Special Procedures

Fred Hill, MA, RRT

Surfactant Replacement

Composition• Phospholipids (90%)

• phosphatidylcholine (PC) (85%) - dipalmitoyl phosphatidylcholine (DPPC) (60%)

• Phosphatidylglycerol (PG)• Phosphatidylinositol (PI)

• Cholesterol• Proteins (5-10%): SP-A, SP-B, SP-C, SP-D

Surfactant ReplacementIndications

• Prophylactic administration (high risk for developing RDS)– <32 weeks gestational age– <1300 grams– L/S ratio <2:1– Absence of PG

• Therapeutic (rescue) administration– ↑WOB (grunting, retractions, nasal flaring)– ↑ O2 requirements– RDS on CXR

Surfactant Replacement

Types of Surfactant• Exosurf (colfosceril palmitate): synthetic, 5

ml/kg• Survanta (beractant): calf lung, 4 ml/kg• Infasurf (calfactant): calf lung, 3 ml/kg• Curosurf (poractant alfa): pig lung, 2.5

ml/kg

Surfactant ReplacementAdverse Effects

• Bradycardia, desaturation• ETT reflux, ETT obstruction• Barotrauma

Benefit• Decreased mortality rates• Decreased morbidity rates, reduction in:

– Severity of RDS– Pulmonary air leaks– Incidence of BPD

High –Frequency Ventilation

Introduction• Delivery of small tidal volumes at very

high rates (usually >150/min.)• Rates may be expressed in hertz (Hz)

(1 Hz = 60/min.)• Amplitude = ΔP, determines PCO2

• Mean airway pressure determines PO2

High –Frequency Ventilation

Indications• Respiratory failure unresponsive to

conventional methods• Pulmonary air leaks• Congenital diaphragmatic hernia

High –Frequency Ventilation

Hazards• Gas trapping & hyperinflation• Necrotizing tracheobronchitis

(especially with HFJV)• Chest assessment is difficult• Obstruction• Malposition of ETT

High –Frequency Ventilation

Types• High-frequency positive pressure

ventilation (HFPPV)• High-frequency jet ventilation (HFJV)• High-frequency Oscillatory Ventilation

(HFOV)

High –Frequency Ventilation

High-Frequency Positive Pressure Ventilation (HFPPV)

• 60 to 150 bpm• Tidal volume exceeds dead space• Possible advantages:

–↓ pneumothoraces–↓ asynchrony with ventilator

High –Frequency Ventilation

High-Frequency Jet Ventilation (HFJV)Bunnell Life Pulse High Frequency Ventilator

High –Frequency VentilationHigh-Frequency Jet Ventilation (HFJV)

• 240-660 bpm• Passive exhalation• Requires special ETT or adapter• In tandem with conventional ventilator

– Occasional sighs– PEEP– Continuous gas flow for entrainment

High –Frequency Ventilation

High-Frequency Oscillatory Ventilation (HFOV)Sensormedics 3100A

High –Frequency Ventilation

High-Frequency Oscillatory Ventilation (HFOV)

• 8 to 30 HZ (480 – 1800)• Active inspiration and exhalation

Inhaled Nitric Oxide

Action

• Causes smooth muscle relaxation in vascular walls of pulmonary vessels

• Improves oxygen delivery due to dilation of vessels in ventilated areas of lung

Inhaled Nitric Oxide

Applications

• PPHN – most important• MAS• RDS• Pneumonia, sepsis• Congenital diaphragmatic hernia

Inhaled Nitric Oxide

Hazards

• Nitrogen dioxide (NO2)• Methemoglobinemia

Inhaled Nitric Oxide

Application

• INOvent Delivery System• 8 – 20 ppm

INOvent

Extracorporeal Membrane Oxygenation (ECMO)

History

• 1950’s: short-term (hours) in open heart surgery

• 1960’s: long-term (days to weeks)• 1971: first use in infants

Extracorporeal Membrane Oxygenation (ECMO)

Exclusion Crtieria• Gestational age <35 weeks• Pre-existing IVH• Significant coagulopathy or uncontrollable bleeding. • No major (>grade 1) intracranial hemorrhage • Irreversible lung injury • Major congenital/chromosomal anomalies or severe encephalopathy • Major cardiac malformation • Mechanical Ventilation : >7days • Cardiac arrest other than immediately at birth

Extracorporeal Membrane Oxygenation (ECMO)

Inclusion Criteria• 80% mortality risk if no ECMO intervention• Oxygenation Index (OI)>40: OI =(Mean Airway Pressure [cmH20] x

FiO2 x 100) which in turn is divided by the Post ductal PaO2 [mmHg] • OI = Paw x FIO2 x 100 PaO2

• Gestational Age >35 weeks • Weight >2 kgs • Reversible lung disease • No major (>grade 1) intra-cranial hemorrhage • No lethal congenital abnormalities

Extracorporeal Membrane Oxygenation (ECMO)

Mechanisms of Bypass• Venoarterial: blood drawn from right atrium

via right internal jugular vein, returned to the aortic arch via right common carotid artery– Takes over function of heart and lungs

• Venovenous: blood drawn from right atrium via right internal jugular vein, returned to right atrium via femoral vein– Takes over function of lungs

Extracorporeal Membrane Oxygenation (ECMO)

Extracorporeal Membrane Oxygenation (ECMO)

Advantages of Venovenous ECLS

• Sparing of carotid artery• Preservation of pulsatile flow• Normal pulmonary blood flow• Perfusion of lungs with oxygenated blood• Perfusion of coronaries with oxygenated blood• Avoidance of infusion of possible emboli into arterial

circulation• Central venous pressure accurate• Selective limb perfusion does not occur

Disadvantages of Venovenous ECLS

• No cardiac support• Lower systemic PaO2

• Recirculation issues

Advantages of Venoarterial ECLS

• Provides cardiac support• Excellent gas exchange• Rapid stabilization

Disadvantages of Venoarterial ECLS

• Carotid artery ligation• Nonpulsatile flow• Reduced pulmonary blood flow• Lower myocardial oxygen delivery• Direct infusion of possible emboli into

arterial circulation• Central venous pressure inaccurate

Extracorporeal Membrane Oxygenation (ECMO)

Components of ECMO Circuit

• Venous blood drainage reservoir• Blood roller pump• Membrane oxygenator• Heat exchanger

Extracorporeal Membrane Oxygenation (ECMO)

Physiologic Complications• Bleeding• Volume problems• Blood pressure problems• Hematologic problems (anemia,

leukopenia, thrombocytopenia)• Infection

Extracorporeal Membrane Oxygenation (ECMO)

Technical Complications

• Pump failure• Rupture of tubing• Membrane failure• Cannula problems• Other mechanical failures

Extracorporeal Membrane Oxygenation (ECMO)

Overview

• Early method of rescue• Less important today with advent of

SRT, HFOV, and iNO• Still an important life support option in

some centers