Nitrous Oxide and Oxygen Sedation Review

Comprehensive practice flashcards covering the history, guidelines, pharmacokinetics, anatomy, and clinical signs of Nitrous Oxide/Oxygen sedation based on the lecture transcript.

Joseph Priestley

The Englishman who discovered the existence of nitrous oxide and oxygen circa 1775.

Humphrey Davy

The first individual to relate $N_2O$ to dentistry, describing its effects as "overwhelming joy" and the "ideal existence."

Horace Wells

A dentist posthumously recognized as the "Father of Anesthesia" because of his clinical use of nitrous oxide.

Dr. Edmund Andrews

The individual credited with adding oxygen to nitrous oxide in 1868 after recognizing that using $100\%$ $N_2O$ caused blood to be poorly oxygenated.

Minimal sedation (anxiolysis)

A drug-induced state where patients respond normally to verbal commands, typically accomplished with $N_2O$ concentrations less than $50\%$"".

Moderate sedation/analgesia

A drug-induced depression of consciousness where patients respond purposefully to verbal commands, defined when $N_2O$ concentrations are greater than $50\%$"".

Titration

The process of administering a drug incrementally to a specific level or endpoint of sedation.

Pharmacokinetics

The activity or fate of drugs in the body over a period of time, including absorption, distribution, localization in tissues, biotransformation, and excretion.

Pharmacodynamics

The study of the biochemical and physiological effects of drugs and the mechanisms of their actions.

Heat of compression

An increase in temperature caused by opening tank valves too quickly, which can result in a chemical reaction leading to fire or explosion.

Blood-gas coefficient

A measurement indicating how quickly an agent crosses the pulmonary membrane and enters the bloodstream.

Minimum Alveolar Concentration (MAC)

The amount of drug necessary to prevent movement in $50\%$ of subjects responding to surgical incision; for $N_2O$, this is $104\%$ to $105\%$"".

Larynx

The part of the airway where the defensive cough reflex is initiated if irritated.

Carina

The point marking the bifurcation of the trachea into the right and left bronchi which initiates a strong cough reflex if an object passes the larynx.

Alveoli

The $300$ million air sacs in the lungs where the exchange between air and blood takes place.

Tidal volume

The amount of gas in one respiration cycle, which is approximately $500\,mL$ for a healthy, normal-sized adult.

Minute ventilation (volume)

The amount of gas brought into the lungs each minute, typically averaging between $6$ to $7\,L/min$.

Diffusion hypoxia

A decrease in blood oxygen saturation caused by the rapid exit of nitrous oxide upon termination, which can cause postoperative headache, lethargy, and nausea.

Pulse oximeter

A device that uses light wavelengths to measure the amount of oxygen saturation of arterial blood.

Hypoxemic drive

A condition in COPD patients where oxygen levels, rather than carbon dioxide, serve as the stimulus to initiate respiration.

Methionine

A vitamin $B_{12}$-dependent enzyme necessary for DNA synthesis and erythrocyte production that can be inhibited by nitrous oxide interaction.

Malignant hyperthermia

A condition for which $N_2O/O_2$ sedation is NOT considered a trigger and can be safely administered to susceptible individuals.

Appropriate Minimal Sedation (Eyes)

A state where the patient's eye movement is reduced, the blink rate is slower, and the eyes appear glazed or glassy.

Inappropriate Minimal Sedation (Signs)

Signs of over-sedation including detachment from the environment, hallucinations, out-of-body experiences, floating sensations, or slurred speech.