Intrathecal sufentanil (1.5 microg) added to hyperbaric bupivacaine (0.5%) for elective cesarean section provides adequate analgesia without need for pruritus therapy

Mechanisms and treatment of opioid-induced pruritus: Peripheral and central pathways

BACKGROUND AND OBJECTIVE

Pruritus (also known as itch) is defined as an unpleasant and irritating sensation of the skin that provokes an urge to scratch or rub. It is well known that opioid administration can cause pruritus, which is paradoxical as itch and pain share overlapping sensory pathways. Because opioids inhibit pain but can cause itching. Significant progress has been made to improve our understanding of the fundamental neurobiology of itch; however, much remains unknown about the mechanisms of opioid-induced pruritus. The prevention and treatment of opioid-induced pruritus remains a challenge in the field of pain management. The objective of this narrative review is to present and discuss the current body of literature and summarize the current understanding of the mechanisms underlying opioid-induced pruritus, and its relationship to analgesia, and possible treatment options.

RESULTS

The incidence of opioid-induced pruritus differs with different opioids and routes of administration, and the various mechanisms can be broadly divided into peripheral and central. Especially central mechanisms are intricate, even at the level of the spinal dorsal horn. There is evidence that opioid receptor antagonists and mixed agonist and antagonists, especially μ-opioid antagonists and κ-opioid agonists, are effective in relieving opioid-induced pruritus. Various treatments have been used for opioid-induced pruritus; however, most of them are controversial and have conflicting results.

CONCLUSION

The use of a multimodal analgesic treatment regimen combined with a mixed antagonist and κ agonists, especially μ-opioid antagonists, and κ-opioid agonists, seems to be the current best treatment modality for the management of opioid-induced pruritus and pain.

SIGNIFICANCE

Opioids remain the gold standard for the treatment of moderate to severe acute pain as well as cancer pain. It is well known that opioid-induced pruritus often does not respond to regular antipruritic treatment, thereby posing a challenge to clinicians in the field of pain management. We believe that our review makes a significant contribution to the literature, as studies on the mechanisms of opioid-induced pruritus and effective management strategies are crucial for the management of these patients.

Safety and effectiveness of adding fentanyl or sufentanil to spinal anesthesia: systematic review and meta-analysis of randomized controlled trials

INTRODUCTION

Spinal infusions of either fentanyl or sufentanil have been reported in international reports, articles, and scientific events worldwide. This study aimed to determine whether intrathecal fentanyl or sufentanil offers safety in mortality and perioperative adverse events.

METHODS

MEDLINE (via PubMed), EMBASE, CENTRAL (Cochrane library databases), gray literature, hand-searching, and clinicaltrials.gov were systematically searched. Randomized controlled trials with no language, data, or status restrictions were included, comparing the effectiveness and safety of adding spinal lipophilic opioid to local anesthetics (LAs). Data were pooled using the random-effects models or fixed-effect models based on heterogeneity.

RESULTS

The initial search retrieved 4469 records; 3241 records were eligible, and 3152 articles were excluded after reading titles and abstracts, with a high agreement rate (98.6%). After reading the full texts, 76 articles remained. Spinal fentanyl and sufentanil significantly reduced postoperative pain and opioid consumption, increased analgesia and pruritus. Fentanyl, but not sufentanil, significantly reduced both postoperative nausea and vomiting, and postoperative shivering; compared to LAs alone. The analyzed studies did not report any case of in-hospital mortality related to spinal lipophilic opioids. The rate of respiratory depression was 0.7% and 0.8% when spinal fentanyl or sufentanil was added and when it was not, respectively. Episodes of respiratory depression were rare, uneventful, occurred intraoperatively, and were easily manageable.

CONCLUSION

There is moderate to high quality certainty that there is evidence regarding the safety and effectiveness of adding lipophilic opioids to LAs in spinal anesthesia.

Effects of intrathecal opioids on cesarean section: a systematic review and Bayesian network meta-analysis of randomized controlled trials

PURPOSE

We aimed to compare the beneficial and harmful effects of opioids used as adjuncts to local anesthetics in patients undergoing cesarean section under spinal anesthesia.

METHODS

We searched electronic databases and ClinicalTrials.gov from their inception until March, 2021 without language restrictions. The primary outcome was the complete analgesia duration (Time to VAS > 0). Data were synthesized using the Bayesian random-effects model. Evidence confidence was evaluated using the Confidence In Network Meta-Analysis.

RESULTS

We identified 66 placebo-controlled randomized controlled trials (RCTs) comprising 4400 patients undergoing elective cesarean section. Compared with the placebo, intrathecal opioids (fentanyl, sufentanil, and morphine) significantly prolonged the analgesia duration by 96, 96, and 190 min, respectively (mean difference). Despite morphine ranking first, opioid efficacy was similar; the results were inconsistent with respect to other analgesic outcomes. Except for diamorphine, all opioids were associated with significant increases in the pruritus incidence. Sufentanil and morphine were associated with increases in the respiratory depression incidence.

CONCLUSIONS

We confirmed that intrathecal opioids benefit postoperative analgesia. Although morphine seems to be the most appropriate agent, some results were inconsistent, and the evidence confidence was often moderate or low, especially for adverse outcomes. Well-designed RCTs with an evidence-based approach are imperative for determining the most appropriate opioid for cesarean sections.

Adjuvants to local anesthetics: Current understanding and future trends

Although beneficial in acute and chronic pain management, the use of local anaesthetics is limited by its duration of action and the dose dependent adverse effects on the cardiac and central nervous system. Adjuvants or additives are often used with local anaesthetics for its synergistic effect by prolonging the duration of sensory-motor block and limiting the cumulative dose requirement of local anaesthetics. The armamentarium of local anesthetic adjuvants have evolved over time from classical opioids to a wide array of drugs spanning several groups and varying mechanisms of action. A large array of opioids ranging from morphine, fentanyl and sufentanyl to hydromorphone, buprenorphine and tramadol has been used with varying success. However, their use has been limited by their adverse effect like respiratory depression, nausea, vomiting and pruritus, especially with its neuraxial use. Epinephrine potentiates the local anesthetics by its antinociceptive properties mediated by alpha-2 adrenoreceptor activation along with its vasoconstrictive properties limiting the systemic absorption of local anesthetics. Alpha 2 adrenoreceptor antagonists like clonidine and dexmedetomidine are one of the most widely used class of local anesthetic adjuvants. Other drugs like steroids (dexamethasone), anti-inflammatory agents (parecoxib and lornoxicam), midazolam, ketamine, magnesium sulfate and neostigmine have also been used with mixed success. The concern regarding the safety profile of these adjuvants is due to its potential neurotoxicity and neurological complications which necessitate further research in this direction. Current research is directed towards a search for agents and techniques which would prolong local anaesthetic action without its deleterious effects. This includes novel approaches like use of charged molecules to produce local anaesthetic action (tonicaine and n butyl tetracaine), new age delivery mechanisms for prolonged bioavailability (liposomal, microspheres and cyclodextrin systems) and further studies with other drugs (adenosine, neuromuscular blockers, dextrans).

Sufentanil and Bupivacaine Combination versus Bupivacaine Alone for Spinal Anesthesia during Cesarean Delivery: A Meta-Analysis of Randomized Trials

Objective

The addition of lipophilic opioids to local anesthetics for spinal anesthesia has become a widely used strategy for cesarean anesthesia. A meta-analysis to quantify the benefits and risks of combining sufentanil with bupivacaine for patients undergoing cesarean delivery was conducted.

Methods

A comprehensive literature search without language or date limitation was performed to identify clinical trials that compared the addition of sufentanil to bupivacaine with bupivacaine alone for spinal anesthesia in healthy parturients choosing cesarean delivery. The Q and I² tests were used to assess heterogeneity of the data. Data from each trial were combined using relative ratios (RRs) for dichotomous data or weighted mean differences (WMDs) for continuous data and corresponding 95% confidence intervals (95% CIs) for each trial. Sensitivity analysis was conducted by removing one study a time to assess the quality and consistency of the results. Begg’s funnel plots and Egger’s linear regression test were used to detect any publication bias.

Results

This study included 9 trials containing 578 patients in the final meta-analysis. Sufentanil addition provided a better analgesia quality with less breakthrough pain during surgery than bupivacaine alone (RR = 0.10, 95% CI 0.06 to 0.18, P < 0.001). Sensory block onset time was shorter and first analgesic request time was longer in sufentanil added group compared with the bupivacaine-alone group (WMD = −1.0 min, 95% CI −1.5 to −0.58, P < 0.001 and WMD = 133 min, 95% CI 75 to 213, P < 192, respectively). There was no significant difference in the risk of hypotension and vomiting between these two groups. But pruritus was more frequentely reported in the group with sufentanil added (RR = 7.63, 95% CI 3.85 to 15.12, P < 0.001).

Conclusion

Bupivacaine and sufentanil combination is superior to that of bupivacaine alone for spinal anesthesia for cesarean delivery in analgesia quality. Women receiving the combined two drugs had less breakthrough pain, shorter sensory block onset time, and longer first analgesic request time. However, the addition of sufentanil to bupivacaine increased the incidence of pruritus.

Comparison of intrathecal levobupivacaine combined with sufentanil, fentanyl, or placebo for elective caesarean section: a prospective, randomized, double-blind, controlled study

Background

The addition of opioids to local anesthetics contributes to the quality of spinal anesthesia and postoperative analgesia.

Objective

In our prospective, randomized, double-blind, controlled study, our aim was to compare the effect of low-dose sufentanil plus levobupivacaine or a fentanyl plus levobupivacaine mixture on anesthesia quality, block characteristics, newborn and mother well-being, surgeon satisfaction, and duration of postoperative analgesia.

Methods

Ninety-three patients were randomized into 3 groups (n = 31). Patients in Group C received 0.5% levobupivacaine (2.2 ± 0.2 mL), Group S received 2.5 µg sufentanil plus 0.5% levobupivacaine (2.2 ± 0.2 mL), and Group F received 10 µg fentanyl plus 0.5% levobupivacaine (2.2 ± 0.2 mL) intrathecally completed to a volume of 3 mL with the addition of saline in all groups. Patients’ demographics, sensory and motor block characteristics, hemodynamics, Apgar scores, umbilical blood gas values, maternal side effects, surgeon satisfaction score, time to first analgesia requirement, and additional analgesic use within 24 hours were recorded.

Results

In Group S and Group F, target levels of sensory and motor block were achieved more rapidly (P < 0.001). The hemodynamic values were lower (P < 0.05), and the duration of sensory blockade and the time of first analgesic requirement were longer (P < 0.001) in Group S. Additional analgesic requirement during first 24-hour period was lowest in Group S, and highest in Group C (P < 0.001). Apgar scores and umbilical blood gas samples were similar between groups. Postoperative pruritus was more frequent in Group S (P < 0.001) and surgeon satisfaction score was significantly lower in Group C (P = 0.003).

Conclusions

We suggest that the addition of sufentanil and fentanyl to intrathecal levobupivacaine during caesarean section surgery is more effective than the administration of levobupivacaine alone. The addition of sufentanil to levobupivacaine allowed rapid onset time for sensory and motor block levels. It also extended the duration of postoperative analgesia and led to a decrease in total analgesic requirement. ClinicalTrials.gov identifier: NCT01858090.

Comparison of clinical effects according to the dosage of sufentanil added to 0.5% hyperbaric bupivacaine for spinal anesthesia in patients undergoing cesarean section

Background

Subarachnoid block is a widely used technique for cesarean section. To improve the quality of analgesia and prolong the duration of analgesia, addition of intrathecal opioids to local anesthetics has been encouraged. We compared the effects of sufentanil 2.5 µg and 5 µg, which were added to intrathecal hyperbaric bupivacaine.

Methods

We enrolled 105 full term parturients were randomly divided into 3 groups: Group 1 (control), Group 2 (sufentanil 2.5 µg), and Group 3 (sufentanil 5 µg). In every group, 0.5% heavy bupivacaine was added according to the adjusted dose regimen. We determined the maximum level of sensory block and motor block, the quality of intraoperative analgesia, the duration of effective analgesia and side effects.

Results

There were no significant differences among the 3 groups in the maximum level of the sensory block and motor block. Recovery rate of the sensory block, however, was significantly slower in Group 3 than Group 1. Quality of intraopertive analgesia, muscle relaxation, and duration of effective analgesia were enhanced by increasing the dosage of intrathecal sufentanil. Frequencies of hypotension, maximum sedation level, and pruritus were directly related to the dosage of intrathecal sufentanil, whereas nausea and vomiting occurred only in the groups using sufentanil.

Conclusions

The addition of sufentanil 2.5 µg for spinal anesthesia provides adequate intraoperative analgesia and good postoperative analgesia with minimal adverse effects on the mother.

Comparison of bupivacaine alone and in combination with sufentanil in patients undergoing arthroscopic knee surgery

PURPOSE

One disadvantage of spinal anesthesia using bupivacaine is the relatively short duration of action. Combining it with opioids can increase its analgesic effects. It was aimed to analyze the effectiveness and the side effects of bupivacaine alone and in combination with sufentanil in arthroscopic knee surgery during unilateral spinal anesthesia.

METHODS

This is a prospective, randomized, double-blind trial. Fifty patients undergoing unilateral arthroscopic knee surgery were enrolled in this study. The patients were assigned into two groups to receive either 10 mg of 0.5% hyperbaric bupivacaine (Group I) or 5 mg of 0.5% hyperbaric bupivacaine combined with 2.5 μg sufentanil (Group II) to obtain unilateral spinal anesthesia.

RESULTS

The time for sensorial block to reach level T10 was 6.3 ± 1.7 min in Group I and 4.8 ± 1.6 min in Group II (P < 0.05). Complete motor block was obtained at the 10th min in 16 patients in Group I (P < 0.005), and the duration of the motor block was lower in Group II (4.9 ± 2.2 h and 2.0 ± 1.1 h, P < 0.001). Bradycardia was encountered in 8 patients in Group I and in 1 patient in Group II (P < 0.05). No differences were encountered regarding other side effects. During the postoperative 24 h, 5 patients in Group I and 3 patients in Group II required analgesic drugs (n.s.). There was not any significant difference between groups with regard to first analgesic request time (8.3 ± 2.4 and 9.0 ± 2.3 h, n.s.).

CONCLUSIONS

This study showed that combining lower dose bupivacaine with sufentanil provided faster onset of sensorial block and lower risk of motor block in unilateral spinal anesthesia for arthroscopic knee surgery.

Comparison of fentanyl and sufentanil added to 0.5% hyperbaric bupivacaine for spinal anesthesia in patients undergoing cesarean section

BACKGROUND

Subarachnoid block is widely used for cesarean section due to the rapid induction, the complete analgesia, the low failure rate and the prevention of aspiration pneumonia. The addition of intrathecal opioids to local anesthetics seems to improve the quality of analgesia & prolong the duration of analgesia. Therefore we compared the effects of fentanyl 20 µg and sufentanil 2.5 µg, which were added to intrathecal hyperbaric bupivacaine.

METHODS

SEVENTY TWO HEALTHY TERM PARTURIENTS WERE RANDOMLY DIVIDED INTO THREE GROUPS: Group C (control), Group F (fentanyl 20 µg) and Group S (sufentanil 2.5 µg). In every group, 0.5% heavy bupivacaine was added according to the adjusted dose regimen by Harten et al. We observed the maximal level of the sensory block and motor block, the quality of intraoperative analgesia, the duration of effective analgesia and the side effects.

RESULTS

There were significant differences between the control and the fentanyl 20 µg and sufentanil 2.5 µg groups for the degree of muscle relaxation, the quality of intraoperative analgesia, the maximal sedation level and the duration of effective analgesia. The frequencies of side effects such as nausea and pruritis in the opioid groups were higher than those in the control group. But there were no differences between fentanyl 20 µg and sufentanil 2.5 µg for the frequencies of nausea and pruritis.

CONCLUSIONS

The addition of fentanyl 20 µg or sufentanil 2.5 µg for spinal anesthesia provides adequate intraoperative analgesia without significant adverse effects on the mother and neonate.

Local anaesthetic adjuvants: neuraxial versus peripheral nerve block

PURPOSE OF REVIEW

To present a review of the literature on the importance and the clinical characteristics relevant to adjuvants added to local anaesthetics in neuraxial and peripheral nerve blocks.

RECENT FINDINGS

In neuraxial anaesthesia, both opioids and alpha-2 receptor agonists have beneficial effects. Intrathecally, fentanyl and sufentanil not only improve the postoperative analgesia but also make it possible to allow a decrease in the local anaesthetic dose. When clonidine or dexmedetomidine was added to intrathecal local anaesthetics, the regression of sensory, motor block increased dose-dependently and postoperative analgesia was prolonged. The potency of intrathecal clonidine: dexmedetomidine seems to be 10: 1. In peripheral nerve block, when opioid was combined with local anaesthetics, no increased improvement in analgesia was reported in comparison with systemic controls in most of the studies, except buprenorphine. Also clonidine is controversial as an analgesic adjuvant. Special factors, such as type of local anaesthetics, block of upper or lower limb, are important for its the beneficial effect. Other adjuvants, except neuraxial low-dose neostigmine, are of minor importance.

SUMMARY

Opioids and alpha-2 receptor agonists are important as neuraxial adjuvants to improve the quality of peroperative and postoperative analgesia in high-risk patients and in ambulatory procedures. In peripheral nerve blocks, however, some benefit is found only when clonidine is added to local anaesthetics under certain circumstances.

Comparison of high- and low-dose intrathecal morphine for spinal fusion in children

BACKGROUND

The purpose of this prospective study was to assess the blood-sparing effect, the quality of analgesia, and the incidence of side-effects of a low-dose regime of intrathecal opioids (ITO) when compared with those of a high-dose regime in scoliosis surgery in children.

METHODS

Forty-six children were randomly included into one of the three groups to receive morphine 5 microg kg(-1) plus sufentanil 1 microg kg(-1) [low-dose intrathecal opioid (LITO)], morphine 15 microg kg(-1) plus sufentanil 1 microg kg(-1) [high-dose intrathecal opioid (HITO)] intrathecally, or no intrathecal opioid. Postoperative analgesia was provided by i.v. opioids. Intraoperative blood loss, postoperative quality of analgesia, opioid requirements, and the incidence of side-effects were recorded for 3 days.

RESULTS

Intraoperative blood loss was significantly reduced by ITOs [LITO: 41.4 (sd 18.8) ml kg(-1); HITO: 37.5 (6.9) ml kg(-1); control: 76.9 (15.3) ml kg(-1), P<0.001], with no difference between the two intrathecal opioid groups. Mean pain scores on the day of surgery were lower in both intrathecal opioid groups (LITO: 2.2 and HITO: 2.1) when compared with the control group (4.1, P<0.03) and opioid consumption was significantly decreased [LITO: 304.3 (65.0) microg kg(-1); HITO: 224.1 (51.8) microg kg(-1); control: 667.7 (89.5) microg kg(-1), P<0.002]. Side-effects of intrathecally administered opioids were similarly frequent in all groups.

CONCLUSIONS

Intrathecal administration of opioids significantly reduces blood loss and postoperative opioid demand, thereby showing side-effects comparable with the control group. These effects were already seen with the low-dose regimen and high dose did not further improve efficacy.