Original ContributionComparison of ropivacaine with and without fentanyl vs bupivacaine with fentanyl for postoperative epidural analgesia in bilateral total knee replacement surgery☆,☆☆
Introduction
Osteoarthritis or the “degenerative joint disease” is an abnormality involving degradation of large joints. Joint replacement surgery is indicated when pain due to osteoarthritis is persistent and is associated with debilitation and/or significant joint movement limitation.
Pain after total knee replacement (TKR) interferes with early rehabilitation. Unrelieved postarthroplasty pain may result in “clinical” (deep vein thrombosis, pulmonary embolism, coronary ischemia, myocardial infarction, pneumonia, poor wound healing, and insomnia) [1], [2] and “psychological” changes that increase patient morbidity as well as the associated costs [1]. Negative clinical outcome resulting from ineffective post-TKR pain management and the add-on medical and economic implications (extended length of stay, readmission, and patient dissatisfaction) worsen the problem [3]. Therefore, not only adequacy of post-TKR analgesia is vital to early postoperative mobilization and successful rehabilitation but also is a key to successful functional outcome [4].
Bupivacaine, the most widely used local anesthetic (LA) for epidural analgesia, is a chiral compound [5] and racemic mixture of S (−) and R (+) enantiomers. Typically, selective epidural administration of S-enantiomers, for example, ropivacaine, produces rarer motor blockade than racemic mixture of bupivacaine [6]. Although ropivacaine and bupivacaine are quite similar in structure, the former is relatively less toxic in terms of cardiovascular and central nervous systems effects [7]. There is evidence that suggests that epidural ropivacaine results in greater sensory blockade and motor block sparing and has lower cardiac toxicity [7] potential than bupivacaine [8].
Interestingly, Polley et al [9] who calculated the relative potencies of LA agents (bupivacaine and ropivacaine) by using an up-down sequential allocation study design reported ropivacaine to be significantly less potent than bupivacaine (potency ratio, 0.6) [9]. However, they contended that, for practical clinical situations, different LA solutions provide the same analgesic effectiveness.
Addition of fentanyl to epidural LA agent is not uncommon. There is evidence that epidurally administered LA when combined with opioids decreases LA requirements and potentiates pain relief [10]. However, addition of fentanyl to epidural LA adds to complications, such as nausea-vomiting, itching, sedation, and delayed respiratory depression [11].
With the contention that epidural ropivacaine, when administered alone, produces sensory blockade equivalent to racemic bupivacaine and because it has selective action on the pain transmitting Aδ and C fibers, it can decrease the need of adding fentanyl to epidural LA solution. We took plain ropivacaine as an isolated group to avoid the complication of opioids. Hence, our study compared the analgesic efficacy and side effects of equipotent ropivacaine (plain, 0.1%) with or without fentanyl (2.5 μg/mL) vs bupivacaine (plain, 0.0625%) with fentanyl (2.5 μg/mL) combination.
Section snippets
Materials and methods
After institutional ethics committee approval (EC/01/11/212 dated January 18, 2011) and written informed consent from the patient-participants, this prospective, randomized, and double-blind study was performed on 90 American Society of Anesthesiologists I to II adults (age range, 40-60 years; sex, male or female) who underwent bilateral TKR under combined spinal-epidural (CSE) anesthesia administered via a needle-through-needle technique. Exclusion criteria included patient refusal, revision
Demographic and surgery profile
All the recruited 90 participants (n = 90) completed the study. Demographic parameters (age, sex, body weight, height, and BMI), vitals (heart rate, noninvasive blood pressure [mean], and respiratory rate), and duration of surgery were comparable for the 3 study groups (Table 1).
Pain scores
For the first 4 hours postoperatively, pain scores at rest and at motion were comparable across the 3 groups. Thereafter, the median pain scores were significantly lower in “ropivacaine-fentanyl” and
Discussion
Commonly, surgery is followed by acute pain. Notably, correct identification of the type of postoperative pain enables selection of appropriate treatment to bring down patient morbidity. TKR is generally associated with moderate to severe postoperative pain [14]. This prospective double-blind study compared analgesic efficacy, side effects, and patient satisfaction with the use of postoperative PCEA with “ropivacaine 0.1% with/without fentanyl (2.5 μg/mL)” vs “bupivacaine (0.0625%)–fentanyl
Conclusions
- 1.
PCEA administration of ropivacaine-fentanyl combination leads to adequate postoperative analgesia, quantitative reduction of LA drug usage, and heightened satisfaction;
- 2.
The addition of fentanyl to LA solutions (ropivacaine and bupivacaine), except for minor burden (PONV and itching), ensures better postoperative analgesia and patient satisfaction;
- 3.
In comparison to ropivacaine-alone and ropivacaine-fentanyl combinations, bupivacaine plus fentanyl was associated with greater intensity of motor
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