Overview
Multiplace hyperbaric chambers are large steel vessels that accommodate 2 to 20+ patients at once, along with attending medical staff. The chamber itself is pressurised with air, while patients breathe 100% oxygen through masks, hoods, or endotracheal tubes. This design allows direct medical intervention during treatment.
Multiplace chambers are the configuration of choice for high-acuity hyperbaric medicine. Because the chamber is pressurised with air (not oxygen), attending medical staff — a trained chamber attendant, often a hyperbaric nurse — enter the chamber with the patients and provide direct clinical care at pressure. This matters critically for ventilated or ICU-level patients, emergency decompression sickness treatment, and acute carbon monoxide poisoning management.
Modern clinical multiplace chambers accommodate 4–12 patients plus two attendants in a typical hospital configuration. Larger research and military chambers (US Navy, commercial dive support vessels) can hold 20+ occupants and reach pressures of 6 ATA or deeper. Patients breathe 100% oxygen through built-in breathing systems (BIBS) — hoods, oronasal masks, or endotracheal tubes — with scheduled air breaks every 20–30 minutes to reduce CNS oxygen toxicity risk.
How It Works
The chamber environment is pressurised with air using large compressors. Patients breathe 100% oxygen via mask or hood systems that overboard the exhaled gas, preventing oxygen accumulation inside the chamber. Chamber air is maintained around 21% oxygen; patients receive high-FiO₂ only during inhalation on the breathing system. Attendants breathe chamber air throughout the dive and participate in staged decompression at the end of the session to prevent attendant decompression sickness.
Specifications
| Pressure range | 1.5–6.0 ATA |
|---|---|
| Oxygen purity | 100% O₂ via mask (chamber air pressurised) |
| Session duration | 60–120 minutes |
| Typical cost | $500,000–$2,000,000+ |
Clinical Uses
- Decompression sickness and arterial gas embolism — US Navy Treatment Tables 6 and 6A at 2.8 ATA with potential extension.
- Critical care HBOT — mechanically ventilated patients, severe CO poisoning, acute neurological indications.
- High-throughput wound care — 4–12 patients per session is logistically efficient.
- Group neurological protocols — some long COVID and TBI clinics use multiplace for cost efficiency.
- Dive support — commercial diving and military operations.
Patient Experience
Patients sit upright on chairs or recline on padded benches inside the chamber. They wear a hood or mask connected to the overboard oxygen system. Movement is possible but limited by the breathing apparatus. The chamber interior feels like a small room with other patients and an attendant present. Many patients find multiplace less confining than monoplace. Communication is direct with the attendant throughout the session. Compression and decompression produce ear-fullness sensations similar to flying.
Pros & Cons
Advantages
- Direct in-chamber clinical care — essential for high-acuity patients.
- Higher throughput at scale.
- Less claustrophobia-triggering than monoplace for many patients.
- Can treat patients requiring ventilators, IV lines, and continuous monitoring.
- Larger patients and those with mobility limitations are easier to accommodate.
Limitations
- Substantially higher capital cost ($500K–$2M+).
- Requires in-chamber attendant with specialised training — higher staffing cost.
- Attendant decompression sickness risk requires staged decompression protocols.
- Facility footprint and infrastructure requirements are larger.
- Infection control more complex than monoplace single-patient isolation.
Cost & Access
A clinical multiplace chamber costs $500,000–$2,000,000+ for the chamber alone, with facility costs (reinforced structure, dedicated gas delivery, extensive HVAC and safety systems, chamber room buildout) often doubling the installed cost. Operating costs are higher than monoplace due to in-chamber attendant staffing and higher gas consumption. Multiplace is typically found at larger hospital hyperbaric centres, UHMS Centers of Excellence, and military/commercial dive support facilities.
Key References
- US Navy Diving Manual (Treatment Tables 6, 6A, 7) — foundational multiplace emergency protocols.
- Mathieu D et al. (2017) — European Committee for Hyperbaric Medicine consensus; multiplace clinical practice.
- Weaver LK et al. (2002) — CO poisoning multiplace protocol, NEJM.
Frequently Asked Questions
How many patients fit in a multiplace chamber?
Clinical multiplace chambers typically accommodate 4–12 patients plus 1–2 attendants. Larger research and military chambers can hold 20+ occupants.
Are multiplace chambers safer than monoplace?
Both configurations have excellent safety profiles. Multiplace has the advantage of in-chamber clinical response for medical emergencies but introduces attendant decompression sickness risk requiring staged decompression. The choice is driven by clinical needs, not safety.
Do I need to wear a mask the whole time?
Yes — in multiplace, patients breathe 100% oxygen via a hood or oronasal mask throughout the oxygen-breathing portion of the session, removing the mask only during scheduled 5-minute air breaks.
Is multiplace covered by insurance?
Multiplace HBOT for UHMS-approved indications is covered by CMS/Medicare and most private insurers in the US. Off-label use (TBI, stroke, long COVID) is typically out-of-pocket regardless of chamber configuration.
Research disclaimer: This reference is for educational purposes only. HBOT is a regulated medical treatment that must be administered under appropriate professional supervision. Always consult a qualified physician before considering hyperbaric therapy. Information reflects published research and regulatory guidance available at the time of review.