Airway Management and Oxygen Therapy

INTRODUCTION

One of the most critical skills that the medic must know is airway management. Without proper airway management techniques and oxygen administration, your patient may die needlessly. The medic must be able to choose, and effectively use, the proper equipment for administering oxygen for both the medical and trauma patients.

Review anatomy and physiology of respiratory system

Anatomy of upper and lower airway

(1) Nasal cavities

(a) Structures

(i) Nostrils

(ii) Nasal cavities

(iii) Nasal septum

(iv) Sinuses

(b) Functions

(i) Filter foreign bodies

(ii) Air is warmed by blood in vascular membrane

(iii) Air is moistened by liquid secretion

(2) Pharynx

(a) Structure

(i) Nasopharynx

(ii) Oropharynx

(iii) Laryngeal pharynx

(b) Function

(i) Carries air into respiratory system

(ii) Carries food and liquid into digestive system

(3) Larynx

(a) Structure

(i) Epiglottis

(ii) Glottis

(iii) Thyrohoid Cartilage

(iv) Cricoid Cartilage

(v) Corriculate Cartilage

(vi) Arytenoid Cartilage

(vii) Thyrohyoid Ligament

(iv) Vocal Cords

(b) Function

(i) Serves in production of speech

(i) Beneath the thyroid cartilage is the cricoid cartilage

(ii) Cricoid cartilage forms inferior walls of larynx and is attached to trachea's first ring of cartilage. This makes it a solid piece of cartilage posteriarly and protects structures deep to it during cricothyroidotomy.

(iii) Connecting the inferior border of the thyroid cartilage with the superior aspect of the cricoid membrane is the cricothyroid membrane

(4) Trachea

(a) Structure

(i) Tube that extends from lower edge of larynx to upper part of chest above the heart

(ii) Framework C-shaped of cartilage keeps it open

(iii) All open sections of cartilage are back so esophagus can bulge into region when swallowing

(b) Function - conducts air between larynx and lungs

(5) Bronchi and bronchioles

(a) Structure

(i) Trachea branches off into two bronchi which enter the lungs

(ii) Right bronchus is considerably larger in diameter and straighter than the left making it more prone to foreign bodies becoming lodged there

(iii) Left bronchus goes off at a greater angle

(b) Function - passageways to bring air to alveoli

(6) Lungs

(a) Structure

(i) Extremely thin and delicate tissue

(ii) Two lungs sit side by side in thoracic cavity

(iii) Two cone-shaped structures with their bases lying on diaphragm

(iv) "Bronchial Tree" - subdivisions of bronchus

(v) Bronchioles - smallest division of bronchi

(vi) Terminal bronchioles - attached to alveoli

(vii) Alveoli - cluster of air sacs, resembling bunch of grapes

(viii) Surfactant - substance that prevents alveoli from collapsing by reducing the surface tension of fluids that line them

(b) Function - gas exchange takes place as blood passes through capillaries around alveoli

(7) Thoracic cavity

(a) Lungs occupy considerable portion of thoracic cavity

(b) Separated from abdominal cavity by diaphragm

(i) Visceral pleura

(ii) Parietal pleura - continuous with visceral pluera and lines the internal surface of the thoracic cavity

(d) Mediastinum - region between lungs (contains heart, great blood vessels, esophagus, trachea, and lymph nodes)

(e) Pleural space - potential space between two membranes of parietal and visceral pleura

Review gas exchange

(1) Inhalation

(a) Initiated by contracting of respiratory system muscles

(b) Diaphragm flattens and drops down

(d) Enlargement of thorax causes pressure in lungs to fall and forces air into lungs

(2) Exhalation

(a) Respiratory muscles relax. Diaphragm moves up

(b) Chest wall recoils

(d) Air is pushed out

(3) Gas exchange in lungs

(a) Alveoli where O2 and CO2 exchange occurs

(b) Exchange is made by diffusion across cell wall of alveoli and capillaries

(4) Carbon dioxide in blood

(a) Acid-base balance directly related to CO2 produced and CO2 eliminated

(b) CO2 is transported from tissues to lungs

Review respiratory rates and tidal volumes

(1) Respiratory volumes

(a) Total lung capacity - volume of gas contained in lung at end of maximal inhalation (4000 - 6000cc)

(b) Tidal volume - volume of gas inhaled or exhaled during normal respiratory cycle (500cc)

(d) Alveolar air - amount of air which reaches the alveoli and participates in gas exchange with capillary blood (350cc)

(2) Respiratory rates

(a) Adult - 12-20 per minute

(b) Children - 20-40 per minute

Establish an airway

Perform manual maneuvers

(1) Head-tilt, chin-lift

(a) Once casualty is in supine position, place one hand on forehead and place fingertips of other hand under bony area at center of casualty's lower jaw

(b) Tilt head by applying gentle pressure to casualty's forehead

(c) Use fingertips to lift chin and to support lower jaw. Move jaw forward to point where lower teeth are almost touching upper teeth.

(d) Do NOT allow casualty's mouth the be closed

(2) Jaw-thrust

(a) Keep casualty's head, neck, and spine aligned

(b) Take position at top of casualty's head resting your elbows on same surface the casualty is lying on

(d) Stabilize casualty's head with forearms

(e) Using index fingers, push angles of casualty's lower jaw forward

(f) You may need to retract the casualty's lower lip with your thumb to keep the mouth open

(g) Do NOT tilt or rotate the casualty's head

Insert nasal airway adjunct

NOTE: Do not use the nasopharyngeal airway if you see the roof of the mouth is fractured or brain matter is exposed. The airway may enter the cranial cavity.

(1) Purpose-to maintain an artificial airway for oxygen therapy or airway management when suctioning is necessary

(2) Indications-when oropharyngeal airway cannot be used

(a) Casualty is conscious, semi-conscious, or has a gag reflex

(b) Casualty has injuries to mouth (e.g. broken teeth, massive oral tissue damage)

(d) When vomiting is likely to occur

(3) Complications

(a) Possible complication resulting from device is nasal trauma

(b) Some casualties, a nasal airway will trigger gag reflex: Do NOT use nasopharyngeal airway if there is evidence of head injury or if drainage of cerebrospinal fluid (CSF) from nose, mouth, or ears is present. CSF may indicate a skull fracture and the airway might enter the cranial cavity. Follow SOPs.

(4) Nasopharyngeal insertion procedures

(a) Place the casualty on a firm surface in the supine position with C-spine stabilized

(b) Select proper size nasopharyngeal airway

(i) Diameter-select an airway with a diameter smaller than the casualty's nostril or one that is approximately the diameter of the casualty's little finger

(ii) Length-measure from tip of patient's nose to ear lobe

(d) Push tip of nose slightly up to expose opening in nostril

(e) Keeping the head in a neutral position, insert tip of airway through nostril

(f) Slowly advance tube along floor of nasal cavity until flange rest firmly against casualty's nostril

(i) If resistance is met during insertion, DO NOT continue

(ii) Stop, remove adjunct, relubricate and try other nostril

(iii) If resistance is still met, check proper size or use alternate artificial airway method

(g) Administer oxygen therapy and ventilate casualty at this time if necessary. Follow local protocol

(h) To remove the airway, pull out with a steady motion along the curvature of the nasal cavity

Insert oral airway adjunct

(1) Purpose

(a) To hold the tongue away from the back of the throat, thereby preventing an airway obstruction (in a person without gag reflex)

(b) Also allows for drainage and/or suction of secretions to prevent aspiration

(2) Indication-utilized for the unconscious patient without a gag reflex

(3) Complications

(a) Induces vomiting and aspiration when gag reflex is present

(b) Airway obstruction from tongue may occur with improper placement: If the oropharyngeal airway is inserted into a patient with a gag reflex, vomiting or spasms of the vocal cords may occur, causing airway obstruction.

(4) Oropharyngeal insertion procedures

(a) Place patient on a flat surface in a supine position

(i) Non-trauma patient-use head-tilt, chin-lift method

(ii) Trauma patient-minimize neck movement using jaw-thrust maneuver

(b) Maintain airway by utilizing manual techniques and/or mechanical devices (e.g., head-tilt, chin-lift, jaw thrust airway adjuncts)

(c) Select the proper size airway by measuring from the earlobe to the corner of the mouth or from the center of the casualty's mouth to the angle of the lower jaw bone

(d) With non-dominant hand, use the cross-finger technique to open the patient's mouth

(e) Visualize inside the mouth, and suction if necessary: Do NOT use the oropharyngeal airway if you see that the roof of the mouth is fractured or brain matter is exposed. The airway may enter the cranial cavity.

(f) Holding the adjunct in the dominant hand, position the correct size airway so that the tip is pointing toward the roof of the casualty's mouth

(g) Insert airway into casualty's mouth by sliding tip along the roof past the uvula or until resistance is met by the soft palate

(h) Gently rotate the airway 180 degrees, so tip is positioned behind back of tongue

(i) The flange of the airway should rest against the casualty's lips

(j) If J-tube is too large for casualty, more than a 1/4 of length protruding from lips, remove and choose proper size to prevent occlusion of airway.

(k) Administer oxygen, ventilate as necessary, IAW SOPs

(l) Monitor casualty closely. If the casualty gags or regains consciousness, remove the airway immediately

(m) Remove airway by pulling out with the natural curvature of the mouth, DO NOT rotate

(n) Vomiting may occur with airway removed; have suction device ready when removing airway adjunct.

Consider cricothyroidostomy

NOTE: This section is for familiarization only. The medic will not perform this procedure.

(1) Casualty preparation

(a) Place casualty in a supine position

(b) Slightly hyperextend the casualty’s neck (If suspected cervical injury do not hyperextend neck).

(2) Assemble and prepare equipment and supplies

(a) Scalpel/scalpel handle/knife

(b) Suctioning device, if available

(d) Needle holders

(e) Cannula (non-collapsible tube to maintain airway)

(f) Blanket

(g) Gloves

(h) Tape

(i) Establish a sterile field

(3) Overview of procedure

NOTE: This procedure is performed by MD/PA. The medic should not attempt to perform.

(a) Position the casualty for procedure (supine position). Strict surgical aseptic technique is followed during procedure.

(b) Surgically prepare the area and assist the MD/PA in anesthetizing the area locally, if the patient is conscious/time permits

(d) Assist the MD/PA in stabilizing the trachea to prevent lateral movement of the trachea during the procedure

(e) Provide the MD/PA the cannula and assist as necessary with insertion. Cannula may be a cuffed endotracheal tube of appropriate size or tracheostomy tube. Inflate the cuff of the tube and ventilate patient.

(f) Provide supplemental oxygen

(g) Secure the cannula in place to reduce movement in the opening and to prevent inhalation of the cannula.

(h) Suction and or assist the MD/PA in suctioning the casualty’s airway, as necessary.

(i) Insert the suction catheter 4 to 5 inches into the cannula

(ii) Apply suction only when withdrawing the catheter.

(iii) Administer 1 cc of saline solution into the airway to loosen secretions and help facilitate suctioning, if indicted

(iv) When directed by MD/PA, apply a sterile dressing under the casualty’s cannula and make a Y-shape fold in a 4X4 gauze pad and place under the edge of the cannula to prevent irritation to the incision.

(5) Assist with on-going patient assessment/management

(a) Continue to monitor vital signs to include pulse oximetry, if available.

(b) Assist with ventilation as necessary.

(i) Aspiration

(ii) Asphyxia

(iii) Laceration of the esophagus/trachea

(iv) Mediastinal emphysema

(v) Hemorrhage/hematoma formation

Consider chest needle decompression

(1) Indications - This procedure is applicable to the rapidly deteriorating casualty with a life threatening tension pneumothorax with decompression as evidenced by

(a) Respiratory distress and cyanosis

(b) Decreasing level of consciousness

(2) Materials required to perform the procedure

(a) A minimum of a 2 inch, 12 to 14 gauge I.V. needle with catheter

(b) Betadine or alcohol prep pads

(3) Review anatomy of the chest and identify the following anatomical landmarks on the side of the tension pneumothorax

(a) Mid-Clavicular line

(b) Second Intercostal space - superior edge of the 3rd rib

(4) Steps for performing the procedure

(a) Position of Casualty: this procedure is not dependant on any single position that the casualty may be in or able to be moved to. Casualty may be lying flat, sitting etc

(b) Site preparation: Preparation of the site is accomplished using either alcohol and or betadine prep pads to disinfect the skin

(c) Using your index finger trace the mid clavicular line, then Identify the second intercostal space (between the second and third ribs) on the side of the tension pneumothorax

(d) Insert the needle perpendicular to the chest wall, directly over the top of the third rib until a palpable pop is felt followed immediately by a hissing of air escaping from the chest cavity

(e) A rush of air confirms the diagnosis and rapidly improves the patient's condition

(5) Complications

(a) Laceration of the intercostal vessels my cause hemorrhage. The intercostal artery and vein run around the inferior margin of each rib. Poor needle placement can lacerate one of these vessels

(b) Creation of a pneumothorax may occur if not already present. If your assessment was incorrect you may create a pneumothorax when you insert the needle into the chest

(d) Intercostal nerve/artery injury is possible if the needle is placed beneath the rib accidentally

(e) A tube thoracostomy should be accomplished by a PA/MD ASAP as the needle may be inadequate to continuously decompress the chest if a major bronchus is ruptured

Review concepts of airway management

Objective of airway maintenance

(1) Immediately establish and maintain a patent airway

(2) Determine whether casualty is breathing

(3) Consider artificial ventilation

Identify neglected prehospital skills related to airway

(1) Need for oxygen and artificial ventilation

(2) Properly establishing and maintaining an open airway

Review modified forms of respiration

(1) Coughing

(a) Forceful exhalation of a large volume of air from lungs

(b) Serves a protective function

(2) Sighing

(a) Slow, deep inspiration followed by a prolonged expiration

(b) Sighing hyperinflates lungs and re-expands atelectatic areas

(3) Grunting: indication of respiratory distress

Review terminology

(1) Hyperventilation - An increase in the number of resperations per minute above the normal range for a given age group.

(2) Hypoventilation - A decrease in the number of respirations per minute that falls below the normal range for a given age group.

(3) Compliance - the ability of the lungs and chest wall to expand and ventilate a patient, supports whether or not you can adequately ventilate.

Assess for respiratory obstruction

Type of respiratory obstruction

(1) Partial

(a) Allows for either adequate or poor air exchange

(b) Adequate exchange makes it possible for patient to cough effectively

(d) Often give off high-pitched noise while inhaling

(e) May also experience increased breathing difficulty and cyanosis

(2) Complete

(a) Airflow is neither felt nor heard from nose and mouth

(b) Casualty cannot speak, breathe, or cough

(d) Can be recognized by difficulty encountered when trying to ventilate the casualty

Source of respiratory obstruction

(1) Tongue

(a) Most common cause of airway obstruction

(b) In absence of sufficient muscle tone, the relaxed tongue falls back against rear of pharynx

(d) Can occur regardless of whether casualty is in lateral, supine, or prone position

(2) Foreign body: Largely, poorly chewed pieced of food can obstruct upper airway by becoming lodged in laryngopharynx

(3) Trauma/Combat

(a) Airway may be obstructed by:

(i) Loose teeth

(ii) Facial bone fractures

(iii) Tissue

(iv) Clotted blood

(v) Neck wound

(b) Penetrating or blunt trauma may obstruct airway by fracturing or displacing larynx, allowing vocal cords to collapse into tracheal lumen

(4) Laryngeal spasm

(a) Moderate amounts of edema can severely obstruct airflow through the glottis and result in asphyxia

(b) Causes can include:

(i) Anaphylaxis

(ii) Epiglottis

(iii) Inhalation of super-heated air, smoke, or toxic substances

(5) Aspiration

(a) Dentures, teeth, and vomitus are likely to obstruct the airway

(b) If allowed to enter the lungs, can result in increased interstitial fluid and pulmonary edema

(d) Can usually be avoided by proper airway management and suction

(6) Inadequate ventilation

(a) A reduction of either rate or volume of inhalation leads to a reduction of either rate or volume of inhalation

(b) Respiratory rate may be rapid, but depth of breathing is so shallow that little air exchange takes place

(i) Depressed respiratory function

(ii) Fractured ribs

(iii) Drug overdose

(iv) Spinal injury

(v) Head injury

Provide emergency medical care

(1) Heimlich maneuver (Only if choking, not in trauma)

(a) Stand behind casualty and wrap arms around waist

(b) Place a fist thumb-side toward abdomen, midway between xiphisternal notch and navel

(c) Grasp properly positioned fist with other hand and apply pressure inward and up toward casualty's head. Deliver five rapid thrusts

(d) For unconscious casualty, place in supine position. Kneel and straddle casualty at level of thighs, facing chest.

(2) Finger sweep

(a) Open mouth by grasping tongue and lower jaw together with one hand and lifting

(b) Sweep a curved index finger from far side of mouth along the cheek, deeply into back of throat, and then out the near side

(3) Chest thrusts (Only if choking, not in trauma)

(a) Place hands in position for closed chest compression

(b) Deliver 6-10 distinct thrusts in rapid succession

(4) Suctioning: To remove vomitus, blood, and other fluids and secretions from the airway

Provide oxygen if casualty is found not breathing

Apply mouth-to-mask (mouth-to-mouth) ventilation

(1) Position yourself at casualty's head and open the airway. If trauma is suspected, open using jaw-thrust technique.

(2) Connect oxygen to inlet on face mask. Oxygen should run at 15 liters per minute.

(3) Position mask on casualty's face so that apex is over bridge of nose and base is between lower lip and prominence of chin

(4) Hold mask firmly in place while maintaining the proper head tilt

(5) Take a deep breath and exhale into make port

(6) Remove mouth from port and allow for passive exhalation

Apply one person bag-valve-mask

(1) Position yourself at casualty's head and establish an open airway. If trauma is suspected, open using jaw-thrust technique.

(2) Select correct size mask

(3) Form a "C" around ventilation port with thumb and index finger

(4) With other hand, squeeze bag once every 5 seconds

(5) Release pressure on bag and let casualty exhale passively

(6) Observe for gastric distension, changes in compliance of bag with ventilation, improvement or deterioration of ventilation status

Apply two person bag-valve-mask: noninvasive

(1) Open casualty's airway using jaw thrust technique (if trauma is suspected)

(2) Select correct bag-valve mask size

(3) Kneel at patient's head. Place thumbs over nose portion of mask and place you index and middle fingers over portion of mask that covers the mouth.

(4) Use your ring and little fingers to bring the jaw upward, toward the mask.

(5) Second rescuer should squeeze the bag once every 5 seconds (with two hand techinique) to ventilate the casualty

Suction the airway

NOTE: The first opportunity for suctioning will be in the field ambulance (FLA). (In relation to only on the battlefield)

Purpose-to keep airway clear of all foreign matter (e.g., blood, saliva, vomitus, debris) which could be aspirated into the trachea or the lungs

Indications

(1) Casualties that have a decreased level of consciousness and are unable to clear their own airway

(2) Casualties who cannot clear airway because of excessive amounts of foreign matter

Suction Steps and Procedures

(1) Preoxygenate the casualty for 1 to 2 minutes to increase the oxygen saturation in the blood. This reduces the risk of causing hypoxemia.

(2) Position casualty

(a) Non-trauma/conscious casualty--position yourself at the casualty's head and turn casualty's head to the side

(b) Trauma/unconscious casualty--position yourself at the casualty's head and maintain spinal alignment while log rolling casualty towards you

(3) Select and measure the suction catheter

(a) Flexible suction catheter

(i) Sterile tube used for oropharyngeal or nasopharyngeal suctioning of fluids of small foreign particles

(ii) Sized in French (Fr.) guage

(b) Yankaeur suction tip (tonsil tip)

(i) Used for oral suction only

(ii) Not necessary to measure, just keep sight of the tip when inserting it

(iii) Large-bore opening - preferred method of removing large particles of foreign material

(iv) Only one size

(i) Oral

(ii) Nasopharyngeal

(iii) Nasotracheal

(4) Check suction unit and equipment

(a) Ensure power source is available and unit is functioning before beginning the procedure

(b) Cover the proximal port with your thumb and set the suction vacuum at 100-120 mmHg for an adult or child, and 60-100 mmHg for an infant

Perform oropharyngeal suctioning

(1) Open casualty's mouth using the crossed finger technique and clear the mouth of any visible fluids or obstructions with gloved finger

(2) Suction apparatus placement

(a) Suction tip--insert with the convex (bulging out) side against the roof of the mouth and stop at the beginning of the pharynx

(b) Suction catheter--insert the catheter up to the base of the tongue

(d) Suction as you slowly withdraw, moving the tip from side to side

(e) Suction for 15 seconds or less

(f) Reoxygenate casualty after suctioning IAW local SOPs

(g) Observe casualty for:

(i) Hypoxemia

(ii) Color change

(iii) Increased or decreased pulse rate

(iv) Change in breath

Combitube intubation

Combitube

(1) A twin lumen device designed for use in emergency situations and difficult airways.

(2) It can be inserted blindly into the oropharynx and usually enters the esophagus.

(3) It has a low volume inflatable distal cuff and a much larger proximal cuff designed to occlude the oro- and nasopharynx.

(4) Ventilation is achieved through the distal lumen as with a standard ETT.

(5) More commonly the device enters the esophagus and ventilation is achieved through multiple proximal apertures situated above the distal cuff.

(6) In the latter case the proximal and distal cuffs have to be inflated to prevent air from escaping through the esophagus or back out of the oro- and nasopharynx.

(7) The Combitube has been used effectively in cardiopulmonary resuscitation.

(8) It has been used successfully in patients with difficult airways secondary to severe facial burns, trauma, upper airway bleeding and vomiting where there was an inability to visualize the vocal cords.

(9) It can be used in patients whose cervical spine has been immobilized with a rigid cervical collar, though placement may be more difficult. Ventilation does not seem to be affected by the rigid cervical collar if the Combitube can be placed.

(10) Only be used in the adult population, no pediatric sizes are available.

Complications

(1) An increased incidence of sore throat, dysphagia and upper airway hematoma when compared to endotracheal intubation and LMA.

(2) Esophageal rupture is a rare complication but has been described.

(3) Complications may be partially preventable by avoiding over-inflation of the distal and proximal cuffs

(4) Compared to intubation with an endotracheal tube under direct laryngoscopy or using the LMA, the Combitube seems to exert a more pronounced hemodynamic stress.

Contra-indication

(1) Known esophageal disease

Preparation

(1) Test both cuffs for leaks

(a) The pilot balloon of the distal cuff is white and is marked with the number 2

(b) Test the distal cuff by inflating with 15 ml of air

(d) Test the proximal cuff by inflating with 85 ml of air

Sizes Of Combitube

41 Fr	for patients taller than 5ft (152 cm)
37 Fr	patients shorter than 5ft (152 cm)

(1) The bulky design of the 41 Fr can make it more technically difficult to insert

(2) Satisfactory results using the 37 Fr Combitube on taller patients.

Oral Intubation

(1) The combitube can be inserted blindly without the aid of a laryngoscope

(2) Use of a laryngoscope has been reported to facilitate placement of the Combitube,

(3) The laryngoscope aids insertion by forcefully creating a greater space in the hypopharynx.

(4) Induce patient as if for regular intubation.

(5) Patient head position can be neutral.

(6) When direct laryngoscopy is attempted and the vocal cords can be visualized, the Combitube should be placed in the trachea and used as a regular endotracheal tube.

(a) Inflate the distal cuff with just enough air until no leak is present.

(b) Check for bilateral breath sounds over the lungs and confirm endotracheal placement on the capnogram.

(7) If the Combitube is placed blindly, the left hand should elevate the chin while the right hand maneuvers the Combitube.

(8) More space can be created in the hypopharynx by using a laryngoscope with the left hand.

(9) The Combitube should be inserted to such a depth that the upper incisors are between the two black guidelines on the external surface of the tube:

(a) Inflate the distal cuff with 12 ml.

(b) Ventilate through the white connector number 2 and listen for gurgling sounds over the epigastrium or breath sounds over the lungs. If breath sounds are heard over the lungs the Combitube has been placed in the trachea and can be used as a regular ETT as described above after confirmation on the capnogram. If gurgling sounds are heard over the epigastrium, the Combitube is located in the esophagus.

(c) Inflate the proximal cuff with just enough air until either no leak is present or a subjective sensation of increased resistance to cuff inflation is encountered. This is usually achieved by inflating with 50-75 ml of air. This is less than the 85 ml recommended by the manufacturer but has been found to cause less upper airway trauma (1)

(d) Ventilate through the blue connector number 1, listen for breath sounds over the lungs and confirm ventilation on the capnogram.

Troubleshooting Tips

(1) Unable to ventilate patient through blue connector number 1

(a) Make sure the Combitube is not per chance in the trachea.

(b) Attempt to ventilate through connector number 2, if breath sounds are heard over the lungs then the combitube has been placed in the trachea instead of the esophagus.

(2) Unable to ventilate patient through either connector

(a) Confirm that the combitube has been placed in the esophagus by listening for epigastric gurgling sounds while ventilating through connector number 2.

(b) Withdraw the combitube 2-3 cm at a time while ventilating through connector number 1 until breath sounds are heard over the lungs.

(c) The most common cause of this inability to ventilate to ventilate through either connector is an excessive insertion depth of the combitube (relative to the patient).

(d) This will cause obstruction of the glottic opening by the large proximal pharyngeal cuff.

SUMMARY

It is critical that the soldier medic knows how to use and maintain oxygen delivery equipment. Resuscitation measure should never be delayed in order to locate, retrieve, or set up oxygen delivery devices. Having equipment ready, being properly trained on oxygen administration procedures, and having efficient skills in airway management will improve the casualty's respiratory status, thereby, increasing their chances for survival.