A multiplace hyperbaric chamber treats multiple patients simultaneously in a pressurized air environment, with oxygen delivered via mask or hood rather than filling the chamber with pure O₂. This configuration allows clinical staff. Nurses, respiratory therapists, physicians. To remain inside with patients during the entire session.1
Multiplace chambers are standard equipment in major trauma centers, military hospitals, and research institutions. They represent the highest tier of hyperbaric medicine capability, enabling ICU-level care at pressures up to 6.0 ATA.
How Multiplace Chambers Work
Unlike monoplace chambers, which are pressurized with 100% oxygen, multiplace chambers are pressurized with compressed air. Patients breathe 100% oxygen through masks or hoods. The surrounding atmosphere remains air. Which significantly reduces fire risk despite high pressures. And allows the inside attendant to breathe without supplemental oxygen during normal operations.1
This design enables capabilities impossible in monoplace chambers: mechanical ventilation for intubated patients, IV drips, cardiac monitoring, defibrillation, and hands-on nursing care. A 2015 clinical review concluded that multiplace chambers are “better suited for HBOT of critically ill patients with failing vital functions and organ systems” precisely because of this inside-attendant capability.1
Multiplace vs Monoplace: Key Differences
| Feature | Multiplace | Monoplace |
|---|---|---|
| Capacity | 2–20+ patients plus attendant | 1 patient |
| Chamber atmosphere | Compressed air. O₂ via mask or hood | 100% O₂ |
| Max pressure | Typically 6.0 ATA | Typically 3.0 ATA |
| Inside attendant | Yes. Full ICU capability | No |
| Critically ill patients | Yes. Ventilators, IV access possible | Limited |
| Visual acuity changes | 18% reached 20/40 or worse | 32% reached 20/40 or worse |
| Cost | $500,000–$2,000,000+ | $50,000–$150,000 |
On visual acuity side effects, a 2016 study found that 32% of monoplace patients reached 20/40 vision or worse during treatment versus 18% in multiplace chambers. A statistically meaningful difference attributed to the continuous 100% oxygen atmosphere in monoplace units.2
The multiplace chamber is better suited for critically ill patients with failing vital functions and organ systems, because it permits ICU equipment to be used inside the chamber by accompanying staff.
Lind, Diving and Hyperbaric Medicine, 2015
Clinical Applications
Multiplace chambers handle the full range of UHMS-approved indications, with particular advantages for critical care situations: gas embolism, severe decompression sickness, necrotizing soft tissue infections, and cases where patients are too unstable to be left without monitoring. Military facilities use multiplace chambers for mass casualty decompression events. Treating multiple divers simultaneously.
For standard indications like wound healing, radiation injury, and chronic osteomyelitis, monoplace and multiplace chambers produce comparable outcomes. The choice depends on patient status and facility resources.
What Are the Side Effects and Risks?
Oxygen toxicity seizures are rare but possible. A study of over 1,000 treatment sessions found one oxygen toxicity seizure in the multiplace group versus zero in the monoplace group. A non-significant difference (p=0.31).3 The air atmosphere in multiplace chambers significantly reduces fire risk compared to monoplace designs pressurized with 100% oxygen.
Common adverse events remain similar across chamber types: temporary myopia (24.4%), ear barotrauma (14.9%), and confinement anxiety (11.5%) per UHMS survey data.4
Leading Manufacturers
Perry Baromedical (Riviera Beach, FL) and Sechrist Industries (Anaheim, CA) are the leading US manufacturers of multiplace chambers, both FDA-registered and ISO 13485 or ASME PVHO-1 certified. Perry’s multiplace systems can operate at up to 6.0 ATA with full ICU capability. Used and refurbished multiplace chambers are available through certified programs from both manufacturers.
For monoplace clinical chambers, see the hospital hyperbaric chamber guide. For an overview of hard shell chamber types including both configurations, see the hard hyperbaric chamber guide.
FAQs
Can family members accompany patients in a multiplace chamber?
In some facilities, yes. Attendants may be trained family members or clinical staff depending on protocol. All inside attendants follow specific safety procedures.
Is multiplace HBOT more effective than monoplace?
For most standard indications, outcomes are comparable. The advantage of multiplace chambers is in critical care situations where inside monitoring and intervention are needed during sessions.
What does a multiplace chamber cost?
New multiplace chambers cost $500,000 to $2,000,000 or more. Certified pre-owned units from Perry Baromedical and Sechrist are available at lower cost.
References
References
- Lind F. A pro/con review comparing mono- and multiplace hyperbaric chambers for critical care. Diving Hyperb Med. 2015. PMID: 25964041.
- Churchill S et al. Rates of visual acuity change in monoplace and multiplace chamber patients. Undersea Hyperb Med. 2016. PMID: 27416689.
- Bonnington S et al. Oxygen toxicity seizures during USN TT6 in monoplace chambers. Diving Hyperb Med. 2021. PMID: 34157732.
- Laspro M et al. HBOT regimens, treated conditions, and adverse effect profile: UHMS survey. Undersea Hyperb Med. 2024. PMID: 39821765.
Who Needs a Multiplace Chamber
Multiplace chambers are not interchangeable with monoplace units. Specific patient populations and clinical scenarios require multiplace capability:
- Critically ill patients: Intubated patients on mechanical ventilation, patients requiring IV medications during treatment, or patients who need continuous cardiac monitoring cannot be treated in monoplace chambers. The inside-attendant capability is essential, not optional, for these cases.
- Severe decompression sickness: US Navy Treatment Tables 6 and 6A, the standard protocols for serious decompression illness, can require pressures up to 6.0 ATA and treatment durations of 5+ hours. Only multiplace chambers achieve these pressures. Monoplace units are limited to 3.0 ATA.
- Pediatric patients: Children, particularly those under age 5, often require a parent or medical attendant inside the chamber during treatment. Multiplace chambers accommodate this naturally. Some centers treating children with conditions like traumatic brain injury prefer multiplace for this reason.
- Claustrophobic patients: The walk-in design of multiplace chambers (some seat 10 to 20 patients) eliminates the claustrophobia that causes 5 to 10% of monoplace patients to discontinue treatment. The larger space, ability to interact with staff and other patients, and ambient-air environment reduce anxiety substantially.
Multiplace Chamber Specifications
Clinical multiplace chambers share standard specifications across manufacturers:
- Pressure rating: Typically 6.0 ATA maximum (some rated to 8.0 ATA for research). Standard clinical treatments run at 2.0 to 2.8 ATA.
- Capacity: 2 to 20+ patient seats, plus attendant positions. The most common clinical configuration is 8 to 12 patient seats.
- Chamber atmosphere: Compressed air. Patients breathe 100% O2 via built-in breathing system (BIBS) masks or hoods. This design eliminates the fire risk of a pure-oxygen atmosphere at high pressure.
- Dimensions: Inner lock chambers typically 60 to 72 inches in diameter, 10 to 30+ feet in length depending on capacity. Larger installations require dedicated rooms with reinforced floors.
- Life support: Environmental control (temperature, humidity), CO2 scrubbing, fire suppression, communication systems, and medical gas outlets for oxygen, suction, and compressed air.
- Cost: $500,000 to $2,000,000+ for the chamber, plus $200,000 to $500,000 for installation, gas supply infrastructure, and facility modifications. Annual maintenance runs $50,000 to $100,000.
Perry Baromedical and Fink Engineering are the primary manufacturers of clinical multiplace chambers sold in the US. Both build to ASME PVHO-1 (Pressure Vessels for Human Occupancy) standards. Lead times for new installations typically run 6 to 12 months.
The Declining Multiplace Installed Base
An estimated 100 to 150 multiplace chambers remain in clinical operation in the US, down from higher numbers in prior decades. The decline is driven by economics: a multiplace chamber costs 10 to 40 times more than a monoplace unit, requires more staff per treatment session (inside attendant plus outside operator), and the reimbursement rate is the same regardless of chamber type.
This trend concerns hyperbaric medicine specialists. A 2024 UHMS survey found that facilities with only monoplace chambers cannot treat the sickest patients or handle the most serious diving emergencies. As multiplace chambers age out of service, some are not being replaced, potentially creating gaps in emergency hyperbaric capability. Patients needing multiplace-level care should verify that their nearest emergency HBOT facility still operates a multiplace system.
Medical Disclaimer
The content on BaricBoost.com is for informational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.
Author
Seph Fontane Pennock is the founder of BaricBoost.com and Regenerated.com, a clinic directory for regenerative medicine serving 10,000+ providers across the United States. He previously built and sold PositivePsychology.com, which grew to 19 million users and became the largest evidence-based positive psychology resource on the web. Seph brings direct experience as an HBOT patient, having completed protocols at clinics across three continents while navigating mold illness, systemic inflammation, and autoimmune conditions. His treatment journey includes hyperbaric oxygen therapy, peptide protocols, NAD+ therapy, and consultations with specialists from Dubai to Cape Town to Mexico. This combination of entrepreneurial track record and lived patient experience shapes everything published on BaricBoost.com. Every article is grounded in peer-reviewed research, informed by real clinical encounters, and written for patients making high-stakes treatment decisions. Seph's focus is on bringing transparency, scientific rigor, and practical guidance to the hyperbaric oxygen therapy space.
