RESEARCH FORUM ABSTRACTS

published after 1994; overall, study quality was high but trials were not large (maxi- mum 111 patients). Four trials included only adults; 3 trials included only children. Three studies compared inhaled corticosteroids with corticosteroids; 2 studies com- pared inhaled corticosreroids plus corticosteroids with corticosteroids, and 2 studies compared inhaled corticosteroids alone versus placebo. Various outcome measures were used, including pulmonary function tests, clinical scores, admission rates, and incidence of adverse side effects. Despite the marked differences in study characteris- tics, results suggest a homogeneous decrease in admissions with inhaled corticosteroid treatment (odds ratio 0.46, 95% confidence interval 0.27, 0.79).

Conclusion: Recent interest in the use of inhaled corticosteroids in the ED has led to a number of small studies with disparate study characteristics. Individually, studies have not demonstrated a clear benefit with addition of inhaled eorticosteroids to stan- dard therapy; however, pooled analyses suggest a beneficial effect of inhaled cortico- steroids. To clarify this issue, a large RCT of inhaled corticosteroid use in the ED is needed

32 Intravenous Magnesium Sulfate in the Treatment of Severe Asthma: A Systematic Review of the Evidence

Rowe BH, Michaud J, Bourdon C, Bota GW. Camargo CA Jr/University of Alberta. Edmonton, Alberta, Canada; Sudbury Regional Hospital. Sudbury, Ontario. Canada; Massachusetts General Hospital, Boston, MA

Study objectives: To determine the effect of intravenous magnesium sulfate (Mg) for treatment of patients with acute asthma managed in the emergency department.

Methods: Computerized, hand, and bibliographic searches identified randomized controlled mals (Mg versus placebo); the author contact produced additional studies. Outcomes included pulmonary function tests, admissions, and adverse effects. Selection, data extraction, and quality assessments were conducted independently by 2 reviewers. Studies were pooled using weighted mean differences (WMDs) or odds ratios (ORs) with 95% confidence intervals (95% CIs).

Results: From 91 references, 7 trials were included (5 adult, 2 pediatric): a total of 665 patients have been studied (337 Mg; 328 placebo). Overall, patients recei'.'mg Mg demonstrated nonsignificant improvements in peak expiratory llow rate (PEFR) (WMD=29.4; 95% C1-3.4 to 62) and % predicted FEV t (WMD=4.3; 95% C1-2.3 t o

10.9). For patients with severe asthma, Mg improved both PEFR (WMD 52.3; 95% CI 27 t o 77.5) and % predicted FEV t (9.8; 95% C1 3 8 to 15.8). Likewise, Mg did not significantly reduce admissions overall (OR=0.31; 95% C1 0.09 to 1.02) but did reduce admissmns among severe patients (OR=0.10; 95% C[ 0.04 to 0.27). Mg was generally very well tolerated.

Conclusion: Current evidence does not support the routine use of intravenous Mg in all patients presenting to the ED with acute asthma. However, Mg appears beneficial in patients who present to the ED with severe asthma, and its use should be incorpo- rated into practice guidelines.

33 Edentulism Worsens Obstructive Sleep Apnea

Pivetti S. Navone F, Urbino R, Bonetto C, Colagrande P, Arienti A, Preti G, Carossa S, 6ai V/Medicina d'Urgenza, A 0 San Giovanni Battista, Torino, Italy

Obstructive sleep apnea (OSA) has a prevalence of 2% to 4% in the general popula- tion, but it is estimated that 61% of subjects older than 50 years meet the minimum criteria for OSA (apnea/hypopnea index [AHI] >5), with potentially life-threatening consequences. OSA correlates with diurnal systemic hypertension, bradycardic and tachycardic arrhythmias, sudden death, pulmonary hypertension, and chronic respi- ratory failure Although craniomandibular abnormalities have been recognized as risk factors for OSA, the role of edentulism has never been systematically investi- gated.

Study objectives: We investigated whether edentulism is associated with increased risk for OSA.

Methods: We examined 20 edentulous patients wearing complete mobile dentures. 11 with OSA (7 men and 4 women) and 9 without OSA (3 men and 6 women). The 2 groups had similar age (mean age 64 years) and body mass index. All patients under- went 2 full nights of polysomnography (continuous recording of dectroencephalogra- phy, elecrromyography, electrooculography. ECG. nasal airflow, body position. thoracic and abdominal respirator)" efforts, and ox3,hemoglobin level ISao2]) on 2 con- secutive nights, one with and one without dentures, in randomized order. OSA was

defined as more than 5 episodes of apnea or hypopnea per hour of sleep (AHI >5) The anteropostenor phaD'ngeal wall distance (A-PphwD) with and without dentures was assessed by cephalometry.

Results As shown in the Table, in OSA patients, sleeping without dentures was associated with a significant increase in the AHI (9.4• versus 16.2.12; P<.01), a larger number of apneas (6.9*2.3 versus 18.9.39; P=.02), a larger number of hypop- neas (16.8• versus 31.2• P<.02), lower mean Sao 2 (92.5%.1.4% versus 889%• P<.02). lower nadir Sao 2 (86.8%*1 6% versus 81.4%*2.1%; P<.01) and with a significant decrease in retropharyngeal space (1.40.0.2 cm versus 0.9*0.1 cm; P<.05). AHI was closely related to systemic blood pressure (r=0.77, P<.01), awake Pao 2 (r=-0.63. P<.05) and Paco 2 (r=0.67, P< 05). Sleeping without dentures pro- duced disordered breathing also in patients ~'.athout OSA; in these patients the only significant finding was a higher number of apnea episodes and AHt (P=.05).

Conclusion: These findings indicate that edentultsm may dramatically worsen OSA seventy and favors sleep-disordered breathing. Considering the potentially life-threat- ening consequences of OSA, our findings seem to be of clinical relevance in ED. Edemulism patients at risk for OSA, such as the elderly, obese patients, and snorers, should be advised to wear dentures while sleeping,

Table, abstract 333.

With OSA Without OSA

With Without With Without Variable Dentures Dentures Dentures Dentures

AHI Apneas (No.) Hypopneas (No.) Lowest Sao z {%) Mean Sao 2 (%) A-Pphw (cm) "P<.01. ~P<.O5 *P<.02.

9.4+3.3 16.2_+12" 0.86_+0.27 1.06-+0.4 "f 6.9+_2.3 18.9-Z_3.9' 0.25• 1.13_--K).29 t

16.8+3.1 31.2-+5.8 '~ 2.38_+0.73 5.13+_2.42 86.8+1.6 81.4+2.1" 87.8:1:1.1 85.0+2.9 92.5+1.4 89.8+_1,4" 94.2+0.6 93.8_+0.7

1.4+0.2 0.94,-_0.1 t 1.5_+0.2 1.3_+0.1

34 Inhaled Corticosteroids Versus Cromolyn Among Pediatric Patients Presenting to the Emergency Department With Acute Asthma

Clark S. Smithline H. Rowe BH, Camargo CA/Massachusetts General Hospital, Boston, MA; Baystate Medical Center. Springfield. MA; University of Atberta Hospital. Edmonton, Alberta. Canada

Stud)" objective: To identify factors associated with use of either inhaled cortico- steroids tiCs) or cromolyn among children presenting to the emergency department with acute asthma

Methods: A prospective inception cohort study performed during 1997-1998 as part of the Muhicenter Asthma Research Collaboration. Forty-four North American EDs enrolled 1,184 patients, ages 2 to 17 years, who presented with acute asthma. Patients underwent a structured interview in the ED and another by telephone 2 weeks later For the present analysis, we excluded patients ages 2 to 5 (because ICs are not recommended in this age group) and those not taking either medication.

Results: Dunng the 4 weeks before the ED xasit 182 (59%) were taking lCs and 124 (41%) were taking cromolyn. IC patients were older than those taking cromolyn (11• years versus 10-s years, respectively; P<.01), but did not differ by sex (P>.10). IC patients ,.,.'ere more likely to have public insurance, whereas those taking cromolyn '.,.'ere more likely to have pnvate insurance (P<.05) IC patients also were more likely to report prior use of systemic steroids, intubation, hospital admission during the past year, and recent use of other asthma medications (all P<.05). In a multivariate model. the strongest independent predictors of taking lC.s. compared with cromolyn, were having ever taken systemic steroids (odds ratio [OR]=4 5) and being admitted dunng the past year (OR=2.5~: other significant predictors included increasing age, family income, and parental education. Although pauents taking lC.s had worse chronic asthma, patients taking ICs versus cromolyp did not differ by reporting of "severe"

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RESEARCH FORUM ABSTRACTS

symptoms, initial pulmonary index score, or ED uvatment with ~-agonists or steroids (all P>.10). Nonetheless, IC patients were more likely to receive other asthma medica- tions in the ED (55% versus 35%; P=.O01). Multivariate attalysis showed comparable rates of admission, relapse, and ongoing exacerbation at 2 weeks.

Conclusion: Recent use of ICs versus cromolyn appears to be related to both clini- cal and nonclinical factors. ED patients taking ICs had significantly worse chronic asthma than patients taking cromolyn, but the groups did not differ according to acute asthma severity or clinical outcomes.

335 Therapy on ,ntrapulmonary Shunt Caused hy Pulmonary Contusion

Lee KH, Hwaeg SO, Kim YS, Ahn ME, Cho JH, Oh B J, Kang SJ/VVonju College of Medicine, Yonsei University, Wenju, South Korea

Study objective: The aim of this study was to evaluate the effect of early positive end-expiratory pressure (PEEP) therapy on intrapulmonary shunt caused by pul- monary contusion.

Methods: Sixteen patients who received PEEP therapy for pulmonary contusion from nonpenetrating chest trauma were enrolled. Hemodynamic monitoring and early PEEP therapy was performed in the emergency department. Hemodynamic parameters including pulmonary vascular resistance index and intrapulmonary shunt fraction were calculated, and arterial oxygen tension was measured before and after PEEP therapy.

Results: Arterial oxygen tension decreased with increase of the intrapulmonary shunt fraction (R=0.75). lntrapulmonary shunt reduced from 38.4%+_15.8% to 27.6%• by PEEP therapy at physiologic levels (5 to 10 cm H20) (P<.05). Hemodynamic vari- ables including mean arterial pressure, stroke volume index, and pulmonary vascular resistance were not changed by PEEP therapy Reduction of intrapulmonary shunt frac- tion was associated with increase of arterial oxygen tension (R=0.43).

Conclusion: Our observation suggests that early PEEP therapy reduces intrapul- monary shunt fraction caused by pulmonary contusion.

3 3 6 Does Implementation of an Asthma Pathway Improve the Quality of Care in a High-Volume Emergency Department?

Coculioo GP, O'Connor RE, Reese C/Christiana Cars Health System, Newark, OE

Study objective: Guidelines for asthma treatment have been promulgated in an effort to stem the recent increase in morbidity and mortality. This study was conducted to determine whether use of an asthma critical pathway would improve treatment.

Methods: This study was conducted at an emergency department with 115,000 annual visits. Data were collected prospectively during a 3-month period following implementation of the pathway. Patients younger than 40 years with an ED diagnosis of asthma were eligible. Asthma patients not enrolled in the pathway served as concur- rent controls The pathway intervention consisted of a preprinted order sheet specify- ing serial inhaled bronchodilators (NEBS), serial peak flow measurements (PEER), serial examinations, oral steroids (optional), treatment endpoints, and asthma educa- tion. Outcome measures included proportional physician compliance, time to initial NEB, PEFR use, ED length of stay, and steroid use.

Results: A total of 110 patients were eligible with 30 enrolled in the pathway, and 80 serving as controls. The average triage to nebulizer time was 36 minutes in the pathway group compared with 65 minutes for controls (P<.002). PEFRs were obtained on 92% of pathway patients and 38% of controls (P<.002). The rate of steroid use was 77% in the pathway group compared with 54% for controls (P<.02). The mean ED length of stay was 159 minutes with the pathway versus 167 for controls (P=.7).

Conclusion: Use of the asthma pathway led to a decrease in triage to treatment time and increased use of steroids. Length of stay was unaffected despite time spent on patient training We recommend adoption ol an asthma critical pathway to facilitate improved care and to streamline evaluation of the asthma patient.

37 The Utilization of the Burden Nasoscope in Nasotracheal Intubation: Does It Make a Difference?

Rock TC, Stone CK, May J, Stapczynski JS/University of Kentucky College of Medicine, Lexington, KY

Study objectives: The purpose of this study was to compare the traditional tech- nique of blind nasotracheal intubation and nasotracheal intubation using the Burden Nasoscope, a new device invented to assist in nasotracheal intubation.

Methods: A prospective controlled trial was performed to compare nasotracheal intubation with and without the Burden Nasoscope. Participants included 6 PGY-3, 6

PGY-2, and 6 PGY-I emergency medicine residents, all of whom had previous experi- ence with traditional nasotracheal intubation. Intubations were performed on a self- breathing, practice mannequin using a No. 8 Endotrol-type tube. Each of the participants inruhated the mannequin under a controlled setting without the naso- scope, then again using the nasoscope. Each attempt was timed from the point of entering the nares to successful tracheal intubation. The times were averaged and SDs calculated for each set. The data were then analyzed using the Dunnett's method with

set at .05 to determine statistical difterence. Results: A statistically significant difference was found between the 2 time sets.

Participants successfully intubated the mannequin quicker using the Burden Nasoscope with an average time of 11.9_+9 seconds versus the traditional blind tech- nique with an average time of 18.35+8 seconds.

Conclusion: The Burden Nasoscope appears to significantly reduce the time to suc- cessful intubation in a mannequin model. Further study is needed on patients in the clinical setting to determine the true utility of the Burden Nasoscope.

338 National Emergency Airway Registry(NEAR) Showed Midazolam Significantly Lowers Blood Pressure Compared to Etomidate When Used for Tracheal Intubations

Weissman A, Gutman MB, Sagarin M J, Walls RM/University of Connecticut, St. Francis Hospital, Hartford, C]'; Brigham & Women's Hospital, Boston, MA

Study objectives: To determine whether use of midazolam in tracheal intubations lowers blood pressure significantly.

Methods: The National Emergency Airway Registry (NEAR), a data bank that tracked tracheal inmbations in 26 emergency departments in the United States and Canada between December 1997 and December 1998, was queried. Blood pressure and heart rate were measured before, during, and after intubations in which either midazolam or etomidate was the primary induction agent.

Results: A total of 2,392 patients were entered into the NEAR data bank. Sufficient data were available on 352 patients who received only etomidate and 173 who received only midazolam for sedation or induction before tracheal intubation. Systolic blood pressure (SBP) dropped on average 15 mm Hg in the midazolam group (P<.O01), but remained unchanged in the etomidate group. Furthermore, 12.7% of patients receiving midazolam versus only 4.8% of those receiving etomidate became hypotensive to SBP less than 90 mm Hg (likelihood ratio 3.45). Analysis of specific indications for intubation showed the greatest reduction in SBP when using midaao- lam in patients with CHF (41-mm Hg decrease) and chronic obstructive pulmonary disease (COPD) (38-mm Hg decrease).

Conclusion: Mtdazolam may significantly decrease blood pressure when used for tracheal intubations, especially in patients with congestive heart failure or COPD.

339 Nonigvasive Positive Pressure Ventilation in Acute Respiratory Failure: A Preliminary Experience in the Emergency Department

Urbino R, Antro C, Pivetti S. Tartaglino B, Ferreri E, Bonetto C, 6ai V/Medicina d'Urgenza e P.S. Medicina, ED. A 0 San 6iovanni Battista di Torino, H Molinette, Torino, Italy

Study objectives: To evaluate the efficacy and feasibility of noninvasive positive pressure ventilation (NPPV) in patients with hypercapinc or hypoxemic acute respira- tory failure (ARF) admitted to an emergency department or admitted to an acute med- ical care unit.

Methods: Forty-three patients with ARF (29 males, 14 females; mean age 67 years, range 25 to 91 years) were selected for NPPV according to the following criteria: severe dyspnea at rest, respiratory muscle fatigue, normal menration, normal upper airways, stable hemodynamics and, as for hypercapnic ARE, pH less than 7.35, Paco 2 more than 45 mm Hg, respiratory rate (RR) more than 25 beats/min, and, as for hypoxemic ARF, Pao2/EIo 2 less than 200, RR more than 30 beats/rain. Twenty-five patients (14 males, 11 females; mean age 68 years, range 50 to 91 years) had hypercapnic ARF as a result of chronic obstructive lung disease (COLD); 8 (7 males, 1 female; mean age 77 years, range 73 to 84 years) had cardiogeinc hypercapnic acute pulmonary edema (cAPE); 10 (7 males, 3 females; mean age 55 years, range 25 to 77 years) had severe pneumonia, 2 with hypercapnic ARF.

Endpoints were pH more than 7.35, RR less than 24 beats/min, V T more than 7 mL/kg, decreasing dyspnea and signs of muscle fatigue, Spo 2 more than 90%. NPPV was considered successful if the patient was not intubated and mechanically ventilated. NPPV was considered unsuccessful if the patient was intubated and mechanically venti- lated, as well as became intolerant of mask or died. NPPV, as pressure support ventila-

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