Altitude mountain sickness among tourist populations: a review and pathophysiology supporting management with hyperbaric oxygen.

In the mountain climbing community, conventional prevention of altitude mountain sickness (AMS) relies primarily on a formal acclimatization period. AMS symptoms during mountaineering climbs are managed with medication, oxygen and minor recompression (1524-2438 m altitude) using a portable chamber, such as the Gamow Bag. This is not always an acceptable therapy alternative in a predominantly elderly tourist population. The primary problem with reduced pressure at high altitude is hypoxaemia, which causes increased sympathetic activity, induces pulmonary venous constriction, while increasing pulmonary blood flow and regional perfusion. Rapid assents to altitude contribute to an increased incidence of decompression sickness (DCS). The treatment of choice for DCS is hyperbaric oxygenation, thus, treatment of high-altitude induced hypoxaemia using hyperbaric oxygenation (HBO(2)) is logical. Life Support Technologies group and the Center for Investigation of Altitude Medicine (CIMA, in Cusco, Peru) propose a comprehensive and multidisciplinary approach to AMS management. This approach encompasses traditional and advanced medical interventions including the use of a clinical HBO(2) chamber capable of recompression to three times greater than sea level pressure (3 atmosphere absolute (ATA)). The system uses a series of AMS hyperbaric treatment profiles that LST has previously developed to the US military and NASA, and that take greater advantage of vasoconstrictive effects of oxygen under true hyperbaric conditions of 1.25 ATA. These profiles virtually eliminate AMS rebound after the initial treatment often seen in conventional AMS treatment, where the patient is either treated at altitude, or does not recompress back to sea level or greater pressure (1.25 ATA), but returns directly to the same altitude where AMS symptoms first manifested.

Materialism and food security.

The present studies examined if materialists have an elevated concern about food availability, presumably stemming from a general survival security motivation. Study 1 found that materialists set a greater life goal of food security, and reported more food insecurity during their childhood. Materialists reported less present-day food insecurity. Study 2 revealed that materialists stored/hoarded more food at home, and that obese persons endorsed materialism more than low/normal weight persons. Study 3 found that experimentally decreasing participants' feelings of survival security (via a mortality salience manipulation) led to greater endorsement of materialism, food security as goal, and using food for emotional comfort. The results imply that materialists overcame the food insecurity of their childhood by making food security a top life goal, but that materialists' current concerns about food security may not wholly stem from genuine threats to their food supply.

Values and beliefs of vegetarians and omnivores.

Following the claim by some anthropologists and sociologists that 1 symbolic meaning of meat is a preference for hierarchical domination (C. J. Adams, 1990; N. Fiddes, 1989; D. D. Heisley, 1990; J. Twigg, 1983), the authors compared the values and beliefs of vegetarians and omnivores in 2 studies conducted in New Zealand. They compared the full range of vegetarians and omnivores on right-wing authoritarianism, social dominance orientation, human values, and consumption values. The participants tending toward omnivorism differed from those leaning toward veganism and vegetarianism in 2 principal ways: The omnivores (a) were more likely to endorse hierarchical domination and (b) placed less importance on emotional states. Accordingly, the acceptance or rejection of meat co-varied with the acceptance or rejection of the values associated with meat; that finding suggests that individuals consume meat and embrace its symbolism in ways consistent with their self-definitions.

Decision analysis for the cost effectiveness of sestamibi scintimammography in minimizing unnecessary biopsies.

BACKGROUND: The purpose of this study was to assess if breast cancer screening using sestamibi scintimammography (SSMM) in conjunction with mammography (MM) is cost effective in avoiding biopsies in healthy patients. METHODS: Quantitative decision tree sensitivity analysis was used to compare the conventional MM alone strategy (strategy A) with two decision strategies for screening with SSMM; SSMM after an indeterminate mammogram (strategy B) or SSMM after both a positive and an indeterminate mammogram (strategy C). Cost effectiveness was measured by calculating the expected cost per patient and the average life expectancy per patient for baseline values as well as over a range of values for all of the variables of each strategy. RESULTS: Based on Medicare reimbursement values, strategies B and C showed a cost savings of $9 and $20 per patient respectively as compared to strategy A. This translates into respective savings of $189 and $420 million per year assuming 21 million females undergo screening each year. Strategies B and C did however have a loss of mean life expectancy of 0.000178 and 0.000222 years respectively as compared to strategy A due to interval progression of breast cancer in a small number of women. Strategies B and C significantly lowered the number of biopsies performed on healthy patients in the screening population by 750,063 and 1,557,915 biopsies respectively as compared to strategy A. CONCLUSIONS: These results quantitatively verify the potential utility of using SSMM in avoiding unnecessary biopsies.

The stomach as a microvascularly augmented flap for esophageal replacement.

We present a case of difficult esophageal reconstruction after total esophagectomy for iatrogenic perforation in a diseased esophagus. The stomach was used for esophageal reconstruction as a retrosternal microvascularly augmented flap; the vascular supply to the stomach had been interrupted during previous abdominal operations. The blood supply to the stomach conduit was restored by separate arterial and venous anastomosis between the right internal thoracic vessels and the left gastric vessels.

A study on the cost effectiveness of sestamibi scintimammography for screening women with dense breasts for breast cancer.

The potential impact of Sestamibi scintimammography (SSMM) on the cost effective management of women with dense breasts is not known. This study addresses this issue quantitatively by examining the impact of SSMM based screening strategies on the approximately 3,000,000 women over 40 with very dense breasts (DY patterns) without palpable masses and who have had one or more prior mammograms, who undergo routine screening each year. Quantitative decision tree sensitivity analysis was used to compare the conventional mammography (MM) strategy (strategy A), which does not subject patients with negative mammograms to any further examination until their next screening, with two decision strategies for screening with SSMM; SSMM after a negative mammogram (strategy B) or SSMM as the only screening test for women already identified as having dense breasts by a previous mammogram (strategy C). Cost effectiveness was measured by calculating the incremental cost effectiveness ratio (ICER) of strategies B and C, which is the cost of achieving an additional year of life in the screening population by choosing a SSMM based decision strategy rather than the conventional strategy. Strategies B and C reduced the number of false negative diagnoses by 62% and 8%, respectively. The ICER was $632,000 and $3.18M per life year for strategy B and C, respectively. To be cost effective, the pre-test probability of cancer in the study population must be greater than 3% for strategy B or the cost of SSMM must be less than $50 for strategy C. These results show the ICER of an SSMM based breast cancer screening strategy in the management of patients with dense breasts is not currently within the range (approximately $50,000 per year life saved) of other commonly performed medical interventions that are considered cost effective.

Letters.

SYSTEMIC HYPERBARIC OXYGEN THERAPY HYPOCHLORITE SOLUTIONS.

Small-bowel carcinoid presenting in association with a phytobezoar.

An unusual case of a recurrent, postoperative, small-bowel obstruction is presented. The obstruction was due to a phytobezoar proximal to the site of a primary carcinoid of the small bowel. The radiologic findings of a mobile, intraluminal filling defect and a more distal, fixed mural mass are reviewed. The cause of the recurrent obstruction was likely a "ball-valve" effect of the phytobezoar at the site of stenosis caused by the carcinoid. This case emphasizes the value of small-bowel imaging in repeated small-bowel obstruction.

Detection and estimation of the degree of mitral regurgitation by range-gated pulsed doppler echocardiography.

Sensitivity and specificity of detection of mitral regurgitation was assessed by range-gated Doppler echocardiography. The degree of mitral regurgitation was also estimated by the depth and width of the regurgitant jet detected with Doppler and compared with that assessed by left ventriculography. Of 47 patients with an adequate Doppler study, 24 had no mitral regurgitation by ventriculography. All but one were also negative for mitral regurgitation by Doppler, for a specificity of 96%. Of 23 cases with mitral regurgitation documented by ventriculography, Doppler detected mitral regurgitation in 21, for a sensitivity of 92%. Two cases with mitral regurgitation undiagnosed by Doppler had mild mitral regurgitation due to papillary muscle dysfunction. All cases with rheumatic mitral regurgitation were detected. The degree of mitral regurgitation estimated with Doppler had a high correlation with that determined by ventriculography (r = 0.88, p less than 0.01).

Asymmetric septal hypertrophy in patients on long-term hemodialysis.

Echocardiographic studies were performed in 23 hypertensive patients who were receiving therapy with long-term hemodialysis. Five patients (22 percent) had normal thickness of the left ventricular wall. Eleven (48 percent) had symmetric left ventricular hypertrophy, and seven (30 percent) showed asymmetric septal hypertrophy, with a ratio of septal to posterior wall thickness of 1.3 or greater. The latter group differed from patients with hypertrophic cardiomyopathy in that patients on long-term hemodialysis had a dilated left ventricular dimension, a relatively normal diastolic slope of the mitral valve, absence of systolic motion of the mitral valve, and a septal to posterior wall ratio of less than 1.5. A high incidence of asymmetric septal hypertrophy in this and other studies indicates that this condition is not specific for hypertrophic cardiomyopathy. We suggest that in addition to asymmetric septal hypertrophy, the diagnosis of hypertrophic cardiomyopathy should be made in the light of the clinical picture, as well as other echocardiographic features.

Transient ischemic attacks.

The treatment of TIA must be individualized. TIA is one of several manifestations of generalized atherosclerosis. While one-third of patients with TIA will suffer a stroke in five years, one-half of the same group will die of myocardial infarction. The risk of stroke is greater in carotid rather than vertebral-basilar TIA, in older patients, and in those with a cluster of TIAS, an is highest in the first month after the TIA. Treatment should reflect this knowledge.