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LETTERS TO THE EDITOR

Clinical Guidelines

Richard C. Prielipp, MD^*, and John F. Butterworth, MD

Departments of *Critical Care and Cardiothoracic Anesthesia Wake Forest University School of Medicine Winston-Salem, NC 27157-1009

Djaiani et al. (1) collated retrospective data on 10 patients with sickle cell trait undergoing coronary artery bypass graft (CABG) surgery, for whom care was guided by an institutional "fast-track" anesthesia protocol. Our attention was drawn to Table 5, where the authors advance "proposed guidelines for perioperative management of patients with sickle cell disorders undergoing CABG surgery" (1).

The word "guideline" has acquired specific meaning, with customary requirements, much like use of the word "significant" in scientific discussion. Clinical guidelines have taken on a specific form since 1979 when the Canadian Task Force on the Periodic Health Examination (2) generated "levels of evidence" for ranking the validity of evidence and then tied them as grades of recommendation to the advice reported. This process has grown increasingly sophisticated (3), with published guidelines having a common, well defined, vigorous, scaled evaluation of all external scientific evidence and a qualitative grade for each proposed guideline or recommendation. A sample of a condensed scale for evaluating literature is reproduced in Table 1 below (see Reference 4 for full details) (2,4).

References

1. Djaiani GN, Cheng DCH, Carroll JA, et al. Fast-track cardiac anesthesia in patients with sickle cell abnormalities. Anesth Analg 1999;89:598–603.[Abstract/Free Full Text]
2. Canadian Task Force on the Periodic Health Examination.The periodic health examination. Can Med Assoc J 1979;121:1193–254.[Medline]
3. Sackett DL. Rules of evidence and clinical recommendations on use of antithrombotic agents. Chest 1989;95:2S–4S.[Free Full Text]
4. Clinical evidence. BMJ Publishing Group. Available at http://www.evidence.org. Accessed September 15, 1999.

Response

Department of Anesthesia Toronto General Hospital Toronto, Ontario M5G 2C4, Canada

Thank you for an opportunity to respond to the letter by Professors Prielipp and Butterworth referring to Table 5 in our recent article (1). In their letter, the authors caution the readers of Anesthesia & Analgesia that our proposed guidelines for perioperative management of patients with sickle cell disorders undergoing coronary artery bypass graft (CABG) surgery (1) should not be regarded as clinical guidelines because they have not undergone the customary scrutinized evaluation and confirmation in a prospective, randomized manner.

We very much appreciate the authors comments and share their concerns that the standards of practice of medicine and development of clinical guidelines and protocols should be derived from the evidence-based delivery of health care. There is no doubt that evidence-based medicine is becoming a major part of our routine clinical practice; however, hard evidence to either support or refute the treatment of patients with sickle cell hemoglobinopathies undergoing cardiac surgery is simply not available. We emphasized in our paper that the current published literature on the above subject is limited to either single or serial case report studies, and most of them are confined to children undergoing correction of congenital heart defects. Where do we go from here?

We conducted this cohort retrospective study to elicit if fast-track anesthesia (FTA) can be safely applied to patients with sickle cell trait undergoing CABG surgery. The results of our study confirmed that this subgroup of patients can be managed safely with the application of FTA protocol. We accept the criticism that our study was not a prospective, randomized, controlled trial (RCT); however, even the most rigorous RCT may raise the issue of its internal and external validity with potential problems of reproducibility. There is a huge variability in the acceptance and application of clinical guidelines even with less presumptuous topics between different countries, states, and institutions; furthermore, what seems to be an accepted and indisputable technique today may become an inappropriate or obscure practice tomorrow.

The other difficulty is to apply the results from the study groups of patients to the individual situation. It is clear that clinical guidelines will always require modification in the light of the clinician’s experience and the needs of each patient. We consolidated all the up-to-date information and presented it as short table of reference to guide anesthesiologists who encounter this specific problem. Our recommendations were based on currently available evidence of safe and nonambiguous practice and our local expertise and should be used as an aid to clinical decision making. It is evident that the clinicians should always use their professional judgement to apply these guidelines to the individual.

Whether we await the multicenter, adequately powered, prospective, randomized clinical trials which may or may not test each of our proposed recommendations or offer the practicing anesthesiologists a guide for the management of sickle cell patients undergoing cardiac surgery today, is a matter of conjecture. We would like to leave it to the readers’ discretion.

References

1. Djaiani GN, Cheng DCH, Carroll JA, et al. Fast-track cardiac anesthesia in patients with sickle cell abnormalities. Anesth Analg 1999;89:598–603.

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a colleague Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by Prielipp, R. C. Articles by Cheng, D. C. H. Search for Related Content PubMed PubMed Citation Articles by Prielipp, R. C. Articles by Cheng, D. C. H.