1. Respiratory: Respiratory Failure and ARDS
Marnie Quick, RN, MSN, CNRN

2. Normal Respirations: Tidal Vol; Inspiratory & Expiratory reserve Vol; Residual Vol; Vital Capacity; Anatomical dead space

3. Normal gas exchange in lung

4. Blood Supply to Lung

5. Respiratory Failure Not a disease process, sign of severe dysfunction
Results when one or both gas exchanging systems inadequate; atmosphere (to lung) or blood
Alveolar ventilation inadeq to meet body’s need
Commonly defined in terms of ABG’s:
PO2 of less than 50 mmHg
PCO2 greater than 50 mmHg
Arterial pH of less than 7.35

6. Predisposing factors for Resp Failure: Airways/alveoli; CNS; Chest Wall; Neuromuscular- Table in Lewis p Most common cause: COPD

7. Classification of Respiratory Failure

8. Hypoxemic Respiratory Failure
Oxygenation failure- inadequate O2 transfer between alveoli & pulmonary capillary bed
PaO2: 60 mm Hg or less on 60 % O2
Inadequate O2 saturation of hemoglobin
Causes tissue hypoxia> Metabolic acidosis; cell death; decreased CO; impaired renal function
Common causes: disorders that interfere with O2 transfer into the blood- respiratory or cardiac system (Lewis p Table 68-1)

9. V/Q: Volume blood perfusing lungs each minute
Hypoxemic Respiratory Failure Mechanisms that may lead to Hypoxemia: 1. Mismatch ventilation & perfusion (V/Q mismatch)
V/Q: Volume blood perfusing lungs each minute
Each ml of air for each ml of blood
1:1= V/Q ratio of 1
Causes of V/Q mismatch:
Ventilation portion blocked (secretions in airway/alveoli, airway/alveolar collapse, decreased movement chest/ventilation)
Perfusion portion blocked (pulmonary embolus)
Treat: O2(reverse hypoxemia); treat cause

10. Hypoxemic Respiratory Failure Range of ventilation to perfusion (V/Q relationship)
A. Absolute shunt, no ventilation fluid in alveoli
B. Ventilation partially compromised- secretions
C. Normal lung unit
D. perfusion partially compromised by emboli obstructing blood flow
E. Dead space: no perfusion- obstruction of pulmonary capillary

11. Occurs when blood leaves heart without gas exchange
Hypoxemic Respiratory Failure Mechanisms that may lead to Hypoxemia: Shunt- Extreme V/Q mismatch
Occurs when blood leaves heart without gas exchange
Types:
1. anatomic shunt: O2 blood does not pass through lungs
2. intrapulmonary shunt- alveoli fill with fluid
Treatment: Mechanical ventilation to force O2 into lungs; treat cause

12. Hypoxemic Respiratory Failure Mechanisms may lead to Hypoxemia: 3
Hypoxemic Respiratory Failure Mechanisms may lead to Hypoxemia: Diffusion limitations
Alveoli membrane thickened or destroyed
Gas exchange across alveolar-capillary membrane can’t occur
Classic sign: hypoxemia present during exercise, not at rest
Treat the cause- pulmonary fibrosis; ARDS

13. Specific: Respiratory:
Hypoxemic Respiratory Failure Mechanisms may lead to Hypoxemia: Clinical Manifestations of Hypoxemia
Specific: Respiratory:
Dyspnea; tachypnea; prolonged expiration; intercostal muscle retraction; use of accessory muscles in resp;< 80% SpO2; paradoxic chest/abd wall movement with resp cycle (late); cyanosis (late)
Nonspecific:
Cerebral: agitation, disorientation, delirium, restless, combative, confusion, dec LOC, coma (late)
Cardiac: tachycardia, hypertension, skin cool/clammy, dysrhythmias (late), hypotension (late)
Other: fatigue; need to pause to breath when speaking

14. Hypercapnic Respiratory Failure
Ventilatory failure with insufficient CO2 removal
PaCO2 greater than 45 mm Hg
Arterial pH less than 7.35
PCO2 rises rapidly and respiratory acidosis develops: PO2 drops more slowly
Common causes: disorders that compromise lung ventilation and CO2 removal (Lewis Table 68-1)

15. Hypercapic Respiratory Failure
Ventatory failure: Inability of the respiratory system to ventilate out sufficient CO2 to maintain normal PaCO2
Specific Causes:
Airways/alveoli: asthma, COPD, cystic fibrosis
CNS: drug overdose- depressant, brainstem dysfuction, metabolic causing decreased LOC; high SCI injuries- decrease/absent diaphragm/chest movement
Chest wall: pain, flail chest, rib fractures, mechanical restriction, kyphoscoliosis, obesity
Neuromuscular: resp muscles weak/paralysis- MS, MG, MD, Guilain-Barre Syndrome

16. Hypercapic Respiratory Failure Clinical Manifestations
Specific:
Respiratory: Dyspnea; dec resp rate or rapid with shallow resp; dec tidal vol; dec min ventilation
Nonspecific:
Cerebral: AM headache; disorientation, progressive sommolence; coma (late)
Cardiac: dyshythmias; hypertension; tachycardia; bounding pulse
Neuromuscular: muscle weakness; dec deep tendon reflexes; Tremor/seizures (late)

17. Collaborative Care for Respiratory Failure: Diagnostic tests
History/physical assessment
Pulse oximetry
ABG analysis
Chest X-ray
CBC, sputum/blood cultures, electrolytes
EKG
Urinalysis
V/Q scan- if pulmonary embolism suspected
Hemodynamic monitor/pulmonary function tests

18. Collaborative care for Respiratory Failure Respiratory Therapy
Main treatment- correct underlying cause & restore adequate gas exchange in lung
Elevate HOB
Oxygen Therapy
Maintain PaO2 at least 60 mm Hg
SaO2 at least 90%
Mobilization of secretions
Hydration & humidification
Chest physical therapy
Airway suctioning
Effective coughing & positioning
Positive pressure ventilation
Noninvasive positive pressure ventilation
Intubation with mechanical ventilation

19. Collaborative Care for Respiratory Failure cont
Drug Therapy
Relief bronchospasm; reduce airway inflam and pulmonary congestion; treat pulmonary infections; reduce anxiety, pain
Medical supportive therapy
Treat underlying cause
Nutritional therapy
Enteral; parenteral
Protein and energy stores

20. Collaborative Care: Artifical airways- tracheostomy and endotracheal tubes

21. Endotracheal tube

22. Taping an endotracheal tube

23. Suctioning with closed (inline) suctioning -used with tracheostomy or endotrach tubes

24. Complications of endotracheal intubation
1. Extubation
Restraints
2. Aspiration
Tube at right allows for subglottal suctioning

25. Independent Lung Ventilation

26. Collaborative Care: Mechanical Ventilation
Provide adeq gas exchange
Types- Positive, Neg
Settings- Table 66-11
Modes- Table 66-12
Criteria to put on vent
RR > 35-45
pCO2 >45
pO2 <50

27. Types: Negative pressure ventilator

28. Types: Positive pressure mechanical ventilation with endotracheal tube (PPV)

29. Types: Positive pressure- Noninvasive (tight fitting mask) positive pressure ventilation (CPAP)

31. Settings and complications with mechanical ventilation

32. Ventilator settings (Table 66-11 p. 1761)

33. Alarm settings Assess your patient – not the alarm!!!!!
Never turn alarms off
Alarms sound when you have low pressure or high pressure in the ventilator
Note “alarm silence” and “alarm reset” on picture to the right

34. Low Pressure
Circuit leaks 
Airway leaks 
Chest tube leaks 
Patient disconnect from vent or tube
High Pressure
Patient coughing 
Secretions or mucus in the airway 
Patient biting tube 
Airway problems 
Reduced lung compliance (as a pneumothorax) 
Patient fighting the ventilator 
Accumulation of water in the tube
Kinking of tube 

35. Modes of PPV Volume Ventilation Pressure Ventilation
Predetermined tidal volume (TV) is delivered with each inspiration
Tidal volume (TV) is consistent, airway pressures will vary
Pressure Ventilation
Predetermined peak inspiratory pressure
Tidal volume (TV) will vary, airway pressures will be consistent

36. Ventilator settings of Modes (Table 66-12 p.1761)
Volume Modes
CMV; AC; SIMV
Predetermined tidal volume (TV) is delivered with each inspiration
Tidal volume (TV) is consistent, airway pressures will vary
Pressure Modes
PSV; PC-IRV
Predetermined peak inspiratory pressure
Tidal volume (TV) will vary, airway pressures will be consistent
Other Modes
PEEP and CPAP

37. Ventilator settings- SIMV and IMV

38. Ventilator settings- Other modes
Positive End-Expiratory Pressure
Positive pressure is maintained at the end of expiration
Pressure at end expiration keeps alveoli from collapsing, improving functional residual capacity (FRC)
Used with other modes on the ventilator
Purpose is to improve oxygenation while limiting risk of O2 toxicity
Used to treat ARDS

39. PEEP

40. Ventilator settings- other modes
Continuous Positive Airway
Similar to PEEP
However, pressure in CPAP is delivered continuously
Prevents airway pressure from falling to zero
Measured in cm H20
Can be administered noninvasively (by mask) or through ETube or TTube
Used in treatment of obstructive sleep apnea

41. Complications of Positive Pressure Mechanical ventilation
Cardiovascular: decreased CO; inc intrathoracic pressure
Pulmonary: Barotrauma; Volutrauma; alveolar hypoventilation/hyperventilation; ventilator-associated pneumonia
Sodium and water imbalance
Neurological: impaired cerebral bl flow>IICP
Gastrointestional: stress ulcer/GI bleed; gas; constipation
Musculoskeletal: dec muscle tone; contractures; footdrop; pressure ulcers from BR
Psychosocial: physical & emotional stress; fight vent

42. Nursing Care for complications
Neurological – elevate head of bed, keep body in proper alignment
Respiratory – monitor cuff inflation, vent settings, ABG’s, for hyperventilation, hypoxemia
Cardiovascular – monitor NIBP and arterial pressures, CO, capillary refill, HR & rhythm
Gastrointestinal – set up schedule for BM, admin laxatives, PPI, admin tube feedings
Musculoskeletal – passive & active ROM, turn q2h, keep body in proper alignment

43. Psychological needs- Need for information; regain control; to hope; to trust
Involve in discision making, medication for sedation (proplfol), analgesia (fentanyl), neuromuscular blocking agents (Nimbex)

44. Other problems when on mechanical ventilation
Machine disconnection or malfunction
Nutrition needs
Weaning from ventilator/ extubation
Spontanenous breathing trial (SBT) Hospital protocol
Document progress
Table p readiness/assessment

45. Exhaled C02 (ETC02) normal 35-45
Used when trying to wean patient from a ventilator

46. Nursing assessment specific to Respiratory Failure
Assess both airway and lungs- note picture to right
Refer to hypoxic and hypercapnic respiratory failure symptoms
Table 68-4 p. 1806
Subjective data
Objective data

47. Cyanosis

49. Relevant Nursing Problems related to Respiratory Failure
Prevention of acute respiratory failure
Nursing Care Plans (p )
Gerontology considerations
Nursing Care Plans Mechanical ventilation (NCP 66-1 p.1754)
Suctioning procedure and oral care (p )

50. Acute Respiratory Distress Syndrome ARDS
Sudden progressive form of acute respiratory failure
Alveolar capillary membrane becomes damaged and more permeable to intravascular fluid
Results in noncardiac pulmonary edema and progressive refractory hypoxemia
ARDS is NOT primary!
Follows various pulmonary or systemic conditions
Sepsis is the most common cause

52. Pathophysiology of ARDS

53. Phases of ARDS Injury or Exudate Phase
Occurs hrs post direct or indirect inj
Systemic inflammatory response and damage to the alveolar-capillary membrane.
Increased capillary permeability
Fluid enters the alveoli
Dilutes and deactivates surfactant
Alveoli stiffen and collapse
Interstitial, alveolar edema & atelectasis> noncardiogenic pulmonary edema
Hypoxemia becomes refractory

54. Phases of ARDS Reparative or proliferative Phase
1-2 wks post initial insult
Regeneration lung tissue may occur
Hyaline membrane forms> CO2 cannot diffuse across> respiratory acidosis
Phase complete when diseased lung dense, fibrous tissue

55. Phases of ARDS Fibrotic phase
2-3wks post insult
Chronic or late phase
Diffuse scarring and fibrosis>decease lung compliance
Dec surface area gas exchange> hypoxemia continues> pulmonary hypertension
Metabolic acidosis can occur> MOSD> death

56. Surfactant keeping alveoli open Fibrotic lung

58. Clinical progression of ARDS
Insidious onset- sym dev hrs post initial insult (direct or indirect lung injury)
Course determined by nature of initial injury, extent & severity of coexisting disease, and pulmonary complications
50% who develop ARDS die- even with aggressive treatment

59. Clinical manifestations of ARDS
Progressive refractory hypoxemia> Hallmark sign
Noncardiac pulmonary edema
Early symptoms- labored R- dyspnea, tachypnea, anxiety/restless, dry-nonproductive cough
Later symptoms- cyanosis, adventitious breath sounds, use of accessory muscles with retractions and decreased mental status

60. Diagnosis of ARDS ABG’s> refractory hypoxemia
Chest X-ray infiltrates> white out/snow storm. Note progression picture to right
Pulmonary artery wedge 18 mm Hg & no evidence of heart failure
Identification of a predisposing condition for ARDS within 48 hrs of clinical manifestations

61. Complications of ARDS Hospital-acquired pneumonia Barotrauma
Volu-pressure trauma
Physiologic stress ulcer
Renal failure

62. Collaborative Care for ARDS Respiratory therapy & medical support
Oxygen
Mechanical ventilation- main treatment
Positioning strategies
Proning
CLRT-lateral rotation bed
Maintenance of CO & tissue perfusion (fluids)
Maintenance of nutrition & fluid balance
Treat underlying cause

63. Prone Device No benefit in mortality Prone positioning
With position change to prone, previously nondependent air-filled alveoli become dependent, perfusion becomes greater to air-filled alveoli opposed to previously fluid-filled dependent alveoli, thereby improving ventilation-perfusion matching.
No benefit in mortality

64. Rotoprone bed

65. Benefits to Proning >

66. Nursing assessment specific to ARDS & Relevant nursing problems R/T ARDS
Refer to respiratory failure assessment
Assess for clinical progression and clinical manifestations as stated above
Nursing care plans- refer to resp failure
Goals for recovery from ARDS
PaO2 within normal limits on room air
SaO2 greater 90%
Patent airway
Lungs clear on auscultation