Differential expression of alpha 4 integrins on effector memory T helper cells during Bordetella infections. Delayed responses in Bordetella pertussis.

Bordetella pertussis (B. pertussis) is the causative agent of whooping cough, a respiratory disease that is reemerging worldwide. Mechanisms of selective lymphocyte trafficking to the airways are likely to be critical in the immune response to this pathogen. We compared murine infection by B. pertussis, B. parapertussis, and a pertussis toxin-deleted B. pertussis mutant (BpΔPTX) to test the hypothesis that effector memory T-helper cells (emTh) display an altered pattern of trafficking receptor expression in B. pertussis infection due to a defect in imprinting. Increased cell recruitment to the lungs at 5 days post infection (p.i.) with B. parapertussis, and to a lesser extent with BpΔPTX, coincided with an increased frequency of circulating emTh cells expressing the mucosal-associated trafficking receptors α4ß7 and α4ß1 while a reduced population of these cells was observed in B. pertussis infection. These cells were highly evident in the blood and lungs in B. pertussis infection only at 25 days p.i. when B. parapertussis and BpΔPTX infections were resolved. Although at 5 days p.i., an equally high percentage of lung dendritic cells (DCs) from all infections expressed maturation markers, this expression persisted only in B. pertussis infection at 25 days p.i. Furthermore, at 5 days p.i with B. pertussis, lung DCs migration to draining lymph nodes may be compromised as evidenced by decreased frequency of CCR7(+) DCs, inhibited CCR7-mediated in vitro migration, and fewer DCs in lung draining lymph nodes. Lastly, a reduced frequency of allogeneic CD4(+) cells expressing α4ß1 was detected following co-culture with lung DCs from B. pertussis-infected mice, suggesting a defect in DC imprinting in comparison to the other infection groups. The findings in this study suggest that B. pertussis may interfere with imprinting of lung-associated trafficking receptors on T lymphocytes leading to extended survival in the host and a prolonged course of disease.

Difficulties with gum elastic bougie intubation in an academic emergency department.

BACKGROUND: The difficulties with gum elastic bougie (GEB) use in the emergency department (ED) have never been studied prospectively. OBJECTIVES: To determine the most common difficulties associated with endotracheal intubation using a GEB in the ED. METHODS: We conducted a prospective, observational study of GEB practices in our two affiliated urban EDs with a 3-year residency training program and an annual census of 150,000 patients. Laryngoscopists performing a GEB-assisted intubation completed a structured data form after laryngoscopy, recording patient characteristics, grade of laryngeal view (using the modified Cormack-Lehane classification), reason for GEB use, and problems encountered. Data were analyzed using standard statistical methods and 95% confidence intervals. RESULTS: A GEB was used for 88 patients. The overall success rate was 70/88 (79.6%; 95% confidence interval [CI] 71.1-88.0%). The GEB failure rate of the first laryngoscopist was 25/88 (28.4%; 95% CI 21.0-40.3%), with the two most common reasons being: inability to insert the bougie past the hypopharynx in 13 (52%; 95% CI 32.4-71.6%) and inability to pass the endotracheal tube over the bougie in six (24%; 95% CI 7.3-40.7). CONCLUSIONS: The GEB is a helpful rescue airway device, but emergency care providers should be aware that failure rates are relatively high at a teaching institution.

Success of the gum elastic bougie as a rescue airway in the emergency department.

BACKGROUND: The gum elastic bougie (GEB) is a rescue airway device commonly found in the emergency department (ED). However, data documenting its efficacy are lacking in the emergency medicine literature. STUDY OBJECTIVES: To determine the success rate of endotracheal intubation using a GEB and the reliability of "palpable clicks" and "hold-up" in the ED setting. METHODS: The GEB was introduced at our two affiliated urban EDs with a 3-year residency training program and an annual census of 150,000. Physicians were trained in the use of the GEB before initiation of the study. Over the course of 1 year, we conducted a prospective, observational study of GEB practices in the ED. The study population included all adult patients on whom intubation was attempted with a GEB. All emergency physicians attempting intubation completed a structured data form after laryngoscopy, recording patient characteristics, grade of laryngeal view (using the modified Cormack-Lehane classification), and presence of "palpable clicks" and "hold-up." Indications for GEB use in our ED include a difficult or rescue airway and for training purposes. Data were analyzed using standard statistical methods and 95% confidence intervals. RESULTS: In our study period, there were 26 patients on whom intubation was attempted with a GEB. The overall success rate was 20/26 (76.9%; 95% confidence interval [CI] 60.7-93.1%). Among cases where the GEB was used for training purposes (all grade 1 or 2a laryngeal view), six of seven (85.7%) intubations were successful. When the GEB was used for clinically indicated purposes, 14 of 19 (73.7%; 95% CI 53.9-93.5%) intubations were successful. Palpable clicks were appreciated in 11/20 successful intubations (sensitivity 55.0%; 95% CI 33.2-76.8%); there was one false positive (specificity 80%; 95% CI 40.9-98.2%). Of 20 successful intubations, hold-up was deferred in five cases; of 15 remaining cases, hold-up was appreciated in 5/15 (sensitivity 33.3%; 95% CI 9.5-57.2%); there were no false positives (specificity 100%; 95% CI 60.7-100%). CONCLUSIONS: In our ED setting, the GEB had a success rate of 73.7% when utilized as a rescue airway after failed attempts. The characteristics of "palpable clicks" and "hold-up" were unreliable.