Dose-Ranging Effects of Intrathecal Epinephrine on Anesthesia/Analgesia: A Meta-Analysis and Metaregression of Randomized Controlled Trials

Prolongation of spinal duration by escalating doses of intrathecal epinephrine in lower limb arthroplasty

Aim: The optimal dose of low-dose intrathecal epinephrine in the absence of intrathecal opioids is unknown. Materials & methods: Prospective, randomized, double blind clinical trial of patients undergoing lower limb arthroplasties. The primary end point was spinal block duration measured via motor and sensory block duration. Results: 30 patients undergoing lower limb arthroplasty were randomized into one of six groups with varying intrathecal epinephrine doses 0-100 mcg. There was a direct linear effect between motor block duration and intrathecal epinephrine dose with higher doses being associated with longer block duration (p = 0.011). Mean motor block duration was 3.74 ± 1.13, 3.36 ± 0.47, 3.39 ± 0.60, 4.06 ± 0.98 and 5.20 ± 1.41 h for the EPI0, EPI25, EPI50, EPI75 and EPI100 groups respectively. Conclusion: This study reveals that low-dose intrathecal epinephrine (75-100 mcg) in the absence of intrathecal opioids can be reliably used to prolong motor block duration in lower limb arthroplasty. Clinical Trial Registration: NCT02619409 (ClinicalTrials.gov).

Intrathecal dopamine and serotonin enhance motor and nociceptive blockades of lidocaine in rats

The study examined the effect of intrathecal injection of dopamine (serotonin) and/or lidocaine. Intrathecal injections of dopamine (serotonin or epinephrine), lidocaine, or their combination were carried out in male Sprague Dawley rats. Neurobehavioral examinations (motor and nociceptive reactions) were performed before and after spinal injection. Intrathecal serotonin (1.5 μmol), dopamine (2.5 μmol), epinephrine (1:40000), and lidocaine (0.75 μmol) produced 29%, 33%, 29%, and 54% nociceptive blockade, whereas serotonin (1.5 μmol), dopamine (2.5 μmol), or epinephrine (1:40000) produced a longer duration of nociceptive blockade than lidocaine (0.75 μmol) (P < 0.05). Serotonin (1.5 μmol), dopamine (1.25 and 2.5 μmol), or epinephrine (1:40000 and 1:80000) prolonged the duration and increased the potency of spinal motor and nociceptive blockades of lidocaine (50% effective dose, ED50) (P < 0.05). The motor and nociceptive blockades caused by lidocaine (ED50) plus dopamine (2.5 μmol) or lidocaine (ED50) plus epinephrine (1:40000) were more outstanding than lidocaine (ED50) plus serotonin (0.75 μmol) (P < 0.05). Our study provides evidence that intrathecal dopamine or serotonin produces spinal nociceptive blockade dose-dependently. Dopamine and serotonin are less potent than lidocaine in inducing spinal nociceptive blockade. When mixed with lidocaine solution, dopamine or serotonin improves spinal motor and nociceptive blockades. The motor and nociceptive blockade caused by lidocaine (ED50) plus dopamine (2.5 μmol) is similar to that caused by lidocaine (ED50) plus epinephrine (1:40000).

Effects of Adding Intrathecal Epinephrine to Spinal Anesthesia on Anesthesia-Related Cesarean Delivery Outcomes: Should We Reconsider Its Use?

BACKGROUND

 Intrathecal epinephrine is used to increase the duration of spinal anesthesia for amenable surgical procedures anticipated to require additional time; however, in the ambulatory setting, it is associated with a prolonged time to post-anesthesia care unit (PACU) discharge. The current study's authors hypothesized that adding intrathecal epinephrine to spinal anesthesia for cesarean delivery would be associated with a dose-dependent prolonged post-anesthesia unit length of stay.

METHODS

A single-center, retrospective study of patients undergoing repeat cesarean delivery under spinal anesthesia from 2011 to 2015 was conducted. Patients received spinal bupivacaine 12 mg, morphine 150 mcg, and fentanyl 15 mcg with no-epinephrine, 100 mcg, or 200 mcg of epinephrine. The primary outcome was recovery room length of stay. Secondary outcomes were surgical duration, intraoperative vasopressor use, perioperative opioids, and antiemetic use.

RESULTS

 Data were analyzed for 1,362 patients. Median recovery room stay was 123 min (interquartile range, 100 to 150) and was not different among groups. More women receiving epinephrine 200 mcg had ≥2 prior cesarean deliveries compared with no-epinephrine or 100 mcg. No significant differences in surgical duration or intraoperative opioids were identified among the groups. Median intraoperative vasopressor use was increased by 225 mcg of phenylephrine equivalents (99% CI, 25 mcg to 430 mcg) in the 100 mcg group and 250 mcg of phenylephrine equivalents in the 200 mcg group (99% CI, 75 mcg to 500 mcg) compared to no-epinephrine (P<0.001). Recovery room antiemetic and opioid analgesic administration were not different among groups.

CONCLUSIONS

 Based on the results of this study, the addition of intrathecal epinephrine for women undergoing cesarean delivery increases intraoperative vasopressor use but does not prolong PACU length of stay, reduce intraoperative opioids, or increase antiemetic requirements postoperatively. The current study also demonstrated that surgical duration times were not different among the no-epinephrine, 100 mcg, and 200 mcg epinephrine groups.

Hemodynamic protective effects of epinephrine containing saline irrigation in biportal endoscopic lumbar surgery

During endoscopic orthopedic surgery, epinephrine mixed with irrigation saline is frequently used to improve visualization. By monitoring hemodynamic parameters throughout the procedure, we intended to discover the hemodynamic effect of epinephrine between the normal saline irrigation fluid without epinephrine group (NS) and normal saline irrigation fluid with epinephrine group (EPI). Patients who underwent 1-level lumbar decompression or discectomy surgery without fusion between August 2019 and July 2020 were reviewed retrospectively. The hemodynamic parameters were compared between the NS group and EPI group. As a second endpoint, the incidence of hypotension and hypertension events, expected blood loss, postoperative nausea and vomiting and postoperative epidural hematoma were compared between the 2 groups. The 2 groups were homogeneous in terms of age, sex, weight, height, body mass index (BMI), ASA physical status (ASA PS), and diagnosis. The incidence of hypotension events (67.2 % in the NS group, 45.7 % in the EPI group, P =.015) and severe hypotension events (51.7 % in the NS group, 28.6 % in the EPI group, P = .015) were less frequent in the EPI group. Only epinephrine had a significant protective effect through a multivariable analysis (P = .027, OR = 2.361) and in severe hypotension events, only epinephrine had a significant protective effect through a multivariable analysis (P = .011, OR = 2.818), and EBL was the risk factor through a multivariable analysis (P = .016, OR = 1.002) We believe that the addition of epinephrine to irrigation saline has hemodynamic protective effects in patients who underwent endoscopic lumbar surgery.

The Options for Neuraxial Drug Administration

Neuraxial drug administration, i.e., the injection of drugs into the epidural or intrathecal space to produce anesthesia or analgesia, is a technique developed more than 120 years ago. Today, it still is widely used in daily practice in anesthesiology and in acute and chronic pain therapy. A multitude of different drugs have been introduced for neuraxial injection, only a part of which have obtained official approval for that indication. A broad understanding of the pharmacology of those agents is essential to the clinician to utilize them in a safe and efficient manner. In the present narrative review, we summarize current knowledge on neuraxial anatomy relevant to clinical practice, including pediatric anatomy. Then, we delineate the general pharmacology of neuraxial drug administration, with particular attention to specific aspects of epidural and intrathecal pharmacokinetics and pharmacodynamics. Furthermore, we describe the most common clinical indications for neuraxial drug administration, including the perioperative setting, obstetrics, and chronic pain. Then, we discuss possible neurotoxic effects of neuraxial drugs, and moreover, we detail the specific properties of the most commonly used neuraxial drugs that are relevant to clinicians who employ epidural or intrathecal drug administration, in order to ensure adequate treatment and patient safety in these techniques. Finally, we give a brief overview on new developments in neuraxial drug therapy.

Peripartum anesthetic management of patients with inflammatory bowel disease, a retrospective case-control study

OBJECTIVE

Inflammatory bowel diseases (IBD) are a group of pathologies associated with an increased rate of abortions, premature deliveries, cesarean sections and other morbidity during the peripartum period. The objective of this retrospective study was to investigate the anesthetic management for delivery of women with IBD.

MATERIAL AND METHODS

The records of patients with IBD, who delivered at our Center, were obtained for data which included anesthetic and obstetric management as well as neonatal outcome. Five subgroups were defined based on mode of delivery, presence or absence of epidural in normal vaginal delivery (NVD) and urgency of cesarean section, each of which was compared with control groups of healthy parturients in the same period. Additionally, the rate of cesarean sections and the use of epidural analgesia for NVD were compared with the general obstetric population of our center in the same period.

RESULTS

107 patients with IBD who delivered at our center were studied. The rates of cesarean sections and emergency cesarean sections were significantly higher compared to the general population. However, the rate of instrumental delivery and of epidural analgesia use for NVD were similar. Among those who underwent cesarean sections, no significant differences were found in anesthesia type, surgery duration, number of complications, type of monitoring or postoperative management compared to the control group.

CONCLUSION

Peripartum anesthetic management of patients with IBD does not differ significantly from that of parturients without it. Anesthesiologists can plan their anesthesia in a similar way as they do in healthy parturients.

Effect of Two Different Doses of Dexmedetomidine as Adjuvant in Bupivacaine Induced Subarachnoid Block for Elective Abdominal Hysterectomy Operations: A Prospective, Double-blind, Randomized Controlled Study

OBJECTIVES

Improvements in perioperative pain management for lower abdominal operations has been shown to reduce morbidity, induce early ambulation, and improve patients' long-term outcomes. Dexmedetomidine, a selective alpha-2 agonist, has recently been used intrathecally as adjuvant to spinal anesthesia to prolong its efficacy. We compared two different doses of dexmedetomidine added to hyperbaric bupivacaine for spinal anesthesia. The primary endpoints were the onset and duration of sensory and motor block, and duration of analgesia.  .

METHODS

A total of 100 patients, aged 35-60 years old, assigned to have elective abdominal hysterectomy under spinal anesthesia were divided into two equally sized groups (D5 and D10) in a randomized, double-blind fashion. The D5 group was intrathecally administered 3ml 0.5% hyperbaric bupivacaine with 5µg dexmedetomidine in 0.5ml of normal saline and the D10 group 3ml 0.5% bupivacaine with 10µg dexmedetomidine in 0.5ml of normal saline. For each patient, sensory and motor block onset times, block durations, time to first analgesic use, total analgesic need, postoperative visual analogue scale (VAS) scores, hemodynamics, and side effects were recorded.  .

RESULTS

Although both groups had a similar demographic profile, sensory and motor block in the D10 group (p<0.050) was earlier than the D5 group. Sensory and motor block duration and time to first analgesic use were significantly longer and the need for rescue analgesics was lower in the D10 group than the D5 group. The 24-hour VAS score was significantly lower in the D10 group (p<0.050). Intergroup hemodynamics were comparable (p>0.050) without any appreciable side effects.  .

CONCLUSION

Spinal dexmedetomidine increases the sensory and motor block duration and time to first analgesic use, and decreases analgesic consumption in a dose-dependent manner.

Single-dose systemic acetaminophen to prevent postoperative pain: a meta-analysis of randomized controlled trials

OBJECTIVES

The effect of a single-dose systemic acetaminophen to treat postoperative pain has been previously quantified, but the effect of systemic acetaminophen to prevent postoperative pain is currently not well defined. The preventive analgesic effect of acetaminophen has yet to be quantified in a meta-analysis. The objective of the current investigation was to evaluate the effect of a single preventive dose of systemic acetaminophen on postoperative pain outcomes.

MATERIALS AND METHODS

A wide search was performed to identify randomized controlled trials that evaluated the effects of a single dose of systemic acetaminophen on pain outcomes in a large variety of surgical procedures. Meta-analysis was performed using a random-effect model.

RESULTS

Eleven randomized clinical trials evaluating 740 patients were included in the analysis. The weighted mean difference (95% confidence interval [CI]) of the combined effects favored acetaminophen over control for early pain at rest (≤4 h, -1.1 (-2.0 to -0.2)) and early pain at movement (24 h, -1.9 (-2.8 to -1.0)) Postoperative opioid consumption was decreased in the systemic acetaminophen group compared with control. Weighted mean difference (95% CI) of -9.7 (-13.0 to -6.4) mg morphine intravenous equivalents systemic acetaminophen also reduced postoperative nausea and vomiting compared with control, odds ratio (95% CI) of 0.25 (0.13 to 0.47), numbers needed to treat (95% CI)=3.3 (2.3 to 5.9).

DISCUSSION

Systemic acetaminophen, when used as a single-dose preventive regimen, is an effective intervention to reduce postoperative pain. It also reduces postoperative nausea and/or vomiting. Doses >1 g were not associated with greater reduction in pain outcomes.

Effect of different doses of dexmedetomidine as adjuvant in bupivacaine -induced subarachnoid block for traumatized lower limb orthopaedic surgery: a prospective, double-blinded and randomized controlled study

BACKGROUND AND AIMS

Improved pain management for blunt trauma to the lower extremity has shown to reduce morbidity, induce early ambulation and improve long-term outcomes. Dexmedetomidine; a selective α-2 agonist; has recently been used intrathecally in different doses to prolong spinal anaesthesia. We evaluated the effect of adding two different doses of dexmedetomidine to hyperbaric bupivacaine for spinal anaesthesia. The primary endpoints were the onset and duration of sensory, motor block and duration of analgesia.

MATERIALS AND METHODS

Eighty patients, (20-60yrs) posted for elective lower limb orthopedic surgery of traumatic origin under spinal anaesthesia were divided into 2 equal groups (Group D5&D10) in a randomized, double-blind fashion. In this prospective parallel group study, group D5(n=40) 3ml 0.5% hyperbaric bupivacaine+5μg dexmedetomidine in 0.5 ml of normal saline and group D10 (n=40) 3ml 0.5% bupivacaine+10μg dexmedetomidine in 0.5 ml of normal saline were administered intrathecally. Sensory and motor block onset times and block durations, time to first analgesic use, total analgesic need, postoperative VAS, hemodynamics and side effects were recorded for each patient.

RESULTS

Though with similar demographic profile in both groups, sensory and motor block in group D10(p<0.05) was earlier than group D5. Sensory, motor block duration and time to first analgesic use were significantly longer and the need for rescue analgesics was lower in group D10(p<0.05) than D5. 24 h VAS score was significantly lower in group D10(p<0.05). Intergroup hemodynamics was comparable (p>0.05) without any appreciable side effects.

CONCLUSION

Spinal dexmedetomidine increases the sensory, motor block duration and time to first analgesic use, and decreases analgesic consumption in a dose-dependent manner.

Perineural dexamethasone to improve postoperative analgesia with peripheral nerve blocks: a meta-analysis of randomized controlled trials

Background. The overall effect of perineural dexamethasone on postoperative analgesia outcomes has yet to be quantified. The main objective of this quantitative review was to evaluate the effect of perineural dexamethasone as a nerve block adjunct on postoperative analgesia outcomes. Methods. A systematic search was performed to identify randomized controlled trials that evaluated the effects of perineural dexamethasone as a block adjunct on postoperative pain outcomes in patients receiving regional anesthesia. Meta-analysis was performed using a random-effect model. Results. Nine randomized trials with 760 subjects were included. The weighted mean difference (99% CI) of the combined effects favored perineural dexamethasone over control for analgesia duration, 473 (264 to 682) minutes, and motor block duration, 500 (154 to 846) minutes. Postoperative opioid consumption was also reduced in the perineural dexamethasone group compared to control, -8.5 (-12.3 to -4.6) mg of IV morphine equivalents. No significant neurological symptoms could have been attributed to the use of perineural dexamethasone. Conclusions. Perineural dexamethasone improves postoperative pain outcomes when given as an adjunct to brachial plexus blocks. There were no reports of persistent nerve injury attributed to perineural administration of the drug.

The effects of perineural versus intravenous dexamethasone on sciatic nerve blockade outcomes: a randomized, double-blind, placebo-controlled study

BACKGROUND

Perineural dexamethasone has been investigated as an adjuvant for brachial plexus nerve blocks, but it is not known whether the beneficial effect of perineural dexamethasone on analgesia duration leads to a better quality of surgical recovery. We hypothesized that patients receiving dexamethasone would have a better quality of recovery than patients not receiving dexamethasone. We also sought to compare the effect of perineural with that of IV dexamethasone on block characteristics.

METHODS

Patients undergoing elective ankle and foot surgery were recruited over a 9-month period. Patients received ultrasound-guided sciatic nerve blocks by using 0.5% bupivacaine with epinephrine 1:300,000 (0.45 mL/kg) and were randomized into 3 groups: group 1 = perineural dexamethasone 8 mg/2 mL with 50 mL IV normal saline, group 2 = perineural saline/2 mL with IV 8 mg dexamethasone in 50 mL normal saline, and group 3 = perineural saline/2 mL with 50 mL normal saline. The primary outcome was the global score in the quality of recovery (QoR-40). The secondary outcomes included analgesia duration, opioid consumption, patient satisfaction, numeric pain rating scores, and postoperative neurologic symptoms.

RESULTS

Eighty patients were randomized, and 78 patients completed the study protocol. There was no improvement in the global QoR-40 score at 24 hours between the perineural dexamethasone and saline, median (97.5% CI) difference of -3 (-7 to 3); IV dexamethasone and saline, median difference of -1 (-8 to 5); or perineural dexamethasone and IV dexamethasone median difference of -2 (-6 to 5). Analgesia duration (P < 0.001) and time to first toe movement (P < 0.001) were prolonged by perineural dexamethasone compared with saline. IV dexamethasone prolonged time to first toe movement compared with saline (P = 0.008) but not analgesia duration (P = 0.18). There was no significant difference in the time to first toe movement or analgesia duration between the perineural and IV dexamethasone groups. Postoperative opioid consumption was not different among study groups. Self-reported neurologic symptoms at 24 hours were not different among perineural dexamethasone (17, 63%), IV dexamethasone (10, 42%), or normal saline (8, 30%) (P = 0.31). All postoperative neurologic sequelae were resolved by 8 weeks.

CONCLUSIONS

Preoperative administration of IV and perineural dexamethasone compared with saline did not improve overall QoR-40 or decrease opioid consumption but did prolong analgesic duration in patients undergoing elective foot and ankle surgery and receiving sciatic nerve block. Given the lack of clinical benefit and the concern of dexamethasone neurotoxicity as demonstrated in animal studies, the practice of perineural dexamethasone administration needs to be further evaluated.