100+ Free ABPM Undersea and Hyperbaric Medicine Practice Questions
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Boyle's law states that at constant temperature the pressure and volume of a gas are inversely related (P1V1 = P2V2). A diver exhales a 6-L lungful at the surface (1 ata). What volume would that same gas occupy if the diver descended to 99 fsw (4 ata) without any further breathing?
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Key Facts: ABPM Undersea and Hyperbaric Medicine Exam
~200
Total MCQ Items
ABPM UHM Subspecialty Certification Exam
~6 hr
Total Exam Time
1-day computer-based test including breaks
14
UHMS-Approved Indications
UHMS Indications Manual (14th edition)
$2,100
2026 Subspecialty Fee
ABPM UHM subspecialty certification
1 yr
ACGME UHM Fellowship
Preferred eligibility pathway
TT6
First-Line Recompression
US Navy Treatment Table 6 for AGE & serious DCS
The ABPM UHM subspecialty exam is a 1-day computer-based test at Pearson VUE with approximately 200 single-best-answer MCQs over roughly 6 hours including breaks. The 2026 blueprint emphasizes UHMS-approved hyperbaric indications (~18-22%), gas physics and physiology (~12-15%), DCS (~12-14%), AGE (~8-10%), oxygen toxicity and nitrogen narcosis (~8-10%), fitness to dive (~8-10%), CO poisoning (~6-8%), wound care/diabetic foot ulcer with TcPO2 (~6-8%), chamber operations (~8-10%), complications and contraindications (~6-8%), recompression treatment tables TT5/TT6 (~6-8%), and adjunctive therapy/special topics (~5-7%). Subspecialty certification fee ~$2,100; eligibility requires active primary ABMS certification plus ACGME UHM fellowship or qualifying practice pathway.
Sample ABPM Undersea and Hyperbaric Medicine Practice Questions
Try these sample questions to test your ABPM Undersea and Hyperbaric Medicine exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.
1Boyle's law states that at constant temperature the pressure and volume of a gas are inversely related (P1V1 = P2V2). A diver exhales a 6-L lungful at the surface (1 ata). What volume would that same gas occupy if the diver descended to 99 fsw (4 ata) without any further breathing?
2In seawater, what depth corresponds to one atmosphere (1 ata) of gauge pressure?
3Which gas law explains the increased dissolved nitrogen burden in tissues at depth?
4Which gas law underlies the calculation of inspired oxygen partial pressure as depth increases?
5A patient is breathing 100% oxygen at 3 ata in a hyperbaric chamber. What is the inspired PO2 (approximate, ignoring water vapor)?
6At 3 ata of 100% oxygen, how much oxygen is dissolved in plasma (using 0.003 mL O2/dL/mmHg PaO2)?
7The US Navy Workman/Schreiner Haldanian model uses how many theoretical tissue compartments to track inert-gas loading?
8A 'fast tissue' compartment with a 5-minute half-time will be approximately what percent saturated after 25 minutes at depth?
9Which patient presentation is most consistent with Type I (pain-only) decompression sickness?
10Which is the most common spinal cord level affected by Type II decompression sickness?
About the ABPM Undersea and Hyperbaric Medicine Exam
The ABPM Undersea and Hyperbaric Medicine (UHM) subspecialty certification validates physician expertise in dive medicine and hyperbaric oxygen therapy (HBO2). Scope includes gas physics under pressure (Boyle, Dalton, Henry), tissue gas kinetics (Haldanian compartments), decompression sickness (Type I and II) and arterial gas embolism, oxygen toxicity (CNS Paul Bert effect with seizures at PO2 >1.6 ata; pulmonary Lorraine Smith effect), nitrogen narcosis, fitness-to-dive evaluation, the 14 UHMS-approved hyperbaric indications (CO poisoning, refractory osteomyelitis, soft tissue and bone radionecrosis, diabetic foot ulcers Wagner ≥3, crush injury, idiopathic SSNHL within 14 days, central retinal artery occlusion, intracranial abscess, severe anemia, gas gangrene, necrotizing soft tissue infection, thermal burns, compromised flaps, AGE, DCS), monoplace vs multiplace chamber operations, NFPA 99 fire safety, complications and contraindications (untreated pneumothorax absolute), wound care principles with transcutaneous oximetry (TcPO2), and US Navy Treatment Tables 5 and 6. ABPM administers the exam on the Preventive Medicine pathway; ABEM, ABFM, ABIM, and ABA also administer the same examination.
Questions
200 scored questions
Time Limit
1-day CBT (~6 hours including breaks)
Passing Score
Criterion-referenced scaled score (modified Angoff) common to ABMS sponsoring boards
Exam Fee
~$2,100 subspecialty certification fee (ABPM 2026) (American Board of Preventive Medicine (ABPM) / Pearson VUE)
ABPM Undersea and Hyperbaric Medicine Exam Content Outline
Gas Physics & Physiology Under Pressure
Gas laws (Boyle P1V1=P2V2, Charles, Dalton partial pressures, Henry solubility, Gay-Lussac), pressure units (atm, msw, fsw, ata — 33 fsw or 10 msw seawater = 1 ata gauge), oxygen content (CaO2 = 1.34×Hgb×SaO2 + 0.003×PaO2 — at 3 ata 100% O2 dissolved O2 alone covers basal needs), alveolar gas equation under pressure, Haldanian half-time tissue compartments and US Navy 6-tissue model, nitrogen on/off-gassing kinetics, supersaturation and bubble formation.
Decompression Sickness (DCS)
Type I (musculoskeletal pain-only 'bends', cutis marmorata skin marbling, lymphatic) vs Type II (neurological — spinal cord most commonly low thoracic, vestibular, cardiopulmonary 'chokes'). Risk factors (depth/time/repetitive dives, PFO with right-to-left shunt, dehydration, exercise post-dive, flying after diving). Treatment: surface 100% oxygen, hydration, definitive recompression with US Navy Treatment Table 6; mild Type I may resolve with TT5.
Arterial Gas Embolism (AGE) & Pulmonary Barotrauma
Pulmonary overpressurization syndrome (POPS) on rapid ascent with closed glottis or air-trapping (asthma) → alveolar rupture → AGE, pneumomediastinum, pneumothorax. AGE classically presents within 10-15 minutes of surfacing with stroke-like neurologic deficits or LOC. Treatment: immediate recompression TT6, neutral supine positioning (Trendelenburg no longer recommended), 100% surface oxygen pre-recompression, IV hydration.
Oxygen Toxicity & Nitrogen Narcosis
CNS oxygen toxicity (Paul Bert effect — convulsions at PO2 >1.6 ata; mnemonic VENTID-C: Visual changes, Ear ringing, Nausea, Twitching, Irritability, Dizziness, Convulsions). Pulmonary oxygen toxicity (Lorraine Smith effect — UPTD/CPTD tracked by Repex; substernal pain, decreased VC). Nitrogen narcosis (Martini's law: each 50 fsw ≈ 1 martini; significant >100 fsw, incapacitating >300 fsw). HPNS at very deep heliox dives.
Dive Medicine Evaluation & Fitness to Dive
Absolute contraindications (untreated pneumothorax, bullous lung disease, uncontrolled seizures, intracardiac right-to-left shunt with prior DCS). Relative contraindications (asthma — case-by-case with PFTs and methacholine challenge; PFO; insulin-dependent diabetes; psychiatric instability). Pre-dive medical evaluation (PADI/DAN), return-to-dive timing post-DCS/AGE/surgery, flying after diving (≥12 hr single dive, ≥18 hr repetitive per DAN).
UHMS-Approved Hyperbaric Indications
The 14 UHMS-approved indications: AGE; CO poisoning (with or without cyanide); clostridial myonecrosis (gas gangrene); crush injury, compartment syndrome, acute traumatic ischemia; DCS; enhancement of healing in selected problem wounds (diabetic foot ulcer Wagner ≥3); severe anemia; intracranial abscess; necrotizing soft tissue infection; refractory osteomyelitis; delayed radiation injury (soft tissue and bone — ORN of mandible Marx 20/10 or 30/10 protocol); compromised grafts and flaps; acute thermal burns; idiopathic SSNHL within 14 days; central retinal artery occlusion.
Carbon Monoxide Poisoning
CO binds Hgb 240× affinity over O2, shifts ODC left (impaired O2 delivery), inhibits cytochrome oxidase, drives lipid peroxidation. COHb t1/2 — room air ~5 hr, 100% NRB ~60-90 min, HBO2 at 2.8-3.0 ata ~20-30 min. HBO2 indications: any LOC, neurologic signs, cardiac ischemia, pregnancy with COHb >15%, COHb >25%, persistent symptoms after NBO. Reduces delayed neurocognitive sequelae (Weaver NEJM 2002 — 3 sessions within 24 hr at 3-2-2 ata).
Wound Care & Diabetic Foot Ulcer
Wagner classification (0 intact skin, 1 superficial, 2 to tendon/capsule, 3 deep abscess or osteomyelitis, 4 partial-foot gangrene, 5 whole-foot gangrene). HBO2 indicated for Wagner ≥3 after standard care (offloading, debridement, infection control, glycemic optimization, revascularization) fails. TcPO2: in-chamber TcPO2 >200 mmHg at 2.0-2.4 ata predicts response; periwound TcPO2 <30 mmHg on air with rise >100 mmHg in chamber favorable.
Hyperbaric Chamber Operations & Safety
Monoplace (single patient, 100% O2 pressurization, 2.0-3.0 ata typical) vs multiplace (chamber air + BIBS mask 100% O2, attendants inside, deeper treatments and emergent care possible). NFPA 99 fire safety: 100% cotton garments only, no electronics/petroleum products/hand warmers. Atmospheric monitoring (O2 <23.5% in air-pressurized chamber). Communication, treatment table selection, ventilator/IV pump compatibility, ear equalization techniques (Frenzel, Valsalva), tympanostomy tubes for unconscious patients.
Complications & Contraindications
Absolute contraindication: untreated pneumothorax (must be decompressed or chest tube placed first). Relative: bleomycin (pulmonary fibrosis), doxorubicin, cisplatin, disulfiram, mafenide acetate, COPD with bullae, claustrophobia, pacemakers/ICDs (must be pressure-tested). Complications: middle ear barotrauma (most common — TEED grading), sinus barotrauma, oxygen seizures (~1:10,000 treatments), pulmonary O2 toxicity, reversible myopia, cataract progression, confinement anxiety, hypoglycemia in diabetics.
Recompression Treatment Tables
US Navy Treatment Table 6 (TT6): 60 fsw (2.8 ata) breathing 100% O2 with air breaks, total ~4 hr 45 min standard duration — first-line for AGE, serious DCS, residual symptoms after TT5. TT5: 60 fsw 100% O2 for milder Type I DCS responsive within 10 min at depth, ~2 hr 15 min total. TT4 and TT7 for severe/protracted cases. TT9 for adjunctive HBO2 in non-diving emergencies. Recompression initiated even with delayed presentation (benefit out to >24-48 hr).
Adjunctive Therapies & Special Topics
Lidocaine adjunct considered for AGE/DCS neuroprotection in some protocols. tPA generally NOT given prior to HBO2 for AGE/DCS — recompression is the definitive therapy and should not be delayed for thrombolytics. CRAO with HBO2 within 24 hr; pediatric considerations; pregnancy and HBO2 (not contraindicated for CO poisoning — fetal COHb persists longer than maternal). Repex unit tracking for cumulative pulmonary O2 dose, treatment outcomes registries.
How to Pass the ABPM Undersea and Hyperbaric Medicine Exam
What You Need to Know
- Passing score: Criterion-referenced scaled score (modified Angoff) common to ABMS sponsoring boards
- Exam length: 200 questions
- Time limit: 1-day CBT (~6 hours including breaks)
- Exam fee: ~$2,100 subspecialty certification fee (ABPM 2026)
Keys to Passing
- Complete 500+ practice questions
- Score 80%+ consistently before scheduling
- Focus on highest-weighted sections
- Use our AI tutor for tough concepts
ABPM Undersea and Hyperbaric Medicine Study Tips from Top Performers
Frequently Asked Questions
What is the ABPM Undersea and Hyperbaric Medicine certification?
The Undersea and Hyperbaric Medicine (UHM) subspecialty certification validates physician expertise in dive medicine, hyperbaric oxygen therapy (HBO2), and treatment of dysbaric injuries. ABPM is one of several ABMS sponsoring boards (along with ABEM, ABFM, ABIM, and ABA) that administer the same UHM examination. Scope includes gas physics under pressure, decompression sickness, arterial gas embolism, oxygen toxicity (CNS and pulmonary), nitrogen narcosis, fitness-to-dive evaluation, the 14 UHMS-approved hyperbaric indications, monoplace and multiplace chamber operations, NFPA 99 fire safety, complications and contraindications, wound care with transcutaneous oximetry, and US Navy Treatment Tables 5 and 6. Certification supports practice in commercial/recreational dive medicine, hospital-based hyperbaric units, wound care centers, and academic UHM programs.
Who is eligible to take the ABPM UHM exam?
Candidates must hold an MD, DO, or equivalent doctoral medical degree with an unrestricted license AND active primary ABMS certification (ABPM, ABEM, ABFM, ABIM, ABA, or other sponsoring board). Most candidates qualify by completing a 1-year ACGME-accredited UHM fellowship (preferred pathway). A practice pathway accepting documented UHM clinical experience and CME has historically been available; eligibility criteria evolve and should be confirmed on the sponsoring board's website at the time of application.
What is the format of the ABPM UHM exam?
The exam is a 1-day computer-based test administered at Pearson VUE test centers, comprising approximately 200 single-best-answer multiple-choice questions over roughly 6 hours including breaks. Items include vignettes covering gas physics calculations, dive-profile interpretation, decompression illness presentations and triage to TT5 vs TT6, fitness-to-dive scenarios, UHMS-indication selection, chamber operations and safety, drug interactions, and TcPO2 interpretation for diabetic foot ulcers. Question stems align with the published UHM content outline.
How much does the 2026 ABPM UHM subspecialty exam cost?
The 2026 ABPM UHM subspecialty certification fee is approximately $2,100 (verify current figure on the ABPM site). Cancellation and refund policies follow ABPM's posted schedule with decreasing refunds as the exam date approaches. Continuing Certification fees apply during the 10-year cycle (ABPM is transitioning to a longitudinal assessment model). Retakes within the eligibility window require re-registration and full fee payment, and candidates must maintain primary ABMS certification.
When is the 2026 UHM exam administered?
ABPM typically administers the UHM subspecialty exam during a fall testing window at Pearson VUE. Application windows generally open in the spring with submission deadlines in early summer. After approval, candidates schedule a specific appointment with Pearson VUE within the published window. Other sponsoring boards (ABEM, ABFM, ABIM, ABA) administer the same exam on similar cycles. Exact 2026 dates should be confirmed on the ABPM exam information page.
How is the UHM exam scored?
The exam uses criterion-referenced scoring with the passing standard set by subject-matter experts using the modified Angoff method. A candidate's pass/fail result depends on performance relative to the fixed cut-score, not relative to other candidates. Score reports include subdomain performance breakdown to guide future learning. Results are typically released several weeks after the testing window closes. The cut-score and standard-setting process are common across the ABMS sponsoring boards.
What are the highest-yield topics for the UHM exam?
Highest-yield topics include the 14 UHMS-approved hyperbaric indications and the evidence supporting each (Weaver CO protocol with 3-2-2 ata sessions, Marx 20/10 or 30/10 ORN protocol, Wagner ≥3 with TcPO2 for diabetic foot ulcer, ISSNHL within 14 days, CRAO within 24 hr); gas physics under pressure (Boyle, Dalton, Henry; alveolar gas equation; oxygen content); DCS Type I vs II triage to TT5 vs TT6; AGE diagnosis and immediate recompression; CNS oxygen toxicity threshold (PO2 >1.6 ata) with VENTID-C; nitrogen narcosis (Martini's law); absolute contraindication of HBO2 in untreated pneumothorax; bleomycin/doxorubicin/cisplatin/mafenide drug cautions; monoplace vs multiplace operations and NFPA 99 fire safety; flying-after-diving rules.
How should I study for the UHM exam?
Use a 6-12 month structured plan during and after UHM fellowship. Lead with gas physics and diving physiology (Bove's Diving Medicine, US Navy Diving Manual Rev 7). Layer in dysbaric injuries (DCS, AGE, oxygen toxicity, nitrogen narcosis) with treatment table indications. Then master each of the 14 UHMS-approved indications with current evidence (UHMS Indications Manual, 14th edition). Add chamber operations, NFPA 99 safety, drug interactions, and wound care/TcPO2 interpretation. Integrate UHMS Annual Scientific Meeting content, Hyperbaric Oxygen Therapy: A Committee Report (UHMS), and a structured board review course. Complete high-volume MCQs with timed practice and 2-3 full-length mock exams.