Environmental risk factors in hospital suicide.

Suicide of hospitalized patients is the most common sentinel event reviewed by The Joint Commission on Accreditation of Healthcare Organizations. Shorter lengths of stay, sicker patients, and higher patient to staff ratios challenge the ability of the hospital to maintain safety. Risk factors associated with the physical environment of the inpatient psychiatric unit, cited as the most common root cause of inpatient suicide, may be neglected because evaluation of these factors is generally not included in medical education and training. Minimization of fixtures that can facilitate strangulation and other high risk aspects within the hospital environment is an important element in the prevention of suicide on psychiatric units.

Reversibility of elemental liquid diet-enhanced methotrexate toxicity by refeeding with chow.

The toxic effects of methotrexate administration [20 mg/kg, bolus intraperitoneally (ip)] to rats fed a regular chow diet (n = 10) was compared with results in animals fed an elemental, chemically defined, liquid diet (n = 10) for 7 days. All animals receiving an elemental diet became anorectic and lethargic within 60 hr of methotrexate injection. All animals in this group subsequently developed enteritis and died within 150 hr. There was no clinical evidence of enteritis in rats fed a regular chow diet and mortality as zero in this group (p less than 0.001). In a second study one group of rats (n = 9) was fed a regular chow diet for 7 days; four groups were fed an elemental, chemically defined, liquid diet (n = 9 per group) for 7 days. At 24 hr and 8 hr prior to, or 24 hr after methotrexate administration, one group was refed a regular chow diet; the fourth group was maintained on an elemental liquid diet throughout the study period. All rats fed a regular chow diet survived following methotrexate injection (20 mg/kg, ip). All rats fed an elemental diet throughout the study period died. Those rats refed a regular diet 24 or 8 hr prior to methotrexate injection demonstrated a significant improvement in survival (100% in the 24-hr group, 55% in the 8-hr group). However, those animals refed a regular diet 24 hr after methotrexate injection demonstrated a 100% mortality.(ABSTRACT TRUNCATED AT 250 WORDS)

Alteration of methotrexate toxicity in rats by manipulation of dietary components.

Administration of a chemically defined, elemental diet to rats given 20 mg/kg of methotrexate intraperitoneally has consistently resulted in a 100% mortality from severe enteritis within 156 h. This study examined the importance of specific dietary components in the etiology of this enhanced toxicity. Rats were given their respective diets for 7 days, whereupon methotrexate (20 mg/kg) was given intraperitoneally, and percent of survivors was recorded. Varying the concentration of carbohydrate as polysaccharide (0%, 50%, 100%) (n = 30) had no effect on survival. An increase in the percent of protein as polypeptide (0%, 25%, 50%, 75%, 100%) (n = 50) in the elemental diet resulted in a progressively significant increase in percent survival. Addition of either fat or bulk to this elemental diet had no effect on survivorship. Serum and bile methotrexate levels of rats fed an elemental liquid diet (whether or not all of the protein was provided as polypeptide) were significantly increased from 12 to 72 h (p less than 0.03) compared with rats fed a regular Chow diet. When the protein content of the elemental liquid diet was provided as 100% polypeptide, serum and bile methotrexate levels were significantly lower at 48 h compared with the elemental diet group given 100% of protein as amino acid. Administration of methotrexate to rats fed an elemental liquid diet in which all of the protein is provided as amino acids is extremely toxic to the gastrointestinal tract, probably as a result of delayed clearance of the drug from the systemic circulation and from bile. This toxicity is alleviated by the provision of protein as polypeptide in the elemental diet. No toxicity to the drug is seen at this dose in rats fed a regular Chow diet. If these results are applicable to humans, the use of elemental liquid diets as the only source of enteral nutrition would appear contraindicated in patients receiving methotrexate.

Indirect calorimetry: comparison of hood and mask systems for measuring resting energy expenditure in healthy volunteers.

Controversy exists as to the validity and reliability of hood and mask systems in measuring indirect calorimetry. The purpose of this study was to evaluate the accuracy and reproducibility of repeat measurements of resting energy expenditure (REE) in volunteers. Paired REE measurements were performed in 23 subjects after an overnight fast using hood and mask systems. Lean body mass was calculated from four skinfold measurements and body weight determinations. Data were normalized to body weight and lean body mass and were calculated as percent predicted REE in paired tests taken within 5 minutes on the same subject. No significant difference in mean REE was noted between hood and mask systems. Linear regression analysis showed a strong positive correlation (r = 0.91, p less than 0.001) between hood and mask measurements of REE.

Alteration of chemotherapy toxicity using a chemically defined liquid diet in rats.

Controversy exists as to whether administration of a chemically defined diet alters toxicity to chemotherapy. The purpose of this study was to evaluate toxicity to methotrexate in rats fed a chemically defined liquid diet or a regular chow diet. In the first study, 48 adult rats were randomized to be fed a chemically defined liquid diet or a regular diet for 14 days when methotrexate (25 or 50 mg/kg) was given. All liquid diet rats became anorexic and died within 96 h, while no deaths were observed in rats fed regular diet. When 20 liquid diet and regular diet rats were pair-fed to equalize caloric intake before and after methotrexate administration, similar mortality results occurred. In a second study, methotrexate (50 mg/kg) or saline was given and 60 h later all animals were sacrificed to obtain small bowel luminal cultures and tissue sections for histological evaluation. Administration of the liquid diet altered small bowel flora to predominantly Escherichia coli and Pseudomonas sp. and histology showed severe small bowel mucosal enteritis in comparison with regular diet rats. To evaluate whether the changes in intestinal flora or alterations in drug pharmacokinetics were responsible for the increased mortality, two additional studies were done. Gentamicin (4.8 mg/kg/day) was given p.o. or i.m. to the rats on the chemically defined liquid diet. A significant reduction of intraluminal bacteria occurred, but survival time was not improved in animals receiving antibiotics. When mean serum methotrexate levels were analyzed in non-antibiotic-treated rats, drug concentrations were significantly increased at 24, 36, and 48 h after methotrexate injection in the elemental liquid diet rats compared with chow diet rats. Administration of a chemically defined liquid diet to rats receiving methotrexate increased the occurrence and severity of intestinal enteritis, altered intraluminal bowel flora, and decreased clearance of methotrexate from the serum.

Human energy requirements: overestimation by widely used prediction equation.

Basal energy expenditure accounts for a large component of energy losses, and a clinical estimate of this form of thermogenesis is usually derived from a prediction equation. The most widely used prediction equation was developed in 1919 by Harris and Benedict. The energy requirements of healthy and diseased individuals are often estimated from application of this formula. Using a direct gradient-layer calorimeter and two different indirect calorimeters, our two centers found that the Harris-Benedict equation overestimated basal energy requirements by 10 to 15% (X +/- SD, 12.3 +/- 11%) in 201 studies of healthy men and women. These results raise questions regarding the accuracy of predicting an individual's energy requirements.