The Christchurch Hyperbaric Medicine Unit treats a range of conditions ranging from decompression sickness and air embolism through to radiation injury and hypoxic problem wounds.
Hyperbaric oxygen therapy delivers oxygen under pressure to body tissues. The combination of pressure and high partial pressures of oxygen are the primary treatment for decompression sickness and arterial gas embolism. This form of therapy is a very useful adjunct to medical and surgical care in other conditions such as radiation injury and hypoxic problem wounds. The oxygen speeds up new microscopic blood vessel growth in certain types of wound and improves the ability of white blood cells to kill germs.
We are located on the lower-ground floor, Parkside West, Christchurch Hospital, near the western lifts.
To provide high quality patient care based on a strong commitment to practice, education, research innovation and collaboration within the Hyperbaric Medicine Unit.
The following conditions are treated at the Hyperbaric Medicine Unit:
The Hyperbaric Medicine Unit is staffed by a team of doctors, drawn from various departments (Emergency Medicine, General Practice and Anaesthesia) on a sessional basis, with Dr Greg van der Hulst as the Unit Clinical Director.
Technical Officers, in charge of the equipment and hyperbaric chamber.
Registered Nurses both part time and casual. Lorraine Angus is our current Charge Nurse.
Hyperbaric medicine began in Christchurch in 1973 with a trial of hyperbaric oxygen (HBOT) to enhance radiotherapy for patients with head and neck cancers. It was also used to treat acute problems such as decompression sickness, gas gangrene and carbon monoxide poisoning.
In the late 1970s, the local diving community raised the money for a dual-lock chamber which was donated to the North Canterbury Hospital Board. This operated at The Princess Margaret Hospital from October 1979 until 1994.
In late 1995, the chamber and associated plant were moved to Christchurch Hospital, allowing better access to core services such as radiology and intensive care. The unit provided emergency care and treated a few patients with problem wounds. In November 2000, the old chamber was replaced with a new, rectangular, walk-in chamber and permanent staff were appointed. This achieved the goal we set back in the early 1980s to establish the Christchurch unit as a major hyperbaric facility for New Zealand.
In January 2004, the compressors and high pressure air receivers were moved into a purpose-built plant room, as part of the Christchurch Women's Hospital redevelopment. We now have a double compartment 6-person recompression chamber for treatment with hyperbaric oxygen, with permanent medical, nursing and technical staff.
In November 2017 the chamber underwent a major upgrade. The panel was upgraded to a fully electronic system and the chamber interior was refurbished.
Read here for more information on diving accidents.
Referrals are accepted from New Zealand south of Taupo.
We accept patient referrals from any medical practitioner or nurse in independent practice (such as rural nurse practitioners).
For information about how to refer patients from the community, see HealthPathways.
For in-patient referrals, see HealthPathways
For referrers outside areas covered by HealthPathways, contact details area as follows:
Associate Professor (ret’d) F Michael Davis, formerly Medical Director, Hyperbaric Medicine Unit, Christchurch Hospital
(HBOT) is the intermittent administration of 100% oxygen at pressures greater than normal ambient pressure. There are several ways to provide this, all of which require a pressure vessel in which the patient(s) sit or lie for 2–3 hours daily for several weeks.
Six small, prospective randomised trials of HBOT for diabetic ulcers have been published.1–6 All show improved healing and, in two, a reduction in major amputation rate was reported (Table 1). Follow-up studies suggest these benefits are maintained in the medium to long term (3–5 years).8 However, a recent Cochrane review concluded there was a need for further large randomised studies because the trials (Table 1) had various flaws in design and/or reporting not meeting Cochrane criteria.9
HBOT is a moderately expensive treatment. In Christchurch, the estimated cost of a 30-treatment HBOT course is approximately $12,000 per patient. However, the cost-benefit studies from the UK and USA show an overall saving by combining HBOT with standard modalities of care in the management of diabetic ulcers, as well as improved outcomes.4,8 The UK study reported an overall saving of approximately NZ$8,000 per patient treated compared to non-HBOT care.4
Locally, we have too small a database yet to have a good idea of how well we are doing. However, of the first 50 lower limb ulcers of mixed aetiology (approx. half DM ulcers) referred to HMU, 18 (36%) were healed and 7 (14%) substantially improved on medium-term (approx. 3 month) follow-up (NNT for improvement = 2). There has been no major morbidity from HBOT in these patients. An on-going prospective cohort Australasian study of HBOT for problem wounds, both diabetic and non-diabetic, with over 400 cases shows a similar early post-HBOT healing rate, increasing to over 75% at one year, irrespective of the aetiology. Despite the Cochrane conclusions, we are firmly of the view, from our local clinical experience that HBOT, combined with multidisciplinary wound care improves healing in selected patients.
There are diverse actions of HBOT, including support of oxygen-dependent healing processes and, more importantly, cell-signalling effects that accelerate these processes for many hours beyond the HBOT exposure. The intermittent restoration of steep oxygen diffusion gradients in the peri-wound area stimulates fibroblast function in a dose-dependent manner.10,11 The cyclical pattern of hyperoxygenation/hypoxia leads to the release of local humoral mechanisms promoting wound healing. Recent work suggests a positive effect on nitric oxide metabolism in the diabetic wound. These changes result in an advancing field of neovasculogenesis. At the same time, oedema is reduced improving perfusion, and macrophage function is enhanced, particularly the ‘oxygen burst’ phase, in the hypoxic diabetic wound. HBOT is known to work synergistically with several antibiotics. Daily HBOT also corrects deficient neutrophil adhesion in Type II diabetes.
Any diabetic patient in whom a wound is not healing after a reasonable period of multidisciplinary wound care should be considered for HBOT. The international consensus is that an ulcer failing to respond after six weeks (or earlier, if the ulcer is limb-threatening) and for which no correctable large vessel disease is present should be referred for assessment for HBOT. Renal failure and concomitant major arterial disease carry a poorer prognosis for healing with HBOT just as they do with other interventions. Anecdotally, HBOT has been reported to be particularly useful in the neuropathic and Charcot foot.
The evidence in non-diabetic ulcers is more limited than for diabetic ulcers, but the same broad principles apply and HBOT has been shown to enhance healing in one small, prospective, randomised study.7
Problem wounds secondary to accidental trauma or medical misadventure in both diabetic and non-diabetic patients may be referred for assessment for HBOT under a prior approval ACC contract that has been in place nationally since March 2002. Many potential referrers are still unaware of this ACC-funded service.
Referrals to the Hyperbaric Medicine Unit at Christchurch Hospital may be made directly from primary care.
There are clinical HBOT facilities in Christchurch and Auckland, at the RNZN Medical Centre and at Quay Park Medical Centre. The only hyperbaric facility in New Zealand based in a civilian, tertiary-referral hospital is at Christchurch Hospital.
Table 1. Summary of randomised studies of hyperbaric oxygen therapy in diabetic and non-diabetic ulcers
|Patients||Outcome Measure||Results ||Statistics||Comments|
|Kalani et al1||38||Healed ulcer Amputation||
|follow up 3yr|
|Faglia et al2||68||Amputation||3/35||11/33||
|Doctor et al3||30||Amputation||2/15||7/15||<0.05||weekly HBOT only|
|Abidia et al4||18||
Healed ulcer at 1yr
Wound area decrease
|saving approx $8000per patient|
|Hammarlund & Sundberg7||16||Wound area decrease at 6 weeks||35.7%||2.7%||0.001||Diabetic and non-diabetic ulcers|
|Lee et al5 (abstract only)||32||
Wound healing time
|HBOT group had severer wounds; 2yr follow up|
|Londahl et al 6||94||Healed ulcer at 1yr||30/49||12/45||0.009||double blind|
|||Amputation: BKA or AKA |||||||
The Christchurch Hyperbaric Medicine Unit provides a 24 hour acute service for NZ south of Taupo, on request from emergency departments, ambulance and general practice.
For medical assistance contact:
Diver Emergency Service: 0800 4DES 111
Before diving, take a few minutes to review the safety training learned during SCUBA training courses.
Predisposition to Decompression Illness (DCI)
Planning a dive
Hyperbaric oxygen therapy is the administration of oxygen at a higher than normal atmospheric pressure, that is used to treat a limited but diverse range of illnesses. It is the primary treatment for disorders such as decompression illness, arterial gas embolism and carbon-monoxide poisoning.
It is also an effective adjunct in a combined program involving dressing changes, surgery and antibiotics for the enhancement of healing in non-healing 'problem' wounds.
Hyperbaric oxygen therapy is the medical use of 100% oxygen at increased pressure. It works in a variety of ways in the body. This increased pressure provides more oxygen to the body than is possible under normal conditions. Most treatments are between two and three atmospheres of pressure, and the pressure change closely approximates scuba diving.
This increase of pressure drives more oxygen into body tissues and wounds that are lacking adequate levels of oxygen (called hypoxia) speeding wound healing and helping the return of normal tissue functions.
The length and frequency of treatments is worked out for each person and the condition. Hyperbaric oxygen may be an important part of total care, including wound care, surgery and medication as indicated. For most patients, treatments are daily - Monday through Friday - and treatments may last 2 - 2 1/2 hours. Some emergency conditions will require only one or two treatments. In most cases of wound healing support, the effects are gradual, and 20 to 50 treatments may be required.
While in the chamber, treatments are managed by either a Registered Nurse or Diving Medical Technician with specialised training in hyperbaric medicine. An attendant is always in the chamber throughout treatment. The treatment is managed outside the chamber by a technician trained in pressure chamber operations. Medical care is rapidly available during treatments.
Everyone feels fullness in their ears as their eardrums adjust to the change in the chamber pressure. This is very similar to the feeling experienced when in an airplane or elevator. Instruction will be given on how to 'clear' ears, or equalize the pressure before treatment. If anyone experiences pain in their ears, the treatment is paused briefly until they are better.
Once the treatment begins air hisses into the chamber and it gets warmer. This will return to normal once the treatment pressure is reached.
During the treatment patients breathe from a special oxygen circuit through either a close fitting face mask or a clear plastic head-hood.
The attendant is there to deal with any problems straight away.
Depending upon the reason for coming to the Hyperbaric Medicine Unit, treatment can provide one or more of the following benefits:
There are risks to HBOT, but most of them can be dramatically reduced with the proper management. The risks can be divided into two types, physical and safety risks.
Fire is a higher risk when the chamber is under pressure because of the increased level of oxygen in the hyperbaric chamber. All patients and staff remove all extra items that might be a hazard.
Items that cannot be taken into the chamber:
Patients will be asked to remove anything with oil in it, such as:
Staff will arrange clothing to wear during the treatment. An undershirt of 100% cotton may be worn, to reduce the risk of electrostatic sparking.
Clothing not allowed in the chamber includes:
If you have any questions or concerns, talk to your hyperbaric doctor or nurse.
Page last updated: 28 June 2022
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