Continuous Thoracic Epidural Infusion Research Articles

Effects of adding midazolam on the postoperative epidural analgesia with two different doses of bupivacaine

Study Objective: To investigate the interaction of midazolam with different doses of bupivacaine, by comparing the analgesic, sedative, and amnesic effects of continuous epidural midazolam with two different doses of bupivacaine. Design: Prospective, randomized study. Setting: Operating room and intensive care units of a university hospital. Patients: 100 ASA physical status I and II postgastrectomy patients (40–70 yrs) without any complications. Interventions: Patients were divided into four groups (n = 25) and administered continuous thoracic epidural infusion (40 mL/12 hr) of the drugs via a balloon infuser. The contents of the infuser (40 mL) were bupivacaine 180 mg with midazolam 20 mg (HM group), 90 mg with midazolam 20 mg (LM group), 180 mg without midazolam (HC group), or 90 mg without midazolam (LC group). As a rescue medication, 50 mg indomethacin suppository was the first choice, then IM pentazocine 15 mg. Measurements: Analgesia and sedation scores, blood pressure (BP), heart rate, respiratory rate, oxygen saturation, amnesia, the number of rescue medications, and time to the first rescue medication were monitored. The area under the curves (AUCs) of analgesia and sedation scores, and BP were calculated. Main Results: In the HM group, significantly better analgesia and sedation were obtained and the number of rescue medications given was the lowest of the four groups. The time to the first rescue medication was longest in the HM group, followed by the LM group, then the HC, and, finally, LC groups. The numbers of the patients with amnesia were greater in the HM and LM groups than the HC and LC groups. Blood pressure decreased significantly in the HM group but no treatment was necessary. The AUCs of analgesia and sedation scores, and BP were lowest in the HM group. Conclusions: Adding midazolam increased not only analgesic but also sedative effect with increasing dose of bupivacaine in a postoperative continuous epidural administration.

Pain Management after Minimally Invasive Pectus Excavatum Repair

Purpose: To assess our experience with postoperative pain and analgesia requirements associated with the minimally invasive repair of pectus excavatum in children. Patients and Methods: a retrospective review of the charts of patients operated on between July 1998 and December 1999 was conducted, and all patients and parents were contacted by phone for interviews. Results: Thirty-one patients (8 girls and 23 boys) aged 3 to 18 years (median 9 years) were identified. The average length of stay was 4.7 days. In 29 children, continuous thoracic epidural infusions were initiated, and they were the mainstay of analgesia in 22 children (mean duration of infusion 65 hours). The remaining nine children required a combination of therapies for pain relief. Two patients required oral analgesia for >3 weeks after discharge, one of whom subsequently required surgical revision. Pain assessment using the Wong-Baker nonverbal scoring system showed that on any given day after surgery, children in the 3- to 10-year age group consistently scored lower than those in the 11- to 18-year age group. Conclusions: The length of stay and duration of continuous epidural infusions required after the minimally invasive repair of pectus excavatum in children is similar to that reported for the traditional open repair. Younger children (3-10 years) appeared to tolerate the procedure better than older children (11-18 years).

CONTINUOUS THORACIC EPIDURAL ANALGESIA FOLLOWING THORACOTOMY

S290 Introduction: Logas [1] reported that the quality of post-thoracotomy pain control was similar in patients treated with epidural morphine 0.1% alone or in combination with bupivacaine 0.1%. Others [2,3] have shown that the combination therapy of bupivacaine and other opioids are more effective than epidural opioids alone. We investigated the quality of pain relief and outcomes in post-thoracotomy patients treated with continuous thoracic epidural infusion of morphine 0.1% alone or in combination with bupivacaine 0.125%. After obtaining IRB approval and informed consent 23 ASA Class I, II or III patients undergoing open thoractomies were enrolled for this randomized, double blind, prospective study. Epidural catheters were placed preoperatively at the T6-T7 interspace and epidural placement was confirmed by obtaining appropriate sensory levels after injection of 2% lidocaine. All patients were given general anesthesia and IV fentanyl was limited to a maximum of 5 [micro sign]g/kg. Intraoperatively the epidural catheters were bolused with morphine and bupivacaine on a time contingent basis. Upon arrival in the PACU, the patients were randomly assigned to receive either morphine 0.1 mg/cc with or without bupivacaine 0.125% as a continuous infusion. If the initial VAS was > 3, the patient was bolused with epidural morphine, fentanyl, and study solution to achieve VAS < 3. Once a VAS below 3 was achieved, the patient was started on the appropriate epidural infusion at 5 mL/hr. Infusion rates were titrated (maximum of 7 mL/hr) in an attempt to keep VAS level < 3. Patients were monitored for 72 hrs postoperatively with measurement of VAS, side effect scores and epidural infusion rates Results Demographic data were similar among both groups. Of the 23 patients, 5 had to be discontinued from the study. In the morphine group, 3 patients were discontinued, 1 for persistent VAS > 3, 1 for catheter occlusion and a third at her own request. In the combination group, 2 patients were discontinued, 1 for persistent VAS > 3 and the second for refractory hypotension. Examination of the data showed no significant differences between both groups with respect to VAS (at rest and with cough), number of epidural boluses, supplementary non-opioid analgesia (Toradol), total number of postop days and epidural morphine requirement. There were no significant differences with respect to incidence of nausea/vomiting, sedation, mental confusion, respiratory depression and hypotension. Discussion: Based on the lack of significant differences between groups, in the measured variables, epidural bupivacaine 0.125%, at rate of 5-7 mL/hr, appears to provide no additional benefit over the use of morphine alone. Epidural morphine alone provides adequate analgesia for the management of postoperative thoracotomy pain. (Table 1)Table 1

Epinephrine Decreases Postoperative Requirements for Continuous Thoracic Epidural Fentanyl Infusions

Epidural thoracic fentanyl infusions provide effective preoperative analgesia after thoracotomy; however, side effects can limit the effectiveness of this technique. This study evaluates epinephrine as an adjunct to continuous thoracic epidural fentanyl infusions after thoracotomy. Thirty-eight patients were studied in a prospective, randomized, double-blind trial comparing fentanyl alone to fentanyl with epinephrine 1:300,000. Epidural infusion rates were titrated to equivalent pain relief using a visual analog scale. With the addition of epinephrine, there was a significant reduction in fentanyl requirements (0.82 +/- 0.07 vs 1.19 +/- 0.11 micrograms.kg-1.h-1, P = 0.005, repeated-measures analysis of variance) and in plasma fentanyl concentrations (steady state: 0.91 +/- 0.13 vs 1.65 +/- 0.23 ng/mL, P = 0.007, repeated-measures analysis of variance). There were no differences in pain scores, side effects, spirometry, patient satisfaction scores, or hemodynamic variables. This study demonstrates that adding epinephrine 1:300,000 to continuous thoracic epidural infusions decreases fentanyl requirements titrated for effective analgesia. The reduction in fentanyl requirements was associated with reduced fentanyl plasma concentrations.

Epinephrine Decreases Postoperative Requirements for Continuous Thoracic Epidural Fentanyl Infusions

Epinephrine Decreases Postoperative Requirements for Continuous Thoracic Epidural Fentanyl Infusions

Continuous thoracic epidural infusions for postoperative analgesia after pectus deformity repair

Purpose: To determine whether continuous epidural analgesia after repair of a pectus deformity is a viable and safe alternative to high-dose narcotics in children. Methods: Data were collected prospectively for 19 children (4 to 17 years of age; 15 boys, 4 girls) who underwent pectus excavatum (14) or carinatum (5) repair between June 1, 1991 and July 1, 1994. Seventeen had a thoracic epidural catheter placed for postoperative pain control and two did not. The epidural catheter was routinely placed preoperatively by the anesthesiologist at the T3–T8 level, after induction of general anesthesia. Epidural catheters were test-dosed with local anesthesia alone or in combination with fentanyl, and after-ward a continuous epidural infusion was maintained on the floor. Postoperative pain was assessed by nursing and house staff on the Wong-Baker scale, with adjustment of the dose rate or analgesic medication as appropriate. Results: All patients had extubation before leaving the operating room and were sent to the general pediatrics ward after leaving the recovery room. The average duration of the epidural was 69 hours (range, 20 to 116 hours). Sixteen patients received their test epidural dose preoperatively, and one patient had his in the recovery room. Fifteen epidurals initially were dosed with bupivicain (1 to 2 mg/kg) alone or in combination with fentanyl (1 to 2 μg/kg). Two patients received initial doses of lidocaine (1 to 1.5 mg/kg). Ten of 17 patients received fentanyl (1 μg/kg/h) with bupivicaine (0.5 to 1.0 mg/kg/h) in the epidural as their maintenance medication, and the remainder received bupivicaine alone at the same dosage rate. Eight of 17 patients required additional intermittent supplemental narcotics, with an average of two doses of intravenous morphine per day (0.1 mg/kg) over the first 3 postoperative days. In contrast, the two patients who did not have an epidural catheter for pain control required high-dose intravenous morphine (0.2 mg/kg) every 2 to 3 hours for the first 3 to 4 postoperative days. No catheter-related complications occurred. Conclusion: Thoracic epidural analgesia was completely successful in nine (53%) children who underwent repair of pectus deformity, and effectively reduced the intravenous narcotic demand in the other eight. Pain control was excellent, and no catheter-related complications were encountered. The data show that this method of analgesia in children is a safe and attractive alternative to intravenous narcotics, and eliminates the potential disadvantages of sedation and respiratory compromise.

Thoracic epidural analgesia with bupivacaine and fentanyl for postoperative thoracotomy pain

This study was designed to evaluate the potential fentanyl-sparing effect of a dilute local anesthetic, bupivacaine, administered in fixed combinations with fentanyl for post-thoracotomy analgesia via a continuous thoracic epidural infusion. Forty adult patients scheduled for thoracotomy were randomly allocated in a double-blind fashion to receive an epidural infusion containing 0, 0.03, 0.06, or 0.125% bupivacaine in combination with fentanyl (4 μg/mL). The epidural infusions were initiated in the operating room at 10 mL/hr. During the first 24 hours, there were no between-group differences in pain scores. Total fentanyl use was significantly decreased 24% to 33% in all bupivacaine treatment groups. However, fentanyl plasma levels at 24 hours were not significantly different between groups. Arterial blood gas measurements performed on the morning after surgery revealed significant reductions in PaCO 2 values, 38 ± 4, 36 ± 4, 37 ± 4 mmHg for 0.03, 0.06, and 0.125% bupivacaine groups respectively, versus 44 ± 6 for the plain fentanyl group. Arterial pH values were significantly higher in all bupivacaine treatment groups. These findings suggest that the combination of dilute bupivacaine with fentanyl for thoracic epidural analgesia for post-thoracotomy pain may have beneficial effects on pulmonary gas exchange.

Continuous thoracic epidural analgesia for the control of pain in myocardial infarction.

Continuous thoracic epidural infusion of bupivacaine 0.25% for the relief of pain in acute myocardial infarction (AMI) was studied. The method was only employed for patients, who could not obtain adequate pain relief by parenteral opioid analgesics without unacceptable respiratory depression and/or emesis. The method was effective in controlling pain. The systolic blood pressure was reduced significantly, while the diastolic blood pressure and the heart rate did not change.