ch 39 atelectasis and overview of LET Flashcards
define atelectasis
alveolar collapse
what are 3 pulmonary complications seen with patients who undergo thoracic or abdominal surgery
atelectasis, pneumonia, acute respiratory failure
most common form of therapy used in high risk patients after surgery
lung expansion therapy
lung expansion therapy includes what 5 modalities that are designed to prevent or correct atelectasis
- intermittent positive airway pressure breathing (IPPB)
- positive expiratory pressure (PEP)
- continuous positive airway pressure (CPAP)
- incentive spirometry (IS)
- deep breathing/directed cough
the common purpose of all 5 lung expansion therapies is
guiding the patient into improving pulmonary function by maximizing alveolar recruitment and optimizing airway clearance
true or false: there is no precise method to apply in a given situation bc there has not been any one method proved superior to other methods of LET (lung expansion therapy)
true
what is the common factor that all the LET modalities share
they are all designed to increase functional residual capacity (FRC)
what 4 things should a RT assist the physician in
- identifying patients most likely to benefit from LET
- recommend/initiate the appropriate and most efficient therapeutic approach
- monitor the patients response
- alter the treatment regimen as needed
the 2 types of atelectasis associated with postoperative or bedridden patients who are breathing spontaneously w/o mechanical assistance are
- gas absorption atelectasis
2. compression atelectasis
when can gas absorption atelectasis occur
either when there is a complete interruption of ventilation to a section of the lung (or) when there is a significant shift in v/q (ventilation/perfusion)
during gas absorption atelectasis what causes the partial collapse of the alveoli
gas that is absorbed by the passing blood DISTAL to the obstruction, causing the partial collapse of the nonventilated alveoli
define lobar atelectasis
when ventilation is compromised to a larger airway or bronchus
what does transmural pressure do
distends and maintains the alveoli in an open state
when does compression atelectasis occur
when the forces within the chest wall and lung (pleural pressure) are exceeded by the transmural pressure
what causes compression atelectasis
persistent use of small tidal volumes by the patient and when the patient does not periodically take a deep breath in and expand the lungs fully
when is it common to find someone using small tidal volumes
- general anesthesia is given
- use of sedatives and bed rest
- when deep breathing is painful (after surgery)
- weakening or impairment of the diaphragm
what type of atelectasis is common in hospitalized patients
compression atelectasis
true or false compression atelectasis and gas absorption atelectasis can occur simultaneously and why
true – may occur in a patient with excessive airway secretions who breathes with small tidal volumes for extended period of time
when can atelectasis occur in a patient
when the patient does not or cannot take deep breaths periodically and in patients who are restricted to bed for any reason
patients who have difficulty taking deep breaths without assistance include
- patients with significant obesity
- neuromuscular disorders
- under heavy sedation
- patients who have undergone upper abdominal or thoracic surgery
what are the major contributors to the onset of atelectasis
- diaphragmatic position
2. function of the diaphragm
in an anesthetized patient what shift of the diaphragm occurs
cephalad (toward the head) shift
for patients who are supine what part of the diaphragm is used the most
the lower, dependent portion of the diaphragm performs the most movement
for patients who are paralyzed what part of the diaphragm is used the most
the upper portion of the diaphragm
patients undergoing lower abdominal surgery are at _____ risk for atelectasis than patients undergoing upper abdominal or thoracic surgery
lower
patients with spinal cord injuries are most prone to what type of respiratory complication
atelectasis
bedridden patients (recovering from trauma) are predisposed to what type of conditions (2)
lack of mobility and development of atelectasis
atelectasis is the biggest determinate to what post abdominal surgery
hypoxemia
_____ percentage of deaths occur from atelectasis within ____ days of surgery
24% and within 6 days of surgery
impairment of the function of __________ ____________ also impacts the development of atelectasis
pulmonary surfactant
what do surfactants do in the lungs
decrease the surface tension of the walls of the alveoli
when there is deterioration of surfactant function what occurs
the relative increase in surface tension can cause the walls of the alveoli to collapse
why do most postoperative patients have trouble coughing
because of their reduced ability to take deep breaths
ineffective cough impairs ______ which leads to increased retain of ________
impairs normal clearance mechanism leading to increases in retained secretions
what type of atelectasis does an increase in retained secretions lead too and why
development of gas absorption atelectasis in a patient with excessive mucus production
what type of patients are more prone to develop increased retained secretions
patients with preexisting lung disease with increased mucus production like chronic bronchitis or chronic smokers
lung expansion therapy and chest physical therapy in the postoperative period help improve what
clearance of secretions by improving the effectiveness of coughing and secretion removal
if the incision is close to the diaphragm the chances of _______ goes up
greater risk of postoperative atelectasis
how does inadequate nutrition increase the risk for postoperative atelectasis
most likely due to inadequate strength of the inspiratory muscles to maintain a normal FRC and VC
what levels show inadequate nutrition that could lead to increased risk for pulmonary complications
albumin level less than 3.2 mg/dL
what provides the first clue in identifying atelectasis
patients medical history
if the patient has minimal atelectasis then the signs may be
absent or very subtle
when atelectasis involves a more significant portion of the lungs the patients respiratory is related how
the patients respiratory rate increases proportionally
what sounds may be heard over the region of the atelectasis
fine, late-inspiratory crackles
what produces the crackles heard
sudden opening of distal airways with deep breathing
what breath sounds may be heard as the lung becomes more consolidated with atelectasis
bronchial type breath sounds
diminished breath sounds are common when
excessive secretions block the airways and prevent transmission of breath sounds
__________ heart rate may be present if atelectasis leads to significant ________
tachycardia , hypoxemia
patients with preexisting lung disease often present with significant abnormalities in __________ and _________ rates; even when atelectasis is not _________
respiratory
heart
severe
direct relationship between the ______________ respiratory rate and the ___________ of atelectasis present
spontaneous
degree
(directly related)
what is often done to confirm the presence of atelectasis
chest radiograph
in a x-ray the atelectatic region shows as
increased opacity
evidence of __________ _________ is present in patients with significant atelectasis
volume loss
direct signs of volume loss on the chest film include (3)
- displacement of interlobar fissures
- crowding of pulmonary fissures
- air bronchograms
indirect signs of volume loss on the chest film include (5)
- elevation of the diaphragm
- shift of the trachea, heart, or mediastinum towards side of atelectasis
- pulmonary opacification
- narrowing of the space b/w the ribs
- compensatory hyperextension of the surrounding lung
how do all modes of lung expansion therapy work
they increase lung volume by increasing the transpulmonary pressure (PL) gradient
what does the transpulmonary pressure gradient represent
the difference between the alveolar pressure (Palv) and the pleural pressure (Ppl)
what is the formula for the PL gradient
PL = Palv - Ppl
with all else being constant, the greater the PL gradient, the more that the alveoli will…
expand – directly related
how can the PL gradient be increased
- decrease the surrounding Ppl
2. increase the Palv
how does a spontaneous deep inspiration increase the PL gradient
by decreasing the Ppl
how does the application of positive pressure to the lungs increase the PL gradient
increasing the pressure inside the lungs
how does incentive spirometry work
it enhances lung expansion via a spontaneous and sustained decrease in Ppl
how does positive airway pressure techniques work
increases Palv in an effort to expand the lung
what method decreases Ppl
incentive spirometry
methods that decrease Ppl have a more ______ effect than the methods that increase Palv and often are most ________
physiologic
effective
what should the goal of any lung expansion therapy
implement a plan that provides an effective strategy in the most efficient manner
what two major issues are related to efficiency
staff time and equipment
what does positive pressure therapy require significantly more of
staff time and equipment
who is positive pressure therapy reserved for
high-risk patients who cannot perform IS techniques
