UBP 5.5 (Short Form): Pulmonary – Pneumonectomy

Question 1

What would you include in your pre-anesthetic assessment?

(You are performing the pre-anesthetic assessment for a 68-year-old male with small cell carcinoma of the lung, scheduled for a left pneumonectomy in 2 weeks. He complains of dyspnea on exertion and uses supplemental oxygen at night. Past medical history includes COPD, asthma, HTN, peripheral vascular disease, and a 50 pack-year smoking history. Physical exam reveals digital clubbing and moderate expiratory wheezing. Medications include HCTZ, theophylline, Advair, ASA, home oxygen, and albuterol prn. HR = 70, BP = 172/88 mmHg, SpO2 = 90%, Temp = 36.4 °C, Hct = 58.)

Answer 1

I would perform a history and physical exam to identify signs and symptoms of –

• coronary artery disease,
• potential myocardium at risk, and
• end organ damage from chronic hypertension and/or peripheral vascular disease.

I would also perform a careful airway exam, and assess his cardiopulmonary and renal function.

–

Considering his lung cancer, I would:

1. order and/or review imaging studies
   
   • (i.e. chest CT, posterior and anterior chest x-rays),
2. evaluate the patient for signs of –
   
   • mass effect
     
     • (obstructive pneumonia, SVC syndrome, Pancoast’s syndrome, and tracheobronchial distortion),
   • tumor invasion of the respiratory tract
     
     • (i.e. history of blood-stained sputum or frank hemoptysis), and/or
   • metastases,
3. identify any metabolic abnormalities,
4. consider the implications of any cancer related medications the patient was taking, such as –
   
   • bleomycin (i.e. interstitial pneumonitis or pulmonary fibrosis) or
   • cisplatin (i.e. peripheral neuropathy and renal failure), and
5. determine if he is suffering from any paraneoplastic syndromes (e.g. Lambert-Eaton Myasthenic Syndrome).

To further evaluate the severity of the patient’s pulmonary disease (COPD, asthma, history of smoking, lung cancer), the risk of postoperative pulmonary complications, and his tolerance of left pneumonectomy, I would:

1. order or review – recent PFTs (pre and post-bronchodilator therapy), an ECG, chest x-rays, a chest CT, and an ABG;
2. examine the patient to identify any –
   
   • cyanosis (indicates a limited margin of respiratory reserve),
   • digital clubbing (associated with chronic lung disease, cyanotic heart disease, and lung cancer), and/or
   • dyspnea (occurs when ventilator requirements exceed the patient’s ability to respond appropriately);
3. evaluate the patient, chest x-rays, and ECG for any signs of pulmonary hypertension
   
   • (COPD leads to distended pulmonary capillary beds, with subsequent intolerance to increased pulmonary blood flow),
   • such as a narrowly split heart sound, a loud second heart sound (pulmonic valve closure), and right ventricular and/or atrial hypertrophy; and
4. perform a pre-thoracotomy respiratory assessment by evaluating his respiratory mechanics (i.e. FEV₁, MVV, RV/TLC, FVC), lung parenchymal function (i.e. DLCO, PaO2, PaCO2), and cardiopulmonary reserve (i.e. VO2 max, Stair Climbing, 6 Minute Walk Test, Exercise SpO2).
5. Furthermore, if his ppoFEV₁% were < 40%, I would – order a V/Q scan to assess the preoperative contribution of the lung to be resected (helps to more accurately predict post-resection pulmonary function), and
6. utilize echocardiograpy to evaluate his right ventricular function (echocardiography should be ordered for COPD patients with a ppoFEV₁% < 40%, since they are high risk of developing right heart failure following pneumonectomy).

Question 2

How would PFTs be helpful?

(You are performing the pre-anesthetic assessment for a 68-year-old male with small cell carcinoma of the lung, scheduled for a left pneumonectomy in 2 weeks. He complains of dyspnea on exertion and uses supplemental oxygen at night. Past medical history includes COPD, asthma, HTN, peripheral vascular disease, and a 50 pack-year smoking history. Physical exam reveals digital clubbing and moderate expiratory wheezing. Medications include HCTZ, theophylline, Advair, ASA, home oxygen, and albuterol prn. HR = 70, BP = 172/88 mmHg, SpO2 = 90%, Temp = 36.4 °C, Hct = 58.)

Answer 2

Although a careful history and physical can provide a great deal of information concerning this patient’s respiratory function,

the evaluation of respiratory mechanics and volumes via PFTs can help to determine –

• the severity of his COPD,
• identify those patients who might benefit from bronchodilator therapy,
• predict post-pneumonectomy pulmonary function, and
• identify those at increased risk of post-operative pulmonary complications.

While there are many pulmonary function tests, the best tests for pre-thoracotomy assessment are the –

• ppoFEV₁ (respiratory mechanics), the
• DLCO (lung parenchymal function), and the
• VO2 max (cardiopulmonary reserve).

• (Per Dr. Gallen –* you want to see ppoFEV₁ and ppoDLCO, the #’s are well associated with how well patient will do.
• if ppoFEV₁ and ppoDLCO is > 60* %, pt has low likelihood of morbidity and mortality.
• If (<60%) or ~= 30%, need additional testing.*
• If < 30%, NOT good to do surgery.)*

Question 3

What is the significance of his digital clubbing and elevated Hct?

(You are performing the pre-anesthetic assessment for a 68-year-old male with small cell carcinoma of the lung, scheduled for a left pneumonectomy in 2 weeks. He complains of dyspnea on exertion and uses supplemental oxygen at night. Past medical history includes COPD, asthma, HTN, peripheral vascular disease, and a 50 pack-year smoking history. Physical exam reveals digital clubbing and moderate expiratory wheezing. Medications include HCTZ, theophylline, Advair, ASA, home oxygen, and albuterol prn. HR = 70, BP = 172/88 mmHg, SpO2 = 90%, Temp = 36.4 °C, Hct = 58.)

Answer 3

Both digital clubbing and a hematocrit of 58 indicate –

chronic hypoxia, which can lead to erythrocytosis, pulmonary hypertension, and eventually right heart failure.

Traditionally, this patient’s COPD would be classified as chronic bronchitis, which is further defined by a productive cough, recurrent pulmonary infections, and bronchial obstruction from edema and mucous secretions.

These patients are often referred to as “blue bloaters”, eventually become CO2 retainers, and may experience respiratory depression with oxygen administration.

An ABG would be helpful in identifying CO2 retention.

• Clinical Note:*
• Emphysematic patients (“pink puffers”) tend to be thin, dyspneic, and pink. They typically present with increased minute ventilation and normal arterial blood gas values (i.e. normal PaCO2).

Question 4

What cardiovascular evaluation would you require prior to surgery?

(You are performing the pre-anesthetic assessment for a 68-year-old male with small cell carcinoma of the lung, scheduled for a left pneumonectomy in 2 weeks. He complains of dyspnea on exertion and uses supplemental oxygen at night. Past medical history includes COPD, asthma, HTN, peripheral vascular disease, and a 50 pack-year smoking history. Physical exam reveals digital clubbing and moderate expiratory wheezing. Medications include HCTZ, theophylline, Advair, ASA, home oxygen, and albuterol prn. HR = 70, BP = 172/88 mmHg, SpO2 = 90%, Temp = 36.4 °C, Hct = 58.)

Answer 4

(Review ACC/AHA guidelines on cardiovascular evaluation – is this case an emergency, etc? check risk profile & risk calculator)

In addition to a thorough history and physical examination focused on cardiovascular function, I would obtain –

a recent ECG.

Assuming that the patient’s ppoFEV₁ was greater than 40%, and assuming that during my history and physical exam I did not identify any active cardiac conditions or the presence of 3 or more clinical risk factors such as ischemic heart disease, prior or compensated congestive heart failure, diabetes mellitus, renal insufficiency, or cerebral vascular disease,

I would NOT require additional cardiovascular testing for this “intermediate risk” procedure

(incidence of post-thoracotomy ischemia is 5%).

However, in the case of a ppoFEV₁ that is < 40%,

I would order a preoperative echocardiographic evaluation of his right heart function, recognizing the increased risk of right heart failure in patients with COPD.

Question 5

The ABG shows: pH 7.38, PaCO2 50, and PaO2 61 on 2 liters oxygen.

What is your interpretation?

(You are performing the pre-anesthetic assessment for a 68-year-old male with small cell carcinoma of the lung, scheduled for a left pneumonectomy in 2 weeks. He complains of dyspnea on exertion and uses supplemental oxygen at night. Past medical history includes COPD, asthma, HTN, peripheral vascular disease, and a 50 pack-year smoking history. Physical exam reveals digital clubbing and moderate expiratory wheezing. Medications include HCTZ, theophylline, Advair, ASA, home oxygen, and albuterol prn. HR = 70, BP = 172/88 mmHg, SpO2 = 90%, Temp = 36.4 °C, Hct = 58.)

Answer 5

(Note – per Dr. Gallen – why is this ABG not metabolic alkalosis? – because pH would be MORE alkalotic.)

This patient is significantly hypoxic and retaining CO2 with a resulting compensated respiratory acidosis.

This patient should have a PaO2 level of around 80 mmHg on room air, and an even higher level when on 2 liters of oxygen

[Normal arterial PaO2 on room air can be estimated by 102 - (age/3)].

Although not provided, I would expect the plasma bicarbonate to be elevated, since renal compensation typically results in an increase in plasma HCO3- of approximately 4 mEq/L for each 10 mmHg increase in PaCo2 above 40 mmHg.

Note – can’t trust HCO3- on ABG (because calculated). You CAN trust HCO3- on BMP (because measured).

Question 6

The patient’s ppoFEV₁ is 37%.

Will he tolerate a pneumonectomy postoperatively?

(You are performing the pre-anesthetic assessment for a 68-year-old male with small cell carcinoma of the lung, scheduled for a left pneumonectomy in 2 weeks. He complains of dyspnea on exertion and uses supplemental oxygen at night. Past medical history includes COPD, asthma, HTN, peripheral vascular disease, and a 50 pack-year smoking history. Physical exam reveals digital clubbing and moderate expiratory wheezing. Medications include HCTZ, theophylline, Advair, ASA, home oxygen, and albuterol prn. HR = 70, BP = 172/88 mmHg, SpO2 = 90%, Temp = 36.4 °C, Hct = 58.)

Answer 6

Additional studies would have to be performed to help in determining whether the pneumonectomy would be tolerated.

Based on his PaCO2 > 45 and ppoFEV₁ of 37%, I would consider this patient to be at increased risk of postoperative respiratory complications.

Therefore, I would attempt to more accurately identify his risk, recognizing that a pre-thoracotomy evaluation should include an assessment of each of the following:

1. respiratory mechanics,
   
   • by determining the FEV₁ and the ppoFEV₁;
2. cardio-pulmonary reserve,
   
   • by determining the VO2 max, stair climbing, or 6 minute walk test; and
3. lung parenchymal function,
   
   • by measuring the DLCO, PaO2, and/or PaCO2.
4. While split-lung function studies are utilized by some centers, the lack of proven predictive validity has led many centers to replace these studies with a combination of studies including, –
   
   • spirometry, exercise tolerance, V/Q scanning, and DLCO.

Question 7

What will be your anesthetic management goals for this case?

(You are performing the pre-anesthetic assessment for a 68-year-old male with small cell carcinoma of the lung, scheduled for a left pneumonectomy in 2 weeks. He complains of dyspnea on exertion and uses supplemental oxygen at night. Past medical history includes COPD, asthma, HTN, peripheral vascular disease, and a 50 pack-year smoking history. Physical exam reveals digital clubbing and moderate expiratory wheezing. Medications include HCTZ, theophylline, Advair, ASA, home oxygen, and albuterol prn. HR = 70, BP = 172/88 mmHg, SpO2 = 90%, Temp = 36.4 °C, Hct = 58.)

Answer 7

(per Dr. Gallen – unlikely to be asked this on orals)

Preoperatively my goals are to evaluate the nature and severity of his various medical conditions, optimize pulmonary and cardiac function, and plan for anticipated complications.

Intraoperatively, I want to maintain stable hemodynamics, provide an adequate level of anesthesia, avoid bronchospasm and aspiration, secure the airway, facilitate surgical exposure by providing one-lung ventilation, and maintain adequate ventilation/oxygenation.

Postoperatively, my goals are to maintain ventilatory support as necessary, extubate as soon as possible, provide adequate pain control, and be vigilant for life-threatening post-operative complications, such as right heart failure, cardiac arrhythmias, cardiac herniation, hemorrhage, broncho-pleural fistula, pneumothorax, respiratory failure, postpneumonectomy pulmonary edema (PPE), and renal dysfunction.