Co-administration of pethidine and clonidine: a spinal anaesthetic technique for total hip replacement

Efficacy and safety of intrathecal morphine for analgesia after lower joint arthroplasty: a systematic review and meta-analysis with meta-regression and trial sequential analysis

Widespread adoption of intrathecal morphine into clinical practice is hampered by concerns about its potential side‐effects. We undertook a systematic review, meta‐analysis and trial sequential analysis with the primary objective of determining the efficacy and safety of intrathecal morphine. Our secondary objective was to determine the dose associated with greatest efficacy and safety. We also assessed the impact of intrathecal morphine on respiratory depression. We systematically searched the literature for trials comparing intrathecal morphine with a control group in patients undergoing hip or knee arthroplasty under spinal anaesthesia. Our primary efficacy outcome was rest pain score (0–10) at 8–12 hours; our primary safety outcome was the rate of postoperative nausea and vomiting within 24 hours. Twenty‐nine trials including 1814 patients were identified. Rest pain score at 8–12 hours was significantly reduced in the intrathecal morphine group, with a mean difference (95%CI) of −1.7 (−2.0 to −1.3), p < 0.0001 (19 trials; 1420 patients; high‐quality evidence), without sub‐group differences between doses (p = 0.35). Intrathecal morphine increased postoperative nausea and vomiting, with a risk ratio (95%CI) of 1.4 (1.3–1.6), p < 0.0001 (24 trials; 1603 patients; high‐quality evidence). However, a sub‐group analysis by dose revealed that rates of postoperative nausea and vomiting within 24 hours were similar between groups at a dose of 100 µg, while the risk significantly increased with larger doses (p value for sub‐group difference = 0.02). Patients receiving intrathecal morphine were no more likely to have respiratory depression, the risk ratio (95%CI) being 0.9 (0.5–1.7), p = 0.78 (16 trials; 1173 patients; high‐quality evidence). In conclusion, there is good evidence that intrathecal morphine provides effective analgesia after lower limb arthroplasty, without an increased risk of respiratory depression, but at the expense of an increased rate of postoperative nausea and vomiting. A dose of 100 µg is a ‘ceiling’ dose for analgesia and a threshold dose for increased rate of postoperative nausea and vomiting.

Evaluation of Anesthetic and Analgesic Effects of Intrathecal Administration of Tramadol vs Fentanyl

Objectives:

The aim of this study was to examine the anesthetic and analgesic effects of intrathecal tramadol compared with intrathecal fentanyl added to bupivacaine and that of a placebo added to bupivacaine in patients undergoing elective transurethral procedures.

Methods:

The anesthetic and analgesic efficacy of intrathecal tramadol hydrochloride (HCL) was assessed against a local anesthetic in this prospective, double-blind, randomized study of 146 American Society of Anesthesiologists classification I-III patients who underwent an elective transurethral procedure. A lumbar intrathecal block was performed using bupivacaine heavy 0.5 % combined with either tramadol HCL, fentanyl, or saline for surgery. Each group received 12.5 mg bupivacaine with 50 μg (1 mL) fentanyl, 12.5 mg bupivacaine with 10 mg (1 mL) tramadol, or 12.5 mg bupivacaine with 1 mL preservative-free saline.

Results:

The saline group experienced more pain than patients in the tramadol HCL and fentanyl groups (p<0.05). The mean time to regression of the sensory block to the S1-2 segment was significantly longer in the fentanyl group compared with the tramadol and saline groups (p<0.05). The incidence of complications was similar.

Conclusion:

Fentanyl added to a local anesthetic provided longer postoperative analgesia compared with tramadol added to a local anesthetic.

Effect of intrathecal clonidine versus fentanyl on bupivacaine spinal block in transurethral resection of prostate surgeries

Aims:

Our study aimed at comparing the onset, degree and recovery time of sensory and motor block, the hemodynamic effects and postoperative pain relief using intrathecal bupivacaine alone, bupivacaine along with fentanyl and clonidine.

Materials and Methods:

A total of 90 patients, undergoing transurethral resection of prostate (TURP) surgeries under spinal anesthesia were studied. Patients were randomly divided in a double-blind manner into three groups of 30 patients each. Group A (control) patients given subarachnoid block with 0.5% hyperbaric bupivacaine with 0.5 ml of normal saline. Group B patients were given subarachnoid block with 0.5% hyperbaric bupivacaine along with fentanyl 25 μg. Group C patients were given subarachnoid block with 0.5% hyperbaric bupivacaine 10 mg along with clonidine 30 μg and 0.3 ml of normal saline. After administering the subarachnoid block, vitals were recorded before and after surgery. Level of sensory block, the duration of motor block (DOMB), duration of sensory blockade (DOSB), the quality of postoperative analgesia using linear visual analog scale (VAS), and side effects were evaluated.

Results:

The time required to attain a maximum height of the block was significantly more in Group B as compared to Groups A and C, which was statistically significant. However, there was no statistically significant difference between Groups A and C. The mean DOSB in Groups A, B, and C were 90.83 ± 9.48 min, 135.33 ± 12.59 min, and 155.17 ± 17.49 min, respectively. The mean DOMB in Groups A, B, and C were 83.83 ± 6.52 min, 115.50 ± 14.70 min and 120.67 ± 11.50, respectively. Time of the first request of analgesia in Groups A, B and C in postoperative period were 132.50 ± 21.53 min, 296.00 ± 50.07 min, and 311.83 ± 65.34 min. patients had. VAS was significantly of higher value in Group A than Groups B and C.

Conclusions:

Intrathecal clonidine in a combination of bupivacaine for TURP provides more satisfactory anesthesia and analgesia and has less side effects.

Effect of clonidine and/or fentanyl in combination with intrathecal bupivacaine for lower limb surgery

Background and Aims:

Various adjuncts to local anesthetics have been used with the purpose of improving the quality of subarachnoid block. This randomized double-blind study was conducted to evaluate the efficacy of adding clonidine to bupivacaine and bupivacaine-fentanyl combination.

Material and Methods:

A total of 100 patients scheduled for surgery under spinal anesthesia were randomly allocated into four groups (n = 25 each) to receive intrathecal bupivacaine 7.5 mg plus normal saline 0.5 ml (group BS), intrathecal bupivacaine 7.5 mg, and fentanyl 25 μg (group BF), intrathecal bupivacaine 7.5 mg and clonidine 75 μg (group BC), intrathecal bupivacaine 7.5 mg, clonidine 37.5 μg, and fentanyl 12.5 μg (group BCF). The time of onset and duration of sensory block, highest dermatome level of sensory block, time of onset of motor block, time to complete motor block recovery and duration of spinal anesthesia, intraoperative and postoperative hemodynamics and side effects if any were recorded. VAS, total number of patients who were administered supplemental analgesic in each group and the total amount of supplemental analgesic administered in the next 24 h was quantified and documented in all the groups.

Results:

The time of onset of sensory block (min) in groups BS, BC, BCF, and BF was 10.80 ± 2.26, 10.20 ± 1.00, 10.00 ± 0.00, and 13.80 ± 2.61 respectively, thus onset of sensory block was significantly earlier in groups BC and BCF. Similarly, onset of motor block was also quicker in groups BC and BCF. Time of requirement of supplemental analgesia was 135.20 ± 12.70 min, 199.2 ± 21.92 min, 209.80 ± 26.32 min, and 208.00 ± 26.58 min in groups BS, BF, BC, and BCF respectively. Intraoperative and postoperative changes in heart rate, mean arterial blood pressure, oxygen saturation, and respiratory rate were comparable. Sedation scores were significantly higher in group BC. Pruritus was only observed in groups BF and BCF. Mean nausea vomiting scores were comparable in all groups.

Conclusion:

We conclude that the addition of clonidine in doses of 75 μg and 37.5 μg to low-dose bupivacaine and bupivacaine-fentanyl prolongs the sensory and motor block while increasing the duration of postoperative analgesia without significant side-effects.

Spinal pethidine for elective caesarean section

Pethidine (meperidine) is a unique member of the opioid family. In addition to its analgesic activity, it also has significant local anaesthetic activity. This property enables it to be used as the sole agent for spinal anaesthesia. We describe the successful use of intrathecal pethidine 1 mg/kg for an elective lower segment caesarean section in a patient presumed to be allergic to amide local anaesthetics. There were no significant adverse effects in either the mother or the newborn.

A procedure-specific systematic review and consensus recommendations for analgesia after total hip replacement

Total hip replacement is a major surgical procedure usually associated with significant pain in the early postoperative period. Several anaesthetic and analgesic techniques are in common clinical use for this procedure but, to date, clinical studies of pain after total hip replacement have not been systematically assessed. Using the Cochrane protocol, we have conducted a systematic review of analgesic, anaesthetic and surgical interventions affecting postoperative pain after total hip replacement. In addition to the review, transferable evidence from other relevant procedures and clinical practice observations collated by the Delphi method were used to develop evidence-based recommendations for the treatment of postoperative pain. For primary total hip replacement, PROSPECT recommends either general anaesthesia combined with a peripheral nerve block that is continued after surgery or an intrathecal (spinal) injection of local anaesthetic and opioid. The primary analgesic technique should be combined with a step-down approach using paracetamol plus conventional non-steroidal anti-inflammatory drugs, with strong or weak opioids as required.

Definitions of "respiratory depression" with intrathecal morphine postoperative analgesia: a review of the literature

PURPOSE

To review the postoperative intrathecal morphine (ITM) analgesia literature for their definitions of "respiratory depression" (RD).

SOURCE

Medline (1966 - June Week 5 2001) and reference lists were searched for original studies involving bolus-dose ITM for postoperative analgesia, which used "respiratory depression" or similar terms.

PRINCIPLE FINDINGS

The search identified 209 studies. These were included if ITM use was appropriate (bolus dose, postoperative analgesia) and the term "respiratory depression" was used, which left 96 studies remaining. Forty-four (46%) did not define "RD" despite using this term. A further 24 (25%) defined RD with respiratory rate (RR) alone. Only 28 (29%) defined RD with more than RR alone. There was no statistically significant association between the presence of a definition for RD with study design, study size or publication period. Also, no significant association existed between rigorousness of RD definitions and the above factors.

CONCLUSION

The term "respiratory depression" has no clear definition from a review of the literature on ITM use for postoperative analgesia. While defining RD with bradypnea is superior to having no definition, this is still inadequate. In future research, the consistent use of terms with specific meanings will facilitate understanding the true incidence of ITM's respiratory effects. If "respiratory depression" is used, then an explicit definition of its meaning should be provided. Future research must also address what is clinically significant respiratory impairment from intrathecal opioids, and how to optimally monitor for this. Further delineating their risks vs benefits will allow for more optimal dosing.

Single dose dihydrocodeine for acute postoperative pain

BACKGROUND

Dihydrocodeine is a synthetic opioid analgesic developed in the early 1900s. Its structure and pharmacokinetics are similar to that of codeine and it is used for the treatment of postoperative pain or as an antitussive. It is becoming increasingly important to assess the relative efficacy and harm caused by different treatments. Relative efficacy can be determined when an analgesic is compared with control under similar clinical circumstances.

OBJECTIVES

To quantitatively assess the analgesic efficacy and adverse effects of single-dose dihydrocodeine compared with placebo in randomised trials in moderate to severe postoperative pain.

SEARCH STRATEGY

Published reports were identified from a variety of electronic databases including Medline, Biological Abstracts, Embase, the Cochrane Library and the Oxford Pain Relief Database. Additional studies were identified from the reference lists of retrieved reports.

SELECTION CRITERIA

The following inclusion criteria were used: full journal publication, clinical trial, random allocation of patients to treatment groups, double blind design, adult patients, pain of moderate to severe intensity at baseline, postoperative administration of study drugs, treatment arms which included dihydrocodeine and placebo and either oral or injected (intramuscular or intravenous) administration of study drugs.

DATA COLLECTION AND ANALYSIS

Data collection and analysis: Summed pain intensity and pain relief data over 4-6 hours were extracted and converted into dichotomous information to yield the number of patients obtaining at least 50% pain relief. This was used to calculate relative benefit and number-needed-to-treat for one patient to obtain at least 50% pain relief. Single-dose adverse effect data were collected and used to calculate relative risk and number-needed-to-harm.

MAIN RESULTS

Fifty-two reports were identified as possible randomised trials which assessed dihydrocodeine in postoperative pain. Four reports met the inclusion criteria; all assessed oral dihydrocodeine. Three reports (194 patients) compared dihydrocodeine with placebo and one (120 patients) compared dihydrocodeine (30 mg or 60 mg) with ibuprofen 400 mg. For a single dose of dihydrocodeine 30 mg in moderate to severe postoperative pain the NNT for at least 50% pain relief was 8.1 (95% confidence interval 4.1 to 540) when compared with placebo over a period of 4-6 hours. Pooled data showed significantly more patients to have reported adverse effects with dihydrocodeine 30 mg than with placebo. When compared to ibuprofen 400 mg both dihydrocodeine 30 mg and 60 mg were significantly inferior.

REVIEWER'S CONCLUSIONS

A single 30 mg dose of dihydrocodeine is not sufficient to provide adequate pain relief in postoperative pain. Statistical superiority of ibuprofen 400 mg over dihydrocodeine (30 mg or 60 mg) was shown.

Intrathecal pethidine: pharmacology and clinical applications

Pethidine is the only member of the opioid family that has clinically important local anaesthetic activity in the dose range normally used for analgesia. Pethidine is unique as the only opioid in current use that is effective as the sole agent for spinal anaesthesia. In lower doses, intrathecal pethidine is also an effective analgesic for treating pain in labour. This paper reviews the pharmacology of intrathecal pethidine and clinical experience reported to date. Articles reviewed include those identified by a Medline search using keywords "intrathecal" or "spinal anaesthesia/ anesthesia" and "pethidine" or "meperidine". Reference lists from identified papers were scrutinized to identify further relevant articles.

Segmental effects on motor function following different intrathecal receptor agonists and antagonists in rabbits

BACKGROUND

The occurrence of motor impairment after intrathecal drug administration is infrequently reported in the literature and the methods of determining motor function vary.

METHODS

Motor function was examined in rabbits after a wide dose range of a variety of intrathecally administered opioid agonists, alpha-adrenergic agonists, non-competitive NMDA antagonists, a benzodiazepine agonist, a sigma agonist, paracetamol, isotonic and acidified saline. The opioids, sigma agonist and NMDA antagonists were additionally examined following pretreatment with naloxone. The opioid antagonists naltrindole and MR2266 (delta- and kappa-opioid receptor antagonists, respectively) were administered before the delta agonist and the kappa agonist. The alpha 2-adrenergic antagonist yohimbine was given before administration of dexmedetomidine and xylazine. Motor function was evaluated by a five-point scale of motor impairment ranging from normal function to total paralysis of the hindlegs.

RESULTS

DPDPE (delta agonist), paracetamol, naloxone, naltrindole, yohimbine, isotonic and acidified saline did not affect motor function. MR2266 produced minor motor impairment. The alpha-adrenergic agonist dexmedetomidine reduced motor function slightly and dose independently. The remaining compounds affected motor function in a dose-dependent fashion. High doses of morphine produced hypersensitivity and myoclonus. An irreversible paralysis of the hindlegs was observed following intrathecal administration of the sigma agonist SKF10047 in high doses. Naloxone and MR2266 attenuated the effects of U50488H (kappa agonist).

CONCLUSION

The present results reveal a dose-dependent reduction in motor function after intrathecal administration of some of the investigated compounds. The mechanisms behind these effects appear to be multifactorial.

Anaesthesia and adverse effects after intrathecal pethidine hydrochloride for urological surgery

Anaesthesia, postoperative analgesia and the incidence of adverse effects after intrathecal pethidine hydrochloride 0.50 mg.kg-1 and 0.75 mg.kg-1 were assessed and compared with a conventional technique using isobaric bupivacaine 13.75 mg in patients undergoing transurethral resection of the prostate gland. Sensory and motor block were significantly shorter with both pethidine regimens than with bupivacaine (p < 0.001). Although sensory and motor block were shorter after pethidine 0.50 mg.kg-1 than after pethidine 0.75 mg.kg-1 the difference in duration was clinically insignificant. The incidence of incomplete motor block was significantly greater with pethidine 0.50 mg.kg-1 than with bupivacaine 13.75 mg.kg-1 (p < 0.01). Visual analogue pain scores recorded after the operation were low and were similar in the pethidine groups to those obtained with bupivacaine alone. Mean arterial blood pressure was significantly lower in both pethidine groups compared with the bupivacaine group between 30 and 240 min after intrathecal injection (p < 0.001). However, the within-group reductions in blood pressure were within clinically acceptable limits. The incidences of nausea and emesis were low and emesis occurred in patients in the bupivacaine group only (p < 0.03). Pruritus was seen only in patients receiving pethidine. Intra-operative sedation occurred more often in patients receiving both pethidine 0.50 mg.kg-1 and 0.75 mg.kg-1 compared with patients receiving bupivacaine (p < 0.04). Both pethidine regimens provided acceptable anaesthesia and there were no significant differences between the two regimens in quality of intra-operative anaesthesia, incidence of adverse events or postoperative analgesia.