1. Acute Respiratory Failure

2. Respiratory System Consists of two parts:
Gas exchange organ (lung): responsible for OXYGENATION
Pump (respiratory muscles and respiratory control mechanism): responsible for VENTILATION
NB: Alteration in function of gas exchange unit (oxygenation) OR of the pump mechanism (ventilation) can result in respiratory failure

3. Normal Lung

4. Lung Anatomy

5. Normal Alveoli

6. Gas Exchange Unit
Fig. 66-1

7. Normal ABGs
pH =
CO2 = 35-45
HCO3= 23-27

8. Respiratory and Metabolic Acidosis and Alkalosis
CO2 is an acid and is controlled by the Respiratory (Lung) system
HCO3 is an alkali and is controlled by the Metabolic (Renal) system
Respiratory response is immediate; Metabolic response can take up to 72 hours to respond (except in patients with COPD who are in a constant state of Compensation!)

9. ABG Interpretation Step 1:
Check the pH: Is it acidotic or alkalotic or normal? pH below 7.35 is acidotic; pH above 7.45 is alkalotic
If pH is normal, then the ABG is compensated; if pH not normal, then the ABG is uncompensated

10. ABG Interpretation (cont’d)
Step 2.
Check the CO2 and HCO3:
If the CO2 (acid) is above 45, the pt is acidotic; if the CO2 is below 35, the pt is alkalotic
If the HCO3 is above 27, the patient is alkalotic; if the HCO3 is below 23, the patient is acidotic

11. ABG Interpretation (cont’d)
Step 3
If the CO2 is high (above 45), then the patient is in Respiratory Acidosis; if the CO2 is low (below 35), then the patients is in Respiratory Alkalosis.
If the HCO3 is high (above 27), then the patient is in Metabolic Alkalosis; if the HCO3 is low (below 23), then the patient is in Metabolic Acidosis.

12. ABG Example #1
pH = 7.36
CO2 = 41
HCO3 = 27
Diagnosis: ?

13. ABG Example #2
pH = 7.49
CO2 = 37
HCO3 = 32
Diagnosis: ?

14. ABG Example #3
pH = 7.29
CO2 = 50
HCO3 = 26
Diagnosis: ?

15. ABG Example #4
pH = 7.40
CO2 = 32
HCO3 = 30
Diagnosis: ?

16. Acute Respiratory Failure
Results from inadequate gas exchange
Insufficient O2 transferred to the blood
Hypoxemia
Inadequate CO2 removal
Hypercapnia

17. Acute Respiratory Failure with Diffuse Bilateral Infiltrates

18. Acute Respiratory Failure
Not a disease but a condition
Result of one or more diseases involving the lungs or other body systems
NB: Acute Respiratory Failure: when oxygenation and/or ventilation is inadequate to meet the body’s needs

19. Acute Respiratory Failure
Classification:
Hypoxemic respiratory failure (Failure of oxygenation)
Hypercapnic respiratory failure (Failure of ventilation)

20. Classification of Respiratory Failure
Fig. 66-2

21. Acute Respiratory Failure
Hypoxemic Respiratory Failure
PaO2 of 60 mm Hg or less
(Normal = mm Hg)
Inspired O2 concentration of 60% or greater

22. Acute Respiratory Failure
Hypercapnic Respiratory Failure
PaCO2 above normal (>45 mm Hg)
Acidemia (pH <7.35)

23. Hypoxemic Respiratory Failure Etiology and Pathophysiology
Causes:
Ventilation-perfusion (V/Q) mismatch
Shunt
Diffusion limitation
Alveolar hypoventilation

24. V-Q Mismatching
I) V/Q mismatch
Normal ventilation of alveoli is comparable to amount of perfusion
Normal V/Q ratio is 0.8 (more perfusion than ventilation)
Mismatch d/t:
Inadequate ventilation
Poor perfusion

25. Range of V/Q Relationships
Fig. 66-4

26. Hypoxemic Respiratory Failure Etiology and Pathophysiology
Causes V/Q mismatch
COPD
Pneumonia
Asthma
Atelectasis
Pulmonary embolus

27. Hypoxemic Respiratory Failure Etiology and Pathophysiology
II) Shunt
An extreme V/Q mismatch
Blood passes through parts of respiratory system that receives no ventilation
d/t obstruction OR fluid accumulation
Not Correctable with 100% O2

28. Diffusion Limitations
III) Diffusion Limitations
Distance between alveoli and pulmonary capillary is one- two cells thick
With diffusion abnormalities: there is an increased distance between alveoli (may be d/t fluid)
Correctable with 100% O2

29. Hypoxemic Respiratory Failure Etiology and Pathophysiology
Causes Diffusion limitations
Severe emphysema
Recurrent pulmonary emboli
Pulmonary fibrosis
Hypoxemia present during exercise

30. Diffusion Limitation
Fig. 66-5

31. Alveolar Hypoventilation
IV) Alveolar Hypoventilation
Is a generalized decrease in ventilation of lungs and resultant buildup of CO2

32. Hypoxemic Respiratory Failure Etiology and Pathophysiology
Causes Alveolar hypoventilation
Restrictive lung disease
CNS disease
Chest wall dysfunction
Neuromuscular disease

33. Hypoxemic Respiratory Failure Etiology and Pathophysiology
Interrelationship of mechanisms
Hypoxemic respiratory failure is frequently caused by a combination of two or more of these four mechanisms
Effects of hypoxemia
Build up of lactic acid → metabolic acidosis → cell death
CNS depression
Heart tries to compensate → ↑ HR and CO
If no compensation: ↓ O2, ↑ acid, heart fails, shock, multi-system organ failure

34. Hypercapnic Respiratory Failure Etiology and Pathophysiology
Imbalance between ventilatory supply and demand
Occurs when CO2 is increased

35. Causes Hypercapnic Respiratory Failure
I) Alveolar Hypoventilation and VQ Mismatch:
Ventilation not adequate to eliminate CO2
Leads to respiratory acidosis
Eg. Narcotic OD; Guillian-Barre, ALS, COPD, asthma

36. Causes Hypercapnic Respiratory Failure
II) VQ Mismatch:
- Leads to increased work of breathing
- Insufficient energy to overcome resistance; ventilation falls; ↑PCO2; respiratory acidosis

37. Hypercapnic Respiratory Failure Categories of Causative Conditions
I) Airways and alveoli
Asthma
Emphysema
Chronic bronchitis
Cystic fibrosis

38. Hypercapnic Respiratory Failure Categories of Causative Conditions
II) Central nervous system
Drug overdose
Brainstem infarction
Spinal cord injuries

39. Hypercapnic Respiratory Failure Categories of Causative Conditions
III) Chest wall
Flail chest
Fractures
Mechanical restriction
Muscle spasm

40. Hypercapnic Respiratory Failure Categories of Causative Conditions
IV) Neuromuscular conditions
Muscular dystrophy
Multiple sclerosis

41. Respiratory Failure Tissue Oxygen Needs
Major threat is the inability of the lungs to meet the oxygen demands of the tissues

42. Respiratory Failure Clinical Manifestations
Sudden or gradual onset
A sudden  in PaO2 or rapid  in PaCO2 is a serious condition

43. Respiratory Failure Clinical Manifestations
When compensatory mechanisms fail, respiratory failure occurs
Signs may be specific or nonspecific

44. Respiratory Failure Clinical Manifestations
Severe morning headache
Cyanosis
Late sign
Tachycardia and mild hypertension
Early signs

45. Respiratory Failure Clinical Manifestations
Consequences of hypoxemia and hypoxia
Metabolic acidosis and cell death
 Cardiac output
Impaired renal function

46. Respiratory Failure Clinical Manifestations
Specific clinical manifestations
Rapid, shallow breathing pattern
Sitting upright
Dyspnea

47. Respiratory Failure Clinical Manifestations
Specific clinical manifestations
Pursed-lip breathing
Retractions
Change in Inspiratory:Expiratory ratio

48. Respiratory Failure Diagnostic Studies
Physical assessment
ABG analysis
Chest x-ray
CBC
ECG

49. Respiratory Failure Diagnostic Studies
Serum electrolytes
Urinalysis
V/Q lung scan
Pulmonary artery catheter (severe cases)

50. Acute Respiratory Failure Nursing and Collaborative Management
Nursing Assessment
Past health history
Medications
Surgery
Tachycardia

51. Acute Respiratory Failure Nursing and Collaborative Management
Nursing Assessment
Fatigue
Sleep pattern changes
Headache
Restlessness

52. Acute Respiratory Failure Nursing and Collaborative Management
Nursing Diagnoses
Ineffective airway clearance
Ineffective breathing pattern
Risk for imbalanced fluid volume
Anxiety

53. Acute Respiratory Failure Nursing and Collaborative Management
Nursing Diagnoses
Impaired gas exchange
Imbalanced nutrition: less than body requirements

54. Acute Respiratory Failure Nursing and Collaborative Management
Planning
Overall goals:
ABGs and breath sounds within baseline
No dyspnea
Effective cough

55. Acute Respiratory Failure Nursing and Collaborative Management
Prevention
Thorough physical assessment
History

56. Acute Respiratory Failure Nursing and Collaborative Management
Respiratory Therapy
Oxygen therapy
Mobilization of secretions
Effective coughing and positioning

57. Acute Respiratory Failure Nursing and Collaborative Management
Respiratory Therapy
Mobilization of secretions
Hydration and humidification
Chest physical therapy
Airway suctioning

58. Acute Respiratory Failure Nursing and Collaborative Management
Respiratory Therapy
Positive pressure ventilation (PPV)

59. Acute Respiratory Failure Nursing and Collaborative Management
Drug Therapy
Relief of bronchospasm
Bronchodilators

60. Acute Respiratory Failure Nursing and Collaborative Management
Drug Therapy
Reduction of airway inflammation
Corticosteroids

61. Acute Respiratory Failure Nursing and Collaborative Management
Drug Therapy
Reduction of pulmonary congestion
IV diuretics

62. Acute Respiratory Failure Nursing and Collaborative Management
Drug Therapy
Treatment of pulmonary infections
IV antibiotics

63. Acute Respiratory Failure Nursing and Collaborative Management
Drug Therapy
Reduction of severe anxiety, pain, and agitation
Benzodiazepines
Narcotics

64. Acute Respiratory Failure Nursing and Collaborative Management
Medical Supportive Therapy
Treat the underlying cause
Maintain adequate cardiac output and hemoglobin concentration
Monitor BP, O2 saturation, urine output

65. Acute Respiratory Failure Nursing and Collaborative Management
Nutritional Therapy
Maintain protein and energy stores
Enteral or parenteral nutrition
Supplements