ARDS + respiratory Flashcards
bronchial circulation
does not participate in gas exchange
left bronchiole circulation is rooted from aorta
right sided bronchioles are supplied by arteries (intercostal, subclavian, mammary)
veins empty into vena cava
ventilation
mechanical act of moving air into and out of respiratory tree
involves musculoskeletal and nervous sustems
respiration
process of transporting O2 and CO2 across alveolar capillary membranes by diffusion across concentration gradient
physiology of ventilation
diaphragm contracts and flattens
increases volume of thoracic cavity
creates a relative negative intrapulmonary pressure
compliance
ability of lungs and thorax to stretch and expand given a change in pressure
decreased in pulmonary fibrosis
increased in emphysema and COPD
age related changes
decreased cough/laryngeal reflexes
decrease in alveoli, respiratory muscle strength
increased VQ mismatches, AP diameter, residual volume
autonomic respiration
controlled by brainstem
voluntary ventilatory effort
controlled by cerebral cortex
central chemoreceptors
detect level of H ion in blood
peripheral chemoreceptors
sensitive to oxygen, CO2, and H levels
dead space units
ventilation exceeds perfusion
pulmonary embolism or pulmonary infarct
shunt unit
perfusion exceeds ventilation
pneumonia or atelectasis
silent unit
ventilation and perfusion are impaired
severe ARDS or pneumothorax
oxyhemoglobin dissociation curve
97% of O2 is bound to Hgb (SaO2)
3% dissolved in serum (PaO2)
shift right
fever
acidosis
rise in CO2 (hypercapnia)
rise in 2, 3 diphosphoglycerate
shift left
hypothermia
rise in pH (alkalosis)
low CO2
PaO2
80-100 mm Hg
reflects the partial pressure of O2 in arterial blood
SaO2
93-100%
represents saturation of Hgb with O2
type 1 respiratory failure
hypoxemic failure
stems from a disruption of O2 transport from alveolus to arterial flow
type 2 respiratory failure
hypoxemic hypercapnic failure
originates in musculoskeletal or anatomical lung dysfunction/suppression
high concentration of CO2 in alveolus = hypercapnia
inability to replace CO2 with O2 = hypoxemia
type 1 respiratory failure nursing dx
impaired gas exchange
r/t: alterations in alveolar capillary membrane, excessive secretions, VQ mismatch
type 1 respiratory failure interventions
provide supplemental O2
positioning
maintain airway patency
treat underlying causes of ACM alterations, VQ mismatches
type 2 respiratory failure nursing dx
ineffective breathing pattern
r/t: alveolar hypoventilation, musculoskeletal dysfunction, neurological trauma
type 2 respiratory failure interventions
provide mechanical ventilation as needed
treat causes of alveolar hypoventilation
optimize musculoskeletal dysfunctions
optimize neurological defects
s/s of hypoxia
tachypnea, dyspnea tachycardia, dysrhythmias HTN confusion, restlessness lethargy
low flow O2 therapy
nasal cannula (up to 6 LPM) simple mask (8-12 LPM) nonrebreather mask (prevent room air from being inhaled) Venturi mask (adjustable dial with desired FiO2 and LPM flow)
high flow O2 therapy
delivers O2 at higher rate than pt’s inspiratory flow rate
may have some positive pressure effect
wide nasal cannula, nasal pillow, face mask
mechanical ventilation
NIV or invasive
mechanical ventilation desired outcomes
relief of sx of respiratory distress rest fatigued muscles of respiration improved oxygenation, ventilation pH balance stabilization of chest wall provision of sedation/anesthesia
noninvasive ventilation (NIV) indications
COPD exacerbation
obesity hypoventilation syndrome
cardiogenic pulmonary edema
lung contusions
noninvasive ventilation contraindications
apnea
recent airway or GI surgery
noninvasive ventilation
supports ventilation without insertion of artificial airway
ventilation through upper airway using an interface with a tight seal
most common: CPAP, BIPAP
CPAP
continuous positive airway pressure
allows more lung units to be available for gas exchange
helps open alveoli and prevent atelectasis during expiration
increases partial pressure of O2 in the alveoli
BiPAP
bilevel posiive airway pressure
allows clinician to set higher inspiratory pressure and lower expiratory pressure
reduces work of breathing
noninvasive ventilation concerns
skin protection
anxiolytics
tissue ischemia 2/2 tight fit of mask
invasive mechanical ventilation
provided by positive pressure ventilator
positive pressure is applied at patient’s airway by means of naso/endotracheal tube or tracheostomy
endotracheal intubation
larygnoscope
stethoscope to auscultate for placement
suction with orotracheal device
bag valve mask
nursing actions during endotracheal intubation
alert physician to decreases in SaO2 below 90%
auscultate for correct tube placement
note marking on tube at lip
monitor for patient to wake because of choking sensation
tracheostomy indications
pts requiring long term mechanical ventilation (?21 days)
pts with airway obstruction
tracheostomy
incision in the neck at cricothyroid membrane to access trachea and create a stoma to insert tube
tracheostomy complications
bleeding infection ulceration dysphonia tube obstruction fistula
controlled mandatory ventilation
tidal volume delivered at a set rate independent of patient effort
assist-control ventilation (AC)
patient regains some control of rate of breathing
synchronized intermittent mandatory ventilation (SIMV)
patient receives a minimum number of breaths with set Vt
may take additional breaths as determined by the pt
CPAP ventilator setting
used frequently as pts become ready for extubation
often used in conjunction with pressure support ventilation to offer bilevel vent pressures
pressure control ventilation
less frequently used
provides a set pressure instead of tidal volume during respiratory cycle
apnea alarm
low minute volume alarm
check if pt is connected to ventilator
ensure pt is not overly sedated
pt may require higher level of ventilatory support
high pressure alarm
ensure tubing is not kinked or compressed
assess need for suctioning
assess for ventilator dyssynchrony
report alarm to responsible clinician
high minute volume alarm
assess for anxiety
assess for s/s hypoxia (tachycardia, HTN, restlessness, cyanosis)
pt may require higher level of vent support or sedation
endotracheal suction
every 2-4 hours
facilitates airway patency
ventilators and restraints
restraints prevent accidental extubation
ventilators and nutrition
early enteral nutrition reduces risk of nutritional deficiencies
routine GI assessment
aspiration risk
weaning protocols
is pt: hemodynamically stable? SaO2 > 92% ? able to follow simple commands? FiO2/ABGs
acute respiratory distress syndrome (ARDS)
inflammatory disorder that damages the alveolar capillary membrane and interferes with gas exchange
2/2 sepsis usually
ARDS criteria
- acute onset hypoxemia
- diffuse b/l opacities on chest radiography that cannot be explained by HF or nodules
- moderate to severe impairment of oxygenation
exudative phase of ARDS patho
capillary membranes leak and protein rich fluid fills alveoli
type 1 alveolar cells destroyed
hyaline membranes are formed
exudative phase of ARDS assessment
chest x-ray may be normal or show dependent infiltrates
tachypnea, dyspnea
change in LOC
lung sounds may be clear
fibroproliferative phase of ARDS patho
type II alveolar cells are damaged surfactant production declines peak inspiratory pressure increases compliance declines V/P mismatch
fibroproliferative phase of ARDS assessment
chest x ray shoes diffuse b/l infiltrates and elevated diaphragm refractory hypoxemia with hypercarbia crackles on auscultation right HF develops agitation
recovery/fibrotic phase of ARDS patho
development of fibrotic tissue in the ACM resulting in alveolar disfigurement
decreased compliance
pulmonary HTN
dead space ventilation increased
recovery/fibrotic phase of ARDS assessment
leukocytosis, fever worsening infiltrates on CXR decreased tissue perfusion tachycardia + hypotension lactic acidosis end-organ dysfunction
early s/s of ARDS
dyspnea, tachypnea cyanosis abnormal breath sounds change in LOC confusion retrosternal discomfort fever
vent management of ARDS
tidal volume 4-8mL/kg plateau pressure <30 cm H2O FiO2 > 60% judicious use of PEEP permissive hypercapnia maintain SaO2 88-95%
extracorporeal life support (ECMO) indications
ARDS with:
severe hypoxemia
uncompensated hypercapnia, pH <7.15
end expiratory plateau pressures >35-45 cm H2O who fail prone positioning trial
ARDS medications
neuromuscular blocking agents statins corticosteroids vasodilators surfactant beta agonists
contraindications for prone positioning
spinal injuries
elevated ICP
abdominal compartment syndrome
hemodynamic instability
