Table of Contents

1. Introduction to ventilator management and the different types of ventilators available in the NICU
2. "Volume ventilators"
3. High frequency ventilators
4. "Pressure ventilators"
5. Ventilator modes, terms and types
6. Specific types of ventilators and their functions
1. Drager Babylog 8000
2. Sensormedics 3100A
3. Siemens Servo 900c
4. Siemens Servo 300

Introduction
There are three fundamentally different modes of ventilation available in the NICU: "pressure ventilators", "volume ventilators",, and high frequency ventilators. They all serve to support adequate ventilation and oxygenation, but each has it's own particular niche.
Ventilation (CO2 removal) is a function of minute ventilation which is respiratory rate (RR) multiplied by tidal volume (Vt).
MINUTE VENTILATION = RATE x TIDAL VOLUME

Arterial Oxygenation improves when either the fraction of inspired oxygen concentration (FiO2) and/or mean airway pressure (MAP) are increased.

The first step in managing a patient on a ventilator is to choose appropriate goals for ventilation and oxygenation (i.e. blood gases). These goals depend on the patient's disease state. An otherwise healthy term infant intubated for choanal atresia might have as a goal pH = 7.40, PaCO2 = 40, PaO2 = 60. In a small preterm infant (<1000g), to minimize lung injury due to mechanical ventilation, a strategy of mild permissive hypercapnea may be followed. In a patient with severe chronic lung disease gases with PaCO2 of 60-65 torr and SaO2 >88% may be acceptable. In contrast, a patient with persistent pulmonary hypertension of the newborn might have as a goal pH>7.45, PaCO2<30, PaO2>100 in an attempt to attenuate hypoxic pulmonary vasoconstriction.
Ventilation goals can be a range of pH values and/or a range of PaCO2 values. Extreme acidosis (pH<7.10) is to be avoided but otherwise mild acidosis alone appears to be relatively well tolerated. Of greater concern are wide swings in PaCO2 which can have significant effects on cerebral blood flow. Also of concern is identifying and, if appropriate, treating the underlying cause of the acidosis. Ventilation can best be monitored using arterial blood gases. Capillary blood gases (and even more so venous) tend to give low values for pH (~0.05-0.1 lower depending on perfusion). The difference between arterial and capillary or venous pH is variable over time and between patients. As an estimate of ventilation, it does not work well in older infants with BPD, infants with hydrops, and other conditions that impair transcutaneous passage of capillary gas. If using a conventional ventilator (not High Frequency), end tidal CO2 monitoring (capnography) is another valuable non-invasive method of

Referrence: http://depts.washington.edu/nicuweb/NICU-WEB/vents.stm