Fob in icu. current practice

By
Mahmoud E. Abolmagd
Assistant lecturer of pulmonary and critical
care medicine
FOB IN ICU
CURRENT PRACTICE

INTRODUCTION
FOB IN ICU 3
• The critical patient often has one or more organ failures, which
makes him or her a high-risk patient for the procedure.
• The bronchoscopist is faced with a reduced amount of space,
because of crowding of the monitoring equipment and
therapeutic devices.

INTRODUCTION
FOB IN ICU 4
• 45% were performed for the removal of retained bronchial
secretions.
• 35% for collecting samples from the lower respiratory tract.
• 7% for assessing the airway.
• 2% for hemoptysis.
• 0.5% for assisting tracheal intubation.
• 0.5% for the removal of foreign bodies.

DIAGNOSTIC INDICATIONS
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- - Pneumonia
-
- Hemoptysis
-
- Thoracic trauma
-
- Inhalation airway injury

PNEUMONIA
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• nosocomial pneumonias occur in 9% to 25% of patients
on mechanical ventilation.
• ventilator-associated pneumonia (VAP) has a mortality
rate of 35% to 90%.
• The role of bronchoscopy in patients with suspected
pneumonia is to identify the infectious agent, thereby
allowing one to narrow the antibiotic spectrum; it also
avoids treating patients without infection,

PNEUMONIA
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• FOB is particularly useful in immunocompromised
patients with pulmonary infiltrates, as it is a technique
with a high diagnostic yield in these patients, especially
in the identification of PCP, TB , and fungi.

PNEUMONIA
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• bronchoalveolar lavage (BAL) and protected specimen brush
(PSB) .
• Transbronchial lung biopsy (TBLB) is a risky procedure in
patients under mechanical ventilation.
• in lung transplant recipients, it is invaluable in establishing the
differential diagnosis between infection and graft rejection.

PNEUMONIA
FOB IN ICU 11
• The technique of BAL fluid collection implies wedging of the tip of
the flexible bronchoscope into an airway lumen, isolating that
airway from the rest of the bronchial tree. Then, at least 120 mL
of isotonic saline is instilled in several aliquots (3 to 6) through
the working channel of the bronchoscope, and gentle hand
suction is applied to retrieve the fluid.

PNEUMONIA
FOB IN ICU 12
• The amount of fluid returned,
usually 40% to 70%. a very small
return may result in false
negative results).
• No more than 30 minutes should
elapse between BAL collection
and processing for
microbiological analysis.

PNEUMONIA
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• The methodology for PSB
implies the use of a double-
lumen catheter brush system
with a distal occluding plug to
prevent contamination from
airway secretions during the
passage of the
catheter through the flexible
bronchoscope channel.
• As for BAL, rapid processing of
the samples is desirable .

PNEUMONIA
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• In the case of BAL fluid, the diagnostic threshold for infection is
104 CFU/mL.
• For PSB samples, the proposed cutoff is 103 CFU/ mL.
• The sensitivity of BAL ranges from 60% to 90% for bacterial
infections; 80% for mycobacterial, fungal, and most viral
infections; and 95% for PCP.

PNEUMONIA
FOB IN ICU 15
• false-positive results by upper airway contamination must be
minimized by using an aseptic technique and avoiding tracheal
and main bronchi aspiration.
• the use of lidocaine should be restricted, as it can inhibit bacterial
growth.
• If the patient is already under antibiotic coverage, the diagnostic
yield of BAL and PSB will be very low .

HEMOPTYSIS
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• allows the identification of the site of bleeding and the guidance
of subsequent therapeutic interventions. If the source of bleeding
is not visible, segmental lavages can be performed in search of
fresh blood in recovered fluid.
• The approach of mild to moderate hemoptysis requires the
instillation of cold saline, epinephrine, and fibrin precursors.

HEMOPTYSIS
FOB IN ICU 18
• it is not clear whether it is
preferable to use the rigid
bronchoscope or the flexible
bronchoscope.
• allowing control of the airway:
proper ventilation during the
procedure, better visualization,
and effective aspiration of blood
clots.

HEMOPTYSIS
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• The flexible bronchoscope despite
providing access to more distal
areas of the bronchial tree, has a
limited suction capacity, but
allows some basic procedures for
airway maintenance and
immediate control of the bleeding.
In addition, a cryoprobe can be
used to remove large clots from
the airway.

HEMOPTYSIS
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• After locating the source of hemoptysis,
a 200-cm-long Fogarty balloon-tipped
catheter can be introduced through the
flexible bronchoscope working channel
to tamponade the bleeding bronchial
subsegment.
• This is achieved by inflating the balloon
to occlude the bleeding zone. The
balloon is deflated after 24 to 48 hours.

HEMOPTYSIS
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• In cases of unilateral massive
bleeding, selective endobronchial
intubation of the nonbleeding
lung can be a life-saving
measure.

HEMOPTYSIS
FOB IN ICU 22
• If an endobronchial
lesion is detected,
electrocautery,
cryosurgery, and laser
photocoagulation
through the flexible
bronchoscope are
useful therapeutic
tools .

THORACIC TRAUMA
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• Tracheobronchial lesions affect 3% of patients with severe closed
chest trauma.
• They may arise in the form of fractures or lacerations of the
tracheobronchial tree.
• fracture of ribs, clavicle, or sternum; chest wall contusion;
hemoptysis, dyspnea, and evidence of pneumothorax,
pneumomediastinum, atelectasis, or subcutaneous emphysema.

THORACIC TRAUMA
FOB IN ICU 25
• FOB is the fastest and safest way to diagnose such
injuries.
• In particular, a pneumothorax associated with a
persistent large air leak after tube thoracostomy is an
indication for urgent FOB.

THORACIC TRAUMA
FOB IN ICU 26
• The radiologic evidence of
lung collapse in the most
dependent area of the lung
field (falling lung sign) is
rare but pathognomonic of
total rupture of a mainstem
bronchus.

AIRWAY INHALATION INJURY
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• Airway inhalation injury is
common in fire victims, especially
when plastic-derived or other
synthetic material combustion
fumes are inhaled.
• It can be divided into chemical or
thermal injury,

FOB IN ICU 29
• Inhalation injury can occur in the absence of skin lesions and
may be asymptomatic during the first 72 hours, even in patients
with the most serious injuries, and this is the reason why FOB
must be performed early in suspected cases.
• The indications for performing FOB are facial or nasal burns,
suspected acute obstruction of the airway, laryngeal edema
develops quickly and can compromise the airway.

FOB IN ICU 30
• the endoscopic appearance of the mucosa can
be almost normal at an early stage, with slight
hyperemia and edema, which can go
unnoticed, especially in the absence of carbon
particles.
• Hours later, the mucosa may show scaly and
necrotic areas, with carbon particles and focal
areas of ulceration, alternating with areas of
normal mucosa, creating a “mosaic” or “leopard
skin” appearance.

THERAPEUTIC INDICATIONS
FOB IN ICU 32
- Endotracheal intubation
- Atelectasis
- Tracheobronchial obstruction (foreign body or
endoluminal lesion)

ENDOTRACHEAL INTUBATION
FOB IN ICU 34
FOB plays a key role in 3 major groups of situations in
which airway management is not simple:
• evaluation of the airways before intubation,
• intubation of the non-sedated patient,
• intubation in cases where neck extension is prohibited,

ENDOTRACHEAL INTUBATION
FOB IN ICU 35
• If oro-tracheal intubation is to be performed, it is recommended
to use a mouth guard to prevent biting of the flexible
bronchoscope.
• In adults, one should try to pass an 8.0mm inner diameter ETT.
Intubation under endoscopic control is very useful in the
placement of double-lumen tracheal tubes and also in the
intubation of patients carrying airway stents, as blind tracheal
intubation carries the risk of migration of the stent.

ATELECTASIS
FOB IN ICU 37
• 27% of emergency ICU FOB were performed because of
atelectasis and retention of secretions.
• necessary in patients with tenacious bronchial secretions, which
form thick mucus plugs that are extremely difficult to aspirate
even with flexible bronchoscope suction.
• In those circumstances, FOB should not be delayed because of
hypoxemia; respiratory failure in these patients is the clinical
indication for performing the procedure .

TRACHEOBRONCHIAL OBSTRUCTION
FOB IN ICU 39
• The removal of tracheobronchial
foreign bodies may be attempted by
FOB, using a biopsy forceps or a
Dormia basket.
• there are situations when it is
preferable to use the rigid
bronchoscope, because of the foreign
body’s size or for safety reasons (risk
of aspiration and fragmentation).

RESPIRATORY MECHANICS
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• A flexible bronchoscope with an outer diameter of 5.7 mm
occupies approximately 10% of the cross-sectional area of the
trachea .
• The immediate consequence is some degree of airway
obstruction. In a conscious, spontaneously breathing patient, the
obstruction it creates is mild to moderate, perfectly tolerated, and
does not induce significant intra-tracheal pressure variations.

FOB IN ICU 42
• in the ventilated patient, the obstructive effect of the flexible
bronchoscope is added to that of the ETT. Indeed, a 5.7 mm
flexible bronchoscope occupies 50% of 8.0-mm inner diameter
ETT, and 66% of 7.0-mm inner diameter ETT.
• This obstruction leads to a significant increase in airway
resistance, which in turn generates significant intra-tracheal
pressure variations during the respiratory cycle .

FOB IN ICU 43
• with an 8.0 mm ETT, autoPEEP usually remains below 20
cmH2O, but PEEP values of 35 cmH 2O were reported in a
patient carrying a 7.0 mm ETT, making otherwise healthy patients
prone to develop pneumomediastinum and pneumothorax.
• The auto-PEEP induces a 30% increase in FRC and 40%
decrease in FEV1 as well as a reduced VC . As a consequence,
expiratory tidal volume (VTe) is significantly reduced.

FOB IN ICU 44
• tidal volume (VT) is significantly reduced. During the inspiratory
phase of the respiratory cycle, with significant increase of peak
pressure. The resulting hypoventilation may induce significant
blood gas changes.
• Continuous and prolonged suction periods may reduce VT
leading to small airway collapse and serious V/Q mismatch,
inducing severe hypoxemia, In this sense, suction should be
quick and intermittent.

GAS EXCHANGE
FOB IN ICU 46
• The presence of the flexible bronchoscope in the airway is
associated with 10 a to 20 mm Hg reductions in PaO2 in an
uncomplicated examination.
• When suction is applied, however, PaO2 fall can be more
pronounced. Indeed, each suction can induce a 200 to 300 mL
fall in VT, which can induce a 40% decline in PaO2. If in addition,
there is some VT loss through the swivel adaptor in ventilated
patients, desaturation can be even more pronounced.

GAS EXCHANGE
FOB IN ICU 47
• Another feature contributing to the observed hypoxemia during
FOB is reflex bronchoconstriction, mediated by subepithelial
parasympathetic nervous system receptors located in the large
airways. An adequate topical anesthesia can reduce this effect.
• The performance of BAL has a known deleterious effect on
oxygenation. The PaO2 decline shortly after BAL can be
explained by 2 phenomena: epithelial surface changes induced
by the instilled fluid and local proinflammatory mediators release.
After the procedure, there is a gradual return to baseline PaO2
levels, which can take approximately 15 minutes in the normal
individual to several hours in the presence of severe pulmonary
parenchymal disease.

GAS EXCHANGE
FOB IN ICU 48
• In some patients, there may be a rise in PaO2. Such cases are
associated, almost invariably, with the resolution of atelectasis by
suction of tracheobronchial secretions or blood clots.
• Another phenomenon that may contribute to better oxygenation
is the auto-PEEP generated during the procedure, which, by
recruiting collapsed alveoli, improves ventilation-perfusion
relation

GAS EXCHANGE
FOB IN ICU 49
• With regard to changes in ventilation, a slight rise of
approximately 8.0 cm Hg in the partial pressure of carbon dioxide
in arterial blood is common during the procedure.
• This increase reflects alveolar hypoventilation induced by the
cumulative effect of the reduction in VT and lung inflation.
Prolonged periods of suction, particularly in the absence of
secretions, can exacerbate this phenomenon.

HEMODYNAMICS
FOB IN ICU 51
• The combined effects of hypoxemia, hypercapnia, mechanical
irritation of the airways, and the patient’s own anxiety (less
important feature in sedated and ventilated patients) cause
adrenergic stimulation, with consequent increase in mean arterial
pressure, heart rate, and pulmonary artery pressure, 50%
increase in cardiac output during FOB, with a return to baseline
levels 15 minutes after the procedure.

TECHNICAL ASPECTS
FOB IN ICU 53
• Anesthetize the tracheobronchial tree properly;
• Sedate the patient (add muscle relaxation);
• The ETT should have an inner diameter of at least 8.0 mm; the
difference between the inner diameter of the ETT and the outer
diameter of the flexible bronchoscope should be 2 mm. If the
patient is intubated with an ETT <8.0 mm, and tube change is not
a viable option, then a pediatric or an ultrathin bronchoscope can
be used.

TECHNICAL ASPECTS
FOB IN ICU 54
• Ventilate on volume control mode.
• Pressure-control ventilation will also result in a reduced VT,
unless the inspiratory pressure level is increased to compensate
for high airway resistance during the procedure.
• Use a swivel adapter to minimize VT loss through the circuit;

TECHNICAL ASPECTS
FOB IN ICU 55
• Set PEEP to 0 cmH 2O (if this is not feasible, reduce the PEEP
level by 50%).
• Apply suction only for short periods (3 s or less).
• During the procedure, continuous electrocardiogram, blood
pressure, and peripheral O2 saturation monitoring is mandatory.
Cardiopulmonary resuscitation equipment should always be at
hand.

TECHNICAL ASPECTS
FOB IN ICU 56
• Increase FiO 2 to 100%, starting 5 to 15 minutes before the
procedure, for adequate pre-oxygenation. Maintain FiO2 at 100%
during and up to 1 hour after FOB, with the purpose of keeping
SaO2 as close to 100% as possible;
• After the procedure, the patient should receive a chest
radiograph to exclude pneumothorax or pneumomediastinum.

SEDATION AND ANALGESIA
FOB IN ICU 58
• Sedation is used to achieve patient comfort, safety, and
cooperation.
• Most frequently, a combination of benzodiazepines and opiates is
used.
• Midazolam is the preferred benzodiazepine, given its rapid onset
of action (<5 min) and short half-life. Sedation can be prolonged
in elderly patients, and dose reduction is necessary for hepatic
failure.

FOB IN ICU 59
• Fentanyl has an onset of action of <90 s and is the preferred
analgesic in patients with hemodynamic compromise, because
cardiovascular effects are minimal.
• Respiratory depression and hypoxemia are potential adverse
effects of these drugs, and the combination of both can induce
greater hypoventilation than midazolam alone.

FOB IN ICU 60
• Propofol is an anesthetic that can also be used for sedation, either by
bolus administration or continuous infusion. Its rapid onset of action
(<1 min) and recovery time are advantageous.
• Clearance is not affected by renal or hepatic failure. However,
respiratory and cardiovascular depression are more likely to occur with
this drug, as deep sedation and general anesthesia and thus propofol
use requires some degree of experience and expertise. It is a very
good agent for sedation of mechanically ventilated patients, although it
must be managed with caution in hemodynamically unstable patients.

FOB IN ICU 61
• Ketamine elicits sedative and analgesic effects without
cardiovascular depression.
• Respiratory depression is also minimal, unless the drug is
infused too rapidly or inappropriately high doses are used.
However, its dissociative properties may induce a state of
emergence delirium, which is the reason why it must be used
with caution in adult patient sedation. Laryngospasm is another
troublesome side effect.

FOB IN ICU 62
• Thiopental is a barbiturate used for short term sedation.
Hypotension is its most prominent adverse effect, and advanced
age and critical illness potentiate this effect.
• It is not routinely used for FOB. Both propofol and thiopental are
purely sedative/amnestic drugs and must be used in association
with an analgesic drug.

COMPLICATIONS
FOB IN ICU 64
• Major complications arise in 0.08% to 0.15%, and minor
complications occur in approximately 6.5% of the cases.
• mortality rate of 0.01% to 0.04%.
• massive hemoptysis, laryngospasm, bronchospasm,
arrhythmias, pneumothorax, subcutaneous emphysema,
tracheal perforation, and airway obstruction ,
cardiorespiratory arrest, and pulmonary edema.

COMPLICATIONS
FOB IN ICU 65
• implementation of therapeutic bronchoscopic techniques, such as
electrocautery, argon-plasma coagulation, laser, balloon dilation,
and stenting, is in close relation to the increase in severe
complication rate.
• the use of lidocaine for local anesthesia may cause
laryngospasm and bronchospasm to arrhythmias, seizures,
bronchoscopists should not forget that lidocaine is a drug with documented
absorption by the airway mucosa and that its maximal dose must therefore not
be exceeded (8.0 mg/kg). Careful attention should be paid to patients with
hepatic failure, in whom lidocaine metabolism is impaired.

COMPLICATIONS
FOB IN ICU 66
• The risk for bacteremia after FOB, although it was once thought
to be very small, can be as high as 6.5%, (especially in
immunocompromised patients).
• Still, endocarditis prophylaxis is not generally recommended,
except in asplenic patients, patients with prosthetic valves, or
patients with previous endocarditis history.
• Pneumonia is a rare complication.

COMPLICATIONS
FOB IN ICU 67
• Fever after FOB is not common, although reported frequencies of
this complication range from 1% to 20%.
• It is usually self-limited, subsiding in the first 24 hours . due to
Transient bacteremia and the release of pro-inflammatory
cytokines .
• In patients undergoing BAL, fever can occur in up to 30% of
cases.

COMPLICATIONS
FOB IN ICU 68
• Arrhythmias result from the combined effects of hypoxemia and
increased sympathetic tone during the examination, with
associated tachycardia and myocardial ischemia.
• hypoxemia is the most important and should be strongly avoided
by administration of supplemental oxygen, by performing the
procedure as quickly as possible, and, if necessary, by
intermittent removal of the FOB from the patient’s airway to allow
ventilation (especially in patients under mechanical ventilation).

COMPLICATIONS
FOB IN ICU 69
• Bleeding during bronchoscopy is considered significant if it exceeds 50
mL.
• The risk of bleeding is highest with TBLB, followed by bronchial biopsy,
bronchial brushing, and finally BAL .
• The risk of TBLB-associated bleeding is up to 10% and, in most cases,
is self-limited or can be stopped with the local instillation of cold saline
or adrenaline. However, there have been situations of uncontrolled
bleeding that must be managed with endobronchial tamponade,
selective intubation of the non-bleeding lung, and, in extreme cases,
surgery.

COMPLICATIONS
FOB IN ICU 70
• Factors that increase the risk of bleeding include coagulopathies,
thrombocytopenia, platelet dysfunction, severe uremia, hepatic
failure, pulmonary hypertension (PH), superior vena cava
syndrome, and malabsorption.
• The bleeding risk is, likewise, increased in immunocompromised
patients and patients with severe malnutrition.

COMPLICATIONS
FOB IN ICU 71
• Pneumothorax is described as a complication of TBLB in approximately 1% to
5%, and risk is especially high in patients under mechanical ventilation, in
which case it may reach 7% to 15% (rates of 23% have been described).
• the risk of pneumothorax after TBLB is higher without fluoroscopic control.
• Pneumothorax can also arise in patients under mechanical ventilation by
barotrauma (particularly if FOB is performed through an ETT with <8.0 mm
inner diameter or if ventilatory parameters are not properly adjusted).

CONTRAINDICATIONS
FOB IN ICU 73

CONTRAINDICATIONS
FOB IN ICU 74

CONTRAINDICATIONS
FOB IN ICU 75
• Thrombocytopenia is a relative contraindication for FOB. When
performing bronchoscopy only for simple airway examination,
there is a proposed cutoff of 20,000 to 50,000/ mL.
• BAL collection is a less risky procedure, and thus, it is
contraindicated only below 20,000 platelets/ mL.
• Most authors propose platelet counts above 50,000/ mL for
biopsies ( above 75,000/ mL for TBLB).

CONTRAINDICATIONS
FOB IN ICU 76
• Uremia is associated with platelet dysfunction and
carries some bleeding risk; thus, it has been suggested
that serum creatinine levels of 3 mg/dL or greater and
blood urea nitrogen levels of 30 mg/dL or greater should
be relative contraindications to performing TBLB.

CONTRAINDICATIONS
FOB IN ICU 77
• PT or APTT values greater than 1.5 times control increase
bleeding risk, there is no clearly defined cutoff above which
the procedure is contraindicated.
• PT >50 s has been proposed as a contraindication for BAL.
• For biopsies, it is generally agreed that clotting disorders should
be properly corrected, but there is no defined cutoff for PT or
APTT.

CONTRAINDICATIONS
FOB IN ICU 78
• In patients receiving oral anticoagulation, published guidelines suggest
stopping anticoagulants 3 days before the procedure or the
administration of low-dose vitamin K.
• In patients with high thromboembolic risk, in whom anticoagulation
cannot be stopped, international normalized ratio
should be kept under 2.5 and heparin started.
• clopidogrel greatly increases the risk of bleeding after TBLB and
recommend stopping the drug 5 to 7 days before the procedure.

Fob in icu. current practice

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