Acute severe asthma: Differences in therapies and outcomes among pediatric intensive care units* Joan S. Roberts, MD; Susan L. Bratton, MD, MPH; Thomas V. Brogan, MD A sthma remains the most com- mon cause of hospitalization among children (1), and death attributable to asthma has in- creased (2). Status asthmaticus is a com- mon diagnosis for admission to the pedi- atric intensive care unit (PICU). The pharmacologic components of status asthmaticus therapy include  2 -agonists, corticosteroids, and anticholinergic agents. Invasive interventions including mechanical ventilation, invasive moni- toring of blood pressure, and central ve- nous pressure also are used in more se- vere cases. Extraordinary therapies such as inhalation of volatile anesthetic gases and extracorporeal life support have been used to treat life-threatening asthma that failed to improve or worsened despite conventional therapy (3). Children require mechanical ventila- tion for asthma when they have profound hypoxemia, life-threatening respiratory muscle fatigue, or altered mental status. However, high airway pressure, baro- trauma, and patient-ventilator dyssyn- chrony complicate mechanical ventila- tion in patients with asthma (4). Although potentially life saving, use of mechanical ventilation during an asthma exacerbation is associated with an in- creased risk of death from asthma (5– 6). Therapy for status asthmaticus tradi- tionally has been difficult to study in chil- dren because of the subjective element of patient assessment. Severely ill children frequently are unable to perform pulmo- nary function tests. We hypothesized that tolerance of severe dyspnea and hypercar- bia varies widely and that use of mechan- ical ventilation also would vary among intensive care providers. Recently, the Pediatric Intensive Care Evaluations (PICUEs), a large, multiple-center PICU database, became available to researchers (7). This provided an opportunity for a large-scale examination of the use of me- chanical ventilation and invasive vascular monitoring in children with severe asthma. It also enabled us to compare outcomes between centers with high and low use of mechanical ventilation for asthma. MATERIALS AND METHODS We requested the records for all children in the PICUEs master dataset with a primary diagnosis of asthma. PICUEs is a system for monitoring performance of PICUs that pro- vides standardized mortality ratios, standard- ized length of stay, and efficiency rates (7). The PICUEs dataset contained approximately 20,000 records from 14 centers at the time of our request. Participation is voluntary, and centers pay a fee for standardized reports. Spe- cific centers are not identified in the dataset. PICUEs provided us information that was vol- untarily submitted by nine of the participating hospitals for this report regarding character- istics of the individual PICUs. The average number of PICU beds was 18 (range, 10 –36). *See also p. 713. From the Department of Pediatrics (JSR, TVB), University of Washington School of Medicine, Chil- dren’s Hospital and Regional Medical Center, Seattle, WA; and the Department of Pediatrics (SLB), University of Michigan School of Medicine/Mott Children’s Hos- pital, Ann Arbor, MI. Copyright © 2002 by Lippincott Williams & Wilkins Objective: To determine differences in therapies and outcomes among pediatric intensive care units for patients with acute severe asthma. Design: Retrospective cohort study. Setting: Eleven pediatric intensive care units participating in the Pediatric Intensive Care Evaluations. Patients: Patients were 1528 children with a primary diagnosis of asthma. Interventions: None. Measurements and Main Results: We studied severity of ill- ness, length of stay, and use of invasive interventions. The pa- tients at the centers had similar median physiologic measures of illness and Pediatric Risk of Mortality III scores. The patients received a wide range of invasive interventions depending on institution, including mechanical ventilation (3% to 47%), arterial catheter placement (4% to 46%), central venous catheter (2% to 51%), and determination of a blood gas (24% to 70%). At insti- tutions where mechanical ventilation was used more commonly (>20%, high use), intensive care and hospital stays were longer for asthmatic patients regardless of mechanical ventilation re- quirement compared with centers with lower use of mechanical ventilation. The status of “high-use center” was an independent predictor for intensive care stay (p  .005) and hospital length of stay (p  .017) as well as duration of mechanical ventilation (p  .014) after adjustment for age, degree of hypercarbia, maximal respiratory rate, use of an arterial catheter, and Pediatric Risk of Mortality III scores among ventilated children. Conclusions: We found that use of invasive interventions in- cluding mechanical ventilation and vascular monitoring varied greatly by institution. Centers with higher use of mechanical ventilation had longer median intensive care stay and hospital stays. Pediatric asthma management for acute severe asthma may be improved by clear elucidation of the institutional practices where fewer invasive interventions were used to achieve better outcomes. (Crit Care Med 2002; 30:581–585) KEY WORDS: asthma; intensive care unit pediatric; respiration artificial 581 Crit Care Med 2002 Vol. 30, No. 3