EMT: Airway, Oxygen and Equipment Checks

In depth

The one-page summary above is what the PDF prints. These sections go further.

Airway protection: consciousness, not the breathing pattern

A patient can have a quiet, clear airway, a normal rate and a good SpO2 and still be unable to protect it. NASEMSO grades responsiveness with AVPU and, in trauma, notes that a GCS of 8 or less makes airway protection more likely to be needed. A patient who responds only to pain has blunted cough and gag reflexes, so the tongue can fall back or vomit can be inhaled at any moment. The recovery position is for a patient who does not respond but breathes normally: it keeps the airway open and lets vomit drain (St John Ambulance). Keep suction ready and recheck responsiveness. Alcohol is never assumed to be the whole story: check glucose and keep head injury on the list.

Stroke can weaken swallowing and the cough reflex in an awake patient. A wet or gurgly voice and drooling are listed by ASHA as signs of swallowing trouble, and dysphagia is reported in 29–64% of stroke patients. Suction the mouth and give nothing by mouth; the hospital screens swallowing before any food or drink. NASEMSO raises the head of the stretcher 15–30 degrees to prevent aspiration when the systolic pressure is over 100, with the neck neutral. Classic teaching also places the patient on the side, weak side down, if secretions keep pooling.

Gurgling means liquid in the upper airway and is cleared first; snoring means the tongue or soft tissue and is opened with a head tilt or jaw thrust; stridor means a narrowed upper airway, which an EMT cannot fix with an adjunct. NASEMSO calls suctioning to limit aspiration a priority.

Suction: which catheter and how

A rigid tonsil-tip (Yankauer) catheter has a wide bore for thick or particulate material in the mouth and oropharynx. In a 2026 bench simulation with a standardized high vacuum it removed more bulk than a 14 French flexible catheter, which could not clear yogurt in the open model, although the flexible catheter left less residual yogurt in the infant mannequin; the authors do not claim clinical superiority. A soft catheter passes through the nose, a nasal airway or a tracheostomy and suits thin secretions. Classic teaching: roll the patient onto the side, insert the rigid tip only as far as you can see, apply suction while withdrawing, keep each pass short and reoxygenate between passes, and scoop out large visible pieces with a gloved finger.

Oral and nasal airways

An oral airway is only for a patient without a gag reflex; it can provoke gagging and aspiration in anyone more responsive, and a nasal airway is the choice when the gag is present (Merck, NASEMSO). Size it against the face: flange at the corner of the mouth, tip at the angle of the jaw. Adults: insert tip toward the palate and rotate 180 degrees, or hold the tongue down with a blade and insert it curve down. Children have a large tongue and a soft palate that is easily injured, so pediatric sources prefer the tongue-blade method with the curve following the tongue and advise against the upside-down rotation in small children. Suction first, never force it, and remove it along its curve if the gag returns. An airway one size larger is not better: a wrong size can itself obstruct the airway.

Ventilation: rate, depth and the bag

Each breath fills the dead space (mouth, pharynx, trachea, bronchi) before any air reaches the alveoli. Merck puts physiologic dead space at 30–40% of a normal tidal volume, so when breaths become very shallow most of each breath is wasted. A rate of 36 with barely moving chest wall moves less useful air than 12 deep breaths, and Merck notes that rates over 28–30 a minute cannot be sustained for long and that a falling tidal volume signals a load the patient is losing to. Watch closely and be ready to assist.

Pulse oximetry measures oxygenation, not ventilation. On a non-rebreather, a few shallow breaths of nearly pure oxygen keep the SpO2 high while carbon dioxide rises; NASEMSO asks for an oxygen delivery method that treats rather than masks the hypercarbia of hypoventilation. For a hypoventilating patient NASEMSO says to support spontaneous respirations: each breath just large enough to see chest rise (about 6–8 mL/kg), at an adult BVM rate of 10–12 a minute (child and infant 20–30). Classic teaching times the squeeze with the patient's own effort and adds breaths in the gaps. Apnea: 1 breath every 6 seconds in an adult, every 2–3 seconds in an infant or child. Fast rates and full-bag squeezes cause gastric inflation, vomiting and aspiration. Two-person, two-thumbs-up mask holds seal best.

The bag self-inflates. LITFL: high-flow oxygen such as 15 L/min, at or above the patient's minute volume, gives close to 100% oxygen; when flow is too low the inlet valve lets in room air. A reservoir that collapses flat after each squeeze at 6 L/min means the bag is drawing room air: turn the flow up. If the cylinder empties mid-carry, keep the same rate and volume; the bag still ventilates with room air, and it goes back on oxygen as soon as possible.

CPAP: keep it on, take it off, keep the intercept

Many states let EMTs apply CPAP under protocol. NASEMSO: once a patient tolerates CPAP, do not break the seal until hospital CPAP is ready or a physician stops it, because loss of pressure causes alveolar collapse and abrupt decompensation. A patient who improves on CPAP still depends on it and still needs the paramedic intercept; NASEMSO asks EMS to request additional resources the condition needs. COPD patients may be adequately treated at an SpO2 of 90%.

Remove CPAP when the patient deteriorates on it (worsening mental status, vomiting, rising EtCO2 if measured) and escalate: high-flow oxygen, bag-mask ventilation if breathing becomes inadequate, ALS. Merck lists barotrauma, including simple and tension pneumothorax, as a complication of noninvasive positive pressure. Sudden one-sided pleuritic pain with lost breath sounds on CPAP suggests a pneumothorax: take CPAP off, give high-flow oxygen, request ALS (needle decompression is outside EMT scope) and transport. Merck contraindications to noninvasive ventilation include vomiting, obtundation, facial trauma, upper airway obstruction and secretions the patient cannot clear. Heart-failure CPAP: EMT By-Complaint Quick Pages.

Special airways in detail

Wired jaw (maxillomandibular fixation): the patient cannot open the mouth, so vomit pools behind the teeth and a suction tip cannot get past them. Surgeons give these patients wire cutters to carry at all times. Children's Wisconsin tells families to cut all the vertical (up-and-down) wires for vomiting or breathing trouble, remove loose pieces so they are not swallowed, and call 911; emergency physicians are taught to cut the vertical wires and heavy vertical elastics and leave the arch bars (EMSJ 2018). None of these sources names a body position. Where protocol allows, turning the patient onto the side so vomit drains is the usual common-sense step (see the recovery position source above), then cut, open the mouth and suction with a rigid tip. Children's Wisconsin also notes that thin vomit often passes between the teeth or out the nose, but it still says to cut when the patient vomits or has trouble breathing. The surgeon re-wires later.

Submandibular space infection (Ludwig angina): usually from the second or third lower molar; signs include drooling, trismus, painful swallowing, a tongue pushed up against the palate and stridor from laryngeal swelling, and it can obstruct the airway within hours (Merck). Stridor is the direct sign the airway is narrowing. Let the patient sit as he chooses, give oxygen if SpO2 falls below 94%, do not agitate him or force an adjunct, request ALS and warn the hospital that intubation may be difficult.

Tongue and mouth bleeding: the tongue has a rich blood supply. NASEMSO makes the airway the priority in facial trauma and, once the spine is cleared, transports sitting up when bleeding, swallowing or secretions are a problem; leaning forward lets blood drain out of the mouth. AAP: firm pressure with gauze for 10 minutes without lifting to check; a cut over 2 cm, across the edge of the tongue or still bleeding after 15 minutes needs a doctor. Merck: children usually need procedural sedation for tongue repair.

Methemoglobinemia: benzocaine and lidocaine are among the commonest causes (Iolascon 2021). Methemoglobin cannot carry oxygen; cyanosis (gray or slate blue) does not improve with oxygen, and standard pulse oximeters give a fixed reading of about 85%. Headache, dyspnea and tachycardia follow as the level rises. Breathing that is adequate is not assisted; high-flow oxygen stays on for the normal hemoglobin that remains. Methylene blue is the hospital antidote and is outside EMT scope, so bring the product, report the exposure and transport.

Oxygen cylinders and regulators

Duration in minutes = usable pressure × cylinder constant ÷ flow, where usable pressure is the gauge reading minus the safe residual. RT Zone lists D 0.16, E 0.28, M 1.36 and H 3.14 L/psig, notes a full cylinder holds about 2,000–2,200 psig and suggests changing near 500 psig. ProTrainings (a UK oxygen course page) and Omni Calculator list M as 1.56, and ProTrainings subtracts a 200 psi residual, which is also what EMT texts and exam items use; the two sources differ, so use whatever constant and residual the protocol or question gives. Examples: D at 1,800 psi, 2 L/min: (1,800 − 200) × 0.16 ÷ 2 = 128 min. M at 2,000 psi, two masks at 15 L/min: 1,800 × 1.56 ÷ 30 ≈ 94 min, short of a 100-minute trip. D at 1,000 psi, 15 L/min: 800 × 0.16 ÷ 15 ≈ 8.5 min, so switch to onboard oxygen before leaving. Common errors: forgetting the residual, the second patient's flow or the right constant. Turning a non-rebreather down to stretch a cylinder trades a supply problem for hypoxemia.

Pin index safety system: on E-size and smaller cylinders, pins on the regulator yoke must match holes on the valve in a gas-specific pattern, so a regulator for another gas does not seat; the sealing washer must be present and intact (RT Zone). It reduces but does not eliminate wrong-gas errors, and cylinder color is not definitive, so read the label. Never force or shim a mismatched regulator.

Bourdon gauge flowmeter: it reads pressure behind a fixed orifice, so a kink or pinch downstream leaves the dial at the set flow while little or no oxygen arrives (WisTech, RT Zone). It is used on cylinders because it works in any position; a Thorpe tube must stay upright. A flat reservoir at a normal rate means trace the tubing from regulator to mask.

Requalification (49 CFR 180.209 and 180.205): steel DOT 3A and 3AA cylinders are retested every 5 years, or every 10 years when a five-pointed star follows the test date and the cylinder meets the rule's conditions for a listed gas such as oxygen; no cylinder may be filled unless requalified and marked, although one filled before the date came due may be used until empty. An overdue cylinder is tagged for retest before refilling.

Oil, fire and storage (29 CFR 1910.253): keep cylinders, valves, regulators and hoses free of oil and grease, do not handle them with oily hands or gloves, and regulator gauges are marked USE NO OIL. A sticking regulator is swapped for a spare and repaired, never lubricated. Stored oxygen cylinders are kept 20 ft from fuel-gas cylinders and combustibles, especially oil or grease, or separated by a noncombustible barrier at least 5 ft high with a half-hour fire rating. Cylinders are stored upright, chained or held so they cannot fall (WisTech). At home, oxygen stays at least 6 ft from flames and heat sources (MedlinePlus); during a power outage, generators run outside and at least 20 ft from windows and doors (CDC).

Liquid oxygen: the liquid and the parts carrying it are cold enough to cause frostbite (American Lung Association). Because it slowly evaporates, a portable unit is always kept upright; if it tips it may hiss and release vapor, so stand it up at once, and keep it in a ventilated area (WisTech). The patient breathes from the ambulance supply; if the unit comes along it rides upright and secured per agency policy.

Defibrillation: an arc in oxygen-enriched air can start a fire. Before a shock, take off any oxygen mask, nasal cannula or bag-valve mask and place it at least 1 m from the chest; a bag attached to an advanced airway can stay connected (RCUK 2025). Resume compressions immediately after the shock. AED details: BLS, High-Quality CPR and Choking.

Shift checks

Masks must cover the nose and mouth and seal at the cheeks and chin, and NASEMSO says pediatric airway management needs appropriately sized tools and adjuncts and that a method for choosing the size should be available to all EMS clinicians; the 2020 joint position statement on essential ambulance equipment (abstract read) sorts equipment into BLS and ALS levels, and its abstract does not name an infant mask. The out-of-service rule is classic agency practice: a missing infant mask is fixed before the unit goes in service, so tell dispatch and the supervisor and get one from another unit or station. Inverting an adult mask or relying on a pocket mask is not a plan for a known gap.

Classic teaching: the mounted suction serves the patient compartment; the portable unit travels with the airway kit to the bedroom, stairwell or wrecked car where vomiting and seizures happen. A portable unit that dies off its charger takes the crew out of service until it is replaced.

Glucometer: FDA suggests a control solution test each time a new container of strips is opened, and the result must fall within the range printed on the strip vial. Out of range means the strips, solution or meter is faulty; keep the vial closed and store strips as directed. Because EMTs give oral glucose on these readings, the meter is not used until a repeat test with good strips passes.

Helping with the patient's own medicine

Inhalers: the Advair HFA label states fluticasone-salmeterol is not indicated for acute bronchospasm, should not be started during a rapidly deteriorating episode, and that acute symptoms are treated with an inhaled short-acting beta2-agonist. Assist with the patient's own albuterol after confirming it is prescribed to the patient and in date, give oxygen toward 94–98%, reassess speech, rate and SpO2, and transport.

Epinephrine auto-injector: confirm the right patient (prescribed to them), drug, dose (EpiPen 0.3 mg for about 30 kg or more, 0.15 mg for 15–30 kg; NASEMSO uses 25 kg as the cut-off), route (anterolateral thigh, through clothing if needed; never buttock, hands, feet or digits), expiry date, and that the solution in the window is clear and colorless, then document the time and response. Reading each item aloud to a partner catches errors.

Exam pearls

• Responds only to pain: cannot protect the airway, whatever the SpO2
• Gurgling: suction first; rigid tip for chunky vomit, only as deep as you can see
• Oral airway: no gag, mouth corner to jaw angle; children curve down with a tongue blade
• Normal SpO2 on oxygen does not prove ventilation
• BVM: 15 L/min keeps the reservoir full; an empty cylinder does not stop ventilation
• CPAP: keep it on while it works, take it off when the patient worsens
• Cylinder minutes: (psi − residual) × constant ÷ total flow
• Bourdon gauge reads pressure, not delivered flow
• Pins that do not match mean the wrong gas; no oil on oxygen equipment ever
• Oxygen 1 m from the chest before a shock