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Biomedical subjects

Y Melamed

Publications and source records attributed to Y Melamed.

At least 109 records · Page 6Linked to original sources
PubMed1987

CNS oxygen toxicity in oxygen-inert gas mixtures.

Central nervous system oxygen toxicity in hyperbaric oxygen-inert gas mixtures was studied by exposing male rats to various gas mixtures having the same oxygen partial pressure and varying pressures of inert gases. The duration of the latent period until the appearance of electrical discharges in the electroencephalogram was used as the criterion for the sensitivity to CNS oxygen toxicity. Two hundred and twenty rats with chronically implanted cortical electrodes were subjected to a single exposure to 1 of 11 different gas mixtures at ambient pressures ranging from 5 to 10 ATA. All gas mixtures had a constant oxygen partial pressure of 5 ATA and varying pressures of inert gas (helium or nitrogen). The duration of the latent period was found to be significantly different in the 11 experimental groups (P less than 0.001). While increasing the inert gas pressure, the latency gradually shortened, reaching the lowest values in mixtures of 5 ATA oxygen and 3 ATA of either inert gas. On further increase in the inert gas pressure up to a total ambient pressure of 10 ATA, the latency returned to control (pure 5 ATA oxygen) values. No difference was found between nitrogen and helium of equal partial pressures. These findings suggest that the risk of CNS oxygen toxicity in gas mixtures is not determined solely by the PO2, and even a relatively low pressure of inert gas can contribute to the imminence of hyperbaric-oxygen-induced seizures.

Animals↗
PubMed1986

The effect of hyperbaric oxygen on acute experimental sulfide poisoning in the rat.

In order to evaluate the efficiency of hyperbaric oxygen in experimental acute sulfide poisoning, we studied the effect of 1 ATA (atmosphere absolute) oxygen and sodium nitrite therapy. We then studied the effect of oxygen at 3 ATA alone and in combination with intraperitoneal sodium nitrite injection on rats poisoned by intraperitoneal injection of LD75 sulfide. Electroencephalogram and heart rate were continuously monitored. We also studied the effect of sodium nitrite and hyperbaric oxygen administered before the poisoning (protective effect). In our experimental set, death of untreated poisoned animals occurred within 5 min. There is a parallel between modification of the EEG pattern and apnea. Respiratory arrest always preceded cardiac arrest. Pure oxygen (1 ATA O2) is effective in preventing death in experimental sulfide poisoning. 3 ATA oxygen was significantly more effective in preventing death than 1 ATA oxygen, or sodium nitrite alone. The best therapeutic regimen was a combination of 3 ATA oxygen and sodium nitrite administration.

Animals↗
PubMed1986

Necrotizing fasciitis.

Necrotizing fasciitis was diagnosed in 16 patients during the years 1980 to 1984. All patients were managed by a uniform protocol consisting of radical excisional surgery, intravenous antibiotics, and hyperbaric oxygen therapy. An overall mortality rate of 12.5% was achieved. In view of the encouraging results, this therapeutic regimen is highly recommended.

Adult↗
PubMed1986

CNS oxygen toxicity in the rat: role of ambient illumination.

The effect of ambient illumination on sensitivity to CNS oxygen toxicity was studied in awake male rats. Continuous recording of the EEG was obtained with chronically implanted cortical electrodes. The appearance of the electrical discharges in the EEG was used as an end point for CNS oxygen toxicity. It was found that sensitivity to CNS oxygen toxicity was inversely related to the level of ambient light illumination. The latent period for appearance of the electrical discharges was significantly shorter in darkness than in light over most of the oxygen pressures. Rats with severely depressed retinal function were as sensitive to oxygen at high pressure as normal rats in darkness, demonstrating the importance of visual input in the modulation of sensitivity to CNS oxygen toxicity.

Animals↗
PubMed1985

Hyperbaric oxygen therapy for Fournier's gangrene.

Soft-tissue infections with tissue necrosis, due to mixed aerobic and anaerobic organisms, are an accepted indication for hyperbaric oxygen (HBO) therapy. A unique type of such infection is Fournier's gangrene. This condition represents a serious risk to life and patients should be treated rapidly and aggressively. We treated three such cases by HBO. All three patients recovered from the infection, although one died later from renal and pulmonary complications.

Adult↗
PubMed1985

Diving and chronic spontaneous pneumothorax.

Diving and pneumothorax cannot go together. An air bubble between the visceral and the parietal pleura will change its size according to Boyle's law, and pneumothorax might increase in size during the ascent from a dive. We would like to present the case of a professional diver, who was engaged in active diving for a period of five months during which time he made 80 to 85 dives with pneumothorax. As far as we know, this is the first such case published in the medical literature. We should also like to emphasize the protracted nature of the pneumothorax, which persisted for that time without changing size. This diver had no medical problems with diving, and the deeper he descended, the better he felt. No tension pneumothorax ever occurred and the diagnosis was made by chance.

Adult↗
PubMed1984

Hyperbaric oxygen therapy for gas gangrene casualties in the Lebanon War, 1982.

Four gas gangrene casualties from the Lebanon War, 1982, were treated with hyperbaric oxygen (HBO). Myonecrosis was diagnosed in three and intraabdominal spread of clostridial infection in one. In all four cases, HBO treatment, in combination with meticulous but conservative surgical debridements and proper antibiotic coverage, was begun within 24 h of diagnosis. HBO therapy was terminated when bacteriostasis was attained, as evidenced by no further spread of myonecrosis and the alleviation of systemic toxic symptoms. All four patients recovered from the clostridial infection, but one died later from other causes. HBO therapy enhances the survival rate of patients with gas gangrene, lowers the anesthetic risk, allows for maximal tissue preservation and helps avoid radical mutilating surgery.

Adolescent↗
PubMed1983

Arterial air embolism after penetrating lung injury.

We present a case of cerebral air embolism after a gunshot wound to the lung, combined with mechanical ventilation. Hyperbaric and pharmacologic therapy resulted in complete recovery. The discussion focuses on hyperbaric therapy as the mainstay of treatment, the importance of prophylactic measures, and prompt diagnosis.

Adult↗
PubMed1983

Factors affecting ventilatory lung function in young Navy selectees.

Ventilatory lung function was studied in 528 Navy selectees 16 to 23 yr of age. Analysis of the pulmonary function data indicated that height and chest circumference were the best "predictors" of forced vital capacity (FVC) and forced expiratory volume in one second (FEV1). Other factors, such as amount of sports activity, ethnicity, weight, or Quetelet index, were of minimal predictive value. Linear prediction formulas of ventilatory lung function for young male adults of this age range were derived. Analysis of variance showed that the apparently greater FVC found in smokers than that found in nonsmokers was related to the smokers being older and consequently taller than the nonsmokers. After adjusting for age (even in this narrow age range) and height, no difference in pulmonary function between the 2 groups could be demonstrated.

Adolescent↗
PubMed1983

Saturation recompression therapy in a diving accident.

We report a case of cerebral air embolism caused by pulmonary barotrauma in a diver. Severe neurological symptoms, deterioration during decompression, and a prolonged, complicated, initial pressure profile indicated the need for saturation therapy. Few clinical cases treated by saturation recompression therapy (SRT) have been reported since its introduction in 1978 (1,5). SRT is an effective alternative for the management of complicated and persistent accidents involving intravascular bubbles.

Adult↗
PubMed1981

The transportable recompression rescue chamber as an alternative to delayed treatment in serious diving accidents.

This report summarizes experience in the use of a Transportable Recompression Rescue Chamber (TRRC) for one man in the rapid initiation of treatment and evacuation in severe scuba diving accidents. An evacuation system is described which incorporates the centralized management of all diving accidents and standardized TRRCs capable of interlocking under pressure with the stationary medical chamber. Oxygen breathing capability in the TRRC allows the use of up-to-date U.S. Navy oxygen treatment tables. Included are 19 cases of Type II decompression sickness and pulmonary barotrauma with neurological manifestations, most of which occurred at remote diving sites with no nearby walk-in chambers. Case analysis includes distance and means of evacuation, delay in initiating therapy, time spent in TRRC, and initial and final outcome. Together, TRRCs and airborne evacuation to a stationary medical chamber insures a minimal delay between the onset of symptoms and the start of recompression therapy. The use of the TRRC is a prime factor in minimizing delay. No complications associated with the use of TRRCs have been encountered. Ideally, evacuation should be made in a pressurized two-compartment (for a victim and an attendant) chamber. However, if this is not available we strongly advocate the use of one-man pressurized TRRCs over unpressurized evacuation.

Barotrauma↗