scubadoc Ten Foot Stop

Hyperbaric Healing Institute
http://www.hhi-kc.com/sideeffects.htm

Side Effects
As with any treatment, side effects are possible. However, with hyperbaric oxygen therapy they are minimal. The most common is barotrauma to the ears and sinuses caused by pressure changes.

Patients are taught autoinflationary techniques to promote adequate clearing of the ears during treatment. Decongestants may be helpful. This problem is temporary and resolves when HBO treatment is completed.

If the patient has ear pain or is unable to clear his or her ears, the insertion of myringotomy tubes may be necessary before the treatment continues.

Taken from a 10-year study of 1,505 patients who received 52,758 2-hour HBO treatments at 2.4 ata once or twice daily (The maximum treatment protocol used for problem wounds around the world).

Inability to equalize middle ear pressure 0.37%
Paranasal sinus blocks 0.09%
Confinement anxiety 0.05%
Oxygen convulsions 0.009% (all ceased after removing hood/masks)
Pulmonary oxygen toxicity 0.00%
Permanent ocular refractive changes 0.00%

Other side effects are more rare.

Oxygen toxicity can cause CNS and pulmonary effects. Seizures occur rarely during treatment and are self limiting.
Seizures will cease when the patient is removed from breathing the pure oxygen.
Factors such as history of seizures, high temperature, acidosis and low blood sugar are taken into account before treatment is begun.
Pulmonary oxygen toxicity may occur in patients who require supplemental oxygen between treatments. This is very rarely seen with the limited number of treatments currently used.
Some patients may suffer claustrophobia. This is managed by maintaining communication, use of relaxation techniques and mild sedation, if necessary. Incidents of claustrophobia, however, are decreased by HHI’s large diameter multiplace chamber.
Rarely, patients develop temporary changes in eyesight; these are minor and occur only in those individuals who have large numbers of treatments. Vision usually returns to normal within eight weeks following the end of treatments.
Patients with cataracts may experience accelerated maturation of the cataract, but the treatments do not cause cataract formation.

Contraindications
Anyone with any of the following conditions may not be a suitable candidate for HBOT:

1. Asthma - Small airway hyper-reactivity may result in air trapping and pulmonary barotrauma on ascent. A decision to treat such patients should not be undertaken lightly, particularly in light of evidence that the administration of some bronchodilators may increase the incidence of cerebral arterial gas embolism through pulmonary vasodilation.

2. Congenital spherocytosis - Such patients have fragile red cells and treatment may result in massive haemolysis

3. Cisplatinum - There is some evidence that this drug retards wound healing when combined with HBO.

4. Disulphiram (Antabuse) - There is evidence to suggest that this drug blocks the production of suproxide dismutase and this may severely effect the body’s defenses against oxygen free radicals. Experimental evidence suggest that a single exposure to HBO is safe but that subsequent treatments may be unwise.

5. Doxorubicin - (Adriamycin). This chemotherapeutic agent becomes increasingly toxic under pressure and animal studies suggest at least a one week break between last dose and first treatment in the chamber.

6. Emphysema with CO2 retention - Caution should be exercised in giving high pressures + concentrations of oxygen to patients who may be existing on the hypoxic drive to ventilation. Such patients may become apnoeic in the chamber and require IPPV. In addition, gas trapping and subsequent lung rupture are associated with bullous disease.

7. High Fevers - High fevers (>38.5degC) tend to lower the seizure threshold due to O2 toxicity and may result in delaying of relatively routine therapy. If patients are to be treated then attempt should be made to lower their core temperature with antipyretics and physical measures

8. History of middle ear surgery or disorders - These patients may be unable to clear their ears, or risk further injury with vigorous attempts to do so. An ENT consult for possible placement of grommets is usually wise

9. History of seizures - HBO therapy may lower the seizure threshold and some workers advocate increasing the baseline medication for such patients

10. Optic Neuritis - There have been reports in patients with a history of optic neuritis of failing sight and even blindness after HBO therapy. This complaint would seem to be extremely rare but of tragic consequence.

11. Pneumothorax - A pocket of trapped gas in the pleura will decrease in volume on compression and re-expand on surfacing during a cycle of HBO therapy. During oxygen breathing at depth nitrogen will be absorbed from the space and replaced with oxygen. These fluxes of gases and absolute changes in volume may result in further lung damage and or arterial gas embolization. If there is a communication between lung and pneumothorax with a tension component, then a potentially dangerous situation exists as the patient is brought to the surface. As Boyle’s Law predicts, a 1.8 litre pneumothorax at 20 msw is potentially a 6 litre pneumothorax at sea level - certainly a life threatening situation. For this reason it is mandatory to place a chest tube to relieve a pneumothorax before contemplating HBO therapy. Particular care must be taken with patients who give a history of chest trauma or thoracic surgery.

12. Pregnancy - The fears that either retrolental fibroplasia or closure of the ductuc arteriosus may result in the fetus whose mother undergoes HBO appear to be groundless from considerable Russian experience. However, HHI continues to exercise caution in limiting treatment of pregnant women to emergency situations.

13. Upper Respiratory Tract Infections - These are relative contra-indications due to the difficulty such patients may have in clearing their ears and sinuses. Elective treatment may be best postponed for a few days in such cases.

14. Viral Infections - Many workers in the past have expressed concern that viral infections may be considerably worsened after HBO. There have been no studies to give convincing evidence of this and no reported activation of herpetic lesions associated with HBO.

References to Risks of HBOT on scubadoc Diving Medicine Online

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We have placed the following summary of guidelines for recreational diving with diabetes recommended by UHMS/DAN workshop on our web site at http://www.scuba-doc.com/endmet.html#Diabetes_and_Diving.
(Proceedings of the UHMS/DAN 2005 June 19 Workshop. Durham, NC:Divers Alert Network; 2005.)

Table 1: Guidelines for Recreational Diving with Diabetes - Summary Form 1
Selection and Surveillance
• Age ≥18 years (16 years if in special training program)
• Delay diving after start/change in medication
- 3 months with oral hypoglycemic agents (OHA)
- 1 year after initiation of insulin therapy
• No episodes of hypoglycemia or hyperglycemia requiring intervention from a third party for at
least one year
• No history of hypoglycemia unawareness
• HbA1c ≤9% no more than one month prior to initial assessment and at each annual review
- values >9% indicate the need for further evaluation and possible modification of therapy
• No significant secondary complications from diabetes
• Physician/Diabetologist should carry out annual review and determine that diver has good
understanding of disease and effect of exercise
- in consultation with an expert in diving medicine, as required
• Evaluation for silent ischemia for candidates >40 years of age
- after initial evaluation, periodic surveillance for silent ischemia can be in accordance with
accepted local/national guidelines for the evaluation of diabetics
• Candidate documents intent to follow protocol for divers with diabetes and to cease diving and
seek medical review for any adverse events during diving possibly related to diabetes
Scope of Diving
• Diving should be planned to avoid
- depths >100 fsw (30 msw)
- durations >60 minutes
- compulsory decompression stops
- overhead environments (e.g., cave, wreck penetration)
- situations that may exacerbate hypoglycemia (e.g., prolonged cold and arduous dives)
• Dive buddy/leader informed of diver’s condition and steps to follow in case of problem
• Dive buddy should not have diabetes
Glucose Management on the Day of Diving
• General self-assessment of fitness to dive
• Blood glucose (BG) ≥150 mg·dL -1 (8.3 mmol·L -1 ), stable or rising, before entering the water
- complete a minimum of three pre-dive BG tests to evaluate trends
 60 minutes, 30 minutes and immediately prior to diving
- alterations in dosage of OHA or insulin on evening prior or day of diving may help
• Delay dive if BG
- 300 mg·dL -1 (16.7 mmol·L -1 )
• Rescue medications
- carry readily accessible oral glucose during all dives
- have parenteral glucagon available at the surface
• If hypoglycemia noticed underwater, the diver should surface (with buddy), establish positive
buoyancy, ingest glucose and leave the water
• Check blood sugar frequently for 12-15 hours after diving
• Ensure adequate hydration on days of diving
• Log all dives (include BG test results and all information pertinent to diabetes management) 1 For full text see: Pollock NW, Uguccioni DM, Dear GdeL, eds. Diabetes and recreational diving:guidelines for the future. Proceedings of the UHMS/DAN 2005 June 19 Workshop. Durham, NC: Divers Alert Network; 2005.

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In an article in the journal Chest titled “Decline of FEV1 in Scuba Divers”, a study is reported by Tetzlaff et al that puts to rest the supposition that prolonged diving causes lung problems.
(Kay Tetzlaff, MD; Jens Theysohn, MD; Caroline Stahl; Sabine Schlegel, PhD; Andreas Koch, MD and Claus M. Muth, MD)
Abstract of the article
Correspondence to: Kay Tetzlaff, MD, Medical Clinic and Polyclinic, Department of Sports Medicine, University of Tuebingen Silcherstrasse 5, 72076 Tübingen, Germany; e-mail: Kay.Tetzlaff@med.uni-tuebingen.de

Study objectives: Obstructive changes in lung function have been reported with cumulative scuba diving exposure. The aim of this study was to investigate the decline in FEV1 in scuba divers over time.

Design: Prospective controlled cohort study.

Setting: German Naval Medical Institute.

Patients: Four hundred sixty-eight healthy, male, military scuba divers and 122 submariners (control subjects) were entered.

Measurements and results: Pulmonary function tests were performed in all subjects on at least three occasions with a minimum interval of 1 year between first and last measurement. The decline in FEV1 was investigated fitting a general linear model to FEV1 across time with a factorial main-effects model for slopes and intercepts with respect to the factors group, smoking status, and baseline FEV1. Mean baseline age of all subjects was 32 years (SD, 9.1), and mean body mass index was 24.7 kg/m2 (SD, 2.4). Subjects were followed up for 5 years (range, 1 to 9 years) on average. Baseline FEV1 exceeded the predicted values in both divers and nondiving control subjects. There was no significant difference in the decline of FEV1 between divers and control subjects. Over time, FEV1 declined more rapidly in smokers than in nonsmokers (p = 0.0064) and declined more rapidly also in subjects with a baseline FEV1 above average compared to subjects below average (p Conclusions: The data indicate that scuba diving is not associated with an accelerated decline in FEV1. Combined exposure to diving and smoking contributes to the fall of FEV1; therefore, smoking cessation is advised for divers.

Full text of the article.

Thanks to Dr. Howard Hommler who sent us the article.

Related links on scubadoc Diving Medicine Online
‘Smoking and Diving’

Cigarette smoking and decompression illness severity: a retrospective study in
recreational divers.
http://snipurl.com/3ldd

Should Divers Smoke and vice versa

http://snipurl.com/3ldf

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In response to a question about diving and obesity - here is an answer giving the ideal body weight for diving:

Edmonds, in the book, Diving and Subaquatic Medicine, states that weight should be less than 20 % above the average ideal weight for age, height and build. Obesity is undesirable because it increases the risk of decompression illness, there being an increase in nitrogen absorption of 4.5 times in fat. Sport diving is more lenient than commercial in this regard in that the bottom times can be reduced according to the percentage that the candidate’s weight exceeds that expected for height and build.

Body mass index (BMI) is a method for determining the percentage of fat. It is determined by weight in Kg divided by height in meters squared.

In some areas of the world where medical fitness is more stringently regulated than the US, a high BMI (body mass index) would deter one from diving. Complicating conditions of adiposity include diabetes mellitus, dyslipidemia or hypertension and their associations with coronary artery disease. The BMI is important to divers due to the fact that people with high BMI are more prone to coronary artery disease and an untoward coronary event while diving. A BMI above 30 kg/m2 is thought to be excessively risky for diving. Of course, measured %BF can sometimes show that the diver is quite large and muscular and this needs to be taken into consideration. Figure your BMI by going to this web site:
http://www.nhlbisupport.com/bmi/bmicalc.htm

In one of our newsletters, reference was made to the approximate number of calories burned while scuba diving. The figures quoted (393 kcal for a person weighing 130 pounds, 413 kcal for 155 pounds, 604 kcal for 190 pounds) were all estimates but seemed inordinately high to some people who felt that scuba diving was essentially a sedate activity in a weightless milieu.

In researching a valid answer to this question we came up with some data that hopefully explains the burning of oxygen - and thus calories (kcal). There are quite a few variables in the equation, such as water temperature, level of fitness of the individual, size and body configuration of the diver, current, surge and buoyancy. Swimming energy is also proportional to the square of the velocity and workloads for higher use are tolerated by only the very fit.

Maximum burning of oxygen in the very fit is 40ml/kg/minute (VO2). Resting VO2 is 3.5ml/kg/min. or 1.5-2 kcal (1 MET). All things being equal, the act of scuba diving at a speed of 1 knot burns about 25 ml/kg/min of O2 (about 60% of maximum), the diver moving about 70 feet per minute. (Bove, ’Diving Medicine’, 1997).

A resting value of 3.5ml/kg/minute interpolated to 25 ml/kg/min is 8 kcals/min. A diver swimming for one hour at this rate would burn 480 calories, depending upon any or all of the variables noted above. See also: Nutrition and Diving

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Performance of Infusion Pumps in Hyperbaric Conditions

Abstract [Full Text]

Background: Many hyperbaric facilities use infusion pumps inside the chamber. It is therefore important to ensure that this equipment will perform accurately during hyperbaric conditions. The authors tested the function and accuracy of the Imed 965 and Infutec 520 volumetric infusion pumps, the Easy-pump MZ-257 peristaltic infusion pump, and the Graseby 3100 syringe pump.

Methods: The authors calculated the deviations of infused volumes at low and high rates (12-18 and 60-100 ml/h) on three different hyperbaric protocols (up to 2.5, 2.8, and 6 atmospheres absolute [ATA]), resembling a standard hyperbaric oxygen treatment and US Navy treatment tables used for decompression illness and for arterial gas embolism. Two examples of each pump model were examined in every experiment.

Results: The Easy-pump MZ-257 failed to function completely beyond a chamber pressure of 1.4 ATA, making it unsuitable for use inside the hyperbaric chamber. The Graseby 3100 failed to respond to all keyboard functions at 2.5-2.8 ATA, making it unsuitable for use in most hyperbaric treatments. The Imed 965 performed within an acceptable volume deviation (≤10%) during most hyperbaric conditions. During the compression phase of the profiles used, and for the low infusion rates only, exceptional volume deviations of 20-40% were monitored. The Infutec 520 demonstrated an acceptable deviation (within 10%) throughout all the hyperbaric profiles used, unaffected by changes in ambient pressure or infusion rate.

Conclusions: Commercially available infusion pumps operating during hyperbaric conditions demonstrate substantial variations in performance and accuracy. It is therefore important that the hyperbaric facility staff make a careful examination of such instruments to anticipate possible deviations in the accuracy of the equipment during use.

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