HYPERBARIC OXYGEN FOR TREATMENT OF
STROKE AND TRAUMATIC BRAIN INJURIES
DAVID A. STEENBLOCK, BS, MS, DO
26381 Crown Valley Parkway, Suite 130
Mission Viejo, CA 92691
Fifty stable, chronic stroke and traumatic brain injury (TBI) patients (mean age 62, mean duration post stroke 29
months) were treated with a combination of hyperbaric oxygen, physical therapy and EEG biofeedback for two
months. Surveys given to patients or their family members showed that 96.7% of the patients improved one or more
of their lost or diminished functions. Pre- and post-treatment, physical therapy evaluations indicated that 100% of the
patients experienced improvements in one or more functions. These results suggest hyperbaric oxygen therapy
along with other modalities provide safe and efficient treatment of stroke or TBI related disabilities.
Health institutes have shown different efforts to improve the quality of daily life for stroke patients. However, the
general outcome is not a encouragement, especially for those of long term stroke or brain injury related disorders
(TBI) patients. Although stroke is a leading cause of death and disability, its post management was often marked by
feelings of hopelessness.
Hyperbaric oxygen therapy (HBO) uses oxygen under pressure and first clinical use of hyperbaric oxygen for
treatment of stroke and TBI patients was reported in 1965. Since then many studies have demonstrated its safety
and efficacy (1,2,16-20). It is expected that HBO will be a competitive therapy for this devastating neurological
The dominant theory of stroke and TBI for more than 100 years has been that the loss of function is largely related to
the death of brain cells due to the interruption of blood flow and the resulting lack of oxygen to a part of the brain.
This traditional concept of infarction is being challenged by a theory which has been slowly evolving over the past 25
years. This theory states that the death of brain cells occurs only when the flow of blood falls below a certain level
(approximately 8-10 ml/100 gr./min., while at slightly higher levels of blood flow the tissue remains alive but not able
to function. Thus in the acute stroke the affected central core of brain tissue dies while the more peripheral tissues
may remain alive for many years after the initial insult, depending on the amount of blood the brain tissue receives
Brain areas that are injured and are not receiving enough blood flow as a result of the stroke or trauma are now
referred to as the "ischemic penumbra". This is the area that surrounds the central core of infarcted (dead) tissue.
These "rim" tissues do not receive enough oxygen to function but do receive enough to stay alive. These brain cells
have been described as "sleeping beauties", "sleeping neurons" or "dormant" or "idling neurons". These neurons
are nonfunctional but anatomically intact and can be revived. ( 3), (8-10).
It is widely recognized that damaged blood vessels are thought to produce the ischemic penumbra in stroke or TBI.
In the acute phase of stroke or TBI, those damaged blood vessels lead to significant edema (swelling of the tissues
as a result of the damage). This swelling may take up to 9 to 12 months to resolve, and the swelling compresses brain
blood vessels, limits the flow of blood to the damaged tissues. As the swelling goes away, some of the blood vessels
will regain their original diameters and normal blood flow will resume (9). It was widely documented that the water
content of edematous tissue of the brain was decreased significantly by HBO. (12-14).
Another process is "neovascularization", also known as "angiogenesis". This is the process of forming new
capillaries that extend from the surrounding healthy brain tissue into the areas of the ischemic penumbra. The
outermost portions of the ischemic penumbra (those portions closest to normal brain tissue) are able to metabolize
but at a reduced rate than normal tissues, however, they are receiving more blood and oxygen than the centrally
located ischemic tissues. Adenosine, a metabolite of ATP, is released from ischemic "rim" tissues when cells
metabolism and repair. Adenosine is a vasodilator that stimulates new capillaries to grow into the ischemic penumbra
(neovascularization). Thus during the first year after a stroke or TBI, new blood vessels are stimulated to move into
the ischemic penumbra to re-supply it with a new blood supply. (9)
Unfortunately, the ischemic penumbral tissues closer to the infarct area usually are not receiving enough oxygen or
nutrients to generate adequate amounts of ATP - either from aerobic or anaerobic metabolism for neovascularization
to occur. Due to the lack of ATP formation, adenosine is not produced and the formation of new capillaries does not
occur. Thus the ischemic penumbra remains ischemic and static since the process of neovascularization is not able to
be completed. This often results in a substantial amount of brain tissue that remains ischemic and non-functioning in
the chronic stroke and TBI patients. This failure of natural healing processes is due ultimately to damaged blood
vessels and their inability to provide oxygen and nutrients to those portions of the brain that are damaged.(11)
Hyperbaric oxygen works to improve chronic stroke and TBI patients by regenerating, repairing and generating new
blood vessels to the injured parts of the brain. In the ischemic penumbra, the blood vessels are often constricted to
the point that red blood cells can not pass through them. This creates the situation where only plasma is able to pass
slowly to part or most of the ischemic area. Since plasma has nutrients, the tissues of the ischemic penumbra are able
to remain alive by using anaerobic glycolysis (metabolism without oxygen) also known as fermentation.. Anaerobic
glycolysis only produces 2 moles of ATP per mole of glucose metabolized instead of the 36 moles of ATP formed
when oxygen is present. Thus the tissues suffer from a chronic shortage of ATP and its subsequent metabolite-
adenosine. Hyperbaric oxygen forces oxygen into the plasma to such a degree that as the plasma passes into the
ischemic penumbra, the ischemic tissue begins to receive enough oxygen for aerobic glycolysis (metabolism that
uses oxygen) to occur once more. This creates a surge of ATP production in the ischemic tissue which continues to
be produced as long as the patient is within the hyperbaric oxygen chamber. When the patient is taken out of the
chamber, blood and tissue levels of oxygen fall back to pre-treatment levels within 4 hours. As the tissue oxygen
level falls, the newly generated ATP is used by the ischemic tissues and adenosine is released into the surrounding
tissues in an effort by the tissues to continue to receive the oxygen that it just had been receiving. As a part of this
survival mechanism, adenosine and other chemical mediators are released into the surrounding tissues stimulating
angiogenesis. Done daily over time, the HBO stimulates new blood vessels to grow into the ischemic tissues
returning them back to normal in terms of their oxygen supply. Recovery of function is associated with recovery of
local perfusion and metabolism. (11)
Once the ischemic penumbral tissues are no longer suffering from a lack of oxygen, they are able to begin to repair
their injured neurons, glial cells and extracellular matrix. These tissues now have to try to repair their own cell
bodies, dendrites, axons and synapses but also have to grow out and extend to the many lost connections that
occurred with the stroke.
Treatment of acute and chronic focal cerebral ischemia with hyperbaric oxygen has been reported both in animal and
in humans. The results of the clinical research have suggested a promising role for the use of HBO. (2, 16-20). In
this study, we showed that HBO is quite effucient when used as a part of combined therapy and patients did benefit
from this therapy.
50 patients ( male 21 and female 29) voluntarily enrolled in this study. Patient's ages ranged from 31-89 years with a
mean age of 61.8 years. The duration from onset of stroke to entry into our rehabilitation program varied from 1
month to 10 years. The average duration since stroke onset was 28 months. 3 of the patients suffered chronic stroke
more than 8 years.
Table 1 : Patient's Pre-Treatment Condition
9 brain hemorrhage
4 embolic infarction
3 stroke after brain surgery
1 a car accident
33 ischemic infarction (thrombosis)
1. HBO Treatment: Patients received hyperbaric oxygen therapy (HBO) at a pressure of 1.5. to 2.0 atmospheres
absolute (ATA) in a sealed single person chamber. Oxygen (100% medical grade) was inhaled through a plastic face
The therapy was carried out for 90 minutes per day and 6 times per week in most patients. A few patients received
HBO treatment twice a day. The average number of HBO treatments completed was 55.
Hyperbaric oxygen therapy feels much like going for a ride in a modern day jet - the chamber even looks like the
cockpit of a jet fighter plane! As patients start their treatment they are sitting upright at a comfortable angle inside of
this cockpit like chamber. Patients have an oxygen mask over their mouth and nose, the door is shut and they feel a
slight movement of air as the chamber begins to be filled with more air. As the air enters the chamber you may notice
a slight discomfort in one or both ears just like they have experienced while flying in the large commercial jets.
Patients may choose to swallow, chew gum or hold their nose and blow outward to help equalize the pressure in their
2. Physical Therapy Treatment: Physical therapy procedures included various physical activities and modalities as
needed. The modalities used were electrical stimulation, hot or cold packs, ultrasound, short wave diathermy and
paraffin bath therapy. Each patient's condition was evaluated to determine the appropriate modality, dosage,
placement and methods of application.
Physical therapy techniques were provided and adjusted as the patient's condition warranted. These included
strengthening, range of motion, endurance exercise, neurodevelopmental technique, joint mobilization, kinetic
activities, myofascial release and detailed gait or orthotic training.
Initial evaluation assessed range of motion, strength grades, bed mobility, transfer status, balance, neurological
findings, posture and ambulatory status. Periodic re-evaluations were performed to assess each patient's progress,
and treatment plans were changed as needed. Upon discharge, a discharge evaluation was performed to assess
progress and determine patient's long term therapy program.
The number of therapies varied from 13 to 85 treatments with a mean of 40. Patients came to physical therapy 5
times per week.
3. Bio-Feedback Treatment: Patients came to biofeedback therapy 5 times per week and recieved a minimum of 21 (
mean 35) one-half hour daily sessions of EEG biofeedback. Sessions consisted of inhibiting and rewarding varous
selected EEG frequencies through audio and visual displays to encourage flexability in brain activity. Each sessioin's
threshold level were automatically calibrated by the instrument ( American Biotech Capscan 80) and a frequency
spectral display summerized EEG amplitudes over 0 to 32 Hertz.
C. Treatment Evaluation.
The effects of treatment were evaluated by a patient's questionnaire and a licensed physical therapist's evaluation
both given at the beginning of the program and again at the end.
In the patient questionnaire, 16 different functions ranging from motor ability and mental situations were analyzed.
Patient's functions were self graded as followings:
- : negative change
0: no improvement at all.
Slight improvement: 1-10 % of the function improved.
Mild improvement: 10- 25% of the function improved.
Moderate improvement: 20-50% of the function improved.
Significant improvement: 50 -75% of the function improved.
Back to normal: 100% of the function improved.
In the physical therapist's evaluation, 33 different functions ranging from motor ability to cognitive functioning were
analyzed. For statistical purposes we assigned the therapist's evaluation of each parameter as either being no
improvement or improvement.
Range of movement: NA stands for "not available" because the patient's function was within normal limits before the
treatment. " No improvement" means the increased range of movement is less than 10 degrees. "Improvement"
stands for when the range of movement increased 10 degrees or more. No matter how much more than 10 degrees of
increased range of motion occurred, all positive results were grouped simply as "improvement".
Extremities strength evaluation: Grading was on a 0-5 degree scale with 0 indicating no strength and 5 indicating
normal as compared to the non-involved extremity. NA stands for "not available" because the patient's function of
that extremity was normal before the treatment. No improvement means the increased strength is less than one
degree, such as from 3- to 3+ was considered as no improvement. Improvement stands for the strength increased at
least one degree, such as from 2 to 3. No matter how much more than one degree of improvement occurred in a
particular patient, all of these patients with positive results were grouped simply as "improvement"
Other functions such as bed mobility, transfer ( supine to sit, sit to stand, bed to chair) balance ( sitting, standing,
ambulatory) were graded as:
#3, good with care;
#4, with minimal assistance;
#5, with maximal assistance;
Improvement was defined to occur when the patient's functional evaluation score decreased by at least 1 (#6 being
unable to perform the task and #1 being able to do the task independently)
A: Patient Questionnaire:
Patient questionnaires were collected prior to and after the series of treatments. Patients' general comments for this
program are presented in Table 2.
Consider this program poor 00.0%
No improvement (received 22 HBO treatments only) 03.3%
Consider this program good 30.0%
Consider this program excellent 46.7%
Consider this program "stupendous" 20.0%
Total Patient improvement in at least one of the functions is 96.7%
Only insignificant problems were encountered with the combination of therapies for treating chronic stroke patients.
The summary of the patients' self evaluation is in table 3.
Table 3: Improvement level as evaluated by patients/caretakers.
Function %No %Slight %Mild %Mod. %Significant %Total Patient Improvement
Arm's motor ability 34.29 0.00 34.29 14.29 17.14 65.72
Arm's Sensitivities 43.48 26.09 4.35 13.04 13.04 56.52
Finger's movement 32.26 32.26 0.00 16.13 19.35 67.74
Leg's motor ability 13.16 13.16 34.21 21.05 18.42 86.84
Walking's manner 13.51 0.00 24.32 35.14 27.03 86.49
Sit down ability 30.00 0.00 13.33 33.33 23.33 70.00
Stand up 33.33 0.00 10.00 40.00 16.67 66.67
Foot 53.57 21.43 0.00 14.29 10.71 46.43
Speech 26.09 4.35 30.43 21.74 17.39 73.91
Memory 20.83 0.00 29.17 25.00 25.00 79.17
Thinking 16.67 0.00 20.83 37.50 25.00 83.33
Understanding 13.64 0.00 27.27 31.82 27.27 86.36
Urine control 31.35 0.00 21.05 21.05 26.32 68.42
Bowel Control 17.65 17.65 11.76 11.76 41.18 82.35
Vision 47.37 0.00 15.79 10.53 26.32 52.63
Hearing 46.67 0.00 13.33 6.67 33.33 53.33