2. Anatomical review
Adult trachea is about 11-14 cm long from cricoid cartilage at
C6 and divided at T5
Trachea have 16-20 cartilage joined posteriorly by fibroelastic
tissue & trachealis muscle.
Mainstem bronchus are circular, right main bronchus is wider &
shorter than the left , it gives off its upper lobe bronchus at 2.5
cm as opposed to 5 cm on the left.
Right main bronchus arises at 25 degree to vertical compared
with 45 degree on the left.
8. Ventilation and Perfution
A wake patient
the dependent lung is better perfused than the upper lung
because of a gravity.
the ventilation of dependent lung is also better as
contraction of dependent diaphragm is more efficient
and is pushed higher than the upper during expiration by
the weight of abdominal content.
the dependent lung is more favourable part of compliant
curve.
10. In a controlled ventilation
decrease in FRC with induction of anaesthesia move the upper
lung into more favourable part of compliance curve .
Upper lung is ventilated more than dependent
V/Q mismatching occur because the dependent lung continue to
have a greater perfusion and use of muscle relaxant lead to
abdominal content to rise up a gainst the dependent lung and
imped ventilation.
13. when the chest open on one side , the negative
pleural pressure lost and the lung will collapse.
Spontaneous ventilation with open pneumothorax in
the lateral position results in paradoxical
respiration & mediastinal shift
Downward shift of mediastinum during inspiration &
upward shift during expiration that causes decrease
in tidal volume.
All these changes can be overcome by positive
pressure ventilation with double lumen endotracheal
tube.
14.
15.
16. Pulmonary function test associated increase
perioperative mortality in thoracic surgery
PFT THORACOTOMY
LOBECTOMY/PNEUMONECTOMY
FVC <70% <50% OR <2L
FEVI <1L <1/2L
FEV1/FVC <50% <50%
FEF25-75 <50%
Paco2 >45-55mmhg >45-55mmhg
17. The major challenges in anesthesia for
thoracic surgery are establishing:
1. Adequate separation of the lungs.
2. Maintaining gas exchange.
3. Ensuring circulatory stability during
one-lung anesthesia.
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18. One-lung anesthesia involves lung
separation and deliberate ventilation of the
dependent lung by isolating its bronchus
from that of the nondependent lung (the
operative site) with specially designed
endotracheal tubes.
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19. Preoperative evaluation and
preparation
Patients undergoing thoracic surgery are at high risk for
postoperative pulmonary complications, particularly if
coexisting chronic pulmonary disease is present.
Risk factors associated with increased perioperative
morbidity and mortality include:
The extent of lung resection (pneumonectomy>
lobectomy> wedge resection),
Age older than 70 years,
Inexperience of the operating surgeon
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20. DISCONTINUATION OF SMOKING
Smoking
Increases airway irritability.
Increases secretions.
Decreases mucociliary transport.
Increases the incidence of postoperative pulmonary
complications.
Cessation of smoking for 12 to 24 hours before surgery
decreases the level of carboxyhemoglobin, shifts the
oxyhemoglobin dissociation curve to the right, and increases
the oxygen available to tissues.
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21. In contrast to these short-term effects improvement in
mucociliary transport and small airway function and
decreases in sputum production require prolonged
abstinence (8 to 12 weeks) from smoking.
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.
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22.
23. Management of Anesthesia
The five goals of anesthesia in thoracic surgery are to
(1) produce controlled levels of narcosis and analgesia,
(2) suppress cough and reflex airway activity,
(3) Minimize interference with protective reflexes such as
hypoxic pulmonary vasoconstriction,
(4) maintain satisfactory blood gas exchange and
cardiovascular stability,
(5) permit rapid recovery from anesthesia to avoid
postoperative respiratory depression.
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24. Induction and Maintenance
• GA with controlled ventilation with thoracic epidural analgesia
• IV induction with propofol or thiopentone
• Propofol : preferred since many of these patients will have reactive airways and use of
thiopentone and tracheal instrumentation in light plane can lead to bronchospasm
• NDMR can be used
• Maintenance : halogenated agent + opiod
• Delivered in an oxygen/air or oxygen/nitrous oxide mix
• Depression of airway reflexes and rapid elimination allowing for
rapid recovery are important benefits of volatile anesthetics
• During one-lung ventilation, anaesthesia can be maintained intravenously with propofol
and an air/oxygen mix
25. Separation of the Lungs (One-Lung
Anesthesia)
. Separation of the lungs permits intraoperative one-lung
ventilation, which greatly facilitates the surgical procedure.
1. Double-lumen endobronchial tubes (DLTs)
2. bronchial blockers (BBs) with single lumen
endotracheal tubes enable anatomic isolation of the
lungs and facilitate lung separation.
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BBs
DLTs
26. LEFT-SIDED DOUBLE-LUMEN
TUBE
Placement of a left-sided DLT
is the most reliable
widely used approach for endobronchial intubation in
one-lung ventilation .
Several manufacturers such as Mallinckrodt, Rusch, and Sheridan
produce clear, disposable polyvinyl chloride tubes with high-volume,
low pressure tracheal and bronchial cuffs.
In general, a 35- or 37-French tube can be used for most women
and a 39-French tube for most men.
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28. Insertion Technique for Placement of a Left-Sided
Double-Lumen Tube
1. Endobronchial intubation is usually accomplished by direct
laryngoscopy after induction of general anesthesia and
neuromuscular blockade.
2. The left-sided DLT tube is held so that the distal curve faces
anteriorly while the proximal curve is to the right.
3. The bronchial cuff is inserted through the vocal cords, and the
stylet is removed.
4. Next, the tube is rotated 90 degrees to the left (directing the
bronchial lumen to the left main stem bronchus).
5. The tube is advanced until moderate resistance to further
passage is encountered.
Force should never be used during advancement of the tube;
resistance usually indicates impingemen within the main stem
bronchus. An estimate of the appropriate depth of placement
of the DLT can be based on the patient's height.
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29. The average depth of insertion referenced to
the corner of the mouth is 29 cm for patients
170 cm tall, and for each 10-cm increase or
decrease in height, the average depth of
placement correspondingly changes by 1 cm.
Correct DLT position must be confirmed by
fiberoptic bronchoscopy .
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31. Fiberoptic Visualization of a Left-Sided
Double-Lumen Tube
A 3.6-mm fiberscope is initially passed through the tracheal lumen.
Correct position of the DLT is confirmed by visualization of the
carina, a nonobstructed view of the right main stem bronchus, and
the blue bronchial cuff below the carina
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34. RIGHT-SIDED DOUBLE-LUMEN TUBE
The short and variable distance of the right upper lobe orifice from
the carina makes the use of a right-sided DLT undesirable for most
procedures requiring lung separation.
A small change in the position of the tube
results in inadequate lung separation or collapse of the right upper
lobe, or both.
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36. Confirmation of correct right-sided DLT position
by physical examination alone results in a 90%
chance of malposition, with most being too
deep.
Proper positioning of a right-sided DLT must
include fiberoptic guidance.
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38. Approaches to Improve Oxygenation during
One-Lung Ventilation
Proper positioning of the DLT should be confirmed with the fiberscope
because dislodgment of the tube is may be occur after positioning of the
patient for surgery and again after surgical manipulation.
The most effective approach is the application of 5 to 10 cm H20 PEE
(CPAP) to the nondependent lung.
If the improvement in Pao2 is not sustained, selective application of PEEP to
the dependent lung is then initiated.
In many circumstances, PEEP applied to the dependent lung may result in
decreased Pao2 because of the increased PVR of the dependent lung,
which then diverts blood flow to the nondependent (atelectatic lung).
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39. The respiratory rate (R.R) is adjusted to maintain minute
ventilation at the same level as during two-lung ventilation;
Paco2 will be maintained at similar or slightly lower levels
than those observed during two-lung ventilation
In approximately 25% of patients, Pa02 is ≤80 mm Hg, and
in 10% of patients, ≤60 mm Hg.
The dependent lung should be ventilated with tidal volumes
of 8 to 10 mL/kg. Ventilation with tidal volumes of 5 to 7
mL/kg may promote atelectasis in the dependent lung.
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40. What is management of hypoxemia during
one lung ventilation?
For sudden or severe desaturation:
– Convert to two-lung ventilation
• For gradual desaturation:
1. Increase FiO2 to 1.0
2. The position of DLT should be rechecked using a
fiberoptic bronchoscope.
3. The hemodynamic status of the patient should be optimized
4. Recruitment of the ventilated lung
5. PEEP of 5-10 cm H2O: the dependent lung
6. CPAP of 1-2 cm H2O: to the nondependent lung, after a recruitment
maneuver
7. Intermittent two-lung ventilation.
8. Partial ventilation of the non-ventilated lung using either low flow
oxygen insufflations or high frequency ventilation
41. Fluid management
• Fluid restriction is generally advocated in lung resections.
• The reasons for this are:
– Third spacing is not excessive in lung surgeries
– The dependent lung : high capillary hydrostatic pressures
– Postoperative pulmonary edema
– Surgery may impair lymphatic drainage. It is
recommended that the total positive fluid balance in the
first 24 hours should not exceed 20 mL/kg
42. CONCLUSION OF SURGERY
Hyperinflation of the lungs is an important maneuver to
remove air from the pleural space at the end of thoracic
surgery .
Furthermore, alveoli incised during segmental resection
of the lungs continue to leak air into the pleural space,
thus necessitating placement of chest tubes to minimize
the air leak and promote continued expansion of the
lung.
If mechanical ventilation of the lungs must be continued
into the postoperative period, it will be necessary to
replace the DLT with a single-lumen tube.
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43. POSTOPERATIVE PULMONARY
COMPLICATIONS
atelectasis, followed by pneumonia and arterial
hypoxemia.
The severity of these complications parallels the
magnitude of decrease in vital capacity and functional
residual capacity.
Decreases in these lung volumes interfere with the
generation of an effective cough, as well as contribute to
atelectasis.
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44. Pain Management
Pain decreases respiratory effort, which results in
atelectasis, contributes to development of the stress
response with increased sympathetic nervous system
activity, and increases cardiac morbidity.
Thoracic epidural analgesia offers a unique opportunity
to improve postoperative recovery after thoracotomy.
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