-agonists are important distinguishing features of asthma. Elastase deficiency

in the airways is a feature of emphysema.

2. A. Response to a bronchodilator drug resulting in relief of airway obstruction is

highly suggestive of bronchial asthma. A more than 12% increase in predicted FEV1

and an absolute increase in FEV1 of more than 0.2 L suggest acute bronchodilator

responsiveness and variability in airflow obstruction. The reversibility of this

magnitude is almost always indicative of bronchial asthma. COPD patients do

respond to bronchodilators but not to the same extent. Early stages of asthma are

diagnosed by decreased mid expiratory flow rates (effort independent) and decreased

FEV1 and by its reversibility.

3. A. In a severely asthmatic patient, regional anesthesia is superior to general

anesthesia with an LMA, which is better than general anesthesia with ETT. The

choice of anesthetic technique is often influenced by the severity of asthma, history

of previous intubations for asthma, dependence on inhaled bronchodilators, and

patient preference. The goal in any such circumstance is to decrease airway

manipulation and stimulation. If a general anesthetic technique is pursued, inhaled

bronchodilator therapy immediately prior to induction, use of non–histaminereleasing drugs, airway manipulation only after deep anesthetic plane, and use of

intravenous lidocaine prior to intubation have all been proven to be useful.

4. B. History and physical examination can suggest presence of severe asthma if the

patient has had repeated intubations for asthma. Even though high-pitched, musical

wheezes are characteristic of asthma, they are not specific and they have no

correlation with the severity of obstruction. Spirometry is the only objective method

to quantify the severity of obstruction. Sudden severe bronchospasm can present as

high airway pressures with absence of breath sounds and very high resistance to

mechanical ventilation. Mechanical causes of obstruction such as a kinked

endotracheal tube or a mucous plug can also present a similar clinical picture and are

more common. If bronchospasm is suspected, anesthesia should be augmented with

an intravenous anesthetic such as propofol. General anesthesia through a LMA is less

stimulating to the airway than through an endotracheal tube. Volatile anesthetics are

potent bronchodilators, and they act through catecholamine-independent mechanisms.

They are rarely used as second-line agents in cases of bronchospasm refractory to

medical therapy.

5. C. Acute bronchospasm causes expiratory wheezing, increased peak inspiratory

pressure or decreased tidal volume (depending on the mode of ventilation), and a

characteristic upslope of the capnogram. Any airway stimulation can cause severe

reflex bronchoconstriction and bronchospasm in severely asthmatic patients with

hyperactive airways. Mechanical causes of obstruction such as a kinked

endotracheal tube or a mucous plug can also present a similar clinical picture and are

more common. When troubleshooting such a scenario, an intravenous anesthetic

agent is very helpful to deepen the plane of anesthesia as the delivery of inhaled

anesthetic agents may not be effective.

6. B. A patient who has adequate return of neuromuscular function and has a regular

spontaneous breathing pattern with adequate tidal volumes can be considered a

candidate for deep extubation. After clearing out the secretions from the oropharynx

and the endotracheal tube, extubation is performed under a deep plane of anesthesia

and ventilation continued by a mask/LMA. Careful patient selection is very

important, and it should not be considered in those at increased risk for aspiration of

gastric content and if the necessary airway management skills are not immediately

available. When extubation is delayed for reasons of patient safety, (presence of

gastric contents in a case with acute appendicitis), intravenous administration of

lidocaine (1.5–2 mg/kg bolus) may decrease the likelihood of airway irritation and

bronchospasm. Thus, extubation can be performed after the patient is awake and

following commands if airway irritation can be avoided.

7. C. Balanced anesthesia using an inhaled anesthetic and opioid is a safe choice for

anesthesia for a COPD patient. Use of nitrous oxide (N2O) is normally safe but not

strictly necessary. The ability of N2O to diffuse into closed air spaces may lead to

the enlargement of an emphysematous bulla or a pneumothorax and possibly rupture.

Air trapping and development of auto positive end–expiratory pressure can be

decreased by providing a prolonged expiratory time. This can be done by using a

normal tidal volume and a slow respiratory rate and an I:E ratio of ≥1:3. Care should

be taken to avoid hyperventilation and creation of a respiratory alkalosis as these

patients tolerate marked hypercapnia secondary to hypoventilation. However, high

PaCO2

levels will increase pulmonary artery pressure, which may be poorly tolerated

in patients with a compromised right-ventricular function and cor pulmonale.

Bronchodilation using inhaled β2

-agonists and pulmonary toilet through blind

suctioning or fiberoptic bronchoscopy may facilitate safe extubation of the trachea.

8. B. Pulmonary hypertension is defined as an increase in mean pulmonary artery

pressure above 25 mm Hg at rest or 30 mm Hg with exercise in the presence or

absence of an elevated pulmonary capillary wedge pressure. Right-sided heart

catheterization is the gold standard for diagnosing and quantifying the degree of

pulmonary hypertension. Care should be taken to avoid all the factors that increase

pulmonary vascular resistance in a patient with severe pulmonary hypertension

presenting for surgery. This includes avoiding hypoxia, hypercarbia, hypothermia,

light anesthesia, pain, dysrhythmias, and maintaining adequate cardiac output.

Progressive right-ventricular dilation and hypertrophy in response to an increased

afterload generated by chronic pulmonary hypertension will eventually lead to rightventricular systolic dysfunction, inadequate left-ventricular filling, and eventually

biventricular failure. The interventricular septal bulge decreases left-ventricular

cavity filling, further worsening the left-ventricular failure. Cardiac output from a

failing right ventricle depends on the filling pressure from venous return and

pulmonary pressure. Pulmonary hypertension in pregnant patients has a high mortality

rate up to 50% for vaginal delivery and even higher for cesarean delivery.

9. C. Snoring, daytime sleepiness, hypertension, obesity, and a family history of OSA

are risk factors for OSA. There is a high risk for OSA if >3 yes to the below

questions.

S (snore) Have you been told that you snore?

T (tired) Are you often tired during the day?

O (obstruction) Do you know if you stop breathing or has anyone witnessed you

stop breathing while you are asleep?

P (pressure) Do you have high blood pressure or on medication to control high

blood pressure?

B (BMI) Is your body mass index greater than 28?

A (age) Are you 50 years old or older?

N (neck) Are you a male with a neck circumference greater than 17 inches, or a

female with a neck circumference greater than 16 inches.

G (gender) Are you a male?

10. D. The extent of lung resection (pneumonectomy > lobectomy > wedge resection),

age older than 70 years, and inexperience of the operating surgeon are risk factors

associated with increased perioperative morbidity and mortality rates. In patients

with anatomically resectable lung cancer, pulmonary function tests—ppoFEV1

, lung

perfusion scanning, and exercise testing to measure maximum oxygen consumption

(VO2max)—may predict postoperative pulmonary function and outcome.

11. A. The prethoracotomy respiratory assessment has been labeled as a three-legged

stool that incorporates assessment of respiratory mechanics, cardiopulmonary

reserve, and lung parenchymal function. The following findings are considered

favorable: respiratory mechanics assessment demonstrates ppoFEV1 >40%, MVV,

RV/TLC, and FVC; the cardiopulmonary reserve measurements show VO2 max >15

mL/kg/min, 6-minute walk test, exercise SpO2 <4%, stair climb >2 flights, and

assessment of lung parenchymal function shows ppoDLCO >40%, PaO2 >60, PaCO2

<45 mm Hg. The choices B, C, and D are the most valid tests out of the “threelegged stool.”

12. A. Any patient presenting for elective surgeries with a history of smoking should

be advised smoking cessation regardless of the time available prior to surgery.

Smoking can affect the pulmonary system in multiple ways—increase in airway

irritability and secretions, decreased mucociliary transport, and increased incidence

of postoperative pulmonary complications. Patients are more receptive toward

interventions immediately prior to surgery and this provides a good teachable

moment. Prolonged abstinence (8–12 weeks) is required to improve mucociliary

transport and small-airway function and decrease sputum production. The incidence

of postoperative pulmonary complications decreases with abstinence from cigarette

smoking for more than 8 weeks in patients undergoing coronary artery bypass

surgery, and more than 4 weeks in patients undergoing pulmonary surgery. However,

even 12 to 24 hours of cessation may be beneficial because it decreases the level of

carboxyhemoglobin and it shifts the oxyhemoglobin dissociation curve to the right.

13. B. The angle between the right main bronchus and trachea is 25 degrees at the

level of carina, but the left main bronchus takes off at an acute angle of 45 degrees.

Thus, right main bronchus is shorter, wider, and more in line with the trachea. There

is a good correlation between tracheal and bronchial width (bronchial diameter is

predicted to be 0.68 of tracheal diameter).

The right upper lobe bronchus takes off at an acute angle from the point of origin

of the right primary bronchus and is easily occluded if the ventilation port on the

right-sided DLT is not aligned properly. Because of these reasons, a left-sided DLT

is most commonly used. Uniform ventilation to all lobes can be achieved more easily

with a left-sided DLT than a right-sided one. Measurement of tracheal width from a

posteroanterior chest roentgenogram can help select the size of a left-sided DLT. In

addition to physical examination, fiberoptic assessment should be done to confirm

proper position of a left-sided DLT because the malposition incidence if confirmed

with auscultation alone is considered to be 20% to 48%.

14. C. There is no single predictor that can accurately predict the appropriate size of a

DLT. But a general guideline is a woman shorter than 160 cm should be intubated

with a 35-Fr tube, a woman taller than 160 cm should be intubated with a 37-Fr tube,

and a man shorter than 170 cm should be intubated with a 39-Fr tube, and a man

taller than 170 cm should be intubated with a 41-Fr tube. This tube size of 37 Fr may

be too big for this lady. When we inflated the bronchial cuff and attempted

ventilation, the unoccluded outflow tract of the bronchial lumen made it easy to

ventilate. However, after inflating the tracheal cuff (with the bronchial cuff already

inflated), failure to ventilate suggests that something is occluding the tracheal lumen

(the bronchial cuff in this situation). The presence of breath sounds only on the right

side with both the cuffs inflated suggests that the bronchial lumen is patent and

ventilating the right side. The ventilated gas coming out of tracheal lumen is being

trapped between the tracheal and the bronchial balloons. This finding can be

confirmed with fiberoptic bronchoscopy, and the tube needs to be repositioned with

bronchial cuff in the left main-stem bronchus. If with the same clinical picture, you

are hearing breath sounds only on the left side with both the cuffs inflated, it could be

that the DLT is too far into the left bronchus with the tracheal lumen opening into the

left main stem. It is also possible that the bronchial cuff is barely into the left main

stem with a herniated bronchial cuff preventing the inflation of right-sided lung via

the tracheal lumen.

Figure 12-3.

15. B. Figure 12-4A is a bronchial blocker for a left-sided lung surgery placed deeply

into the left main-stem bronchus. Figure 12-4B is a bronchial blocker advanced too

far into the right main stem, and the balloon of the bronchial blocker is occluding the

right upper lobe takeoff. For both situations, the bronchial blocker should be

withdrawn a couple of centimeters to a level just below the carina.

Figure 12-4.

Figure 12-4.

16. B. Difficulties with oxygenation are fairly common during one-lung ventilation. If

the SpO2

is below acceptable range, various techniques that can be tried to improve

the oxygenation include increasing FIO2

to 1, intermittent two-lung ventilation,

applying positive end–expiratory pressure (PEEP) to the dependent lung. However,

the most effective method is the application of 5 to 10 cm H2O CPAP to the

nondependent lung. This should be done prior to application of PEEP to the

dependent lung. This low level of CPAP results in minimal lung inflation and

generally does not interfere with surgery. A slow inflation of 2 L/min of oxygen into

the nonventilated lung for 2 seconds and repeated every 10 seconds for 5 minutes or

until the saturation rises to 98% has been shown to improve oxygenation during onelung ventilation. CPAP applied to the operative lung may be disadvantageous in

some cases like thoracoscopy, bronchopleural fistula, sleeve resection, or massive

pulmonary hemorrhage.

17. D. During spontaneous ventilation in lateral decubitus position,

ventilation/perfusion matching is preserved because the lower lung receives more

perfusion due to gravity and more ventilation due to better contraction of the

dependent hemidiaphragm. The dependent hemidiaphragm gets a better displacement

from a higher position in the chest. The dependent lung has a better compliance as

well—this improves ventilation.

Figure 12-5.

18. A. Inspiration in a lateral position during spontaneous ventilation causes more

negative pleural pressure on the dependent side of the open pneumothorax. The

relatively higher pressure on the nondependent side causes a downward shift of the

mediastinum during inspiration. The reverse happens on expiration, and the

mediastinum shifts upward. This results in an ineffective respiratory exchange, but

the major effect is by decreasing the contribution of the dependent lung to the tidal

volume.

Figure 12-6.

19. C. HPV is a protective mechanism by which body shunts away blood from a

nonventilated lung. It plays a significant role in maintaining oxygenation during onelung ventilation. Factors inhibiting HPV include infection, pulmonary

hyper/hypotension, low PaCO2

, changes in SvO2

(mixed venous oxygen saturation),

and pharmacological agents like vasodilators—nitroglycerin and nitroprusside, βagonists, calcium channel blockers, and inhalational anesthetic agents.

20. C. Left-sided DLTs are most commonly used in clinical practice. Any change in

position of the patient after the DLTs have been placed includes a risk of

malpositioning of the DLT. Low exhaled tidal volumes and poor lung compliance are

the most common initial indicators. Left-sided DLT may be malpositioned back into

the trachea, into the right main-stem bronchus, or too far into the left primary

bronchus. If it is in the trachea, the inflated bronchial cuff is preventing any ventilated

gas from going past it. If it is in the right side or pushed too far into the left bronchus,

the bronchial cuff may be obstructing the left upper or left lower lobe bronchus.

These two situations can be immediately relieved by deflating the bronchial cuff.

21. D. DLTs are considered to be the best lung isolation device currently in use. In

certain situations, placement of a DLT is difficult and bronchial blockers are used for

lung isolation. They are similar to Fogarty catheters and are single-lumen devices

with an inflatable balloon at the tip. They are passed through a single-lumen

endotracheal tube under fiberoptic guidance and the balloon is inflated within the

bronchus of the operative side. The cuff of the bronchial blocker is a high-pressure–

low-volume cuff. The single narrow lumen within the blocker allows the lung to

deflate (though slowly) and can be used for suctioning or insufflating oxygen (below).

The biggest problem is caused by the small size of the channel, which impairs

exhalation. However, in patients with a history of difficult intubation bronchial

blockers circumvent the need to reintubate a patient prior to transferring out of the

operating room.

22. C. The mortality rate for pneumonectomy is about 5% to 7%, compared with 2%

to 3% for a lobectomy. Mortality is higher for right-sided pneumonectomy than for

left-sided pneumonectomy. This is attributed to the greater loss of lung tissue. Lung

cancer resection surgeries involve finding the right balance between resecting enough

lung tissue to obtain a tumor-free margin, at the same time leaving enough for

residual postoperative pulmonary function. Wedge resections for peripheral lesions,

lobectomy for bigger tumors, pneumonectomy for tumors involving the main

bronchus, sleeve resections for patients with proximal lesions, and limited pulmonary

reserve are among the various choices the surgeons can make.

23. C. The incidence of arrhythmias increases with age and with the amount of

pulmonary resection. Perioperative arrhythmias are fairly common after thoracic

surgery—atrial fibrillations/SVTs and PVCs are all seen and are thought to be a

result of the surgical manipulation of the heart and distension of the right atrium as a

result of decreased pulmonary vascular bed. Pulmonary complications after surgery

can be decreased by preoperative incentive spirometry, bronchodilator therapy, and

good pulmonary hygiene.

24. B. Halogenated agents generally have minimal effects on HPV in doses <1

minimum alveolar concentration (MAC). Balanced anesthetic technique using a

combination of inhaled anesthetic agents and intravenous opioids is beneficial.

Inhalational agents allow delivery of 100% oxygen, are potent bronchodilators, and

can be easily titrated to desired concentration and opioids have minimal

hemodynamic effects as well as providing analgesia. They complement each other

very well. However, use of long-acting opioids should be limited during surgery to

prevent excessive postoperative respiratory depression. The only choice with

<1MAC is B.

25. D. Anesthetic management of pulmonary resections includes very tight fluid

management. Most of the time restrictive fluid management strategy facilitated by

use of blood/colloids is entertained. Lower lung syndrome refers to gravitydependent transudation of fluid into the dependent lung, which decreases effective

oxygenation, increases ventilation–perfusion mismatch, shunting, and promotes

hypoxemia. This transudation is worsened by excessive administration of intravenous

crystalloids. On the nondependent side, reexpansion of the collapsed lung can result

in pulmonary edema due to alteration in the pressures on either side of the Starling

equation.

26. A. Hypoxemia is fairly common after institution of one-lung ventilation in the

lateral position. Various interventions can be tried when it happens—some have

better efficacy than the others. These include periodic reinflation of the collapsed

lung with oxygen, which interferes with surgery; early ligation or clamping of the

ipsilateral pulmonary artery—seldom used but can be tried in pneumonectomies; and

CPAP (5–10 cm H2O) to the collapsed lung causing partial reexpansion of the lung

and may interfere with surgery. The mechanism of action of CPAP application is

supposed to oxygenation as well as displacement of blood from the pulmonary

vasculature into the dependent lung. Other less efficacious methods that can be tried

include PEEP (5–10 cm H2O) to the ventilated lung, oxygen insufflation to collapsed

lung (diffusion respiration), and change in dependent lung minute ventilation (Vt 5

mL/kg is usually recommended but can be increased). Application of CPAP to the

collapsed lung should be done before instituting PEEP to the ventilated lung, as the

effect of PEEP depends on where the lung falls on the PEEP–PVR curve. Persistent

hypoxemia requires immediate return to two-lung ventilation.

27. D. Apneic oxygenation refers to insufflation of 100% oxygen at a rate greater than

the oxygen consumption (>250 mL/min) while the ventilation is stopped. Progressive

respiratory acidosis limits the use of this technique to 10 to 20 minutes in most

patients. Oxygenation can be maintained in patients with normal DLCO for more than

this time interval. During apneic oxygenation, arterial PCO2

rises 6 mm Hg in the first

minute followed by 3 to 4 mm Hg every subsequent minute.

28. A. Bronchopleural fistula refers to a communication between the bronchial and

pleural spaces. It presents as a sudden large air leak from the chest tube that may be

associated with an increasing pneumothorax and partial lung collapse. Inadequate

surgical closure of the bronchial stump usually presents itself with a bronchopleural

fistula in the first 24 to 72 hours. Necrosis of the suture line (bronchial/parenchymal)

caused by ischemia or infection usually presents after 72 hours. This is a rare

complication, but small air leaks are fairly common after segmental or lobar

resection due to collateral ventilation from small channels at the sites of incomplete

fissures. They are usually smaller in volume, will not cause significant impairment of

ventilation, and will close by itself after a few days—after which chest tubes can be

discontinued.

29. C. This is the classical picture of torsion of a lung lobe as it expands to fill up the

space left by resection of the other lobe. This is because the torsion results in

occlusion of the pulmonary vein, which drains blood flow to that part of the lung and

presents clinically as hemoptysis and radiographically as an enlarging homogenous

density. This can be confirmed by visualizing a closed lobar orifice on

bronchoscopy. On the other hand, an acute herniation of the heart into the operative

hemithorax is associated with hemodynamic changes and a shift in the cardiac

shadow on chest X-ray. This is caused by a large pressure difference between the

two hemithoraces. Herniation to the right causes severe hypotension and an elevated

central venous pressure due to torsion of the vena cava. Herniation to the left causes

compression of the heart at the atrioventricular groove, resulting in hypotension,

ischemia, and infarction.

30. D. With the given history, the massive hemoptysis (defined as >500–600 mL of

blood loss in 24 hours) is most likely infectious in origin with tuberculosis being a

strong possibility. The other causes of massive hemoptysis include bronchiectasis,

aspergillomas, neoplasms, foreign body in the trachea, and trauma. A potentially

lethal hemoptysis with severe hemodynamic compromise necessitates emergency

surgery. Bronchial artery embolization may be attempted if the patient is

hemodynamically stable. Whenever possible, surgery is carried out in a semi-elective

way, but the operative mortality is still high, >20%. However, medical management

is associated with a much higher mortality, >50%. The most common cause of death

is asphyxia secondary to blood in the airway.

31. C. Pulmonary cysts or bullae are large cavitary lesions that behave as if they have

a one-way valve, gets progressively large and may compress the remaining lung

tissue. They may also rupture producing a tension pneumothorax. They can be

congenital or acquired as a result of emphysema. They are usually scheduled for

lung resection surgeries when they cause recurrent pneumothorax or progressive

dyspnea. Positive-pressure ventilation results in further expansion of such cavities

and increased risk of rupture along with impaired oxygenation from the affected lung.

Maintenance of spontaneous ventilation (negative inspiratory pressure) is

recommended until the affected lung is isolated using a DLT or until a chest tune is

placed. Inhalational agents can be used to facilitate this, but the large dead space

caused by the presence of huge cyst may result in progressive hypercarbia. Assisted

ventilation is helpful in such circumstances. Care should be taken to avoid complete

positive-pressure ventilation.

32. C. Tracheal stenosis is narrowing of the airway as a result of tracheal mucosal

damage followed by scarring. It can also be caused by tumors—squamous or

adenoid cystic carcinoma. The inciting factors for the mucosal damage include

trauma or prolonged endotracheal intubation. These patients present with progressive

dyspnea, hemoptysis, and stridor on exertion. The dyspnea is characteristically worse

on lying down and is made better by sitting up and leaning forward.

33. A. Anesthetic considerations for tracheal resection include invasive monitoring,

use of anticholinergics to prevent increased secretions, slow inhalational induction

maintaining spontaneous ventilation, airway stimulation after attaining a deep plane

of anesthesia, return of spontaneous ventilation, and early extubation. The left radial

artery is preferred for lower tracheal resections because of the potential for

compression of the innominate artery. A nonirritating inhalational agent like

sevoflurane in 100% oxygen can be used along with short-acting opioids like

remifentanil. Care should be taken to decrease the FIO2

to below 0.3 if the surgeon is

using laser to resect the scar tissue. After opening the stenosed segment, the surgeon

can insert a sterile endotracheal tube into the segment of trachea below the lesion and

patient can be ventilated through that. There will be a brief period of apnea as the

surgeon is anastomosing the anterior part of trachea after resection. Once the

anastomosis is complete, the initial endotracheal tube can be readvanced below the

lesion. The neck is kept flexed in the postoperative period to minimize tension on the

tracheal suture line. Heliox offers a method to avoid turbulence due to its lower

density. Flow–volume loops confirm the location of the obstruction and aid the

clinician in evaluating the severity of the lesion.

Figure 12-7.

34. D. Mediastinoscopy involves operating on an area covered with blood vessels and

nerves. The complications include reflex bradycardia due to vagal stimulation,

bleeding from damage to the great vessels, pneumothorax, air embolism, post-op

hoarseness due to recurrent laryngeal nerve injury, and phrenic nerve injury. A false

drop in blood pressure may be observed due to compression of the innominate artery

if the arterial line is placed on the right arm. A spontaneously breathing patient with

head end elevated is also at risk for a pneumothorax that presents postoperatively.

35. D. Pulmonary alveolar proteinosis is a condition in which patients produce

excessive quantities of surfactant and fail to clear it, producing bilateral lung

involvement and recurrent pneumonias. Bronchoalveolar lavage is performed in these

patients for severe hypoxemia or worsening dyspnea. They undergo sequential lung

lavages interspaced by a few days with the worse lung getting lavage first. It is an

absolute indication for lung isolation. If both lungs are lavaged during the same

procedure, it significantly impairs effective oxygenation.

Lung isolation for unilateral bronchoalveolar lavage is obtained by a double-lumen

tube under general anesthesia. Proper positioning of the tube by bronchoscopy is

essential prior to the lavage to prevent contamination of the opposite lung. A watertight seal with the cuffs is also essential prior to the lavage. The procedure is

normally done in the supine position; lavaging a dependent lung in a lateral position

helps to minimize soiling of the nondependent lung, but the ventilation–perfusion

mismatch caused by ventilating a nondependent lung which is not perfused is severe

and makes this clinically impossible. Warm normal saline is infused into the lung to

be treated and is drained by gravity; treatment continues until the fluid returning is

clear (about 10–20 L). Patient can be extubated after carefully suctioning out both

the lungs or the double-lumen tube is replaced by a single-lumen tube at the end of

the procedure.

36. B. Right-ventricular failure caused by increase in right-sided afterload (increased

pulmonary artery resistance) may recover after isolated lung transplantation, and they

do not require combined heart–lung transplantation. Such is not the case in patients

with Eisenmenger syndrome who require combined heart–lung transplantation.

However, normal left-ventricular function and absence of significant coronary artery

disease or other serious health problems is ensured before lung transplantation, as the

wait list of patients for the organs are long. Respiratory failure caused by cystic

fibrosis, bullous emphysema, or vascular diseases are usually bilateral and

necessitate a double-lung transplant. It can be done using cardiopulmonary bypass or

sequentially using one-lung ventilation depending on the pulmonary artery pressures

and the ventricular function. Single-lung transplantation is being increasingly

performed for patients with chronic obstructive pulmonary disease. Organ selection

is based on size, ABO compatibility, and cytomegalovirus serology matching.

37. A. A newly transplanted lung lacks the neural innervation, lymphatic drainage, and

bronchial circulation, which were present in the explanted lung. Central respiratory

pattern generated by centers in the brain stem is unaffected. Hypoxic pulmonary

vasoconstriction, mediated locally is also unaffected. However, loss of lymphatic

drainage increases extravascular lung water and predisposes the transplanted lung to

pulmonary edema. Fluid restriction is fairly common after lung transplantation to

prevent this from happening. Although some patients develop bronchial

hyperreactivity, cough reflex is abolished below the carina. These patients usually

get postoperative bronchoscopy to assess bronchial suture line, as they are prone for

ischemic breakdown in the absence of bronchial circulation.