ARDS Flashcards
Spontaneous breathing is a _______ pressure driven cycle.
Negative
What 2 muscles contract during normal inspiration?
Diaphragm and intercostals
Describe normal inhalation.
Diaphragm flatens during contraction creating more space in chest which means less pressure in chest compared to atmospheric pressure to air rushes in bc of the decrease in intrapleural pressure.
Describe normal exhalation?
Expiratory phase is passive where diaphragm returns to normal position and lungs recoil and air is exhaled out
Pressure in alveoli during breathing process remains _______ so diffusion of gases occurs.
Positive
Define ventilation.
Movement of air into and out of lungs
Define perfusion.
Movement of blood flow
Define diffusion.
Gas exchange (CO2 and O2 being transported-works best when alveoli and capillary are close together)
Define hemodynamic.
Movement of blood
What are the hemodynamic effects of normal spontaneous breathing?
Increases venous return to R. atrium during inspiration
Increases pulmonary blood flow during inspiration
Increases cardiac output during inspiration
What is the biforcation (splitting) of the right and left mainstem?
Carina
What is Acutre Respiratory Distress Syndrome (ARDS)?
Rapid onset of non-cardiac pulmonary edema
Which of the following are true statements regarding the A/P of the resp. system? Select all that apply.
A. @ the end of inspiration the pressure in the alveoli is -
B. The R. lung has 3 lobes.
C. Physiological dead space includes the trachea, bronchi and bronchioles.
D. Normal resp. is a - driven cycle
E. Cilia action and mucus production are protective mechanisms to prevent infection.
B, C, D, E
At the beginning of inspiration the pressure in the alveoli is what?
Negative
At the end if inspiration the pressure in the alveoli is what?
0, it’s equal to atmospheric pressure
A pt. is diagnosed w/ a pulmonary emboli. This will primarily affect: A. Ventilation B. Perfusion C. Diffusion D. Osmosis
B. Perfusion
The amount of air inhaled and exhaled w/ a normal breath is the: A. Functional residual capacity B. Vital capacity C. Negative inspiratory force D. Tidal volume
D. Tidal volume
The amount of air left in the lungs after a normal exhalation is what?
Functional residual capacity
What is vital capacity?
The greatest amount of air that can be forced from the lungs after max. inhalation
What is negative inspiratory force?
Volume of air that’s inspired or expired during regular breathing
Tidal volume is based on what?
IDEAL body weight
What will you see w/ pulmonary emboli?
Hypoxia
The hemodynamic effects of normal spontaneous breathing is: A. Increased HR B. Decreased CO C. Increased pulmonary blood flow D. Vasoconstriction of pulmonary artery
C. Increased pulmonary blood flow
ARDS is a progressive refractory period; what does that mean?
Resistance to treatment; low pulse ox even after admin. of O2
What are the 2 most common causes of ARDS?
Trauma and sepsis
ARDS has extensive what?
Lung tissue inflammation
Aspiration pneumonia, inhaled toxins, pulmonary embolism and mechanical ventilation are examples of what type of injury?
Direct
Trauma, shock, sepsis, cardiac arrest, drug OD, acute pancreatitis, and O2 toxicity are examples of what type of injury?
Indirect
When do s/s start to appear w/ ARDS?
12-48hrs post injury
ARDS is the syndrome of what?
Inflammation and increased permeability
What keeps the alveoli open?
Surfactant
ARDS causes damage to what?
Alveolar-capillary membrane (space b/t alveoli and capillary; alveoli fills w/ fluid causing inflamm. which decreases surfactant and decreases gas exchange)
What is the goal of ARDS?
Preserve alveoli function (recruitment)
In the 1st phase of ARDS: acute injury what occurs in the 1st 24hrs?
Mild hypoxemia, dyspnea, tachypnea, resp. alkalosis, subtle changes in mentation, slight temp elevation, normal breath sounds and an occasional dry cough
What occurs in the latent period of ARDS b/t several hrs to 2 days?
Hypoxemi resistant to O2 therapy, may required use of mechanical ventilation, capillary congestion, microatelectasis
What occurs in the exudative phase of ARDS b/t 2-10days?
Onset of acute resp. failure, alveoli becomes edematous, surfactant becomes diluted, alveoli collapse and consolidates, s/s of systemic inflammatory response (SIRS)
What occurs in the fibroliferative phase of ARDS b/t 10days after injury?
Inflammation leads to fibrosis of alveolar-capillary membrane, severe physiologic abrnomalities, refractory hypoxemia, metabolic and resp. acidosis.
What occurs in the recovery/repair phase of ARDS?
Increase tissue oxygenation, decrease O2 consumption, and prevent complications
In the latent phase how does ARDS show up on a CXR and why?
Opacity bc normal alveoli is getting scarred
What is SIRS?
Group of s/s that mean massive inflammation
In the fibroproliferative phase pts become what bc they can’t get rid of the CO2?
Resp. acidosis
CPAP is use when what?
Pt is awake/cooperative and can’t maintain a PO2 greater than 50mmHG on O2 of 50% (short-term)
Mechanical ventilation does what?
Allows maintencance of adequate tissue oxygenation while correcting underlying cause and allowing lungs to heal
On mechanical ventilation enough O2 must be provided to prevent what but not cause what?
Cellular hypoxia; O2 toxicity
Increasing amounts of O2 cause cause more damage to what if a pt is on mechanical ventilation?
Damage to surfactant
Positive End Expiratory Pressure (PEEP) is used to?
Increase pO2 w/ lower fiO2
PEEP is used for pts who can’t what?
Maintain a pO2 greater than 60 on 50% O2 or less
PEEP does what?
@ end of expiration sends out positive pressure to alveoli to keep it open for diffusion of gases
PEEPs increases what?
Functional residual capacity and # and size of alveoli available
What type of tidal volumes need to be used in pts w/ ARDS to prevent what?
Small; barotrauma and hemodynamic changes
What is barotrauma?
High pressure in alveoli (want low)
To minimize O2 demand we want to give what type of meds to minimize muscle use and anxiety?
Sedatives and muscle relaxants to paralyze and sedate
What type of meds are used for pts w/ ARDS?
Corticosteriods, antibiotics, and nitric oxide
Why are corticosteroids controversial?
Decreases inflammation and cellular permeability
What is nitric oxide?
Local vasodilator, maximizes perfusion to improve oxygenation
Why are prophylaxis antibiotics controversial?
Increases risk for infection
What increases tissue oxygenation?
Prone positioning
Do not use prone positioning with what?
Unresolved ICP, hemodynamic instability
What decreases oxygenation consumption?
Rest and sleep, treating agitation, treating anxiety w/ sedatives or morphine-monitor RR
How do you treat hyperthermia and pain in pts w/ ARDS?
Cooling blankets, antipyretics, low dose analgesics
What is the goal of fluid management?
Maintain normal circulating blood volume
How do you manage fluid in a pt. w/ ARDS?
Prevent fluid overload, treat hypotension w/ vasopressors and PRBCs, use diuretics w/ caution bc decreases BP, and sometimes do hemodialysis
What is pulmonary hygiene in a pt w/ ARDS?
Prevent secondary infection, suction, chest PT and humidification
How many calories a day should a pt w/ ARDS eat?
3000 calories
How do you manage nutrition in a pt. w/ ARDS?
Enteral feedings and avoiding TPN
How does enteral feedings help w/ nutrition?
Prevents muscle catabolism and weakness of resp. muscles and helps immune system mobilize defenses
Why should you avoid TPN?
Increase risk for infection
Too much fluid in a pt. w/ ARDS can cause what?
Worsening of ARDS
Too little fluid in a pt. w/ ARDS can cause what?
Thickening of secretions
Too much food @ 1 time can cause what which can lead to what?
Diarrhea; skin breakdown
What is muscle catabolism?
Breakdown of muscles to get protein when it’s deficient
What are complications of ARDS?
Multi-system organ failure and infection
