- Email: [email protected]
Prevention of Fatal Asthma
Prevention of Fatal Asthma* Patrick Barriot, M.D.; and Bruno Riou, M.D.
Over a 31-month period, 980 calls from asthmatic patients were received at the switchboard office of a prehospital emergency care unit. A total of 90 patients (9 percent) died before receiving any medical help, and 216 (22 percent) patients were taken to the hospital with an emergency care ambulance where none of them died. We made the assumption that, when an asthmatic patient calls an emergency care unit, the attack is severe and might be fatal. A prospecti.e study was performed during a six-month period to prevent these asthma deaths: 259 calls from asthmatic patienb were received. For each emergency call from asth-
matic patients, paramedical help (delay: 5.1:1:0.3 minutes) and an emergency care ambulance (delay: 9.7:1:0.6 minutes) were immediately sent, Only four patients died during this period, Emergency calls from asthmatic patients must be considered as related to a severe attack that might be fatal. Fatal asthma is often related to a severe attaCk that evolves rapidl~ Some asthmatic patients are able to assess the ·severity of asthma attacks, and prehospital emergency care schemes for asthmatic patients are actually able to prevent some asthma deaths.
phYSicianS are concerned that mortality from asthma fails to decline despite modern treatment. 1 The literatureU provided some preliminary conclusions about asthma deaths as follows: (1) most of the asthmatic patients died at home or during transportation to the hospital; (2)the severity ofthe attack was difficult to assess by the asthmatic patient, his relatives, and his medical practitioner; (3)delays in the arrival of medical aid or in reaching a hospital were shown to be deleterious; (4) most asthmatic deaths could be prevented since avoidable factors were identified in the events that led to more than 80 percent ofdeaths." and (5)very rapid progress of some severe attacks could have contributed to the mortality, and these sudden deaths are difficult to prevent. Crompton et al6•7 developed an emergency asthma service using self-referral to hospital for asthmatic patients and found a lower mortality rate among patients with access to this service than that among patients with access to other asthma services in the same area. Nevertheless, some authors" found that, despite a great increase in hospital admissions, no reduction in mortality rate was observed using a similar scheme in children. It is likely that selfadmission services are solely useful in cooperative patients. A controlled evaluation of the effects of two educational programs on asthma morbidity was recently reported by Hilton et al." These authors demonstrated that these programs were ineffective when applied to a general practice population, especially considering the
incidence of severe attacks. This study suggested that development of educational programs is probably not the only way to reduce asthma mortality. The aim of this study was to decrease the incidence of fatal asthma with improvement in prehospital management of emergency calls from asthmatic patients. This study was based on an assumption: asthmatic patients who call an emergency care unit actually have a severe attack that might be fatal. Thus, a standardized behavior was decided, whatever the apparent severity of the asthma attack.
-From the Service de Sante de la Brigade des Sapeurs Pompiers de Paris, and the Departement d'Anesthesle-Reanimation, Groupe Hospitalier Piti6-S81petriere, Universlte de Paris, France. Manuscript received October 9; revision accepted February 26. Reprint requeat8: Dr. Barriot, BSPp, 47 Rue Saint-Fargeau, 75020 Ibm, France
480
METHODS
The study involved two parts. A retrospective study was performed to analyze data from asthma deaths in our unit and to enable comparison with the prospective part of the study. Moreover, in order to confirm or show up the weakness of our assumption that patients who called our unit actually had a severe attack of asthma, peak-flow was systematically measured in asthmatic patients who called our unit.
Description of the Prehospital Emergency Care Unit The unit depends on the Fire Brigade of Paris. Emergency calls are received at a switchboard office where a chief physicJan makes an appropriate decision as fOllows: (1)gives advice to die patients or his relatives; (2) sends firemen trained in external cardiac massage and ventilation with oxygen and a face mask (paramedical aid); (3) sends an emergency care ambulance with a physician. Firemen or the physician inform the chiefphysician by either radio or phone, about the patients clinical status, and an appropriate decision is made concerning the opportunity of hospital admission with an emergency care ambulance. For each patient transported to the hospital with an emergency care ambulance, a standardized data sheet is completed by the physician, giving some details about the history of the patient, clinical findings, and treatment given during the transport to the hospital. Firemen are based in 78 different sites in Paris and its environs, and can reach any patient within ten minutes after the emergency call. Six emergency care ambulances are based in five different sites and can reach any patient within 30 minutes. The phone of the unit is the one of all Fire Brigades (number 18) throughout the country, is written on all telephone sets, and is known by everybody. PnMnion of Fetal Asthma (8tIrtk1, RJou)
Our unit receives emergency calls from a well-defined area of Paris and its environs. The population of this area was evaluated using data obtained during the 1982 census of the "Institut National de la Statistique et des Etudes Economiques.P'
Definition An asthmatic patient's call was defined as an emergency call concerning a patient who experienced a dyspneic attack and during which the word cc asthma" was pronounced, whoever the person who called (the patient himself a relative, or a general practitioner). Near-fatal asthma was defined as an attack of asthma in a patient successfully resuscitated from cardiac or respiratory arrest in two situations as follows: (1) arrest supervened before the physician's arrival, or (2) arrest supervened after the physician's arrival and before reaching the hospital, but unexpected according to the initial clinical status assessed by the physician.
Retrospective Study The retrospective study was performed from January 1983 to August 1985. The number of emergency calls from asthmatic patients received at the switchboard office of our unit was recorded every month, as well as the number of patients who were judged critically ill, and thus, taken to the hospital using an emergency care ambulance. The number of patients who called, and the number of patients taken to the hospital during this period were also recorded to compare the activity of our unit during the retrospective and the prospective parts of the study. As a matter of fact, precise data from asthmatic patients who called and were not taken to the hospital with an emergency care ambulance, were not available. All deaths related to asthma from January 1983 to August 1985 were studied. The criteria for inclusion were as follow: (1) a convincing clinical history of asthma, ie, evidence of Significant reversibility of airway obstruction as shown by objective measurement or prompt response to treatment with bronchodilators; (2) a first episode of airway obstruction before age 50. An agreement of the two co-ordinators who independently examined the data-sheet was necessary for inclusion. In including our patients, we were aware of the difficulties of interpreting "a clinical convincing history of asthma." There must be reservations about the accuracy of making a diagnosis of asthma in some patients as in any retrospective study dealing with fatal asthma. For asthma to be accepted as a cause of death, the two co-ordinators' opinion had to be identical. Attention was particularly focused on associated diseases to determine whether the patient died of asthma: patients with chronic obstructive pulmonary disease, emphysema, and heart disease were excluded. Patients were considered to have either a rapid (:51 hour) or a prolonged (>1 hour) attack of asthma.
Prospective Study The prospective study was performed from September 1985 to February 1986. It was decided that, when an asthmatic patient called, both a fire team and an ambulance with a physician, were immediately sent to him and the patient was taken to the hospital, whatever the apparent severity of the asthma attack. Information about this study was given to all the physicians of our unit, chiefs of each team offiremen, and to the whole staff of the switchboard office. No information was given to any media or to general practitioners during this study, and none of our physicians was in charge of asthmatic patients outside our unit. A simple questionnaire was completed at the switchboard office for each emergency call from asthmatic patients, and the usual standardized data-sheet was completed by the physician. A questionnaire was completed by one of us, giving details on the asthmatic illness and the circumstances of the asthma attack, by interviewing the patients who experienced near-fatal asthma. Interviews were performed at home, after the patients had been discharged from the hospital. The follow-up status (dead or alive, occurrence of any emergency admission to an hospital
during trial time or not) was determined by telephone call to all surviving patients every month, until August 15 to 20, 1986 (closing date), and the trial time of each patient was recorded. The trial time was defined as the time to the last telephone call after the near-fatal attack of asthma. During the prospective study, peak-flow was systematically measured in the last 101 consecutive asthmatic patients who called our emergency care unit and did not experience near-fatal asthma. The peak-flow value for each patient was the best of three measurements.
Statistical Analysis The distribution of the number of asthma deaths per month during the retrospective study was fitted to a Poisson distribution using a X2 test as previously described by Steel and Torrie. U According to a Poisson distribution, the probability of observing k deaths in a month is given by: P(k) = e-"'· JAok • kl- 1, IJ. being the average number of deaths per month. The probability of the mortality rate observed during the prospective study was calculated using this Poisson distribution. Comparison between the two periods of the study was performed using two-tailed Student's t-test for unpaired data and Fishers exact method or X2 test whenever appropriate. A p value <0.05 was necessary to reject a null hypothesis. Data were expressed as mean ± standard error on the mean (m ± SE M). RESULTS
Retrospective Study Some 980 emergency calls from asthmatic patients were recorded during the study period. A total of 216 (22 percent) of these patients were taken to the hospital with an emergency care ambulance and none of them died. Ninety (9.2 percent) asthmatic patients who called died; 36 asthmatic deaths occurred in 1983; 31 in 1984; and 23 from January to August 1985. A total of 21 (23 percent) patients were found in respiratory or cardiorespiratory arrest by their relatives or a practitioner. Death of the remaining 69 (77 percent) patients was considered as rapid in 47 (52 percent) patients or prolonged episode of respiratory distress in 22 (24 percent) patients; in these 69 (77 percent) patients, death occurred before any medical aid or during the transportation to the hospital in a common ambulance or in a private cal: A total of 66 patients (73 percent) surely used l3-mimetic inhaler before our arrival, and ten patients (11 percent) probably used l3-mimetic inhaler: No other drug was taken by the remaining 23 patients (26 percent) before our arrival. The number of deaths per month was shown to be correctly predicted by a Poisson distribution (JL = 2.75 death/month) as shown in Figure 1. During this period, no asthmatic patient who experienced cardiorespiratory arrest or respiratory arrest before arrival of the physician, was successfully resuscitated. The population which depended on our unit was estimated to be 3,584,398 persons. Since the mean number of asthma deaths per year was 34 during the retrospective study, the lower limit of the incidence of asthma deaths in Paris was 1.05/100,000 persons. CHEST I 92 I 3 I SEPTEMBER. 1987
481
0.3
NS ~
0.2
+.) • .-4 .....-4 .~
,.Q ~
~
0
c, ~
0.1
o
o
1 2 3 4 5 6 )7 Number of deaths per month
FIGURE 1. Distribution of the number of asthma deaths per month during the retrospective part of the study (solid line) fitted to a Poisson distribution fA. = 2.75 (dashed line). No statistical difference (xl == 1.90, NS).
Prospective Study A total of 259 emergency calls from asthmatic patients was recorded during the study period; 243 patients (94 percent) were taken to the hospital in an emergency care ambulance; the remaining 16 patients refused admission to the hospital and were left at home after treatment. During this period, only four deaths (1.5 percent) were observed. One patient refused admission to hospital and died at home two hours after he was examined by the physician. Three other patients developed a severe and rapid attack resulting in prompt cardiac arrest and could not be resuscitated. According to the Poisson distribution of deaths in the retrospective study, the probability observing one or less death per month during a six-month period, was only 0.0019, and the expected value of asthma deaths during this period was 16 to 17 deaths. During the same seasonal period of the retrospective study (September to February), 17 deaths were observed in 1983 to 1984, and 24 in 1984 to 1985. The risk of dying from asthma after an emergency call to our unit decreased 6-fold compared to the retrospective study. The mortality rate dramatically improved, but the number of patients who experienced near-fatal or fatal asthma was consistent with the expected number of asthma fatalities according to the retrospective study as shown in Figure 2. Seventeen patients would have died if the behavior of the retrospective study had been applied. Eleven patients were found in cardiac or respiratory arrest by firemen and were successfully resuscitated. During transportation to the hospital, six other patients developed unexpected arrest. Peak 482
flow was determined in five patients who developed a respiratory arrest soon after: all values were sl00 L'min" (range 60 to 100). Peak flow was not measured in the other 12 patients because of cardiac or respiratory arrest. Mechanical ventilation was performed in 13 orotracheally intubated patients and transient ventilation with oxygen and a face mask was sufficient in the four other patients. All patients required salbutamol or epinephrine infusion using a motor-driven syringe-type pump and received intravenous corticosteroids. All of them were admitted into an intensive care unit and were discharged alive from the hospital. Table 1 shows the main data of the 21 patients who experienced fatal or near-fatal asthma. Eighteen patients had used ~-mimetic inhaler before our arrival. No other drug has been taken by the remaining three patients. Only one patient was a smoker and complained of exertional dyspnea. The 20 other patients
...c1
13o
S
6
••
5
••
a
4
••• •••
000
3
••• ••••
: :
P(O.OO2
2
••••
1
o
:...........:
B
E F 0 R E
0A F T E R
a
: : :
0
............
E X P E C T
~
2. Comparison of the mortality rate from asthma before (mean 2.75 death/month) and after (mean 0.66 death/month) our prehospital scheme. Dotted rectangle and open circles represent the expected mortality rate if patients who experienced near-fatal asthma had not been resuscitated (mean 3.50 death/month). Each circle represents one month, and the rectangles the average. FIGURE
Prevention of Fatal Asthma (BanIcX, RIou)
Table I-MtJin Datafrom Patients tDith Near-FtJIal (1 to 17) or Fatal (18 to 21) Asthma During Prospective Study* Asthmatic Illness
Patient No
Age, Yr
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 m ±SEM 18 19 20 21 m ±SEM
23 40 18 64 46
20 32 19 76 11 39 25 26 64 19 39 42 35 ±5 43 22 39 19 31 ±6
Sex
F
M
F F F
F M F M M M M F
F
F M F
F
F M F
Age at Onset of Asthm~ Yr
9 29 8 34
24 8 22 8 26 6 19 21 12
54
7 9 18 18 ±3 16 11 24 6 14 ±4
TIlDe Interval Since Last Hospitalization Yr, m, d 2yr 11 yr None 10 yr 5yr 6yr 10 yr 5 yr 15 d 5 yr None 4 yr 2m None 12 yr 1 mP 2 yr
None 2yr 3mP 5yr
Routine Drug 'Ireatment
l: l: l: l: Pi
l: l: l: l: T
Asthma Attack Duration min
Pi Pi, Co Pi pi, Co
30 120 45
pi, Co pi, Co Pi Pi
45 15 20 30 20 10 25 40 45 30 25
l: Co Pi
l: Pi
None
1: Pi
pi, Co
1: pi, Co 1: Pi Pi
l: Pi, Co Pi
30 30
50 36
±6 180t
<60 <60 <60
Phase
Final
Contributing Factors
FA, min
PA, min
CRA CRA RA CRA RA CRA RA CRA CRA CRA CRA CRA CRA RA CRA RA RA
None Infectious bronchitis None None None Psychological Treatment withdrawal Treatment withdrawal Infectious bronchitis None Treatment withdrawal Infectious bronchitis Psychological Allergic Treatment withdrawal Treatment withdrawal None
CRA CRA CRA CRA
Treatment withdrawal None None None
5 7 5 4 4 6 6 5 3 3 4 6 7 4 5 5 6 5.0 ±0.3 7 4 5 6 5.5 ±0.6
9 11 11 12 5 10 6 8 7 5 7 7 9 9 9 12 10 8.6 ±0.5 21 18 9 10 14.5 ±3.0
*Yr denotes year; m, month; d, day; ~ previous controlled ventilation; l: theophylline; pi, p-mimetic inhaler; Co, oral corticosteroids; CRA, cardiorespiratory and RA, respiratory arrest; FA, time to firemens arrival after emergency call; PA, time to physicians arrival after emergency call. Data are expressed as m ± SEM. tPatient seen 120 minutes before death.
had no dyspnea. Only one patient used a home peakHow meter. The emergency care unit was called by the patient himself in seven cases and by a relative in 11 cases. A passer-by called the unit in the remaining three patients who experienced an asthma attack in the street and were dead before our arrival. All the 17 patients with near-fatal asthma were interviewed at home. The reasons for calling the emergency care unit were the unusual severity of the attack in all cases, and the delay involving general practitioner's arrival in five cases. The trial time was 241±13 days (range 153 to 341 days). None of these 17 patients was admitted to the hospital because of a severe attack during the trial time, but eight were admitted for asthma check-up. Only one patient died from asthma, at home, 153 days after his near-fatal attack of asthma. After leaving the hospital, these 17 patients received adequate prophylactic treatment. Optimal theophylline dosage was determined in all patients by serum concentration measurement, all of them received inhaled ~-mimetic whereas only 14 out of 17 had previNine patients received ously taken inhaled ~-mimetic. oral corticosteroids and two patients received inhaled
corticosteroids, whereas only seven had previously taken oral corticosteroids. Only one patient received cromoglycate. Fourteen among the 17 patients were advised by hospital physicians to administer, in case of severe attack of asthma, a subcutaneous injection of a ~-mimetic and to call a mobile emergency care unit soon after, Nevertheless, none of these 14 patients had the opportunity to do so, since they did not experience another severe attack. The sample of patients with fatal asthma was too small to allow comparison between patients with nearfatal asthma. Nevertheless, the delay of physicians arrival seemed to be higher in patients with fatal asthma (14.5±3.0 vs 8.6±0.5 minutes). Peak-Bowmeasured in the last 101 consecutive asthmatic patients who did not experience near-fatal asthma was 92±29 L'mln " (86 percent were sl50 Izmin "), Comparison
ofthe Two Periods
Table 2 compares the activity of our prehospital emergency care unit between the two periods. The total activity and the average number of emergency calls from asthmatic patients rose during the prospective CHEST I 92 I 3 I SEPTEMBER, 1987
483
Table 2-Compariaon ofActivity of Prehoapital Emergency Care Unit Between Two Periods of Study· Retrospective Study (january 1983 to August 1985)
Prospective study (September 1985 to February 1986)
p
8515±65
11799± 123
<0.001
778± 12
836± 10
<0.001
3O±1
43±5
<0.01
No. of emergency calls per month No. of patients taken to hospital per month No. of emergency calls from asthmatic patients per month
·The increase in our activity was expected since our activity rose 15 percent a year from 1980 to 1985, Student's t-test. Data are expressed as m±SEM.
part of the study. This increase in the activity of our unit was expected since the mean rate of increase ofour total activity was + 15 ± 4 percent a year, from 1980 to 1985.
Table 3 compares patients who experienced fatal or near-fatal asthma between the two periods. There was no significant difference in the two populations between the two periods, except for delay in physician's arrival. DISCUSSION
The results of our study suggest that the mortality rate of asthma was dramatically decreased, and that most asthma deaths are preventable. Nevertheless, we must admit that the patients who died and never called anybody were not counted in our study and that four patients died in spite of our scheme. Nevertheless, during a six-month period, 17patients in circulatory or respiratory arrest were successfully resuscitated and were discharged alive from the hospital without sequellae. The question arises if there was any bias since our study was not controlled. As delay in arrival of medical help was noted in the retrospective part of the study, we considered a controlled trial unethical, according to the opinion of previous authors.Y We were unable to compare the whole population of asthmatic patients
who called our unit during the two periods of the study. Moreover, very few data concerning the patients who called and were not examined by a physician were available. However, the comparison between the two periods showed that both the total activity and the rate of emergency calls from asthmatic patients rose; thus, a spontaneous decrease in asthma deaths in our unit is not a likely explanation. Moreover, the number of patients who experienced fatal or near-fatal asthma during the prospective study was consistent with the results of the retrospective study. The comparison of the patients who experienced fatal or near-fatal asthma between the two periods did not show any significant difference. However, no patient who experienced arrest before the physician's arrival was resuscitated during the retrospective study, whereas 11 among 14 patients who were found in arrest during the prospective study were successfully resuscitated. No information about our study was given to the population or to general practitioners that would have biased our results. Our activity increased between the two parts of the study as expected. The mean rate of increase of our activity was + 15percent per year since 1980, and thus, was probably not related to our study. These considerations suggest that our scheme actually prevented some asthma deaths. Since the 1960s, reports of asthma deaths dramat-
Table 3-Compariaon of Main Data Obtained from Patients WIao Eqerience Fatal or Near-Fatal Aathma Between Two Periods of Study* Retrospective Study (90 Patients)
Prospective Study (21 Patients)
p
Age, yr
38±2
34±5
NS
Age at the onset of asthma, yr
22±1
18±3
NS
Routine drug treatment: Theophylline No(%) p-mimetic No(%) Corticosteroid No(%)
69 (77) 79 (88) 32 (36)
15 (71) 18 (86) 8 (38)
NS NS NS
8 (9)
2 (10)
NS
Presence of contributing factors to the attack No(%)
39 (43)
12 (57)
NS
Duration of the attack :s 1 hour No(%)
67 (74)
19 (90)
NS
Delay in firemen arrival, min
5.5±0.2
5.1±0.3
NS
28.3±0.7
9.7±0.6
<0.001
Previous mechanical ventilation No(%)
Delay in physician arrival, min
·Students t test or Fisher's exact method. Data are expressed as m ± SEM, or number (No) and percentage (%). Prevention of Fatal Asthma (Baniot, Rlou)
ically increased, whereas mortality rate from other respiratory diseases decreased. 1 In 1980, the number of deaths from asthma was 1.3/100,000 in the United States and 31100,000 in England and Wales, but 81100,000 in New-Zealand which has the highest reported value.v" The incidence of asthma deaths in France remains unknown because of the lack of precise epidemiologic studies. Although this study failed to provide precise epidemiologic data, we were able to give a lower limit of the incidence of asthma deaths in Paris: 1.05/100,000 persons. This suggests that fatal asthma is also a worrisome problem in France since patients who died and never called anybody or called other medical help were not counted in our study. Our retrospective study showed that 9 percent of asthmatic patients who called our emergency care unit died, suggesting that some asthmatic patients (or their relatives) were able to assess the severity of asthma attacks since they called. Many reports have stated that the patients, their relatives, and their medical practitioner usually fail to assess the severity of asthma attacks.2.3.5 Nevertheless, these reports were sometimes conflicting since they also reported that a delay in reaching the hospital was often identified. Perhaps some of the patients that died during transportation to the hospital accurately assessed themselves. Shim and Williams" found that patients were more accurate than physicians in predicting the severity of the attacks. Our study did not demonstrate that all asthmatic patients are accurate in assessing their own severity but that some of them do. Our study demonstrates that these patients can be saved if prehospital management is improved. However, a 9 percent incidence of deaths among emergency calls from asthmatic patients compelled us to reconsider the prehospital management of these emergency calls. The development of an index to gauge the severity of an asthma attack was proven disappointing when tested in acute-care settings." Thus, we made the assumption that, when an asthmatic patient called for emergency care, the attack was severe and might be fatal, whatever the apparent severity of the attack. The low peak-flows measured in patients who called our unit confirmed they actually had a severe attack of asthma. Peak-Howmeasurement is a less reliable index of airway obstruction than FEVb but it is the only objective measurement available in the field. However, a patient is undoubtedly critically ill if the peakHow is less than 200 L-min- 1.14 Delay at every stage of care was an important factor involved in asthma deaths in the British Thoracic Association survey and in previous studies. 5Crompton and eolleagues'" developed a self-admission service for acute asthma. This scheme was considered to make an impact on the mortality rate, although it is probably only useful in cooperative patients. During our study,
the delay of medical help was reduced from 28 to 10 minutes after the emergency call. This enabled us to give the patients the same care that they would have received in the emergency room of the hospital, but only on the average of ten minutes after the emergency call. Reduction in delay of care surely accounted for the decrease in asthma deaths in our study. Moreover, the delay of care seemed to be higher in the four patients who died despite our prehospital scheme. As it was stated in previous studies,2.4,5 we found that near-fatal asthma occurred in patients who had the disease for many years and had no objective measurement of airflow limitation. Nevertheless, we must point out that only two patients previously experienced a lifethreatening attack requiring mechanical ventilation, and that only four patients were recently discharged from the hospital. A contributing factor was identified in 12 patients, especially treatment withdrawal. During the follow-up of patients successfully resuscitated, none of them experienced emergency admission to the hospital, and only one patient died. But these patients received adequate prophylactic treatment after they were discharged from the hospital, and management of their disease was improved, since eight out of 17 patients were admitted to the hospital for an asthma check-up during the trial time. Although these data concerned few patients, they were probably more accurate than those obtained in previous studies which were performed in a retrospective manner by interviewing relatives or the practitioner of dead patients, since our data were obtained by interviewing the patients who experienced near-fatal asthma, soon after they were discharged from the hospital. Most of these near-fatal attacks of asthma were documented as sudden unexpected attacks. Some authors" emphasized that up to 25 percent of deaths occur within 30 minutes; in our study, the duration of near-fatal attack was within 30 minutes in 11 patients (52 percent) and within two hours in all patients. This suggests that fatal asthma is not necessarily related to a prolonged attack, and that fatal asthma is often due to sudden severe attacks, ccout of a clear blue sky," as it was stated by Stableforth." Arnold et al" suggested that the management of acute severe asthma depends on the speed of onset of the attack. If the severe attacks evolve slowly, it is safe to concentrate resources on improved management at home by the general practitioner and the patients himself. Whereas if the severe attacks evolve rapidly, then a self-referral asthma service or improvement of prehospital management are more appropriate. Since our study suggests that most fatal or near-fatal asthma is related to sudden severe attacks, then resources might be concentrated on the development of a prehospital scheme to decrease asthma mortality. CHEST I 92 I 3 I SEPTEMBER, 1987
485
CONCLUSIONS
A better recognition of asthma, because failure to diagnose precludes effective treatment, education of asthmatic patients and all professionals likely to come into contact with asthma, and the development of selfreferral admission services for asthmatic patients are probably necessary. But development of prehospital emergency care schemes are of paramount importance and may prevent some unnecessary deaths, Emergency calls from asthmatic patients must be considered as related to a severe attack of asthma that may be fatal, since there is no method to evaluate the severity of an attack that evolves rapidly and because of the risk of sudden death. ACKNOWLEDGMENT: We wish to thank the staff of the Fire Brigade of Paris for their continuous help in this study. We are particularly indebted to Colonel Rene Noto, M. D., who controls the Emergency Medical Service of the Fire brigade of Paris and helped develop the" prehospital scheme fpr asthmatic patients. We are indebted to Pr. Franeots Clergue, M.D., and to Michel Aubier, M.D., for reviewing the manuscript and for their valuable advices. We are indebted to Francoise Neukirch for her assistance in statistical .ysis.
m:
4 5 6 7
8
9
10 11 12 13
REFERENCES
1 Jackson Beaglehole R, Rea HH, Sutherland DC. Mortality from asthma: a new epidemic in New Zealand. Br Moo J 1982; 285:771-74 2 British Thoracic Association. Death from asthma in two regions of England. Br Med J 1982; 285:1251-55 3 Johnson AJ, Nunn AJ, Somner AR, Stableforth DE, Stewart CJ.
14 15 16
Circumstances of death from asthma. Br Med J 1984; 288: 1870-72 Sears MR, Rea HH, Beaglehole R, Gillies AJD, Hoest PE, O'Donnell ~ et ale Asthma mortality in New Zealand: a two year national study. N Z J 1985; 98:271-75 Benatar SR. Fatal asthma. N Engl J Med 1985; 314:423-29 Crompton GK, Grant IWB. Edinburgh emergency asthma admission service. Br Med J 1975; 4:680-82 Crompton GK, Grant lWB, Bloomfield ~ Edinburgh emergency asthma admission service: report on 10 years' experience. Br Med J 1979; 2:1199-1201 Anderson HR, Bailey ~ West S. Trends in the hospital care of acute childhood asthma 1970-8: a regional study. Br Med J 1980; 281:1191-94 Hilton S, Sibbald 8, Anderson HR, Freeling ~ Controlled evaluation of the effects of patients education on asthma morbidity in general practice. Lancet 1986; 1:26-29 Institut National de la Statistique et des Etudes Economiques. Recensement general de 1a population de 1982. INSEE ed, Paris Steel RGD, Torrie JH. Principles and procedures of statistics. New York: McGraw-Hill, 1960:388-99 Shim CS, Williams MH. Evaluation of the severity of asthma: patients versus physicians. Am J Med 1980; 68:11-3 RoseCC, MurphyJG, SchwartzJS. Perfonnanceofanindexpredicting the response of patients with acute bronchial asthma to intensive emergency department treatment. N Eng} J Med 1984; 310:573-77 Edelson JD, Rebuck AS. The clinical assessment of severe asthma. Arch Intern Med 1985; 145:321-23 Stableforth D. Death from asthma. Thorax 1983; 38:801-05 Arnold AG, Lane DJ, Zapata E. The speed of onset and severity of acute severe asthma. Br J Dis Chest 1982; 76:157-63
Moo
Salvatore Maugeri Prize in Occupational Medicine and Rehabilitation The Fondazione Clinica del Lavoroof Pavia, Italy announces this biennial prize to be awarded to researchers of any nationality for their original, recent contribution to the development of occupational medicine and rehabilitation. Eight copies of the manuscript, written in English, should be sent by January 31 to: Fondazione Clinica del Lavoro di Pavia, Segreteria della Commissione Giudicatrice per il conferimento del Premio Salvatore Maugeri, Via P Azzario19, 27100 Pavia, Italy. Complete information may be obtained from the Commissione.
Preventionof Fatal Asthma (Barria, RIou)
Over a 31-month period, 980 calls from asthmatic patients were received at the switchboard office of a prehospital emergency care unit. A total of 90 patients (9 percent) died before receiving any medical help, and 216 (22 percent) patients were taken to the hospital with an emergency care ambulance where none of them died. We made the assumption that, when an asthmatic patient calls an emergency care unit, the attack is severe and might be fatal. A prospecti.e study was performed during a six-month period to prevent these asthma deaths: 259 calls from asthmatic patienb were received. For each emergency call from asth-
matic patients, paramedical help (delay: 5.1:1:0.3 minutes) and an emergency care ambulance (delay: 9.7:1:0.6 minutes) were immediately sent, Only four patients died during this period, Emergency calls from asthmatic patients must be considered as related to a severe attack that might be fatal. Fatal asthma is often related to a severe attaCk that evolves rapidl~ Some asthmatic patients are able to assess the ·severity of asthma attacks, and prehospital emergency care schemes for asthmatic patients are actually able to prevent some asthma deaths.
phYSicianS are concerned that mortality from asthma fails to decline despite modern treatment. 1 The literatureU provided some preliminary conclusions about asthma deaths as follows: (1) most of the asthmatic patients died at home or during transportation to the hospital; (2)the severity ofthe attack was difficult to assess by the asthmatic patient, his relatives, and his medical practitioner; (3)delays in the arrival of medical aid or in reaching a hospital were shown to be deleterious; (4) most asthmatic deaths could be prevented since avoidable factors were identified in the events that led to more than 80 percent ofdeaths." and (5)very rapid progress of some severe attacks could have contributed to the mortality, and these sudden deaths are difficult to prevent. Crompton et al6•7 developed an emergency asthma service using self-referral to hospital for asthmatic patients and found a lower mortality rate among patients with access to this service than that among patients with access to other asthma services in the same area. Nevertheless, some authors" found that, despite a great increase in hospital admissions, no reduction in mortality rate was observed using a similar scheme in children. It is likely that selfadmission services are solely useful in cooperative patients. A controlled evaluation of the effects of two educational programs on asthma morbidity was recently reported by Hilton et al." These authors demonstrated that these programs were ineffective when applied to a general practice population, especially considering the
incidence of severe attacks. This study suggested that development of educational programs is probably not the only way to reduce asthma mortality. The aim of this study was to decrease the incidence of fatal asthma with improvement in prehospital management of emergency calls from asthmatic patients. This study was based on an assumption: asthmatic patients who call an emergency care unit actually have a severe attack that might be fatal. Thus, a standardized behavior was decided, whatever the apparent severity of the asthma attack.
-From the Service de Sante de la Brigade des Sapeurs Pompiers de Paris, and the Departement d'Anesthesle-Reanimation, Groupe Hospitalier Piti6-S81petriere, Universlte de Paris, France. Manuscript received October 9; revision accepted February 26. Reprint requeat8: Dr. Barriot, BSPp, 47 Rue Saint-Fargeau, 75020 Ibm, France
480
METHODS
The study involved two parts. A retrospective study was performed to analyze data from asthma deaths in our unit and to enable comparison with the prospective part of the study. Moreover, in order to confirm or show up the weakness of our assumption that patients who called our unit actually had a severe attack of asthma, peak-flow was systematically measured in asthmatic patients who called our unit.
Description of the Prehospital Emergency Care Unit The unit depends on the Fire Brigade of Paris. Emergency calls are received at a switchboard office where a chief physicJan makes an appropriate decision as fOllows: (1)gives advice to die patients or his relatives; (2) sends firemen trained in external cardiac massage and ventilation with oxygen and a face mask (paramedical aid); (3) sends an emergency care ambulance with a physician. Firemen or the physician inform the chiefphysician by either radio or phone, about the patients clinical status, and an appropriate decision is made concerning the opportunity of hospital admission with an emergency care ambulance. For each patient transported to the hospital with an emergency care ambulance, a standardized data sheet is completed by the physician, giving some details about the history of the patient, clinical findings, and treatment given during the transport to the hospital. Firemen are based in 78 different sites in Paris and its environs, and can reach any patient within ten minutes after the emergency call. Six emergency care ambulances are based in five different sites and can reach any patient within 30 minutes. The phone of the unit is the one of all Fire Brigades (number 18) throughout the country, is written on all telephone sets, and is known by everybody. PnMnion of Fetal Asthma (8tIrtk1, RJou)
Our unit receives emergency calls from a well-defined area of Paris and its environs. The population of this area was evaluated using data obtained during the 1982 census of the "Institut National de la Statistique et des Etudes Economiques.P'
Definition An asthmatic patient's call was defined as an emergency call concerning a patient who experienced a dyspneic attack and during which the word cc asthma" was pronounced, whoever the person who called (the patient himself a relative, or a general practitioner). Near-fatal asthma was defined as an attack of asthma in a patient successfully resuscitated from cardiac or respiratory arrest in two situations as follows: (1) arrest supervened before the physician's arrival, or (2) arrest supervened after the physician's arrival and before reaching the hospital, but unexpected according to the initial clinical status assessed by the physician.
Retrospective Study The retrospective study was performed from January 1983 to August 1985. The number of emergency calls from asthmatic patients received at the switchboard office of our unit was recorded every month, as well as the number of patients who were judged critically ill, and thus, taken to the hospital using an emergency care ambulance. The number of patients who called, and the number of patients taken to the hospital during this period were also recorded to compare the activity of our unit during the retrospective and the prospective parts of the study. As a matter of fact, precise data from asthmatic patients who called and were not taken to the hospital with an emergency care ambulance, were not available. All deaths related to asthma from January 1983 to August 1985 were studied. The criteria for inclusion were as follow: (1) a convincing clinical history of asthma, ie, evidence of Significant reversibility of airway obstruction as shown by objective measurement or prompt response to treatment with bronchodilators; (2) a first episode of airway obstruction before age 50. An agreement of the two co-ordinators who independently examined the data-sheet was necessary for inclusion. In including our patients, we were aware of the difficulties of interpreting "a clinical convincing history of asthma." There must be reservations about the accuracy of making a diagnosis of asthma in some patients as in any retrospective study dealing with fatal asthma. For asthma to be accepted as a cause of death, the two co-ordinators' opinion had to be identical. Attention was particularly focused on associated diseases to determine whether the patient died of asthma: patients with chronic obstructive pulmonary disease, emphysema, and heart disease were excluded. Patients were considered to have either a rapid (:51 hour) or a prolonged (>1 hour) attack of asthma.
Prospective Study The prospective study was performed from September 1985 to February 1986. It was decided that, when an asthmatic patient called, both a fire team and an ambulance with a physician, were immediately sent to him and the patient was taken to the hospital, whatever the apparent severity of the asthma attack. Information about this study was given to all the physicians of our unit, chiefs of each team offiremen, and to the whole staff of the switchboard office. No information was given to any media or to general practitioners during this study, and none of our physicians was in charge of asthmatic patients outside our unit. A simple questionnaire was completed at the switchboard office for each emergency call from asthmatic patients, and the usual standardized data-sheet was completed by the physician. A questionnaire was completed by one of us, giving details on the asthmatic illness and the circumstances of the asthma attack, by interviewing the patients who experienced near-fatal asthma. Interviews were performed at home, after the patients had been discharged from the hospital. The follow-up status (dead or alive, occurrence of any emergency admission to an hospital
during trial time or not) was determined by telephone call to all surviving patients every month, until August 15 to 20, 1986 (closing date), and the trial time of each patient was recorded. The trial time was defined as the time to the last telephone call after the near-fatal attack of asthma. During the prospective study, peak-flow was systematically measured in the last 101 consecutive asthmatic patients who called our emergency care unit and did not experience near-fatal asthma. The peak-flow value for each patient was the best of three measurements.
Statistical Analysis The distribution of the number of asthma deaths per month during the retrospective study was fitted to a Poisson distribution using a X2 test as previously described by Steel and Torrie. U According to a Poisson distribution, the probability of observing k deaths in a month is given by: P(k) = e-"'· JAok • kl- 1, IJ. being the average number of deaths per month. The probability of the mortality rate observed during the prospective study was calculated using this Poisson distribution. Comparison between the two periods of the study was performed using two-tailed Student's t-test for unpaired data and Fishers exact method or X2 test whenever appropriate. A p value <0.05 was necessary to reject a null hypothesis. Data were expressed as mean ± standard error on the mean (m ± SE M). RESULTS
Retrospective Study Some 980 emergency calls from asthmatic patients were recorded during the study period. A total of 216 (22 percent) of these patients were taken to the hospital with an emergency care ambulance and none of them died. Ninety (9.2 percent) asthmatic patients who called died; 36 asthmatic deaths occurred in 1983; 31 in 1984; and 23 from January to August 1985. A total of 21 (23 percent) patients were found in respiratory or cardiorespiratory arrest by their relatives or a practitioner. Death of the remaining 69 (77 percent) patients was considered as rapid in 47 (52 percent) patients or prolonged episode of respiratory distress in 22 (24 percent) patients; in these 69 (77 percent) patients, death occurred before any medical aid or during the transportation to the hospital in a common ambulance or in a private cal: A total of 66 patients (73 percent) surely used l3-mimetic inhaler before our arrival, and ten patients (11 percent) probably used l3-mimetic inhaler: No other drug was taken by the remaining 23 patients (26 percent) before our arrival. The number of deaths per month was shown to be correctly predicted by a Poisson distribution (JL = 2.75 death/month) as shown in Figure 1. During this period, no asthmatic patient who experienced cardiorespiratory arrest or respiratory arrest before arrival of the physician, was successfully resuscitated. The population which depended on our unit was estimated to be 3,584,398 persons. Since the mean number of asthma deaths per year was 34 during the retrospective study, the lower limit of the incidence of asthma deaths in Paris was 1.05/100,000 persons. CHEST I 92 I 3 I SEPTEMBER. 1987
481
0.3
NS ~
0.2
+.) • .-4 .....-4 .~
,.Q ~
~
0
c, ~
0.1
o
o
1 2 3 4 5 6 )7 Number of deaths per month
FIGURE 1. Distribution of the number of asthma deaths per month during the retrospective part of the study (solid line) fitted to a Poisson distribution fA. = 2.75 (dashed line). No statistical difference (xl == 1.90, NS).
Prospective Study A total of 259 emergency calls from asthmatic patients was recorded during the study period; 243 patients (94 percent) were taken to the hospital in an emergency care ambulance; the remaining 16 patients refused admission to the hospital and were left at home after treatment. During this period, only four deaths (1.5 percent) were observed. One patient refused admission to hospital and died at home two hours after he was examined by the physician. Three other patients developed a severe and rapid attack resulting in prompt cardiac arrest and could not be resuscitated. According to the Poisson distribution of deaths in the retrospective study, the probability observing one or less death per month during a six-month period, was only 0.0019, and the expected value of asthma deaths during this period was 16 to 17 deaths. During the same seasonal period of the retrospective study (September to February), 17 deaths were observed in 1983 to 1984, and 24 in 1984 to 1985. The risk of dying from asthma after an emergency call to our unit decreased 6-fold compared to the retrospective study. The mortality rate dramatically improved, but the number of patients who experienced near-fatal or fatal asthma was consistent with the expected number of asthma fatalities according to the retrospective study as shown in Figure 2. Seventeen patients would have died if the behavior of the retrospective study had been applied. Eleven patients were found in cardiac or respiratory arrest by firemen and were successfully resuscitated. During transportation to the hospital, six other patients developed unexpected arrest. Peak 482
flow was determined in five patients who developed a respiratory arrest soon after: all values were sl00 L'min" (range 60 to 100). Peak flow was not measured in the other 12 patients because of cardiac or respiratory arrest. Mechanical ventilation was performed in 13 orotracheally intubated patients and transient ventilation with oxygen and a face mask was sufficient in the four other patients. All patients required salbutamol or epinephrine infusion using a motor-driven syringe-type pump and received intravenous corticosteroids. All of them were admitted into an intensive care unit and were discharged alive from the hospital. Table 1 shows the main data of the 21 patients who experienced fatal or near-fatal asthma. Eighteen patients had used ~-mimetic inhaler before our arrival. No other drug has been taken by the remaining three patients. Only one patient was a smoker and complained of exertional dyspnea. The 20 other patients
...c1
13o
S
6
••
5
••
a
4
••• •••
000
3
••• ••••
: :
P(O.OO2
2
••••
1
o
:...........:
B
E F 0 R E
0A F T E R
a
: : :
0
............
E X P E C T
~
2. Comparison of the mortality rate from asthma before (mean 2.75 death/month) and after (mean 0.66 death/month) our prehospital scheme. Dotted rectangle and open circles represent the expected mortality rate if patients who experienced near-fatal asthma had not been resuscitated (mean 3.50 death/month). Each circle represents one month, and the rectangles the average. FIGURE
Prevention of Fatal Asthma (BanIcX, RIou)
Table I-MtJin Datafrom Patients tDith Near-FtJIal (1 to 17) or Fatal (18 to 21) Asthma During Prospective Study* Asthmatic Illness
Patient No
Age, Yr
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 m ±SEM 18 19 20 21 m ±SEM
23 40 18 64 46
20 32 19 76 11 39 25 26 64 19 39 42 35 ±5 43 22 39 19 31 ±6
Sex
F
M
F F F
F M F M M M M F
F
F M F
F
F M F
Age at Onset of Asthm~ Yr
9 29 8 34
24 8 22 8 26 6 19 21 12
54
7 9 18 18 ±3 16 11 24 6 14 ±4
TIlDe Interval Since Last Hospitalization Yr, m, d 2yr 11 yr None 10 yr 5yr 6yr 10 yr 5 yr 15 d 5 yr None 4 yr 2m None 12 yr 1 mP 2 yr
None 2yr 3mP 5yr
Routine Drug 'Ireatment
l: l: l: l: Pi
l: l: l: l: T
Asthma Attack Duration min
Pi Pi, Co Pi pi, Co
30 120 45
pi, Co pi, Co Pi Pi
45 15 20 30 20 10 25 40 45 30 25
l: Co Pi
l: Pi
None
1: Pi
pi, Co
1: pi, Co 1: Pi Pi
l: Pi, Co Pi
30 30
50 36
±6 180t
<60 <60 <60
Phase
Final
Contributing Factors
FA, min
PA, min
CRA CRA RA CRA RA CRA RA CRA CRA CRA CRA CRA CRA RA CRA RA RA
None Infectious bronchitis None None None Psychological Treatment withdrawal Treatment withdrawal Infectious bronchitis None Treatment withdrawal Infectious bronchitis Psychological Allergic Treatment withdrawal Treatment withdrawal None
CRA CRA CRA CRA
Treatment withdrawal None None None
5 7 5 4 4 6 6 5 3 3 4 6 7 4 5 5 6 5.0 ±0.3 7 4 5 6 5.5 ±0.6
9 11 11 12 5 10 6 8 7 5 7 7 9 9 9 12 10 8.6 ±0.5 21 18 9 10 14.5 ±3.0
*Yr denotes year; m, month; d, day; ~ previous controlled ventilation; l: theophylline; pi, p-mimetic inhaler; Co, oral corticosteroids; CRA, cardiorespiratory and RA, respiratory arrest; FA, time to firemens arrival after emergency call; PA, time to physicians arrival after emergency call. Data are expressed as m ± SEM. tPatient seen 120 minutes before death.
had no dyspnea. Only one patient used a home peakHow meter. The emergency care unit was called by the patient himself in seven cases and by a relative in 11 cases. A passer-by called the unit in the remaining three patients who experienced an asthma attack in the street and were dead before our arrival. All the 17 patients with near-fatal asthma were interviewed at home. The reasons for calling the emergency care unit were the unusual severity of the attack in all cases, and the delay involving general practitioner's arrival in five cases. The trial time was 241±13 days (range 153 to 341 days). None of these 17 patients was admitted to the hospital because of a severe attack during the trial time, but eight were admitted for asthma check-up. Only one patient died from asthma, at home, 153 days after his near-fatal attack of asthma. After leaving the hospital, these 17 patients received adequate prophylactic treatment. Optimal theophylline dosage was determined in all patients by serum concentration measurement, all of them received inhaled ~-mimetic whereas only 14 out of 17 had previNine patients received ously taken inhaled ~-mimetic. oral corticosteroids and two patients received inhaled
corticosteroids, whereas only seven had previously taken oral corticosteroids. Only one patient received cromoglycate. Fourteen among the 17 patients were advised by hospital physicians to administer, in case of severe attack of asthma, a subcutaneous injection of a ~-mimetic and to call a mobile emergency care unit soon after, Nevertheless, none of these 14 patients had the opportunity to do so, since they did not experience another severe attack. The sample of patients with fatal asthma was too small to allow comparison between patients with nearfatal asthma. Nevertheless, the delay of physicians arrival seemed to be higher in patients with fatal asthma (14.5±3.0 vs 8.6±0.5 minutes). Peak-Bowmeasured in the last 101 consecutive asthmatic patients who did not experience near-fatal asthma was 92±29 L'mln " (86 percent were sl50 Izmin "), Comparison
ofthe Two Periods
Table 2 compares the activity of our prehospital emergency care unit between the two periods. The total activity and the average number of emergency calls from asthmatic patients rose during the prospective CHEST I 92 I 3 I SEPTEMBER, 1987
483
Table 2-Compariaon ofActivity of Prehoapital Emergency Care Unit Between Two Periods of Study· Retrospective Study (january 1983 to August 1985)
Prospective study (September 1985 to February 1986)
p
8515±65
11799± 123
<0.001
778± 12
836± 10
<0.001
3O±1
43±5
<0.01
No. of emergency calls per month No. of patients taken to hospital per month No. of emergency calls from asthmatic patients per month
·The increase in our activity was expected since our activity rose 15 percent a year from 1980 to 1985, Student's t-test. Data are expressed as m±SEM.
part of the study. This increase in the activity of our unit was expected since the mean rate of increase ofour total activity was + 15 ± 4 percent a year, from 1980 to 1985.
Table 3 compares patients who experienced fatal or near-fatal asthma between the two periods. There was no significant difference in the two populations between the two periods, except for delay in physician's arrival. DISCUSSION
The results of our study suggest that the mortality rate of asthma was dramatically decreased, and that most asthma deaths are preventable. Nevertheless, we must admit that the patients who died and never called anybody were not counted in our study and that four patients died in spite of our scheme. Nevertheless, during a six-month period, 17patients in circulatory or respiratory arrest were successfully resuscitated and were discharged alive from the hospital without sequellae. The question arises if there was any bias since our study was not controlled. As delay in arrival of medical help was noted in the retrospective part of the study, we considered a controlled trial unethical, according to the opinion of previous authors.Y We were unable to compare the whole population of asthmatic patients
who called our unit during the two periods of the study. Moreover, very few data concerning the patients who called and were not examined by a physician were available. However, the comparison between the two periods showed that both the total activity and the rate of emergency calls from asthmatic patients rose; thus, a spontaneous decrease in asthma deaths in our unit is not a likely explanation. Moreover, the number of patients who experienced fatal or near-fatal asthma during the prospective study was consistent with the results of the retrospective study. The comparison of the patients who experienced fatal or near-fatal asthma between the two periods did not show any significant difference. However, no patient who experienced arrest before the physician's arrival was resuscitated during the retrospective study, whereas 11 among 14 patients who were found in arrest during the prospective study were successfully resuscitated. No information about our study was given to the population or to general practitioners that would have biased our results. Our activity increased between the two parts of the study as expected. The mean rate of increase of our activity was + 15percent per year since 1980, and thus, was probably not related to our study. These considerations suggest that our scheme actually prevented some asthma deaths. Since the 1960s, reports of asthma deaths dramat-
Table 3-Compariaon of Main Data Obtained from Patients WIao Eqerience Fatal or Near-Fatal Aathma Between Two Periods of Study* Retrospective Study (90 Patients)
Prospective Study (21 Patients)
p
Age, yr
38±2
34±5
NS
Age at the onset of asthma, yr
22±1
18±3
NS
Routine drug treatment: Theophylline No(%) p-mimetic No(%) Corticosteroid No(%)
69 (77) 79 (88) 32 (36)
15 (71) 18 (86) 8 (38)
NS NS NS
8 (9)
2 (10)
NS
Presence of contributing factors to the attack No(%)
39 (43)
12 (57)
NS
Duration of the attack :s 1 hour No(%)
67 (74)
19 (90)
NS
Delay in firemen arrival, min
5.5±0.2
5.1±0.3
NS
28.3±0.7
9.7±0.6
<0.001
Previous mechanical ventilation No(%)
Delay in physician arrival, min
·Students t test or Fisher's exact method. Data are expressed as m ± SEM, or number (No) and percentage (%). Prevention of Fatal Asthma (Baniot, Rlou)
ically increased, whereas mortality rate from other respiratory diseases decreased. 1 In 1980, the number of deaths from asthma was 1.3/100,000 in the United States and 31100,000 in England and Wales, but 81100,000 in New-Zealand which has the highest reported value.v" The incidence of asthma deaths in France remains unknown because of the lack of precise epidemiologic studies. Although this study failed to provide precise epidemiologic data, we were able to give a lower limit of the incidence of asthma deaths in Paris: 1.05/100,000 persons. This suggests that fatal asthma is also a worrisome problem in France since patients who died and never called anybody or called other medical help were not counted in our study. Our retrospective study showed that 9 percent of asthmatic patients who called our emergency care unit died, suggesting that some asthmatic patients (or their relatives) were able to assess the severity of asthma attacks since they called. Many reports have stated that the patients, their relatives, and their medical practitioner usually fail to assess the severity of asthma attacks.2.3.5 Nevertheless, these reports were sometimes conflicting since they also reported that a delay in reaching the hospital was often identified. Perhaps some of the patients that died during transportation to the hospital accurately assessed themselves. Shim and Williams" found that patients were more accurate than physicians in predicting the severity of the attacks. Our study did not demonstrate that all asthmatic patients are accurate in assessing their own severity but that some of them do. Our study demonstrates that these patients can be saved if prehospital management is improved. However, a 9 percent incidence of deaths among emergency calls from asthmatic patients compelled us to reconsider the prehospital management of these emergency calls. The development of an index to gauge the severity of an asthma attack was proven disappointing when tested in acute-care settings." Thus, we made the assumption that, when an asthmatic patient called for emergency care, the attack was severe and might be fatal, whatever the apparent severity of the attack. The low peak-flows measured in patients who called our unit confirmed they actually had a severe attack of asthma. Peak-Howmeasurement is a less reliable index of airway obstruction than FEVb but it is the only objective measurement available in the field. However, a patient is undoubtedly critically ill if the peakHow is less than 200 L-min- 1.14 Delay at every stage of care was an important factor involved in asthma deaths in the British Thoracic Association survey and in previous studies. 5Crompton and eolleagues'" developed a self-admission service for acute asthma. This scheme was considered to make an impact on the mortality rate, although it is probably only useful in cooperative patients. During our study,
the delay of medical help was reduced from 28 to 10 minutes after the emergency call. This enabled us to give the patients the same care that they would have received in the emergency room of the hospital, but only on the average of ten minutes after the emergency call. Reduction in delay of care surely accounted for the decrease in asthma deaths in our study. Moreover, the delay of care seemed to be higher in the four patients who died despite our prehospital scheme. As it was stated in previous studies,2.4,5 we found that near-fatal asthma occurred in patients who had the disease for many years and had no objective measurement of airflow limitation. Nevertheless, we must point out that only two patients previously experienced a lifethreatening attack requiring mechanical ventilation, and that only four patients were recently discharged from the hospital. A contributing factor was identified in 12 patients, especially treatment withdrawal. During the follow-up of patients successfully resuscitated, none of them experienced emergency admission to the hospital, and only one patient died. But these patients received adequate prophylactic treatment after they were discharged from the hospital, and management of their disease was improved, since eight out of 17 patients were admitted to the hospital for an asthma check-up during the trial time. Although these data concerned few patients, they were probably more accurate than those obtained in previous studies which were performed in a retrospective manner by interviewing relatives or the practitioner of dead patients, since our data were obtained by interviewing the patients who experienced near-fatal asthma, soon after they were discharged from the hospital. Most of these near-fatal attacks of asthma were documented as sudden unexpected attacks. Some authors" emphasized that up to 25 percent of deaths occur within 30 minutes; in our study, the duration of near-fatal attack was within 30 minutes in 11 patients (52 percent) and within two hours in all patients. This suggests that fatal asthma is not necessarily related to a prolonged attack, and that fatal asthma is often due to sudden severe attacks, ccout of a clear blue sky," as it was stated by Stableforth." Arnold et al" suggested that the management of acute severe asthma depends on the speed of onset of the attack. If the severe attacks evolve slowly, it is safe to concentrate resources on improved management at home by the general practitioner and the patients himself. Whereas if the severe attacks evolve rapidly, then a self-referral asthma service or improvement of prehospital management are more appropriate. Since our study suggests that most fatal or near-fatal asthma is related to sudden severe attacks, then resources might be concentrated on the development of a prehospital scheme to decrease asthma mortality. CHEST I 92 I 3 I SEPTEMBER, 1987
485
CONCLUSIONS
A better recognition of asthma, because failure to diagnose precludes effective treatment, education of asthmatic patients and all professionals likely to come into contact with asthma, and the development of selfreferral admission services for asthmatic patients are probably necessary. But development of prehospital emergency care schemes are of paramount importance and may prevent some unnecessary deaths, Emergency calls from asthmatic patients must be considered as related to a severe attack of asthma that may be fatal, since there is no method to evaluate the severity of an attack that evolves rapidly and because of the risk of sudden death. ACKNOWLEDGMENT: We wish to thank the staff of the Fire Brigade of Paris for their continuous help in this study. We are particularly indebted to Colonel Rene Noto, M. D., who controls the Emergency Medical Service of the Fire brigade of Paris and helped develop the" prehospital scheme fpr asthmatic patients. We are indebted to Pr. Franeots Clergue, M.D., and to Michel Aubier, M.D., for reviewing the manuscript and for their valuable advices. We are indebted to Francoise Neukirch for her assistance in statistical .ysis.
m:
4 5 6 7
8
9
10 11 12 13
REFERENCES
1 Jackson Beaglehole R, Rea HH, Sutherland DC. Mortality from asthma: a new epidemic in New Zealand. Br Moo J 1982; 285:771-74 2 British Thoracic Association. Death from asthma in two regions of England. Br Med J 1982; 285:1251-55 3 Johnson AJ, Nunn AJ, Somner AR, Stableforth DE, Stewart CJ.
14 15 16
Circumstances of death from asthma. Br Med J 1984; 288: 1870-72 Sears MR, Rea HH, Beaglehole R, Gillies AJD, Hoest PE, O'Donnell ~ et ale Asthma mortality in New Zealand: a two year national study. N Z J 1985; 98:271-75 Benatar SR. Fatal asthma. N Engl J Med 1985; 314:423-29 Crompton GK, Grant IWB. Edinburgh emergency asthma admission service. Br Med J 1975; 4:680-82 Crompton GK, Grant lWB, Bloomfield ~ Edinburgh emergency asthma admission service: report on 10 years' experience. Br Med J 1979; 2:1199-1201 Anderson HR, Bailey ~ West S. Trends in the hospital care of acute childhood asthma 1970-8: a regional study. Br Med J 1980; 281:1191-94 Hilton S, Sibbald 8, Anderson HR, Freeling ~ Controlled evaluation of the effects of patients education on asthma morbidity in general practice. Lancet 1986; 1:26-29 Institut National de la Statistique et des Etudes Economiques. Recensement general de 1a population de 1982. INSEE ed, Paris Steel RGD, Torrie JH. Principles and procedures of statistics. New York: McGraw-Hill, 1960:388-99 Shim CS, Williams MH. Evaluation of the severity of asthma: patients versus physicians. Am J Med 1980; 68:11-3 RoseCC, MurphyJG, SchwartzJS. Perfonnanceofanindexpredicting the response of patients with acute bronchial asthma to intensive emergency department treatment. N Eng} J Med 1984; 310:573-77 Edelson JD, Rebuck AS. The clinical assessment of severe asthma. Arch Intern Med 1985; 145:321-23 Stableforth D. Death from asthma. Thorax 1983; 38:801-05 Arnold AG, Lane DJ, Zapata E. The speed of onset and severity of acute severe asthma. Br J Dis Chest 1982; 76:157-63
Moo
Salvatore Maugeri Prize in Occupational Medicine and Rehabilitation The Fondazione Clinica del Lavoroof Pavia, Italy announces this biennial prize to be awarded to researchers of any nationality for their original, recent contribution to the development of occupational medicine and rehabilitation. Eight copies of the manuscript, written in English, should be sent by January 31 to: Fondazione Clinica del Lavoro di Pavia, Segreteria della Commissione Giudicatrice per il conferimento del Premio Salvatore Maugeri, Via P Azzario19, 27100 Pavia, Italy. Complete information may be obtained from the Commissione.
Preventionof Fatal Asthma (Barria, RIou)