Respiratory FailureAbdul-Aziz Ontok, Fritzie Rasonable, April Suzette Exile

TOPIC OUTLINE Definition Epidemiology Classification Approach to the Patient with

Respiratory Failure Clinical Evaluation by Physiologic

Principles Specific Respiratory Failure Syndromes Mechanical Ventilation

DEFINITION Failure of gas exchange due to inadequate

function of one or more essential components of the respiratory system

Manifest as: Hypoxemia – PO2 <60 mmHg (↓ O2) Hypercarbia – PCO2 >45 mmHg (↑ CO2) Combination of the two*

As respiratory demand exceeds functional capacity of the respiratory system, respiratory failure evolves

EPIDEMIOLOGY Common diagnosis among patients in ICU

Associated with poor prognosis

137:100,000 ind. or 360,000/year (U.S.)

36% of these individuals fail to survive

Incidence and Mortality increase with age and presence of co-morbid conditions

CLASSIFICATION

1. By Pathophysiologic Derrangement

2. By its Acuity

3. By Physiologic Deficit

Pathophysio. Derangement Type I – alveolar floodingoPulmonary edema• Heart failure• Intravascular volume overload• Acute lung injury

ARDSoPneumoniaoAlveolar hemorrhage

Pathophysio. Derangement Type I – alveolar flooding Type II – alveolar hypoventilationo Impaired CNS drive to breatheo Impaired strength of neuromuscular

function in the respiratory systemo Increased loads on the respiratory

system

Pathophysio. Derangement Type I – alveolar flooding Type II – alveolar hypoventilationo Impaired CNS drive to breathe• Drug overdose• Sleep-disordered breathing• Hypothyroidism

Pathophysio. Derangement Type I – alveolar flooding Type II – alveolar hypoventilationo Impaired CNS drive to breatheo Impaired strength of neuromuscular

function in the respiratory system• Impaired neuromuscular transmission

MG, Guillain-Barre Sx, Phrenic nerve injury

• Respiratory muscle weaknessElectrolyte derangements

Pathophysio. Derangement Type I – alveolar flooding Type II – alveolar hypoventilationo Impaired CNS drive to breatheo Impaired strength of neuromuscular

function in the respiratory systemo Increased loads on the resp. system• Resistive loads – bronchospasm• Reduced lung compliance – atelectasis• Reduced wall compliance - pneumothorax• Increased minute vent. req. – embolus

Pathophysio. Derangement Type I – alveolar flooding Type II – alveolar hypoventilation Type III – lung atelectasis in the

perioperative period

Pathophysio. Derangement Type I – alveolar flooding Type II – alveolar hypoventilation Type III – lung atelectasis in the

perioperative period Type IV – hypoperfusion of respiratory

muscles in patients in shock

CLASSIFICATION

1. By Pathophysiologic Derrangement

2. By its Acuity

3. By Physiologic Deficit

Acuity Acute Respiratory Failureo sudden, catastrophic event leads to life-

threatening respiratory insufficiency Chronic Respiratory Failureo gradual worsening of respiratory

function that leads to progressive impairment of gas exchange

ometabolic effects are partially compensated by adaptations in other systems

CLASSIFICATION

1. By Pathophysiologic Derrangement

2. By its Acuity

3. By Physiologic Deficit

Physiologic Deficit Nervous System – controller dysfunction Musculature – pump dysfunction Airways – airway dysfunction Alveolar Units – alveolar dysfunction Vasculature – pulm. vascular dysfunction

Failure of any one of these components can lead to respiratory failure

Physiologic Deficit Nervous System – controller dysfunction• Sedative medications• Chronic obstructive lung disease• Hypothermia post operatively• Brainstem stroke

Musculature – pump dysfunction Airways – airway dysfunction Alveolar Units – alveolar dysfunction Vasculature – pulm. vascular dysfunction

Physiologic Deficit Nervous System – controller dysfunction Musculature – pump dysfunction• Botulism• Myasthenia Gravis• Guillain-Barre syndrome• Postoperative pain

Airways – airway dysfunction Alveolar Units – alveolar dysfunction Vasculature – pulm. vascular dysfunction

Physiologic Deficit Nervous System – controller dysfunction Musculature – pump dysfunction Airways – airway dysfunction• Asthma• Emphysema• Bronchitis• Endobronchial mass/stricture

Alveolar Units – alveolar dysfunction Vasculature – pulm. vascular dysfunction

Physiologic Deficit Nervous System – controller dysfunction Musculature – pump dysfunction Airways – airway dysfunction Alveolar Units – alveolar dysfunction• Pneumonia• Pulmonary edema• Pulmonary hemorrhage• ARDS

Vasculature – pulm. vascular dysfunction

Physiologic Deficit Nervous System – controller dysfunction Musculature – pump dysfunction Airways – airway dysfunction Alveolar Units – alveolar dysfunction Vasculature – pulm. vascular dysfunction• Acute pulmonary embolus• Pulmonary hypertension• Arteriovenous malformation

APPROACH TO THE PATIENT1. Determination of upper airway patency

Unconscious (occlusion of the tongue) Head tilt-chin lift maneuver

Unable to dislodge foreign object Subdiaphragmatic thrust

Suction secretions/vomitus Secure airway with endotracheal tube if

necessary Perform tracheostomy/cricothyroidotomy

if airway cannot be secured with ETT

APPROACH TO THE PATIENT2. Measurement of respiratory rate3. Observation of the depth and pattern of

respiration simultaneously note signs of respiratory

distress: alar flaringpursed-lip breathinguse of accessory muscles

4. Palpation and Auscultation over each hemithorax

APPROACH TO THE PATIENT5. Supplement findings with ABG

measurement• Oximetry provides rapid way to determine blood

oxygen content but does not provide information regarding alveolar ventilation and PCO2; do ABG

6. Implement initial therapy before specific etiology is diagnosed and treated• Supplemental oxygen might be all that is needed• Artificial ventilation if patient is in distress

CLINICAL EVALUATIONDYSFUNCTION TEST FINDINGS IN DYSFUNCTION

Controller Respiratory rate <12/min in presence of hypoxia or hypercarbia and acidemia

CLINICAL EVALUATIONDYSFUNCTION TEST FINDINGS IN DYSFUNCTION

Controller Respiratory rate <12/min in presence of hypoxia or hypercarbia and acidemia

Pump Inspection,Vital Capacity, Inspiratory Force

Presence of paradoxical respiratory motions VC < 10 mL/kg IF < -20 cm water

CLINICAL EVALUATIONDYSFUNCTION TEST FINDINGS IN DYSFUNCTION

Controller Respiratory rate <12/min in presence of hypoxia or hypercarbia and acidemia

Pump Inspection,Vital Capacity, Inspiratory Force

Presence of paradoxical respiratory motionsVC < 10 mL/kgIF < -20 cm water

Airway Auscultation Presence of wheezing or rhonchi

CLINICAL EVALUATIONDYSFUNCTION TEST FINDINGS IN DYSFUNCTION

Controller Respiratory rate <12/min in presence of hypoxia or hypercarbia and acidemia

Pump Inspection,Vital Capacity, Inspiratory Force

Presence of paradoxical respiratory motionsVC < 10 mL/kgIF < -20 cm water

Airway Auscultation Presence of wheezing or rhonchi

Alveolar Chest XR Alveolar infiltrates

CLINICAL EVALUATIONDYSFUNCTION TEST FINDINGS IN DYSFUNCTION

Controller Respiratory rate <12/min in presence of hypoxia or hypercarbia and acidemia

Pump Inspection,Vital Capacity, Inspiratory Force

Presence of paradoxical respiratory motionsVC < 10 mL/kgIF < -20 cm water

Airway Auscultation Presence of wheezing or rhonchi

Alveolar Chest XR Alveolar infiltrates

Pulm. Vascular JVP, ECG JVD, RBBB