Median Effective Local Anesthetic Doses of Plain Bupivacaine and Ropivacaine for Spinal Anesthesia Administered Via a Spinal Catheter for Brachytherapy of the Lower Abdomen:

Effective Dose Range of Intrathecal Isobaric Bupivacaine to Achieve T5–T10 Sensory Block Heights for Elderly and Overweight Patients: An Observational Study

Background and Objectives: The dose selection for isobaric bupivacaine determines the success of spinal anesthesia (SA). A dose higher than the optimal dose causes high SA, whereas an underdose leads to inadequate spread of cephalad. As it involves anatomical and physiological alterations, the dosing should be reduced with advancing age and body mass index values. Therefore, this study aimed to demonstrate the association between the isobaric bupivacaine dose and block height, and to determine the dose intervals of bupivacaine to achieve the T5–T10 sensory block with a low probability of high SA in elderly and overweight patients. Material and Methods: This retrospective observational study recruited 1079 adult patients who underwent SA with 0.5% isobaric bupivacaine from 2018 to 2021. The patients were divided into four categories: category 1 (age < 60, BMI < 25), category 2 (age < 60, BMI ≥ 25), category 3 (age ≥ 60, BMI < 25), and category 4 (age ≥ 60, BMI ≥ 25). The bupivacaine dose and sensory block height (classified into three levels: high (T1–T4), favorable (T5–T10), and low (T11–L2)) were recorded. Results: The sensory block level increased significantly with increasing doses of bupivacaine for patients in categories 1 and 2. The suggested dose ranges for the favorable block heights were 15–17 and 10.5–16 mg in patient categories 1–2 and 3–4, respectively. In these dose ranges, the probability range of high SA was 10–15%. Conclusions: The sensory block height following SA was associated with the bupivacaine dose in patients aged <60 years. Regardless of the BMI, the suggested dose ranges of 0.5% isobaric bupivacaine are 15–17 mg (3.0–3.4 mL) and 10.5–16 mg (2.1–3.2 mL) for patients aged <60 and ≥60 years, respectively.

Opioid consumption and pain in patients with gynecological cancer who underwent spinal anesthesia vs. general anesthesia for interstitial brachytherapy

AIMS

Interstitial brachytherapy (ISBT) is an effective option for delivering conformal high dose radiation to the target volume with better organ-at risk sparing but is thought to be more invasive and painful than other methods. This study investigated pain levels and opioid consumption in patients who received spinal anesthesia (SA) or general anesthesia (GA) for their ISBT.

MATERIALS AND METHODS

Patients that underwent ISBT from April 2014 to September 2018 were analyzed from a prospective institutional database. The most prevalent malignancies were cervical (45%), recurrent endometrial (27%) and vaginal (20%) cancers. Baseline patient characteristics, radiation treatment details, anesthesia records, and inpatient charts were obtained. Opioid consumption was quantified as oral morphine equivalent per day (OMEq/day) from implantation until removal. Pain score levels were collected by using an 11-point scoring system.

RESULTS

Ninety nine patients received GA and 40 patients received SA as their anesthesia for ISBT. During their first admission, 76 patients (55%) required intravenous opioids. Patients receiving SA had significantly lower mean pain scores on the morning of their procedure 6 (Interquartile range [IQR] 2-8) vs. 0 (IQR: 0-1); p < 0.001]. Pain did not significantly differ between cohorts at any other time. During the first admission, SA patients had a lower median opioid usage of 23 (IQR: 9-47) mg/day compared to GA patients at 38 (IQR: 21-71) mg/day (p = 0.011). No difference in opioid consumption was seen during subsequent admissions.

CONCLUSIONS

In patients undergoing ISBT, SA provides better immediate pain control post insertion compared to GA. Patients who received SA used lower amounts of opioids during their first ISBT insertion.

Staged intraperitoneal brachytherapy and hyperthermic intraperitoneal chemotherapy in an adolescent: novel anesthetic challenges for pediatric anesthetists

Newer techniques that have found a place in cancer management in adults are offered far less commonly in pediatric patients. We present a case of a patient with recurrent Wilms' tumor managed with a novel combination of cytoreductive surgery, intraperitoneal brachytherapy, and subsequent hyperthermic intraperitoneal chemotherapy. Each stage presents challenges that the pediatric anesthetist is unlikely to have faced before. Such cases require flexibility and thorough planning to manage the combination of major surgery, remote anesthesia with brachytherapy and hyperthermic chemotherapy with its potential for metabolic derangement, significant fluid shifts, analgesic care, and potential exposure of staff to cytotoxic agents. Comprehensive care can be offered in pediatric centers.

Optimal effective concentration of ropivacaine for postoperative analgesia by single-shot femoral–sciatic nerve block in outpatient knee arthroscopy

Objective

To compare analgesic and mobility effects of different ropivacaine concentrations in femoral–sciatic nerve block, for postoperative analgesia in knee arthroscopy.

Methods

Outpatients (American Society of Anesthesiologists physical classification status of I or II), scheduled for elective knee arthroscopy, were randomly allocated to one of seven groups, prospectively investigating different concentrations of ropivacaine (0.12%; 0.14%; 0.16%; 0.18%; 0.20%; 0.22% or 0.50%), for ultrasound-guided femoral–sciatic nerve block procedures for postoperative analgesia. Visual analogue scale (VAS) pain scores and motor block evaluation scales were observed at 4, 8, 16 and 24 h postsurgery.

Results

In total, 105 patients were enrolled; results were analysed for 103. VAS scores for the 0.12%, 0.14% and 0.16% groups were significantly different from the 0.50% group. There were no significant differences between the 0.18%, 0.20%, 0.22% and 0.50% groups: half maximal effective concentrations and 95% maximal effective concentrations of ropivacaine were 0.158 (95% confidence intervals [CI] 0.149, 0.167) and 0.198 (95% CI 0.186, 0.221), respectively. Rates of motor blockade (Bromage score or hip motor function scale > 0) were significantly different between the 0.50% group and all other ropivacaine doses.

Conclusion

The 0.20% ropivacaine dose for femoral–sciatic nerve block in knee arthroscopy provided satisfactory postoperative analgesia, while preserving ability of motion.

Drug therapy for preventing post-dural puncture headache

BACKGROUND

Post-dural (post-lumbar or post-spinal) puncture headache (PDPH) is one of the most common complications of diagnostic, therapeutic or inadvertent lumbar punctures. Many drug options have been used to prevent headache in clinical practice and have also been tested in some clinical studies, but there are still some uncertainties about their clinical effectiveness.

OBJECTIVES

To assess the effectiveness and safety of drugs for preventing PDPH in adults and children.

SEARCH METHODS

The search strategy included the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library 2012, Issue 5), MEDLINE (from 1950 to May 2012), EMBASE (from 1980 to May 2012) and CINAHL (from 1982 to June 2012). There was no language restriction.

SELECTION CRITERIA

We considered randomised controlled trials (RCTs) that assessed the effectiveness of any drug used for preventing PDPH.

DATA COLLECTION AND ANALYSIS

Review authors independently selected studies, assessed risks of bias and extracted data. We estimated risk ratios (RR) for dichotomous data and mean differences (MD) for continuous outcomes. We calculated a 95% confidence interval (CI) for each RR and MD. We did not undertake meta-analysis because participants' characteristics or assessed doses of drugs were too different in the included studies. We performed an intention-to-treat (ITT) analysis.

MAIN RESULTS

We included 10 RCTs (1611 participants) in this review with a majority of women (72%), mostly parturients (women in labour) (913), after a lumbar puncture for regional anaesthesia. Drugs assessed were epidural and spinal morphine, spinal fentanyl, oral caffeine, rectal indomethacin, intravenous cosyntropin, intravenous aminophylline and intravenous dexamethasone.All the included RCTs reported data on the primary outcome, i.e. the number of participants affected by PDPH of any severity after a lumbar puncture. Epidural morphine and intravenous cosyntropin reduced the number of participants affected by PDPH of any severity after a lumbar puncture when compared to placebo. Also, intravenous aminophylline reduced the number of participants affected by PDPH of any severity after a lumbar puncture when compared to no intervention, while intravenous dexamethasone increased it. Spinal morphine increased the number of participants affected by pruritus when compared to placebo, and epidural morphine increased the number of participants affected by nausea and vomiting when compared to placebo. Oral caffeine increased the number of participants affected by insomnia when compared to placebo.The remainder of the interventions analysed did not show any relevant effect for any of the outcomes.None of the included RCTs reported the number of days that patients stayed in hospital.

AUTHORS' CONCLUSIONS

Morphine and cosyntropin have shown effectiveness for reducing the number of participants affected by PDPH of any severity after a lumbar puncture, when compared to placebo, especially in patients with high risk of PDPH, such as obstetric patients who have had an inadvertent dural puncture. Aminophylline also reduced the number of participants affected by PDPH of any severity after a lumbar puncture when compared to no intervention in patients undergoing elective caesarean section. Dexamethasone increased the risk of PDPH, after spinal anaesthesia for caesarean section, when compared to placebo. Morphine also increased the number of participants affected by adverse events (pruritus and nausea and vomiting)There is a lack of conclusive evidence for the other drugs assessed (fentanyl, caffeine, indomethacin and dexamethasone).These conclusions should be interpreted with caution, owing to the lack of information, to allow correct appraisal of risk of bias and the small sample sizes of studies.

Polyanalgesic Consensus Conference 2012: recommendations for the management of pain by intrathecal (intraspinal) drug delivery: report of an interdisciplinary expert panel

INTRODUCTION

The use of intrathecal (IT) infusion of analgesic medications to treat patients with chronic refractory pain has increased since its inception in the 1980s, and the need for clinical research in IT therapy is ongoing. The Polyanalgesic Consensus Conference (PACC) panel of experts convened in 2000, 2003, and 2007 to make recommendations on the rational use of IT analgesics based on preclinical and clinical literature and clinical experiences.

METHODS

The PACC panel convened again in 2011 to update the standard of care for IT therapies to reflect current knowledge gleaned from literature and clinical experience. A thorough literature search was performed, and information from this search was provided to panel members. Analysis of published literature was coupled with the clinical experience of panel members to form recommendations regarding the use of IT analgesics to treat chronic pain.

RESULTS

After a review of literature published from 2007 to 2011 and discussions of clinical experience, the panel created updated algorithms for the rational use of IT medications for the treatment of neuropathic pain and nociceptive pain.

CONCLUSIONS

The advent of new algorithmic tracks for neuropathic and nociceptive pain is an important step in improving patient care. The panel encourages continued research and development, including the development of new drugs, devices, and safety recommendations to improve the care of patients with chronic pain.

Repeated Intrathecal Administration of Ropivacaine Causes Neurotoxicity in Rats

Previous studies have shown that ropivacaine is the least neurotoxic local anaesthetic. Most of the data derive from short-term ropivacaine injection into the subarachnoid space. Intrathecal administration for a prolonged period, and the histological changes and behavioural effects of repeated intrathecal administration, have not previously been investigated. We studied the possible neurotoxicity of intrathecal injection of ropivacaine in a rat model.

Rats received 0.12 ml/kg body weight of ropivacaine at concentrations of 0.5 or 1%, or normal saline only, via an implanted intrathecal catheter at 90-minute intervals for 12 hours. On days 1, 3, 5, 7, 14 and 28, the spinal cord was examined by light and electron microscopy at the L3 level. We assessed sensory thresholds to noxious stimulation, behavioural change and protein kinase B immunoreactivity for possible neuronal injury within the spinal cord.

Ropivacaine 1% induced thermal hyperalgesia and mechanical allodynia, neuronal injury characterised by tissue oedema, proliferation of glial cells, neuronal morphology changes and degeneration and protein kinase B expression. There were no significant differences in motor function as a result of different concentrations of ropivacaine.

Repeated intrathecal injection of ropivacaine 1% can induce neurotoxicity in rats. Our data suggests that expression of protein kinase B might be involved in this neurotoxicity.

Comparison of intrathecal bupivacaine and ropivacaine with different doses of sufentanil

BACKGROUND

Spinal bupivacaine produces a complete anaesthetic block of a longer duration than ropivacaine, which leads to a potentially increased risk of failure. A combination of sufentanil to ropivacaine may improve the block's reliability.

METHODS

Sixty-four patients, scheduled for varicose vein stripping or the tension-free vaginal tape procedure, were allocated to receive double-blindly, spinal bupivacaine 10 mg (Group 1) or ropivacaine 10 mg without (Group 2) or with sufentanil 2.5 mcg (Group 3), 5 mcg (Group 4). Sensory block was tested with pinprick and motor block was evaluated with the Bromage scale until full recovery. The primary endpoint was to compare the duration of sensory block evaluated by regression to S2.

RESULTS

In comparison with bupivacaine, ropivacaine produced a shorter duration sensory block (median at 68, 90 and 120 min in groups 2, 3 and 4, respectively, vs. 150 min in Group 1) and motor block (median at 90, 98 and 120 min in groups 2, 3 and 4 vs. 180 min in Group 1). Motor blockade was significantly less important in patients receiving spinal ropivacaine (median values for the Bromage scale at 3 in groups 2, 3 and 4, vs. 1 in Group 1). Pruritus was significantly more frequent in patients receiving spinal sufentanil (Groups 3 and 4 vs. Groups 1 and 2).

CONCLUSION

Plain bupivacaine 10 mg has a longer recovery profile than the same dose of ropivacaine with or without sufentanil.

In vitro exposure of human fibroblasts to local anaesthetics impairs cell growth

Lidocaine, bupivacaine or ropivacaine are used routinely to manage perioperative pain. Sparse data exist evaluating the effects of local anaesthetics (LA) on fibroblasts, which are involved actively in wound healing. Therefore, we investigated the effects of the three LA to assess the survival, viability and proliferation rate of fibroblasts. Human fibroblasts were exposed to 0·3 mg/ml and 0·6 mg/ml of each LA for 2 days, followed by incubation with normal medium for another 1, 4 or 7 days (group 1). Alternatively, cells were incubated permanently with LA for 3, 6 or 9 days (group 2). Live cell count was assessed using trypan blue staining. Viability was measured by the tetrazolium bromide assay. Proliferation tests were performed with the help of the colorimetric bromodeoxyuridine assay. Production of reactive oxygen species (ROS) was determined, measuring the oxidation of non-fluorescent-2,7'-dichlorofluorescin. Treatment of cells with the three LA showed a concentration-dependent decrease of live cells, mitochondrial activity and proliferation rate. Group arrangement played a significant role for cell count and proliferation, while exposure time influenced viability. Among the analysed LA, bupivacaine showed the most severe cytotoxic effects. Increased production of ROS correlated with decreased viability of fibroblasts in lidocaine- and bupivacaine-exposed cells, but not upon stimulation with ropivacaine. This study shows a concentration-dependent cytotoxic effect of lidocaine, bupivacaine and ropivacaine on fibroblasts in vitro, with more pronounced effects after continuous incubation. A possible mechanism of cell impairment could be triggered by production of ROS upon stimulation with lidocaine and bupivacaine.

The median effective dose of bupivacaine, levobupivacaine, and ropivacaine after intrathecal injection in lower limb surgery

BACKGROUND

Intrathecal anesthesia is commonly used for lower limb surgery. Bupivacaine, levobupivacaine, and ropivacaine have all been used as intrathecal drugs, but their relative potency in this context has not been fully determined. In this study, we determined the median effective dose (ED(50)) of these three local anesthetics for intrathecal anesthesia in lower limb surgery and hence their relative potencies.

METHODS

Seventy-five patients scheduled for lower limb surgery under combined spinal-epidural anesthesia were randomly allocated to one of three groups receiving intrathecal bupivacaine, levobupivacaine, or ropivacaine. The dose of local anesthetic was varied using up-down sequential allocation technique. The dose for the first patient in each group was 8 mg, and the dosing increment was set at 1 mg. Subsequent doses in each group were determined by the outcome in the previous patient using success or failure of the spinal anesthesia as the primary end point. A success was recorded if a bilateral T12 sensory block to cold was attained within 20 min after intrathecal injection, and the surgery proceeded successfully until at least 50 min after the intrathecal injection without supplementary epidural injection. The ED(50) was calculated using the method of Dixon and Massey.

RESULTS

The ED(50)s were 5.50 mg for bupivacaine (95% confidence interval [CI]: 4.90-6.10 mg), 5.68 mg for levobupivacaine (95% CI: 4.92-6.44 mg), and 8.41 mg for ropivacaine (95% CI: 7.15-9.67 mg) in intrathecal anesthesia. The relative anesthetic potency ratios are 0.97 (95% CI: 0.81-1.17) for levobupivacaine/bupivacaine, 0.65 (95% CI: 0.54-0.80) for ropivacaine/bupivacaine, and 0.68 (95% CI: 0.55-0.84) for ropivacaine/levobupivacaine.

CONCLUSION

This study suggests that in intrathecal anesthesia for lower limb surgery, ropivacaine is less potent than levobupivacaine and bupivacaine, whereas the potency is similar between levobupivacaine and bupivacaine.