CORRESPONDENCE

To the Editor: Our study was designed to evaluate prospectively the use

of the peak flow meter to predict need for hospital admis- sion. It is imperative that any such study use prespecified admission criteria, a fixed treatment protocol, and most im- portantly blinded pulmonary function measurements to minimize biases and maximize control over other variableK

Our admission criteria are representative of the current phi losophy in the emergency managemen t of asthma. These criteria are not perfect. After all, the purposes of our study and others like Nowak 's I'2 have been to improve these admission criteria. We strongly believe that three emergency department visits for acute asthma within seven days justifies hospital admission. This occurrence is a clear sign that the asthma is out of control. In these circum- stances one should suspect inadequate medical therapy and/ or re-exposure to precipitating factors. Both these factors can be remedied by competent inpatient treatment. I refer Dr. Nowak to our article, "Use of Peak Expiratory Flow Rates to Eliminate Unnecessary Arterial Blood Gases in Acute Asthma" (11:70-73, February 1982) for the results of our arterial gas analysis.

I certainly agree with Dr. Nowak that close patient follow up is desirable in those discharged. Each discharged patient was given written instructions on his therapy which was to continue for at least five days. Furthermore each patient Was given an appointment for a special clinic in the pulmo- nary medicine department, but only a handful chose to keep

this appointment. Perhaps a phone call would have been more successful. Most of the patients use our hospital ex- clusively, but we realize that a few may have gone else- where.

Despite admitted design flaws in our study, we are confi- dent that its conclusions are justified. Early pulmonary function testing alone is not a useful predictor of need for hospital admission in acute asthma. We agree with others that low airflow rates present before treatment and a small response to initial therapy are signs of severe asthma, but we feel they are not always signs of irreversible asthma. Furthermore simple pu lmonary funct ions are useful in acute asthma for the following reasons: to screen for pa- tients at risk of severe arterial blood gas abnormalities; to evaluate the severity of airflow obstruction initially and the response to therapy; to facilitate transfer of care between physicians; and possibly to predict relapse after all treat- ment.

Thomas G. Martin, MD Portland, OR

1. Nowak RM, Gordon KR, Wroblewski DA, et al: Spirometric evaluation of acute bronchial asthma. JACEP 8:9-12, 1979.

2. Nowak RM, Pensler MI, Sarkar DD, et al: Comparison of peak expiratory flow and FEVx admission criteria for acute bronchial asthma. Ann Emerg Med 11:64-69, 1982.

98t126 Annals of Emergency Medicine 12:2 February 1983