What is respiratory arrest?

It is the state in which breathing has stopped or become inadequate, although the heart may still be beating.

How is a rescue breath given to an adult?

Pinch the soft part of the nose closed, seal your lips around the casualty's mouth and blow steadily for about one second until the chest rises, then take your mouth away and let the chest fall.

How can a rescuer tell that a rescue breath has been effective?

The casualty's chest is seen to rise as the breath is given and to fall again afterwards.

Why should a rescue breath be blown in steadily rather than forcefully?

Blowing hard raises the pressure so that air is forced into the oesophagus and inflates the stomach, which makes the casualty likely to vomit.

OCR A-Level Biology B H422

The Developing Cell: Cell Division and Cell Differentiation

Topic overview The cell cycle and mitosis Apoptosis in growth and repair Stem cells and cell differentiation

The Developing Individual: Meiosis, Growth and Development

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Gas Exchange in Mammals and Plants

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Gas Exchange in Mammals and Plants

Expired air resuscitation

3 things to know
Components 01, 02 and 03

Overview

Recall questions on why exhaled breath supplies oxygen, opening an airway, giving an effective breath, how the technique differs for a baby, and the devices used instead of mouth-to-mouth.

What you need to know

Answer each one before you reveal it.

Your recallNot started

Process

How is expired air resuscitation given to an adult, how is each breath checked, and what differs for a baby?

Key term

Why can breathing out into a casualty supply them with oxygen?

Key term

How is the airway of an unresponsive adult opened before rescue breaths are given?

Questions from this subtopic

Each one with the model answer underneath.

1
What is respiratory arrest?
Model answer
It is the state in which breathing has stopped or become inadequate, although the heart may still be beating.
2
Why can breathing out into a casualty supply them with oxygen?
Model answer
Only about a quarter of the oxygen breathed in is absorbed, so expired air still contains roughly 16% oxygen, which is enough to oxygenate the casualty's blood.
3
How is the airway of an unresponsive adult opened before rescue breaths are given?
Model answer
Place one hand on the forehead and tilt the head back, then lift the chin with two fingertips, which lifts the tongue clear of the back of the throat.
4
How is a rescue breath given to an adult?
Model answer
Pinch the soft part of the nose closed, seal your lips around the casualty's mouth and blow steadily for about one second until the chest rises, then take your mouth away and let the chest fall.
5
How can a rescuer tell that a rescue breath has been effective?
Model answer
The casualty's chest is seen to rise as the breath is given and to fall again afterwards.
6
Why should a rescue breath be blown in steadily rather than forcefully?
Model answer
Blowing hard raises the pressure so that air is forced into the oesophagus and inflates the stomach, which makes the casualty likely to vomit.

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The Developing Cell: Cell Division and Cell Differentiation

The Developing Individual: Meiosis, Growth and Development

The Development of Species: Evolution and Classification

Cells and Microscopy

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