Acute Respiratory failure in children Rattapon Uppala, MD. Department of Pediatrics, Faculty of Medicine, KKU

Classification Type I : Hypoxemic respiratory failure Type II : Hypercapnic respiratory failure

Type I Type II

Causes of respiratory failure

Criteria for Diagnosis Clinical criteria Physiologic criteria ↓ or absent respiratory breath sound Severe inspiratory retraction Cyanosis in 40% O2 ↓ Level of consciousness Poor skeletal muscle tone PaCO2 > 65 mm Hg PaO2 < 100 mm Hg in 50% O2 Acute respiratory failure = 3 Clinical + 1 Physiologic Raphaely R. 1981

Acute respiratory failure Clinical manifestations Hypoxemia - tachycardia, tachypnea, sweating, restlessness, hypotension CO2 retention – headache, confusion, coma Abnormal respiratory signs – stridor, adventitious sounds

Acute respiratory failure Ventilatory failure: CO2 retention - Disease of brain & spinal cord - Disease of peripheral nerve, muscle - Drug overdose - etc

Acute respiratory failure Oxygenation failure: hypoxemia, low PaO2 - Upper airway obstruction croup, laryngeal edema, etc - Small airway diseases acute bronchiolitis, asthma, etc - Parenchymal diseases ARDS – pneumonia, near-drowning, etc

Respiratory assessment Spontaneous respiration Respiratory rate

Respiratory assessment Respiratory rate Age 0-2 month: >60/min Age 2 mo – 1 year: >50/min Age 1-5 years: >40/min

Respiratory assessment Spontaneous respiration Respiratory rate Chest movement Chest retraction Breath sounds Upper/lower airway obstruction: stridor, wheezing

Respiratory assessment Spontaneous respiration Respiratory rate Chest movement Chest retraction Breath sounds Upper/lower airway obstruction: stridor, wheezing Cynaosis

Respiratory assessment Assessment and plan for respiratory management Inadequate ventilation or severe upper airway obstruction: intubation and MV Adequate ventilation but inadequate gas exchange: oxygenation

Respiratory assessment Gas exchange assessment Arterial blood gases Ventilation (PaCO2), oxygenation (PaO2), pH Pulse oximetry Oxygenation (SpO2)

Respiratory management

Type I Type II

Upper airway obstruction: stridor lower airway diseases & lung Respiratory distress Upper airway obstruction: stridor lower airway diseases & lung Severe retraction Not severe Endotracheal intubation Oxygenation Improve Not improve O2 via T-piece Mechanical ventilation Find out and treat definite causes

Management RS diseases Croup: Definite: Dexamethasone 0.3-0.6 mg/kg single dose oral or IM RS: assess severity – CROUP score Mild - O2 therapy Moderate – epinephrine nebulization with O2 therapy Severe – endotracheal intubation + O2 therapy

Management RS diseases Acute bronchiolitis: Definite: No definite treatment RS: O2 therapy Optional - bronchodilator vs dexamethasone

Management RS diseases Asthma: Definite: bronchodilator – 2 agonist systemic corticosteroid – hydrocortisone/prednisolone RS: not severe – O2 therapy severe – mechanical ventilation

Management RS diseases Pneumonia: Definite: virus – no specific bacteria – antibiotics RS: not very severe – O2 therapy severe – mechanical ventilation

Management Treat primary insult Adequate tissue oxygenation NIV Mechanical ventilation Prevent complications

Management Treat primary insult Adequate tissue oxygenation NIV Mechanical ventilation Prevent complications

Inhalation therapy Oxygen therapy

Normal airway Warm gas to 34oC Air gas + humidity

Diffusion

Gas transport to the periphery

Oxygen source

เครื่องทำความชื้น Humidifier Nebulizer Pass over Bubble Heated Jet Ultrasonic Hand medical Humidity Aerosol

น้ำที่อยู่ในสภาวะของก๊าซ (vapor) Aerosol (ฝอยละออง) Humidity & Aerosol Humidity (ไอน้ำ) น้ำที่อยู่ในสภาวะของก๊าซ (vapor) Aerosol (ฝอยละออง) น้ำหรือของเหลวที่แขวนลอยอยู่ในอากาศหรือก๊าซ (liquid particle) Aerosolization = nebulization

Humidifier Unheated humidifier Heated humidifier Bubble with mechanical ventilator

Bubble humidifier ท่อนำก๊าซ

Heated humidifier

Nebulizer Jet nebulizer Untrasonic nebulizer Medical nebulizer Hand held Pressurized metered dose inhaler(pMDI) Dry powder inhaler (DPI)

Jet nebulizer ท่อนำก๊าซ Corrugated tube High flow

Jet nebulizer

Ultrasonic nebulizer

Medical nebulizer

Oxygen therapy Cannula Simple mask Mask with reservoir bag Hood or box T-piece Mechanical ventilator

O2 Cannula Bubble humidifier O2 1 LPM ~ 4%

O2 Mask / with reservior Bubble humidifier Simple mask 5-10 LMP ~ 35-50% Reservoir bag 6-10 LPM ~ 60-90%

Tracheotomy mask Corrugated tube

O2 Box/Hood

O2 T-piece

Endotracheal intubation Heated humidifier

Oxygen dissociation curve SaO2 PaO2 SaO2 60 90 50 80 40 70 PaO2

Gas transport to the periphery

Complication of O2 therapy Retinopathy of prematurity (ROP) Bronchopulmonary dysplasis (BPD) Absorptive atelectasis Apnea in COPD patient

Management Treat primary insult Adequate tissue oxygenation NIV Mechanical ventilation Prevent complications

NIV High flow nasal cannula CPAP BiPAP

Mechanical ventilation Low tidal volume Precaution if high FiO2 for more than 24 hour Lung recruitment strategy in ARDS High PEEP in ARDS Considered HFOV

ARDS

Berlin’s definitions Acute onset within 7 days Bilateral opacities PF ratio less than 300 <300 = mild <200 = moderate <100 = severe Exclude volume overload

Primary insult to lungs Pathophysiology Primary insult to lungs Direct injury : aspiration เช่น near-drowning, gastric, hydrocarbon, etc Indirect injury : sepsis, brain edema, etc Alveolar-capillary membrane injury

Alveolar-capillary membrane injury Primary insult Alveolar-capillary membrane injury Inflammatory cytokines Vascular permeability Obliteration of microcirculation Surfactant def Dead space ventilation Atelectasis Cell+protein leak Intrapulmonary shunt, pulmary hypertension

Diagnosis Bilateral pulmonary infiltration No cardiogenic pulmonary edema Severe acute lung injury : shunt - PaO2 / FiO2 < 300 - PaO2 / PAO2 < 0.15 - R.I. (Respiratory Index) R.I. = P(A-a) O2 / PaO2 > 5

Management Treat primary insult Adequate tissue oxygenation NIV Mechanical ventilation: high PEEP with recruitment protocol Prevent complications

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