EMT Chapter 10 Airway management, Artificial Ventilation, and Oxygenation

Respiration

The gas exchange process that occurs between the alveoli or cells and the capillaries

Four distinct components of respiration

1) pulmonary ventilation

2) external respiration

3) internal respiration

4) cellular respiration and metabolism

Pulmonary ventilation

the mechanical process of moving air in and out of the lungs

External respiration

the gas exchange process that occurs between the alveoli and the surrounding pulmonary capillaries; serves to oxygenate the blood and eliminate carbon dioxide in the lungs

Internal respiration

cell/capillary gas exchange; is responsible for delivering oxygen to the cells and removing carbon dioxide from the cell

Cellular respiration and metabolism

Breaks down glucose in the presence of oxygen, produces high amounts of energy in the form of ATP, and releases carbon dioxide and water as a by-product

The upper airway

Nasal cavity, Nasopharynx, Oropharynx, Hypopharynx (laryngopharynx), epiglottis, esophagus, trachea, and larynx

Pharynx

Throat

Nasopharynx

Where air from the nasal passages enter

Oropharynx

Where air from the mouth travels to get to the lungs

Importance of keeping a clear pharynx

Obstructions can prevent air from traveling into the lower airways or the substance may be aspirated into the lungs.

The two passageways found at the lower end of the pharynx

The trachea and the esophagus

Larynx

Above the trachea and below the epiglottis; the voice box

Thyroid cartilage

the anterior portion of the larynx; the adams apple

Cricoid cartilage

the inferior portion of the larynx; the only completely circular cartilaginous ring of the upper airway

The lower airway

From the cricoid cartilage to the alveoli

Trachea

The windpipe; the passageway for air entering the lungs

The carina

the point at which the trachea splits into the right and left main stem bronchi

The anterior portion of the trachea

composed of strong C-shaped cartilaginous rings that provide support and structure

The posterior wall of the trachea

Made up of muscle and is not a rigid structure

Bronchi

the two major branches of the trachea; extends from the carina into the lungs

Bronchioles

Smaller sections of the bronchi; lined with smooth muscle and mucous membranes

When the mucous lining of the bronchioles becomes inflamed and swollen

Severely narrows the diameter of the bronchiole and causes lower airway obstruction (as seen in asthma). The narrowing causes an increase in airway resistance inside the bronchiole, which makes it difficult to move air

An increase in airway resistance

Causes the patient to work harder to breathe which may lead to fatigue and failure of the respiratory muscles

Leads to cell hypoxia

ineffective and inadequate ventilation and oxygenation

Alveoli

Tiny air sacs in the lungs

Pulmonary capillaries

a web of thin-walled capillaries that wrap the alveoli; the site of gas exchange

The composition of the lungs

elastic tissue

The pleura

The two layers of connective tissue that surround the lungs

The visceral pleura

the innermost covering of the lung

The parietal pleura

thicker, more elastic layer that adheres to the inner portion of the chest wall

Between the two pleura layer

the pleural space; at negative pressure

Serous fluid

acts as a lubricant to reduce friction in the pleura space

The diaphragm

muscle that separates the chest cavity from the abdominal cavity; major muscle used in breathing; responsible for 60-70% of the effort of ventilation

Ventilation

Passage of air into and out of the lungs; creates pressure changes in the lungs to draw air in and force air out

Inhalation/inspiration

breathing air in

Exhalation/expiration

process of breathing air out

Inhalation mechanics

diaphragm and the external intercostal muscles contract; increases the size of the chest cavity, creating negative pressure inside the chess cavity; active process

Exhalation mechanics

Diaphragm and external intercostal muscles relax; reduced chest cavity size; positive pressure; forces volume of air out of the lungs; passive

Control of Respiration

The respiratory organs do not have the ability to control their function from within the respiratory system; respirations are controlled by the nervous system

The response to an increase level in arterial blood

The chemoreceptors sense the increase and the brainstem sends impulses to the respiratory muscles to increase the rate and depth of respiration

The main stimulus for breathing in healthy people

Carbon dioxide

Hypercarbic drive

What healthy people breath

The difference between COPD people and normal people

In people with COPD the carbon dioxide level in arterial blood is typically chronically elevated as a result of the disease process. Because of the constant high carbon dioxide level the chemoreceptors become relatively insensitive to changes in carbon dioxide. Instead the chemoreceptors in COPD patients tend to rely on oxygen levels in the blood to regulate their breathing.

Why do COPD people breath?

To increase their oxygen levels instead of decrease their Carbon dioxide level

Oxygenation

the process by which the blood and the cells become saturated with oxygen

Internal respiration and external respiration

the process in which fresh oxygen replaces waste carbon dioxide, a gas exchange that takes place between the alveoli and the capillaries in the lungs, and between the capillaries and the cells throughout the body

Hypoxemia

Low oxygen content in arterial blood. Typically occurs from a ventilation-perfusion mismatch

Ventilation-perfusion mismatch

occurs when there is a lack of available oxygenated air in the alveoli even though perfusion (blood flow) to the alveoli is adequate or when the alveoli are adequately oxygenated but perfusion to the alveoli is poor or when there is a combination of both poor ventilation and poor perfusion in the alveolar-capillary structures

Other causes of hypoxemia

inadequate ventilatory drive, anemia, and carbon monoxide poisoning

Hypoxia

inadequacy in the amount of oxygen being delivered to the cells

Different causes of hypoxia

Occluded airway, inadequate breathing, inadequate breathing, inadequate delivery of oxygen to the cells by the blood (hyper fusion or shock), inhalation of toxic gases, lung and airway deceases, etc

Signs of Mild to Moderate Hypoxia

Tachypnea (increased respiratory rate)

Dyspnea (shortness of breath)

Pale, cool, clammy skin (early)

Tachycardia

Elevation in blood pressure

Restlessness and agitation (from hypoxic brain cells)

Disorientation and confusion (from high CO2 levels)

Headache

Signs of Severe Hypoxia

Tachypnea

Dyspnea

Cyanosis

Tachycardia that may lead to dysrhythmias and eventually bradycardia

Severe confusion

Loss of coordination

Sleepy appearance

Head bobbing with droopy eyelids

Slow reaction time

Altered mental status

Seizure

Cyanosis

a bluish gray color, a late sign of hypoxia and may be found in and around several areas including the lips, mouth, nose, fingernail beds

Gas content of the blood entering the capillaries

High oxygen content and a low carbon dioxide content

Causes of disruption in the mechanical process of pulmonary ventilation

•Interruption of the nervous system's control and stimulation of the diaphragm or of the external intercostal muscles

•Structural damage to the thorax may interfere with the bellows action of the chest. This will impede the ability of the thorax to generate pressure changes necessary to draw air into the lungs for inhalation and to allow airflow out of the lungs during exhalation. Pain associated with chest injury, flail chest (two or more ribs fractured in two or more places), rupture or injury to the diaphragm, or compression of the chest wall can reduce the effective bellows action of the chest

•Increased airway resistance will reduce airflow through the respiratory tract and reduce the amount of air in the alveoli. This will make less oxygen available for gas exchange. An increase in airway resistance may occur from bronchoconstriction or from inflammation inside the vessel

•Disruption of airway latency can occur from swell in caused by infection, allergic reaction, or burns; from trauma; from foreign body obstruction; or from loss of muscle tone associated with an altered mental status or unresponsiveness. Reduction or loss of airway latency will reduce the tidal volume, minute ventilation, alveolar ventilation, and volume of gas in the lungs for gas exchange

The mouth and nose of children

The noses and mouths of infants and children are smaller than those of adults; thus it is especially important to keep the nose clear of obstructions

The pharynx of children

The tongue of an infant or child is relatively large in proportion to the size of the mouth.

The trachea and lower airway of children

Narrower, softer, and more flexible than adults. Airway obstructions occur more easily from mucus, pus, blood, secretions, swelling, constriction, and kinking of the trachea with flexion or extension

Chest wall in children

Softer and more pliable than in an adult; leads to greater compliance during ventilation

Patent airway

open airway

Functions and considerations regarding the airway

•the airway and respiratory tract is the conduit that allows air to move from the atmosphere and into the alveoli for gas exchange

•No matter what the patient's condition, the airway must remain patent at all times

•Any obstructions of the airway will result in less air movement, which will lead to some degree of poor gas exchange and potential hypoxia

•The degree of the obstruction will directly affect the amount of air available for gas exchange. The tongue may create only a partial airway obstruction, whereas a piece of food may completely stop airflow

A patient's mental status typically correlates to the status of his airway

An alert, responsive patient who is talking to you in a normal voice has an open airway. A patient with an altered mental status or who is completely unresponsive connote adequately protect his own airway.

Signs of an open airway

1) air can be felt and heard moving in and out of the mouth and nose

2) the patient is speaking in full sentences or with little difficulty

3) the sound of the voice is normal for the patient

Snoring

occurs when the upper airway is partially obstructed by the tongue or by relaxed tissues in the pharynx.

Crowing

sounds like a crow cawing that occurs when the muscles around the larynx spasm and narrow the opening into the trachea, air rushing through the restricted passage causes the sound

Gurgling

sounds like gargling, usually indicates the presence of blood, vomitus, secretions, or other liquid in the airway

Stridor

a harsh, high-pitched sound heard during inspiration, characteristic of a significant upper airway obstruction from swelling in the larynx, may also be heard if a mechanical obstruction by food or other object is presence

Head-tilt, Chin-lift maneuver

no spinal injury

Jaw-thrust maneuver

suspected spinal injury

Standard precaution during suctioning

Protective eyewear, a mask, and gloves. If a patient is known to have TB an N-95 should be worn

Suction Equipment

The device that creates the suction and the catheters

Mounted Suction Devices

On-board the ambulance, should be powerful enough to provide an airflow of >40 lpm and create a vacuum of more than -300 mmHg

Portable Suction Devices

Should be capable of generating -300 mmHg of pressure when the suction hose is clamped. A pressure of -80 to -120 mmHg is generally necessary to provide adequate suction. Can be electric, oxygen, air or hand powered

Hard or rigid catheter

Rigid plastic tube; Yankauer catheter or the tonsil tip. Used to suction the mouth and oropharynx of an unresponsive patient. Only be inserted as far as you can see and no farther than the back of the tongue.

Soft catheter

Flexible tubing; also called the "French" catheter. Used in suctioning the nose and nasopharynx and in other situations where the rigid catheter can not be used. Length should be determined by measuring from the tip of the patient's nose to the tip of the ear

Special considerations when suctioning

•If the patient has secretions or vomitus that cannot be removed quickly and easily by suctioning, the patient should be log rolled onto his side and the oropharynx cleared by finger sweeping the foreign material out

•If the patient needs artificial ventilation and is producing frothy secretions as rapidly as suctioning can remove them, apply suction for 10 seconds, provide positive pressure ventilation with supplemental oxygen for 2 minutes, then apply suction for another 10 seconds.

Two types of artificial airways

Oropharyngeal and nasopharyngeal

Points to keep in mind when using artificial airways

1) adjunct must be clean and clear of obstructions

2) proper size must be selected

3) airways adjuncts do not protect the airway from aspirations of secretions, blood, vomitus, or foreign substances

4) the mental status of the patient will determine if an adjunct can be used

The oropharyngeal airway (OPA)

Patient must be completely unresponsive and have no gag or cough reflex. Measure the airway by holding it next to the patient's face, should extend the distance from the corner of the mouth to the tip of the ear

Nasopharyngeal airway (NPA)

Use in patients whom the oral airway cannot be inserted because of clenched teeth, biting, or injuries to the maxilla or face. Can be used in patients who are not fully responsive and have a minimally intact gag reflex. Measure from the nose to the tip of the earlobe

Inadequate breathing leads to

Poor gas exchange in the alveoli and ineffective delivery of oxygen to the cells

Determining the adequacy of breathing

Assets the relationship between the volume and the rate at which a patient is breathing

Minute volume

Dept and rate; typically correlates with how adequately the patient is breathing

Tidal volume

Respiratory rate; amount air breathed in and out in one normal respiration

Alveolar ventilation

Amount of air breathed in that reaches the alveoli

Dead air space

Anatomical areas in the respiratory tract where air collects during inhalation but no gas exchange occurs

Minute volume

Tidal volume multiplied by rate

Amount of dead air

150 mL of the 200 mL breathed in

Assessing for adequate breathing

1) look (inspect) chest rise/fall, general appearance, breathing pattern, nostrils

2) listen

3) feel

4) ausculate

Rate

12-20 adults

15-30 children

25-50 infants

Signs of adequate breathing

Normal respiratory rate

Clear and equal breath sounds bilaterally

Adequate air movement heard and felt from nose and mouth

Good chest rise and fall with each ventilation

Rhythm

The pattern is regular

Quality

Equal and full bilateral breath sounds. No excessive accessory muscle use

Respiratory distress

The patient is working harder to breathe

The effects of inadequate oxygen

Brain death in about 4-6 minutes

Respiratory failure

When the respiratory rate and/or tidal volume is insufficient

Respiratory arrest

Apnea; occurs when the patient completely stops breathing

Causes of respiratory arrest

Stroke

MI

OD

Toxic inhalation

Electrocution and lighting strike

Suffocation

Traumatic injuries to the head, spine, chest or abdomen

Infection to the epiglottis

Away obstruction by a foreign body