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Biomedical subjects

A Shupak

Publications and source records attributed to A Shupak.

At least 37 records · Page 2Linked to original sources
PubMed1999

Hyperbaric oxygen therapy for massive arterial air embolism during cardiac operations.

BACKGROUND: Massive arterial air embolism is a rare but devastating complication of cardiac operations. Several treatment modalities have been proposed, but hyperbaric oxygen is the specific therapy. METHODS: The Israel Naval Medical Institute is the only referral hyperbaric center in this country for acute care patients. We reviewed our experience in the hyperbaric oxygen treatment of massive arterial air embolism during cardiac operations. RESULTS: Seventeen patients were treated between 1985 and 1998. Eight patients (47.1%) experienced a complete neurologic recovery; 6 patients (35.3%) remained unconscious at discharge, and 3 patients (17.6%) died. Mean (+/- SD) delay from the end of the operation to hyperbaric therapy was 9.6 +/- 7.4 hours (range, 1-20 hours). This delay was 4.0 +/- 3.4 hours (1-12 hours) for patients who had a full neurologic recovery, 12.8 +/- 7.1 hours (5-20 hours) for patients with severe neurologic disability, and 18.0 +/- 2.0 hours (16-20 hours) for patients who died (1-way analysis of variance; P =.002). The source of variance among the groups mainly resulted from the short delay for patients who experienced complete recovery compared with the other 2 groups (Tukey test). All 5 patients who were treated within 3 hours from the operation and 50% (2 of 4 patients) of those patients treated 3 to 5 hours from operation experienced a full neurologic recovery. With a delay of 9 to 20 hours, only 1 of 8 patients had a full neurologic recovery. The association between outcome and treatment delay was found to be statistically significant (tau = 0.65 with exact 2-sided P value =.0007). CONCLUSION: Hyperbaric oxygen therapy should be administered as soon as possible after massive arterial air embolism during cardiac operations.

Cardiac Surgical Procedures↗
PubMed1999

The effect of low-frequency ultrasound on immersed pig lungs.

Acoustic models suggest that high-intensity, low-frequency ultrasound (US) at 21-31 kHz, could cause damage to divers' lungs. The purpose of the study was to investigate lung tissue changes secondary to water-borne low-frequency US produced by commonly used underwater acoustic beacons (pingers). Explanted pig lungs were immersed and exposed to four different modes of low-frequency US pinger transmission. In each trial, 5 pairs of lungs were exposed to sound and 5 pairs served as controls. One central and one peripheral section were taken from each lung and evaluated microscopically for location and extent of damage. When present, microhaemorrhages were primarily found in a patchy alveolar distribution, as well as in the septal and subpleural regions. Only rare focal microhaemorrhages could be found in the Control Group. The results demonstrate a potential hazard to the immersed lungs of large mammals on exposure to prolonged transmission by commercially available underwater pingers. The relevance of these findings to human exposure should be further evaluated.

Animals↗
PubMed1999

Computerized dynamic posturography and seasickness susceptibility.

OBJECTIVE/HYPOTHESIS: The neural mismatch theory emphasizes the role of conflicting multimodal sensory interactions in producing both motion sickness and the rearrangement process that finally leads to habituation to the adverse motion conditions. If this theory is, indeed, correct, the patterns of the response to the integrated signal from simultaneous multisensory stimulation, characterized by unusual relationships between the senses responsible for spatial orientation, should differ according to motion sickness susceptibility. Computerized dynamic posturography (CDP) provides the opportunity to simultaneously change the interactions between visual, somatosensory, and vestibular inputs, thus giving an indication of the relative importance of these senses in maintaining balance. The objective was to investigate balance strategies in naval crew members with differing susceptibility to sea conditions using CDP. STUDY DESIGN: Cross-sectional, parallel-group design. METHODS: Twenty subjects susceptible to seasickness (SS) and 20 nonsusceptible subjects (NSS), healthy male volunteers aged 18 to 25, were tested using the EquiTest system (NeuroCom, Inc., Clackamas, OR). RESULTS: The SS group exhibited significantly less stability than the NSS group in condition 5 of the sensory organization test (SOT). The ratio of the SOT scores of conditions 5 to 1 (the vestibular organization pattern) was also found to be significantly lower in the SS group. CONCLUSIONS: The results suggest that SS might be more dependent on somatosensory and visual inputs and less on vestibular inputs for maintenance of balance compared with NSS. Higher susceptibility to seasickness might reflect abnormal weighting of sensory modalities during the integration process. This would result in disruption of the integration process required to maintain balance and a sense of orientation in space in conditions producing conflicting sensory inputs.

Adolescent↗
PubMed1999

Effect of the anti-motion-sickness medication cinnarizine on central nervous system oxygen toxicity.

Severe seasickness could pose a serious problem in diving, and anti-seasickness medication should therefore be prescribed for the seasickness-susceptible diver. Cinnarizine may be used as a medication if it does not increase the risk of central nervous system (CNS) oxygen toxicity when diving with closed-circuit oxygen or O2-enriched gas mixtures. Twenty-six male, white Sprague-Dawley rats were exposed to high O2 pressures (507 and 608 kPa) before and after cinnarizine ingestion (3.3 mg.kg-1), until the appearance of the first electrical discharge (FED) in the electroencephalogram (EEG) which precedes the clinical convulsions. Each rat was tested on five exposure protocols (control and cinnarizine at 507 kPa O2, control, cinnarizine, and 15 h starvation as a control for cinnarizine at 608 kPa O2) at intervals of at least 2 days or until the EEG connector became detached (a mean of 3.1 exposures per rat). Latency to the FED increased after cinnarizine ingestion in 16 of the 17 pairs of measurements at 507 kPa O2 (by more than 61%, P < 0.002) and in 17 of the 19 pairs of measurements at 608 kPa O2 (by 36%, P < 0.002). There was no significant effect of 15 h starvation. Cinnarizine can be further considered for use in seasickness-susceptible divers as it does not increase the risk of CNS O2 toxicity.

Animals↗
PubMed1999

Inner ear decompression sickness following altitude chamber operation.

Decompression sickness (DCS) is a known hazard of altitude chamber operation. The musculoskeletal, dermal, neurological and pulmonary manifestations of DCS are well recognized, but inner ear injury has not been reported. We present the unusual case of a medical corpsman suffering from vestibular DCS after an altitude chamber exposure to 25,000 ft. The patient had a good clinical response to hyperbaric treatment, but there was laboratory evidence of mild residual vestibular damage with full compensation. This case suggests that aviation medical personnel should be more aware of the possible occurrence of inner ear DCS among subjects exposed to altitude.

Adult↗
PubMed1998

Hyperbaric oxygen therapy for deep second degree burns: an experimental study in the guinea pig.

Most previous animal studies reporting improved epithelialisation and healing of burn wounds under hyperbaric oxygen (HBO) did not include the conventional treatment with topical antibiotics as part of the protocol, and did not compare the effectiveness of HBO therapy with that of normobaric 100% oxygen (NO). The purpose of our study was to compare the results of combined treatment with HBO + silver sulfadiazine (SS) and those of treatment with NO + SS or SS alone. Deep second degree burns were produced on the depilated backs of 54 guinea pigs using a validated burn protocol. The animals were assigned to three treatment groups: HBO + SS, NO + SS, and SS. Dressings were changed daily. HBO was administered at 2 atmospheres absolute (ATA) for 90 min BID, and NO for 90 min BID. The parameters compared among the groups were laser Doppler flowmetry, and burn wound contracture and re-epithelialisation data derived from computerised planimetry of photographs of the wound. No differences in laser Doppler flowmetry results or the magnitude of contracture were found between the groups. Significantly increased re-epithelialisation was observed under NO + SS starting 10 days after the burn (P = 0.02, ANOVA). This significance stems from the difference between the HBO + SS and NO + SS groups (Tukey test). These data indicate that excessively high levels of tissue PO2 might compromise burn healing, and explain our results. A further study comparing combined treatment using a milder HBO protocol + SS and NO + SS is indicated in the search for the optimal HBO regimen.

Animals↗
PubMed1998

Effect of hyperbaric oxygen on a rat transverse rectus abdominis myocutaneous flap model.

The single-pedicle transverse rectus abdominis myocutaneous (TRAM) flap is frequently associated with partial flap necrosis. Hyperbaric oxygen has previously been shown to increase the survival of skin flaps, although there has been no investigation of possible beneficial effects of hyperbaric oxygen on survival of the TRAM flap. The present study compares the effectiveness of hyperbaric oxygen therapy, normobaric 100% oxygen, a hyperbaric air-equivalent mixture, and no treatment at all (control group), in the prevention of TRAM flap necrosis in a rat model. Forty-eight animals were randomly assigned to one of the four above-mentioned groups. The surviving area of the flap was evaluated 7 days after surgery. The hyperbaric oxygen treatment protocol consisted of five 9-minute sessions breathing 100% oxygen at a pressure of 2.5 atmospheres absolute during the first 48 hours, starting within 1 hour of surgery. The areas of surviving skin paddles ranged from 38.5 percent in the control group to 52.5 percent in the group treated with hyperbaric oxygen. One-way analysis of variance indicated that flap area survival was significantly greater in the hyperbaric oxygen group (F = 2.69, p = 0.05). Tukey's pairwise comparison and the two-sample t test indicated that the group treated with hyperbaric oxygen differed significantly from the control group (Tukey's critical value = 3.8, rejection level = 0.05, t test p = 0.01). Our results suggest that the hyperbaric oxygen treatment protocol used improves survival in the rat TRAM flap. However, the optimal treatment protocol to achieve this objective even in the rat seems to be variable, and further studies are required before extrapolating these data to human applications.

Animals↗
PubMed1998

Hyperbaric oxygen therapy for cutaneous/soft-tissue zygomycosis complicating diabetes mellitus.

A 24-year-old female diabetic patient was hospitalized because of ketoacidosis and a necrotic wound on the hand. Debridement and antibiotic therapy failed to halt the process. After demonstration of Mucor in cultures from the wound, the patient underwent extensive surgery and amphotericin B was administered. When the necrotic process continued despite these measures, adjunctive hyperbaric oxygen (100% O2 at 2.5 ATA for 90 minutes) was administered daily for a total of 21 treatment sessions. She gradually improved, and at 2 months follow-up most of the wound had healed. Although the mortality rate of cutaneous/soft-tissue zygomycosis is markedly lower than that of the rhinocerebral form, morbidity is still considerably high. Successful use of hyperbaric oxygen has been reported in rhinocerebral zygomycosis, and it may have been of benefit in this high-risk patient by preventing local and systemic spreading of the fungus. This report is the first case of the use of hyperbaric oxygen for cutaneous/soft-tissue zygomycosis. It is suggested that hyperbaric oxygen be considered for this indication in diabetic patients as an adjunct to surgery and amphotericin B.

Adult↗
PubMed1998

Hyperbaric oxygen therapy in the pediatric patient: the experience of the Israel Naval Medical Institute.

UNLABELLED: The pediatric patient is to be found in hyperbaric facilities throughout the world, receiving hyperbaric oxygen (HBO) therapy for both life-threatening and chronic diseases. OBJECTIVE: To review the experience accumulated at the Israel Naval Medical Institute in the treatment of pediatric patients. DESIGN: A retrospective analysis and review of all records of patients younger than age 18 years. RESULTS: Between 1980 and 1997, 139 pediatric patients age 2 months to 18 years (mean, 7.7 years) received HBO treatment at the Israel Naval Medical Institute. Of the children, 111 (79%) suffered from acute carbon monoxide (CO) poisoning; 13 (9.2%) were treated after crush injury, traumatic ischemia, or compartment syndrome; 4 (2.8%) had clostridial myonecrosis; 1 (0.7%) had necrotizing fasciitis; 5 (3.6%) had refractory osteomyelitis; 2 (1.4%) had suffered massive air embolism; 2 (1.4%) had purpura fulminans; and 1 (0.7%) suffered from decompression sickness. Outcome, judged by neurologic sequelae, mortality, and extent of soft tissue loss and limb amputation, was favorable in 129 patients (93%). Two patients (1.4%) died, 1 as a result of CO poisoning and the other, gas gangrene; 2 of the patients in the CO group (1.4%) remained with neurologic sequelae, and 6 patients in the acute traumatic ischemia group (4.3%) underwent limb amputation. CONCLUSIONS: We had a favorable experience with 129 of a total 139 pediatric patients treated at our facility for the indications listed. A basic knowledge of HBO therapy is needed to refer the pediatric patient for treatment when indicated. The needs of the pediatric patient, especially the critically ill, require specific skills and equipment inside the hyperbaric chamber. Close collaboration between the pediatrician and the hyperbaric medicine physician is essential to ensure adequate care for infants and children.

Adolescent↗
PubMed1997

Alterations in R-R variability associated with experimental motion sickness.

Motion sickness is a complex integration of responses from multiple physiological systems. Whether the changes that occur during the time course of motion sickness are mediated by the sympathetic or parasympathetic systems is still controversial. The present study evaluates alterations in R-R variability during experimental motion sickness in motion sick and non-motion sick subjects. Ten motion sick subjects and 7 non-motion sick subjects participated in the study. Power spectrum analysis of R-R variation was conducted for all subjects 10 min before a brief vestibular disorientation test (BVDT), for 5-10 min of the test, and 10 min after the test. Subjects were also asked to report their symptoms during the test. The motion sick group showed a significant reduction in the power spectrum density of the R-R interval at the mid and high frequencies during the BVDT test period (BVDT), in comparison with the rest period (Rest). These changes probably indicate a decrease in parasympathetic activity during the time course of motion sickness. The non-motion sick group did not show significant differences at any of the frequencies during BVDT. Power spectrum analysis of the R-R interval provides an objective measure of the autonomic response to experimental motion sickness.

Adolescent↗
PubMed1997

[Hyperbaric oxygen for carbon monoxide poisoning].

Severe cases of carbon monoxide (CO) poisoning from all over Israel are treated at the Israel Naval Medical Institute with hyperbaric oxygen (HBO). Between 1.11.94 and 15.2.95. 24 cases of CO poisoning were treated. Poisoning was usually due to domestic gas-fired heating systems, CO being the only toxin involved. Since delay between termination of CO exposure and arrival at the emergency department averaged 55 minutes, the level of carboxyhemoglobin measured on presentation did not always reflect the true severity of the poisoning. Poisoning was defined as severe and requiring HBO treatment when 1 or more of the following indications was present: evidence of neurological involvement, cardiographic signs of acute ischemic injury, metabolic acidosis, carboxyhemoglobin level greater than 25%, and pregnancy. 20 (84%) recovered consciousness during the course of 1 session (90 min.) of HBO treatment (pO2 2.8 ATA) or immediately thereafter, with resolution of other signs of CO poisoning. 3 required a second treatment session before their symptoms resolved. A patient who arrived in deep coma with severe cerebral edema died. HBO is an important element in the combined treatment of severe CO poisoning. There should be greater awareness of the danger of CO poisoning and the means of preventing it, both among medical staff and the population as a whole, mainly in areas in which cold weather requires use of heating systems, which may be gas-fired.

Carbon Monoxide Poisoning↗
PubMed1997

Helium and oxygen treatment of severe air-diving-induced neurologic decompression sickness.

BACKGROUND: The use of helium and oxygen recompression treatment of neurologic decompression sickness (DCS) has several theoretical advantages over the traditionally used air and oxygen recompression tables that have been confirmed by findings from recent animal experiments. OBJECTIVES: To evaluate the outcome of patients with neurologic DCS who had been treated with a helium-oxygen protocol and to compare it with that of a retrospective control group that was treated with air-oxygen tables. DESIGN: The study and control groups included 16 and 17 diving casualties, respectively. The severity of neurologic DCS was estimated according to a 9-point scale weighting motor, sensory, and sphincter control functions. The study group was treated with a helium-oxygen decompression protocol, and the control group was treated with the US Navy air-oxygen Table 6 or 6A. Persistent residual dysfunction was treated in both groups with daily hyperbaric oxygen sessions, at 2.5 absolute atmospheres for 90 minutes, until no further clinical improvement was noted. SETTING: The Israel Naval Medical Institute (Israel's national hyperbaric referral center), Haifa. RESULTS: Significant clinical score increments were found for both the helium-oxygen- and air-oxygen-treated groups: 2.8 +/- 2.4 (mean +/- SD) and 7.4 +/- 1.1 at presentation vs 7.6 +/- 2.1 and 8.1 +/- 1.5 at discharge, respectively (P < .001 and P = .005, respectively). Although the score at presentation was significantly lower for the helium-oxygen-treated group (P < .001), no difference was found between the groups' average outcome scores. While most of the improvement in the patients in the study group could be attributed to the helium-oxygen treatment and not to the supplemental hyperbaric oxygen, in the control group, no significant difference could be demonstrated between the scores at presentation and at completion of the air-oxygen recompression table. In 5 patients who were treated with the use of the air-oxygen tables, deterioration was observed after recompression. No deterioration or neurologic DCS relapse occurred in the helium-oxygen-treated group. CONCLUSION: The results suggest an advantage of helium-oxygen recompression therapy over air-oxygen tables in the treatment of neurologic DCS.

Decompression Sickness↗
PubMed1997

Thermal status of wet-suited divers using closed circuit O2 apparatus in sea water of 17-18.5 degrees C.

A wet suit may not provide adequate thermal protection when diving in moderately cold water (17-18 degrees C), and any resultant mild hypothermia may impair performance during prolonged diving. We studied heat exchange during a dive to a depth of 5 m in sea water (17-18.5 degrees C) in divers wearing a full wet suit and using closed-circuit oxygen breathing apparatus. Eight fin swimmers dived for 3.1 h and six underwater scooter (UWS) divers propelled themselves through the water for 3.7 h. The measurements taken throughout the dive were the oxygen pressure in the cylinder and skin and rectal temperatures (Tre). Each subject also completed a cold score questionnaire. The Tre decreased continuously in all subjects. Oxygen consumption in the fin divers (1.40 l.min-1) was higher than that of the UWS divers (1.05 l.min-1). The mean total insulation was 0.087 degree C.m2.W-1 in both groups. Mean body insulation was 37% of the total insulation (suit insulation was 63%). The reduction in Tre over the 1st hour was related to subcutaneous fat thickness. There was a correlation between cold score and Tre at the end of 1 h, but not after that. A full wet suit does not appear to provide adequate thermal protection when diving in moderately cold water.

Altitude↗
PubMed1997

Effects on pulmonary function of daily exposure to dry or humidified hyperbaric oxygen.

The purpose of this study was to examine the effects of breathing dry or humidified hyperbaric oxygen on pulmonary function. Pulmonary function tests were performed before and after each of 10 hyperbaric oxygen exposures at 2.5 atmospheres absolute (ATA) for 95 min in a group of 13 patients treated daily by hyperbaric oxygen for problem wounds. Patients breathed dry oxygen during five successive sessions and humidified oxygen during the remaining five. No differences were found between forced vital capacities (FVC) and maximal expiratory flows before and after hyperbaric oxygen exposure while breathing dry or humidified oxygen. Significant differences were found for the changes in the percentage of FVC expired in 1 s (FEV1%) and mean forced mid-expiratory flow rate during the middle half of the FVC (FEF25-75%) on day 1 alone: decrements of 1.42 and 2.96%, respectively, under dry oxygen, vs. increments of 3.93 and 34.4%, respectively, for humidified oxygen. Day-to-day decrements in the percent changes in FEV1% and FEF25-75% were observed while breathing humidified hyperbaric oxygen. These results demonstrate that repeated daily exposure to humidified hyperbaric oxygen abolishes the initial beneficial effect of humidification on peripheral airways flow characteristics.

Adult↗
PubMed1997

Effects of systemic hyperoxia on eustachian tube ventilatory function.

Middle ear negative pressure and effusions, decreased middle ear compliance, and abnormal tympanometry results have been described after diving on oxygen. Middle ear gas hyperoxia has been shown to down-regulate the eustachian tube ventilatory function (ETVF). The purpose of the present study was to investigate to what extent systemic hyperoxia in the face of air-equivalent middle ear gas composition might interfere with the ETVF. ETVF was investigated in four young adult female cynomolgus monkeys by the forced-response and inflation-deflation tests using air while the animals breathed either room air or 100% normobaric oxygen. Higher opening, closing, and steady-state pressures were observed under systemic hyperoxia. The percentage of the applied pressure equalized, and the maximal pressure change on a single swallow in the deflation test were both lower under hyperoxic conditions. The results show that systemic hyperoxia might impair ETVF. This observation adds to our understanding of the pathophysiology of middle ear dysfunction observed after diving on oxygen.

Animals↗
PubMed1996

Nonspecific vertigo with normal otoneurological examination. The role of vestibular laboratory tests.

Vestibular laboratory tests are not generally necessary in the diagnosis of patients with a clear description of vertigo accompanied by positive otoneurological examination findings. The purpose of the study was to investigate the role of conventional vestibular laboratory tests in the diagnosis of patients complaining of nonspecific vertigo, despite their having a documented normal otoneurological examination. The results of the standard electronystagmography (ENG) and sinusoidal harmonic acceleration (SHA) tests of 52 patients referred for ambulatory vestibular laboratory tests due to a nonspecific illusion of movement, but with a normal otoneurological examination, were reviewed. Abnormalities were found in the vestibular tests of 35 patients (67 per cent), 22 of whom (63 per cent) were finally diagnosed as having a unilateral peripheral vestibular lesion, and 13 (37 per cent) benign positional vertigo. These results suggest that a high percentage of patients with nonspecific vertigo and a normal otoneurological examination probably suffer from peripheral vestibular dysfunction, which can be objectively documented by the ENG and SHA tests.

Adult↗