Oxygen Therapy Principles, Hazards, and Delivery Systems

Comprehensive vocabulary flashcards covering the indications, hazards, delivery devices, and medical gases involved in oxygen therapy based on respiratory care lecture material.

Hypoxemia

A low oxygen level in arterial blood that prompts the cardiopulmonary system to increase ventilation and cardiac output.

Tachypnea

A compensatory pulmonary response where the patient breathes faster to bring in more $O_2$.

Tachycardia

A compensatory cardiac response where the heart pumps more blood per minute to deliver more $O_2$ to systemic tissues.

Goal 1 of $O_2$ Therapy (Correct Hypoxemia)

To raise a patient's abnormally low arterial blood oxygen levels.

Goal 2 of $O_2$ Therapy (Decrease Symptoms of Chronic Hypoxemia)

To help relieve clinical symptoms caused by long-term low blood oxygen, such as dyspnea.

Goal 3 of $O_2$ Therapy (Decrease Cardiopulmonary Workload)

To improve blood oxygen levels so the lungs do not have to breathe as hard and the heart does not have to pump as hard to compensate.

Dyspnea

Difficulty breathing or shortness of breath, a prominent symptom associated with chronic hypoxemia.

$$PaO_2$$

A clinical metric obtained from an arterial blood gas (ABG) measuring the partial pressure of oxygen dissolved in arterial blood.

$$SaO_2$$

A measurement indicating the percentage of hemoglobin in arterial blood that is carrying or saturated with oxygen.

Arterial Blood Gas (ABG)

A diagnostic blood sample from an artery used to evaluate oxygenation status, including $PaO_2$.

$PaO_2$ Hypoxemia Threshold

A value less than $60\,\text{mmHg}$, indicating inadequate dissolved oxygen in arterial blood and a need for oxygen therapy.

$SaO_2$ Hypoxemia Threshold

A value less than $90\%$, indicating insufficient hemoglobin saturation with oxygen and a need for oxygen therapy.

Oxygen Fire Hazard

A major physical hazard where oxygen supports combustion, causing combustible materials to ignite and burn more easily around flames or sparks.

Ignition Sources in $O_2$ Therapy

Flames, sparks, smoking, and other potential fire triggers that must be strictly kept away from oxygen.

Hyperoxic Acute Lung Injury (Oxygen Toxicity)

Damage inflicted on pulmonary epithelial and endothelial cells by administering excessive oxygen levels over a prolonged period.

Determinants of Oxygen Toxicity Risk

The severity of the elevated arterial $PaO_2$ and the total duration of patient exposure to that high oxygen level.

Lowest Effective $FiO_2$ Strategy

The clinical practice of using the minimal fraction of inspired oxygen required to maintain adequate oxygenation to minimize cellular lung damage.

$FiO_2$ (Fraction of Inspired Oxygen)

The percentage or fraction of oxygen delivered for the patient to inhale, which directly influences arterial $PaO_2$.

Depression of Ventilation

A hazard occurring when excessive supplemental $O_2$ blunts the hypoxic respiratory drive in COPD patients with chronic hypercapnia, leading to hypoventilation and increased $CO_2$ retention.

Chronic Hypercapnia

A persistent state of elevated arterial carbon dioxide ($CO_2$) commonly found in some COPD patients who depend partly on low $O_2$ to stimulate their breathing.

Retinopathy of Prematurity (Retrolental Fibroplasia)

An ocular disorder where excessive oxygen damages the retinal blood vessels of premature or low-birth-weight infants, leading to abnormal vessel formation, hemorrhage, and scarring.

Population Vulnerable to Retinopathy of Prematurity

Premature or low-birth-weight infants receiving supplemental oxygen.

Complications of Severe Retinopathy of Prematurity

Retinal scarring, retinal detachment, and total blindness resulting from excessive retinal vascular proliferation and bleeding.

Absorption Atelectasis

The collapse of alveoli caused when high concentrations of oxygen wash out alveolar nitrogen and the remaining oxygen rapidly diffuses into the capillary blood, leaving inadequate gas volume.

$FiO_2$ Threshold for Absorption Atelectasis

An inspired oxygen fraction greater than $50\%$, which substantially elevates the risk of alveolar collapse.

Nitrogen Washout

The elimination of inert nitrogen gas from the alveoli when inhaling high concentrations of oxygen, eliminating the structural gas needed to keep alveoli patent.

Low-Flow Oxygen System

A delivery method where the device provides a flow insufficient to meet the patient's entire inspiratory demand, forcing the patient to entrain room air and resulting in a variable $FiO_2$.

Variable $FiO_2$

An delivered oxygen percentage that fluctuates depending on how much ambient room air mixes with the delivered supplemental oxygen during each breath.

Nasal Cannula

A low-flow oxygen delivery device featuring two small prongs inserted into the patient's nares.

Nasal Cannula Flow and $FiO_2$

Flow rates ranging from $1\text{--}6\,\text{Lpm}$ delivering a variable $FiO_2$ between $24\%$ and $44\%$.

Nasal Catheter

A low-flow oxygen delivery tube featuring a single prong inserted deeper into the patient's nose.

Transtracheal Catheter

A low-flow oxygen delivery tube inserted surgically and directly into the trachea.

Reservoir System

An oxygen delivery system that stores oxygen between breaths to provide extra $O_2$ for inhalation during the next inspiratory cycle, resulting in a variable $FiO_2$.

Reservoir Cannula

A specialized oxygen-conserving cannula system that comes in two primary designs: the pendant and the mustache.

Pendant Reservoir Cannula

A reservoir cannula configuration featuring a small oxygen reservoir that hangs below the neck around the patient's upper chest.

Mustache Reservoir Cannula

A reservoir cannula design equipped with an oxygen reservoir bag situated directly under the patient's nose.

Reservoir Cannula Flow and $FiO_2$

Operates at flows of $1\text{--}6\,\text{Lpm}$ to deliver an $FiO_2$ of $24\text{--}44\%$.

Simple Face Mask

A reservoir mask covering the nose and mouth used for short-term oxygenation, notably in fresh post-op and surgical patients.

Simple Face Mask Flow and $FiO_2$

Gas flow of $6\text{--}10\,\text{lpm}$ delivering an $FiO_2$ of $35\text{--}50\%$.

Partial Rebreather Mask

A short-term emergency reservoir mask requiring a minimum flow of $10\,\text{lpm}$ ($FiO_2$ $40\text{--}70\%$) where the patient rebreaths part of their own exhaled gas.

Partial Rebreather Mask Flow and $FiO_2$

Operates with a minimum flow of $10\,\text{lpm}$ and delivers an estimated $FiO_2$ of $40\text{--}70\%$.

Nonrebreathing Mask (NRB)

A reservoir mask covering the nose and mouth equipped with one-way valves designed to prevent the patient from rebreathing exhaled gas during short-term emergency therapy.

Nonrebreathing Mask Flow and $FiO_2$

A minimum flow rate of $10\,\text{L/min}$ delivering an $FiO_2$ of $60\text{--}80\%$ (up to $65\text{--}90\%$).

NRB One-Way Valve Flaps

Valves that allow exhaled gas to escape the mask while preventing exhaled air from entering the reservoir bag during exhalation.

Converting an NRB to a Partial Rebreather

Removing the one-way valve flap from the mask, which permits some exhaled gas to re-enter the reservoir and be rebreathed.

Troubleshooting Reservoir Bag Collapse

If a reservoir bag is deflating during inspiration, the clinician must increase the gas flow to keep the bag inflated.

High-Flow System

An oxygen delivery system providing sufficient total flow to satisfy the patient's entire inspiratory demand, preventing ambient room air entrainment around the device.

Fixed / Controlled $FiO_2$

A precise and unchanging delivered oxygen percentage guaranteed by high-flow devices that supply all gas needed for inhalation.

Air-Entrainment Mask (Venturi Mask)

A high-flow device that mixes oxygen with a controlled amount of entrained room air to deliver a specific, fixed $FiO_2$.

Venturi Mask $FiO_2$ and Patient Population

Delivers a fixed $FiO_2$ of $24\text{--}60\%$, primarily used on patients with COPD or chronic lung disease.

Air-Entrainment Nebulizer

A high-flow system that mixes oxygen with room air to deliver a controlled $FiO_2$ while adding aerosolized humidity to the gas.

Air-Entrainment Jet Adapters

Color-coded entrainment adapters fitted to a nebulizer to deliver specific, calibrated $FiO_2$ concentrations.

Nebulizer Cup

A component of an air-entrainment nebulizer that holds liquid to add humidity and aerosol to inspired gas.

Blending System (Oxygen Blender)

A precision mixer for medical oxygen and compressed medical air allowing the clinician to select any exact $FiO_2$ from $21\%$ to $100\%$.

Heater / Humidifier (HFNC Circuit)

A device component that warms the gas mixture and adds moisture before delivery to the patient's airway.

Heated High-Flow Nasal Cannula (HFNC)

A system combining a blender, heater/humidifier, and nasal prongs to deliver warm, humidified gas at flows meeting the patient's breathing demand.

Hyperbaric Chamber

A sealed medical vessel that administers $100\%$ oxygen under increased atmospheric pressure to drive more oxygen into blood and tissues, commonly used for wound healing.

Carbon Monoxide (CO) Poisoning Treatment

Administration of $100\%\,O_2$ to displace carbon monoxide from hemoglobin and restore tissue oxygen delivery.

Nitric Oxide (NO)

An inhaled therapeutic gas and pulmonary vasodilator that relaxes and widens lung blood vessels to decrease pulmonary vascular resistance.

Heliox

A therapeutic gas mixture of helium and oxygen ($80/20$ or $70/30$) that flows more easily through narrowed airways to decrease the work of breathing.