Study design
The development of the guide for the continuity of care in perioperative medication management was based on a literature search and an external review by an expert committee. The guide was validated through a prospective, noninterventional cohort study. The flow of the study process is illustrated in Fig. 1.
Development of the guide
The guide was formulated by an expert pharmacist (CM) by systematically reviewing the available evidence for each medication class, based on the Anatomical Therapeutic Chemical (ATC) classification system developed by the European Pharmaceutical Market Research Association [15]. It includes the most consumed ATC pharmacological subgroups according to data for the year 2014 from the Ministry of Health, Social Services and Equality of Spain [16].
Recommendations were based on three concepts: the pharmacokinetics of the drug, the effect of withdrawing the medication on the primary disease, and the effect of the medicine on the perioperative risk, including potential interactions with anesthetic agents.
For the literature search, a consistent process was applied, based on:
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Drug information (technical data sheet).
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Micromedex®. Provides summaries and detailed monographs for drugs, diseases, alternative medicine, toxicological managements, reproductive risks, and emergency care. It includes the following drug information databases:
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DRUGDEX® system. Dosage, pharmacokinetics, cautions, interactions, clinical applications, and comparative drug efficacy.
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MARTINDALE. Electronic version of the Martindale textbook published by the Royal Pharmaceutical Society of Great Britain. Offers extensive information on international drug products. Especially useful when searching for European drugs, and can be searched by brand name or generic name.
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Alternative medicine. Includes monographs on herbal, vitamin, mineral, and other dietary supplements, based on scientific evidence as well as historical and common uses.
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UptoDate®. An evidence-based, physician-authored clinical decision support resource that clinicians trust to make the right point-of-care decisions. Muluk and Macpherson provide an overview of preoperative patient assessment as well as details about the perioperative management of specific medications [12].
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PubMed®. Online database of biomedical journal citations and abstracts. The search strategy was similar to that applied by Lievanos Rojas in his thesis Perioperative management of chronic medications in orthopaedic surgery. A systematic review of the literature [17].
Finally, an external multidisciplinary review of the guide was performed by members of the Pharmacy and Therapeutics Committee at the Hospital General Universitario de Elche, including surgical specialists and physicians from the Department of Anesthesiology, who contributed their experience in clinical practice.
Validation of the guide
The guide was validated by performing an interobserver variability study.
Participants
An expert pharmacist (CM) with 15 years of experience in the pharmacotherapeutic validation of medical orders was responsible for developing the guideline, and acted as the gold standard. She determined the correct action to perform regarding usual chronic treatments in the perioperative environment according to the clinical status of the patient.
The observers comprised eight pharmacists with different levels of professional experience who were working in the same hospital. There were three staff pharmacists, all of whom had clinical and pharmacological knowledge and a wide range of experience in the pharmacotherapeutic validation of medical orders; five resident pharmacists, two of whom were residents in their first year and thus had little knowledge of the practical application of drugs; and three other resident pharmacists in their second or third year of residency, who had more experience in validating the pharmacotherapeutic profiles of patients.
Training course
The course was given by the expert (CM). The concepts covered in the session addressed the following five questions:
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Why was the guide created? She explained that the purpose of the guide was to ensure the continuity of pharmacotherapeutic information, reduce variability in clinical practice, exceed the needs of the patient at all times during the perioperative period by improving safety, and improve the efficiency of the medication utilization process.
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How is the guide structured? She presented a brief summary of the format of the guide, including its structure according to the ATC classification, as well as the benefits and risks of continuing or discontinuing medication in the perioperative environment.
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How are the chronic medications grouped according to perioperative recommendations? She described simple concepts for the following situations:
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Drugs that can increase morbidity if they are discontinued abruptly. Their use should continue in the perioperative period, or the treatment can be adjusted if possible.
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3.2.
Drugs that increase the risk of anesthetic medications or complications during surgery and which are not essential in the short term. These drugs should be suspended during the perioperative period.
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Drugs that do not belong to any of the previous groups. These may be suspended or continued according to clinical criteria.
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What basic pharmacological concepts do we need to know? She gave participants a brief overview of the most relevant drug interactions as well as descriptions of metabolic processes and the elimination of drugs and their metabolites, and she discussed how these can be altered in the perioperative period.
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How should I act if I have any doubt? She stressed the importance of agreeing with clinic staff (either the orthopedic surgeon responsible for the patient or another relevant medical specialist) on the action to be taken in the event of clinical instability of the patient, or if there is doubt about the typical chronic treatment.
Source of patients
Patients admitted to an orthopedic surgery unit in a Spanish tertiary 450-bed hospital from August 1 to September 1, 2016, were included in the validation study. The number of chronic medications required for the study was calculated based on the sample size required to detect a kappa value that was significantly different from zero with 90% power. We aimed for a power of 90% in a two-tailed test for a kappa value of at least 0.6, where we estimated that the guidelines would have greater than 90% concordance with the views of the expert pharmacist. The calculated value was based on assessments of over 30 drugs [18]. Therefore, 140 drugs were analyzed in 20 patients (seven drugs per patient).
Study procedure
Each observer (i.e., pharmacist) received a dossier containing drug therapy and clinical information about each of the 20 patients to whom the guide was to be applied. The information about the patients comprised the following: the patient’s ID number (1–20), age, sex, personal history, diagnosis-related drugs (DRGs), date of surgical intervention, and chronic treatment. The form included specific instructions that had to be marked with an X depending on whether the decision was made to continue (C) or suspend (S) treatment for the patient according to the guide for the continuity of care in perioperative medication management and the clinical information about the patient.
Patient treatments were reviewed blindly and independently by the eight pharmacists and compared with the gold standard (CM).
Statistical analysis
Statistical analyses were carried out using the software SPSS for Windows 20.0 (IBM SPSS). Cohen’s kappa, with a confidence interval (CI) of 95%, was used to analyze the concordance between each observer and the expert and between the eight observers. The degree of concordance was expressed as a numerical value of k, which ranged from 0.0, indicating absolute discordance, to 1.0, indicating perfect concordance. A value of > 0.61 indicated that the agreement was good [19]. For each item in the scale, the percent agreement was calculated as the number of times that the raters agreed on a rating (continue/discontinue) divided by the total number of ratings.