Journal of Anesthesia (2018) 32:461
LETTER TO THE EDITOR
Blind method regarding the eﬀect of dexmedetomidine on CRBD
· Haiyan Zhou
· Xiaohua Zou
Received: 19 February 2018 / Accepted: 12 April 2018 / Published online: 26 April 2018
© Japanese Society of Anesthesiologists 2018
To the Editor:
We have read an article written by Kwon et al. with great
interest . It is a welcome investigation which evaluated
the eﬀect of the intraoperative dexmedetomidine (DEX) on
the incidence and severity of catheter-related bladder dis-
comfort (CRBD) after nonurologic surgery. We agree with
their conclusion that DEX may have beneﬁts in preventing
CRBD after lumbar microdiscectomy. However, we have a
question regarding the blind method.
In this article, the author stated that DEX was infused
at a loading dose of 1 µg/kg over 10 min, followed by a
continuous infusion of 0.3–0.5 µg/ kg/h, the dose of which
is adjusted by the operator based on blood pressure, heart
rate, and BIS values in group D (experimental group), while
an identical volume of 0.9% saline was infused in the same
manner in the group C (control group). According to the
author’s description, the operator was aware of both groups
for each individual. In other words, the operator was not
blinded, which may cause the possibility of observation bias.
We suggest that the study drugs (DEX 200 µg/2 mL and
normal saline 2 mL) should be diluted into the same syringe
with normal saline to 50 mL, and infused at a loading rate of
0.25 mL/kg over 10 min, followed by a continuous infusion
of 0.075–0.125 mL/kg/h according to the study of Su et al
, but not at the dose of DEX (µg/kg/h), so that the opera-
tor is blinded to the group allocation.
Compliance with Ethical Standards
Conflict of interest None declared.
1. Kwon Y, Jang JS, Hwang SM, Lee JJ, Tark H. Intraoperative
administration of dexmedetomidine reduced the postoperative
catheter-related bladder discomfort and pain in patients undergo-
ing lumbar microdiscectomy[J]. Journal Anesth. 2017:1–7.
2. Su X, Meng ZT, Wu XH, Cui F, Li HL, Wang DX, Zhu X,
Zhu SN, Maze M, Ma D. Dexmedetomidine for prevention of
delirium in elderly patients after non-cardiac surgery: a ran-
domised, double-blind, placebo-controlled trial[J]. Lancet.
Bailong Hu, Haiyan Zhou and Xiaohua Zou contributed equally to
This comment refers to the article available at: https ://doi.
* Bailong Hu
Department of Anesthesiology, The Aﬃliated Hospital
of Guizhou Medical University, No. 28 Guiyi Street, Yunyan
District, 550004 Guiyang, China
Department of Clinical Research Centre, The Aﬃliated
Hospital of Guizhou Medical University, No. 28 Guiyi Street,
Yunyan District, 550004 Guiyang, China