The effect of fentanyl administered epidurally by patient-controlled analgesia, continuous infusion, or a combined technique of oxyhaemoglobin saturation after abdominal surgery

Comparative Study of 0.5% Bupivacaine, 0.5% Ropivacaine, and 0.75% Ropivacaine With Fentanyl as a Continuous Intraoperative Epidural Infusion on Post-operative Analgesia

Introduction Persistent postoperative pain leads to impaired patient recovery and delays in discharge of patients. The aim was to compare the efficacy of 0.5% bupivacaine to two varying concentrations of ropivacaine, specifically 0.5% and 0.75%, along with fentanyl as a continuous epidural infusion in providing adequate pain relief for patients subjected to infraumbilical surgeries. Materials and methods A prospective randomized comparative study was carried out on 150 patients and was divided into three groups, namely group B, group R, and group RP. Group B indicates (0.5% bupivacaine), group R means (0.5% ropivacaine), and finally, group RP means (0.75% ropivacaine); the three groups had 50 patients each. Group B was administered an epidural infusion of bupivacaine at a concentration of 0.5%, group R was given 0.5% ropivacaine, and group RP was treated with 0.75% ropivacaine; all three groups included 40 mcg fentanyl. The duration of the motor and sensory blockade and the time needed for the first rescue analgesia after the stoppage of epidural infusion were assessed in all three groups. The data were statistically analyzed using the ANOVA, "post hoc Tukey," and chi-square tests. Results Comparison of the duration of motor and sensory blockade among all three groups showed that group RP (0.75% ropivacaine with 2 mcg/cc fentanyl) had the longest duration of 328.8 and 406 minutes, and the difference was statistically significant (p < 0.001). Comparison of the time of stoppage of epidural infusion to the requirement of first rescue analgesia showed that the group that received 0.75% ropivacaine with 40 mcg fentanyl had the highest value of 258.6 minutes and was statistically significant (p < 0.001). Conclusion Epidural intraoperative infusion of 0.75% ropivacaine with fentanyl offers better postoperative pain relief as compared to both 0.5% bupivacaine and 0.5% ropivacaine with fentanyl.

Patient-controlled analgesia in the management of postoperative pain

Patient-controlled analgesia (PCA) is a delivery system with which patients self-administer predetermined doses of analgesic medication to relieve their pain. Since its introduction in the early 1980s, the daily management of postoperative pain has been extensively optimised. The use of PCA in hospitals has been increasing because of its proven advantages over conventional intramuscular injections. These include improved pain relief, greater patient satisfaction, less sedation and fewer postoperative complications. All PCA modes contain the following variables: initial loading dose, demand dose, lockout interval, background infusion rate and 1-hour or 4-hour limits. Morphine is the most studied and most commonly used intravenous drug for PCA. In spite of the fact that it is the 'first choice' for PCA, other opioids have been successfully used for this option. The most observed adverse effects of opioid-based PCA are nausea and vomiting, pruritus, respiratory depression, sedation, confusion and urinary retention. Although intravenous PCA is the most studied route of PCA, alternative routes have extensively been described in the literature. PCA by means of peridural catheters and peripheral nerve catheters are the most studied. Recently, transdermal PCA has been described. The use of peripheral or neuraxial nerve blocks is recommended to avoid the so called opioid tolerance observed with the intravenous administration of opioids. Numerous studies have shown the superiority of epidural PCA to intravenous PCA. The beneficial postoperative effects of epidural analgesia are more apparent for high-risk patients or those undergoing higher risk procedures. PCA with peripheral nerve catheters results in increased postoperative analgesia and satisfaction for surgery on upper and lower extremities. Serious complications occur rarely with these catheters. With the introduction of an Acute Pain Service, management of postoperative pain can be improved. This will also help to minimise adverse effects related to PCA and to avoid lethal mishaps.

Apnea and bradypnea in patients receiving epidural bupivacaine-morphine for postoperative pain relief as assessed by a new monitoring method

STUDY OBJECTIVE

To evaluate postoperative breathing patterns with a new monitoring device in patients given bupivacaine-morphine epidural analgesia.

DESIGN

Open explorative study.

SETTING

Inpatient anesthesia in a university hospital setting.

PATIENTS

15 ASA physical status I and II patients aged 28 to 87 years and scheduled for major abdominal surgery.

INTERVENTIONS

All patients underwent abdominal surgery with epidural anesthesia combined with general anesthesia. Postoperatively, they continued with epidural analgesia consisting of bupivacaine and morphine. On the first postoperative night, the breathing pattern was studied with a new noninvasive monitoring device measuring respiratory frequency and apnea. Arterial blood gas analysis was performed in case of apnea or low respiratory frequency.

MEASUREMENTS AND MAIN RESULTS

A total of 84 alarm events were registered in 11 patients. Twenty-one percent (18/84) of the alarms were associated with arterial carbon dioxide tension (PaCO2) levels greater than 48.8 mmHg. Three of the four patients with PaCO2 levels greater than 48.8 mmHg were older than 80 years of age.

CONCLUSION

The tested noninvasive monitoring device may detect abnormal respiratory breathing patterns in patients at risk for respiratory depression during epidural analgesia with bupivacaine-morphine.

New developments in epidural anesthesia and analgesia

Several recent advances in epidural anesthesia and analgesia have been reviewed. Perhaps the most exciting area of anticipated future developments relates to the continued development of novel analgesic agents and new epidural delivery systems. There appears to be some movement toward an increased use of intrathecal or peripheral neural blockade techniques for some clinical situations where epidural anesthesia and analgesia have been previously used; however, the ability to provide anesthesia and analgesia to relatively large areas of the body with a single injection or continuous catheter technique without the associated risks of dural puncture and intrathecal catheter placement will continue to assure epidural anesthesia and analgesia techniques a prominent role in anesthesia and pain management.

Epidural and spinal agents for postoperative analgesia

The discovery of opioid receptors and the subsequent development of the technique of epidural and intrathecal opioid administration are undoubtedly two of the most significant advances in pain management in recent decades. The use of spinal opioids is widespread and increasing. The technique is used widely to treat intraoperative, postoperative, traumatic, obstetric, chronic, and cancer pain. Newer developments include the increasing use of combined local anesthetics and opioids or nonopioids and also PCEA, particularly in the obstetric population. Meta-analysis of controlled trials has demonstrated improved pulmonary outcome in patients receiving epidural postoperative analgesia. Although rare, respiratory depression continues to be a major problem of the technique. None of the currently available opioids is completely safe; however, extensive international experience has shown that patients receiving spinal opioids for postoperative analgesia can be safely nursed on regular wards, provided that trained personnel and appropriate guidelines are available. The importance of a good acute pain service to provide the safe and effective use of spinal opioids cannot be overemphasized.

Ventilatory pattern and associated episodic hypoxaemia in the late postoperative period in the general surgical ward

Episodic oxygen desaturation is frequent in the late postoperative period and seems most pronounced on the second and third postoperative nights. However, the ventilatory pattern has not been described systematically during this period. We studied the ventilatory pattern and associated arterial oxygenation using the Edentrace II equipment (impedance pneumography and pulse oximetry) on the second and third postoperative nights in 28 patients undergoing major abdominal surgery. Ventilatory disturbances were common and included periods of hypopnoea, and obstructive, central and mixed apnoeas. Overall, the median (range) respiratory disturbance index (apnoeas + hypopnoeas per h) was 12 (0-121), with the patients spending 6% (0-65%) of the night in some kind of ventilatory disturbance. It was not possible from pre-operative snoring habits to predict patients who developed postoperative ventilatory disturbances. Overall, 23% (0-100) of the hypopnoeas and 7% (0-100) of the apnoeas were associated with episodic hypoxaemia. In conclusion, ventilatory disturbances were common in the late postoperative period in the general surgical ward and often associated with episodes of oxygen desaturation.

Patient-controlled epidural versus intravenous pethidine to supplement epidural bupivacaine after abdominal aortic surgery

In a double-blind, randomized, crossover study of 25 patients after abdominal aortic surgery, we compared patient-controlled analgesia (PCA) with epidural versus intravenous pethidine. All patients received continuous epidural infusions of 0.125% bupivacaine adjusted to maintain appropriate sensory levels. The 48 hour study period commenced 36 to 48 hours after surgery and covered postoperative days 2 and 3. There was a crossover in PCA mode (epidural or intravenous) after 24 hours. Plasma pethidine concentration at the end of each 24 hour period and the total 24 hour pethidine dose did not change significantly between postoperative days 2 and 3. Pethidine plasma concentration was lower after 24 hours epidural than after intravenous PCA [125 (SD 108) ng/ml versus 171 (SD 107) ng/ml, P = 0.03], although pethidine dose did not differ significantly [mean 147 (SD 124) mg/24 h]. Visual analog pain scores (VAS) did not differ significantly between postoperative days 2 and 3, or at rest between epidural and i.v. groups. However, VAS with coughing and with abdominal palpation were lower in the epidural PCA group (P = 0.05, 0.008). With a background epidural infusion of 0.125% bupivacaine, PCA with epidural pethidine provided better pain control than PCA intravenous pethidine and this was achieved at lower plasma pethidine concentrations.

Postoperative patient-controlled epidural analgesia with opioid bupivacaine mixtures

PURPOSE

To determine the efficacy and safety of patient-controlled epidural analgesia of morphine or fentanyl in combination with bupivacaine for postoperative pain relief.

METHODS

Forty ASA I-II patients scheduled for major abdominal surgery were studied. After insertion of a lumbar epidural catheter, patients were given a non-opioid general anaesthetic. After surgery patients complaining of pain, received a loading dose of 2 mg morphine (Group I) or 50 micrograms fentanyl (Group II). For continuing pain, 1 mg morphine in 4 ml bupivacaine 0.125% (0.25 mg.ml-1 morphine and 1 mg.ml-1 bupivacaine, Group I) or 20 micrograms fentanyl in 4 ml bupivacaine 0.125% (5 micrograms.ml-1 fentanyl and 1 mg.ml-1 bupivacaine Group II) were administered. Blood pressure, heart rate, respiratory rate and SpO2 were monitored. Assessments of pain (VAS), nausea-vomiting, motor block, pruritus and sedation were recorded for 24 hr.

RESULTS

No difference in pain or sedation was observed between groups. The 24 hr postoperative opioid consumption was 15.50 +/- 7.53 mg morphine and 555.10 +/- 183.85 micrograms fentanyl. Total bupivacaine 0.125% consumption was 58.00 +/- 30.14 ml in Group I and 101.05 +/- 36.77 ml in Group II. One patient in Group II complained of motor weakness in one leg. The incidence of nausea (Group I 45%, Group II 10% P < 0.05) and pruritus (Group I 30%, Group II 5% P < 0.05) was less in patients receiving fentanyl.

CONCLUSION

Both methods were effective in the prevention of pain but, because of fewer side effects, fentanyl may be preferable to morphine.

Patient-controlled epidural analgesia after caesarean section using meperidine

PURPOSE

To determine the effects of the addition of a background infusion to patient-controlled epidural analgesia (PCEA) using meperidine for analgesia after Caesarean section.

METHODS

In a randomized, double-blind study, we assigned 40 patients having elective Caesarean section to receive postoperative analgesia by patient-controlled epidural analgesia (PCEA) using meperidine 5 mg.ml-1 with (group Pi) or without (group Po) a background infusion of 10 mg.hr-l. The PCEA settings (20 mg bolus, 10 min lockout interval, four-hour maximum dose 150 mg) were otherwise identical. We compared pain at rest, pain on coughing, side effects, number of PCEA demands, drug consumption and patient satisfaction between groups in the first 24 hr after surgery.

RESULTS

Total consumption of meperidine was greater in group Pi (median 390 mg) than in group Po (median 240 mg; P = 0.017) and the number of PCEA demands was greater in group Po (median 12) than in group Pi (median 7.5; P = 0.012). Analgesia, side effects and patient satisfaction was similar between groups.

CONCLUSION

Addition of a background infusion to PCEA using meperidine after Caesarean section has no clinical benefit.

Epidural sufentanil for postoperative patient-controlled analgesia (PCA) with or without background infusion: a double-blind comparison

To evaluate the usefulness of a concurrent infusion in patient-controlled epidural analgesia (PCEA), 40 patients scheduled for elective cesarean section under a combined spinal-epidural technique were assigned randomly in a double-blind fashion to receive sufentanil by PCEA with a concomitant infusion of either sufentanil or saline. The sufentanil 24-h consumption was significantly (P < 0.001) higher in those patients receiving the opioid-containing infusion (212.7 +/- 9.5 vs 128.4 +/- 10.8 micrograms, SEM). The number of additional demands and the quality of sleep did not differ between the two groups. The degree of sedation was significantly less pronounced in patients treated with incremental sufentanil doses only. The visual analog scale (VAS) pain scores at rest were identical in both groups except at 6 h (2.5 +/- 0.4 vs 3.7 +/- 0.3, in favor of the patients treated with the sufentanil background infusion). We conclude that, except for a lower pain score during the initial hours, a background infusion in PCEA with sufentanil does not offer major advantages in terms of sleep quality or sufentanil consumption. Side effects may be more pronounced owing to increased drug administration.

Continuous administration of fentanyl for postoperative pain: a comparison of the epidural, intravenous, and transdermal routes

STUDY OBJECTIVES

To evaluate the influence of the route of administration [epidural, intravenous (IV), or transdermal] on onset and quality of analgesia and to evaluate the pharmacokinetics of continuous administration of fentanyl.

DESIGN

Randomized, open, single-dose, prospective study.

SETTING

Postanesthesia care unit of a university hospital.

PATIENTS

54 ASA physical status I-III patients scheduled for lower major abdominal, gynecologic, or urologic surgery.

INTERVENTIONS

Patients were assigned to 1 of 3 comparable groups, to receive, for 72 hours postoperatively, an IV (Group IV) or epidural (Group EP) constant-rate infusion of fentanyl (loading dose 1.5 micrograms/kg, infusion rate 1 micrograms/kg/hr), or a transdermal patch (Group TTS), applied preoperatively, delivering fentanyl 75 micrograms/hr.

MEASUREMENTS AND MAIN RESULTS

Pain intensity, vital signs, blood gas status, and plasma fentanyl concentration (Cp) were measured for up to 96 hours postoperatively. Onset of analgesia was delayed in Group TTS. Analgesic efficacy was similar for all 3 routes of administration except during the first 4 hours in Group TTS. Initially, the patients in Groups TTS and IV needed significantly more rescue morphine than those in Group EP. The time course for fentanyl Cp in Groups TTS and IV evolved to similar plateau levels. However, fentanyl Cp continued to rise throughout the study period in Group EP, reaching concentrations that elicited hypoxemia after 48 hours. A significant negative relationship existed between fentanyl Cp and oxygen saturation in this group. All 3 routes of administration showed similar frequencies of side effects (i.e., nausea, vomiting, pruritus, and ileus).

CONCLUSIONS

The epidural, transdermal, and IV administration of identical doses of fentanyl given at a constant rate provided almost equivalent degrees of analgesia. But continuing epidural administration produced a steady rise in systemic fentanyl concentrations into the ventilatory-depressant range, affecting the hypoxemic regulation of breathing.