1) Respiratory failure can be caused by oxygenation failure (type I) or ventilatory failure (type II), classified based on blood gas levels of PaO2 and PaCO2. 2) Oxygenation failure is characterized by low PaO2 while ventilatory failure is characterized by high PaCO2. Both can cause acidosis. 3) Causes of respiratory failure include central nervous system issues, neuromuscular diseases, pulmonary diseases like COPD, and drug overdoses. Treatment depends on the underlying cause and may include oxygen therapy, non-invasive ventilation, or mechanical ventilation.

1. RT 7
M. Welch, RRT, RCP
Professor
ELAC / SMC RT Program
Spring 2022

2. Respiratory failure is syndrome rather
than single disease process. RECALL:
 Oxygenation failure = Type I
◦ PaO2 < 60 mm Hg at FiO2 > .50
 Ventilatory failure = Type II
◦ PaCO2 > 45 mm Hg
 Classification relates to the absence
or presence of hypercapnia
respectively.

3.  Oxygenation Failure = Type I
◦ Characterized by an arterial
oxygen tension (Pa O2) lower than
60 mm Hg w/ normal or low
carbon dioxide tension (Pa CO2).
◦ Most common form of respiratory
failure
◦ Can be associated with virtually all acute
diseases of the lung which generally involve
fluid filling or collapse of alveolar units

4.  Ventilatory failure = Type II
◦Characterized by a PaCO2 higher
than 45 mm Hg.
◦ Hypoxemia common in patients w/
hypercapnic respiratory failure who
are breathing room air.
◦ pH depends on the level of
bicarbonate, which is dependent on
the duration of hypercapnia.

6.  Acute: abnormal elevation of the
PaCO2 without renal compensation
 Chronic: abnormal elevation of the
PaCO2 with renal compensation
(abnormal Base Excess [BE] with the
pH in normal range)
 Mixed: a combination of acute and
chronic (abnormal BE but the pH is not
in the normal range)

7. Acute RF
Chronic RF
 Develops over
minutes to hours
 ↓ pH quickly to <7.2
 Examples:
Pneumonia,
 ARDS
 P/O Pt’s
 Develops over
days
 ↑ in HCO3
 ↓ pH slightly
 Polycythemia, Cor
pulmonale
 Example: COPD

8.  Dysfunction of Central Nervous
System (CNS)
◦(Depression of respiratory centers)
Drug Overdose
Head Trauma
Infection
Hemorrhage
Sleep Apnea

9. ◦Neuromuscular disease
Cerebral disease
Spinal cord trauma / injury
abnormalities
Muscular diseases
 Myasthenia Gravis
 Guillian-Barre syndrome
 Poliomyelitis
 Amyotropic Lateral Sclerosis / ALS
 AKA?


10. Musculoskeletal Dysfunction
◦Chest Trauma
◦Thoracic cage abnormalities
 Kyphoscoliosis
◦Upper and lower airway
obstruction
◦Malnutrition & electrolyte
disturbances

11. Pulmonary Dysfunction
◦Emphysema
◦Chronic Bronchitis
◦Asthma
◦Cystic Fibrosis
◦Restrictive lung diseases

12. e.g. Drug overdose
Change in respiration
Acidosis
Elevated PaCO2

13. Pathophysiology:
◦Increased PaCO2
◦decreased pH
◦Acidosis
◦Somnolence
◦Coma

15.  Respiratory failure may be associated
with a variety of clinical
manifestations.
◦ However, most are nonspecific, & very significant
respiratory failure may be present without
dramatic signs or symptoms.
 This emphasizes the importance of
measuring arterial blood gases in all
patients who are seriously ill or in whom
respiratory failure is suspected.

16.  Complete blood count (CBC) may
indicate anemia
◦ can also contribute to tissue hypoxia
◦ polycythemia may indicate chronic hypoxemic
respiratory failure.
 A chemistry panel may be helpful in the
evaluation and management of a patient in
respiratory failure.
◦ Abnormalities in electrolytes such as potassium,
magnesium, and phosphate may aggravate
respiratory failure and other organ function.

17.  Chest radiography is essential in
evaluation of respiratory failure because
it frequently reveals cause.
◦ Distinguishing between cardiogenic & noncardiogenic
pulmonary edema often difficult.
 Increased heart size / vascular redistribution /
peribronchial cuffing
 pleural effusions / septal lines / perihilar bat-wing
distribution of infiltrates suggest hydrostatic edema
◦ the lack of these findings suggests acute respiratory
distress syndrome (ARDS).

18.  Patients with acute respiratory
failure generally are unable to
perform PFTs;
◦These tests most useful in the
evaluation of chronic respiratory
failure.

19. Nonspecific:
◦Headache
◦Diminished alertness
◦Warm & flushed skin
◦Bounding peripheral pulses
◦Hypothermia and altered mental
status = drug OD

20. Nonspecific:
◦Tachycardia & hypertension
◦Respiratory alternans or
abdominal paradox
 = diaphragmatic fatigue
◦Hypoxemia is often seen in
conjunction with ventilatory
failure

21. Laboratory abnormalities
(ABG)
◦High PaCO2
◦Acidemia if Acute
◦Elevated total CO2 on
electrolyte panel

22. •Specific treatment of oxygenation &
/or ventilatory failure C/B Drug
Overdose (Narcotic / Barbiturate / alcohol )
 Identify type of drug, amount ingested and time
since ingestion.
 Diagnose and treat trauma.
 Prevent and/or treat aspiration; look for right lower
lobe crackles
 intubate if suspected or confirmed
 CMV to reestablish and maintain normal PaCO2
 100% oxygen initially then reduce FIO2 to maintain
clinical oxygenation

23. •Specific Treatment of oxygenation
& /or ventilatory failure C/B Drug
Overdose (Narcotic / Barbiturate / alcohol)
 Prevent drug absorption:
 Stomach lavage
◦ watch for aspiration
 Induce vomiting
 Charcoal
 Dialysis
 Administer antidote, i.e.: Narcan, etc.
 Psychiatric consult

24. ◦IF severe/acute most likely
invasive MV
◦HOWEVER:
◦IF patient awake and able to
cooperate with care and is
suspected COPD or CHF
Exacerbation: NIV is now the
preferred approach
◦IF NIV fails, then MV is instituted

25.  PRIOR to NIV, often the following are considered:
◦ HFNC What are the possible beneficial effects?
 High-flow system to deliver known FIO2
 Provide small amount of “CPAP” 2-5 or 6 cmH2O ?
1 cmH2O per every 10 Lpm?
 “wash out” anatomical deadspace of oralpharynx
 Reduce Insp. WOB by small, but statistically significant
amount
 Potential benefits of heated humidification on mucus? Not
well studied, but appears to have some “clinical effect”?
◦ Very frequent/intensive bronchodilators? (COPD Pt)
◦ MediNeb therapy? (COPD Pt)
◦ CPAP? (Defined as NIV by many)
 What is the PRIMARY difference between CPAP and BiPaP?

26. Mechanical ventilation
 First: Rapid Sequence Intubation f/b
◦ VT 5–8 ml/kg IBW
◦ Keep Pplateau < 35 cm H2O
◦ Respiratory rate according to age and
metabolic rate
◦ FiO2 adjusted with pulse oximetry
◦ Treat cause of ventilatory failure
◦ Wean from CMV as soon as possible
(ASAP)

27. Weaning criteria
◦ Etiology of ventilatory failure resolved
◦ Patient’s condition stable and improving
◦ Vital capacity (VC) > 10–15 mL/kg
◦ Resting minute volume < 10 L/min
◦ MIP > -20 cm H2O
◦ Adequate oxygenation on FiO2 < .50
◦ Spontaneous respiratory rate < 35
breaths/min
◦ Spontaneous tidal volume > 325 mL

28.  Weaning Methods:
◦SIMV
 Decrease number of mechanical breaths until
support is no longer necessary
◦Pressure Support
 Set to acceptable tidal volume and rate without use
of accessory muscles and wean thereafter
◦ T-Piece
 AKA: SBT (Spontaneous Breathing Trial)
 Temporary discontinuation of mechanical ventilation
 “Blow-by” of appropriate FiO2

29.  Complications of acute respiratory
failure may be:
◦ Pulmonary
◦ Cardiovascular
◦ Gastrointestinal (GI)
 Stress ulceration common
◦ Infectious
◦ Renal
 Acute renal failure & electrolyte abnormalities
◦ Nutritional
 Malnutrition & effect on respiratory performance

30.  Common pulmonary complications include:
◦ Pulmonary embolism
◦ Oxygen toxicity
◦ CO2 narcosis
◦ Barotrauma
◦ Pulmonary fibrosis
◦ Complications secondary to the use of CMV devices
 Patients also prone to develop nosocomial
pneumonia (VAP)
 Pulmonary fibrosis may follow acute lung
injury associated with ARDS.

31.  Common cardiovascular complications
include:
◦ Hypotension
◦ Reduced cardiac output
◦ Arrhythmia
◦ Pericarditis
◦ Acute myocardial infarction (AMI)
 These may be related to the underlying
disease process, mechanical ventilation, or
the use of pulmonary artery catheters

32.  Frequent infectious complications
or nosocomial infections such as:
◦ Pneumonia
◦ Urinary tract infections (UTI’s)
◦ Catheter-related sepsis
 These usually occur with the use of
mechanical devices.
 Incidence of nosocomial pneumonia is
high & associated with significant
mortality.

33.  Mortality associated with respiratory
failure varies according to the etiology.
◦ For ARDS, mortality is approximately 40-45%;
 This figure has not changed significantly over the
years.
◦ Younger patients (< 60 y) have better survival
rates than older patients.
◦ Approximately two thirds of patients who
survive an episode of ARDS manifest some
impairment of pulmonary function 1 or more
years after recovery.

34. ◦ Significant mortality also occurs in patients
admitted with hypercapnic respiratory failure.
 Often because these patients have a chronic
respiratory disorder & other comorbidities such as
cardiopulmonary, renal, hepatic, or neurologic
disease.
 These patients also may have poor nutritional status.
◦ For patients with COPD and acute respiratory
failure, the overall mortality has declined from
approximately 26% to 10%.
◦ Acute exacerbation of COPD carries a mortality
of approximately 30%.

35. “A surplus of effort
can overcome a
deficit of
confidence."
Sonia Sotomayor, 2013