Theoretical tissue compartment inert gas pressures during a deep dive with and without deep decompression stops: a case analysis.

BACKGROUND: Deep decompression stops are increasingly common in recreational technical diving. Concerns exist that they shift decompression stress back into slower tissues. A diver recorded an exceptional exposure dive, with deeps stops, on a commercially available dive computer. MATERIAL AND METHODS: Using the R package SCUBA tissue inert gas pressures in 17 Bühlmann (ZH-L16A) compartments were estimated from the dive computer recorded profile. The RGBM dive plan generated by the diver's software was similarly interrogated, as was a third profile with reduced deep stops generated using the VPM-B/E model. RESULTS: In this dive the combination of 5 gas switches appeared to ameliorate the effect of deep stops from 76 m depth. CONCLUSIONS: A higher-than-anticipated inert gas content in a decompression mixture, coupled with climbing 200 stairs post-decompression, appear possible risk factors for decompression sickness. Nonetheless, the physiological effect of deep decompression stops during exceptional exposure, even when diving with gas switches, remains urgently to be determined to improve safe decompression following exceptional exposures. Until algorithms utilising deep decompression stops are validated with human data, dive profiles incorporating deep decompression stops should be considered experimental.

Hyperbaric oxygen is effective in early stage of healing of experimental brain abscess in rats.

OBJECTIVES: Current therapy of brain abscess (BA) includes a combined approach that involves antibiotics and minimal invasive surgery, but also hyperbaric oxygen treatment (HBOT) as a supportive measure. Optimum treatment is still a matter of significant controversy. METHODS: The experiment, previously approved by a relevant ethical committee, involved 80 female Wistar rats. BA was experimentally induced by inoculation of Staphylococcus aureus. The animals were randomized into groups and treated either with antibiotics, HBOT, or with a combination of both. RESULTS: Beneficial effect of HBOT was evident in groups treated with HBOT or with a combination of antibiotic+HBOT. It was mainly manifested on days three and five of the experiment and was evident as statistically significant increase of a number of newly formed blood vessels, increase in mean vascular density, and smaller abscess necrotic core. DISCUSSION: Although the results of the present study should be interpreted cautiously, they suggest that HBOT has an important but limited role in the treatment of BA.

Death of a scuba diver caused by vomiting and panic: a case report.

Scuba diving fatalities are rare and sometimes extremely difficult to explain. A thorough forensic investigation, conducted by a qualified team, helps avoid possible later questions and doubts, family concerns and judicial matters, since a significant body of evidence is lost after the body of the victim is buried or the equipment is reused. We report about a death of a scuba diver who was drowned while diving to the depth of 30 meters. Before being assisted to the surface, the diver panicked and removed the regulator from his mouth. The technical expertise of the scuba gear and the chemical analysis of the air from the high-pressure cylinder revealed no irregularities. Homicide, suicide, nitrogen narcosis, oxygen toxicity, and regulator malfunction were ruled out as possible causes of death. The most probable cause that triggered the event was vomiting into the regulator, as confirmed nearly 4 years later by the toxicological analysis of the traces of matter found in the dry chamber of the breathing regulator. Such an analysis should be considered when investigating suspicious diving related deaths and could be undertaken even after a significant time delay if the equipment is kept properly stored.

Croatian indications for hyperbaric oxygenation: doubts of the world projected in a small country.

The recently issued "Croatian List of Indications for Hyperbaric Oxygen Treatment" (HBO2T) includes indications from the Undersea and Hyperbaric Medical Society List of Indications and the European Consensus List of Indication for Hyperbaric Oxygen, but also several considered by many as "off-label." Now approved by Croatian national health authorities, these indications are no longer "off-label" in Croatia. This represents a real controversy, confronting administrative vs. scientific/professional issues. Few systematic reviews have been published in The Cochrane Library so far on the subject of HBO2T, and most of them did not result in definitive recommendations for clinical practice. Croatian patients might benefit from the current list of indications because they will have the opportunity to be treated at the government's expense. Researchers will have easier access to potential subjects for clinical studies, subjects that are urgently needed to establish whether standard and off-label indications for HBO2T are in accordance with the principles of evidence-based medicine.

[Beliefs of Croatian surgeons and internists on hyperbaric oxygenation--a preliminary report]. / Stavovi hrvatskih kirurga i internista o hiperbaricnoj oksigenaciji--prethodno priopcenje.

BACKGROUND/INTRODUCTION: Hyperbaric oxygenation (HBO) has been accepted in many countries as a method of treatment in selected indications, but in Croatia it is still perceived with skepticism. OBJECTIVE: To determine beliefs, knowledge, and possible experience of Croatian surgeons and internists with HBO. SUBJECTS AND METHODS: An anonymous questionnaire was applied to test surgeons (N=56; 45%) and internists (N=68; 55%), employed in general hospitals in Zadar, Sibenik, Split, and Dubrovnik, Republic of Croatia. We believed that the subjects had been previously exposed to information campaigns about HBO and its clinical applications, and should have been informed about the method at a level enabling correct establishment of indications and routine usage of HBO in clinical practice. RESULTS: The majority of study subjects (N=66; 53%) had very little or no information at all about HBO and half of them (N=50; 40%) had no experience in its application. Almost all (N=123; 99%) subjects considered the method valuable in the treatment of decompression sickness, 56 subjects (45%) considered the method efficient in carbon monoxide poisoning, 31 (25%) in cerebral arterial gas embolism, 87 (70%) in problem wounds, and 70 (56%) in gas gangrene. The only statistically significant difference between the two groups of subjects was recorded in case of cerebral arterial gas embolism (chi2 = 7.26, P = 0.007), which was recognized as an indication for HBO by more internists (N=23) than surgeons (N=8). DISCUSSION: Insufficient understanding of HBO amongst Croatian surgeons and internists is probably the consequence of several factors, of which most important probably are insufficient curricula of undergraduate studies and residencies, as well as administrative obstacles. A small number of responders and polled hospitals necessarily resulted in a significant bias, so additional studies are necessary to shed more light on the issue.

Effects of voluntary fluid intake deprivation on mental and psychomotor performance.

AIM: To assess if there is deterioration in mental and psychomotor performance during 24-hour voluntary fluid intake deprivation. METHODS: A battery of computer generated psychological tests (Complex Reactionmeter Drenovac-series) was applied to 10 subjects to test light signal position discrimination, short-term memory, simple visual orientation, simple arithmetics, and complex motor coordination. We measured total test solving time, minimum (best) single task solving time, total ballast time, and total number of errors. Mood self-estimate scales of depression, working energy, anxiety, and self-confidence were used to determine the emotional status of subjects. During the first day of the experiment, subjects had free access to drinks. After a 48-hour interval, subjects voluntarily abstained from fluid intake for 24 hours. During that period, the testing was performed 7 times a day, at 3-hour intervals, except during the night. Z-transformation of the results enabled the comparison of 50 dependent measurements on the same subjects. RESULTS: During dehydration, there was significant deterioration in total test solving time, minimum single task solving time, and total ballast time. No significant deterioration was found by mood self-estimate scales, except on the scale of energy at 23:00 hours. CONCLUSION: Voluntary 24-hour fluid intake deprivation led to deterioration in objective parameters of psychological processing, but not in subjective parameters. The results suggest that the duration of fluid intake deprivation can be a useful indicator of mental and psychomotor deterioration level but not of mood self-estimates.

[Helicopter transport of patients from Croatian Adriatic Islands and coastal area in the period from 1996 to 2002]. / Helikopterski prijevoz bolesnika s hrvatskih jadranskih otoka i priobalja u razdoblju od 1996. do 2002. godine.

For most of the Croatian Adriatic islands and coastal area, helicopter is the fastest, and for some remote areas the only effective way of patient transport. In Croatia, most of the aeromedical transports are performed by helicopters of 95th Air Force Base. During the post-war period, the number of civilian patients transported with those helicopters increased from 56 in 1996 to 311 in 2002, this trend continuing in 2003. The majority of these transports were performed in the third trimester of the year, the largest number of patients were transported from the Island of Hvar, and the most common medical indication for aeromedical trasport was trauma. The lack of competent medical escort may have unfavourable impact on patient health and flight safety. The increasing trend in requesting aeromedical transport would obviously justify the foundation of a specialized commercial service to provide both safe transport and competent medical escort.

Aerobic exercise before diving reduces venous gas bubble formation in humans.

We have previously shown in a rat model that a single bout of high-intensity aerobic exercise 20 h before a simulated dive reduces bubble formation and after the dive protects from lethal decompression sickness. The present study investigated the importance of these findings in man. Twelve healthy male divers were compressed in a hyperbaric chamber to 280 kPa at a rate of 100 kPa min(-1) breathing air and remaining at pressure for 80 min. The ascent rate was 9 m min(-1) with a 7 min stop at 130 kPa. Each diver underwent two randomly assigned simulated dives, with or without preceding exercise. A single interval exercise performed 24h before the dive consisted of treadmill running at 90% of maximum heart rate for 3 min, followed by exercise at 50% of maximum heart rate for 2 min; this was repeated eight times for a total exercise period of 40 min. Venous gas bubbles were monitored with an ultrasonic scanner every 20 min for 80 min after reaching surface pressure. The study demonstrated that a single bout of strenuous exercise 24h before a dive to 18 m of seawater significantly reduced the average number of bubbles in the pulmonary artery from 0.98 to 0.22 bubbles cm(-2)(P= 0.006) compared to dives without preceding exercise. The maximum bubble grade was decreased from 3 to 1.5 (P= 0.002) by pre-dive exercise, thereby increasing safety. This is the first report to indicate that pre-dive exercise may form the basis for a new way of preventing serious decompression sickness.

[Hyperbaric medicine in Croatia: an example of ethics on probation]. / Hiperbaricna medicina u Hrvatskoj: primjer etike na kusnji.

Hyperbaric oxygenation (HBO) has been existing in the Republic of Croatia for over 30 years, but still carries a burden of many problems: scientific, professional, legal, economical, and ethical. Discussed are ethical aspects dealing with HBO in Croatia, based on the following statements and questions: Croatian doctors have very limited knowledge of HBO; its efficacy in the treatment of many different diseases is in Croatia viewed with skepticism; are there other medical priorities that should be developed as a priority in the country after the war; what controlled, prospective, double blind, clinical studies support the use of HBO; is it a method of high risk; do we need to repeat studies on HBO efficacy already done elsewhere; and how to make Croatian legislation and human rights compatible in this matter.

Esophagotracheal fistula after lithium disc battery ingestion successfully treated with hyperbaric oxygen therapy.

We report a case of a 12-month-old child who acquired an esophagotracheal fistula of 5 mm in diameter after an ingested lithium disc battery impaction. Failure to recognize foreign body on chest X-rays resulted in a delay of 28 days in establishing the diagnosis. Feeding via nasogastric tube and hyperbaric oxygen treatment (HBOT) resulted in a complete closure of the fistula after 17 HBOT 60 min sessions at 2.2 bars.

Scuba diver with a knife in his chest: homicide or suicide?

A scuba diver was found dead at the bottom of an undersea cave at 54.1 m water depth, with a knife protruding from his chest. Autopsy confirmed death due to both drowning and a penetrating knife wound. The incident was first considered a homicide and two suspects were arrested. Careful forensic analysis of the profile of the diver's last dive stored in the dive computer, dimensions of the undersea cave, as well as other forensic findings, showed that the case was a suicide, which the diver most probably committed while running out of air, in an attempt to avoid the agony of drowning. To the best of our knowledge, this is the first report on a suicide during diving.

Differential diagnostic problems of decompression sickness--examples from specialist physicians' practices in diving medicine.

It can be expected that the differential diagnosis problem of decompression sickness will increase in the future due to the increasing number of divers. During the last 30 years, 232 divers were treated for decompression sickness (DCS) at the Naval Medical Institute (NMI) in Split, Croatia. In 66 cases (28%), physicians at various diving sites reached diagnosis with difficulty, and 86 divers (37%) came directly to the NMI without seeing a physician first. Physicians at remote diving locations frequently have only basic knowledge of diving medicine and are often inexperienced. The language barrier was a major obstacle in obtaining a medical history and examination of foreign divers. Consultations at the NMI proved a major contribution to correct diagnosis and treatment. We present six illustrative cases from NMI Archives that demonstrate how prejudices, panic, and inexperience could create problems in establishing DCS diagnosis.

Change of occurance of type 1 and type 2 decompression sickness of divers treated at the Croatian Naval Medical Institute in the period from 1967 to 2000.

A significant change of occurrence (p=0.0343) of type 1 and type 2 decompression sickness (DCS) of divers in Croatia was observed in the period from 1991 to 2002 (type 1: n=26, 37.68% and type 2: n=43, 62.32%) compared with the period from 1967 to 1990 (type 1: n=93, 52.84% and type 2: n=83, 47.16%). The change was attributed to the extensive usage of diving computers and artificial gas mixtures which enable extended bottom times and deeper dives, thus putting divers at an increased decompression risk. The importance of the results of this report is in the fact that permanent neurological deficit occurs only after type 2 DCS. Injured divers with permanent loss after type 2 DCS are not fit for diving and require a long term medical care, thus becoming a significant public health problem.

[Gas gangrene and hyperbaric oxygenation--a lesson forgotten or never learned?]. / Plinska gangrena i hiperbaricna oksigenacija--zaboravljena ili nikad naucena lekcija?

Gas gangrene develops in devitalized hypoxic tissue. It spreads rapidly under strong influence of enzymes produced by the causing bacteria and often results in fatal outcome. It is of utmost importance to stop toxin production as soon as possible, which is most effectively achieved by early application of hyperbaric oxygenation (HBO2), as the first measure in a "trident" (HBO2, antibiotics, surgical measures). The paper reviews the most important data from microbiology, pathophysiology and epidemiology of gas gangrene, current clinical practice, scientific basis for application of HBO2 in the treatment of this disease, and data from the archives of the Naval Medical Institute of the Croatian Navy in Split (NMI). At the NMI, in the period from 1982 to 2000, HBO2 was administered in the treatment of 21 patients with gas gangrene, of average age 41.6 +/- 16.3 years. The average treatment consisted of 6.8 +/- 3.8 sessions. 13 (76%) patients were cured.

Gastric rupture in a diver due to rapid ascent.

A 37-year-old, experienced female diver developed gastric rupture due to rapid ascent from a depth of 37 meters. The incident was preceded by a heavy meal, intake of soda beverages, swallowing of air and water under water, and panic. Sharp abdominal pain was present immediately after surfacing and afterwards. Full abdominal distension developed within two hours after the ascent. No other diving-related pathology was found. Surgery was performed around three hours after the accident and revealed pneumoperitoneum, gastric rupture, gastric content in the abdomen cavity, and signs of acute peritonitis. On surgery, a 4-cm rupture of the lesser curvature was found and sutured. The patient was discharged eight days after the event.