Oxygen Therapy and Ventilatory Support - NREMT AEMT Level

What SpO $_2$ range is commonly targeted during oxygen therapy for most adults?

SpO $_2$ about $94\%$ to $99\%$ . This range ensures adequate oxygenation without risking oxygen toxicity in stable adult patients not at risk for hypercapnia.
What is the minimum oxygen flow rate for a simple face mask to prevent CO $_2$ rebreathing?

At least $6$ L/min. Lower flows allow CO2 accumulation in the mask's dead space, increasing rebreathing and potential hypercapnia.
What is the normal oxygen concentration in room air at sea level?

Approximately $21\%$ oxygen. Room air consists primarily of nitrogen (78%) and oxygen (21%), with trace gases making up the remainder at standard atmospheric pressure.
What device delivers the highest and most reliable FiO $_2$ for a spontaneously breathing patient?

Nonrebreather mask at high flow. It minimizes room air dilution through one-way valves and a reservoir, achieving up to 90-100% FiO2 in optimal conditions.
What is the typical oxygen flow rate for a nonrebreather mask in an adult?

$10$ to $15$ L/min (keep reservoir inflated). High flow maintains reservoir inflation to deliver near 100% FiO2 by preventing room air entrainment during inhalation.
What SpO $_2$ range is commonly targeted for patients at risk of CO $_2$ retention (COPD)?

SpO $_2$ about $88\%$ to $92\%$ . Lower targets prevent suppression of hypoxic respiratory drive in chronic hypercapnic patients, balancing oxygenation with CO2 retention risks.
Which clinical presentation is a classic indication for CPAP in the prehospital setting?

Acute cardiogenic pulmonary edema with distress. CPAP reduces preload and afterload while improving oxygenation, alleviating respiratory distress in pulmonary edema from heart failure.
What is the recommended adult BVM ventilation rate when a pulse is present?

About $1$ breath every $5$ to $6$ seconds. This rate (10-12 breaths/min) maintains adequate oxygenation and CO2 elimination without causing hyperventilation in patients with a pulse.
What is the most appropriate immediate intervention for apnea with a pulse?

BVM ventilations with oxygen. Apnea requires immediate positive pressure ventilation to oxygenate and ventilate until spontaneous breathing resumes or advanced care is available.
Which airway adjunct is generally preferred when the gag reflex is intact?

Nasopharyngeal airway (NPA). NPA is better tolerated in semi-conscious patients as it bypasses the oral cavity and does not stimulate the gag reflex as strongly.
Which oxygen delivery device is preferred when a precise FiO $_2$ is needed (for example, COPD)?

Venturi mask (air-entrainment mask). It uses adapters to entrain specific air-oxygen ratios, providing controlled FiO2 (24-50%) ideal for patients sensitive to high oxygen levels.
Which finding is the most reliable indicator of hypoxemia in the field?

Low pulse oximetry (SpO $_2$ ) with clinical correlation. Pulse oximetry measures oxygen saturation noninvasively, but must be interpreted alongside clinical signs like cyanosis or altered mental status for accuracy.
What is the primary clinical goal of oxygen therapy in a hypoxic patient?

Correct hypoxemia by improving oxygenation. Oxygen therapy aims to increase alveolar oxygen levels to enhance tissue oxygenation in patients experiencing low blood oxygen saturation.
Identify the most likely cause if SpO $_2$ is low but the patient has cold hands and poor waveform.

Poor perfusion causing unreliable pulse oximetry. Peripheral vasoconstriction from shock or cold reduces pulsatile flow, leading to inaccurate SpO2 readings despite potentially normal oxygenation.
What is the recommended pediatric BVM ventilation rate when a pulse is present?

About $1$ breath every $3$ to $5$ seconds. Children have higher metabolic rates and oxygen demand, requiring faster ventilation (12-20 breaths/min) to match physiological needs.
What is the key setup check for a nonrebreather mask before applying it to the patient?

Reservoir bag inflated and one-way valves functioning. These ensure the device prevents exhaled air re-entry and maintains high FiO2 by storing oxygen for inhalation.
Which airway adjunct is contraindicated in a patient with an intact gag reflex?

Oropharyngeal airway (OPA). OPA insertion can trigger gagging or vomiting in responsive patients, risking aspiration, so it's reserved for unconscious individuals without reflexes.
Find the best immediate correction if BVM ventilations produce no chest rise and high resistance.

Reposition airway and reseal mask; consider obstruction. Inadequate chest rise indicates failed ventilation, often due to poor seal, airway malposition, or blockage requiring prompt troubleshooting.
What is the most accurate method to confirm and continuously monitor ventilation effectiveness in the field?

Waveform capnography (ETCO $_2$ trending). It provides real-time graphical ETCO2 monitoring, confirming tube placement and assessing ventilation adequacy more reliably than colorimetry.
What is the typical oxygen flow rate for a simple face mask in an adult?

$6$ to $10$ L/min. This range delivers 40-60% FiO2, suitable for moderate hypoxemia, but requires minimum flow to flush exhaled CO2.
What is the appropriate ventilation rate for an adult with an advanced airway during CPR?

$1$ breath every $6$ seconds (about $10$ /min). During CPR with an advanced airway, asynchronous ventilations at this rate support circulation without interrupting compressions.
What is the typical oxygen flow rate range for a nasal cannula in an adult?

$1$ to $6$ L/min. This flow provides low to moderate FiO2 (24-44%) comfortably for patients with mild hypoxemia who can breathe spontaneously.
Which option is most appropriate for a patient breathing $28$ /min with shallow breaths and fatigue?

Assist ventilations with BVM and oxygen. Tachypnea with shallow breaths and fatigue signals impending respiratory failure, necessitating assisted ventilation to improve gas exchange.
What is the expected duration of each ventilation to reduce gastric inflation and barotrauma?

Deliver each breath over about $1$ second. Slow delivery minimizes peak inspiratory pressure, reducing risks of gastric distension and lung injury from excessive volume or pressure.
Which condition is an absolute contraindication to CPAP in most EMS protocols?

Apnea or respiratory arrest. CPAP requires spontaneous breathing to be effective; apnea necessitates ventilatory support like BVM to prevent hypoxia and hypercapnia.

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