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The prehospital administration of intravenous methylprednisolone lowers hospital admission rates for moderate to severe asthma
ORIGINAL ARTICLES THE PREHOSPITAL ADMINISTRATION OF INTRAVENOUS METHYLPREDNISOLONE LOWERS HOSPITAL ADMISSION RATES FOR MODERATE TO SEVERE ASTHMA Barry Knapp, MD, Chris Wood, PA, NREMT-P the prehospital setting was 15 6 7 minutes (95% CI = 7–22). The average time elapsed in the emergency department before methylprednisolone was 40 6 22 minutes (95% CI = 23–57). Only 12.9% (4) of the patients receiving prehospital solumedrol were admitted versus 33.3% (11) of those receiving the medication in the emergency department (p = 0.025). Patients were 3.375 times more likely to be admitted if they received methylprednisolone in the emergency department versus in the prehospital setting. Conclusion. Patients with moderate to severe asthma who receive intravenous methylprednisolone in the prehospital setting have significantly fewer hospital admissions. Key words: asthma; corticosteroids; Solu-Medrol; methylprednisolone; prehospital; emergency medical services.
ABSTRACT Objective. To compare hospital admission rates for patients with moderate to severe asthma who receive intravenous methylprednisolone given in the prehospital setting versus in the emergency department. Methods. A retrospective chart review was used to identify emergency medical services (EMS) transports of patients with moderate to severe asthma when 125 mg methylprednisolone was given intravenously in the prehospital setting under existing regional protocols. Data were collected on EMS runs in an urban/suburban system from May 1, 2000, through April 30, 2001. Only patients 18 to 50 years old with a history of asthma were included in the study. Patients were excluded if they left against medical advice, were long-term smokers, used home oxygen, or had a history of chronic obstructive pulmonary disease. A parallel search was performed from February 1, 1999, to April 30, 2000, to identify moderate–severe asthmatics who were transported by EMS and later given intravenous methylprednisolone in the emergency department. During this period, methylprednisolone was not available for use in this EMS system. Results. A total of 31 moderate to severe asthmatics were identified as receiving prehospital methylprednisolone. A total of 33 asthmatics were identified who were transported by EMS and later received intravenous methylprednisolone in the emergency department. Average patient age in the prehospital methylprednisolone group was 34 6 10 years (mean 6 standard deviation; 95% confidence interval [CI] = 31–37). Average age in the hospital group was 34 6 10 years (95% CI = 31– 37). Average time to administration of methylprednisolone in
PREHOSPITAL EMERGENCY CARE 2003;7:423–426
Despite advances in the treatment of asthma, mortality has tripled over the last two decades. In 1995, over 5,000 deaths were reported. Annually the disease accounts for over two million emergency department (ED) visits.1 Therapies for treatment are aimed at reversing bronchoconstriction, decreasing secretions, and reducing inflammation. Treatment recommendations from the National Asthma Education Program in the United States,2 the Canadian Association of Emergency Physicians,3 and the British Thoracic Society4 include the use of beta-agonists and systemic corticosteroids. Although the timing and frequency of treatment regimens can be quite variable in the ED, these two medications have become the mainstay of current asthma therapy. Although widely used, the literature addressing the efficacy of early parenteral corticosteriod use in the ED has been somewhat controversial. Prehospital studies on steroid use for acute asthma are, for the most part, nonexistent. It has been argued that because steroids act at the cellular level, their beneficial effects are not clinically evident for hours after administration.5 Even with the potential for delayed clinical effects, it is the
Received November 4, 2002, from the Department of Emergency Medicine (BK), Eastern Virginia Medical School, Norfolk, Virginia; and Emergency Physicians of Tidewater (CW), Virginia Beach, Virginia. Revision received May 24, 2003; accepted for publication May 27, 2003. Address correspondence and reprint requests to: Barry Knapp, MD, Raleigh Building, Room 304, Department of Emergency Medicine, Eastern Virginia Medical School, Norfolk, VA 23507-1999. e-mail:. doi:10.1197/S1090-3127(03)00211-9
423
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PREHOSPITAL EMERGENCY CARE OCTOBER / DECEMBER 2003
practice of most clinicians to administer steroids as early as possible in moderate and severe asthma attacks. The most recent evidenced-based review by Rowe et al. supports this practice.6 This Cochrane review concluded that corticosteroid administration within one hour of arriving at the ED significantly reduces hospital admission for patients with an acute exacerbation of asthma. The benefits appeared greatest in patients with more severe asthma and in those not currently receiving steroids. Rowe et al.’s review is consistent with earlier systematic reviews that also support the early use of corticosteroids in the ED.6,7 Even widely accepted ED therapeutic practices are often slow to transition into the prehospital setting. It was not long ago that studies were undertaken to determine if prehospital personnel could safely administer beta-agonists that previously were accessible only on arrival in the ED. There is little doubt that prompt treatment of the asthmatic can often halt disease progression. The prehospital setting provides just such an opportunity for early intervention. We sought to determine if intervention with intravenous corticosteroids in the prehospital setting decreased hospital admission rates for patients with an acute exacerbation of asthma.
METHODS Institutional review board (IRB) consent was obtained for this review. This study was a quasi-experimental historical cohort comparison of asthma patients transported by ambulance to an ED who were experiencing an acute exacerbation of asthma. Before the addition of corticosteroids to our ambulances, standard therapy for asthmatic patients included the serial administration of 2.5 mg albuterol in 3 mL of normal saline via a nebulizer. The use of intravenous methylprednisolone (Solu-Medrol) for moderate to severe asthma was implemented in the Tidewater Emergency Medical System in April 2000. Medics were educated on the indications, dosage, and potential side effects of the medication. Based on current local emergency physician (EP) practice, a parenteral dosage of 125 mg was used. A regional protocol was established to guide its use. According to the protocol, once an asthmatic patient is identified, a nebulized treatment of albuterol is administered. If the patient fails to improve clinically or worsens after the initial albuterol treatment, he or she is considered by the protocol to have a moderate to severe asthma attack. The prehospital care provider then may consider intravenous methylprednisolone. An EP via radio must concur with the paramedic’s assessment and then give the order to administer 125 mg methylprednisolone intravenously. A retrospective chart review was preformed at two Tidewater area EDs from May 1, 2000, through April
VOLUME 7 / NUMBER 4
30, 2001, to identify asthmatic patients who were administered intravenous methylprednisolone in the prehospital setting. Sentara Norfolk General Hospital ED has an annual volume of 53,000 patient visits and functions as a level I trauma center. Sentara Virginia Beach General ED is a level II trauma center with an annual volume of 53,000 patients. A parallel retrospective chart review was done for the year prior to the addition of methylprednisolone to our ambulances to identify those asthmatic patients who were transported via ambulance and later were administered 125 mg methylprednisolone intravenously in the ED. Patients included in the study must have had a previous diagnosis of asthma. Only patients aged 18 to 50 years old were included to increase the likelihood that their primary respiratory disease was asthma. Patients were excluded from the study if they left the ED against medical advice or were admitted to the hospital for reasons other than their asthma. Patients with a greater than 20 pack-year history of smoking or on home oxygen therapy were excluded because of their decreased ability to respond to beta-agonists.2 The statistical package used to analyze the study data was the SPSS Student version 9.0 for Windows (SPSS Inc., Chicago, IL). Fisher’s exact test was used to compare the two groups. Because prior literature overwhelmingly supports the early use of corticosteroid in the treatment of asthma, a one-tailed test was used. Results were considered to be statistically significant if the p-value was less than 0.05.
RESULTS A total of 1,546 asthma patient charts were reviewed. Sixty-four patients met the inclusion criteria. Thirtyone patients had been given methylprednisolone in the prehospital setting and 33 after arrival in the ED. The average age of the patients in the prehospital methylprednisolone group was 34 6 10 years (mean 6 standard deviation; 95% confidence interval CI = 31–37). Average age in the hospital group was 34 6 10 years (95% CI = 31–37). There was no statistically significant difference in the ages of the two groups (p = 0.85). The average time to administration of methylprednisolone in the prehospital setting was 15 6 7 minutes (95% CI = 7–22) with a range of 5 to 30 minutes. The average time elapsed in the ED before methylprednisolone was given was 40 6 22 minutes (95% CI = 23–57) with a range of 15 to 101 minutes. In the prehospital methylprednisolone group, 13% (4) of the patients were eventually admitted to the hospital. Of those who received methylprednisolone in
Knapp and Wood
PREHOSPITAL METHYLPREDNISOLONE
AND
TABLE 1. Patient Disposition
Discharged Admitted
425
HOSPITAL ADMISSION RATE
Prehospital Methylprednisolone
Emergency Department Methylprednisolone
27 4
22 11
the ED, 33% (11) were admitted (p = 0.025). Data are summarized in Table 1.
DISCUSSION This is the only study to date demonstrating that patients with moderate to severe asthma might benefit from the administration of prehospital intravenous corticosteroids. This seems a logical assumption if one concurs with current evidenced-based reviews that advocate the early ED administration of intravenous corticosteroids.6–8 The exact pathophysiological mechanism of rapid clinical improvement is not clearly understood. Lin et al. demonstrated significant rapid improvement in the peak flow of patients who received intravenous methylprednisolone.9 Our patient inclusion criteria were similar to theirs. To identify patients with moderate to severe asthma, only those who failed to improve with an initial dose of albuterol were included in our study. Although peak flow rates improved, Lin et al. were not able to demonstrate a statistical difference in admission rates for intravenous corticosteroids versus placebo. This likely reflects the fact that their study was powered to detect differences in peak expiratory flow rates rather than admission rates. Although retrospective, we feel our study is relevant because it compares two very similar patient populations before and after a significant change in prehospital medical management. The admission rate for those receiving prehospital methylprednisolone was significantly lower (p = 0.025) than those receiving methylprednisolone in the ED (13% vs. 33%). We could identify only one previous study addressing the prehospital use of parenteral corticosteroids.10 Stead et al. retrospectively reviewed EMS runs for asthma patients before and after the addition of protocols, including an intravenous methylprednisolone arm. Adult patients were included in Stead et al.’s study if on retrospective review they were transported by ambulance and had an asthma diagnosis code. Our inclusion criteria were somewhat more restrictive because only patients with a previous diagnosis of asthma were included. We also excluded patients over 50 years old to increase the likelihood that their respiratory disease was asthma. Because the average age in both of our study groups was 34 years, we believe it is unlikely we captured a significant number of patients with chronic obstructive pulmonary dis-
ease. Similar to our protocols, administration of methylprednisolone in Stead et al.’s study was considered only after the patient was treated with betaagonists and continued to have significant symptoms. Unlike our protocols, medical command physicians could also choose an alternate treatment arm that could include magnesium, epinephrine, repeat beta-agonists, or transportation alone. Three patients (27%) of the 11 patients who received prehospital corticosteroid also received prehospital subcutaneous epinephrine. It is difficult to compare our steroid group with Stead et al.’s because the use of alternative prehospital therapies makes the two groups differ significantly. In Stead et al.’s study, no patients in the prehospital corticosteroid group (n = 11) were eventually admitted to the hospital. Our prehospital steroid group had an admission rate of 13% (n = 31). Our higher admission rate could be related to a sicker patient population but more likely reflects the limited power of Stead et al.’s study secondary to the small number of patients. We were surprised to find that our hospital group received corticosteroids on average 40 minutes after arrival by ambulance. Delays in triage, registration, evaluation, intravenous line placement, drug procurement, and administration all likely contribute to this significant delay. If one considers average transport times for Virginia Beach and Norfolk EMS (20 and 10 minutes, respectively (Palmer D and Martin S, personal communication, 2003), without the use of prehospital corticosteroid, delay to drug delivery in the ED would approach one hour. This time difference may account for a significant portion of the benefit of prehospital administration of corticosteroids. No studies to date provide a reasonable comparison of the timing between prehospital corticosteroid administration versus in the ED. As our urban system has generally short transport times, we found drug administration occurred rapidly, on average 15 minutes before arrival to the ED. In more rural prehospital systems not using steroids, delay resulting from transport time and drug administration in the ED is likely amplified. This delay is of concern because disease progression in asthmatic patients can be quite rapid. Implementation of beta-agonists combined with corticosteroids in the prehospital setting would mimic the standard therapy currently received only after arrival to most EDs.
LIMITATIONS Our study does have significant limitations. First, this study was retrospective and not a randomized control trial. Our definition of moderate to severe asthma was based solely on clinical improvement and did not include a peak flow measurement. The decision to administer corticosteroids after the initial albuterol
426
PREHOSPITAL EMERGENCY CARE OCTOBER / DECEMBER 2003
treatment was not standardized for either patient group. Although regional protocols standardized prehospital interventions, physician intervention on arrival to the ED was not standardized in either study arm. Variations in ED therapy could significantly alter admission rates in each group. Decision to admit either group of patients was based on the physician’s judgment and not preset criteria. The relatively small number of patients also limits the power of this study.
CONCLUSION Prospective validation of these results is needed. Even with the limitations of this study and lack of other prehospital data, the early use of corticosteroids in moderate to severe asthma seems warranted based on the existing randomized, controlled trials. The authors thank Harry Poland, PA-C, research advisor, Michael Doviac, PhD, statistics, Frank Councilman, MD, reviewer, City of Norfolk Fire and Paramedical Services, City of Virginia Beach Emergency Medical Services, and Sentara Hospitals for their helpful contributions.
VOLUME 7 / NUMBER 4
References 1. Mannino DN, Homa DM, Pertowski CA, et al. Surveillence for asthma—United States, 1965–1995. MMWR. 1998;47:1-27. 2. National Asthma Education Program. Expert Panel Report II Guidelines for the Diagnosis and Management of Asthma. Bethesda, MD: National Institute of Health, 1997. 3. Beveridge RC, Grunfeld AF, Hodder RV, Verbeek PR. Guidelines for the emergency management of asthma in adults. Can Med Assoc J. 1996;155:25-37. 4. British Thoracic Society. The British guidelines on asthma management: 1995 review and position statement. Thorax. 1995;52:152-6. 5. Lemanske RF Jr, Busse WW. Asthma. JAMA. 1997;278:1855-73. 6. Rowe BH, Spooner C, Ducharme FM, Bretzlaff JA, Bota GW. Early emergency department treatment of acute asthma with systemic corticosteroids (Cochrane Review). In: The Cochrane Library, issue 2. Oxford: Udate Software, 2002. 7. Rowe BH, Keller J, Oxman AD. Steroid use in the emergency department treatment of asthma exacerbations: a meta-analysis. Am J Emerg Med. 1992;10:301-10. 8. Engel T, Heinig JH. Glucocorticoid therapy in acute severe asthma—a critical review. Eur Respir J. 1991;4:1-9. 9. Lin RY, Pesola GR, Bakalchuk L, et al. Rapid improvement of peak flow in asthmatic patients treated with parenteral methylprednisolone in the emergency department: a randomized controlled study. Ann Emerg Med. 1999;33:487-94. 10. Stead L. Evaluation of a new EMS asthma protocol in New York City: a preliminary report. Prehosp Emerg Care. 1999;3:338-42.
ABSTRACT Objective. To compare hospital admission rates for patients with moderate to severe asthma who receive intravenous methylprednisolone given in the prehospital setting versus in the emergency department. Methods. A retrospective chart review was used to identify emergency medical services (EMS) transports of patients with moderate to severe asthma when 125 mg methylprednisolone was given intravenously in the prehospital setting under existing regional protocols. Data were collected on EMS runs in an urban/suburban system from May 1, 2000, through April 30, 2001. Only patients 18 to 50 years old with a history of asthma were included in the study. Patients were excluded if they left against medical advice, were long-term smokers, used home oxygen, or had a history of chronic obstructive pulmonary disease. A parallel search was performed from February 1, 1999, to April 30, 2000, to identify moderate–severe asthmatics who were transported by EMS and later given intravenous methylprednisolone in the emergency department. During this period, methylprednisolone was not available for use in this EMS system. Results. A total of 31 moderate to severe asthmatics were identified as receiving prehospital methylprednisolone. A total of 33 asthmatics were identified who were transported by EMS and later received intravenous methylprednisolone in the emergency department. Average patient age in the prehospital methylprednisolone group was 34 6 10 years (mean 6 standard deviation; 95% confidence interval [CI] = 31–37). Average age in the hospital group was 34 6 10 years (95% CI = 31– 37). Average time to administration of methylprednisolone in
PREHOSPITAL EMERGENCY CARE 2003;7:423–426
Despite advances in the treatment of asthma, mortality has tripled over the last two decades. In 1995, over 5,000 deaths were reported. Annually the disease accounts for over two million emergency department (ED) visits.1 Therapies for treatment are aimed at reversing bronchoconstriction, decreasing secretions, and reducing inflammation. Treatment recommendations from the National Asthma Education Program in the United States,2 the Canadian Association of Emergency Physicians,3 and the British Thoracic Society4 include the use of beta-agonists and systemic corticosteroids. Although the timing and frequency of treatment regimens can be quite variable in the ED, these two medications have become the mainstay of current asthma therapy. Although widely used, the literature addressing the efficacy of early parenteral corticosteriod use in the ED has been somewhat controversial. Prehospital studies on steroid use for acute asthma are, for the most part, nonexistent. It has been argued that because steroids act at the cellular level, their beneficial effects are not clinically evident for hours after administration.5 Even with the potential for delayed clinical effects, it is the
Received November 4, 2002, from the Department of Emergency Medicine (BK), Eastern Virginia Medical School, Norfolk, Virginia; and Emergency Physicians of Tidewater (CW), Virginia Beach, Virginia. Revision received May 24, 2003; accepted for publication May 27, 2003. Address correspondence and reprint requests to: Barry Knapp, MD, Raleigh Building, Room 304, Department of Emergency Medicine, Eastern Virginia Medical School, Norfolk, VA 23507-1999. e-mail:
423
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PREHOSPITAL EMERGENCY CARE OCTOBER / DECEMBER 2003
practice of most clinicians to administer steroids as early as possible in moderate and severe asthma attacks. The most recent evidenced-based review by Rowe et al. supports this practice.6 This Cochrane review concluded that corticosteroid administration within one hour of arriving at the ED significantly reduces hospital admission for patients with an acute exacerbation of asthma. The benefits appeared greatest in patients with more severe asthma and in those not currently receiving steroids. Rowe et al.’s review is consistent with earlier systematic reviews that also support the early use of corticosteroids in the ED.6,7 Even widely accepted ED therapeutic practices are often slow to transition into the prehospital setting. It was not long ago that studies were undertaken to determine if prehospital personnel could safely administer beta-agonists that previously were accessible only on arrival in the ED. There is little doubt that prompt treatment of the asthmatic can often halt disease progression. The prehospital setting provides just such an opportunity for early intervention. We sought to determine if intervention with intravenous corticosteroids in the prehospital setting decreased hospital admission rates for patients with an acute exacerbation of asthma.
METHODS Institutional review board (IRB) consent was obtained for this review. This study was a quasi-experimental historical cohort comparison of asthma patients transported by ambulance to an ED who were experiencing an acute exacerbation of asthma. Before the addition of corticosteroids to our ambulances, standard therapy for asthmatic patients included the serial administration of 2.5 mg albuterol in 3 mL of normal saline via a nebulizer. The use of intravenous methylprednisolone (Solu-Medrol) for moderate to severe asthma was implemented in the Tidewater Emergency Medical System in April 2000. Medics were educated on the indications, dosage, and potential side effects of the medication. Based on current local emergency physician (EP) practice, a parenteral dosage of 125 mg was used. A regional protocol was established to guide its use. According to the protocol, once an asthmatic patient is identified, a nebulized treatment of albuterol is administered. If the patient fails to improve clinically or worsens after the initial albuterol treatment, he or she is considered by the protocol to have a moderate to severe asthma attack. The prehospital care provider then may consider intravenous methylprednisolone. An EP via radio must concur with the paramedic’s assessment and then give the order to administer 125 mg methylprednisolone intravenously. A retrospective chart review was preformed at two Tidewater area EDs from May 1, 2000, through April
VOLUME 7 / NUMBER 4
30, 2001, to identify asthmatic patients who were administered intravenous methylprednisolone in the prehospital setting. Sentara Norfolk General Hospital ED has an annual volume of 53,000 patient visits and functions as a level I trauma center. Sentara Virginia Beach General ED is a level II trauma center with an annual volume of 53,000 patients. A parallel retrospective chart review was done for the year prior to the addition of methylprednisolone to our ambulances to identify those asthmatic patients who were transported via ambulance and later were administered 125 mg methylprednisolone intravenously in the ED. Patients included in the study must have had a previous diagnosis of asthma. Only patients aged 18 to 50 years old were included to increase the likelihood that their primary respiratory disease was asthma. Patients were excluded from the study if they left the ED against medical advice or were admitted to the hospital for reasons other than their asthma. Patients with a greater than 20 pack-year history of smoking or on home oxygen therapy were excluded because of their decreased ability to respond to beta-agonists.2 The statistical package used to analyze the study data was the SPSS Student version 9.0 for Windows (SPSS Inc., Chicago, IL). Fisher’s exact test was used to compare the two groups. Because prior literature overwhelmingly supports the early use of corticosteroid in the treatment of asthma, a one-tailed test was used. Results were considered to be statistically significant if the p-value was less than 0.05.
RESULTS A total of 1,546 asthma patient charts were reviewed. Sixty-four patients met the inclusion criteria. Thirtyone patients had been given methylprednisolone in the prehospital setting and 33 after arrival in the ED. The average age of the patients in the prehospital methylprednisolone group was 34 6 10 years (mean 6 standard deviation; 95% confidence interval CI = 31–37). Average age in the hospital group was 34 6 10 years (95% CI = 31–37). There was no statistically significant difference in the ages of the two groups (p = 0.85). The average time to administration of methylprednisolone in the prehospital setting was 15 6 7 minutes (95% CI = 7–22) with a range of 5 to 30 minutes. The average time elapsed in the ED before methylprednisolone was given was 40 6 22 minutes (95% CI = 23–57) with a range of 15 to 101 minutes. In the prehospital methylprednisolone group, 13% (4) of the patients were eventually admitted to the hospital. Of those who received methylprednisolone in
Knapp and Wood
PREHOSPITAL METHYLPREDNISOLONE
AND
TABLE 1. Patient Disposition
Discharged Admitted
425
HOSPITAL ADMISSION RATE
Prehospital Methylprednisolone
Emergency Department Methylprednisolone
27 4
22 11
the ED, 33% (11) were admitted (p = 0.025). Data are summarized in Table 1.
DISCUSSION This is the only study to date demonstrating that patients with moderate to severe asthma might benefit from the administration of prehospital intravenous corticosteroids. This seems a logical assumption if one concurs with current evidenced-based reviews that advocate the early ED administration of intravenous corticosteroids.6–8 The exact pathophysiological mechanism of rapid clinical improvement is not clearly understood. Lin et al. demonstrated significant rapid improvement in the peak flow of patients who received intravenous methylprednisolone.9 Our patient inclusion criteria were similar to theirs. To identify patients with moderate to severe asthma, only those who failed to improve with an initial dose of albuterol were included in our study. Although peak flow rates improved, Lin et al. were not able to demonstrate a statistical difference in admission rates for intravenous corticosteroids versus placebo. This likely reflects the fact that their study was powered to detect differences in peak expiratory flow rates rather than admission rates. Although retrospective, we feel our study is relevant because it compares two very similar patient populations before and after a significant change in prehospital medical management. The admission rate for those receiving prehospital methylprednisolone was significantly lower (p = 0.025) than those receiving methylprednisolone in the ED (13% vs. 33%). We could identify only one previous study addressing the prehospital use of parenteral corticosteroids.10 Stead et al. retrospectively reviewed EMS runs for asthma patients before and after the addition of protocols, including an intravenous methylprednisolone arm. Adult patients were included in Stead et al.’s study if on retrospective review they were transported by ambulance and had an asthma diagnosis code. Our inclusion criteria were somewhat more restrictive because only patients with a previous diagnosis of asthma were included. We also excluded patients over 50 years old to increase the likelihood that their respiratory disease was asthma. Because the average age in both of our study groups was 34 years, we believe it is unlikely we captured a significant number of patients with chronic obstructive pulmonary dis-
ease. Similar to our protocols, administration of methylprednisolone in Stead et al.’s study was considered only after the patient was treated with betaagonists and continued to have significant symptoms. Unlike our protocols, medical command physicians could also choose an alternate treatment arm that could include magnesium, epinephrine, repeat beta-agonists, or transportation alone. Three patients (27%) of the 11 patients who received prehospital corticosteroid also received prehospital subcutaneous epinephrine. It is difficult to compare our steroid group with Stead et al.’s because the use of alternative prehospital therapies makes the two groups differ significantly. In Stead et al.’s study, no patients in the prehospital corticosteroid group (n = 11) were eventually admitted to the hospital. Our prehospital steroid group had an admission rate of 13% (n = 31). Our higher admission rate could be related to a sicker patient population but more likely reflects the limited power of Stead et al.’s study secondary to the small number of patients. We were surprised to find that our hospital group received corticosteroids on average 40 minutes after arrival by ambulance. Delays in triage, registration, evaluation, intravenous line placement, drug procurement, and administration all likely contribute to this significant delay. If one considers average transport times for Virginia Beach and Norfolk EMS (20 and 10 minutes, respectively (Palmer D and Martin S, personal communication, 2003), without the use of prehospital corticosteroid, delay to drug delivery in the ED would approach one hour. This time difference may account for a significant portion of the benefit of prehospital administration of corticosteroids. No studies to date provide a reasonable comparison of the timing between prehospital corticosteroid administration versus in the ED. As our urban system has generally short transport times, we found drug administration occurred rapidly, on average 15 minutes before arrival to the ED. In more rural prehospital systems not using steroids, delay resulting from transport time and drug administration in the ED is likely amplified. This delay is of concern because disease progression in asthmatic patients can be quite rapid. Implementation of beta-agonists combined with corticosteroids in the prehospital setting would mimic the standard therapy currently received only after arrival to most EDs.
LIMITATIONS Our study does have significant limitations. First, this study was retrospective and not a randomized control trial. Our definition of moderate to severe asthma was based solely on clinical improvement and did not include a peak flow measurement. The decision to administer corticosteroids after the initial albuterol
426
PREHOSPITAL EMERGENCY CARE OCTOBER / DECEMBER 2003
treatment was not standardized for either patient group. Although regional protocols standardized prehospital interventions, physician intervention on arrival to the ED was not standardized in either study arm. Variations in ED therapy could significantly alter admission rates in each group. Decision to admit either group of patients was based on the physician’s judgment and not preset criteria. The relatively small number of patients also limits the power of this study.
CONCLUSION Prospective validation of these results is needed. Even with the limitations of this study and lack of other prehospital data, the early use of corticosteroids in moderate to severe asthma seems warranted based on the existing randomized, controlled trials. The authors thank Harry Poland, PA-C, research advisor, Michael Doviac, PhD, statistics, Frank Councilman, MD, reviewer, City of Norfolk Fire and Paramedical Services, City of Virginia Beach Emergency Medical Services, and Sentara Hospitals for their helpful contributions.
VOLUME 7 / NUMBER 4
References 1. Mannino DN, Homa DM, Pertowski CA, et al. Surveillence for asthma—United States, 1965–1995. MMWR. 1998;47:1-27. 2. National Asthma Education Program. Expert Panel Report II Guidelines for the Diagnosis and Management of Asthma. Bethesda, MD: National Institute of Health, 1997. 3. Beveridge RC, Grunfeld AF, Hodder RV, Verbeek PR. Guidelines for the emergency management of asthma in adults. Can Med Assoc J. 1996;155:25-37. 4. British Thoracic Society. The British guidelines on asthma management: 1995 review and position statement. Thorax. 1995;52:152-6. 5. Lemanske RF Jr, Busse WW. Asthma. JAMA. 1997;278:1855-73. 6. Rowe BH, Spooner C, Ducharme FM, Bretzlaff JA, Bota GW. Early emergency department treatment of acute asthma with systemic corticosteroids (Cochrane Review). In: The Cochrane Library, issue 2. Oxford: Udate Software, 2002. 7. Rowe BH, Keller J, Oxman AD. Steroid use in the emergency department treatment of asthma exacerbations: a meta-analysis. Am J Emerg Med. 1992;10:301-10. 8. Engel T, Heinig JH. Glucocorticoid therapy in acute severe asthma—a critical review. Eur Respir J. 1991;4:1-9. 9. Lin RY, Pesola GR, Bakalchuk L, et al. Rapid improvement of peak flow in asthmatic patients treated with parenteral methylprednisolone in the emergency department: a randomized controlled study. Ann Emerg Med. 1999;33:487-94. 10. Stead L. Evaluation of a new EMS asthma protocol in New York City: a preliminary report. Prehosp Emerg Care. 1999;3:338-42.