-
Most valid test: Maximal Oxygen Consumption
- Increased risk → < 15 ml/kg/min
-
Most valid test: Maximal Oxygen Consumption
-
Lung mechanical function
4
Q
Summary of the preop assessment?
What are the 4 m’s you should consider for cancer patients?
A
(4 things to consider prior to sx)
-
All patients: Assess
- Exercise tolerance
- Estimate ppoFEV1%
- Discuss postop analgesia
- d/c smoking
-
If ppoFEV1% < 40% pts:
-
Obtain testing →
- DLCO (diffusion capacity for carbon monoxide)
- V/Q scan
- VO2max
-
Obtain testing →
-
Cancer pts:
- Consider the four M’s:
- Mass effects
- Metabolic effects
- Metastases
-
Medications
- Ex:
-
Bleomycin → use loest FiO2 and closely monitor oximetry
- exacerbates O2-inducted pulmonary toxicity
-
Cisplatin → do not admin NSAIDs
- Elevation of serum creatinine
-
Bleomycin → use loest FiO2 and closely monitor oximetry
- Ex:
- Consider the four M’s:
-
COPD pts:
- Arterial blood gas
- Physiotherapy
- Bronchodilators
-
Increased renal risk:
- Creatinine
- BUN
5
Q
How do we appropriately assess the respiratory system prior to thoracic surgery? What laboratory tests and diagnostics are pertinent?
A
-
History & Physical Examination
- Inspection, palpation, auscultation, percussion
-
Exercise tolerance:
-
**primary determinant of outcome in older patients
- Preop exercise capacity is BEST predictor of postthoracotomy outcome in older pts.
- Formal exercise testing required for:
- Unable to give reliable history (or)
- Limited ability to climb stairs bc comorbidities
- ⇓ risk: Ability to climb > 3 flights
- ⇑risk: unable to climb 2 flights
- *QOL measures alone have poor correlation w/ FEV1, DLCO, and exercise testing and should not substitute actual testing → get testing
-
**primary determinant of outcome in older patients
-
Laboratory Tests
- Routine labs
- H/H
- Coags
- Chemistry
- sputum gram stain
- culture and cytology
- LFTs
- ABG’s
- Renal: BUN, Cr
-
Predictive factors for renal dysfx:
- Preop HTN
- ARBs
- Hydoxyethel starch
- Open thoracotomies
-
Predictive factors for renal dysfx:
- Routine labs
- Diagnostics
- Chest Radiograph
-
Pulmonary Function Testing
- How operational or functional will the remaining lung be after resection.
- Pre-op bronchoscope → evaluate tumor/bx of bronchial nodes
6
Q
What CXR findings have specific anesthesia implications?
A
- CXR → MOST USEFUL predictor of DIFFICULT endobronchial intubation
Some radiographic findings have specific anesthesia implications:
-
Tracheal deviation and obstruction
- difficulty with intubation or ventilation
-
Mediastinal mass
- Ventilation difficulty → can compress AW
- dangerous to cease spontaneous ventilation
- Superior vena cava syndrome
- PA compression
- Ventilation difficulty → can compress AW
-
Pleural Effusions
- ⇓ VC
- ⇓FRC
-
Cardiac enlargement
- HF pts → don’t do well with one-lung vent d/t V/Q mismatching
- susceptible to depressant effects of heart
- HF pts → don’t do well with one-lung vent d/t V/Q mismatching
-
Bullous cyst
- PPV → risk for pneumothorax
- prone to rupture
- PPV → risk for pneumothorax
-
Parenchymal reticulation consolidation (pneumonia)
- prone to atelectasis, edema, respiratory fx postop
7
Q
What are some types of pulmonary function testing?
A
- Classifications:
- Tests assessing abnormalities of gas exchange:
-
ARTERIAL BLOOD GAS- review interpretation
- ROME
-
PULSE OXIMETRY- review
- based on Beer Lambert law
- Wavelength for pulse ox is 660 (deoxyhgb- red light) and 940 nm (oxyhgb- infrared light)
- light emission frequencies
- based on Beer Lambert law
- CAPNOGRAPHY- review phases of capnogram and normal and abnormal waveforms (see picture)
-
Ventilation Perfusion Scintigraphy: V/Q scan
- Function/nonfunctional tissues
-
ARTERIAL BLOOD GAS- review interpretation
- Tests assessing mechanical dysfunction of lungs and chest wall (respiratory mechanics)
-
SPIROMETRY
- Required for all patients undergoing pulmonary resection
-
SPIROMETRY
- Tests assessing abnormalities of gas exchange:
8
Q
What is the goal of spirometry?
A
- Primary goal: recognize high or prohibitive risk pts for postop pulmonary complications
- ppoFEV1
- ppoDLCO
- Identify patients who will benefit from aggressive perioperative pulmonary therapy
- Ex: maximal bronchodilators
- Smoking cessation
- Nutritional/exercise programming
- Identify those in whom surgery should be avoided entirely
- Ex: ppoFEV1 or ppoDLCO = < 20%
- High risk → think about R vs B (video assisted?)
- Ex: ppoFEV1 or ppoDLCO = < 20%
- NO single test or combination of tests will definitively predict which patients will develop postoperative pulmonary complications
9
Q
What surgical patients need PFTs preop?
Why do we do PFTs?
A
WHO Needs PFTs ?
- evidence of COPD
- Smokers w/ persistent cough
- Wheezing or Dyspnea hx
- Restrictive Lung disease:
- Chest wall
- Spinal deformities
- Morbidly obese
- esp. those with coexisting lung dx
- Upper abdominal surgery candidates
- Thoracic surgery candidates (open)
- > 70 yo
Why Test?
Identifies patients with abnormal lung function
- Improves the outcome of patients at risk
- Reduces incidence of post-operative respiratory and ventilatory compromise
- Resolves questions about resectability
10
Q
What are the components of phase I PFT testing?
A
Two Components:
- Detect abnormalities of gas exchange
- Detect abnormalities of:
- lung size
- chest wall
- mechanical aspects of ventilation (air flow)
- PFT
- Standardized measurement of pt’s:
- Airflow
- Lung volumes
- DLCO
- Reported as percentage of predicted normal value
- Based on AGE and HEIGHT
- Used in combo w/ H&P, blood gas, CXR, & PFTs
- Facilitate classifications of resp dx into:
- Obstructive
- Restrictive
- Mixed disorder
- Facilitate classifications of resp dx into:
- Standardized measurement of pt’s:
11
Q
What are some values reported from a PFT?
A
These are all effort dependent and require a cooperative, motivated patient:
- Forced expiratory volume in 1 second (FEV1)
- Forced vital capacity (FVC)
- Ratio of FEV1 and FVC, or FEV1/FVC ratio.
- FVC may be normal or decreased as a result of respiratory muscle weakness or dynamic airway obstruction.
- FEF 25–75 (Forced expiratory flow at 25% to 75% of FVC)
- Ex: ⇓FEF 25–75 = collapse of the small airways
- *sensitive indicator → early airway obstruction
12
Q
What is the definition of:
Tidal volume?
Inspiratory reserve volume?
Expiratory reserve volume?
Residual Volume?
TOtal lung capacity?
Vital capacity?
Inspiratory capacity?
Functional residual capacity? What reduces FRC?
A
- Tidal volume (TV)
- Volume of air inhaled and exhaled with each normal breath.
- Inspiratory reserve volume (IRV)
- volume of air that can be maximally inhaled beyond a normal TV.
- Expiratory reserve volume (ERV)
- maximal volume of air that can be exhaled beyond a normal TV.
- Residual volume (RV)
- volume of air that remains in lung after maximal expiration
- Total lung capacity (TLC)
- TLC = IRV + TV + ERV + RV (sum)
- Vital capacity (VC)
- VC = IRV + TV + ERV (sum)
- Does not include RV
- VC = IRV + TV + ERV (sum)
- Inspiratory capacity (IC)
- IC = IRV + TV (sum)
- Functional residual capacity (FRC)
- volume of air in lung at the end of a normal expiration
- FRC = RV + ERV (sum)
- volume of air in lung at the end of a normal expiration
-
Reduction of FRC:
- moving from upright to supine position → ⇓ FRC ~ 1 L
- Induction of anesthesia → further decreases the FRC ~ 0.5 L.
13
Q
What is total lung capacity? When is it increased? Decreased?
A
-
TLC= gas volume in lung after a maximum inspiration
- Normal: 6 - 8 L
-
Increased TLC → COPD
- COPD: 10-12 L
- Causes:
- overexpansion of alveoli or
- destruction of alveolar wall
-
Decreased TLC → restrictive lung disease
- reflecting the degree of fibrosis
- low as 3- 4 L
14
Q
What is residual volume?
A
- Following maximum expiratory effort
- some air is left in lung
- RV = ~ 2 L
- some air is left in lung
- Usually no region develops collapse because distal airways close before alveoli collapse
- Distal AWs → < 2 mm diameter
- Distal AW collapse BEFORE alveoli collapse → so keeps them open (also surfactant fx)
- Distal AWs → < 2 mm diameter
- Limitation:
- How much compression of →
- chest wall
- rib cage
- diaphragm
- How much compression of →
15
Q
What is vital capacity?
What is predictive value based on? What is normal VC?
When is VC decreased?
A
- Deep maximal inspiration followed by maximal exhalation – “slow and relaxed”
- Most common measurement of lung function
- Measurements:
- VC = IRV + TV + ERV or
- VC = TLC – RV
- Predicted values vary:
- Height
- Age
- Sex
- NORMAL: >/=80% of predicted value
- VC decreased:
- From sitting to supine position
- Restrictive lung disease
- Reflects lung volume loss
- Ex: constricting (shrinking) effects of fibrosis
- Reflects lung volume loss
- Obstructive lung disease
- Long term air trapping → increases RV
- Larger RV → encroaching on/reduces VC
- association w/ a proportionally smaller increase in FVC
- Long term air trapping → increases RV
16
Q
What is forced vital capacity?
What is normal?
A
- Maximal inspiration followed by rapid forceful exhalation
- Reflection → flow resistance in airway
- Normal/Healthy pts → little/no difference b/t VC and FVC
- Should be same in healthy patient!
- Air trapping → major difference b/t VC and FVC
- Small AW collapse and air trapping
- Normal/Healthy pts → little/no difference b/t VC and FVC
- Reflection → flow resistance in airway
- Considerations:
- Exhalation → measured as a function of volume/time.
- Effort + cooperation dependent
-
Interpretation of % predicted:
- Normal: 80-120%
- Mild: 70-79%
- Moderate: 50%-69%
- Severe: < 50%
17
Q
FRC in healthy lungs?
COPD?
Fibrotic lung?
Lung resection?
A
Healthy Lungs
- Tidal volume (VT, usually 0.5 L) is inspired from the resting lung volume reached at end-expiration (FRC, 2.0 L).
- With increased ventilation, as in exercise →
- VT is increased
- FRC may be reduced by approximately 0.5 L.
Old/COPD lungs → ⇑ FRC
- FRC increases w/ age as elastic lung tissue is lost
- → this reduces lung recoil force countering the outward chest wall force → the lung assumes a higher volume.
- The rate of this aging process is accelerated in COPD because of the contributions of chronic air trapping and marked loss of elastic tissue.
Fibrotic Lung Disease → ⇓ FRC
- sometimes to 1.5 L
Lung Resection →⇓ FRC
- Compensatory Emphysema → remaining lung will expand to fill the lung tissue void partially
Airway Obstruction
- Exhalation is impeded such that inspiration commences before the usual resting lung volume is reached; thus end-expiratory volume is increased. Such air trapping reduces the resistance to gas flow in the narrowed airways, but because the lung tissue is hyperinflated and mechanically disadvantaged, the work of breathing overall is increased.
18
Q
What is FEV1?
A
-
FEV1 = forced expiratory volume in 1st second of FVC measurement
-
Normal: 75-80% of FVC (declining with age)
- Effort and cooperation dependent
-
Normal: 75-80% of FVC (declining with age)
- Useful assessment!
- Good assessment for COPD severity
-
Most valid test for postop respiratory complications: (equation)
- ppoFEV1 %= preoperative FEV1 % × (1 −% functional lung tissue removed/100)
19
Q
How is COPD categorized?
A
American Thoracic Society categorizes:
-
Stage I: FEV1 > 50% predicted
- Should not have significant dyspnea, hypoxemia, or hypercarbia
- Stage II: FEV1 35-50%
-
Stage III: FEV1 < 35%.
- Stage II or III COPD → have an elevated PaCO2 at rest.
20
Q
What is the FEC1/FVC ratio?
A
- Most useful as a ratio → FEV1 /FVC
- *more direct indication of AW obstruction*
- Considerations:
- Look at % of predicted value than actual result (L)
- Looks at age & size of pt (same number may have different implication in another)
- Diagnostic tool:
- Useful in differentiating b/t restrictive and obstructive dx
-
Restrictive: (both ⇓ proportionally) → normal ratio
- FEV1: ⇓
- FVC: ⇓
-
Obstructive: → low ratio
- FEV1: ⇓⇓(significant drop)
- FVC: normal (?)
-
Restrictive: (both ⇓ proportionally) → normal ratio
- Useful in differentiating b/t restrictive and obstructive dx
- FEV1/FVC % interpretation:
- Normal: > 75%
- Mild: 60%-75%
- Moderate: 50-59%
- Severe obstruction: <49%
21
Q
What is forced expiratory flow 25-75%?
A
-
Forced expiratory flow 25-75% (FEF25-75)
- Mean forced expiratory flow during middle of FVC
- May reflect effort independent expiration and the status of the small airways
-
Sensitive in early stages of obstructive disease
- More reliable than FEV1/FVC
-
Forced expiratory flow 25-75% (FEF25-75)
- Interpretation of % predicted:
- >60% Normal
- 40-60% Mild
- 20-40% Moderate
- <10% Severe obstruction
22
Q
What is the FVC, FEV1, FEV1/FVC% in obstructive dx?
Restrictive?
Muscle weaknesS?
A
- Obstructed lung dx:
- FEV1: decreased
- FVC: normal
- Ratio → decreased
- Restricted lung dx: both ⇓
- FEV1: decreased
- FVC: decreased
- Ratio → normal (even though its not normal lung dx!)
- Muscle weakness: both ⇓
- FEV1: decreased
- FVC: decreased
- Ratio → normal
23
Q
What is maximum voluntary ventilation?
What factors affect MVV?
A
- Largest volume that can be breathed per minute by voluntary effort
- Requires high rate of air flow
- changes in airway resistance alter MVV
- Diagnostic use:
- Obstructive dx: ⇓ MVV
- Restrictive disease: normal MVV
- MVV correlates w/ FEV1
- FEV1 x 35~ MVV
- Normal: > 50% of predicted values
Factors Affecting MVV
- Patient effort (motivation, coordination)
- Elastic properties of the lung
- Chest wall abnormalities
- Respiratory muscle strength issues
FEV1, FVC, and MVV → cooperation!
24
Q
What is closing volume?
A
- The lung volume at which airways begin to close or stop contributing to the expired gas
-
Normal: 15-20% of VC
- ** in healthy pt/sitting position**
-
Smokers: ⇑ CV
- Reflects loss of elastic recoil and/or small airway pathology
-
Normal: 15-20% of VC
25
Q
What is VO2max?
A
- Maximum oxygen consumption (VO2max) during exercise testing
- ⇓ by 4% during exercise → high risk
-
Values:
-
VO2max: > 20 ml/kg/min
- Most have no pulm complications
-
High risk → < 15 mL/kg/min (preop)
- High M&M
- Very high risk → < 10 ml/kg/min
-
VO2max: > 20 ml/kg/min
-
Testing: 6-minute test
- Requires little/no lab equipment
- VO2max can be estimated from 6-minute walk test: [distance walked (meters) / 30] = VO2max
- 6 min walk (~450 m) → estimated VO2max = 450/30 = 15 mL/kg/min
- Examples: VO2max
- 5 flights = > 20 mL/kg/min
- 2 flights = 12 mL/kg/min.
- ⇑ risk → SpO2 decrease > 4%
- Examples: VO2max
- 6 min walk (~450 m) → estimated VO2max = 450/30 = 15 mL/kg/min
26
Q
What is DLCO?
A
Diffusing Capacity (ppoDLCO)
- Diffusing capacity (DLCO) is the ability of the lung to perform gas exchange (pt. inhales carbon monoxide and tested)
-
High risk → < 40% of postop predicted value
- correlates with both increased respiratory and cardiac complications
- independent of FEV1 (even if FEV1 normal)
- correlates with both increased respiratory and cardiac complications
-
DLCO (not FEV1) → negatively affected by preoperative chemotherapy
- may be the most important predictor of complications in this subgroup of patients.
- Some authors feel a higher cutoff risk-threshold for ppoDLco of < 50% may be more appropriate.
- Measured- CO inhalation
-
High risk → < 40% of postop predicted value
27
Q
How do you predict postop pulmonary function?
A
- One method of estimating the percent of functional lung tissue is based on a calculation of the number of functioning subsegments of the lung removed
- Right lung: 3 lobes
- Left lung: 2 lobes
- Number of subsegments of each lobe is used to calculate the predicted postoperative (ppo) pulmonary function (picture →)
- ppoFEV1 = preop FEV1 (or DLco) % × ( 1 – segment % /100)
- Ex: After a RLL lobectomy
- Taking 12 segments out of 42 segments → 12/42= 29%
- Taking out 29% of total lung tissue
- Equation:
- Given: Preop FEV1 [or DLco] 70% of normal
- 70% × ( 1 − 29/100) = 50% ppoFEV1
- Taking 12 segments out of 42 segments → 12/42= 29%
-
Postresection respiratory complications:
-
ppoFEV1:
- low risk = > 40%
- risk = < 40% (complications)
- high risk = < 30%
- unacceptably high risk = < 20%
-
ppoFEV1:
28
Q
How do we estimate operative risk?
A
- ALWAYS asses Functional Capacity
- Functional capacity > 2 METS → need spirometry
- *ppoFEV1
- *ppoDLCO
- > 60% (both) → pt should do well
- 30-60% → 6 min walk test (get VO2max)
- 6 min walk test
- Walk > 400 m → proceed to sx
- Walk < 400 m → get exercise testing and formally calculate O2 consumption
- > 10 ml/kg/min → increased risk
- < 10 ml/kg/min → hold sx and optimize (consider video thoracoscopy)
- Functional capacity > 2 METS → need spirometry
- Traditionally arterial blood gas data such as PaO2 less than 60 mm Hg or PaCO2 greater than 45 mm Hg have been used as cut-off values for pulmonary resection. Cancer resections have now been successfully done or even combined with volume reduction in patients who do not meet these criteria, although they remain useful as warning indicators of increased risk.
29
Q
What are flow volume loops?
A
- Bottom curve- inspiratory effort
- O: obstructive dx (baby carriage)
- R(E): extraparenchymal dx
- Limitation in inspiratory and expiration
- R(P): parenchymal restrictive disease
- RV: Residual volume;
- TLC: total lung capacity.
- By convention, lung volume increases to the left on the abscissa. The arrow alongside the normal curve indicates the direction of expiration from TLC to RV
- Forced expiration is plotted in all conditions
- Forced inspiration is shown only for the normal curve.
30
Q
What will a flow volume look like with upper airway lesions?
Extrathoracic obstruction?
Intrathoracic obstruction?
A
-
Upper airway lesions
- Ex: tracheal stenosis
- Appearance: fixed plateau during inspiration and expiration
- FEF50 /FIF50 ratio: unchanged
-
Extrathoracic obstruction
- Ex: lesion/tumor located above sternal notch
- Appearance: flattening of inspiratory loop
- Flattening → represents no further increase in airflow bc mass causes AW collapse
- FEF50 /FIF50 ratio: > 1
-
Intrathoracic obstruction
- Appearance: flattening of expiratory loop
- Flattening → lesion causes AW collapse during expiration
- FEF50 /FIF50 ratio: < 1
- Appearance: flattening of expiratory loop
32
Q
What factors characterize average risk? Elevated risk?
A
- Average risk
- FEV1>2 L or 80% predicted
- PPO FEV1 >80$ predicted
- PPO FEV1 + PPO DLCO both >40%
- VO2 max >15 ml/kg/min
- ability to climb 3 flights stairs
- Elevated risk
- FEV1 <2L or <40% predicted
- PPO FEV1 <40% predicted
- PPO DLCO <40% predicted
- VO2 max <10 mL/kg/min (on 6 min walk test)
- inability to climb one flight stairs
- o2 desat >4% during exercise
The National Emphysema Treatment Trial:
- preoperative FEV1 or DLCO < 20% → unacceptably high perioperative mortality rate.
- These can be considered as the absolute minimal values compatible with a successful outcome.
33
Q
Preop eval of patients for pulmonary sx?
A
- Evaluate comorbidities
- Smoking related complications (CAD?)
- Cor pulmonale
- Paraneoplasm effects
- Secreting hormones?
- CV dx
- MI w/in 6 wks?
- Chemo
- EKG/CXR
- Labs
- Lung function testing:
- FEV1 and DLCO
- VO2max
- COPD → blood gas and response to bronchodilators
36
Q
What are some recommendations for prevention of postop a fib in thoracic sx?
A
- Consider those at highest risk for A fib:
- anterior mediastinal mass
- Lobectomy
- Pneumonectomy
- Esophagectomy
- Diltiazem (if preserved CV fx and not taking BB)
- Amiodarone
- Statins
- All patients:
- Continue BB preop
- Magnesium level
- Optimize
37
Q
What is the CV response to COPD and CAD?
Consideration for tmanagement in thoracic surgery patients?
A
- CV response to COPD & CAD → pHTN
-
Pulmonary hypertension- 40-50% pts w/ severe lung disease
- Increased pulmonary vascular resistance
- Right ventricular hypertrophy and dilation
- LV dysfunction due to CAD, MI, HTN
- Vascular Resistance measurements – PA, PAOP/PCWP, C.O., PV Compliance
- PAP (pulm artery pressure) > 25 or systolic >35:
- Increased risk respiratory complications
- prolonged intubation
- PAP (pulm artery pressure) > 25 or systolic >35:
- Management:
- ECG/ECHO
- Needed to determine severity of associated CV disease/pulm HTN
-
AVOID HoTN
- *vasopressin to maintain BP
- ECG/ECHO
- After pulmonary resection → right ventricular dysfunction proportional to the amount of functioning pulmonary vascular bed that has been removed.
- The exact etiology and duration of dysfx unknown.
- Hemodynamic problem minimal when the patient is at rest
-
Dramatic when exercises → leading to:
- elevation of pulmonary vascular pressures
- limited CO
- absence of normal decrease in PVR usually seen with exertion
-
Dramatic when exercises → leading to:
Management of pHTN secondary to Lung Disease (chart →)
- 2 main types of pHTN we focus on:
- pHTN d/t left heart disease
-
*pHTN d/t lung disease
- noncardiac surgery more likely to have pHTN due to lung disease
- Paravertebral blocks preferred over thoracic epidural in this population
- May need PA cath to monitor pressures (CO)
40
Q
What are come cardiac and respiratory effects of smoking?
Smoking cessation guidance prior to surgery?
A
-
Cardiac effects of smoking:
- Risk factor for developing CV dx
- Carbon monoxide →
- decreases O2 delivery
- increases myocardial work
- Releases catecholamines → coronary vasoconstriction
- Exercise capacity decreases
-
Respiratory effects of smoking:
- Risk factor for developing pulm dx
- Mucocilliary activity decrease
- Hyperreactive AW
- Pulm immune fx decrease
-
Smoking cessation:
- > 4 wks d/c smoking → Pulmonary complications⇓
- > 12 hrs d/c smoking → Carboxyhgb [] ⇓
- There is no rebound increase in pulmonary complications if patients stop for shorter (< 8 weeks) periods before surgery. Intensive smoking-cessation interventions are the most successful.
-
Important to avoid smoking postop
- Smoking leads to prolonged period of tissue hypoxemia.
- Wound tissue oxygen tension correlates with wound healing and resistance to infection.
41
Q
What are some common COPD meds patients may be taking?
A
- B adrenergic agnoists (ie albuterol, terbutaline)
- increase adenylate cyclase-→ increase cAMP→ decrease smooth muscle tone→ bronchodilation
- Methylxanthines (ie aminophyllin, theophylline)
- phosphodiesterase inhibition→ increase cAMP→ potentiates endogenous catecholamine
- improve diaphragmatic contracility, central respiratory stimulant
- phosphodiesterase inhibition→ increase cAMP→ potentiates endogenous catecholamine
- Corticosteroids (ie methylprednisolone, dexamethasone, cortisol)
- antiinflammatory, membrane stabilizing, inhibits histamine release
- potentiates b agonists
- Anticholinergic (ie glyco, ipratropium)
- blocks acetylcholine at postganglionic receptors, decrease cGMP, relaxes airway smooth muscle
- Antileukotriene (ie montelukast)
- inhibit leukotriene production
- antiinfallmatory
- used in addition to steroids
- inhibit leukotriene production
49
Q
What are some differnces in spirometry values with obstructive lung dx?
A
- RV ⇑
- FRC ⇑
- TLC – normal/⇑
- RV:TLC ⇑
55
Q
Common drugs to treat asthma and MOA?
A
57
Q
Spirometry values with restrictive dx?
A
- Decreased TLC
- Vital Capacity < 70 ml/kg
- Expiratory flow rate normal
- FEV1/FVC ratio NORMAL
- Rapid, shallow breathing pattern
- Increased PaCo2
- Decreased lung compliance
- Increased work of breathing
- Conditions that interfere with normal lung expansion during inspiration
Spirometry → all volumes reduced
62
Q
4m’s to consider with lung Ca??
A
