Baylor University Medical Center Proceedings January 2014, Volume 27, Number 1 | Page 9

Table 2. Results for subjects randomized to placebo compared to intravenous
dexmedetomidine
Placebo group
(n = 19)

Variable

Dexmedetomidine
group (n = 19)

P
value

a. Demographic characteristics
Age (years)

56 ± 13

Male

61 ± 11

0.24

7 (37%)

8 (42%)

Female

12 (63%)

11 (58%)

Weight (kg)

79.4 ± 20.4

79.2 ± 14.8

Body mass index

25.8 ± 5.4

25.3 ± 4.8

African American

0

1 (5%)

Asian

0

1 (5%)

19 (100%)

17 (89%)

Total infusion time (minutes)

1281 ± 288

1214 ± 347

0.52

Total study drug administered (mcg)

496†

± 239

497 ± 268

0.50

541 ± 257

576 ± 282

0.35

Caucasian

1.0
0.97
0.35

b. Drug administration

Total study drug administered
(mcg) adjusted to 24 hours

0.60

Early withdrawal
Consent withdrawn
Hypotension
Pneumonia
Volume depletion

—
—
—
1 (5%)

1 (5%)
1 (5%)
1 (5%)
—

IV morphine equivalency
administered (mg)

49 ± 35

29 ± 26

0.03*

IV morphine equivalency
administered (mg) adjusted
for total time on study drug

54 ± 37

35 ± 28

0.04*

c. Type of opioid use
PCA

Morphine sulfate: 18
Hydromorphone: 1

Morphine sulfate: 17
Hydromorphone: 2

Supplemental opioids

Hydrocodone: 3
Meperidine (IV): 1
Hydrocodone/fentanyl (IV): 1

Hydrocodone: 4
Hydromorphone: 1
Fentanyl (transdermal): 1

d. Vital signs
Systolic blood pressure (mm Hg)

125 ± 11.4

114 ± 11.1

Diastolic blood pressure
(mm Hg)

65 ± 7.4

64 ± 5.3

0.008*
0.41

Heart rate (beats per minute)

90 ± 12.3

80 ± 12.3

0.01*

Respiratory rate (breaths per
minute)

20 ± 2.8

19 ± 2.3

0.41

drug was resumed only with a systolic
blood pressure of >89 mm Hg and after
a minimum of 30 minutes and no longer
than 4 hours had passed. Three of the five
subjects, one in the placebo group and
two in the dexmedetomidine group, did
not require any interventions, and the
study drug was resumed with no further
complications. One dexmedetomidine
subject experienced mild hypotension
and had the study drug interrupted and
restarted 30 minutes later with no interventions. Five and a half hours later, this
same subject experienced hypotension
and the study drug was interrupted. The
study drug remained off and the subject
was withdrawn from the study due to
pneumonia and the sepsis syndrome that
had developed. This same subject also
was the one dexmedetomidine subject to
experience tachycardia. A second dexmedetomidine subject had the study drug
interrupted due to hypotension, which
required treatment of a 250 mL normal
saline bolus. The study drug was resumed
95 minutes later. This subject was withdrawn from the study 70 minutes after
the second start of the study drug when
it was discovered that a concurrent betablocker had been administered and the
subject experienced a second episode of
hypotension.
Adverse events associated with opioid
administration such as constipation, nausea, and pruritus were reported in greater
numbers in the placebo group (placebo =
12 vs dexmedetomidine = 4). The odds
ratio of developing one of these side effects in the dexmedetomidine group was
0.3 compared with the placebo group,
with a 95% confidence interval of (0.07,
1.23).

Pulse oximetry (%)

98 ± 1.6

97 ± 1.7

0.13

Transcutaneous carbon dioxide
(mm Hg)

44 ± 5.3

43 ± 6.7

0.58

Pain score

3 ± 1.7

3 ± 2.3

0.52

Ramsay Sedation Scale

2 ± 0.1

2 ± 0.1

0.01*

*P < 0.05.
†Calculated based on infusion rates assuming concentration of dexmedetomidine group.
Data are presented as mean ± standard deviation or n (%).

January 2014

DISCUSSION
The standard procedure for managing postoperative pain for thoracotomy
patients in this institution is to provide a
paraverteb Ʌ