5.2 Ventilation Devices: Self-Inflating, Flow-Inflating, and T-Piece

Why Device Literacy Is a Clinical Skill, Not Trivia

When PPV is indicated, the air has to come from something in your hands. Hospitals stock different brands, but NRP expects you to understand three device families: the self-inflating bag, the flow-inflating bag (often called an anesthesia bag), and the T-piece resuscitator. Exam items compare oxygen source needs, PEEP, free-flow oxygen ability, and pressure control. Skills stations expose the same differences in your fingers: a device you do not understand becomes a delay, a leak, or an unnoticed high-pressure breath.

Device choice is usually a unit standard, not a personal preference invented mid-code. Your job is to know the strengths and limitations of whatever is on the warmer—and to practice mask technique that works on all three.

Shared Requirements Before Any Device Works

No resuscitator can overcome a closed airway or a leaking mask. Across devices you still need:

• Correct mask size: covers mouth and nose, rests on the chin, does not cover the eyes
• Sniffing position (neutral for very preterm; avoid overextension)
• A seal created with gentle downward pressure and jaw support—not crushing the face
• Eyes on chest movement and ears on heart rate response
• An oxygen blender (or controlled FiO₂ source) when supplemental oxygen is used, plus a pulse oximeter

If the chest is not moving, the first suspicion is technique or airway—not “wrong brand of bag.” Corrective steps (MR SOPA) in the next chapter assume you already know how your device delivers pressure.

Self-Inflating Bag

How it works

A self-inflating bag re-expands on its own after each squeeze because of the bag’s elastic structure and one-way valves. It can deliver positive-pressure breaths without a compressed gas source. That makes it valuable in transport, power failures, or settings where wall oxygen/air is not yet connected.

Without a gas source and reservoir, however, the infant receives approximately room air (about 21% oxygen) unless the bag is attached to oxygen with an appropriate reservoir system that allows higher FiO₂. Know your unit’s setup: many neonatal bags are used with oxygen and a reservoir so blended or high FiO₂ can be delivered when indicated.

Safety features

Neonatal self-inflating bags should have:

• A pressure-release (pop-off) valve that vents excessive pressure (often around a manufacturer-set limit such as ~30–40 cm H₂O—know that it exists and can sometimes be overridden intentionally only under controlled circumstances per device design and training)
• Ideally an in-line manometer so you can see peak inspiratory pressure rather than guessing by “feel”

Adult bags are inappropriate for newborns: volumes and pressures are wrong. Use neonatal/infant bags only.

PEEP and free-flow oxygen limitations

A plain self-inflating bag does not reliably deliver PEEP unless a PEEP valve is attached and used correctly. Many educational items emphasize that a self-inflating bag without a PEEP valve cannot provide the continuous end-expiratory pressure that helps maintain functional residual capacity.

Free-flow oxygen is also a weak point: you generally cannot deliver reliable free-flow oxygen by simply holding a self-inflating bag near the face the way you can with a flow-inflating bag or T-piece open to flow. Units often keep a separate free-flow oxygen method (mask, tubing, or T-piece in free-flow mode) for the breathing, cyanotic infant who does not need PPV.

Training notes

Self-inflating bags are common and relatively forgiving for intermittent PPV because the bag reinflates even if the mask seal is imperfect—but a poor seal still means poor tidal volume to the baby. The bag may look like it is “working” while the infant receives little ventilation. Always judge success by chest movement and rising heart rate, not by bag motion alone.

Flow-Inflating Bag

How it works

A flow-inflating bag fills only when continuous gas flow is present and the outlet is adequately occluded (by a tight mask seal or a closed control). No compressed gas source means no ventilation—the bag will not inflate. Flow rate and the adjustable outlet control determine how full the bag stays and how pressure builds.

Strengths

• Excellent tactile feedback: experienced providers feel compliance changes
• Can deliver free-flow oxygen when the bag is used with continuous flow near the face (with proper technique)
• Can provide PEEP/CPAP-like continuous pressure when flow and seal are managed correctly
• PIP is controlled by squeeze depth and flow/outlet settings—requires skill

Challenges

• Requires a gas source at all times
• Mask leak deflates the bag and drops pressure—training intensive
• Easy to deliver excessive pressure if the operator squeezes hard without a manometer
• Less “automatic” for occasional users than a T-piece with set pressures

Flow-inflating bags reward deliberate practice. In a crisis, an unpracticed provider may struggle more than with a T-piece or self-inflating bag.

T-Piece Resuscitator

How it works

A T-piece resuscitator is a flow-driven device with controls that set peak inspiratory pressure (PIP) and positive end-expiratory pressure (PEEP). The provider occludes an opening (finger or cap) to deliver an inspiration at the set PIP and releases to allow expiration against the set PEEP. Like the flow-inflating bag, it requires a compressed gas source.

Strengths

• Consistent, controlled PIP breath to breath—reduces wild pressure swings
• Reliable PEEP at a typical starting value near 5 cm H₂O when set appropriately
• Well suited to prolonged PPV and to preterm care where pressure discipline matters
• Can provide free-flow oxygen or continuous positive airway pressure modes depending on setup and training

Challenges

• Dependent on gas supply and correct pre-use check (set PIP/PEEP, confirm pressures on a test lung or occluded circuit per unit protocol)
• If settings are wrong before birth, every breath is wrong until someone notices
• Finger-occlusion timing still must match the 30–60 breaths/min rate

Exam items often identify the T-piece as the device that best delivers set PIP plus reliable PEEP compared with a self-inflating bag lacking a PEEP valve.

Comparison Table (Memorize the Differences)

Choosing and Checking Before Birth

During the equipment check:

1. Identify which device is primary on the warmer.
2. Confirm gas is flowing (for flow-inflating and T-piece).
3. For T-piece: set and verify PIP and PEEP on a test occlusion.
4. For self-inflating bag: confirm pop-off function, manometer if present, correct neonatal bag size, oxygen/reservoir connection as planned.
5. Have multiple mask sizes ready.
6. Know your backup: if the T-piece fails, can you ventilate with a self-inflating bag?

Realistic Device Scenarios

Scenario A. Power and wall gas fail during a power outage drill; infant needs PPV. A self-inflating bag can still deliver room-air breaths; a T-piece without gas cannot.

Scenario B. Team wants consistent PEEP of about 5 cm H₂O and steady PIP for a preterm infant. A T-piece (or flow-inflating bag in skilled hands) is preferred over a self-inflating bag without a PEEP valve.

Scenario C. Provider squeezes a self-inflating bag vigorously; the bag reinflates each time but the chest never moves and HR stays 70. The bag’s motion does not prove ventilation—seal and airway must be fixed (MR SOPA).

Scenario D. Breathing infant needs free-flow oxygen. Holding a self-inflating bag loosely on the face is not the reliable method taught for free-flow; use an appropriate free-flow technique/device.

Bottom Line for the OLA and Skills Day

• Know gas source dependence, PEEP, and free-flow differences cold.
• Prefer devices and settings that deliver controlled pressure when available.
• Never let device brand distract you from mask seal, position, and rate.
• Practice on the device your unit actually uses until occluding, squeezing, or “thumb on the T-piece hole” is automatic under stress.