Chapter 10 Airway Management

A&P applied to Pt. assessment and management à for airway and adequate mechanical ventilation, and respiration.

Standard Competencies

v  Airway Management = Airway anatomy, airway assessment, techniques for assuring patent airway.

v  Respiration = Anatomy, physiology, pathophysiology, assessment & management of adequate and inadequate ventilation, supplement O₂, artificial ventilation.

v  Artificial ventilation = minute ventilation, alveolar ventilation, effect of artificial ventilation on cardiac output,

v  Pathophysiology – for knowledge of pathophysiology of respiration and perfusion to assessment & management.

When breathing disrupted:

v  O2 delivery to tissues & cells compromised à vital organs may NOT funct normally

v  Brain tissue will being to die @ 4 – 6 mins, 6 – 10 damage likely, > 10 mins irreversible brain damage.

Ventilation = Physical act of breathing air into and out of respiratory system.

Following needed for ventilation:

v  Diaphragm

v  Chest wall muscles

v  Accessory muscles of breathing

v  Nerves from brain & spinal cord to those muscles.

Regulation for breathing:

v  pH changes in cerebrospinal fluid

v  hypoxic drive – Late homeostatic system

Ø  Increases RR and depth (tidal volume) when arterial O₂ levels are significantly lowered.

Ø  Vital in patients with chronic airway limitations (eg. COPD) à rely on hypoxic drive to make up for low O2 levels (leaving them chronically with low O₂ %, from 90-92% O₂

v  Air moves into lung due to partial pressure changes.

§  Alveoli pO₂ ~= 104mm Hg

§  Alveoli pCO₂ ~= 40mm Hg

Ø  Not ALL air in Lungs involved in gas exchange:

§  Tidal volume = Amount of air that moves into/out of the lungs during a single breath. (Avg 500mL)

§  Dead space = portion of inspired air that does not reach alveoli.

Ø  Inhalation – As thorax space expands, pressure decreases, inhalation

§  Active muscular part of breathing

Ø  Exhalation – As thorax space compresses, pressure increases, exhalation

§  Does NOT normally require muscular effort

v  Signs of hypoxia:

Ø  Early

§  Restlessness

§  Apprehension

§  Tachycardia

§  Anxiety

Ø  Late

§  Mental status change

§  Weak (thread pulse)

§  Cyanosis

§  Dyspnea

Oxygenation = Process of O₂ loading onto hemoglobin in blood. (required for respiration to take place)

Respiration = Gas exchange at the alveoli for CO₂ release and O₂ intake.

v  External respiration (pulmonary respiration)

Ø  Exchanges O₂ and CO₂ between alveoli and blood in pulmonary capillaries.

v  Internal respiration

Ø  Exchange O₂ and CO₂ between systemic circulatory system and cells of the body

Respiratory anatomy à Refer to A & P reviews

Respiration Pathophysiology:

v  Nervous system à chemoreceptors monitor O₂, CO₂, H⁺ levels of CSF for feedback to brain respiratory center

v  Ventilation/perfusion ratio must match.

Ø  Failure results in lack of O2 diffusing through alveoli.

v  Pulmonary ventilation (airway maintenance)

Ø  Intrinsic issues

§  Infections

§  Allergic reactions

§  Unresponsiveness à tongue obstruction

Ø  Extrinsic issues

§  Trauma

§  Foreign body airway obstruction

v  Respiration (O2 and CO2 diffusion)

Ø  External factors

§  Atmospheric pressure

§  Partial pressure of O2

Ø  Internal factors

§  Pneumonia (fluid in alveoli)

§  Pulmonary edema

§  COPD/emphysema

v  Circulatory system compromise

Ø  Obstruction of blood flow into individual cells and tissue

§  Pulmonary embolism

§  Simple/tension pneumothorax

§  Open pneumothorax

§  Hemothorax

§  Hemopneumothorax

Ø  Other circulatory issues:

§  Anemia

§  Hypovolemic shock – decrease in blood volume

§  Vasodilatory shock – increase in blood vessel diameter à decrease BP

Patient respiratory assessment

v  Adequate breathing

Ø  12 – 20 breaths/min

Ø  Regular pattern

Ø  Bilateral clear and = lung sounds

Ø  Regular, equal chest rise & fall

Ø  Adequate depth (tidal volume)

v  Abnormal breathing

Ø  < 12 breaths/min OR > 20 breaths/min (w/ dyspnea)

Ø  Irregular rhythm

Ø  Abnormal breath sounds

Ø  Unequal/inadequate expansion of the chest

Ø  Shallow depth

Ø  Cyanotic skin, cool, and clammy

Ø  Skin pulls on ribs &/ above clavicles during inspiration (retractions)

Cheyne-Stokes respirations are often seen in patients with stroke or head injury.

Ataxic respirations have an irregular or unidentifiable pattern and may follow serious head injuries.

Kussmaul respirations: deep, rapid respirations commonly seen in patients with metabolic acidosis.

Pulse oximeter should indicate O2 % of > 96%.

v  O2 < 90% à requires treatment unless patient has chronic condition causing the low %.

v  Reading inaccuracies can be caused by:

Ø  Hypovolemia

Ø  Severe peripheral vasoconstriction

Ø  Time delay

Ø  Dirty fingers

Ø  CO poisoning

Emergency airway management

v  Open mouth

Ø  Head-tilt chin lift à medical

Ø  Jaw thrust à trauma

v  IF airway not clear, such as liquid/object obstruction.

Ø  Suction

§  300mm Hg suction when tubing clamped

§  Airflow more than 40L/min

§  NO longer than 15 seconds (adult), 10 seconds (children), 5 seconds (infant)

§  If frothy secretions too much and over produced, suction for 15 mins à ventilate for 2 minutes, rinse and repeat.

v  Airway adjuncts

Ø  Oropharyngeal airways (OPA)

§  Indications:

·       Unresponsive w/o gag reflex

·       Apneic patients being ventilated by BVM

§  Contraindications:

·       Conscious patients

·       Patients w/ gag reflex

§  Measure approx. from corner of mouth to earlobe

§  If gag reflex à NPA

Ø  Nasopharyngeal airways (NPA)

§  Indications:

·       Unresponsive/ altered LOC

·       Patient w/ intact gag reflex

·       Patient unable to maintain his/her own airway

·       Patients who will NOT tolerate OPA

§  Contraindications:

·       Severe head injury w/ blood in nose

·       Hx of fractured nasal bone

§  Measure approx. from nose to earlobe

§  Usually NOT done on patients suffering from severe head injury or history of fractured nasal bones

v  Place patients in recovery position to prevent the aspiration of vomit.

Ø  Do NOT place in this position if trauma to spine, hip, or pelvis is expected.

Supplemental O2

Ø  O₂ cylinders

§  Silver/chrome w/ green area on top

§  Labeled for medical oxygen

§  Type D tank most common

§  Make sure pressure regulatory is firmly attached before transporting

§  Lay down cylinder when possible to avoid knocking it over.

v  ALWAYS provide O₂ to hypoxic patients.

v  NEVER withhold O₂ from any patient that might benefit.

Ø  Hypoxemia worse than O₂ toxicity à apply O₂ when in doubt

Oxygen Delivery Equipment

v  Nonrebreathing masks

Ø  Preferred for patients who are capable of breathing on their own

Ø  Make sure reservoir bag attached to nonrebreather is full before placing onto patient

Ø  Usually 10-15 L/min O₂ flow

Ø  Remove one way valve from mask to create à partial rebreathing mask

§  Allows patients to rebreathe a small amount of their exhaled air à Good for hyperventilating patients.

v  Nasal cannulas

Ø  Deliver O2 through 2 small, tubelike prongs à better for some patients who prefer less claustrophobic exp.

Ø  Usually 1 – 6 L/min flow, this provides from 24% to 44% O2

Ø  Usually Nonrebreather is preferred since, nasal cannula can be bypassed by people who breath through their mouth.

v  Bag-valve mask

Ø  Disposable self-refilling bag + disabled pop off valve + nonrebreathing outlet valve + O2 reservoir + one-way inlet valve with flow up to 15 L/min + transparent face mask

Ø  One person technique

§  Hold mask down on mouth w/ one hand

§  Compress bag with the other hand

Ø  Two person technique

§  One person uses both hands to hold down mask

§  Other squeezes the bag

Ø  Allows for control of manual ventilation

Ø  Useful for patients struggling to breath on their own.

Ø  Usually 15 L/min flow at 100% O₂

v  Tracheostomy masks

Ø  Mask that covers tracheostomy hole w/ strap that goes around the neck.

v  Manually Triggered Ventilation Devices

Ø  AKA flow restricted, O2 powered ventilation devices

Ø  Allows single rescuer to use both hands to maintain mask-to-face seal AND provide positive pressure ventilation.

Ø  Peak of 40L/min @ 100% O₂

Ø  Problems:

§  High incidence of gastric distention à Possible damage to chest cavity

§  Special unit and additional training needed for infants and children

§  NOT to be used w/ COPD, c-spine or chest injuries

v  Automatic transport ventilator (ATV)/resuscitator

Ø  Manually triggered device + control box

Ø  BVM should always be prepared as backup in case of malfunction.

Ø  Constant reassessment of the patient necessary with this method.

Application of O2 Delivery Equipment in Assisted/Artificial Ventilation

v  Assisted Ventilation during respiratory distress/failure

Ø  Signs & symptoms of inadequate ventilation

§  Altered mental status

§  Inadequate minute volume

§  Excessive accessory muscle use and fatigue

Ø  Two treatment options:

§  Assisted ventilation

·       Apply BVM

¨     EXPLAIN to patient before doing it first

·       Squeeze bag each time patient breathes, at same rate of patient

·       After 5 – 10 breaths, slowly adjust rate to deliver correct tidal volume

·       Adjust rate and tidal volume to get good minute volume

§  Other ventilation methods à Artificial ventilation

·       Available methods:

¨     Mouth-to-mask

¨     1 or 2 person BVM

¨     Manually triggered ventilation device

·       Different from normal breathing by forcing air into chest instead of using pressure gradient

¨     Positive pressure à increases intrathoracic pressure (risk of reducing blood pumped to heart)

¨     More volume required than normal pushing airway walls out of normal shape

¨     Air is forced into stomach à gastric distension à risk of vomiting and aspiration

·       Regulate rate and volume of artificial respirations to prevent drop in cardiac output:

¨     Cardiac output = stroke volume * HR

·       Ventilation rate for apneic patients w/ pulse

¨     Adult = 5 to 6 seconds/breath

¨     Child = 3 to 5 seconds/breath

¨     Infant = 3 to 5 seconds/breath

§  Continuous Positive Airway Pressure (CPAP)

·       Generator + Mask + Circuit containing corrugated tubing + Bacteria filter + one way valves

·       Non-ventilatory support for patients w/ respiratory distress

·       CPAP generator creates back pressure to push open airways

·       Uses O2 as driving force to deliver positive ventilatory pressure.

·       Good seal between face and mask is essential to maintain positive pressure.

·       Indications for use:

¨     Patient is alert & able to follow commands

¨     Displays obvious signs of moderate to severe respiratory distress from conditions like COPD.

¨     Breathing rapidly > 26 breathes/min

¨     Pulse oximetry is < 90%

·       Contraindications:

¨     High volume of pressure increases risk of pneumothorax

¨     High pressure in chest can lower BP

¨     Some patients find the process very claustrophobic

Ø  Signs of adequate ventilations:

§  Patient’s color improves

§  Chest rises adequately

§  NO resistance when ventilating

§  Hear & feel air escape as patient exhales

Special Cases

v  Stomas

Ø  Result of those who have had tracheostomies/laryngectomies

Ø  Only use the midline tracheal stoma, ignore other openings

Ø  When ventilation seal patient’s mouth and nose to prevent air leaks

Foreign Body Obstruction

v  Mild Airway Obstruction

Ø  Patients can still exchange air, but w/ varying degrees of respiratory distress

Ø  If patient is capable of breathing, coughing forcefully, or talking do NOT interfere w/ patient’s efforts.

v  Severe Airway Obstruction

Ø  Patient CANNOT breathe, talk, or cough

Ø  Apply Heimlich maneuver

§  IF patient is still unresponsive, and perform CPR @ 30:2 ratio of compressions to ventilations

·       When exposing airway to ventilate look for any obstruction

·       Remove obstruction if possible (Do NOT attempt to reach difficult obstructions à risk of pushing the object further in)

§  After all else fails à begin rapid transport and continue abdominal thrusts on way to hospital