|Year : 2016 | Volume
| Issue : 3 | Page : 398-402
Dexmedetomidine versus fentanyl as adjuvant to epidural 0.5% levobupivacaine for transurethral prostate resection in elderly patients: a comparative evaluation
Kumkum Gupta DA, MD 1, Prashant K Gupta2, Bhawana Rastogi1, Manish Jain1, Deepak Sharma1, Mahesh Narayan Pandey1
1 Department of Anaesthesiology and Critical Care, Subharti Medical College, Swami Vivekanand University, Meerut, Uttar Pradesh, India
2 Department of Radiodiagnosis and Interventional Imaging, Subharti Medical College, Swami Vivekanand University, Meerut, Uttar Pradesh, India
|Date of Submission||17-May-2015|
|Date of Acceptance||20-Mar-2016|
|Date of Web Publication||31-Aug-2016|
108-109, Chanakyapuri, Shastri Nagar, Meerut - 250 004, Uttar Pradesh
Source of Support: None, Conflict of Interest: None
Regional anesthesia is the technique of choice for patients undergoing transurethral resection of the prostate (TURP), but anesthetic management of elderly patients is challenging due to compromised organ function. The present study aimed to evaluate the relative efficacy and safety of dexmedetomidine versus fentanyl in the enhancement of the quality and duration of epidural anesthesia with 0.5% levobupivacaine and hemodynamic stability during TURP in elderly patients.
Patients and methods
Sixty elderly consented patients were randomized into two equal groups of 30 patients each in a double-blind manner. They were given 15 ml of 0.5% levobupivacaine (75 mg) either with 1 ml (50 μg) dexmedetomidine (group LD) or with 1 ml (50 μg) fentanyl (group LF) using an epidural catheter. The primary endpoints were the onset and duration of sensory and motor blockade, duration of sensory analgesia, hemodynamic variability, respiratory adequacy, and any adverse effect.
Demographic data were comparable in both groups. Onset of sensory and motor blockade was faster in patients of group LD than in patients of group LF, with a statistically significant difference (P < 0.05). Duration of motor blockade and sensory analgesia was longer in patients of group LD than in patients of group LF (P < 0.05). Intraoperative heart rate and mean arterial blood pressure were significantly lower in patients of group LD, but no intervention was required. Surgical bleeding was reduced in patients of group LD.
Dexmedetomidine as an adjuvant to epidural levobupivacaine for TURP has shortened onset time of anesthesia and prolonged duration of sensory analgesia. The surgical field vision was improved due to reduced bleeding.
Keywords: dexmedetomidine, epidural anesthesia, fentanyl, levobupivacaine, transurethral resection of the prostate
|How to cite this article:|
Gupta K, Gupta PK, Rastogi B, Jain M, Sharma D, Pandey MN. Dexmedetomidine versus fentanyl as adjuvant to epidural 0.5% levobupivacaine for transurethral prostate resection in elderly patients: a comparative evaluation. Ain-Shams J Anaesthesiol 2016;9:398-402
|How to cite this URL:|
Gupta K, Gupta PK, Rastogi B, Jain M, Sharma D, Pandey MN. Dexmedetomidine versus fentanyl as adjuvant to epidural 0.5% levobupivacaine for transurethral prostate resection in elderly patients: a comparative evaluation. Ain-Shams J Anaesthesiol [serial online] 2016 [cited 2021 Oct 17];9:398-402. Available from: http://www.asja.eg.net/text.asp?2016/9/3/398/189092
| Introduction|| |
Patients who undergo transurethral resection of the prostate (TURP) are often elderly and suffer from cardiac, pulmonary, vascular, and endocrinological disorders. Occasionally, these patients are dehydrated and depleted of essential electrolytes because of long-term diuretic therapy and restricted fluid intake. Anesthetic management of such elderly patients is challenging due to limited organ reserve and compromised organ function, thus requiring a clinically precise skilled anesthetic management to facilitate their early recovery ,.
Regional anesthesia is the anesthetic technique of choice for TURP as it allows monitoring of the patient's mentation and early detection of the signs and symptoms of TURP syndrome or any other complication. It promotes vasodilation and peripheral pooling of blood and thereby reduces the severity of circulatory overload and the incidence of postoperative hypertension and tachycardia, which often accompanies recovery from general anesthesia. At the same time, it provides postoperative analgesia and minimum motor blockade to prevent the complications of deep vein thrombosis, related to delayed immobilization. Thus, regional anesthetic techniques are advantageous due to reduced surgical stress and blood loss .
Levobupivacaine is a local anesthetic amide with longer duration of action with desirable blocking properties of racemic bupivacaine. It has a wider margin of safety due to less systemic and cardiac toxicity potential in comparison with bupivacaine. The recovery and mobilization of the patient are hastened as it showed the clinically relevant advantage of a stronger differentiation between sensory and motor blockade. Recent clinical data have also shown that levobupivacaine is effective and safe for regional anesthetic techniques .
The potency of levobupivacaine may be altered by coadministration with a2 agonist (nonopioid) or opioid analgesics. A synergistic interaction between local anesthetics and epidural adjuvants has been reported. They act independently through different mechanisms. The local anesthetic works at nerve axons and the opioids work at the receptacle site in the spinal cord. a2-Receptor agonists improve the quality and prolong the duration of epidural anesthesia with sensory analgesia. Thus, a combination of local anesthetics with any adjuvant may effectively inhibit multiple areas of neuronal excitability to enhance the efficacy of surgical anesthesia ,.
The present study aimed to evaluate the relative efficacy and safety of dexmedetomidine versus fentanyl as adjuvant to epidural anesthesia with 0.5% levobupivacaine for TURP in elderly patients.
| Patients and methods|| |
After Institutional Ethical Committee approval and written informed consent, this prospective double-blind randomized study was conducted on 60 elderly male patients of ASA physical status II and III aged 65–85 years with a weight of 65–90 kg and a height of 150–170 cm scheduled for elective TURP under epidural anesthesia from August 2013 to December 2014. All patients were subjected to preanesthetic assessment before enrollment for the study. Patients with a history of severe cardiac or pulmonary dysfunction, hepatic or renal diseases, endocrinal or metabolic disorders, bleeding or clotting disorder, deformity of the spinal column, known hypersensitivity to study drugs, infection at local site, patients who refused the technique or were using any drug that modifies pain perception were excluded from the study. Before commencement of epidural anesthesia, all patients were instructed on the methods of sensory and motor assessments.
Patients were randomized according to computer-generated random number table into two comparable equal groups of 30 patients each to receive either 15 ml of 0.5% levobupivacaine with 1 ml (50 μg) of dexmedetomidine (group LD) or 1 ml (50 μg) of fentanyl (group LF) using an epidural catheter in a double-blind manner. A total volume of 16 ml study drug solution was prepared by an anesthesiologist who was blinded to the study protocol and was not involved in intraoperative assessment of patients.
All patients were admitted before the day of the surgery, and fasting of 6 h was ensured. Standard anesthesia monitors for noninvasive blood pressure, heart rate, ECG, and peripheral oxygen saturation (SpO2) were attached and intraoperative monitoring commenced. Preloading with intravenous infusion of lactate Ringer's solution was started at a rate of 5–7 ml/kg before initiation of epidural block and no premedication was given to any patient.
Under all aseptic conditions, epidural anesthesia was administered in sitting position using the midline approach at the L2–L3 or L3–L4 intervertebral space with an 18 G Tuohy needle using the loss of resistance method. With the bevel of the Tuohy needle in cephalic direction, an epidural catheter was inserted 5 cm into the epidural space and secured. The patient was made to lie supine on a horizontal table and a test dose of 3 ml of 2% lidocaine containing 1: 200 000 epinephrine was administered to detect intrathecal or intravenous injection. After 3 min, the patients received study drug solution through an epidural catheter according to the randomization schedule.
The sensory and motor blockade characteristics were assessed after the injection at 2 min intervals until surgical anesthesia was achieved. The segmental level of sensory block to pin prick was assessed bilaterally along the midclavicular line using a short beveled 26 G hypodermic needle. The motor blockade of the lower extremities was evaluated bilaterally using the modified Bromage scale (0–3): 0, full movement, no power impairment, and able to raise straight leg; 1, unable to raise extended leg at the hip but able to flex the knee; 2, unable to flex the knee but able to move ankle joint; and 3, unable to move the hip, knee, or ankle (no motor activity). The surgical anesthesia was considered effective when at least T10 dermatome level was anesthetized. Postoperatively, the sensory and motor block levels were assessed at 30 min intervals until normal sensation returned.
The onset of sensory blockade was defined as the time from epidural injection to the occurrence of sensory block at T10 dermatome level. The onset time of sensory blockade, time taken to achieve maximum sensory block, and time to total regression of sensory block were observed. The onset of motor block was defined as the time from epidural injection to the occurrence of motor block at each scale. The time taken to achieve complete motor blockade and the time to complete recovery from motor blockade were also observed.
Hemodynamic changes in blood pressure and heart rate were observed continuously and recorded at baseline and thereafter at every 5 min intervals during the intraoperative period until the patients were transferred to the postanesthesia recovery room. Supplemental oxygen was administered at a rate of 3 l/min through face mask to all patients during the intraoperative period. For the present study, any change in heart rate and blood pressure was defined as an increase or decrease of more than 20% from the baseline. The hypotension was treated with additional Ringer's lactate solution and a bolus of mephentermine 6 mg. Bradycardia (heart rate <60 beats/min) was treated with intravenous atropine 0.25–0.5 mg. Side effects such as nausea, vomiting, respiratory depression, and postepidural shivering were recorded and managed symptomatically.
Postoperative analgesia was administered on demand through an epidural catheter with 3 ml of local anesthetic drug (0.5% levobupivacaine) and 1 ml (50 μg) of fentanyl, diluted with 6 ml normal saline (total volume of 10 ml) for each top up for both groups. All patients were followed up for any adverse effect until the end of their hospital stay.
At the end of the study, all data were compiled in a tabulated manner and the results were expressed as mean ± SD for the statistical analysis. The sample size was calculated to detect a 30 min difference in the mean duration of sensory and motor blockade between the groups for type 1 error of 0.01 and power of 90%; thus, 60 patients were enrolled keeping the 5% dropout rate. Statistical analysis was performed using Microsoft Excel and Stat graphics centurion for windows using analysis of variance and Student's ‘t’ test for parametric data and the χ2 test was used for nonparametric data. Block characteristics were compared using the Mann–Whitney U test. A ‘P’ value less than 0.05 was considered statistically significant.
| Results|| |
The present study has comparatively evaluated the clinical efficacy and safety of dexmedetomidine versus fentanyl as adjuvant to epidural levobupivacaine 0.5% in 60 elderly consented patients scheduled for elective TURP. There was no protocol deviation, and all patients were successfully operated upon and were cooperative with subsequent assessment. The demographic data and surgical characteristics were comparable in both groups [Table 1].
The hemodynamic characteristics of heart rate and mean arterial blood pressure at baseline with intraoperative changes are shown in [Table 2]. The mean values of heart rate and mean arterial blood pressure did not show significant decline from the base values in patients of group LF, but there was a statistically significant difference in patients of group LD. There was no episode of hypotension in any patient during the study period, but bradycardia (heart rate <60 beats/min) was reported in three (10%) patients of group LD and two (6.6%) patients of group LF and was managed with intravenous atropine (0.25–0.5).
The sensory and motor blockade characteristics of both groups are shown in [Table 3]. The mean onset of adequate sensory analgesia at T10 was faster (11.2 ± 3.6 min) in patients of group LD compared with patients of group LF (13.9 ± 3.7 min). The mean maximal cephalic level for sensory block was not statistically different. The mean time taken to reach the maximal sensory level was less in patients of the dexmedetomidine group, with a statistically significant difference (P = 0.046). The duration of sensory blockade was prolonged in patients of group LD (178.5 ± 8.6 vs. 133.6 ± 10.2 min). The enhancement of duration of sensory analgesia was 45 min, which showed a highly significant difference (P = 0.001).
|Table 3 Sensory and motor blockade profile of epidural anesthesia with levobupivacaine|
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A statistically significant difference was observed between groups for mean onset time for motor blockade of Bromage scale 3. The onset of motor blockade was faster in patients of group LD and was of longer duration (163.5 ± 26 min) than in patients of group LF (116.5 ± 45 min). The duration of motor blockade was shorter than that of sensory analgesia in both groups.
Mild pruritus was observed in five (16%) patients of the fentanyl group, which required no treatment. The ventilatory frequency and peripheral oxygen saturation were comparable between groups. The SpO2 was well maintained above 97% on air in all patients. No patient suffered from postepidural shivering, nausea, vomiting, or respiratory depression. There was no postoperative neurological symptom in any patient.
| Discussion|| |
The present study has evaluated the relative anesthetic efficiency and safety of dexmedetomidine versus fentanyl as adjuvant to epidural 0.5% levobupivacaine for TURP in elderly patients, by assessing the sensory and motor blockade characteristics, intraoperative hemodynamic changes, and postoperative outcome. The present study has demonstrated adequate surgical anesthesia in both groups, with greater hemodynamic stability in patients of the fentanyl group.
Levobupivacaine is safer for regional anesthetic techniques in elderly patients due to its reduced systemic toxicity and greater differentiation between duration of sensory and motor blockade. The low lipid solubility leads to greater sensory motor differentiation by blocking sensory nerve fibers more readily compared with motor fibers. Early recovery of motor function with levobupivacaine is associated with decreased incidence of venous thromboembolism and thus shorter hospitalization ,.
TURP in elderly patients is considered by many as simpler and safer procedure compared with open prostatectomy, but no differences have been reported in mortality rates of patients. Increased morbidity was found in patients when resection time exceeded 90 min, prostate size was greater than 60 g, patient was older than 80 years or was suffering from acute urinary retention. Restlessness and incoherence during TURP are particularly ominous signs of TURP syndrome, which are often caused by subtle pulmonary edema, hypoxemia, and cerebral edema ,.
When evaluating the use of levobupivacaine for epidural anesthesia for lower limbs and abdominal surgery, the first studies reported in the literature showed that clinical profile of the 0.5% levobupivacaine and the 0.75% ropivacaine are similar to that produced by the same concentrations of racemic bupivacaine . Faccenda et al.  reported that levobupivacaine provided less motor block compared with bupivacaine. Peduto et al.  reported that epidural injection of 15 ml of 0.5% levobupivacaine produced similar epidural blockade in patients undergoing lower limb surgery.
The potency of levobupivacaine may be altered by coadministration with a2 agonist (nonopioid analgesic) or opioid analgesics. A synergistic interaction between local anesthetics and epidural adjuvants is reported, but they act independently through different mechanisms. Local anesthetics block the propagation and generation of neural action potential by means of a selective effect on sodium channels, whereas opioids act on the opioid receptors to increase potassium conductance. Fields et al.  showed that dorsal roots (primary afferent tissues) contain opioid binding sites and that fentanyl acts either directly on the spinal nerve or by penetrating the dura mater to act at the spinal roots.
a2-Receptor agonist action is multifactorial. Peripherally, a2 adrenoceptor agonists produce analgesia by reducing the release of norepinephrine and centrally by inhibition of substance P release in the nociceptive pathway at the level of the dorsal root neuron with activation of a2 adrenoceptor in the locus coeruleus. Thus, a combination of local anesthetics and adjuvant may effectively inhibit multiple areas of neuronal excitability to enhance the efficacy of surgical anesthesia. In the present study, the addition of dexmedetomidine or fentanyl with epidural levobupivacaine has accelerated the onset and duration of sensory and motor blockade ,,.
The most significant side effects reported for use of α2 adrenoceptor agonist are bradycardia and hypotension. In the present study, only three (10%) patients suffered from manageable bradycardia, but no patient suffered from hypotension. These side effects were not significant probably because the dexmedetomidine was used in small doses with adequate plasma volume expansion. Pruritus after fentanyl was reported in 16% of patients in the present study, which was only a benign subjective symptom and did not require any intervention treatment expect assurance.
| Conclusion|| |
Epidural 0.5% levobupivacaine with dexmedetomidine showed better clinical profile compared with 0.5% levobupivacaine with fentanyl for transurethral prostatectomy in elderly patients as it hastened the onset of sensory and motor blockade, and extended the duration of surgical anesthesia and analgesia for about 45 min with no respiratory depression. No difference was elicited for cephalic spread between the dexmedetomidine and the fentanyl group. Considering the age and poor cardiorespiratory reserve, the epidural levobupivacaine with dexmedetomidine may be given preference for TURP in elderly population.
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Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3]