EMT Crash Course: Chapter 9: Airway, Respiration, and Artificial Ventilation

Ventilation

Ventilation

moving of air in & out of the lungs; required for effective oxygenation & respiration

Inhalation

active part of ventilation; energy is required

During inhalation

diaphragm & intercostal muscles contract → intrathoracic pressure decreases → vacuum is created → thorax enlarges → air passes through upper airway to lower airway → gets to alveoli

Exhalation

passive part of ventilation; no energy is required

During exhalation

diaphragm & intercostal muscles relax → thorax decreases → air is compressed out of the lungs

Air obstruction

blockage of an airway structure leading to the alveoli; will prevent effective ventilation

Causes of airway obstruction include

tongue (#1 common cause), fluid (saliva, blood, mucus, vomit), swelling, & foreign bodies

Methods of controlling oxygen delivery

increasing/decreasing rate of breathing & increasing/decreasing the tidal volume of breaths

Hypoxia

inadequate delivery of O2 to the cells

Early indications of hypoxia

restlessness, anxiety, irritability, dyspnea, cyanosis, and tachycardia

Dyspnea

shortness of breath

Late indications of hypoxia

altered/decreased level consciousness, severe dyspnea, cyanosis, and bradycardia

Bradycardia

slow heart rate

Carbon dioxide drive

body's primary system for monitoring breathing status; body monitors CO2 leels in the blood & cerebrospinal fluid

Hypoxic drive

backup system CO2 drive, monitors oxygen levels in plasma, may be used by end-stage chronic obstructive pulmonary disease patients who have high levels of CO2

Prolonged exposure to high concentrations of oxygen in hypoxic drive patients

may depress spotaneous ventilations

Do not _______ from acutely ill/injured patients

withhold oxygen

Oxygenation

delivery of oxygen to the blood; ventilation is required

Oxygenation is required for respiration BUT

does not ensure respiration

Surrounding air

contains about 21% O2

Expired air

contains about 16% O2

Respiration

exchange oxygen & CO2

Heart and brain become irritable due to

lack of oxygen almost immediately

Brain damage begins within

about 4 minutes

Permanent brain damage likely within

6 minutes

Irrecoverable injury is likely within

10 minutes

Airway/Breathing Assessment

• Look for chest rise/fall

• Listen for breathing, ability to speak, & lung sounds

• Feel for air movement & chest rise/fall (Put ear near patient or hand on patient's chest)

Adequate Breathing

normal RR & rhythm, nonlabored breathing, adequate tidal volume, & clear bilateral lung sounds

Inadequate breathing

• Abnormal RR or breathing pattern

• Nasal flaring (enlargement of nostrils)

• Abnormal, diminished, or absent lung sounds

• Paradoxical motion (flail chest segment moves in opposite direction of the thorax

• Unequal chest rise/fall

• Dyspnea, accessory muscle use, retractons

• Cyanosis

• Agonal respiration (dying gasps)

• Apnea (no breathing)

Auscultation

use of stethoscope to listen for lung sounds; left lung field is always compared to right lung field (side to side never top to bottom)

Anterior auscultation

• Place the stethoscope at the midclavicular line about the second intercostal space (2 inches below clavicle but above nipple line)

• Auscultate bilaterally (on both sides of the chest)

• Place the stethoscope at about the 4th intercostal space at midaxillary line

Posterior auscultation

Place the stethoscope at about the midclavicular line & below the scapula bilaterally; lung sounds are often easier to access/hear posteriorly

Normal lungs sounds

clear & equal bilaterally

Absent/diminished lung sounds

indicates little or no air exchange

Wheezing lung sounds

high pitched sounds usually heard during exhalation (lower airway)

Rales

"wet" or "crackling" sounds (upper airway) caused by pneumonia. bronchitis. respiratory infections that cause mucus buildup)

Stridor

high-pitched sounds indicating partial upper airway obstruction (auscultated in upper airway/neck)

Rhonchi

low-pitched sounds resemble snoring (upper airway)

Pulse Oximetry

considered the "sixth vital sign."; Monitoring of oxygen saturation (SaO2) is now part of the standard of care for EMS; often a function provided on cardiac monitor/ defibrillators

SaO2

measures % of hemoglobin (RBC) that are saturated with O2; does not identify definitively how much oxygen is in the blood, but it's an indication of respiratory efficiency

Normal SaO2

>98%, but <945 indicates the need for supp O2

Advantages of pulse oximetry

fast, easy, noninvasive assessment tool

Limitations of pulse oximetry

• Indication of respiratory efficiency, not confirmation

• Cannot measure the amount of hemoglobin, only the oxygen saturation of the hemoglobin that is present

• Other clinical assessments must be performed as well

• Measurement may be difficult to obtain on some patients due to hypovolemia, hypothermia, anemia, nail polish, carbon monoxide poisoning

• Measures saturation of hemoglobin; it can- not distinguish between oxygen saturation and carbon monoxide saturation.

• Time delay between patient's pulse oximeter reading & current RR

Head-tilt-chin left

preferred manual method of opening the airway

Indications for Head-tilt-chin lift

altered/decreased LOC, suspected airway obstruction, requiring suctioning

Contraindications for Head-tilt-chin lift

Suspected c-spine injury

Indications for Jaw-thrust maneuver

patients with altered/decreased LOC AND suspected c-spine injury

Contraindications for Jaw-thrust maneuver

conscious patients

Oropharyngeal airway (OPA)

used to prevent the tongue from obstructing the airway; failure to size or insert OPA correctly can cause the tongue to block the airway; remove OPA if patient gags

Indication for OPA

unresponsive patients without a gag reflex

Contraindications for OPA

conscious patients or any patient with intact gag flex

Sizing OPA

measure from the corner of mouth to earlobe

Inserting OPA in Adults

1. Manually open airway

2. Suction if needed

3. Insert OPA upside down with distal end pointing toward roof of mouth

4. Rotate 180° while advancing OPA until flat

Inserting OPA in Pediatrics

1. Manually open airway

2. Suction if needed

3. Depress tongue with depressing

4. Insert directly or insert sideways and rotate

Nasopharyngeal Airway (NPA)

used to prevent tongue from obstructing airway in patients that can't protect their own airway

Indications for NPA

unresponsive patient w/o gag reflex & patients with decreased LOC but with intact gag preventing use the OPA

Contraindications for NPA

conscious patients with gag reflex that can protect their airway, severe head/facial trauma/injury; resistance to insertion in both nostrils; NPAs are not typically used for patients <1yr

Sizing NPA

measure from tip of nose to earlobe

Inserting NPA

1. Lubricate NPA with water-solube lubricant

2. Always insert NPa with bevel toward septum

3. Try larger nostril first & switch if needed

4. Advance gently, rotating as necessary, DO NOT force

5. Remove immediately if patient gags

6. Suction if needed

Aspiration

entry of matter into lungs, drastically increases risk of death

Indications for Suction

secretions (blood, vomit, mucus, oral secretions, etc.) in the airway that could be aspirated, obstruct the airway, or interfere with ventilations or insertion of a mechanical airway adjunct

Suction should generally be performed

after the airway is opened manually and before insertion of mechanical airway adjunct

Suction units

should be able to generate a vacuum of 300 mmHg when tubing is clamped

Fixed suction

suction unit permanently mounted in a vehicle, hospital

Hand-powered suction

manually powered portable suction unit

Suction catheter

attaches to the suction unit & is inserted into the patient's airway to remove secretions; single-patient use only (tubing & disposable canisters as well)

Rigid suction catheter (tonsil tip or Yankauer)

best suited for suctioning the oral airway

French catheter (whistle-tip)

flexible catheter that comes in several sizes, best suited for suctioning nose, stoma, or inside of advanced airway device

Suctioning increases the risk of

hypoxia

Adults Max Suction time

15 seconds

Pediatric Max Suction time

10 seconds

Infant Max Suction time

5 seconds

Recovery position (patient on his side)

reduces sick of aspiration; unresponsive patients with adequate breathing and no c-spine should be in this position

Supplemental Oxygen

goal → maintain pulse ox of ≥94%, not needed if no signs or resp. Distress or ≥94% pulse ox

Indications for Supp O2

• Cardiac arrest

• Receiving artificial ventilation

• Suspected hypoxia

• Signs of shock (hypoperfusion)

• Pulse O2 < 94%

• Altered/decreased LOC

Oxygen cylinders

seamless steal or aluminum cylinder of various sizes, usually green, can never be left standing unattended, amount of O2 measured in psi (full cylinder has about 2000 psi)

Cylinder should be taken out of service & refilled if below

200 psi

Pin indexing system

safety feature that prevents a CO2 cylinder from being connected to O2 regulator

Flow meters/pressure regulators

Flow meters are connected to pressure regulators. In combination, they re- duce the pressure coming from the tank to safe levels and allow a specific flow rate. The flow rate is measured in liters per minute (lpm or L/ min)

Nonrebreathers (NRB) masks

preferred method O2 admin in prehospital, referred to as "high-flow" O2 admin, available in adult and pediatric sizes

Flow rate of NRB

10-15 LPM

Oxygen delivered in NRB

up to 90%

Cautions of NRB

prolonged use can dry & irritate nasal passage if oxygen is not humidified

Simple face mask

similar to nonrebreather, but w/o oxygen reservoir; flow rate → 6-10 lpm, 40-60% oxygen

Venturi mask

mask delivers precise concentration of low-flow oxygen, rarely used in the prehospital environment

Tracheostomy

surgical procedure that creates an opening through the neck & into the trachea

Humidification of oxygen

increases the moisture of supplemental O2 by flowing it through water prior to inhalation by the patient

Oxygen toxicity

alveoli can collapse due to long-term exposure to high concentrations of oxygen; rarely occurs in prehospital environment

Respiratory depression

risk for COPD patients on the hypoxic drive however, it typically requires long- term exposure to high-concentration oxygen; retinal damage can occur in newborns with lon-term exposure to high concent. O2

Assisted Ventilation (also artificial ventilation or positive pressure ventilation (PPV))

includes mouth to mask, flow-restricted, oxygen-powered ventilation device & automatic transport ventilators and BVM; indicated for any patient with inadequate spontaneous breathing leading to severe respiratory distress or failure

Bronchoconstriction

narrowing of the airways

Pulmonary edema

condition caused by too much fluid in the lungs; This fluid collects in the many air sacs in the lungs, making it difficult to breathe

Apnea

no spontaneous breathing

Agonal breaths

shallow, ineffective gasps

Bradypnea

slow breathing

Tachypnea

fast breathing

Hypoventilation

breathing too slow or shallow

Any unresponsive patient receiving artificial ventilations should have an airway adjust in place to

prevent the tongue from obstructing the airway

Complications of PPV

• Increased intrathoracic pressure, which reduces circulatory efficiency

• Gastric distention, which increases the risk of vomiting & can compromise ventilatory efficiency

Hyperventilation

common mistake; occurs when ventilations are provided too fast, too deep, or both