Discharge considerations for adult asthmatic patients treated in emergency departments

OB JEC TIVE: To re view the medi cal lit era ture on out come of treat ment of acute asthma in the emer gency de part ment and is sue rec om men da tions re gard ing pa tient ad mis sion or dis charge. DATA SOURCES: A MED LINE search was done for ar ti cles in the Eng lish lan guage on acute asthma and treat ment in the emer gency de part ment for the years 1975 to 1993. In ad di tion, ref er ences in per ti nent re view ar ti cles were re viewed. STUDY SE LEC TION: Stud ies ad dress ing treat ment of acute asthma in emer gency de part ments were se lected by con sen sus. DATA SYN THE SIS: Three ma jor ar eas have been shown to af fect out come and the de ci sion to ad mit or dis charge a pa tient fol low ing treat ment in the emer gency de part ment: first, the se ver ity of the at tack and the re sponse to ther apy; sec ond, his tori cal risk fac tors; and third, care fol low ing dis charge from the emer gency de part ment. This pa per re views the lit era ture on out come of acute asthma at tacks and is sues rec om men da tions re gard ing ob jec tive air flow meas ure ments and coexisting risk fac tors to be as sessed be fore dis charg ing pa tients. The role of antiinflammatory ther apy in emer gency de part ment treat ment and in post dis charge treat ment of these pa tients is also re viewed. CON CLU SION: Evalua tion for dis charge fol low ing treat ment of acute asthma should in te grate ob jec tive meas ures of air flow ob struc tion with his tori cal high risk fac tors. The use of sys temic cor ti cos ter oids in the emer gency de part ment and fol low ing dis charge, with care ful followup, may help con trol the at tack and re duce re lapse of asthma.


Ques tions rela tives au congé des adul tes asthma tiques trai tés aux serv ices des ur gences
OB JEC TIF : Revoir la litté ra ture médi cale sur les résul tats du traite ment de l'asthme aigu au serv ice des ur gences et émet tre des re com man da tions quant à l'hos pi tali sa tion ou la nonhospitalisation des pa tients.SOURCES DES DONNÉES : Dans MED LINE, on a re cher ché les ar ti cles de langue anglaise por tant sur l'asthme aigu et son traite ment au serv ice des ur gences, de 1975 à 1993.De plus, on a passé en re vue les réfé rences dans les ar ti cles de syn thèse per ti nents.SÉ LEC TION DES ÉTUDES : Les études trai tant du traite ment de l'asthme aigu aux serv ices des ur gences ont été sé lec tionnées par con sen sus.SYN THÈSE DES DONNÉES : On a démon tré que trois fac teurs prin ci paux af fec taient les résul tats de la dé ci sion vi sant à hos pi taliser ou à don ner congé à un pa tient suite à un traite ment au serv ice des ur gences.En pre mier, la gravité de la crise d'asthme et la réponse au traite ment; en sec ond, les anté cédents de fac teurs de Correspondence: Dr Anton Grunfeld, Department of Emergency Medicine, Vancouver Hospital and Health Sciences Centre, 855 West 12th Avenue, Vancouver, British Columbia V5Z 1M9.Telephone 604-875-4995, fax 604-875-4872, e-mail grunfeld@unixg.ubc.cavoir page suivante A l though the great ma jor ity of pa tients treated in emer - gency de part ments (ED) with acute asthma re cover and are safely dis charged home, sig nifi cant mor bid ity and mortal ity are well-recognized (1)(2)(3).The im por tant out comes to be pre vented are death or a near fa tal event, and re lapse with a fur ther epi sode of acute asthma.Be cause most asthma deaths oc cur in the com mu nity and those deaths that oc cur in the ED are usu ally in pa tients who ar rive mori bund (2), this ar ti cle fo cuses on the ED evalua tion of pa tients in whom a de ci sion re gard ing ad mis sion or dis charge needs to be made.In ad di tion, it will re view the im por tant role of antiinflammatory ther apy in the follow-up care of these pa tients.

DISCHARGE CONSIDERATIONS
Be cause of the com plex ity of medi cal and non medi cal fac tors as so ci ated with the out come of an asth matic at tack (4), our abil ity to pre dict and al ter it is im per fect.The three ma jor ar eas that have been shown to af fect out come and thus re quire evalua tion be fore dis charg ing the pa tient are as follows: • the se ver ity of the at tack and re sponse to ther apy; • his tori cal high risk fac tors; • care fol low ing dis charge.

SEVERITY OF THE ATTACK AND RESPONSE TO THERAPY
The as sess ment of the se ver ity of an acute asthma at tack is based both on clini cal ex ami na tion and on the ob jec tive evalua tion of air flow ob struc tion.Sev eral physi cal signs have been rec og nized as be ing as so ci ated with lifethreatening asthma, such as tachy car dia, tachyp nea, use of ac ces sory mus cles, pul sus para doxus, dia pho re sis and an inabil ity to com plete sen tences in one breath.More omi nous signs in clude a si lent chest, cya no sis, bra dy car dia and decreased lev els of con scious ness.It must be noted that the ab -sence of these signs can not be in ter preted as sig ni fy ing that the at tack is not life-threatening.In ad di tion, stud ies in both adults and chil dren failed to show a good cor re la tion be tween the physi cal find ings and physio logi cal meas ure ments in the as sess ment of acute air way ob struc tion (5-7), un der lin ing the need for us ing ob jec tive air flow meas ure ments in ad di tion to the clini cal ex ami na tion.
At tempts have been made to con struct and vali date se verity scores for acute asthma to pre dict the need for hos pi tali zation and safety in dis charg ing pa tients.Fischl et al (8) de vel oped an in dex score based on heart rate over 120 beats/min, res pi ra tory rate more than 30 breaths/min, pul sus para doxus 18 mmHg or greater, peak ex pi ra tory flow rate (PEFR) 120 L/min, mod er ate to se vere dysp nea, the use of ac ces sory mus cles and wheez ing.Each of the signs was scored with one point.The authors found that a score of 4 or more was 96% ac cu rate in pre dict ing the need for hos pi taliza tion and 95% ac cu rate in pre dict ing re lapse.How ever, when this scale was tested pro spec tively in two other lo cations, it failed to show any use ful pre dic tive value (4,9).
Sev eral authors have cor re lated the se ver ity of air way obstruc tion on pres en ta tion and at dis charge from the ED with the prob abil ity that the pa tient would suf fer a re lapse.In a pro spec tive study, Kel sen et al (7) found no sig nifi cant differ ence in the ini tial level of air flow ob struc tion be tween patients who did and those who did not ex pe ri ence re lapse within the next 10 days (mean forced ex pi ra tory vol ume in 1 s [FEV 1 ] was 1.15 L for the group as a whole, P>0.05).How ever, pa tients with sig nifi cantly lower lev els of lung func tion and a smaller de gree of im prove ment in lung function at the time of dis charge were shown to be more likely to suf fer a sub se quent re lapse (Ta ble 1).Pa tients who showed an FEV 1 in crease af ter treat ment of 400 mL had a 67% relapse rate, while those with an im prove ment of more than 400 mL had a re lapse rate of only 29%.
Ban ner and co-workers (10), in a pro spec tive evalua tion of 67 epi sodes of acute asthma, found that pa tients who were suc cess fully dis charged had a me dian peak flow of 70% predicted.In the seven epi sodes where the treat ment failed, no pa tients had peak flow greater than 42% pre dicted.In ad dition, pa tients with ini tial peak flows of less than 16% predicted and less than 16% im prove ment af ter an ini tial in jec tion of adrena line were ad mit ted or had a re lapse (Table 2).Fischl et al (8), in a pro spec tive evalua tion of 205 pa tients with acute asthma, found that PEFR at pres en ta tion was signifi cantly higher in pa tients who were suc cess fully discharged than in those who were ad mit ted or re lapsed (157 L/min ver sus 94 L/min and 89 L/min, re spec tively).At dispo si tion, PEFRs in suc cess fully dis charged pa tients were sig nifi cantly bet ter than those in pa tients who ex pe ri enced a re lapse, which were bet ter than those in ad mit ted pa tients (299 L/min, ver sus 191 L/min, ver sus 118 L/min, re spectively) (Ta ble 3).
Nowak et al (11), in a pro spec tive evalua tion of 85 episodes of acute asthma, also found sig nifi cant dif fer ences in FEV 1 among the three groups of pa tients, both at the time of pres en ta tion and fol low ing treat ment (Ta ble 1).Thirty-five per cent of the pa tients stud ied had an ini tial FEV 1 of 0.6 L or less and a post-treatment FEV 1 of 1.6 L or less.Ninety per cent of pa tients ei ther were ad mit ted or had a sub se quent relapse.
In two fur ther stud ies, Nowak et al (12,13) also found signifi cant dif fer ences among val ues of air flow in ad mit ted patients, pa tients who de vel oped prob lems fol low ing dis charge and pa tients who were dis charged with out re lapse (Ta bles 1-3).In one of these stud ies (12), 92% of pa tients with a pretreat ment PEFR of less than 100 L/min and a post-treatment value of less than 300 L/min re quired ad mis sion or had an un suc cess ful out-patient course.Of pa tients with a pre treatment PEFR of less than 100 L/min and an im prove ment of less than 60 L/min af ter ini tial ter bu ta line, 85% were ad mitted or had prob lems af ter dis charge.
Fanta et al (14), in a pro spec tive evalua tion of dif fer ent thera peu tic com bi na tions, found that the rate and mag ni tude of re sponse in the first hour de pended on the se ver ity of airway ob struc tion at pres en ta tion.In this study it was found that pa tients with an ini tial FEV 1 of less than 30% pre dicted and who did not im prove to an FEV 1 of at least 40% predicted at the end of 60 mins of in tense bron cho di la tor ther apy re quired pro longed ED treat ment and/or hos pi tal ad mis sion.
The data in these stud ies show con sis tency in cor re lat ing spi ro met ric meas ure ments and out come.This al lows for recom men da tions re gard ing dis charge of asth matic pa tients from the ED, as sum ma rized in Ta ble 4. The ab so lute val ues    given are ap proxi ma tions for the 'a ve rage adult'.Per cent age pre dicted or pre vi ous best are more help ful when avail able.
The pre-and post-treatment FEV 1 or PEFR are proba bly the best guides to ther apy.How ever, there are two points worth not ing: first, cor ti cos ter oids were not rou tinely used as part of the pro to col in these stud ies; and sec ond, the dis charge cri te ria sug gested in these stud ies, based on air flow ob struc tion, have not been pro spec tively vali dated.
Sev eral authors have showed that re li ance on FEV 1 or PEFR as the only cri te rion to pre dict the need for hos pi tali zation or re lapse has limi ta tions.Ver beek and Chap man (15) ex am ined Nowak's data and showed that us ing a pro posed PEFR above 300 L/min or an FEV 1 greater than 2.1 L would lead to one-third of all rec om mended ad mis sions be ing unnec es sary.Wor thing ton and Ahuja (16) found that us ing the com bi na tion of FEV 1 of at least 0.7 L at pres en ta tion and FEV 1 of at least 2.1 L be fore dis charge had a low posi tive pre dic tive value (47%) for ad mis sion or re lapse.How ever, a fi nal FEV 1 of greater than 2.4 L had a high sen si tiv ity (90%) and nega tive pre dic tive value (94%) when used as a cri te ria for dis charge.Pa tients who at tained this value could be discharged with a high de gree of con fi dence.While in di cat ing a safe dis charge, this cut-off value was not use ful for de cid ing ad mis sion be cause of the low speci fic ity of only 41%.In this study, knowl edge of the FEV 1 did not al ter the de ci sion to admit or dis charge a pa tient in 97% of cases.
In spite of the above limi ta tions, be cause of the known varia tions in the abil ity of pa tients to es ti mate the se ver ity of air flow ob struc tion (17)(18)(19)(20) the meas ure ments are im por tant, not only in gaug ing ob jec tively the re sponse to ther apy, but also in in te grat ing these lev els into de ci sions re gard ing dispo si tion, as out lined above.

HISTORICAL HIGH RISK FACTORS
Stud ies of asthma deaths have iden ti fied his tori cal fac tors that in crease the risk of pa tients dy ing of their dis ease.These in clude a re cent hos pi tal ad mis sion, a re cent visit to the ED, poor medi cal man age ment and poor com pli ance (21)(22)(23)(24)(25)(26)(27)(28).
In a ret ro spec tive case con trol study of death from asthma, Rea et al (29) con firmed the sig nifi cance of these risk fac tors.In ad di tion, they showed that psy cho logi cal prob lems were more com mon in cases than in con trols.These in cluded recent un em ploy ment, re cent be reave ment, de pres sion, person al ity dis or ders and al co hol abuse.They con cluded that the best way to iden tify asthma pa tients at risk of death is to identify those who have had a re cent hos pi tal ad mis sion and, in par ticu lar, those who have ever had a life-threatening at tack re quir ing me chani cal ven ti la tion.
The ex is tence of two groups of pa tients who are con sidered at risk of dy ing from asthma was noted at a re cent consen sus meet ing on asthma mor tal ity (30).The groups are: • pa tients with a his tory of near fa tal epi sodes, re quir ing re sus ci ta tion, re gard less of the un der ly ing se ver ity of disease or pres ence of any other risk fac tors • pa tients with un der ly ing se vere dis ease, judged by chronic se vere symp toms, sys temic ster oid re quire ment, fre quent regu lar use of bron cho di la tors, fre quent ED visits or hos pi tali za tions.Pa tients in this group may also have one or more of the fol low ing prob lems: re cent dis charge from the hos pi tal for se vere asthma, poor self-care or noncom pli ance with medi ca tions, de pres sion or se vere emotional dis tur bance, sig nifi cant other psy cho logi cal fac tors, or short com ings in edu ca tion and su per vi sion.
The po ten tial role of in dis crimi nate use of beta-agonists as a risk fac tor for fa tal asthma has re ceived at ten tion re cently.A number of case con trol stud ies from New Zea land have sug gested that the use of fe noterol may be as so ci ated with an in creased risk of death from asthma (31,32).More re cently, Spit zer et al (33) matched 129 cases who had fa tal or near fatal asthma and com pared them with 655 con trols from the Sas katche wan Health In sur ance da ta base.The use of both fenoterol and al buterol was as so ci ated with in creased risk of death (OR 2.6 per can is ter per month, CI 1.7 to 3.9) and of death or near death from asthma con sid ered to gether (OR 1.9 per can is ter per month).The ad verse ef fect of regu lar use of beta-agonist was also shown by Sears et al (34) in a cross over study that com pared on-demand ver sus regu lar use of fenoterol.The regu lar use of fe noterol was as so ci ated with less op ti mal asthma con trol than its use on de mand.
Molfino et al (35) ex am ined the char ac ter is tics of 10 patients who ar rived at hos pi tal in res pi ra tory ar rest or in whom it de vel oped within 20 mins of ar ri val at the ED.These patients were simi lar to those de scribed in the lit era ture with a high risk of death from asthma, in clud ing a long his tory of asthma in young-to middle-aged pa tients, pre vi ous lifethreatening at tacks or hos pi tali za tion, de lay in medi cal aid and sud den on set of a rap idly pro gres sive at tack.Ex treme hyper capnia and aci do sis were found be fore me chani cal venti la tion was be gun, but no pa tient de vel oped se ri ous car diac ar rhyth mias dur ing re sus ci ta tion.They sug gest that un dertreat ment, as shown by se vere as phyxia, rather than overtreat ment with po ten tial car dio tox ic ity, may be a ma jor fac tor in the in creased number of deaths from asthma.
Kal len bach et al (36) stud ied 81 pa tients with acute se vere asthma in whom me chani cal ven ti la tion was re quired.In this group of pa tients they found no evi dence to sup port the con -cept of car dio tox ic ity re lated to bron cho di la tors con trib ut ing sig nifi cantly to mor tal ity from asthma.On the con trary, there ap peared to have been se ri ous un der treat ment in many cases, par ticu larly as re gards cor ti cos ter oids.The in ves ti ga tors iden ti fied a group of pa tients with 'h ype racute' asthma in whom the du ra tion of the at tack from on set to me chani cal ven ti la tion was less than 3 h.This group was as so ci ated with an in creased risk of near fa tal epi sodes (P<0.03), and hy peracute at tacks were uni formly near fa tal.
The data in these stud ies show con sis tency and al low for rec om men da tions re gard ing the con sid era tion of his tori cal risk fac tors be fore dis charge of asth matic pa tients from the ED.Pa tients with the char ac ter is tics listed in Ta ble 5 are at risk of re lapse.How ever, it is worth not ing that these high risk cri te ria have not been vali dated in pro spec tive stud ies.

FOLLOW-UP CARE
In re cent years the piv otal role that air way in flam ma tion plays in the patho gene sis of asthma has been rec og nized (37).Jef frey et al (37), in an ul tra struc tural study of bi op sies taken from the air ways of pa tients with asthma and com pared with con trol sub jects, showed the pres ence of in flam ma tory changes in the pa tients with asthma that were not found in the con trols.They in par ticu lar found an in crease in lym pho cytes in the air way and pos tu lated that these cells play a promi nent role in the in flam ma tory pro cess.It fol lows that pa tients present ing to the ED have a sig nifi cant amount of air way mu cosal in flam ma tion and edema.These air way changes have been the ba sis for the many rec om men da tions to use antiinflammatory ther apy, usu ally in the form of sys temic cor ticos ter oids (38).De spite this ra tion ale pa tients con tinue to be dis charged from the ED with out such ther apy (39), lead ing to un ac cepta bly high rates of re lapse as well as on go ing poor symp tom con trol.
A re cent meta-analysis (40), as well as a pre limi nary report of our own (41), criti cally re viewed the cur rent lit era ture and made spe cific rec om men da tions as to dos age and route of ad mini stra tion of cor ti cos ter oids in acute asthma.Rowe and Ox man (40) re viewed over 700 ar ti cles and found 30 rele vant ran dom ized con trolled tri als.They found that early use of cor ti cos ter oids for ex ac er ba tions re duced hos pi tal admis sions for adults (OR 0.47, 95% CI 0.27 to 0.79) and children (OR 0.06 to 0.42).In the out-patient set ting they also found that cor ti cos ter oids pre vented re lapses in pa tients with acute ex ac er ba tions (OR 0.15, 95% CI 0.05 to 0.44).The major ity of pa tients who come to the ED with acute asthma have dis ease of such se ver ity that sys temic cor ti cos ter oids are re -quired.Largely based on one study the dose of cor ti co s teroids given has usu ally been 125 mg of meth yl predni so lone in tra ve nously (42).How ever, a number of stud ies have shown that oral predni sone will suf fice, even in sub jects requir ing hos pi tal ad mis sion (43,44).Rowe also looked at the ef fect size of oral ver sus in tra ve nous cor ti cos ter oids and found no dif fer ence in the groups treated with ei ther route.
Tra di tion ally a dose of predni sone 40 mg has been rec ommended for sub jects dis charged from the ED (45).Where this dose is used, and in the pres ence of the on go ing use of inhaled anti-inflammatory ster oids, rou tine ta per ing of cor ti cos ter oids at the end of a 10-day course of sys temic medi ca tion is not re quired (46).O'Dris coll et al (46) evalu ated 35 patients ad mit ted to hos pi tal with an acute ex ac er ba tion of asthma, ran dom ized them to a 10-day course of predni so lone 40 mg daily and then ran dom ized them to pla cebo or a tra ditional ta per ing dose and found no dif fer ence be tween the two groups.The im por tance of main te nance anti-inflammatory in haled cor ti cos ter oids can be gauged from the fact that, although there was a treat ment ef fect at the end of 10 days in the study of Chap man et al (45), there was no such dif fer ence at 21 days, show ing that short term bene fit of sys temic cor ticos ter oids is rap idly lost in the ab sence of ap pro pri ate on going care.
Al though the use of a dou bling dose of in haled cor ti co ster oids has been rec om mended in a number of asthma guidelines (47), there are no pub lished data sup port ing this rec ommen da tion in pre vent ing the evo lu tion of de te rio rat ing asthma into a full-blown acute at tack.Al though in tui tively it makes sense, the dos ing and du ra tion of such ther apy needs to be vali dated in a pro spec tive study.
Pa tients are usu ally re ferred to fam ily phy si cians for follow-up within the fol low ing week to moni tor re sponse to ther apy.There is evi dence, how ever, that fa cili tated re fer ral to a spe cial ist leads to im prove ment in on go ing asthma care (48) and likely leads to a bet ter tran si tion from acute care to ap pro pri ate on go ing con trol of the un der ly ing asthma.The in te gra tion of a pro gram of asthma edu ca tion and these therapeu tic in ter ven tions will likely lead to bet ter re sults (49,50).These stud ies sup port the rec om men da tions listed in Ta ble 6.

CONCLUSIONS
Pa tients pre sent ing to the ED should have air flow ob struction evalu ated ob jec tively.These meas ure ments should be in te grated with his tori cal fea tures out lined above in com ing to a de ci sion on ad mis sion or dis charge.The use of sys temic cor ti cos ter oids and follow-up with topi cal in haled cor ti co ster oids will en sure good ini tial and on go ing con trol of asthma and pre vent many ad mis sions to hos pi tal, re duce relapse rate and, over time, lead to lower asthma mor bid ity and likely mor tal ity.

AC KNOW LEDGE MENTS:
This pa per was pre pared in con junction with the de vel op ment of Guide lines for Emer gency Man agement of Adult Asthma by the Asthma Work Group of the Ca na dian As so cia tion of Emer gency Phy si cians.The authors also thank Drs Naser Awadh and Ken dall Ho for their re view of the manu script.Recommendations for follow-up care Majority of patients require systemic corticosteroids in the emergency department and following discharge Patients need to be educated in the use of their medication and recognition and treatment of relapse Follow-up by the family doctor or a specialist, especially in high risk cases, is required

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326 Can Respir J Vol 3
No 5 Sep tem ber/Oc to ber 1996 Grun feld and FitzGer ald TABLE 6

323 Dis charge con sid era tions in acute asthma risque
, et en troisième, les soins que le pa tient re cevra à sa sor tie du serv ice des ur gences.Le pré sent ar ti cle passe en re vue la litté ra ture sur l'a boutisse ment des cri ses d'asthme ai guës et émet des re comman da tions à pro pos de la me sure ob jec tive du dé bit aé rien et des fac teurs de risque con comi tants qui doivent être évalués avant de don ner congé aux pa tients.Le rôle d'une thé ra pie antiinflammatoire ad min is trée à ces pa tients au serv ice des ur gences, et suite à leur congé, est aussi ex aminé.
Can Respir J Vol 3 No 5 Sep tem ber/Oc to ber 1996