Pulmonary Diagnostic Procedures

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100,000 thoracotomies are performed annually 
Preoperative assessment of risk required


Resectability
The amount of lung tissue than can be safely removed without pulmonary insufficiency.  Depends on pulmonary reserve. 


Operability
Ability of the patient to survive the procedure and perioperative complications.
Depends on Comorbid conditions

2.  Pulmonary Function Testing 

 Pulmonary spirometric studies 
 Pulmonary hemodynamic response testing 
 Exercise testing

3.  Spirometry 

 Modern spirometry is complex and sophisticated 
 Affected by height, age, weight, sex, race and posture 
 Blacks, Polynesians, Asians - lung volumes 10-12% less than similarly aged  whites 
 Main stays of preoperative assessment are arterial oxygenation, spirometry, and  diffusion capacity 
 Spirometry and arterial oxygen not predictive of postoperative complications

4.  Diffusion Capacity 

 Is more sensitive as a predictor of postoperative complications 
 DLCO estimates pulmonary capillary surface area, hemoglobin content, alveolar micro architecture 
 DLCO is decreased in emphysema, pulmonary hypertension and interstitial lung disease 
 DLCO <60% was the best predictor of mortality

5.  Ventilation/Perfusion Scans 

 Useful in determination of postoperative lung function 
 Perfusion scans (Tc99 ) are more predictable than ventilation scans (Xe133) 
 Spirometry and lung scans accurately predict postoperative lung function 
 A calculated postoperative FEV1 of less than 40% of predicted was associated with 50% mortality rate 
 Absolute minimum postoperative FEV1 should be > 800 cc

6.  Pulmonary Hemodynamics Response Testing 

 Not popular in North America 
 Pulmonary artery pressure and resistance determine survival 
 Pulmonary arterial pressure > 35 mmHg results in decreased survival (10 fold) 
 Pulmonary hypertension is a contraindication to lung resection 
 PVR > 190 dynes associated with 90% mortality 
 Unfortunately pulmonary function tests do not identify patients with high pulmonary vascular resistance

7.  Exercise Testing 

 Minimal achievement tests 

  Submaximal effort, not standardized

 Maximum exercise tests 

  Arterial desaturation with exercise 
  Maximal oxygen consumption (MVO2) 
  Blood lactate level during exercise

8.  Guidelines for Patient Selections 

 FVC   < 50% of predicted 
 FEV1  < 50% of predicted 
FEV1 < 2.0 Liters
 DLCO  < 60% of predicted 
PAP > 35 mm/Hg
PVR > 190 dynes
 MVV   < 50% of predicted (with good patient cooperation)

9.  Summary 

Postoperative lung function (based on spirometry and V/Q scans) can be predicted 
In pneumonectomy patients the best predictor of death was calculated postoperative FEV1 
In all patients the best predictor of death was calculated postoperative DLCO 
Best predictor of overall complications was DLCO and predicted postoperative DLCO 

EXTENDED OUTLINE

I. Pulmonary Lympatic Drainage 

  RUL - lower paratracheal   higher paratracheal   neck 
  RML - subcarinal  right paratracheal 
  RLL - subcarinal   right paratracheal 
  LUL - subaortic (Botallo's node)  Anterior mediastinal or left paratracheal 
  LLL - subcarinal 

 - clinical findings often do not correlate with anatomical predictions 

III. Scalene Node Biopsy 

 A. Indicated with a palpable node 
 B. Staging ie. nonpalpable is more controversal 
  1. SNB vs. Mediastinoscopy 
   a. M&M the same 
   b. Yield: SNB - 10% positive, Mediastinoscopy- 30% positive 
 C. Technique 
  - anatomical bonderies include: 
   inferiorly: subclavian vein 
   medially: internal jugular 
   posteriorly: anterior scalene 

IV. Mediastinoscopy 

 A. Positive node 30-35% of the time 
 B.Controversy 
  1. Do patients with suspected cancer who are otherwise operable need this procedure 
  2. What to with a positive node (N2 Disease) 
 C. Studies 
  1. Maassen 
   -1921 cases of Stage I & II 
    central masses - 23% positve nodes 
    peripheral masses - 19% positive 
 D. CT Scan 
  1. Negative predictive rate 80-97% 
  2. Positive predictive rate 44-82% 
  3. Dales: meta-analysis 
   false negative 20% 
   false positive 21% 
  4. Kerr: 15% of positive restricted nodes are less than 10mm 
 E. N2 Disease carries a 5 yr survival of 3% (Mountain et al 28%) 
  1. exceptions: 
   a. limited aortopulmonary nodes and no anterior mediastinal nodes 
   b. non-small cell with limited ipsilateral tracheobroncial intranodal involvement 
 F. Morbidity less than 0.1% 
 G. Technique 

 1. Definition 
      Over 100,000 thoracotomies are performed annually in the United States 
 alone, and preoperative assessment of risk is required. Two concepts are key to risk 
 assessment: resectability, which is the amount of lung tissue than can be safely 
 removed without pulmonary insufficiency, and operability, which is the ability of the 
 patient to survive the procedure and any perioperative complications. Resectability 
 depends on pulmonary reserve and operability depends on comorbid conditions. 
 The main tests for preoperative assessment are arterial oxygenation, spirometry, and 
 diffusion capacity. 
 
2. Arterial Blood Gases 
 · The gas partial pressure in liquid is equal to the barometric pressure times the 
 fractional gas concentration 
 · The solubility of oxygen and carbon dioxide in blood is affected by hemoglobin and 
 buffers 
 · Lower temperature, an increase in pH, and a fall in blood PCO2 will all shift the 
 HbO2 dissocation curve to the left, increasing the affinity of hemoglobin for oxygen 
 · Three points of the curve to remember:

 · CO2 is usually transported as HCO3-, but can combine with hemoglobin and 
 carbonic anhydrase 
 · Venous PCO2 is about 46; arterial and alveolar PCO2 is about 40 
 · Normal alveolar-arterial (A-a) PO2 gradient is 10 in young adults and up to 20 in 
 older adults 
 · Calculate A-a gradient as follows: PAO2 = 150-PaCO2, then subtract the PaO2 
 · Common causes of increased A-a gradient include hypoventilation, reduced inspired 
 oxygen, right-to-left shunting, and V/Q mismatch from atelectasis or airway 
 obstruction 
 · A PaCO2 greater than 45 indicates a higher risk of morbidity and mortality, but 
 hypoxemia is unreliable as a predictor of poor outcome 

 3. Spirometry 
 · Modern spirometry is complex, sophisticated, and is affected by height, age, weight, 
 sex, race and posture 
 · Important values include VT, FEV1, FVC, and FEV1/FVC 
 · In restrictive disease, the total lung capacity, vital capacity, and FEV1 are all 
 reduced, but the FEV1/FVC is normal 
 · In obstructive diseases like emphysema, the total lung capacity and vital capacity are 
 increased, and the FEV1 and FEV1/FVC are reduced 
 · Blacks, Polynesians, and Asians have lung volumes 10-12% less than similarly aged 
 whites 
 · An FEV1 less than 2.0 liters indicates a higher risk of morbidity and mortality 
 
4. Diffusion Capacity 
 · Is more sensitive than spirometry as a predictor of postoperative complications 
 · DLCO estimates pulmonary capillary surface area, hemoglobin content, and alveolar 
 microarchitecture 
 · The test is particularly useful in patients with dyspnea and relatively normal 
 spirometry 
 · DLCO is decreased in emphysema, pulmonary hypertension and interstitial lung 
 disease; it is increased in mitral stenosis, left-sided failure, and polycythemia 
 · A DLCO less than 60% is a good predictor of mortality 

 5. Ventilation/Perfusion Scans 
 · Blood flow (perfusion) is absent in pulmonary vascular obstruction and ventilation is 
 absent in atelectasis 
 · The perfusion portion (Tc99) is more predictable than the ventilation portion 
 (Xe133) 
 · When used together with spirometry, lung scans can accurately predict postoperative 
 lung function 

 6. Pulmonary Hemodynamics Response Testing 
 · Pulmonary artery pressure and resistance are determinants of survival 
 · A pulmonary arterial pressure greater than 35 mmHg results in a 10-fold decreased 
 survival 
 · Pulmonary hypertension is a contraindication to lung resection 
 · PVR greater than 190 dynes is associated with 90% mortality 
 · Unfortunately, pulmonary function tests do not identify patients with high pulmonary 
 vascular resistance 

7. Exercise Testing 
 · Maximal oxygen consumption (MVO2) may be useful in evaluating marginal patients 
 · Elevated blood lactate level during exercise may help predict mortality, but is not 
 useful for postoperative complications 

 8. Guidelines for Patient Selections 
        FVC     Less than 50% of predicted 
        FEV1    Less than 50% of predicted 
        DLCO   Less than 60% of predicted 
        MVV    Less than 50% of predicted (with good patient cooperation) 

 9. Bronchoscopy 
 A. Indications 
 · A wide range of diseases are indications for either diagnostic or therapeutic 
 bronchoscopy, most commonly carcinoma, pulmonary infections, and interstitial lung 
 disease 
 · The surgeon must perform bronchoscopy prior to thoracotomy on any patient who 
 may undergo pulmonary resection 
 · Specific indications for the procedure include chronic, persistent cough; hemoptysis; 
 localized wheezing; and bronchial obstruction 

 B. Diagnostic Bronchoscopy 
 · An 8 x 40mm rigid bronchoscope is suitable for most adults 
 · The flexible bronchoscope is useful for peripheral or upper lobe lesions, but is limited 
 in the presence of thick secretions and excessive bleeding 
 · Either topical or general anesthesia may be used depending on patient status and age 
 · As the tip of the bronchoscope passes the larynx, the patient's head is lowered and 
 extended 
 · Use ball-tip or cup forceps for tissue sampling, and always biopsy proximal to a 
 gross tumor to define the upper limit of the tumor 
 · Flexible bronchoscopy allows for transbronchial needle biopsy, washings, and 
 brushings 

 C. Therapeutic Bronchscopy 
 · Most foreign bodies can be removed by bronchoscopy; grasping forceps or a 
 Fogarty catheter are the most useful 
 · Heavy retained secretions can usually be drained using flexible bronchoscopy with a 
 large side port 
 · Palliation resection of endobronchial obstructing tumors can be done with the 
 Nd:YAG laser 
 · Other treatments include brachytherapy and phototherapy 

 D. Specific Conditions 
 · Bronchogenic carcinoma can present as an endobronchial mass, submucosal or 
 peribronchial involvement, a peripheral mass, diffuse metastatic disease, or occult 
 tumor 
 · Masses and metastatic disease should be directly biopsied, while submucosal 
 involvement and peripheral masses requires transbronchial needle biopsy, washings 
 and brushings 
 · Occult tumors are discovered from positive sputum cytology; a thorough 
 bronchoscopic examination will find the majority of these lesions 
 · Bronchoscopy is also useful for tuberculosis, fungal infections, and opportunistic 
 infections in the immunocompromised patient