Sedation with dexmedetomidine in post-cardiac surgery patients: practical considerations
Wan-Jie Gu, Graduate School of Guangxi Medical University, Nanning 530021, Guangxi,China
1 October 2012
To the Editor:
I read with interest the paper published in Critical Care by Lin and colleagues, who investigated the effectiveness and safety of dexmedetomidine as a sedative agent in post-cardiac surgery patients [1]. I congratulate the authors on their interesting and important work on this topic. Nevertheless, some concerns need to be discussed.
First, inclusion/exclusion criteria: a) In Materials and methods, only randomized controlled trial, non-random controlled trial or cohort study was included this meta-analysis. But a case-control study [2] was also included in Table 2. b) Why exclude the non-English language studies? Though I appreciate the difficulty of assessing a manuscript written in a language you do not speak or write, there is no scientific reason for excluding such manuscripts. It was possible that the exclusion of non-English language studies may lead to bias in effect size. The authors should give a more detailed description of the inclusion/exclusion criteria.
Second, outcomes: a) The meta-analysis indicated that there were no significant differences in intensive care unit stay, hospital stay, and morphine equivalents. In fact, these results are not conclusive inasmuch as they are not adequately powered to examine the effect of dexmedetomidine on these endpoints. They were not regarded as the primary outcome and were the only clinically significant endpoints consistently reported in some of the studies included in this meta-analysis. b) Although many outcomes were assessed, there are other equally important variables that can determine the use of dexmedetomidine as a sedative agent (all-cause mortality, myocardial infarction or ischemia, etc.).
Third, the real question is why dexmedetomidine is not the ubiquitous sedative agent in post-cardiac surgery patients if it is so good? However, there are many other reasons why it is not widely used and none of these are presented in this review. First, there is no mention of the cost of an ampoule of dexmedetomidine versus other medications. Most institutions cannot split an ampoule of dexmedetomidine among patients and in fact, restrict the use of this medication altogether in the hospital because it is very expensive, far more expensive than other medications. That being the case, how do the authors justify dexmedetomidine? Second, these comparative studies that are cited in the meta-analysis are flawed. Most of them were non-randomized and poor-quality.
In conclusion, the use of dexmedetomidine may need practical considerations in post-cardiac surgery patients.
References
1. Yiyun Lin, Bin He, Jian Chen, Zhinong Wang: Can dexmedetomidine be a safe and efficacious sedative agent in post-cardiac surgery patients: a meta-analysis? Critical Care 2012, 16:R169.
2. Reichert MG, Jones WA, Royster RL, Slaughter TF, Kon ND, Kincaid EH: Effect of a dexmedetomidine substitution during a nationwide propofol shortage in patients undergoing coronary artery bypass graft surgery. Pharmacotherapy 2011, 31:673-677.
Competing interests
The author declares no conflicts of interest.
Authors¿ response
Yiyun Lin, Department of Cardiothoracic Surgery, Changzheng Hospital, the Second Military Medical University, Shanghai, China
5 November 2012
We thank Gu for his comments. Indeed, our results indicate that sedation with dexmedetomidine is associated with shorter length of mechanical ventilation and lower risk of delirium following cardiac surgery. Further, dexmedetomidine may decrease the risk of postoperative ventricular tachycardia and hyperglycemia, and not increase length of hospital stay and mortality at hospital discharge. [1] Thus, we hypothesized that dexmedetomidine would be a safe and efficacious sedative agent in cardiac surgical patients.
Please note that we have listed several limitations of this study at the end of the manuscript. [1] First, different goals of ideal sedation, and different diagnosis method may not result in the widespread utilization of our results. Second, considering the high cost of dexmedetomidine, additional cost-effective studies are warranted. To enable adequate cost comparisons, proper drug-related cost must be well-defined during clinical study designs, which is generally not the case. However, Gu raised an interesting concern with regard to the lack of high quality randomized controlled studies, which could underscore the value of adequate patient selection for the safe use of dexmedetomidine following cardiac surgery.
Reference
1. Yiyun Lin, Bin He, Jian Chen, Zhinong Wang: Can dexmedetomidine be a safe and efficacious sedative agent in post-cardiac surgery patients: a meta-analysis? Critical Care 2012, 16:R169.
Critical Care
Sedation with dexmedetomidine in post-cardiac surgery patients: practical considerations
1 October 2012
To the Editor: I read with interest the paper published in Critical Care by Lin and colleagues, who investigated the effectiveness and safety of dexmedetomidine as a sedative agent in post-cardiac surgery patients [1]. I congratulate the authors on their interesting and important work on this topic. Nevertheless, some concerns need to be discussed. First, inclusion/exclusion criteria: a) In Materials and methods, only randomized controlled trial, non-random controlled trial or cohort study was included this meta-analysis. But a case-control study [2] was also included in Table 2. b) Why exclude the non-English language studies? Though I appreciate the difficulty of assessing a manuscript written in a language you do not speak or write, there is no scientific reason for excluding such manuscripts. It was possible that the exclusion of non-English language studies may lead to bias in effect size. The authors should give a more detailed description of the inclusion/exclusion criteria. Second, outcomes: a) The meta-analysis indicated that there were no significant differences in intensive care unit stay, hospital stay, and morphine equivalents. In fact, these results are not conclusive inasmuch as they are not adequately powered to examine the effect of dexmedetomidine on these endpoints. They were not regarded as the primary outcome and were the only clinically significant endpoints consistently reported in some of the studies included in this meta-analysis. b) Although many outcomes were assessed, there are other equally important variables that can determine the use of dexmedetomidine as a sedative agent (all-cause mortality, myocardial infarction or ischemia, etc.). Third, the real question is why dexmedetomidine is not the ubiquitous sedative agent in post-cardiac surgery patients if it is so good? However, there are many other reasons why it is not widely used and none of these are presented in this review. First, there is no mention of the cost of an ampoule of dexmedetomidine versus other medications. Most institutions cannot split an ampoule of dexmedetomidine among patients and in fact, restrict the use of this medication altogether in the hospital because it is very expensive, far more expensive than other medications. That being the case, how do the authors justify dexmedetomidine? Second, these comparative studies that are cited in the meta-analysis are flawed. Most of them were non-randomized and poor-quality. In conclusion, the use of dexmedetomidine may need practical considerations in post-cardiac surgery patients. References 1. Yiyun Lin, Bin He, Jian Chen, Zhinong Wang: Can dexmedetomidine be a safe and efficacious sedative agent in post-cardiac surgery patients: a meta-analysis? Critical Care 2012, 16:R169. 2. Reichert MG, Jones WA, Royster RL, Slaughter TF, Kon ND, Kincaid EH: Effect of a dexmedetomidine substitution during a nationwide propofol shortage in patients undergoing coronary artery bypass graft surgery. Pharmacotherapy 2011, 31:673-677.
Competing interests
The author declares no conflicts of interest.
Authors¿ response
5 November 2012
We thank Gu for his comments. Indeed, our results indicate that sedation with dexmedetomidine is associated with shorter length of mechanical ventilation and lower risk of delirium following cardiac surgery. Further, dexmedetomidine may decrease the risk of postoperative ventricular tachycardia and hyperglycemia, and not increase length of hospital stay and mortality at hospital discharge. [1] Thus, we hypothesized that dexmedetomidine would be a safe and efficacious sedative agent in cardiac surgical patients.
Please note that we have listed several limitations of this study at the end of the manuscript. [1] First, different goals of ideal sedation, and different diagnosis method may not result in the widespread utilization of our results. Second, considering the high cost of dexmedetomidine, additional cost-effective studies are warranted. To enable adequate cost comparisons, proper drug-related cost must be well-defined during clinical study designs, which is generally not the case. However, Gu raised an interesting concern with regard to the lack of high quality randomized controlled studies, which could underscore the value of adequate patient selection for the safe use of dexmedetomidine following cardiac surgery.
Reference
1. Yiyun Lin, Bin He, Jian Chen, Zhinong Wang: Can dexmedetomidine be a safe and efficacious sedative agent in post-cardiac surgery patients: a meta-analysis? Critical Care 2012, 16:R169.
Competing interests
The author declares no conflicts of interest.