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Utility of Dexmedetomidine in Sedation for Radiofrequency Ablation of Atrial Fibrillation
LETTERS TO THE EDITOR Utility of Dexmedetomidine in Sedation for Radiofrequency Ablation of Atrial Fibrillation To the Editor: I read with great interest the article recently published in the Journal of PeriAnesthesia Nursing that examined the utility of using dexmedetomidine (DEX) as an adjunct to midazolam and fentanyl for procedural sedation and analgesia during radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF).1 With the view toward advancing knowledge about more effective medications for sedation in this challenging context, I offer the following insights for readers to consider regarding this study. Although it is recommended in guidelines for reporting observational research that matching should be taken into account in analysis, the statistical tests used to compare data between cases and matched controls did not account for the dependent nature of the data.1,2 Analysis that does not account for the dependent nature of matched data could result in an inaccurate strength of association between the dependent and independent variables or a change in the significance of the findings.3 For this reason, the use of the Wilcoxon rank sum test instead of the Wilcoxon signed ranks test could have led to errors in analysis of the important outcomes measured in this study.1,4 It cannot be inferred from the content of the article whether the appropriate statistical test for categorical variables (McNemar’s test) was used. Readers should note these potential limitations when considering the authors’ conclusion that the utility of DEX is limited in the context of RFCA of AF owing to a lack of significant reduction in consumption of midazolam and fentanyl.1 The nonsignificant findings from this small nonrandomized study should not discourage further research in this field. Instead, the results presented should be used to launch more rigorous examinations. An adequately powered randomized controlled trial is required to more precisely determine if adding DEX to midazolam and fentanyl is a more effective sedation regimen than standard practice during RFCA of AF.
Journal of PeriAnesthesia Nursing, Vol 28, No 5 (October), 2013: pp 257-259
Following are some important issues to consider in such an evaluation. First, a simple reduction in dose of midazolam and fentanyl is not an indicator that a sedation strategy incorporating DEX is more effective than standard practice. As the authors noted in their introduction, patient response to sedative medications is variable.1,5 Thus, more appropriate outcomes to measure in a study that aimed to compare the efficacy between the novel sedation strategy incorporating DEX and usual practice include patient satisfaction, interruptions to the procedure owing to ineffective sedation, and length of recovery.6,7 Second, for research to be translated to clinical practice, further evaluations of the use of DEX during electrophysiology should not compare monitored anesthesia care with cardiologistdirected nurse-administered sedation, unless of course the extra costs associated with monitored anesthesia care are considered when determining efficacy. Costs were not considered in the present study.1 Conducting a study that compares usual practice with a cardiologist-directed nurse-administered sedation strategy incorporating DEX would provide more useful insights for clinical practice; however, regardless of cost considerations, simply gaining access to monitored anesthesia care for sedation in the cardiac catheterization laboratory is difficult in many institutions around the world.8,9 Of note, for such research to be feasible, it would need to be a truly collaborative venture between the cardiologists, nurses, and anesthesiologists. An interdisciplinary approach, incorporating specialist knowledge from anesthesiologists for the development of protocols for medication titration and patient monitoring as well as comprehensive education programs, would ensure that cardiologists and nurses involved in the provision of patient care possess the necessary knowledge and skills to promptly detect clinical deterioration and effectively apply interventions to support or restore cardiac and respiratory function during DEX administration. The data reported in this study about the hemodynamic effects of DEX in patients undergoing RFCA of AF will considerably aid the development of such protocols and education programs to be used in future research.1 In this regard, I encourage the authors
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and other researchers to build on the results of this study and more rigorously examine the safety and effectiveness of DEX in the context of sedation during RFCA of AF. Indeed, my own recent research, in which the perceptions of nurses who are involved in administering sedation in Australian and New Zealand cardiac catheterization laboratories were explored, also indicated that such research is urgently required.6
ries: Results of an electronic survey. Aust Crit Care 2013: http://dx.doi.org/10.1016/j.aucc.2013.05.003. Accessed June 15, 2013. http://dx.doi.org/10.1016/j.jopan.2013.07.006
Reply: Utility of Dexmedetomidine in Sedation for Radiofrequency Ablation of Atrial Fibrillation
Sincerely, Aaron Conway, PhD, RN, BN (Hons) Research Fellow Institute of Health & Biomedical Innovation Queensland University of Technology Brisbane, Queensland, Australia
References 1. Dupanovic M, Lakkireddy D, Emert MP, Krebill R. Utility of dexmedetomidine in sedation for radiofrequency ablation of atrial fibrillation. J Perianesthesia Nurs. 2013;28: 144-150. 2. Vendenbroucke J, Von Elm E, Altman D, et al. Strengthening the reporting of observational studies in epidemiology (STROBE): Explanation and elaboration. Epidemiology. 2007; 18:805-835. 3. Stevens V, Brown JE. Comment: The relationship between inpatient fluoroquinolone use and Clostridium difficile–associated disease. Ann Pharmacother. 2010;44: 1855-1856. 4. Conway A, Page K, Rolley J, Fulbrook P, Thompson DR. Improving statistical analysis in matched case-control studies. Res Nurs Health. 2013;36:320-324. 5. Bhananker SM, Posner KL, Cheney FW, Caplan RA, Domino KB. Injury and liability associated with monitored anesthesia care: A closed claims analysis. Anesthesiology. 2006;104: 228-234. 6. Conway A, Rolley JX, Fulbrook P, Page K. Issues and challenges associated with nurse-administered procedural sedation and analgesia in the cardiac catheterisation laboratory: A qualitative study. J Clin Nurs 2013: http://dx.doi.org/10.1111/ jocn.12147. 7. Conway AW, Page K, Rolley JX, Worrall-Carter L. Nurseadministered procedural sedation and analgesia in the cardiac catheter laboratory: An integrative review. Int J Nurs Stud. 2011;48:1012-1023. 8. Gaitan BD, Trentman TL, Fassett SL, Mueller JT, Altemose GT. Sedation and analgesia in the cardiac electrophysiology laboratory: A national survey of electrophysiologists investigating the who, how, and why? J Cardiothorac Vasc Anesth. 2011;25:647-659. 9. Conway A, Rolley JX, Page K, Fulbrook P. Trends in nurse-administered procedural sedation and analgesia across Australian and New Zealand cardiac catheterisation laborato-
To the Editor: We would like to thank to Mr. Conway for his interest in our recent study.1,2 His comments highlight important considerations and reinforce necessity for further research in the field of procedural sedation for invasive electrophysiologic procedures. We would also like to provide clarifications about methods of the study and point to additional challenges in this field. Strict case-by-case matching was not enforced in the construction of the control group. The control group was selected to achieve similar univariate distributions in the treatment group with respect to age, height, and weight. Since strict case by case matching was not enforced, Wilcoxon rank sum test was used. No categorical variables were utilized in the analysis. Proportional differences in the need for cardioversion and the acquisition of sinus rhythm among patients who changed cardiac rhythms were evaluated with two sample proportion test. Of course, there is the need to study this topic using a more rigorous study design. Some of the factors listed in Mr. Conaway’s letter could not be accounted for in a case-controlled study and still remain to be evaluated. However, reduced doses of standard sedative drugs when combined with dexmedetomidine are important as a sign of efficacy of the substitute drug. Even a collection of trials may be needed to fully assess the advantages and disadvantages of supplementation of midazolam/fentanyl regimens using dexmedetomidine during radiofrequency ablation of atrial fibrillation. We would like to add that the number of procedures in adult electrophysiology has rapidly expanded over the past decade. These procedures
Journal of PeriAnesthesia Nursing, Vol 28, No 5 (October), 2013: pp 257-259
Following are some important issues to consider in such an evaluation. First, a simple reduction in dose of midazolam and fentanyl is not an indicator that a sedation strategy incorporating DEX is more effective than standard practice. As the authors noted in their introduction, patient response to sedative medications is variable.1,5 Thus, more appropriate outcomes to measure in a study that aimed to compare the efficacy between the novel sedation strategy incorporating DEX and usual practice include patient satisfaction, interruptions to the procedure owing to ineffective sedation, and length of recovery.6,7 Second, for research to be translated to clinical practice, further evaluations of the use of DEX during electrophysiology should not compare monitored anesthesia care with cardiologistdirected nurse-administered sedation, unless of course the extra costs associated with monitored anesthesia care are considered when determining efficacy. Costs were not considered in the present study.1 Conducting a study that compares usual practice with a cardiologist-directed nurse-administered sedation strategy incorporating DEX would provide more useful insights for clinical practice; however, regardless of cost considerations, simply gaining access to monitored anesthesia care for sedation in the cardiac catheterization laboratory is difficult in many institutions around the world.8,9 Of note, for such research to be feasible, it would need to be a truly collaborative venture between the cardiologists, nurses, and anesthesiologists. An interdisciplinary approach, incorporating specialist knowledge from anesthesiologists for the development of protocols for medication titration and patient monitoring as well as comprehensive education programs, would ensure that cardiologists and nurses involved in the provision of patient care possess the necessary knowledge and skills to promptly detect clinical deterioration and effectively apply interventions to support or restore cardiac and respiratory function during DEX administration. The data reported in this study about the hemodynamic effects of DEX in patients undergoing RFCA of AF will considerably aid the development of such protocols and education programs to be used in future research.1 In this regard, I encourage the authors
257
LETTERS TO THE EDITOR
258
and other researchers to build on the results of this study and more rigorously examine the safety and effectiveness of DEX in the context of sedation during RFCA of AF. Indeed, my own recent research, in which the perceptions of nurses who are involved in administering sedation in Australian and New Zealand cardiac catheterization laboratories were explored, also indicated that such research is urgently required.6
ries: Results of an electronic survey. Aust Crit Care 2013: http://dx.doi.org/10.1016/j.aucc.2013.05.003. Accessed June 15, 2013. http://dx.doi.org/10.1016/j.jopan.2013.07.006
Reply: Utility of Dexmedetomidine in Sedation for Radiofrequency Ablation of Atrial Fibrillation
Sincerely, Aaron Conway, PhD, RN, BN (Hons) Research Fellow Institute of Health & Biomedical Innovation Queensland University of Technology Brisbane, Queensland, Australia
References 1. Dupanovic M, Lakkireddy D, Emert MP, Krebill R. Utility of dexmedetomidine in sedation for radiofrequency ablation of atrial fibrillation. J Perianesthesia Nurs. 2013;28: 144-150. 2. Vendenbroucke J, Von Elm E, Altman D, et al. Strengthening the reporting of observational studies in epidemiology (STROBE): Explanation and elaboration. Epidemiology. 2007; 18:805-835. 3. Stevens V, Brown JE. Comment: The relationship between inpatient fluoroquinolone use and Clostridium difficile–associated disease. Ann Pharmacother. 2010;44: 1855-1856. 4. Conway A, Page K, Rolley J, Fulbrook P, Thompson DR. Improving statistical analysis in matched case-control studies. Res Nurs Health. 2013;36:320-324. 5. Bhananker SM, Posner KL, Cheney FW, Caplan RA, Domino KB. Injury and liability associated with monitored anesthesia care: A closed claims analysis. Anesthesiology. 2006;104: 228-234. 6. Conway A, Rolley JX, Fulbrook P, Page K. Issues and challenges associated with nurse-administered procedural sedation and analgesia in the cardiac catheterisation laboratory: A qualitative study. J Clin Nurs 2013: http://dx.doi.org/10.1111/ jocn.12147. 7. Conway AW, Page K, Rolley JX, Worrall-Carter L. Nurseadministered procedural sedation and analgesia in the cardiac catheter laboratory: An integrative review. Int J Nurs Stud. 2011;48:1012-1023. 8. Gaitan BD, Trentman TL, Fassett SL, Mueller JT, Altemose GT. Sedation and analgesia in the cardiac electrophysiology laboratory: A national survey of electrophysiologists investigating the who, how, and why? J Cardiothorac Vasc Anesth. 2011;25:647-659. 9. Conway A, Rolley JX, Page K, Fulbrook P. Trends in nurse-administered procedural sedation and analgesia across Australian and New Zealand cardiac catheterisation laborato-
To the Editor: We would like to thank to Mr. Conway for his interest in our recent study.1,2 His comments highlight important considerations and reinforce necessity for further research in the field of procedural sedation for invasive electrophysiologic procedures. We would also like to provide clarifications about methods of the study and point to additional challenges in this field. Strict case-by-case matching was not enforced in the construction of the control group. The control group was selected to achieve similar univariate distributions in the treatment group with respect to age, height, and weight. Since strict case by case matching was not enforced, Wilcoxon rank sum test was used. No categorical variables were utilized in the analysis. Proportional differences in the need for cardioversion and the acquisition of sinus rhythm among patients who changed cardiac rhythms were evaluated with two sample proportion test. Of course, there is the need to study this topic using a more rigorous study design. Some of the factors listed in Mr. Conaway’s letter could not be accounted for in a case-controlled study and still remain to be evaluated. However, reduced doses of standard sedative drugs when combined with dexmedetomidine are important as a sign of efficacy of the substitute drug. Even a collection of trials may be needed to fully assess the advantages and disadvantages of supplementation of midazolam/fentanyl regimens using dexmedetomidine during radiofrequency ablation of atrial fibrillation. We would like to add that the number of procedures in adult electrophysiology has rapidly expanded over the past decade. These procedures