DMT flashcards

31 cards. Read the term and the definition here. The deck at the top of this page is optional.

Type I decompression sickness

DCS limited to musculoskeletal pain, cutaneous symptoms (mottling, itching), and lymphatic involvement, without neurological or cardiopulmonary features.

Type II decompression sickness

DCS with neurological, cardiopulmonary, or vestibular involvement, including weakness, sensory loss, cough, chest pain, or vertigo; requires urgent recompression.

Arterial gas embolism

Gas bubbles entering the arterial circulation, usually from pulmonary barotrauma, causing sudden focal neurological deficits, seizure, or loss of consciousness within minutes of surfacing.

Nitrogen narcosis

Reversible impairment of judgment, coordination, and reaction time from elevated nitrogen partial pressure at depth, typically noticeable around 30 meters and deeper on air.

Oxygen toxicity CNS

Seizures, visual disturbance, tinnitus, nausea, and twitching caused by high oxygen partial pressure, especially above 1.6 atm; managed by reducing PO2 and depth.

Alveolar oxygen partial pressure

The oxygen pressure in alveoli, approximated as inspired PO2 minus arterial CO2 pressure divided by respiratory quotient; low values cause hypoxemia regardless of oxygen fraction.

Immersion pulmonary edema

Fluid accumulation in the lungs triggered by immersion, cold, and exertion, causing dyspnea, cough, and hypoxemia; can mimic drowning and requires immediate removal from water.

Haldane tissue half-time

The time for a tissue compartment to reach half of the change toward a new inert gas tension; fast compartments govern short deep exposures, slow compartments govern saturation.

HBOT session parameters

Typical treatment uses 2.0-2.5 atm abs for 60-120 minutes with air breaks of about 5 minutes every 20-30 minutes to reduce oxygen toxicity risk.

Carbon monoxide HBOT

Hyperbaric oxygen displaces carboxyhemoglobin, shortening its half-life from hours to roughly 20-30 minutes at 2.5-3 atm abs, and reduces reperfusion injury.

Crush injury HBOT

HBOT for crush injury and compartment syndrome reduces edema, improves oxygen delivery to ischemic tissue, and supports wound healing; used as an adjunct to surgery.

Osteoradionecrosis HBOT

Hyperbaric oxygen is used for delayed radiation injury and osteoradionecrosis to improve tissue oxygenation, promote angiogenesis, and support healing of irradiated bone and soft tissue.

HBOT contraindication pneumothorax

Untreated pneumothorax is an absolute contraindication because gas expansion during decompression can cause tension pneumothorax; it must be treated before compression.

Dissolved oxygen Henry law

Dissolved oxygen in plasma rises about 0.003 mL O2 per dL per mmHg PO2, so at 3 atm abs it can meet resting metabolic needs without hemoglobin.

Middle ear barotrauma

The most common compression injury in hyperbaric and diving settings, caused by failure to equalize middle-ear pressure; presents with pain, hearing loss, and tympanic hemorrhage.

Chamber fire safety

Hyperbaric chambers require strict ignition control, limits on combustibles, electrical safety, and atmosphere monitoring because oxygen-enriched atmospheres greatly increase fire risk and burn rate.

Otoscopy in diving medicine

Examination of the tympanic membrane to detect retraction, hemorrhage, effusion, or perforation from barotrauma, guiding equalization advice and fitness to dive or compress.

Dive profile reconstruction

Reconstructing depth-time history, surface intervals, and ascent rates from computer data or diver recall to guide recompression decisions when the original profile is incomplete.

Carboxyhemoglobin measurement

Blood testing that quantifies carbon monoxide bound to hemoglobin; used to confirm CO poisoning and monitor response, though symptoms may not correlate with level.

In-water recompression

Returning a symptomatic diver to depth in water as a field treatment for DCS; reserved for remote settings with trained support, since standard care is surface oxygen and chamber transport.

Device behavior under pressure

Gas-filled cuffs and balloons expand on ascent and can rupture, while fluid-filled lines compress and may occlude; plan device management before hyperbaric exposure.

Neurological exam for DCS

Serial assessment of cranial nerves, motor strength, sensation, coordination, gait, and mental status to detect and track neurological decompression sickness and response to treatment.

Ascent rate limit

Recreational ascent is limited to about 9-10 meters per minute (30 ft/min), with a 3-5 minute safety stop at 3-6 meters after no-decompression dives.

Nitrox oxygen analysis

Measuring the oxygen fraction of an enriched-air mix before each dive and setting depth limits based on maximum oxygen partial pressure, commonly 1.4 atm for working dives.

Out-of-gas procedure

Signal the buddy, switch to a backup gas source, and ascend at the standard rate without breath-holding to avoid pulmonary barotrauma; never ascend while holding breath.

Emergency action plan diving

A documented plan identifying the nearest hyperbaric facility, transport time, communication chain, and emergency contacts, rehearsed before operations begin.

Pre-dive safety check

Verification of gas analysis and labeling, regulator function, BCD and suit integrity, weight release, and team signals before entering the water.

ASME PVHO-1

A standard for pressure vessels for human occupancy covering design, fabrication, inspection, and testing, including viewports and penetrators used in hyperbaric chambers.

NFPA 99 hyperbaric chapter

A health care facilities standard addressing fire safety, electrical classification, and oxygen handling in hyperbaric facilities, including limits on combustibles in oxygen-enriched atmospheres.

UHMS indications

The Undersea and Hyperbaric Medical Society publishes the recognized list of hyperbaric oxygen indications and facility accreditation criteria used by clinicians and payers.

IMCA diving standards

International Marine Contractors Association guidance for commercial diving operations covering safety management, competence, and medical fitness requirements.