Respiratory: Respiratory Failure and ARDS

1. Respiratory: Respiratory Failure and ARDS Marnie Quick, RN, MSN, CNRN Revision: Summer 2011

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 1801 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. 1800 Table 68-1)

9. 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 FailureRange 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. Hypoxemic Respiratory FailureMechanisms that may lead to Hypoxemia: 2. 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 FailureMechanisms may lead to Hypoxemia: 3. 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 FailureMechanisms 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 66-11 • 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.1761) • 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: PEEPSIMV

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

30. 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 

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 66-13 p.1767- 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. 1806 • Subjective data • Objective data

34. Relevant Nursing Problems related to Respiratory Failure • Prevention of acute respiratory failure • Nursing Care Plans (p.1807-09) • Gerontology considerations • Nursing Care Plans Mechanical ventilation (NCP 66-1 p.1754) • Suctioning procedure and oral care (p.1757-8)

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 24-48 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 • Assessment • 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