Carl Rand: Pacific Grove Hyperbaric Chamber

  • Carl Rand

By: Carl Rand

(Editor’s Note: Thanks to Carl for presenting such a good and informative program about the Chamber, and for writing this excellent report. We also thank the folks who operate the Chamber for the benefit of all the divers and other users on the Central California Coast. Our club donated $691 to PGHC this past year, so we recognize that it’s an important asset!)

At our May general meeting, Carl Rand presented a program on the Pacific Grove Hyperbaric Chamber (PGHC) and how hyperbaric oxygen therapy is used in treating diving injuries as well as carbon monoxide poisoning cases.

Carl Rand presenting at the May general meeting.

Carl Rand presenting at the May general meeting.

Carl has been diving since 1974 and received a degree in marine biology from Occidental College. After working a few years as a marine research biologist and science teacher he pursued a career in business but remained active in marine science through his scuba diving and sailing activities. He joined the crew of the PGHC in 2013 and has been active as a recorder and operator on multiple DCS and carbon monoxide (CO) treatment cases.

Carl’s program covered a brief history of the hyperbaric chamber, an explanation of the criteria for the different types of cases that are treated, the benefits of hyperbaric oxygen therapy, protocols for receiving and treating patients, recent trends in DCS cases, how divers can respond in emergency situations where recompression might be necessary, and safe diving practices we can all follow in order to minimize decompression sickness (DCS), arterial gas embolism (AGE) or carbon monoxide (CO) poisoning.

The PGHC began operations with a monoplace chamber in 1966. In those days, DCS cases were treated by recompressing the diver to 165 FSW on air, and the cycle could take up to 12 hours. AGE cases could run as long as 36 hours. In 1984, PGHC upgraded their facility to a much larger multiplace chamber. This is the chamber in use today and has two sections: larger side for treatment, and a smaller side which functions as a lock – allowing independent diving and ascent for transport of food, supplies, medications, and personnel if necessary. In 2014 the chamber was renovated and recertified. It continues to operate as a freestanding facility, housed in the Pacific Grove fire station. We are staffed by an all volunteer crew, including the physicians who are onsite during the treatment of any case.

Original single-person chamber and newer multiple-person chamber.

Original single-person chamber and newer multiple-person chamber.

Due to the unique circumstances of any medical treatment facility, there are certain protocols that determine whether cases can be treated. At PGHC we are established to treat emergencies, not to provide routine medical care (e.g. wounds). Although we are on call 24 x 7, we are not staffed to accept walk in patients; and require medical referral which is typically from the local Community Hospital of the Monterey Peninsula (CHOMP) or Divers Alert Network. We are able to treat patients within 72 hours of symptom onset; however, we do not provide retreatment or handle non-emergency cases.

The three types of cases we typically treat are decompression sickness, arterial gas embolism, and carbon monoxide poisoning. Decompression illness, comprising both decompression sickness and AGE, primarily involve scuba divers; however, we have treated military pilots who have experienced decompression symptoms due to cockpit depressurization. Patients requiring carbon monoxide poisoning treatment are typically from the general population. These cases often occur in the wintertime and are the result of faulty, or poorly maintained, heating systems.

When oxygen is provided for treatment at pressures greater than one atmosphere, it is considered a drug and can only be administered by prescription. Prior to any hyperbaric treatment, medical evaluation is extremely important because certain conditions, such as pneumothorax, are contraindications and would preclude hyperbaric treatment, even in a diver who has DCS. So as a diver helping to treat someone suspected of DCI be sure to engage EMS and have the patient evaluated at a hospital where more advanced diagnostics such as x-rays or CT scans can be performed. If the physician at the emergency department believes hyperbaric treatment is warranted, the patient will be transported to the chamber.

At the chamber we will perform a secondary evaluation of the patient including a rapid field neurological examination. The patient receives their diagnosis from the physician and is oriented to the treatment process. Since we are a medical facility, we need to provide all the appropriate informed consent and other medical and insurance paperwork, such as HIPAA guidelines notification, that would be provided in any outpatient facility.

View inside chamber.

View inside chamber.

A crew of the least five individuals is required to run a case. There is always a medically trained tender within the chamber with the patient, and an operator, recorder, and supervisor working the case from the outside. The role of the recorder is to take detailed notes on all activities and medical procedures that happen as part of the treatment. The operator manipulates the controls and ensures the safe operation of the chamber. The supervisor oversees all activities and coordinates any specific needs between tender inside the chamber and the operators and physician outside. During the entire operation, a physician is present and responsible for all medical treatments and decisions. Upon completion of the hyperbaric treatment cycle, the patient is returned to the emergency department for final discharge.

For a decompression sickness treatment we typically begin by taking the patient to a depth of 60 FSW and providing three alternating oxygen – air breathing cycles which can be extended if symptoms are not relieved. After the first phase of treatment at 60 FSW the patient is brought to 30 FSW for an additional cycle of treatments. Ascent rates are extremely slow and controlled at 1 foot per minute. While in the chamber, the patient receives their oxygen through a special mask system referred to as the built in breathing system or BIBS. This allows the patient to receive 100% oxygen during their oxygen treatment cycle while the exhaled oxygen rich air is vented outside the chamber, thus keeping ambient chamber oxygen levels at safe concentrations.

The slides of the presentation have been provided to the club for those who are interested.

Editor Note: PGHC is a 501 (c )(3) non-profit. You can get more information and donate at


During the presentation, several questions were raised and we are providing answers to them here:

  1. What is the cost of these treatments? A typical DCS case costs approximately $2,000 for facility and material charges. There is no charge for professional services as all the crew members, including the physicians, are volunteers. PGHC will bill the patient’s insurance company directly or Divers Alert Network if the diver is covered by a DAN accident insurance policy. We highly recommend DAN insurance for all divers.
  2. Why would a military pilot get DCS? The aviation DCS cases that we have treated involve situations in which the aircraft cockpit becomes depressurized. This is equivalent to a scuba diver experiencing a rapid ascent. So pilots are susceptible to the same conditions as scuba divers and are treated in similar fashion.
  3. Does the military have its own recompression facilities? Do they make contributions to the PGHC? Yes, they do have facilities and the PGHC acts as a secondary facility for some military operations. We have been on stand-by for Navy diving operations in the Monterey Bay area, and have treated some Navy pilots for DCS. The military does not make a direct financial contribution to the chamber; however, they do provide their own physician (flight surgeon) when we treat a patient for them.
  4. How do you treat divers with carbon monoxide poisoning? CO poisoning in divers is treated in the same fashion as it would be for a non-diving patient. Our CO treatment tables take the patient to three atmospheres (66 FSW) for the first phase and then two atmospheres (33 FSW) for the second. This is slightly deeper than the treatment depths for DCS, which are typically 60 FSW for the first phase, followed by 30 FSW for the second. The ascent rates are faster for CO treatments (10 ft./min.) compared to DCS treatments (1 ft./min.).
  5. What was the reason for the spike in DCS cases in 1989? In the graph of DCS trends, you noticed that there was an increase in cases during this one year. We don’t have a specific analysis explaining why the DCS cases spiked at that time. Our records from that time are paper-based, and we are going to review the data to see if there are any discernable patterns that explain the DCS case spike. We will report any information we find back to the dive club.
  6. Is there a tender in the chamber with the patient? Yes, for every treatment a medically trained crew member (tender) is inside the chamber with the patient being treated. Working on the outside are the recorder, operator and supervisor, who oversees the entire operation. A physician with hyperbaric specialty training is present at the chamber throughout every case treatment.