Baylor University Medical Center Proceedings January 2014, Volume 27, Number 1 | Page 6

lactating. Prior to enrollment, subjects were screened for study
eligibility. Informed consent was obtained prior to the initiation
of any study procedures.
The medical history was reviewed and subjects underwent
routine preoperative assessment and examination. The patients then underwent the standard anesthetic management
for thoracic surgery at this institution. General anesthesia
was induced with propofol, fentanyl, and sevoflurane and
relaxation provided with vecuronium. Anesthesia continued
utilizing one-lung ventilation with intraoperative fentanyl,
sevoflurane, and an intraoperative infusion of dexmedetomidine at 0.2 to 0.5 μg·kg·h-1 with no initial bolus. At the end
of surgery, an injection of 5 cc ropivacaine 0.5% plain paravertebral block at levels T4, 5, 6, and 7 was provided. Patients
emerged from the operating room extubated and awake with
continuous local anesthetic wound infiltration delivered by
an elastomeric infusion pump and stayed overnight in the
ICU or postanesthesia care unit (PACU). Patients continued

HR >50 but <110 bpm
and
SBP >90 but <180 mmHg

RSS=1
Increase study drug by
-1 to maximum rate of
0.1 µg·kg·hr
0.5 µg·kg·hr -1

REASSESS IN 30 MIN.

NO

RSS=5
or
RSS=6

YES

to receive dexmedetomidine intravenously titrated from 0.2
to 0.5 μg·kg·h−1 during their ICU or PACU stay to provide
adequate analgesia and comfort. Supplementary opioids were
administered by a PCA pump.
Approximately 18 to 24 hours after surgery, patients were
discharged from the ICU or PACU to the telemetry unit. Prior
to discharge they were randomized to receive either normal saline or dexmedetomidine continuously infusing at a rate titrated
between 0.1 and 0.5 μg·kg·h−1 for up to 24 hours. A morphine
PCA pump was available for both groups of patients. The intravenous dexmedetomidine infusion was stopped and the study
drug was started in the ICU or PACU 30 minutes prior to
transfer to the telemetry unit. Study infusion was titrated by
0.1 μg·kg·h−1 increments in 30-minute intervals to maintain
a pain score <5 on a 0 to 10 numeric pain scale, an RSS from
2 to 4, a systolic blood pressure >89 and <181 mm Hg, and a
heart rate >49 and <111 beats per minute. The decision tree
for titration is shown in Figure 1.

HR <50 bpm
or
SBP <90 mmHg

NO

NO

If unable to restart study drug
after 2 hours,
contact investigator

YES

YES

NO

NO

HR >110 or SBP >180
Call Investigator or attending
for clinical evaluation

Study drug to be
turned off

RSS=2,
RSS=3,
or
RSS=4
YES

Reassess in 30 minutes

Decrease study drug
by 0.1 µg·kg·hr -1

REASSESS IN 30 MIN.
NO

HR>50 bpm,
SBP>90 mmHg,
and RSS<5

This decrease
results in stopping
infusion of
study drug?

YES

Resume study drug at
0.1 µg·kg·hr -1

YES

REASSESS IN 30 MIN.

Reassess in 30 minutes

If unable to restart study drug
after 2 hours,
contact investigator

NO

HR>50 bpm,
SBP>90 mmHg,
and RSS<5

YES
REASSESS IN 30 MIN.

Resume study drug at
0.1 µg·kg·hr -1

Pain Score<5
NO

Increase study drug
by 0.1 µg·kg·hr -1
to maximum rate of 0.5 µg·kg·hr -1

REASSESS IN 30 MIN.

YES
REASSESS AT SCHEDULED 2-HOUR INTERVALS
No change in study drug rate

Figure 1. Titration decision tree.
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Baylor University Medical Center Proceedings

Volume 27, Number 1