[Perioperative evaluation of a kit for simplified measurement of blood theophylline concentration (Accumeter Theophylline)].

Background: We investigated the perioperative usefulness of a kit for simplified measurement of blood theophylline concentration (BTC), Accumeter theophylline (Nikken Chemicals Co.) in asthmatic patients.

Methods: Study 1) BTCs were measured by Accumeter at the beginning of surgery in asthmatic patients who had been medicated with oral theophylline. Study 2) BTCs were corrected during anesthesia in asthmatic patients who showed lower BTCs (<8 microg x g ml(-1)) at the beginning of surgery. Study 3) Theophylline was administered to asthmatic patients who had not been medicated with theophylline, and calculated and measured BTCs were compared.

Results: Study 1) Measured BTC at the begin- ning of surgery was 8.2 +/- 3.1 microg x ml(-1) (mean +/- SD), and 14 of 31 patients (45%) showed lower BTC. Patients who smoked showed a significantly lower BTC than that of non-smoking patients (P=0.04). Study 2) Five of 10 patients showed lower BTC at the beginning of surgery, but BTC had increased significantly at the end of surgery after i.v. administration of theophylline. Study 3) There was no significant linear correlation between calculated and measure BTCs after i.v. administration of theophylline (R2=0.25, n=10). Although the mean was near zero (0.05) by limits of agreement, 2 SD was large (2.53). There was no patient who showed wheezing during the study.

Conclusions: It is important to monitor BTCs perioperatively in asthmatic patients, and Accumeter theophylline is a simple and useful device for management of BTC.