Chapter 9, Airway Management, Ventilation, and Oxygenation, Wednesday June 10th

Chart not much testing on this;

Physiology

Introduction

• An open airway, adequate ventilation, and sufficient oxygenation are necessary to sustain life.

• You must recognize when to intervene to open and maintain the airway, provide artificial ventilation, and administer supplemental oxygen.

Fix oxygen first.

Cyonosis - look blue

Respiration

1. Pulmonary ventilation

2. External respiration

3. Internal respiration

4. Cellular respiration

Respiratory Physiology

• Respiration is the process of gas exchange.

Oxygenation and removal of carbon dioxide occur as a result of external and internal respiration.

Pulmonary Ventilation

Control of Respiration

Medulla controls respiration

Normal Physiology

Normal respiratory physiology involves the continuous exchange of oxygen and carbon dioxide between the body and the environment. This process sustains cellular metabolism through four key steps: ventilation(breathing in and out), diffusion (gas exchange at the alveoli), perfusion (blood circulation), and regulation(neural control). [1, 2, 3]

1. Ventilation (Mechanics of Breathing)

• Inspiration: An active process where the brainstem signals the diaphragm and external intercostal muscles to contract. This flattens the diaphragm and expands the rib cage, decreasing intrapleural and alveolar pressure below atmospheric pressure, forcing air into the lungs. [1, 2, 3, 4]

• Expiration: A passive process at rest. The inspiratory muscles relax, and the lungs naturally recoil due to elastic tissue, increasing alveolar pressure above atmospheric pressure and pushing air out. [1, 2, 3]

• Key Volumes: A normal adult at rest breathes 12–20 times per minute, moving a Tidal Volume (TV) of approximately 500 mL of air per breath. Roughly 150 mL stays in the "anatomical dead space" (conducting airways) and does not participate in gas exchange. [1, 2, 3]

2. Diffusion (Gas Exchange)

• Blood-Gas Barrier: Air travels down the trachea and branching bronchioles into the alveoli, which are surrounded by pulmonary capillaries. The barrier between them is extremely thin (comprising Type I alveolar pneumocytes, capillary endothelium, and fused basement membranes) to allow rapid diffusion.[1]

• Pressure Gradients: Gases move passively from areas of high partial pressure to low partial pressure. Oxygen (O₂) diffuses from the alveoli into the deoxygenated blood, while carbon dioxide (CO₂) diffuses from the blood into the alveoli to be exhaled. [1, 2, 3]

3. Perfusion & Gas Transport

• Ventilation-Perfusion (V : Q) Matching: For optimal gas exchange, ventilation (air reaching the alveoli) must closely match perfusion (blood flowing through the capillaries). The ideal overall ratio is approximately 0.8 at rest. [1, 2, 3, 4, 5]

• Oxygen Transport: About 98% of oxygen binds to hemoglobin inside red blood cells, while the remaining 2% dissolves directly into the blood plasma. [1, 2, 3]

• Carbon Dioxide Transport: CO₂ is transported out of the tissues in three ways: dissolved in plasma (approx. 7-10%), bound to hemoglobin (approx. 20-30%), and converted into bicarbonate ions (HCO₃⁻) in the blood (approx. 60-70%). [1, 2, 3, 4, 5]

4. Respiratory Regulation

• Neural Control: Breathing is an involuntary process primarily governed by the respiratory centers in the brainstem (medulla oblongata and pons). The medullary center acts as the pacemaker, setting the basic respiratory rhythm. [1, 2, 3, 4, 5]

• Chemical Control: Central and peripheral chemoreceptors constantly monitor the blood levels of CO₂, O₂, and pH. They primarily trigger adjustments to breathing rate and depth to maintain acid-base balance and expel excess CO₂ when metabolic demand increases.

Normal Physiology

Abnormal Physiology of Respiratory System

Abnormal respiratory physiology refers to the inability of the respiratory system to adequately deliver oxygen to the tissues or remove carbon dioxide from the blood. It stems from disruptions in ventilation (air movement), perfusion (blood flow), or gas exchange, resulting in altered breathing patterns and impaired gas exchange. [1, 2, 3, 4]

Key Mechanisms of Impaired Gas Exchange

• Hypoventilation: Breathing is too shallow or slow. The amount of inspired air is insufficient, causing alveolar carbon dioxide to rise and oxygen to fall. [1, 2]

• Ventilation-Perfusion (V/Q) Mismatch: An imbalance between the air reaching the alveoli (\(V\)) and the blood perfusing the capillaries (\(Q\)). For example, pulmonary embolisms block blood flow, while pneumonia or mucus clogs block airflow. [1, 2, 3]

• Diffusion Limitation: Thickening of the alveolar-capillary membrane (e.g., in pulmonary fibrosis) prevents oxygen and carbon dioxide from crossing efficiently. [1, 2, 3, 4]

• Shunting: Deoxygenated blood bypasses the alveoli entirely and enters the systemic circulation without being oxygenated (e.g., severe atelectasis). [1, 2]

Functional Classifications of Lung Disease

Respiratory abnormalities are commonly divided into two main functional categories based on pulmonary function tests: [1, 2]

• Obstructive Defects: Characterized by difficulty exhaling air due to increased airway resistance. Conditions like asthma and COPD result in a reduced \(FEV_1/FVC\) ratio. [1, 2, 3]

• Restrictive Defects: Characterized by a reduced total lung capacity due to a physical inability to fully expand the lungs. Causes range from intrinsic lung tissue stiffening (e.g., pulmonary fibrosis) to chest wall deformities (e.g., kyphoscoliosis) or neuromuscular weakness. [1, 2, 3, 4, 5]

Consequences & Respiratory Failure

When compensation mechanisms fail, the body enters respiratory failure: [1]

• Type I (Hypoxemic): Low oxygen (\(PaO_{2}\)) but normal or low carbon dioxide (\(PaCO_{2}\)).

• Type II (Hypercapnic): Low oxygen (\(PaO_{2}\)) alongside abnormally high carbon dioxide (\(PaCO_{2}\)). [1, 2]

Pathological Breathing Patterns

Breathing patterns often change to compensate for biochemical or neural imbalances: [1, 2]

• Tachypnea: Abnormally rapid breathing (e.g., in response to metabolic acidosis).

• Cheyne-Stokes Respiration: Oscillating cycles of deep/fast breathing alternating with periods of apnea, often seen in central nervous system dysfunction or heart failure.

• Hyperventilation: Breathing deeper and faster than metabolic requirements, leading to abnormally low carbon dioxide levels

Hypoxemia:

• Hypoxemia is a low oxygen content in arterial blood

  • Inadequate ventilation of alveoli despite adequate lung perfusion

  • Inadequate lung perfusion despite adequate ventilation

  • Combination of both

Hypoxia

• Hypoxia means inadequate oxygen is being delivered to the cells

  • Airway obstruction

  • Inadequate breathing

  • Shock (Hypoperfusion)

mild to moderate hypoxia

• Restlessness, anxiety, and agitation

  • Tachypnea 

  • Dyspnea 

  • Pale, cool, clammy skin 

  • Tachycardia 

  • Elevation in blood pressure

Severe hypoxia

• Tachypnea - abnormally rapid, shallow breathing. Normal respiratory rate is 12 to 12 breaths per minute for adults, tachypnea involves taking more than 20 breaths per minute.

• Dyspnea - shorntness of breath or difficulty breathing. Tightnest in chest, air hunger, or inability to catch their breath. More than 20 to 25 breaths per minute

• Cyanosis - is a bluish or purplish discoloration of the skin, lips, or nail beds caused by an abnormally low level of oxygen in the blood. It happens because oxygen-depleted blood is darker and takes on a blue tint, which becomes visible through areas with thin skin or high blood flow

• Tachycardia/dysrhythmias/bradycardia - An arrhythmia is an umbrella term for any problem with the rate or rhythm of your heartbeat. Your heart may beat too quickly (tachycardia), too slowly (bradycardia), or irregularly. A healthy resting heart rate is generally between 60 and 100 beats per minute. [1, 2, 3, 4, 5]

  Tachycardia (Fast Heart Rate)

  Tachycardia occurs when the resting heart rate is faster than 100 beats per minute. [1, 2]

  • Types: Includes Atrial Fibrillation (AFib), Atrial Flutter, and Supraventricular Tachycardia (SVT).

  • Common Causes: Strenuous exercise, stress, fever, or underlying conditions like high blood pressure, thyroid issues, and heart disease. [1, 2, 3, 4, 5]

  Bradycardia (Slow Heart Rate)

  Bradycardia occurs when the resting heart rate is slower than 60 beats per minute. [1, 2, 3]

  • When it's normal: A slow heart rate can occur during sleep and is also common in highly trained athletes.

  • When it's a concern: It becomes problematic if it causes symptoms like dizziness, fainting, or chest pain because the heart isn't pumping enough oxygen-rich blood to the body. [1, 2, 3, 4, 5]

  Tachy-Brady Syndrome

  This is a specific heart rhythm disorder where the heart’s natural pacemaker malfunctions, causing the heart rate to dangerously fluctuate between both extremes. Patients with this condition often require specialized management

• Severe confusion/AMS - Severe confusion or sudden altered mental status (AMS) is always a medical emergency. It is not a diagnosis but a symptom indicating a brain function disruption from an underlying crisis like a stroke, severe infection, or hypoxia.

• Loss of coordination

• Sleepy appearance

• Head bobbing 

• Slow reaction time

Hypoxia results in bradycardia instead of tachycardia

Pediatric differences

Pedi Resp A&P Differences

• Chest wall is pliable

• Increased reliance on diaphragm

• Lungs are easily overinflated in artificial ventilation

• Limited oxygen reserves

• High metabolic rate and oxygen needs

• Hypoxia is the most common cause of cardiac arrest

• Hypoxia may result in bradycardia, instead of tachycardia

  • Very sensitive to changes in oxygenation and perfusion

Geriatric Differences

The aging body

Respiratory Pathophysiology

Cellular Hypoxia

• Inadequate Oxygen delivered to cells

• Disturbance in ventilation or respiration 

  • Anaerobic metabolism results in:

    • Insufficient energy production

    • Buildup of lactic acid

    • Cell dysfunction→ ischemia→ injury → death 

Ischemia is a medical term for a condition where blood flow and oxygen supply to a specific part of the body are restricted. It is typically caused by narrowed arteries or blood clots, and if left untreated, it can lead to severe damage or tissue death (infarction). [1, 2, 3, 4]

Impaired Pulmonary Ventilation

• Etiology: why

  • Interruption of nervous control

  • Damage to thorax

  • Increased airway resistance

  • Loss of airway patency

Impaired Gas Exchange

• Etiology

  • Gas exchange may be impaired by:

    • ↓ ambient oxygen content

    • Lung disease

    • Drowning 

    • Toxic gases

    • Neurological impairment (injury or degenerative process)

• when people drown, epiglottis shuts down.

Hypoperfusion

• Poor perfusion also leads to cellular hypoxia. 

• It may be caused by:

  • Obstructed forward movement of blood

  • Hypovolemia

Hypovolemia is a medical condition characterized by an abnormally low volume of circulating blood or extracellular fluid in the body. It is primarily caused by significant fluid loss through trauma, internal bleeding, severe vomiting, diarrhea, or excessive sweating, and requires immediate management to prevent circulatory failure

Airway Assessment

Airway Assessment and Management

• Patency

  • Conscious Pt- if speaking- airway patent (in general)

  • Altered or Unconscious

    • You must open the mouth to assess the airway

    • Clear the airway of liquids or foreign bodies

POSITIONING- Conscious or unconscious

Hear gurgling, hear fluid, suction it out.

Signs of an Open Airway

Air can be felt and hard moving in and out of the mouth and nose

The patient is speaking in full senates or with little difficulty

The sound of the voice is normal for the patient

Signs of a Blocked or Inadequate Airway

Abnormal upper airway sound (stridor, snoring, crowing, or gurgling)

An awake patient who is unable to speak

evidence of a foreign body airway obstruction (tongue, food, vomit, blood, or teeth in the upper airway, mouth or nose)

swelling to the mouth, tongue, or oropharynx.

Upper Airway sounds.

• Snoring

  • caused by the tongue obstructing the airway

• Crowing

  • caused by muscle spasms around the larynx

• Gurgling

  • caused by liquid in the airway

• Stridor - something in there.

  • swelling of the larynx

Airway Assessment and Management

• Opening the airway

  • Manual maneuvers

    • Once open- maintain open

  • Suction

    • Rigid and soft

  • Mechanical airways

    • Oral and Nasopharyngeal 

Picture

Picture

Picture

Unpatient Airway

Open the airway

Jaw Thrust Maneuver

picture

Recovery Position

Suction

• Gurgling indicates liquid in the airway.

• Use suction to remove blood, vomitus, secretions, and any other liquids, food particles, or objects from the mouth and airway

• Suction devices must generate enough negative pressure to remove fluids from the airway

Suction Equipment

• May be mounted in the ambulance or portable

• Must generate enough vacuum and airflow to clear the airway

• Must have wide-bore, thick tubing, a collection bottle, and water supply

• Catheters

  • Rigid (Yankauer/DuCanto)

  • Soft (French Tip)

  • Tubing (for large secretions in mouth)

Suction Pearls

• Rigid catheter -the mouth and oropharynx

• Soft catheter  - nose, nasopharynx, mouth and oropharynx

• Tubing- large secretions

• Insert only as far as you can see into the mouth.

  • Avoid touching the back of the oropharynx.

• Suction < 15 sec on removal of catheter

No more than 15 seconds of suctioning.

Airway Adjuncts

• Used in conjunction with manual airway maneuvers

  • Does not take the place of keeping airway open with head-tilt, chin-lift or jaw-thrust 

  • If the patient becomes more responsive or gags, remove the adjunct.

• Includes oropharyngeal and nasopharyngeal airways

  • The proper size airway adjunct must be selected.

  • Airway adjuncts do not protect from aspiration into the lungs.

Oropharyngeal Airways

• Oropharyngeal airways are used in patients who are unresponsive, without a gag reflex.

• The device must be sized properly

  • Measure from corner of mouth to tip of ear

  • Place either directly with tongue blade -or-

  • Insert bevel up and rotate when you meet resistance of soft palate

Nasopharyngeal Airways

• Oropharyngeal airways are used in patients who are unresponsive, without a gag reflex.

• The device must be sized properly

  • Measure from corner of mouth to tip of ear

  • Place either directly with tongue blade -or-

  • Insert bevel up and rotate when you meet resistance of soft palate

• May cause gagging or vomiting

• Does not prevent aspiration

• Insertion

  • May cause trauma to nasal mucosa; must be lubricated

  • Measure from tip of nose to ear

  • Insert in nare (usually right) with bevel toward septum

Creates channel: Nasal

If one adjunct, positioning, and airway maneuvers are not sufficient, you may combine them

Breathing Assessment and Management

Topics

1. Breathing Assessment

2. Deciding to Ventilate

3. Techniques of Artificial Ventilation

4. Special Considerations

5. Oxygen Therapy

Assessment of Breathing

• Establish a patent airway

• Assess the adequacy of the patient's breathing

  • Inadequate breathing leads to poor gas exchange in the alveoli inadequate oxygenation.

  • Focus on the rate of breathing, the volume of each breath, and rhythm

Minute Volume

• A function of both respiratory rate and tidal volume

  • A change in either respiratory rate or tidal volume affects minute volume.

  • Minute volume = RR x TV

    • 5-8L/min (10+L/min - hyperventilation)

• What would cause changes in tidal volume and respiratory rate?

Alveolar Ventilation

• Alveolar ventilation is the amount of air breathed in that reaches the alveoli.

  • Alveolar ventilation = (tidal volume – dead space air) × respiratory rate

• Dead air space does not change when tidal volume decreases.

• Rapid respirations can decrease the tidal volume.

Anything above 12 or under 8 breaths per minute is inadequate breathing. Also dependent on patient

Dead space: Upper airways to lower airways. Air is there but is not moving.

Assessing for Adequate Breathing

• ASSESS

  • Rate 

  • Rhythm 

  • Quality

  • Depth  

• by looking, listening/auscultating, feeling

Are they getting adequate breathing to the bases of the lungs. Make sure air is moving to bases and top as well.

Breathing Patterns

diabetic patients: hyperglycemic

Respiratory patterns

Signs of Adequate Breathing

• normal respiratory rate

• clear and equal breath sounds bilaterally

• adequate air movement heard and felt from nose and mouth (tidal volume)

• good cheer rise and fall with each ventilation (tidal volume)

Respiratory Distress vs. Failure vs. Arrest

• Respiratory distress

  • Breathing can be adequate, but if the patient is working harder to breathe

• Hypoxia→ cells in brain begins to die within 4 to 6 minutes.

• Inadequate breathing can be categorized as respiratory failure or respiratory arrest.

  • Patients with respiratory failure or arrest require immediate positive pressure ventilation.

Causes of Respiratory Distress/Failure

• Stroke - brain injury

• Myocardial infarction - heart attack

• Drug overdose - opioid overdoses especially

• Toxic inhalation - hydrogen cyanade gas

• Electrocution

• Suffocation - walking into a room filled with gas

• Traumatic injuries - phrenic nerve

• Infection of the epiglottis - blockages

• Airway obstruction - blockages

epligottis is horrible for kids because there airways are small

Signs of Inadequate breathing

Picture

Oxygen Therapy and Artificial Ventilations

Making a Decision: Should I assist ventilation or Apply oxygen?

Effects of Positive Pressure Ventilation

• PPV does not rely on negative pressure

• Air is forced into the alveoli.

• PPV ↑ airway wall pressure

• PPV can lead to gastric distention by overcoming esophageal opening pressure, 

• Negative pressure from spontaneous breathing assists blood return to the heart

  • PPV decreases cardiac output.

If nothing moving give PPV. You can give epinephrine 0.3.

Force air into their alveoli - do this through CPAP ;BVM

Rules of Threes for Ventilation - skipped in slideshow

• Three providers

• Three inches

• Three fingers

• Three airways

• Three PSI

• Three seconds

Artificial Ventilation

• You must be able to maintain a good mask seal.

  • 2 EMTs

  • Pull face into the mask

• The device must deliver an adequate volume of air to inflate the lungs.

  • Chest Rise

Adequate Ventilation

• Perfusing

  • Newborns- 40-60/min

  • Infants/young children- 12-20/min or once every 3-5 seconds

  • Adults- 10-12/min or once every 5-6 seconds

  • Deliver each breath over 1-2 seconds

  • If spontaneously breaths- sync to pt’s rate

• Cardiac arrest

  • Newborns→ 3:1

Infants, children and adults---> 30 to 2

• Consistent tidal volume, sufficient to cause chest rise

• Heart rate returns to normal

• Color improves

Inadequate Ventilation

• Ventilation rate is too fast or too slow.

• The chest does not rise and fall.

• The heart rate does not return to normal.

• Color does not improve.

• Does airway need to be repositioned?

• Additional provider needed?

• Cricoid Pressure needed?

Sellicks Manuever - skipped in slideshow

• Cricoid pressure is not recommended for routine use, but can be used in some situations.

  • Adult intubation

  • Pediatric patient when an extra EMT is available

  • BURP- backwards, upward, rightward pressure

Avoiding Gastric Inflation

• Leads to regurgitation and aspiration, and impaired ventilation

• Reduce the tidal volume delivered and use supplemental oxygen to maintain oxygenation with a smaller tidal volume

  • MORE isn’t necessarily BETTER

Mouth to Mask Ventilation

• Advantages

  • A single EMT can maintain a good seal with the mask.

  • Eliminates direct contact with the patient

  • One-way valve prevents exposure to the patient's exhaled air.

  • Provides adequate tidal volume

  • Supplemental oxygen can be administered.

• Disadvantages

  • The mask is perceived by some EMTs as having an increased risk of infection.

  • The EMT providing ventilation may fatigue.

  • Doesn't allow for the highest possible concentration of oxygen to be delivered

Bag Valve Mask

• Select the appropriate size and use only enough volume to cause the chest to rise.

• Two-person technique is preferred.

  • Position the mask, use an "E-C" technique.

  • A second EMT squeezes the bag 

• Can deliver close to 100% oxygen

• May allow medication administration

Ventilating a Spontaneously Breathing Patient

• Recognize the need to ventilate a patient who is breathing, but breathing inadequately.

• Complications include uncooperative patients, inadequate mask seal, and overinflation of the lungs.

• Explain the procedure to the patient.

• Ventilate to achieve the normal rate and/or tidal volume.

FROPVD - skipped in slideshow

• Flow-restricted, oxygen-powered ventilation device

• A manually triggered ventilation device

• Delivers 100% ventilation

• Can be used by one EMT using a two-handed technique to seal the mask

• Only for adult patients, not currently allowed in MA

CPAP

• Continuous positive airway pressure

• A form of noninvasive positive pressure ventilation

  • CPAP can help avoid the need for endotracheal intubation in some patients.

• Used in awake, spontaneously breathing patients who need ventilatory support

Oxygen should be titrated to the patient's SpO₂ reading, and signs and symptoms.

• Positive pressure is measured in cmH₂O.

• Positive pressure helps inflate collapsed alveoli and improve oxygenation.

• Decreases the work of breathing

• Helps displace fluid in alveoli in left ventricular failure

• Delivered at 2 to 20 cmH₂O

  • Begin at ~5 and titrate to pt response

• Patient criteria

  • Awake and can obey commands

  • Can maintain his airway

  • Breathing on his own, respiratory distress 

  • Has signs and symptoms of moderate to severe respiratory distress, or early respiratory failure

Putting a lot of pressure into chest. Squeezes vena cava, slows return of blood to heart which lowers blood pressure. That’s why patients need to have good blood pressure to put this on.

PEP; holds alveoli open. Five pep is enough to hold alveoli open. Posive and expiatory pressure.

Also improves oxygenation and saturation. Opening up more collapsed alveoli.

pneumonia, asthma, Congestive heart patients. used it on an ALS patient.

CPAP Contraindications

• Apnea or agonal respirations

• Inability to follow commands

• Inability to maintain an airway

• Unresponsive

• Shock with cardiac insufficiency

• Upper GI bleeding

• Pneumothorax or chest trauma

• Tracheotomy

• Facial trauma

• Increased intrathoracic pressure

• Cardiac arrest

• Vomiting

Don’t put CPAP if any of this above. Any trauma, no CPAP.

Special Considerations in Airway Management and Ventilation

stomas

trachaeostimy.

capnagrophy - measure the perfusion

Facial Injuries

• Swelling can occlude the airway.

• Use an airway adjunct if needed.

• Avoid a nasopharyngeal airway in patients with mid-face trauma.

• Bleeding may require frequent suctioning.

might require constant suctioning

Obstructions

• Foreign body airway obstruction

  • If a patient is choking but is effectively moving air, instruct him to cough; administer high-concentration oxygen.

  • If air exchange is poor, manage as for a complete airway obstruction.

• For a child or adult, perform abdominal thrusts for complete airway obstruction.

• For an infant, perform chest thrusts and back blows for a complete airway obstruction.

Denial Appliances

Take dentures out

Oxygen Therapy

• 100% oxygen is stored in cylinders.

• Cylinder volume varies.

• Pressure in a full cylinder is 2,000 psi.

• For long transports, calculate the duration of flow for the cylinder.

• Safety when using, storing….

Oxygen Duration

Regulators

Oxygen Therapy Indications

• Signs of hypoxia and adequate respirations including AMS, SpO₂ < 94%

• When in doubt, give oxygen.

• Never withhold oxygen from a patient who needs it!

• Titrate oxygen to patient’s needs

Normal O2 saturation - 98 percent

Oxygen Therapy Decision Making

• Too much oxygen can worsen conditions especially CVA and ACS  

  • Vasoconstriction, free radicals

  • worse M&M

• Begin administration at 2 lpm by nasal cannula.

Oxygen Delivery Devices

• Nasal Cannula

• Non-rebreather mask

• Simple face mask

• Partial rebreather mask

• Venturi mask

• Tracheostomy mask

Nasal Cannula

• A nasal cannula is used to deliver a lower concentration of oxygen.

• The flow rate is 2lpm - 6lpm

NRB Mark

Oxygen Humidifiers

Ventury mask. different color. Give certain percentage

Flaled chest - ventilate them