Reliability of measured tidal volume in mechanically ventilated young pigs with normal lungs.

OBJECTIVE: This study examined whether volumes can be accurately measured at the expiratory valve of a conventional ventilator using pressure support ventilation and positive end expiratory pressure with software compensation for circuit compliance available in the Servo iota ventilator. DESIGN AND SETTING: Comparison of two methods for measuring tidal volume in an animal laboratory. SUBJECTS: Twenty healthy, intubated, sedated, spontaneously breathing pigs. INTERVENTIONS: Volume was measured in ten neonatal-sized and ten pediatric-sized pigs ventilated with the Servo iota ventilator using pressure support ventilation and positive end expiratory pressure with and without circuit compliance compensation. We compared volume measured at the airway opening by pneumotachography to volume measured at the expiratory valve of a conventional ventilator. MEASUREMENTS AND RESULTS: The use of circuit compliance compensation significantly improved the agreement between the two volume methods in neonatal-sized piglets (concordance correlation coefficient: with circuit compliance compensation, 0.97; without, 0.87, p=0.002). In pediatric-sized pigs there was improvement in agreement between the two measurement methods due to circuit compliance compensation (concordance correlation coefficient with circuit compliance compensation, 0.97; without, 0.88, p=0.027). With circuit compliance compensation off there was positive bias: mean difference (bias) 2.97+/-0.12 in neonatal-sized and 3.75+/-0.38 in pediatric-sized pigs. CONCLUSIONS: Our results show that volume can be accurately measured at the expiratory valve of a conventional ventilator in neonatal- and pediatric-sized animals.

Soy immunotherapy for peanut-allergic mice: modulation of the peanut-allergic response.

BACKGROUND: Allergen-specific immunotherapy (IT) is an effective therapeutic modality to prevent further anaphylactic episodes in patients with insect sting hypersensitivity and is being investigated for peanut allergy. So far, peanut-specific IT has been unsuccessful because of the side effects of therapy. Soybean seed storage proteins share significant homology with the respective peanut allergens. OBJECTIVE: This study was undertaken in mice to investigate whether specific doses of soybean would desensitize peanut-allergic mice. METHODS: C3H/HeJ mice were sensitized to peanut with 3 intraperitoneal (IP) injections of crude peanut extract. The mice were desensitized by IP injections with either crude peanut or soybean extract for 4 weeks, 3 times a week. Controls included placebo desensitization with PBS and naive mice. After 2 weeks of rest, mice were challenged IP with crude peanut extract. Thirty minutes later, symptom scores and body temperatures were recorded. Serum immunoglobulins, peanut-induced splenocyte proliferation, and secreted cytokines were measured before and after desensitization. RESULTS: The clinical symptoms in the soybean- and peanut-desensitized animals were markedly reduced compared with the placebo-treated mice. Specific IgG1 levels to crude peanut were significantly lower in the soy IT group than in the peanut IT group. The cellular response to crude peanut was also downregulated in the soy IT group, as shown by decreased peanut-specific stimulation indices and a cytokine profile skewed toward a T H 1 response. CONCLUSIONS: Soy IT can be used to desensitize/downregulate peanut-specific response in peanut-allergic mice and could provide a new therapeutic intervention for peanut allergy.

Validation of a noninvasive blood pressure monitoring device in normotensive and hypertensive pediatric intensive care patients.

OBJECTIVE: To evaluate the performance and to define limitations of a noninvasive blood pressure monitoring device in the critically ill pediatric population. METHOD: Patients were included in the study if they were admitted to the Pediatric Intensive Care Unit, were between the ages of 1 month and 18 years with wrist circumferences of > or =10 cm, and had an indwelling arterial line. Patients were excluded if their systolic blood pressure differed by > or =7.5% between their upper extremities. The measurements were collected simultaneously with those from an arterial line by a computer interfaced with the noninvasive blood pressure monitoring system and the patient's monitor. Heart rates were calculated from the recorded pulse waveforms of the arterial lines. Comparison analyses were performed via bias and precision plots of the blood pressure and heart rate data in addition to calculation of Pearson's correlation coefficients and concordance correlation coefficients. As a nonparametric method of comparison, the proportion of measurements that differed by greater than 10% was calculated. Results. Blood pressures and heart rates of 20 patients between the ages of 12 months and 17 years were monitored by a noninvasive blood pressure monitor for 30 min per patient. This data collection resulted in 2015 data points for each blood pressure and heart rate for comparison of methods. Concordance correlation coefficients were the following: systolic blood pressure, 0.93; diastolic blood pressure, 0.93; mean blood pressure, 0.94; and heart rate, 0.85. CONCLUSIONS: The noninvasive blood pressure monitor is capable of producing an accurate blood pressure measurement every 12-15 heartbeats in addition to providing a pulse waveform and digital display of the heart rate. Our study showed good agreement between the methods in the normotensive and hypertensive critically ill pediatric population with a wrist circumference limitation defined at > or =11 cm.

Effects of continuous positive airway pressure/positive end-expiratory pressure and pressure-support ventilation on work of breathing, using an animal model.

OBJECTIVE: Evaluate the effects of continuous positive airway pressure (CPAP)/positive end-expiratory pressure (PEEP) and pressure support ventilation (PSV) on work of breathing (WOB). METHODS: With 13 anesthetized lambs we measured WOB with an esophageal balloon and flow signals. All the animals were sedated, intubated, and ventilated, using 2 pediatric ventilators (Servo 300 and VIP Bird). Ventilator settings were CPAP of 0, 5, and 10 cm H(2)O and PSV of 5 and 10 cm H(2)O with PEEP of 0, 5, and 10 cm H(2)O. Data were analyzed with 2-way analysis of variance. RESULTS: With the Servo 300 the total WOB (WOB(T)) increased between CPAP/PEEP of 0 and 10 cm H(2)O (p

Recruitment of Hispanic women to the Women's Health Initiative. the case of Embajadoras in Arizona.

This study examined the use of lay advocates (i.e., women enrolled in a study who advocate to others) to improve recruitment among Hispanic women in the Arizona recruitment sites for a large-scale, national prevention study, the Women's Health Initiative (WHI). We examined whether trained, Hispanic lay advocates (called Embajadoras) brought more women into the study than a matched group of Hispanic and Anglo enrollees in the WHI who were supplied with brochures. Fifty-six Hispanic participants in the WHI were randomized to receive training or no training on advocacy, and continued to meet quarterly for 18 months. Also, 42 Anglo women were assigned to control. All groups received brochures to use for advocating the WHI. The number of women referred and enrolled was tracked as well as other factors expected to influence outcomes. Embajadoras were more successful at referral and enrollment than untrained Hispanic women and more successful at enrollment than untrained Anglo controls. Embajadoras were also found to distribute significantly more brochures than control groups. Therefore, a culturally aligned training program to encourage current Hispanic participants in a clinical trial to advocate the study to others may be an effective way to boost referrals and enrollments. Other potential influences on enrollment or referral success could not be determined due to the small sample size. Further study is needed to examine the best methods to encourage enrollment for women referred to the study.

Usage of supplemental alternative medicine by community-based patients with gastroesophageal reflux disease (GERD).

There is an increasing trend towards alternative medicine usage by the general US population. However, the extent and type of supplemental alternative medicine used specifically by community-based patients with GERD is unknown. A previously validated questionnaire that included questions about patient demographics, 18 types of alternative medicine, and attitudes towards alternative and conventional medicine was utilized. Consecutive patients seen by community-based physicians in Arizona (Tucson, Phoenix, and Flagstaff) and Wisconsin (Milwaukee) for GERD received the questionnaire during the years 1999 and 2000. Patients completed the questionnaire and returned it to the Tucson VA Medical Center by mail. A total of 185 patients were surveyed (82 men, mean age 55.8 years). Of those, 61.6% used alternative medicine for any reason. However, only 3.8% of patients used supplemental alternative medicine for GERD. Females were twice as likely (95% CI, 1.10-3.67) to use alternative medicines for any reason (including GERD). Patients with daily acid regurgitation were 5.75 times (95% CI, 1.03-32.17) more likely than patients with less frequent acid regurgitation to use alternative medicines specifically for GERD. None of the other demographics, health characteristics, or attitudes were predictive of supplemental alternative medicine use for any reason (or specifically for GERD). In conclusion, only a small percentage of GERD patients seen by community-based practitioners use supplemental alternative medicine specifically for GERD symptoms, despite a higher usage of supplemental alternative medicine for non-GERD-related illness. Being female and having acid regurgitation daily were positively associated with alternative medicine usage for GERD.