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Four chamber subjects wearing various hydrogel contact lenses underwent hyperbaric exposures to 150 Feet Sea Water (FSWG) with a bottom time of 30 minutes for a total of 24 lens trials. No displacement of the lenses was reported, but bubbles formed in twenty-five percent of the trials. They were not, however, noticed by the subjects and did not significantly affect vision or corneal physiology. Keywords: Divers; Vision; Diving.

Respiratory function (VE, VO2, VCO2, r and PACO2) was measured in tne subjects at rest and exercise during prolonged hyperbaric chamber exposure to 2. 52, 2.82, 4.03, and 7.00 atmospheres absolute (ATA). At 4.03 ATA, the ventilatory response to exercise was found depressed at 150 watts. Increased PACO2 indicated CO2 retention. At 7.00 ATA there was a slight but significant elevation of PACO2 at rest and a depression of the ventilatory response to exercise at both 50 and 125 watts associated with a marked CO2 retention. Arrhythmias were found at 4.03 and 7.00 ATA with workloads of 150 and 125 watts, respectively. At 4.03 ATA, premature atrial contractions (PAC) were noted at 150 watts in two subjects during four separate testing sessions. At 7.00 ATA, PAC's were observed at 125 watts in two subjects. One subject developed premature ventricular contractions (PVC's) during three different tests at 125 watts. Arrhythmias occurred only in those exercise tests which produced a marked CO2 retention at increased pressure.

ABSTRACT Economic models analyze the sensitivity of some of the costs encountered in the eleven under sea pipeline connections on the 34" oil line from Ekofisk to Teesside for hydroball/ hydrocouples, hyperbaric chambers, and one-atmosphere chambers. The economic models are summarized by a graph showing the cost for eleven 34 inch connections as a function of the number of productive work days required per. connection. The results do not prove that one system is better than another, but do show the sensitivity to the day rates and productive work days required for each system. INTRODUCTION Economic models analyze one time costs and day rate charges for three systems. The first model involves hydroball/ hydrocouples installed by a lay barge, by the Arctic Surveyor, and by a vessel larger than the Arctic Surveyor. The eleven Ekofisk installations were made from lay barges and the Arctic Surveyor. This experience is utilized by the models. Other costs relate to equipment costs, protective covers, and inspection programs. Costs for installing eleven connections with a hyperbaric system are developed into the second economic model. Costs for burying the splice piece are included. The eleven Ekofiskpipeline connections are assumed to be riser connections to evaluate the one atmosphere chamber system. The equipment costs and other costs of the Lockheed System are modelled. At the time of this writing, the system is not applicable for mid line connections and therefore could only have been used on five of the eleven Ekofisk connections. This lessens the accuracy of the Ekofisk - Lockheed model. THE EKOFISK OIL .AND GAS PIPELINES The huge reserves of oil and gas discovered in the Ekofisk field by the Phillips Norway group in 1969; and later increased by the discovery of six adjoining fields, could only be economically transported by pipeline. This decision has resulted in the construction of two of the largest and longest marine pipelines ever to be built as shown in Figure 1. The large capacity of each line has also required the construction of two intermediate booster platforms on each of the pipelines, believed to be the first ever constructed. Phillips Petroleum Company Norway, operators of the Phillips Norway Group, acting on behalf of the Norpipe A/S, has completed the oil pipeline and is entering the final stages of completion of the gas pipeline. During 1973 and oil and gas pipeline; of this amount, 464 miles were marine pipeline. The 34" o.d. 220 mile oil pipeline from Ekofisk to Teesside, England has a capacity of one million barrels per day and the 36" o.d. 275 mile gas pipeline from Ekofisk to Emden, Germany, has a capacity of 2.28 billion cubic feet per day. Both the oil and gas pipelines are owned by Norpipe A/S a 50-50 joint venture of the Phillips Norway Croup and Statoil, the Norwegian national oil company.

The MK 16 Underwater Breathing Apparatus (UBA) was evaluated to assess its breathing characteristics, duration and technical characteristics at 150 FSW on N2-O2 and 300 FSW on He-O2 in the Navy Experimental Diving Unit Ocean Simulation Facility Hyperbaric Chamber Complex. The oronasal pressures, inspired and expired oxygen and carbon dioxide, electronic oxygen control and failure warning system function were monitored. The results indicate that the oxygen alarms function well, breathing resistance is acceptable at both depths, and the canister durations were adequate for mission support. The electronic control of oxygen was consistent, but the UBA is unreliable because of oxygen valve malfunction and erratic water-tight seal integrity. Additionally, the high negative static load experienced in the horizontal or head-down position caused extreme diver discomfort.

In recent years there has been an increased emphasis on ocean exploration by both government and private agencies of the world. A large portion of these marine activities involve human occupancy of pressure vessels, also known as hyperbaric chambers. The most common chambers of this type are diving submersibles and diver decompression chambers. As their' use by private agencies has grown, so has the requirement that the marine construction codes include more definitive guidelines in design and production of windows for the occupants to view thru the chamber walls.© (1980) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Two simulated saturation dives were conducted to monitor the physiological and biochemical responses of a model animal system to long-term diving in compressed air. The dives were performed at 50 and 60 feet of sea water for 60 and 36 days, respectively. Mean chamber CO2 was 0.42% and 0.33% surface equivalent concentration for the 50- and 60-foot dives, respectively. Mean chamber O2 was .51 ata and .58 ata for the 50- and 60-foot dives. No significant animal mortality was noted in either dive during which time over 825 male albino rats were exposed to pressure. The success of these two dives demonstrated the efficacy of long-term animal diving as a model system for investigation of the biochemical and physiological aspects of compressed air saturation diving.

A new portable clinical suction device has been developed, which operates from compressed gas. Its performance was evaluated and found to equal that of typical electric rotary aspirators and to far exceed the performance of conventional Venturi devices or foot-powered pumps. It can achieve 27 in./Hg. vacuum, has no moving parts, requires little maintenance and incorporates a suction tip, off-on trigger, vacuum control and vacuum release in an easily handled pistol grip.

To the Editor:— The communication, "The Crisis in General Practice: A Grass-Roots Reaction," by Dr. G. R. Foster, Jr., in the March 14 issue ofThe Journal( 187 :797), stirs a grassroots reaction from this quarter. Dr. Foster's implication that, by its nature, medical specialization leads to waste of the patient's money through unnecessary investigations (p 800, first paragraph), is astounding, if true, and certainly needs substantiation. There are many potentially remediable or at least treatable conditions discoverable by periodic and careful examinations by trained specialists. Early treatment of conditions revealed by special examinations may spare the patient literally thousands of dollars in care at a later time. It is true, of course, that the costs of medical care are rising. Directcurrent defibrillators, body plethysmographs, cardiac monitors, heartlung machines, image intensifiers, well-counters, and hyperbaric chambers cost money. But, can anyone estimate how much a salvaged life is worth? There is

Caisson disease or decompression sickness has long been recognized as a hazard of rapid reductions in environmental pressure whether these reductions occur on return to normal atmospheric pressure from high pressure environments or as a result of reductions in pressure by real or simulated ascents to high altitudes. With the increasing use and availability of medical hyperbaric chambers, the effects of increased atmospheric pressure and subsequent decompression on medical personnel have become more important. The risk of hyperbaria may be greater for medical personnel since this group differs in many respects from the highly selected groups employed in diving, caisson work, and high altitude flying. There have been no previous reports of the incidence and severity of symptoms of dysbarism and decompression sickness occurring during the operation of medical high-pressure chambers. Scattered brief comments have indicated that decompression sickness does occur among chamber personnel. 1,2 The characteristics of decompression sickness

Flat disc acrylic plastic windows have been designed, fabricated, evaluated and delivered to experimental diving unit for replacement of glass windows used to date. The large and the small windows have been found on the basis of an extensive evaluation program to be more than adequate for man-rated service under 450 psi maximum operational pressure in steel flanges with diameter of opening in flange of 5.000 and 3.000 inches. All windows were proof tested to 675 psi pressure at 120 F ambient temperature prior to delivery.

[EN] This paper presents a wireless ZigBee-based system to replace the traditional wired communication link of the hyperbaric chambers, which allows reducing the costs of seals capable of withstanding the internal pressures and giving rise to a more versatile system. The system is able to capture and process individual vital signs like the electrocardiography signal, and other four analogue sources, sending the data to an external computer allowing analysis, representation and sharing them with the medical staff. This work solves problems such as the attenuation of the signal produced by the metal walls of the hyperbaric chamber obtaining a coverage area big enough to manage up to six patients with an effective data rate conversion of 2kHz. Furthermore, a battery-based and multi-parameter platform is designed for multi-patient hyperbaric chambers.

The US Air Force hyperbaric chambers are used for treatment of the four disorders generally accepted as amenable to recompression or hyperbaric oxygenation. Ninety-four patients suffering from decompression sickness, air embolism, carbon monoxide intoxication, or gas gangrene have been treated. Forty-seven were military patients or their dependents, and 47 were civilians. The USAF series of 23 patients with surgically, bacteriologically proved spreading, diffuse clostridial myonecrosis brings the literature total of proved cases in patients treated with hyperbaric oxygenation during the past 11 years to 267. Recognized and treated early with a combined hyperbaric oxygen-debridement-antibiotic and supportive program, survival rates of those with gas gangrene should improve significantly.

THE PERPLEXING dilemma of whole-organ procurement and storage is not the least of the problems associated with transplantation procedures. Previously we reported successful preservation in vitro of canine whole organs by combined hypothermia and hyperbaric oxygen for periods up to 48 hours. 1,2,3 The temperature for these studies was maintained fairly constant between 2 to 4 C, while the hyperoxia varied from 3.0 to 8.0 atmospheres, the higher pressure generally being associated with extension of storage from 24 to 48 hours. A notable exception was the invariable finding that the lung would less tolerate in vitro exposure to hyperbaric oxygen above 3.0 atm for any period. 4 This observation formed the framework for further investigation. Materials and Methods Method of Organ Preservation —A commercially available organ-preservation unit manufactured to our specifications (providing both hypothermia and hyperbaric oxygenation) was used. This unit has three hyperbaric chambers, each with a volume capacity