Thoracic epidural analgesia with levobupivacaine for 6 postoperative days attenuates sympathetic activation after thoracic surgery.
OBJECTIVE
To investigate the impact of 2 postoperative analgesic regimens on heart rate variability in patients who underwent thoracotomy.


METHODS
A prospective, randomized trial.


METHODS
A single-institutional study in a university hospital.


METHODS
Fifty patients who underwent thoracotomy under combined general anesthesia and thoracic epidural analgesia divided by a number generator into 2 equal groups (A and B).


METHODS
In group A, postoperative analgesia consisted of thoracic epidural analgesia with levobupivacaine for 6 postoperative days. In group B, on the 3rd postoperative day this regimen was changed to patient-controlled intravenous morphine. Heart rate variability recordings were performed on the day before surgery, after the epidural, after operation, and on every postoperative day. Statistical analysis used chi-square and Student t tests (Bonferroni correction).


RESULTS
In both groups, the low-frequency component of the analyzed recordings declined after epidural and after surgery. In group A, the low-frequency component was significantly lower compared with baseline from the 2nd postoperative day onward, whereas in group B it was significantly higher compared with A on the 4th and 6th postoperative days. In both groups, the changes in high frequency were statistically insignificant. Intergroup comparisons of the low-/high-frequency ratio showed statistical difference on the last day of observation. There was no difference between the groups in hemodynamic variables and visual analog scale/10 scores.


CONCLUSIONS
Postoperatively decreased cardiac sympathetic outflow continues with epidural analgesia, whereas it is abolished by the change to intravenous patient-controlled morphine.
Anesthesiology Clinic, University of Thessaly, Larissa, Greece.
Marina
M
Simeoforidou
George
G
Vretzakis
Metaxia
M
Bareka
Eleni
E
Chantzi
Andreas
A
Flossos
Athanasios
A
Giannoukas
Nikolaos
N
Tsilimingas
D000368:Aged; D015360:Analgesia, Epidural; D016058:Analgesia, Patient-Controlled; D000701:Analgesics, Opioid / Q000627:therapeutic use; D000768:Anesthesia, General; D000779:Anesthetics, Local / Q000627:therapeutic use*; D001341:Autonomic Nervous System / Q000502:physiology; D001794:Blood Pressure / Q000187:drug effects; D002045:Bupivacaine / Q000031:analogs & derivatives / Q000627:therapeutic use; D015716:Electrocardiography, Ambulatory; D005260:Female; D006321:Heart / Q000294:innervation; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D000077554:Levobupivacaine; D008297:Male; D008875:Middle Aged; D009020:Morphine / Q000627:therapeutic use; D011013:Pneumonectomy; D011182:Postoperative Care; D011446:Prospective Studies; D013564:Sympathetic Nervous System / Q000187:drug effects*; D019616:Thoracic Surgical Procedures / Q000009:adverse effects*; D013904:Thoracic Vertebrae; D013906:Thoracoscopy / Q000009:adverse effects
D000701:Analgesics, Opioid; D000779:Anesthetics, Local; D009020:Morphine; D000077554:Levobupivacaine; D002045:Bupivacaine