Cardiotoxicity of parenteral terbutaline in the treatment of status asthmaticus and suggested monitoring guidelines

Introduction: During a nine month period, we proapectivery evaluated aU patients admitted to the Pediatnc Intensive Care Umt for status aslhmaticus who were treated with parenteral Terbutaline for evidence of tnyocanual toxicity. Our goals were to determine the safety of this medication as well as establish monitoring guidelines for its use. Methods: Fifteen patients aitnitlnd to the PICU with status asthmalicus were enrolled in the study with an age range of 11 months to 16 years (mean 8.6 years.) Indications for enrollment included worsening respiratory failure despite standard treatment with continuous Albuterol via nebulizer and parenteral steroids. Baseline electrocardiograms (ECG) and creatine phosphokmase (CPK) levels with MB fractions were drawn prior to starting Terbutaline. ECG 's were performed daily while on therapy and serial CPK-MB levels were drawn every eight hours on the first day of treatment and then once per day. HR. BP. SpO PaO and FIO, were monitored throughout the treatment course. FlO₂/PaO, ratios were calculated to assess for ghmge in veotilatioo/periuswo and oxygénation. Rauilr The following abnonnalitiewere found: I ) Two patients developed ECG changes cnrrcitfing of T wave inversion which resolved off therapy. 2) One patient experienced multiple P VC 's with no ischémie changes; 3) One patient developed ectopic trial tachycardia which resolved off therapy, 4) One patient exhibited ST changes on ECG that preceded therapy. 5) FlO₂/PaO, ratios were unchanged or decreased from baseline while on Terbutahne; 6) Four of the six mechanically ventilated patients had marked elevation in CPK levels (>2000 IU/L). but none of the fifteen patients had statistically significant elevations of MB isoenzymes. Conclusions: The use of IV Terbutaline in the treatment of status asmmaticus was associated with ECG changes consistent with myocardial TP(with no change in MB fractions) in two of our patients, and two patients developed rhythm disturbanceNormal or decreased FlO₂/PaO, ratios suggest that hypoxia was not the etiology for the changes. If larger studies confirm our findings, appropriate guidelines for patients treated with IV Terbutaline would be: I) Baseline ECG's and CPK-MB levels prior to therapy. 2) Dairy ECG's white on treatment; 3) Serial CPK-MB levels if tbe ECG's are suggestive of myocardial ischemia.