The Treatment of Status Asthmaticus

Abstract

Asthma has proved difficult to define (42, 103, in asthma often comes suddenly and unexpect-116) and physicians do not always agree about edly, and even experienced physicians may when a patient should be called asthmatic, have difficulty in judging the severity of an Status asthmaticus cannot be easier to define, attack. The patient may be a better judge in but it seems much more seldom that physicians this respect (122), but many asthmatics are not disagree about a diagnosis of status asthma-very sensitive to changes in airway obstruction, ticus. The term will be used here to denote a Rubinfeld & Pain (111) found that 15% were sustained attack of severe asthma that has not unable to sense a reduction in FEVj below 50% responded to the treatment administered by of predicted value. An objective assessment the patient and his doctor. It is a serious and ought usually to be the first step taken when potentially lethal phase of the disease and if dealing with a patient in status asthmaticus. It hospital admission is possible it will usually be can be carried out in a few minutes, and it required.provides both a baseline from which the proStatus asthmaticus is an acute aggravation gress of the patient can be assessed and a gradwhich may afflict the allergic as well as the ing of the severity of the attack, non-allergic asthmatic. It may occur at any age.The physical signs of wheezing, the use of but the risk seems to be greatest in the middle-accessory respiratory muscles and the presence aged patient with asthma of late onset. It also of pulsus paradoxus have not been found to be seems to afflict women more often than men. reliable indicators of the severity of asthma (71, In seven recent papers (7,25,58,61,70,118,121). 119) out of a total of 1,540 patients, 1,136 were Counting the heart rate is the simplest of females and 404 males, i.e. a ratio of about 3:1.objective measurements and will provide some We have now fairly good knowledge of the indication of the severity of the attack. An elecliberation of mediator substances from the trocardiogram and a chest radiograph should mast cell in the reaction with specific allergens also be available. Tachycardia is always a feature and about their possible significance in acute, of severe asthma and is related to the degree of asthmatic attacks. Yet we do not understand hypoxaemia (107). The average heart rate is what happens when the patient lapses into about [120][121][122][123][124][125][126][127][128][129][130] found an average status asthmaticus despite the use of the medi-rate of 126; Westerman (137) 139 with a range cation which in other situations has successfully from 110 to 180; Rees (107) 118, range 96-160. brought him relief Cooke et al. (25) found a heart rate above 90 in 87% of their patients and that 75% of the complications occurred in patients with a heart Objective assessment ^ , ,0•^ rate above 130. The treatment of severe asthma must reasonTwo important objective measurements that ably begin with an assessment of severity. Death any emergency ward s...

Severe Acute Asthma

“…The usefulness of theophylline in the treatment of status asthmaticus is less well docu mented. The bronchodilator effect of theophylline is dose dependent within a therapeutic range of 10-20 mg/1 [18], but weaker than that of (32-agonists [2], The additional positive inotropic effect on respira tory muscles and the pressure reduction in the pul monary circulation are beneficial effects in severe acute asthma [2,27]. There are considerable disadvan tages with theophylline because of its limited thera peutic range and concomitant side effects, such as nausea, vomiting, diarrhea, headaches, anxiety, and nervousness, often occurring at serum concentrations below 20 mg/1.…”

“…For the parenteral route, a dose of approximately 0.1-0.5 mg of the above-mentioned drugs should be given initially and, if ineffective, re peated after 30 min. The maintenance dose for intra venous infusion is 5-10 pg/min (maximal dose 25 pg/ min) [18,25]. Intravenous drug administration should be discontinued and switched to inhalative treatment as soon as possible [26].…”

“…p2-Agonists are effective by any route of administration (inhalation, oral, subcutaneous, or intravenous). However, even in severe acute asthma, inhalation is preferable because higher local bron chial concentrations can be reached with less systemic side effects [4,15,18]. p2-Receptor agonists in severe acute asthma should be given by nebulizer or occasionally by metered dose inhaler with a spacer device.…”

“…Compared to epinephrine or isoproterenol, which were used earlier, these drugs act specifically at the (32-receptor level and, therefore, have less cardiac side effects, while their bronchodilator effect is equipotent and lasts considerably longer [4,18]. A bronchodila tor effect can be expected within minutes which lasts for 4-6 h. Therefore, the use of these newer selective drugs is preferable to epinephrine with its potentially dangerous side effects [4,18]. Among the most widely used pi-agonists are fenoterol, salbutamol, and terbutaline, all of which can be regarded as clinically equipotent [19].…”

“…p2-Receptor agonists in severe acute asthma should be given by nebulizer or occasionally by metered dose inhaler with a spacer device. These techniques require minimal cooperation of the dyspneic patient, and large doses (up to 2.5-5 mg) of bronchodilator can easily be administered [4], IPPB inhalation has not been proven to be more effective than air-or oxygendriven jet nebulizers [15,18].…”