Setup of Respiratory Circuits for bubble CPAP

Christopher Thornton, RT

Bubble CPAP Setup

A bubble CPAP circuit should be ready in the neonatal ICU at all times in case of an unexpected delivery of an infant who may need respiratory support. Below is instruction on how to assemble the circuit and what components are needed. To setup a bubble CPAP respiratory circuit, the following items are required:
  1. Oxygen and Air sources
  2. Blender and Flow meter
  3. Humidifier
  4. Inspiratory & Expiratory tubing
  5. Proper elbow connectors and adaptors
  6. Bubbler bottle, measuring tape and adhesive tape

Oxygen and air sources

Oxygen and air sources provide gas flow that constitute the gas mixture delivered to the infant on Bubble CPAP.
  1. Securely, connect air and oxygen sources to the blender

Blender and Flow meter

Setup of Respiratory Circuits for bubble CPAP  width= Air/oxygen source and blender The blender controls how much FiO2 is delivered to the infant and controls the flow in liters per min.
  1. Adjust Flow meter between 5-7 liters of gas mixture per min
  2. Adjust FiO2 to keep saturation between 87-93% or as per MD instructions


The Humidifier filters gas source, provides warmth and humidity to the gas mixture and provides access to the oxygen analyzer.
  1. Items needed to set the Humidifier
    • Oxygen Barb ¾’’ O.D
    • Adapter, Trach T 22mm
    • Bacterial/ Viral Filter
    • Airlife Cuff Connector - 22 mm I.D.
    • Humidifier Chamber
  2. Attach the following pieces from top to bottom as follow:Setup of Respiratory Circuits for bubble CPAP Humidifier and connections
    • Oxygen Barb to Adapter Trach ‘T’
    • Adapter Trach ‘T’ to Filter
    • Filter to Airlife Cuff Connector
    • Insert Cuff connector into Humidifier Chamber

Inspiratory & Expiratory Tubing

Setup of Respiratory Circuits for bubble CPAP Respiratory tubes The inspiratory and expiratory tubes deliver gas mixture to and from the infant
  1. The blue tube is usually connected as the ‘Inspiratory side’ to deliver gas mixture from Humidifier to the infant.
  2. Attach one end of the blue tube to the Humidifier and the other end to one side of the nasal prongs
  3. The white tube is usually connected as the ‘Expiratory side’ to move gas mixture from the infant to the Bubble Bottle.
  4. Attach one end of the white tube to the other end of the nasal prongs. The other end of the white tube will be under a water seal in the bubbler

Bubble Bottle/Bubbler

The bubble bottle or the bubbler is the part where the expiratory tubing end under water surface to create the desired pressure within the Buble CPAP circuit.
  1. Items needed to set the BubblerSetup of Respiratory Circuits for bubble CPAP  width=
    • Sterile water Bottle or 0.25% Acetic Acid Bottle
    • Mask Intubation Adapter (15mm X 22mm)
    • Silicone Flex-adapter
    • Measuring tape (cut from 0 to 8cm)
    • Capillary Tube
  2. Attach the following pieces as follow:
    • Attach the Measuring Tape (8cm) to the Bottle starting from the bottom (Zero up)
    • Attach the Capillary Tube to the Mask Intubation Adapter
    • Thread the bottom of the Capillary Tube through the Silicone Flex-adapter and push half way up and over the Mask Intubation Adapter
    • Place the Capillary Assembly in the Bottle top
    • Empty Acetic Acid to zero level
    • Cut the Gas escape hole in the Bottle
    • Connect it to the Expiratory Tubing
    • Adjust the Capillary Tube depth to the desired bCPAP PEEP level (5-6 cmH2O)


“Not bubbling” equals a LEAK
  1. #1 leak is the babies mouth
  2. Connections are not tight
  3. CPAP Prongs are too small
  4. Check tubing connections starting at Blender to Bubble Bottle for escaping gas