5. Acute Respiratory Failure

Question 1

Acute Respiratory Failure is defined as

Answer 1

a RAPIDLY occurring inability of the lungs to maintain adequate oxygenation of the blood with or without impairment of carbon dioxide (CO2) elimination.

Specifically, the ABG demonstrates:
PaO2 of 60 mmHg or less, with or without an elevation of PaCO2 to 50 mmHg or more with pH <7.30

Question 2

The primary problem of Acute Respiratory Failure may be

Answer 2

one of hypoxemia (type 1) or hypercarbia (type 2) or both (type 3)

Question 3

Type 1 (hypoxemic)

Answer 3

-ARDS
-Asthma
-Atelectasis
-Interstitial fibrosis
-Pneumonia
-Pulmonary edema (heart failure)
-Pulmonary embolism (massive)
-Smoke inhalation

Question 4

Type 2 (hypercapnia)

Answer 4

-CNS depression due to oversedation
-COPD (acute exacerbation)
-Head trauma
-Musculoskeletal disorders or trauma
-Sleep apnea
-Status asthmaticus

Question 5

Type 3:

Answer 5

-ARDS (late)
-COPD (late, acute exacerbation)
-Status asthmatics (late)

Question 6

Clinical signs and symptoms of acute HYPOXEMIC Respiratory Failure

Answer 6

-Pulmonary: tachypnea, adventitious breath sounds,
accessory muscle use.

-Cardiac: tachyarrhythmias (initial), bradyarrhythmias
(late), hypertension or hypotension, cyanosis (central,
eg: lips, earlobes)

-Neurological: anxiety, agitation

Question 7

Clinical signs and symptoms of acute HYPERCAPNIC Respiratory Failure

Answer 7

-Pulmonary: shallow breathing, bradypnea, lungs may
be clear or there may be adventitious breath sounds

-Neurological: progressive decreased level of
consciousness (lethargic, obtunded, stuporous,
unresponsive).

Question 8

Acute Respiratory Failure ID & trmt:

Answer 8

Prompt identification and treatment may prevent a catastrophic outcome! The etiology of the signs/symptoms may not be the primary focus initially.

Question 9

Treatment of Acute Respiratory Failure

Answer 9

-Maintain airway and improve ventilation
-Optimize Oxygenation
-Optimize circulation, cardiac output
-Identify etiology: target treatment accordingly
-Provide emotional support

Question 10

Ways to maintain airway and improve ventilation in Acute Respiratory Failure

Answer 10

-Positioning (upright)
-Suctioning
-Bronchodilator therapy for wheezing
-Noninvasive ventilation
-Intubation, mechanical ventilation if needed
-Repeat ABGs as needed

Question 11

Ways to optimize oxygenation in ARF

Answer 11

-Adjust FiO2 to keep SaO2 ~ > 0.90
-Decrease FiO2 to 0.50 or less ASAP
-Do not allow hypoxemia to occur to “prevent O2 toxicity”
-Use PEEP/CPAP as needed
-Use pulse oximetry to monitor response to therapy

Question 12

Ways to Optimize Circulation, Cardiac Output in ARF

Answer 12

-Manage hypotension
-Address Cardiac Arrhythmias

Question 13

Use of Noninvasive Ventilation for the Management of Acute Respiratory Failure

Answer 13

When used for an appropriate pt, noninvasive ventilation (NIV) has been shown to decrease morbidity and mortality. There are 2 main types of NIV (exam doesn’t cover details related to type of NIV). Instead, understand those who would NOT benefit from this therapy. Occasionally, a pt may initially be a good candidate for NIV but then, due to a change in condition, the pt should be intubated with an ETT.

Question 14

2 types of NIV

Answer 14

CPAP & BiPAP

Question 15

CPAP

Answer 15

Continuous Positive Airway Pressure
-Indicated for pts with hypoxemic respiratory failure who have increased work of breathing (e.g., cardiogenic pulmonary edema)
-Settings include FiO2 and 1 pressure setting in cm H2O pressure.

Question 16

BiPAP

Answer 16

Bilevel positive airway pressure
-Indicated for pts with hypoxemic and/or hypercapnia respiratory failure
-Settings include FiO2 and 2 pressure settings: the inspiratory positive airway pressure (IPAP) and the expiratory positive airway pressure (EPAP).
-IPAP assists ventilation and EPAP assists oxygenation.

Question 17

Advantages of NIV

Answer 17

-Buys time for medical treatment to take effect
-Reduces the work of breathing (WOB)
-Decreases preload and afterload
-Improves Oxygenation
-Improves ventilation (BiPAP)
-Reduces atelectasis
-Prevents intubation and resultant risks

Question 18

Contraindications for NIV

Answer 18

-Hemodynamic instability or life-threatening arrhythmias
-Copious secretions
-High risk of aspiration
-Impaired mental status (unable to protect airway)
-Suspected pneumothorax
-Inability to cooperate
-Life-threatening refractory hypoxia (PaO2 < 60 with FiO2 1.00)

Question 19

HFNC

Answer 19

High-Flow Nasal Cannula (HFNC) Oxygen, which has long been used for pediatric and infant pop., is now used for select adult populations in the treatment of acute respiratory failure and post-extubation

Question 20

HFNC oxygen delivery systems are able to deliver ___

Answer 20

FiO2 (up to 100%) of heated and humidified gas at flow rates up to 60 L/min via a nasal cannula

Question 21

Advantages of HFNC therapy

Answer 21

-Able to provide high FiO2 (up to 100%)

-Heated and humidified oxygen may improve secretion clearance and decrease airway inflammation

-Able to meet high inspiratory flow demands of tachypneic pts

-seems to promote alveolar recruitment and increase FRC

-Decreases dead space ventilation

-more comfortable than CPAP or BiPAP masks, allows access to the mouth without removal of a mask

Question 22

Limitations of HFNC therapy

Answer 22

-Unable to deliver higher airway pressures (PEEP or CPAP), and the low levels of airway pressure provided are variable when mouth breathing

-Provides limited pressure support for a pt with hypercapnia respiratory failure

Question 23

Indications of HFNC therapy:

Answer 23

-Community-acquried pneumonia
-Cardiogenic pulmonary edema when NIV is not tolerated
-Preoxygenation prior to intubation
-Post-extubation (even in low-risk pts)
-For a pt who refused intubation (DNI) but accepts alternate treatment measures
-HFNC oxygen therapy may also be used in conjunction with NIV post-extubation to prevent re-intubation

Question 24

Nursing implications for HFNC therapy:

Answer 24

-Monitor for deteriorating oxygenation/ventilation (the pt may require NIV or intubation and mechanical ventilation)
-Assess for nasal skin irritation.