Respiratory pathophysiology 7 Flashcards
Here are the best predictors of postoperative pulmonary complications for patients undergoing pulmonary surgery:
FEV1 <40% predicted
DLCO <40% predicted
VO2 max <15 mL/kg/min
___________ is indicated when preoperative assessment suggests an increased risk of postoperative pulmonary complications
Split lung V/Q function testing
Absolute indications for one-lung ventilation include
infection
massive hemorrhage
bronchopleural fistula
Relative indications for one-lung ventilation include
improved surgical exposure
pulmonary edema
severe hypoxemia d/t lung disease
Ideal DLT sizing for females is
35-37 French
Ideal DLT sizing for males is
39-41 French
DLTs should not be used for
children under 8 years of age
Options for OLV in children under 8 include
a bronchial blocker or single lumen tube advanced into the main bronchus
Double-lumen ETTs can be
left or right sided
A __________ double-lumen is typically preferred
left
A right-sided DLT may be best in the following situations:
left main bronchus has distorted anatomy (tumor, TAA)
surgical procedures including left pneumonectomy, left lung transplant or left sleeve resection
Tests for pulmonary surgery address these 3 things:
lung parenchymal function (gas exchange)
respiratory mechanics (airflow)
cardiopulmonary reserve
A 35 french tube is indicated for
females <160 cm
A 37 French tube is indicated for
females >160 cm
Insertion depth of a DLT for females is
27 cm
A 39 French tube is indicated for
males <170 cm
A 41 French tube is indicated for
males >170 cm
Insertion depth of a DLT for males is
29 cm
The best size DLT for an 8 year old is
26 French
The best size DLT for 10 years old and up is
28-32 French
During anesthesia in the lateral decubitus position, the non-dependent lung is
better ventilated and the dependent lung is better perfused (V/Q mismatch)
During one-lung ventilation, there’s a mixing of blood from the non-dependent (non-ventilated) lung and the dependent (ventilated) lung, this leads to
increased shunt fraction and is a significant source of hypoxemia
Suggestions for initiating OLV include:
FiO2 100%
Vt: 6-8 mL/kg IBW
RR: 12-15 breaths/min.
ARM before starting OLV
assess serial ABGs after OLV is started
Consider PEEP 5-10 cmH2O
adjust the I:E ratio if the pt. has an expiratory air flow limitation
Consider TIVA vs. volatile anesthetic
Stepwise approach to hypoxemia during OLV:
- verify delivery of 100% oxygen
- check the position of tube/bronchial blocker via fiberoptic bronchoscopy
- R/o physiologic causes of hypoxemia, such as reduced CO, bronchospasm, mucus plug, pneumothorax
- Apply CPAP to the non-dependent lung or use a suction catheter to insufflate O2
- Apply PEEP 5-10 cmH2o to dependent lung
If the stepwise approach to hypoxemia for OLV didn’t work, the options include
intermittently reinflate the non-dependent lung
ligate the pulmonary artery
eliminate drugs that inhibit hypoxic pulmonary vasoconstriction
If the DLT is in too far, the
upper lobe is not ventilated (increased risk of hypoxemia)
If the DLT is not deep enough,
there will be failure to achieve lung separation
If the DLT is in the wrong bronchus, the
wrong lung collapses
Is hypoxemia during OLV more common during surgery on the right or left lung?
right lung- the left lung is smaller than the right so there’s less surface area for gas exchange when the left lung is ventilated (during right lung surgery)
Unlike a DLT, the bronchial blocker CANNOT (select 3):
a. insufflate oxygen into the isolated lung
b. ventilate the isolated lung c. provide lung separation in the patient requiring nasotracheal intubation
d. prevent contamination from contralateral lung infection
e. provide lung separation in children
f. suction secretions from the isolated lung
b. ventilate the isolated lung
d. prevent contamination from contralateral lung infection
f. suction secretions from the isolated lung
A bronchial blocker placed through
a single lumen endotracheal tube is an alternative method of providing OVL
An advantage of the bronchial blocker is that the patient won’t need
to be reintubated with a single lumen ETT if he requires postoperative ventilation
Downsides of a bronchial blocker include
the operative lung is slow to collapse (b/c the lumen of the BB is narrow)
high-pressure balloon can easily slip to enter the trachea which can lead to contamination and even block ventilation of both lungs
Examples of why you would use a bronchial blocker instead of a DLT include:
children <8 years old
patient requires nasotracheal intubation
patient has a tracheostomy
there’s already a SL ETT in place
patient requires intubation after surgery & want to avoid changing the DLT
Several types of bronchial blockers include
EZ
Cohen
Arndt
Uniblocker
Identify the MOST common serious complications of mediastinoscopy (select 2):
a. chylothorax
b. pneumothorax
c. left recurrent laryngeal nerve injury
d. hemorrhage
b. pneumothorax
d. hemorrhage
Mediastinoscopy is performed to
diagnose and stage lung cancer
The most common serious complications of mediastinoscopy include
hemorrhage (#1) & pneumothorax (#2)
An absolute contraindication to mediastinoscopy is
previous mediastinoscopy (d/t scarring)
Since hemorrhage is a risk with mediastinoscopy, it is necessary to have
large bore IV access and PRBCs available
Compression of the innominate artery with mediastinoscopy can
impair cerebral perfusion (right side of the circle of Willis)
Where you place your monitors is important for monitoring
compression of the innominate artery
pulse oximeter & arterial line on RUE
If the scope compresses the innominate artery, the
waveform of the pulse ox or arterial line will dampen or disappear
There is an association between oat cell carcinoma and
Eaton-Lambert syndrome
Patients with Eaton-Lambert syndrome are sensitive to
both succinylcholine and non-depolarizers
Indications for tracheal resection include
tracheal stenosis
tracheomalacia
tumor
vascular lesions
congenital malformations
To reduce tension on the tracheal anastomosis, the patient’s
neck must maintain a flexed position for several days after surgery
The best choice if a patient needs to be reintubated postoperatively after a tracheal anastomosis is
flexible fiberoptic bronchoscopy
Vital structures at risk for injury during mediastinoscopy include
thoracic aorta (hemorrhage and reflex bradycardia)
innominate artery (decreased carotid & cerebral blood flow)
vena cava (hemorrhage)
trachea (airway obstruction)
thoracic duct (chylothorax)
phrenic and recurrent laryngeal nerve (paresis)
Relative contraindications to mediastinoscopy include
tracheal deviation
thoracic aortic aneurysm
superior vena cava obstruction
A complication of neck hyperflexion is
tetraplegia
