Baylor University Medical Center Proceedings January 2014, Volume 27, Number 1 | Page 5

Dexmedetomidine infusion for analgesia up to 48 hours after
lung surgery performed by lateral thoracotomy
Michael A. E. Ramsay, MD, Kate B. Newman, BSN, CCRC, Barbara Leeper, MN, CCRN, Baron L. Hamman, MD, Robert F. Hebeler
Jr., MD, A. Carl Henry, MD, Harry Kourlis Jr., MD, Richard E. Wood, MD, Jack A. Stecher, MD, and H. A. Tillmann Hein, MD

Patients undergoing a lateral thoracotomy for pulmonary resection have
moderate to severe pain postoperatively that is often treated with opioids.
Opioid side effects such as respiratory depression can be devastating in
patients with already compromised respiratory function. This prospective
double-blinded clinical trial examined the analgesic effects and safety of
a dexmedetomidine infusion for postthoracotomy patients when administered on a telemetry nursing floor, 24 to 48 hours after surgery, to determine if the drug’s known early opioid-sparing properties were maintained.
Thirty-eight thoracotomy patients were administered dexmedetomidine
intraoperatively and overnight postoperatively and then randomized to
receive placebo or dexmedetomidine titrated from 0.1 to 0.5 μg∙kg∙h−1
the day following surgery for up to 24 hours on a telemetry floor. Opioids
via a patient-controlled analgesia pump were available for both groups,
and vital signs including transcutaneous carbon dioxide, pulse oximetry,
respiratory rate, and pain and sedation scores were monitored. The dexmedetomidine group used 41% less opioids but achieved pain scores
equal to those of the placebo group. The mean heart rate and systolic
blood pressure were lower in the dexmedetomidine group but sedation
scores were better. The mean respiratory rate and oxygen saturation
were similar in the two groups. Mild hypercarbia occurred in both groups,
but periods of significant respiratory depression were noted only in the
placebo group. Significant hypotension was noted in one patient in the
dexmedetomidine group in conjunction with concomitant administration
of a beta-blocker agent. The placebo group reported a higher number of
opioid-related adverse events. In conclusion, the known opioid-sparing
properties of dexmedetomidine in the immediate postoperative period
are maintained over 48 hours.

he provision of excellent and safe postoperative pain
management for patients who have undergone a major
thoracotomy for lung or partial lung resection is challenging. Inadequate pain control may result in splinting
of the chest, poor chest excursion, atelectasis, and respiratory
failure. Pain management based on an opioid-based protocol
runs the risk of adverse drug events related to narcotics. Several
recent reports have demonstrated that respiratory depression
and deep levels of sedation can occur when morphine patientcontrolled analgesia (PCA) is prescribed (1–7). The patient with
compromised pulmonary function may be at an increased risk
for an adverse event.

T

Proc (Bayl Univ Med Cent) 2014;27(1):3–10

Dexmedetomidine, an alpha 2-adrenoceptor agonist,
has been used to provide sedation in critical care patients
and has been demonstrated to reduce opioid requirements,
cause minimal respiratory depression, and improve outcomes
(8–22). We hypothesized that the addition of a dexmedetomidine infusion to the postoperative pain management protocol
would reduce the amount of morphine delivered by a PCA
pump, reduce the opioid-induced adverse drug effects, and
provide adequate analgesia for postthoracotomy patients. We
also hypothesized that once the patient had been receiving
dexmedetomidine for 24 hours, the infusion could be administered safely on a monitored telemetry unit as opposed to an
intensive care unit (ICU) to maintain a good level of responsiveness and comfort, a Ramsay Sedation Score (RSS) of 2 to
4 (23), and hemodynamic stability. A prospective, doubleblinded, controlled clinical pilot trial was designed to test these
hypotheses.
METHODS
Institutional review board approval was obtained at Baylor
University Medical Center at Dallas to enroll patients undergoing major open thoracotomy surgery between November
2006 and October 2007. All subjects were between 18 and
85 years of age and had an American Society of Anesthesiologists physical status of 3 or under. Subjects were excluded from
enrollment if they had serious central nervous system pathology, a left ventricular ejection fraction of <30%, conduction
abnormalities with the exception of first-degree atrioventricular
block and rate-controlled atrial fibrillation, acute or chronic
hepatitis, a requirement for renal supplementation, a known
uncontrolled seizure disorder, a known or suspected physical
or psychological dependence on an abused drug other than
alcohol, or a psychiatric illness that would confound a normal response to sedative treatment or if they were pregnant or

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