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

2. Respiratory Failure- outline
Resp volume/capacity and definition Resp failure
Causes/predisposing factors
Classification
Hypoxemic (causes/mechanisms/s&s)
Hypercapic (causes/s&s)
Dx tests Rx
RT/artifical airways/mechanical vent/drugs/medical/nutrition
Nursing (assessment/Nursing Dx- Plan)

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

4. Resp Failure:one or both exchanging systems is inadequate (air to lung or lung to blood)

5. Blood Supply to Lung

6. Respiratory Failure Not a disease process, sign of severe dysfunction
Predisposing Factors (Lewis 1746 Table 68-2)
Airways/alveoli
CNS
Chest wall
Neuromuscular
Commonly defined in terms of ABG’s:
PO2 of less than 60 mmHg
PCO2 greater than 45 mmHg
Arterial pH of less than 7.35

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)

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 such as pulmonary fibrosis; ARDS

13. Hypoxemic Respiratory Failure Mechanisms may lead to Hypoxemia:
Clinical manifestations of hypoxemia
Specific: Respiratory:
Nonspecific: Cerebral, cardiac, other
Treatment: treat cause, O2 and mechanical ventilation

14. Hypercapic Respiratory Failure
Ventatory failure: Inability of the respiratory system to ventilate out sufficient CO2 to maintain normal PaCO2
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 include disorders that compromise lung ventilation and CO2 removal- Lewis Table 68-1 (airways/alveoli, CNS, chest wall, neuromuscular)
Clinical manifestations: specific respiratory, nonspecific of cerebral, cardiac, neuromuscular
Treatment: adeq O2, airway, meds, treat underlying cause, nutrition

15. 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

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

17. 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

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

19. Endotracheal tube

20. Taping and inline suctioning of an endotracheal tube

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

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

23. Independent Lung Ventilation

24. Collaborative Care: Mechanical Ventilation
Provide adeq gas exchange
Criteria to put on vent
RR > 35-45
pCO2 >45
pO2 <50
Types- Positive, Neg
Settings- Table 66-10
Modes- Table 66-12

25. Types: Negative pressure ventilator

26. Types: Positive pressure mechanical ventilation with endotracheal tube (PPV) on left and noninvasive mask on right (CPAP)

27. Ventilator settings of Modes of PPV (Table 66-12 p.1706)
Volume Modes
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

28. Ventilator settings: PEEP SIMV

29. 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
Lewis 1705 Table 66-11

30. Low Pressure High 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 

31. Complications/Nursing Care 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

32. 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

33. 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. 1751
Subjective data
Objective data

34. Relevant Nursing Problems related to Respiratory Failure
Prevention of acute respiratory failure
Nursing Care Plans
Gerontology considerations
Nursing Care Plans Mechanical ventilation
Suctioning procedure and oral care (p )

35. ADRS- outline Normal patho/Definition Causes/predisposing factors
Phases/patho
Injury/exudate
Reparative/poliferation
Fibrotic
Clinical progression/s&s/chest X-ray
Complications Rx
RT-vent & proning-CLRT
Medical support- monitor CO/tissue perfusion & nutrition/fluids
Nursing (assessment/Nursing Dx-Plan)

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

38. Pathophysiology of ARDS

39. Surfactant keeping alveoli open Fibrotic lung

40. 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

41. 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

42. 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

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

44. 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

45. Rotoprone bed

46. Benefits to Proning >

47. 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