A murine model of latex allergy-induced airway hyperreactivity.

Sensitization to latex proteins can cause immediate IgE mast cell-mediated reactions. Health care workers have been found to be particularly at risk because of high exposure. Latex allergy can be produced in mice as demonstrated by IgE and eosinophil responses. Thus the mouse is a potential animal model for studying this disease, but the airway response to latex sensitization in mice has not been evaluated previously. In the present study, we immunized BALB/c mice intranasally with nonammoniated latex proteins. Animals were anesthetized, and lung mechanics were evaluated plethysmographically. Changes in pulmonary conductance (GL) and compliance (Cdyn) were measured in response to a nonspecific challenge with methacholine or to a direct challenge with intravenous latex antigen. Latex sensitization resulted in elevated levels of IgE and latex-specific IgG1 as well as interstitial infiltrates consistent with an allergic response. The methacholine dose-response ED50 for GL was 116.4 microg for the control mice and fell significantly to 20.9 microg for latex-sensitized mice. The ED50 calculated for Cdyn was also significantly lower after latex sensitization. The GL in latex-sensitized mice challenged with latex antigen fell significantly from a prechallenge value of 1.87 +/- 0.41 (S.E.) to 0. 198 +/- 0.03 ml x s-1 x cmH2O after latex antigen challenge. The results indicate that latex-sensitized mice did exhibit increased airway reactivity in the methacholine challenge test. The latex allergic response in mice is unique in that direct challenge with latex antigen itself also resulted in a significant airway response.

Survival and functional outcome of children requiring endotracheal intubation during therapy for severe traumatic brain injury.

OBJECTIVE: To determine the predictors of survival and functional outcome of pediatric patients with traumatic brain injury severe enough to require endotracheal intubation and mechanical ventilation. DESIGN: Retrospective, observational cohort study. SETTING: Pediatric intensive care unit (ICU) at a tertiary care children's hospital. PATIENTS: All children (n = 105) admitted over a 5-yr period with traumatic brain injury severe enough to require endotracheal intubation and mechanical ventilation. The median age was 43 months (range 1 month to 14 yrs). Of these children, 74% were male and 70% were white. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Variables studied included vital signs during the first 24 hrs of admission, Pediatric Risk of Mortality (PRISM) score, Glasgow Coma Score, duration of mechanical ventilation, and number of pediatric ICU and hospital days. Functional status was graded as normal, independent, partially dependent, or dependent in the areas of locomotion, self-care, and communication. This status was assessed at hospital discharge by chart review and at follow-up by telephone interview. The median Glasgow Coma Score was 6 (range 3 to 14) and the median PRISM score was 13 (range 1 to 51). There were 19 (18.1%) deaths, 17 in the pediatric ICU and two after hospital discharge. Of the patients who survived to hospital discharge, 39 (37.1%) patients were completely normal or independent, 42 (40%) patients were partially dependent, and seven (6.7%) patients were dependent in all three areas of function. Follow-up evaluations were available for 80 patients, with a median follow-up time of 24.5 months (range 8 to 70). Of the 78 patients who survived and were available for follow-up, the number who were functionally normal or independent increased to 69 (65.7%). At follow-up, there were eight (7.6%) patients remaining with partial dependency in at least one area of function while one (0.9%) patient continued to be dependent in all three areas of function. Mortality and dependent functional outcome were more likely in patients with younger age, lower Glasgow Coma Score, and higher PRISM score at hospital admission. Of the 27 patients with a Glasgow Coma Score of < or = 5, 11 (40.7%) survived with normal or independent functional status at follow-up. Of the 24 patients with PRISM scores of > 20, only five (20.8%) were functionally normal or independent at follow-up. The relative risk of a bad outcome for patients with a Glasgow Coma Score of < or = 5 and a PRISM score of > or = 20 was ten times higher than the group of patients with a Glasgow Coma Score of < or = 5 but a PRISM score of < 20. CONCLUSIONS: Children with severe traumatic brain injury who survive to hospital discharge will continue to improve in their functional status over the next few years. Although low Glasgow Coma Score is strongly associated with death or poor functional outcome after therapy for traumatic brain injury, many patients with Glasgow Coma Score of < or = 5 can survive with good function. PRISM scores add to the power of Glasgow Coma Score to predict survival and functional outcome in tracheally intubated pediatric patients with Glasgow Coma Score of < or = 5.