QA Clearinghouse. Quality Assurance in a Clinical. Pharmacy Program. During the past decade the role of hospital pharmacies in providing patient care ...
QA Clearinghouse
Quality Assurance in a Clinical Pharmacy Prog ram During the past decade the role of hospital pharmacies in providing patient care services has expanded dram atically . Pharmacists no longer simply manage pharmacological products; they now apply pharmaco kinetic principles to monitor and adjust dosage regimens, provide comprehen sive drug information to ot her health care professionals, participate in nutrition support teams, and counsel patients about thei r drug therapy . This expanded role has dictated a pa rallel expansion in the scope and so phistication of pharmacy quality assurance (QA) activities. Developin g effective QA programs for these new pharmacy services and functions has not been easy, however, because performance stand ards are as yet undetermined and because patient outcomes can sel dom be directly attributed to pharmacy interve ntion.1·1 Nevertheless , pharmacy QA programs have been made essential by the advent of the prospective rate of payment system for Medicare reimburse ment, which has caused many hospitals to rev iew the cost effectiveness and quality of al l patient services. 3 At Shands Hospital , a 476-bed acute care teaching facility in Gainesville. Florida, the pharmacy department performed a QA study to evaluate the impact of a clinical pharmacokineti c service. the Drug Therapy Co nsult Service ( DTCS).
on patient care and on patient costs. DTCS and aminoglycoside antibiotic monitoring. The DTCS was establ ished in 1982 to assist physicians in providing optimal drug treatment fo r patients. The DTCS is available for consultation on patient drug regimens and as an education al resource for the medical and nursin g staffs and for medical and pharmacy students. One activi ty in wh ich the DTCS has been involved is the monitoring of aminoglycoside antibiotic doses. Aminoglycoside antibiotics are a class of drugs often focused on in utilization review studies because of their widespread use, cost, and potential for producing ototoxicity and nephrotoxicity if given in inappropriate doses. H These antibiotics, which are used to treat severe gram-negative infections. have an extremely narrow therapeutic range . Des pite some controversy surrounding the relative co ntributions of elevated peak and trough seru m concentrations to aminoglycoside antibiotic toxicity, maintatntng serum aminoglycoside levels (SALs) within the des ired range is the accepted method for ensuring therapeutic concentrations of these medications and for minim izing toxicity.~-~> For SAL monitoring and dosage adjustment to be effective, the a ntibiotic dose must be administered at t he scheduled time. the SAL must be obtained at an appropriate time during the dosing interval, the laboratory analysis of the se rum sa mpk
must be accurate!, and clinicians must know the times of drug administration and ser um sampling to determine if reported results are valid. Results of pre·.:ious studi-:s suggest that this mon itoring tec hnique has been inappropriately utilized. Matzke et al reported that SALs were ordered for only 21 (6.8 %) patien ts in a study group of 309 patients receiving aminoglycoside antibiotics, and when SALs were monitored, the results were correctly utilized only 41% of the ti me.: Flynn et al found that only -+9'0 of the:: SAL determinatio ns they studied were valid and on ly 220:0 •vere used to make app ropriate therapeutic dosage adjustments.s An evaluation of SAL monitoring. The effectiveness of the Shands • Hospital DTCS SAL monitoring service was evaluated in a retrospective study of the medical records of 90 patients who received gentamincin or tobramycin and had SALs monitored in November and Decem ber 1982 . Fifty-five (61 %) of these patients had their SALs monitored by the DTCS: the rem aining 35 (39%) had SALs monitored by a physician. From this group of 90, a systematic sample of 34 patients was chosen: 18 were DTCS monitored and 16 were physicia n monitored . To det ermine if SALs v..-ere obtained at the appropriate t ime during the dose interval and if the SAL information was used to make appropriate dosage adjustments, the percentage of wasted S.-\Ls and the
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percentage of therapeutic nontox!c serum le vels res ulting from SAL-indicated dosage :.tdjustments were analyzed for the DTCS-monitored and phys ician-monitored g roups. The analysis was performed by a hospital pharmacy resi dent. SAL moni to ring criteria (see Figure 1, page 88) adapted from a criteria set develo ped ea rlier by the institution's infectious disease physicians and from literature recommendations were used to determine if SALs had been obtained appropriately. Therapeutic nontoxic serum ·els were defined as peaks of 4-10 mcg j ml and troughs less than 2 m cgj m1.~· 6 ·d No attempt was made to stratify patients' clinical conditions or to measure outcomes. A larger sample and a homogeneous patient population would have been requi·red to make valid comparisons of p atient outcomes. Results. Compliunce with the SAL monitoring cri teria was determ ined for the DTCS-monitored and physician-monitored patient groups, and a one-tailed chi square analysis was used to test for significant difference. Ninety-seven percent of the DTCS-ordered SALs were obtained appropriately; 70% of the physici an -ordered SALs were obtained app ropria te ly. This difference was signific ant at the .001 level. The d isparity between approp riateness of DTCS-obtained and ,...t, ysician-obtained SALs may have _ .~n even greater because only 22% of the physicia n- ob tai ned SAL samp les were properly labeled with the actual sampling time. Eighty83
t nr~~ percent o f the DTCS-obt:lir.ed S.-\ Ls were properly labeled tp
