The minimally effective concentration of adrenaline in a low-concentration thoracic epidural analgesic infusion of bupivacaine, fentanyl and adrenaline after major surgery. A randomized, double-blind, dose-finding study

Extrapleural infusion of levobupivacaine versus levobupivacaine-sufentanil-adrenaline after video-assisted thoracoscopic surgery (VATS): A randomised controlled trial

BACKGROUND

Peripheral blocks are increasingly used for analgesia after video-assisted thoracic surgery (VATS). We hypothesised that addition of sufentanil and adrenaline to levobupivacaine would improve the analgesic effect of a continuous extrapleural block.

METHODS

We randomised 60 patients undergoing VATS to a 5-mL h-1 extrapleural infusion of levobupivacaine at 2.7 mg mL-1 (LB group) or levobupivacaine at 1.25 mg mL-1 , sufentanil at 0.5 μg mL-1 , and adrenaline at 2 μg mL-1 (LBSA group). The primary outcome was the cumulative morphine dose administered as patient-controlled analgesia (PCA-morphine) at 48 and 72 h. The secondary outcomes were pain according to numerical rating scale (NRS) at rest and after two deep breaths twice daily, peak expiratory flow (PEF) daily, quality of recovery (QoR)-15 score at 1 day and 3 weeks postoperatively, serum levobupivacaine concentrations at 1 h after the start and at the end of the intervention, and adverse events.

RESULTS

At 48 h, the median cumulative PCA-morphine dose for the LB group was 6 mg (IQR, 2-10 mg) and for the LBSA group 7 mg (IQR, 3-13.5 mg; p = .378). At 72 h, morphine doses were 10 mg (IQR, 3-22 mg) and 12.5 mg (IQR, 4-21 mg; p = .738), respectively. Median NRS score at rest and after two deep breaths was 3 or lower at all time points for both treatment groups. PEF did not differ between groups. Three weeks postoperatively, only the LB group returned to baseline QoR-15 score. The LB group had higher, but well below toxic, levobupivacaine concentrations at 48 and 72 h. The incidence of nausea, dizziness, pruritus and headache was equally low overall.

CONCLUSION

For a continuous extrapleural block, and compared to plain levobupivacaine at 13.5 mg h-1 , levobupivacaine at 6.25 mg h-1 with addition of sufentanil and adrenaline did not decrease postoperative morphine consumption. The levobupivacaine serum concentrations after 48 and 72 h of infusion were well below toxic levels, therefore our findings support the use of the maximally recommended dose of levobupivacaine for a 2- to 3-day continuous extrapleural block.

Maternal haemodynamics during labour epidural analgesia with and without adrenaline

OBJECTIVES

Labour is one of the most painful experiences in a woman's life. Epidural analgesia using low-concentration local anaesthetics and lipophilic opioids is the gold standard for pain relief during labour. Pregnancy in general, particularly labour, is associated with changes in maternal haemodynamic variables, such as cardiac output and heart rate, which increase and peak during uterine contractions. Adrenaline is added to labour epidural solutions to enhance efficacy by stimulating the α2-adrenoreceptor. The minimal effective concentration of adrenaline was found to be 2 μg mL^-1 for postoperative analgesia. The addition of adrenaline may also produce vasoconstriction, limiting the absorption of fentanyl into the systemic circulation, thereby reducing foetal exposure. However, adrenaline may influence the haemodynamic fluctuations, possibly adding to the strain on the circulatory system. The aim of this study was to compare the haemodynamic changes after application of labour epidural analgesia with or without adrenaline 2 μg mL^-1.

METHODS

This was a secondary analysis of a single-centre, randomised double-blind trial. Forty-one nulliparous women in labour requesting epidural analgesia were randomised to receive epidural solution of bupivacaine 1 mg mL^-1, fentanyl 2 μg mL^-1 with or without adrenaline 2 μg mL^-1. The participants were monitored using a Nexfin CC continuous non-invasive blood pressure and cardiac output monitor. The primary outcomes were changes in peak systolic blood pressure and cardiac output during uterine contraction within 30 min after epidural activation. The effect of adrenaline was tested statistically using a linear mixed-effects model of the outcome variables' dependency on time, adrenaline, and their interaction.

RESULTS

After excluding three patients due to poor data quality and two due to a malfunctioning epidural catheter, 36 patients (18 in each group) were analysed. The addition of adrenaline to the solution had no significant effect on the temporal changes in peak systolic blood pressure (p=0.26), peak cardiac output (0.84), or heart rate (p=0.91). Furthermore, no significant temporal changes in maternal haemodynamics (peak systolic blood pressure, p=0.54, peak cardiac output, p=0.59, or heart rate p=0.55) were associated with epidural analgesia during 30 min after epidural activation in both groups despite good analgesia.

CONCLUSIONS

The addition of 2 μg mL^-1 adrenaline to the epidural solution is not likely to change maternal haemodynamics during labour.

Effect of transcutaneous electrical nerve stimulation on quality of recovery and pain after abdominal hysterectomy

Background and Aims:

Transcutaneous electrical nerve stimulation (TENS) is a noninvasive complementary therapy for postoperative pain management. The effect of TENS on quality of recovery (QoR) and pain treatment in the early postoperative period is not well documented. The aim of this study was to evaluate the effect of TENS on postoperative QoR and pain in patients who had undergone a total abdominal hysterectomy with bilateral salpingo-oophorectomy (TAH + BSO).

Material and Methods:

Fifty-two patients were randomized into two groups: control (sham TENS treatment) and TENS (TENS treatment). QoR, dynamic pain, and static pain were evaluated after surgery.

Results:

The QoR score was significantly higher in the TENS group as compared with that in the control group (P = 0.029). Pain scores during coughing (dynamic pain) were significantly less in TENS group compared to control group (P <0.001). However, there was no between-group difference in pain scores at rest (static pain) or total analgesic consumption (P = 0.63 or P = 0.83, respectively).

Conclusion:

TENS may be a valuable tool to improve patients' QoR and dynamic pain scores after TAH + BSO.

A Randomized Controlled Trial Comparing Analgesic Efficacies of an Ultrasound-Guided Approach with and without a Combined Pressure Measurement Technique for Thoracic Paravertebral Blocks After Open Thoracotomy

Purpose

Ultrasound-guided thoracic paravertebral block (TPVB) is an established means for providing postoperative analgesia in thoracic surgery. However, there are conflicting results regarding the efficacy of post-thoracotomy pain management of ultrasound-guided TPVB when compared with that using traditional landmark approach. We therefore conducted a comparative study to evaluate the analgesic efficacy of TPVB when pressure measurement during needle advancement is combined with an ultrasound-guided approach.

Patients and Methods

The patients scheduled for lobectomy through thoracotomy were randomly allocated to receive either the ultrasound-guided approach only group (U group) or the ultrasound-guided approach combined with pressure measurement group (UP group) (n = 36 per group). Before thoracic muscle closure, 0.375% ropivacaine (20 mL) was administered as a bolus, followed by a continuous infusion of 0.2% ropivacaine (0.1 mL/kg/hr) in both groups. Postoperative pain was assessed using the visual analogue scale (VAS) pain score while resting and coughing. Local anesthetics and pethidine usage and sensory block area were also evaluated.

Results

The UP group showed significantly lower VAS scores, local anesthetics and pethidine usage, and a wider sensory block area than the U group.

Conclusion

A combined technique with ultrasound guidance and pressure measurement provided a superior analgesic effect over that of an ultrasound-guided approach alone for the management of post-thoracotomy pain.

Postoperative paralytic ileus after cytoreductive surgery combined with heated intraperitoneal chemotherapy

Background

Patients with peritoneal malignancy treated by cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC) are prone to develop postoperative paralytic ileus (POI). POI is associated with significant increase in both morbidity and mortality. CRS and HIPEC commonly result in prolonged POI (PPOI). The objective was to clarify the extent of PPOI in patients treated by CRS and HIPEC for peritoneal malignancy.

Methods

This was a prospective multicenter study including patients operated with CRS and HIPEC at the Department of Surgery, Aarhus University Hospital, Denmark and the Peritoneal Malignancy Institute, Basingstoke, United Kingdom. A total of 85 patients were included over 5 months. Patients prospectively reported parameters of postoperative gastrointestinal function in a diary from post-operative day 1 (POD1) until discharge. PPOI was defined as first defecation on POD6 or later.

Results

Median time to first flatus passage was 4 days (range 1–12). Median time to first defecation was 6 days (1–14). Median time to removal of nasojejunal tube was 4 days (3–13) and 7 days (1–43) for nasogastric tube. Forty-six patients (54%) developed PPOI. Patients with PPOI had longer time to first flatus (p<0.0001) and longer time to removal of nasojejunal tube (p=0.001). Duration of surgery correlated to time to first flatus (p=0.015) and time to removal of nasogastric or nasojejunal tube (p<0.0001) but not to time to first defecation (p=0.321).

Conclusions

Postoperative gastrointestinal paralysis remains a common and serious problem in patients treated with CRS and HIPEC.

Guidelines for Perioperative Care in Elective Colorectal Surgery: Enhanced Recovery After Surgery (ERAS®) Society Recommendations: 2018

BACKGROUND

This is the fourth updated Enhanced Recovery After Surgery (ERAS®) Society guideline presenting a consensus for optimal perioperative care in colorectal surgery and providing graded recommendations for each ERAS item within the ERAS® protocol.

METHODS

A wide database search on English literature publications was performed. Studies on each item within the protocol were selected with particular attention paid to meta-analyses, randomised controlled trials and large prospective cohorts and examined, reviewed and graded according to Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system.

RESULTS

All recommendations on ERAS® protocol items are based on best available evidence; good-quality trials; meta-analyses of good-quality trials; or large cohort studies. The level of evidence for the use of each item is presented accordingly.

CONCLUSIONS

The evidence base and recommendation for items within the multimodal perioperative care pathway are presented by the ERAS® Society in this comprehensive consensus review.

Enhanced Recovery After Surgery (ERAS®) in thoracic surgical oncology

Enhanced recovery after surgery (ERAS®) is a strategy that seeks to reduce patients’ perioperative stress response, thereby reducing potential complications, decreasing hospital length of stay and enabling patients to return more quickly to their baseline functional status. The concept was introduced in the late 1990s and was first adopted for use with patients undergoing open colorectal surgery. Since that time, the concept of ERAS has spread to multiple surgical specialties. This article explores the key elements for patient care using an ERAS protocol applied to minimally invasive thoracic surgery.

Essential Elements of Multimodal Analgesia in Enhanced Recovery After Surgery (ERAS) Guidelines

Perioperative multimodal analgesia uses combinations of analgesic medications that act on different sites and pathways in an additive or synergistic manner to achieve pain relief with minimal or no opiate consumption. Although all medications have side effects, opiates have particularly concerning, multisystemic, long-term, and short-term side effects, which increase morbidity and prolong admissions. Enhanced recovery is a systematic process addressing each aspect affecting recovery. This article outlines the evidence base forming the current multimodal analgesia recommendations made by the Enhanced Recovery After Surgery Society (ERAS). We describe current evidence and important future directions for effective perioperative multimodal analgesia in enhanced recovery pathways.

An Update on Drugs Used for Lumbosacral Epidural Anesthesia and Analgesia in Dogs

This review aims to report an update on drugs administered into the epidural space for anesthesia and analgesia in dogs, describing their potential advantages and disadvantages in the clinical setting. Databases searched include Pubmed, Google scholar, and CAB abstracts. Benefits of administering local anesthetics, opioids, and alpha₂ agonists into the epidural space include the use of lower doses of general anesthetics (anesthetic “sparing” effect), perioperative analgesia, and reduced side effects associated with systemic administration of drugs. However, the potential for cardiorespiratory compromise, neurotoxicity, and other adverse effects should be considered when using the epidural route of administration. When these variables are considered, the epidural technique is useful as a complementary method of anesthesia for preventive and postoperative analgesia and/or as part of a balanced anesthesia technique.

Adjuvant Agents in Regional Anesthesia in the Ambulatory Setting

PURPOSE OF REVIEW

A majority of surgical practice has involved ambulatory centers with the number of outpatient operations in the USA doubling to 26.8 million per year. Local anesthesia delivery provides numerous benefits, including increased satisfaction, earlier discharge, and reduction in unplanned hospital admission. Further, with the epidemic of opioid mediated overdoses, local anesthesia can be a key tool in providing an opportunity to reduce the need for other analgesics postoperatively.

RECENT FINDINGS

Adjuvants such as epinephrine and clonidine enhance local anesthetic clinical utility. Further, dexmedetomidine prolongs regional blockade duration effects. There has also been a significant interest recently in the use of dexamethasone. Studies have demonstrated a significant prolongation in motor and sensory block with perineural dexamethasone. Findings are conflicting as to whether intravenous dexamethasone has similar beneficial effects. However, considering the possible neurotoxicity effects, which perineural dexamethasone may present, it would be prudent not to consider intravenously administered dexamethasone to prolong regional block duration. Many studies have also demonstrated neurotoxicity from intrathecally administered midazolam. Therefore, midazolam as an adjuvant is not recommended. Magnesium prolongs regional block duration but related to paucity of studies as of yet, cannot be recommended. Tramadol yields inconsistent results and ketamine is associated with psychotomimetic adverse effects. Buprenorphine consistently increases regional block duration and reduce opioid requirements by a significant amount. Future studies are warranted to define best practice strategies for these adjuvant agents. The present review focuses on the many roles of local anesthetics in current ambulatory practice.

Pharmacogenomics and pharmacogenetics for the intensive care unit: a narrative review

PURPOSE

Knowledge of how alterations in pharmacogenomics and pharmacogenetics may affect drug therapy in the intensive care unit (ICU) has received little study. We review the clinically relevant application of pharmacogenetics and pharmacogenomics to drugs and conditions encountered in the ICU.

SOURCE

We selected relevant literature to illustrate the important concepts contained within.

PRINCIPAL FINDINGS

Two main approaches have been used to identify genetic abnormalities - the candidate gene approach and the genome-wide approach. Genetic variability in response to drugs may occur as a result of alterations of drug-metabolizing (cytochrome P [CYP]) enzymes, receptors, and transport proteins leading to enhancement or delay in the therapeutic response. Of relevance to the ICU, genetic variation in CYP-450 isoenzymes results in altered effects of midazolam, fentanyl, morphine, codeine, phenytoin, clopidogrel, warfarin, carvedilol, metoprolol, HMG-CoA reductase inhibitors, calcineurin inhibitors, non-steroidal anti-inflammatory agents, proton pump inhibitors, and ondansetron. Changes in cholinesterase enzyme function may affect the disposition of succinylcholine, benzylisoquinoline muscle relaxants, remifentanil, and hydralazine. Genetic variation in transport proteins leads to differences in the response to opioids and clopidogrel. Polymorphisms in drug receptors result in altered effects of β-blockers, catecholamines, antipsychotic agents, and opioids. Genetic variation also contributes to the diversity and incidence of diseases and conditions such as sepsis, malignant hyperthermia, drug-induced hypersensitivity reactions, cardiac channelopathies, thromboembolic disease, and congestive heart failure.

CONCLUSION

Application of pharmacogenetics and pharmacogenomics has seen improvements in drug therapy. Ongoing study and incorporation of these concepts into clinical decision making in the ICU has the potential to affect patient outcomes.

Enhanced Recovery After Surgery (ERAS) for gastrointestinal surgery, part 2: consensus statement for anaesthesia practice

Background

The present interdisciplinary consensus review proposes clinical considerations and recommendations for anaesthetic practice in patients undergoing gastrointestinal surgery with an Enhanced Recovery after Surgery (ERAS) programme.

Methods

Studies were selected with particular attention being paid to meta‐analyses, randomized controlled trials and large prospective cohort studies. For each item of the perioperative treatment pathway, available English‐language literature was examined and reviewed. The group reached a consensus recommendation after critical appraisal of the literature.

Results

This consensus statement demonstrates that anaesthesiologists control several preoperative, intraoperative and postoperative ERAS elements. Further research is needed to verify the strength of these recommendations.

Conclusions

Based on the evidence available for each element of perioperative care pathways, the Enhanced Recovery After Surgery (ERAS ^®) Society presents a comprehensive consensus review, clinical considerations and recommendations for anaesthesia care in patients undergoing gastrointestinal surgery within an ERAS programme. This unified protocol facilitates involvement of anaesthesiologists in the implementation of the ERAS programmes and allows for comparison between centres and it eventually might facilitate the design of multi‐institutional prospective and adequately powered randomized trials.

Anesthesia for colorectal surgery

Anesthesiologists play a pivotal role in facilitating recovery of patients undergoing colorectal surgery, as many Enhanced Recovery After Surgery (ERAS) elements are under their direct control. Successful implementation of ERAS programs requires that anesthesiologists become more involved in perioperative care and more aware of the impact of anesthetic techniques on surgical outcomes and recovery. Key to achieving success is strict adherence to the principle of aggregation of marginal gains. This article reviews anesthetic and analgesic care of patients undergoing elective colorectal surgery in the context of an ERAS program, and also discusses anesthesia considerations for emergency colorectal surgery.

Improving acute pain management in emergency medicine

Undertreatment of pain (oligoanalgesia) in the emergency department is common, and it negatively impacts patient care. Both failure of appropriate pain assessment and the potential for unsafe analgesic use contribute to the problem. As a result, achieving satisfactory analgesia while minimizing side effects remains particularly challenging for emergency physicians, both in the emergency department and after a patient is discharged. Improvements in rapid pain assessment and in evaluation of noncommunicative populations may result in a better estimation of which patients require analgesia and how much pain is present. New formulations of available treatments, such as rapidly absorbed, topical, or intranasal nonsteroidal anti-inflammatory drug formulations or intranasal opioids, may provide effective analgesia with an improved risk-benefit profile. Other pharmacological therapies have been shown to be effective for certain pain modalities, such as the use of antidepressants for musculoskeletal pain, γ-aminobutyric acid agonists for neuropathic and postsurgical pain, antipsychotics for headache, and topical capsaicin for neuropathic pain. Nonpharmacological methods of pain control include the use of electrical stimulation, relaxation therapies, psychosocial/manipulative therapies, and acupuncture. Tailoring of available treatment options to specific pain modalities, as well as improvements in pain assessment, treatment options, and formulations, may improve pain control in the emergency department setting and beyond.

The stability of a sulphite-free epidural analgesic solution containing fentanyl, bupivacaine, and adrenaline

BACKGROUND

Thoracic epidural infusion analgesia is optimised by using a triple component infusion containing a local anaesthetic, an opioid, and adrenaline. Adrenaline in solution is prone to oxidation, and stabilisers, such as antioxidants (e.g. sulphites) or chelators (edetates), are therefore commonly added. Sulphites may, however, have unwanted effects, especially allergic reactions. The aim of this study was to evaluate the stability of an analgesic infusion solution for epidural administration free of sulphites, containing adrenaline, fentanyl, bupivacaine, and disodium edetate.

METHODS

An epidural infusion solution containing adrenaline 2 μg/ml, fentanyl 2 μg/ml, bupivacaine 1 mg/ml, and disodium edetate 0.18 μg/ml was stored at 2-8°C for 4.5 months. A concentrate 11 times more potent, used for the production of the ready-to-use solution, was stored at 2-8°C for 9 months. Concentrations of the active ingredients were determined, pH was measured throughout the period, the clarity of the solutions was investigated, and the weight of the infusion bags recorded.

RESULTS

After 4.5 months at 2-8°C, the infusion solution contained adrenaline 97.5%, bupivacaine 100.9%, and fentanyl 102.6%. The pH stayed between 4.76 and 4.79, the solutions remained clear, and the weight was 99.9% of that found initially. The solution was also stable for 7 days at room temperature. The concentrate was stable (> 90%) for 9 months at 2-8°C.

CONCLUSION

The solution containing adrenaline, fentanyl, and bupivacaine, stabilised with disodium edetate, is stable for several months at 2-8°C, and at least for 7 days at room temperature without the addition of sulphites.

Epidural vs. intravenous fentanyl during colorectal surgery using a double-blind, double-dummy design

BACKGROUND

The overall therapeutic effectiveness of epidural fentanyl vs. the intravenous route is controversial. The present work describes a randomized, controlled, double-blind, double-dummy study of the intraoperative requirements of fentanyl administered by the intravenous or epidural routes during open colon surgery.

METHODS

Thirty patients were randomized to receive intraoperative analgesia with boluses of fentanyl administered by either the epidural or intravenous route (2 μg/kg). The first fentanyl bolus was administered 10 min before incision, and repeated boluses were given when mean arterial pressure or heart rate increased more than 20% over basal values. General anaesthesia was maintained with a propofol infusion. Intraoperative fentanyl and propofol requirements, time to awakening, time to analgesia request, and incidence of adverse effects were recorded.

RESULTS

Median [interquartile range (range)] fentanyl requirements in the epidural and intravenous groups were 0.81 [0.65 (0.47-2.61)] and 2.5 [1.08 (1.07-4.85)] μg/kg/h, respectively (P < 0.001). The epidural group had a shorter time to awakening, with a median of 8 min [4.5 (3-18)] compared with 20 min [12.5 (7-34)] for the intravenous group (P < 0.001). There were no significant differences in propofol requirements. The time to analgesia request was also delayed in the epidural group, with a median of 5 h [5.5 (1-16)] vs. 2 h [1 (1-5)] when fentanyl was administered intravenously (P < 0.001). The incidence of adverse effects was similar in both groups.

CONCLUSION

During major abdominal surgery, epidural administration requires lower doses of intraoperative fentanyl when compared with the intravenous route. Epidural fentanyl also facilitates early awakening and residual analgesia without increasing adverse events.

[Post-operative pain management in hospitals]

BACKGROUND

Relief of post-operative pain has a bearing on the patient's well-being, mobilisation and time confined to bed. The article discusses indications, contraindications and the efficacy of the various treatment modalities.

MATERIAL AND METHOD

We have examined review articles, meta-analyses and randomised controlled trials, identified through literature searches in PubMed.

RESULTS

The use of several medicines and techniques (multimodal pain treatment) is necessary to achieve a good balance between pain relief, side effects and risk. Systemic administration of paracetamol, NSAIDs, opioids and glucocorticoids is effective for post-operative pain. The same applies to epidural analgesia, peripheral nerve blocks and local anaesthetic wound infiltration. Subanaesthetic doses of ketamine have an opioid-sparing effect, but the optimal dosing regimen is uncertain. Gabapentinoids have an effect on post-operative pain, but the effect appears to vary depending on the type of operation and analgesic regimen. The effect of one analgesic will depend on which other drugs are used in multimodal pain treatment. Epidural analgesia, peripheral nerve blocks or extensive local infiltration analgesia is often necessary to relieve movement-related pain.

INTERPRETATION

Many treatment modalities are effective for post-operative pain. It is crucial that the treatment is well organised and that it includes routines for systematic pain assessment, efficacy and side effects of the pain management.

Pharmacological strategies to reduce pruritus during postoperative epidural analgesia after lumbar fusion surgery - a prospective randomized trial in 150 patients

Background

Epidural analgesia with bupivacain, epinephrine and fentanyl provides excellent pain control after lumbar fusion surgery, but pruritus and motor block are frequent side effects. Theoretically epidural ropivacain combined with oral oxycodone could decrease the incidence of these side effects. The two regimens were compared in a prospective randomized trial.

Patients and methods

150 patients (87 women) treated with posterior instrumented lumbar fusion were included. The mean age was 51 +/- 11 years. 76 were randomized to bupivacain, epinephrine and fentanyl (group B) and 74 to ropivacain and oxycodone (group R). Pruritus, motor block and pain were measured 6 hours after surgery, thereafter 6 times per day for 5 days. Any pain breakthrough episode was registered whenever it occurred.

Results

The epidural treatment could be performed in 143 patients (72 in group B and 71 in group R). Disturbing pruritus occurred in 53 patients in group B compared to 12 in group R (p < 0.0001). Motor blockade was most frequent on day 1, occurring in 45% of the patients with no difference between the groups. Both regimes gave good pain control with average VAS under 40, but the pain relief was statistically better in group B. The number of pain breakthrough episodes did not differ between the groups.

Conclusions

Pruritus could be reduced with a combination of epidural ropivacain and oral oxycodone, at the price of a slightly higher pain level. Ropivacaine was not found to be superior to bupivacaine with regard to motor blocks.

Pharmacogenomic considerations in the opioid management of pain

Physicians continue to struggle with the clinical management of pain, in part because of the large interindividual variability in the efficacy, occurrence of side effects and undesired severe adverse drug reactions from the prescribed analgesics. Pharmacogenomics, the study of how an individual's genetic inheritance affects the body's response to medications, has an important role and can explain some of this interindividual variability. Genetic identification of known variant alleles that affect the pharmacokinetics or pharmacodynamics of medications used for pain management can enable physicians to select the appropriate analgesic drug and dosing regimen for an individual patient, instead of empirical selection and dosing escalation. In this article, clinically relevant pharmacogenomic targets for the management of opioid pain, including efflux transporters, proteins that metabolize drugs, enzymes that regulate the neurotransmitters that modulate pain, and opioid receptors, will be reviewed.

A systematic review of comparative studies indicates that paravertebral block is neither superior nor safer than epidural analgesia for pain after thoracotomy

Background

The “gold standard” for pain relief after thoracotomy has been thoracic epidural analgesia (TEA). The studies comparing TEA with paravertebral block (PVB) and recent reviews recommend PVB as a novel, safer method than TEA.

Methods

A systematic search of the Cochrane and PubMed databases for prospective, randomized trials (RCTs) comparing TEA and PVB for post-thoracotomy analgesia was done. We assessed how TEA and PVB were performed, methods of randomization, assessment of pain relief, and complications. Abstracts only were excluded.

Results

Ten studies were included, comprising 224 patients randomized to TEA, 243 to PVB. The studies were heterogeneous. Therefore, a systematic narrative review with our evaluations is presented.

Only 3/10 trials reported the method of randomization. Pain during coughing was reported in only 5/10, pain assessment not specified in 5/10. Only 1/10 trials found PVB superior to TEA, but placed TEA catheters too low (<T7). TEA was superior to PVB in 1/10, during first 1.5 days. PVB and TEA were equally effective in 8/10. 5/10 trials found PVB had less hypotension or urinary retention. None of the studies used appropriate and optimal TEA: TEA was started after end of surgery in half, catheters placed too low (2/10), too high (1/10), not reported in (1/10). 7/10 infused local anaesthetic only, 2/10 added fentanyl, 1/10 added morphine, and none added adrenaline. PVB infusions had higher concentration of bupivacaine (5 mg/ml) in 2/10, 1/10 added fentanyl, 1/10 added ornipressin. Loading doses were higher in 5/10, and with more concentrated solutions in 5/10 of PVB than in the TEA group.

Conclusions

10 heterogeneous, mostly small, studies comparing TEA and PVB for post-thoracotomy analgesia do not allow conclusions on which method has superior analgesic efficacy and safety. The main methodological problem was that none of the studies use optimal thoracic epidural analgesia, with siting of catheters inappropriate in some and the epidural infusion containing too concentrated local anaesthetic because opioid and adrenaline were not added. Anatomical considerations (the paravertebral space comprises parts of the epidural space and contains spinal cord arteries) and personally experienced complications with PVB (paraplegia) convince us that PVB must have higher risk of, infrequent but serious, spinal cord complications than TEA. Percutaneous PVB may puncture pleura and lung.

Some surgeons expressed satisfaction with PVB because the method omits costly acute pain services for monitoring on surgical wards and saves time in the operating room. They are, however, bound to experience serious complications from PVB, sooner or later.

To our knowledge, optimally conducted epidural analgesia has not been compared with PVB. Current literature and our experience with both techniques for up to four decades, indicate that PVB may be an alternative for post-thoracotomy pain when TEA is infeasible for various patient-related reasons (Breivik et al., 2009). Severely disturbed haemostasis is a contraindication for PVB and TEA. Higher concentrations of local anaesthetics are needed to obtain intercostal nerve blocks and epidural analgesia with PVB, risking local anaesthetic intoxication. Robust monitoring regimen for effects and adverse effects is as important for PVB as for TEA.

Neurological impairment following myocardial ischemia associated with postoperative epidural analgesia

Although epidural analgesia reduces the postoperative stress response and provides good pain relief for patients, potential complications associated with the technique may decrease its acceptability for some patients. We describe a 76-year-old female who underwent surgery for carcinoma of the urinary tract. Postoperative epidural analgesia was performed at the postanesthesia care unit. Neither a repeat attempt nor accidental dural puncture was encountered during the procedure. Unfortunately, she sustained neurological impairment of the bilateral lower limbs following an episode of myocardial ischemia during the early postoperative period. When the neurological deficit was recognized following epidural anesthesia, poor puncture technique was the first to be blamed. In fact, a high level of sensory blockade could markedly decrease blood pressure and heart rate, particularly in the presence of hypovolemia, which might lead to impairment of coronary perfusion and result in myocardial ischemia. Severe systemic hypotension might further lead to hypoperfusion of the spinal cord, most possibly in the mid-thoracic region (T4 to T8) due largely to its relative hypovascularity. Therefore, we recommend that maintaining sufficient circulatory volume of the patient, evaluating and recording the neurological function of the patient and determining the possible risk factors associated with coronary arterial disease are imperative prior to performing an epidural procedure.

A systematic review of randomized trials evaluating regional techniques for postthoracotomy analgesia

BACKGROUND

Thoracotomy induces severe postoperative pain and impairment of pulmonary function, and therefore regional analgesia has been intensively studied in this procedure. Thoracic epidural analgesia is commonly considered the "gold standard" in this setting; however, evaluation of the evidence is needed to assess the comparative benefits of alternative techniques, guide clinical practice and identify areas requiring further research.

METHODS

In this systematic review of randomized trials we evaluated thoracic epidural, paravertebral, intrathecal, intercostal, and interpleural analgesic techniques, compared to each other and to systemic opioid analgesia, in adult thoracotomy. Postoperative pain, analgesic use, and complications were analyzed.

RESULTS

Continuous paravertebral block was as effective as thoracic epidural analgesia with local anesthetic (LA) but was associated with a reduced incidence of hypotension. Paravertebral block reduced the incidence of pulmonary complications compared with systemic analgesia, whereas thoracic epidural analgesia did not. Thoracic epidural analgesia was superior to intrathecal and intercostal techniques, although these were superior to systemic analgesia; interpleural analgesia was inadequate.

CONCLUSIONS

Either thoracic epidural analgesia with LA plus opioid or continuous paravertebral block with LA can be recommended. Where these techniques are not possible, or are contraindicated, intrathecal opioid or intercostal nerve block are recommended despite insufficient duration of analgesia, which requires the use of supplementary systemic analgesia. Quantitative meta-analyses were limited by heterogeneity in study design, and subject numbers were small. Further well designed studies are required to investigate the optimum components of the epidural solution and to rigorously evaluate the risks/benefits of continuous infusion paravertebral and intercostal techniques compared with thoracic epidural analgesia.

Perioperative spinal cord infarction in nonaortic surgery: report of three cases and review of the literature

Paraplegia caused by a spinal cord infarction (SCI) is a devastating perioperative complication, most often associated with aortic and spine surgery. We present two other clinical scenarios in which perioperative SCI may occur. They happened during surgical procedures performed with epidural anesthesia, in the presence of several specific risk factors such as spinal stenosis, vascular disease, intraoperative hypotension, or the use of epinephrine in the local anesthetic solution. Second, SCI may occur during episodes of postoperative hypotension in patients with a history of aortic aneurysms.

Assessment of pain

Valid and reliable assessment of pain is essential for both clinical trials and effective pain management. The nature of pain makes objective measurement impossible. Acute pain can be reliably assessed, both at rest (important for comfort) and during movement (important for function and risk of postoperative complications), with one-dimensional tools such as numeric rating scales or visual analogue scales. Both these are more powerful in detecting changes in pain intensity than a verbal categorical rating scale. In acute pain trials, assessment of baseline pain must ensure sufficient pain intensity for the trial to detect meaningful treatment effects. Chronic pain assessment and its impact on physical, emotional, and social functions require multidimensional qualitative tools and health-related quality of life instruments. Several disease- and patient-specific functional scales are useful, such as the Western Ontario and MacMaster Universities for osteoarthritis, and several neuropathic pain screening tools. The Initiative on

METHODS

Measurement, and Pain Assessment in Clinical Trials recommendations for outcome measurements of chronic pain trials are also useful for routine assessment. Cancer pain assessment is complicated by a number of other bodily and mental symptoms such as fatigue and depression, all affecting quality of life. It is noteworthy that quality of life reported by chronic pain patients can be as much affected as that of terminal cancer patients. Any assessment of pain must take into account other factors, such as cognitive impairment or dementia, and assessment tools validated in the specific patient groups being studied.

The addition of adrenaline to thoracic epidural meperidine does not improve analgesia following thoracotomy

PURPOSE

Patient-controlled epidural analgesia (PCEA) with meperidine provides effective analgesia following thoracotomy. Accumulation of normeperidine, a meperidine metabolite with neuroexcitatory effects, has led to recommendations to limit the use of meperidine postoperatively. The purpose of this study was to determine if the addition of adrenaline to PCEA meperidine decreased meperidine consumption, reduced serum normeperidine levels, and improved analgesia following thoracotomy.

METHODS

Following Research Ethics approval consenting patients were randomly assigned to PCEA with either meperidine (2 mgxmL(-1)) + adrenaline (2 microgxmL(-1)) or meperidine alone (2 mgxmL(-1)). All patients received a standardized anesthetic and similar perioperative care. Visual analogue pain scores (at rest and with activity), quality of recovery (QoR) scores, and side effects were documented six, 24, and 48 hr postoperatively. Serum levels of meperidine and normeperidine were measured at the same time points.

RESULTS

Forty-six patients completed the study protocol. Meperidine consumption (mean+/-SD) was similar in the meperidine + adrenaline and the meperidine groups (601+/-211 mg vs 580+/-211 mg over 48 hr, respectively; P=0.744). Serum meperidine levels were similar at all study time points. Serum normeperidine was not detected in any sample. Pain scores, QoR scores, and adverse events were comparable in both study groups.

CONCLUSION

The addition of adrenaline did not influence PCEA meperidine consumption, analgesia outcomes, or QoR. Normeperidine did not accumulate in patients of either study group during the 48-hr study period. Meperidine for patient controlled epidural analgesia, with or without adrenaline, provides effective post-thoracotomy analgesia in selected patients.

An isobolographic analysis of diamorphine and levobupivacaine for epidural analgesia in early labour

BACKGROUND

Few data describe the pharmacological interactions between local anaesthetics and opioids. The aim of this study was to measure the median effective concentration (MEC) of diamorphine and levobupivacaine when given separately and as mixtures for epidural analgesia, and determine whether the combination is additive or synergistic.

METHODS

One hundred and twenty patients were enrolled in this prospective randomized, two-phase, double-blind study. In the first phase, 60 women were randomized to receive a fixed 20 ml volume of either levobupivacaine or diamorphine epidurally . Dosing was determined using up-down sequential allocation with testing intervals, respectively, of 0.01%w/v and 12.5 microg ml(-1). After estimations of the MEC of levobupivacaine and diamorphine, a further 60 patients were randomized in the second phase to one of the three mixtures: (a) diamorphine 70 microg ml(-1) (fixed) and levobupivacaine (testing interval 0.004%w/v, starting at 0.044%w/v); (b) levobupivacaine 0.044%w/v (fixed) and diamorphine (testing interval 7 microg ml(-1), starting at 70 microg ml(-1)); and (c) bivariate diamorphine and levobupivacaine (testing intervals of 7 microg ml(-1) and 0.004%w/v starting at 70 microg ml(-1) and 0.044% w/v respectively).

RESULTS

The MEC estimates from the first phase were 143.8 microg ml(-1) (95% CI 122.2-165.3) for diamorphine and 0.083%w/v (95% CI 0.071-0.095) for levobupivacaine. In the second phase, the MEC and interaction index (gamma) of the three combinations were: diamorphine 65.5 microg ml(-1) (56.8-74.2), gamma = 0.99; levobupivacaine 0.041%w/v (0.037-0.049), gamma = 0.98; and for the fixed combination diamorphine 69.5 microg ml(-1) (60.5-78.5) and levobupivacaine 0.044%w/v (0.039-0.049), gamma = 1.02.

CONCLUSION

The combination of diamorphine and levobupivacaine is additive and not synergistic when used for epidural analgesia in the first stage of labour.

Neuraxial drug administration: a review of treatment options for anaesthesia and analgesia

Neuraxial drug administration describes techniques that deliver drugs in close proximity to the spinal cord, i.e. intrathecally into the CSF or epidurally into the fatty tissues surrounding the dura, by injection or infusion. This approach was initially developed in the form of spinal anaesthesia over 100 years ago. Since then, neuraxial drug administration has evolved and now includes a wide range of techniques to administer a large number of different drugs to provide anaesthesia, but also analgesia and treatment of spasticity in a variety of acute and chronic settings. This review concentrates on the pharmacological agents used and the clinical basis behind currently utilised approaches to neuraxial drug administration. With regard to local anaesthetics, the main focus is on the development of the enantiomer-specific compounds ropivacaine and levobupivacaine, which provide similar efficacy to bupivacaine with a reduced risk of severe cardiotoxicity. Opioids are the other group of drugs widely used neuraxially, in particular to provide analgesia alone or more commonly in combination with other agents. The physicochemical properties of the various opioids explain the main differences in efficacy and safety between these drugs when used intrathecally, of which morphine, fentanyl and sufentanil are most commonly used. Another group of drugs including clonidine, dexmedetomidine and epinephrine (adrenaline) provide neuraxial analgesia via alpha-adrenergic receptors and are used mainly as adjuvants to local anaesthetics and opioids. Furthermore, intrathecal baclofen is in routine clinical use to treat spasticity in a number of neurological conditions. Beside these established approaches, a wide range of other drugs have been assessed for neuraxial administration to provide analgesia; however, most are in various early stages of investigation and are not used routinely. These drugs include neostigmine, ketamine, midazolam and adenosine, and the conotoxin ziconotide. The latter is possibly the most unusual compound here; it has recently gained registration for intrathecal use in specific chronic pain conditions.

Levobupivacaine-Sufentanil With or Without Epinephrine During Epidural Labor Analgesia

In a prospective, randomized, double-blind study, we investigated whether epinephrine increased the efficacy of levobupivacaine and sufentanil during epidural labor analgesia. Seventy term parturients received an epidural injection of levobupivacaine 0.125% and sufentanil 0.75 microg/mL with or without 1:800,000 epinephrine. After an initial dose of 10 mL, a patient-controlled analgesia pump was started. Total and hourly drug consumption, pain scores using the visual analog scale, sensory and motor block, duration of labor, vital variables, maternal and neonatal outcome, and side effects were compared. If the parturients experienced insufficient pain relief during the study, even after a rescue dose of 10 mL, they were excluded from further study and received 10 mL of bupivacaine 0.125% and sufentanil 0.75 microg/mL with 1:800,000 epinephrine. Hourly drug consumption, rescue dosing, and pain scores at 15 min and 20 min were lower in the epinephrine group. The incidence of motor block and duration of the second stage of labor tended to be higher in the epinephrine group and were associated with lower Apgar scores at 1 and 5 min. These findings suggest that the addition of epinephrine intensifies the effects of epidural levobupivacaine and sufentanil but may cause more motor block.

Pharmacogenetics and anesthesiologists

Genetic variation contributes to an individual’s sensitivity and response to a variety of drugs important to anesthetic practice. Early insights into the clinical impact of pharmacogenetics were provided by anesthesiology – investigations into prolonged apnea after succinylcholine administration, thiopental-induced porphyria and malignant hyperthermia contributed to the novel science of pharmacogenetics in the early 1960s. Genetic polymorphisms involved in pharmacokinetics (absorption, distribution, metabolism, and excretion of drugs) and pharmacodynamics (receptors, ion channels and enzymes) can affect an individual’s response to the drugs used in anesthetic practice. In addition, genetic variation in proteins directly unrelated to drug action or metabolism can influence responses to environmental changes that occur during anesthesia. This review will summarize the current knowledge of genetic variation in response to drugs relevant to anesthesia, and how this impacts upon clinical practice.

Best practice recommendations for anesthetic perioperative care and pain management in weight loss surgery

OBJECTIVE

To develop evidence-based recommendations that optimize the safety and efficacy of perioperative anesthetic care and pain management in weight loss surgery (WLS) patients.

RESEARCH METHODS AND PROCEDURES

This Task Group examined the scientific literature on anesthetic perioperative care and pain management published in MEDLINE from January 1994 to March 2004. We also reviewed additional data from other sources (e.g., book chapters). The search yielded 195 abstracts, of which 35 references were reviewed in detail. Task Group consensus was used to provide recommendations when evidence in the literature was insufficient.

RESULTS

We developed anesthesia practice and patient safety advisory recommendations for preoperative evaluation, intraoperative management, and postoperative care and pain management of WLS patients. We also provided suggestions related to medical error reduction and systems improvements, credentialing, and future research.

DISCUSSION

Obesity-related comorbidities including obstructive sleep apnea place WLS patients at increased risk for complications perioperatively. Regarding perioperative safety and outcomes, conclusive evidence beyond the accepted standard of care in the reviewed literature is limited. Few reports specifically address the perioperative needs of severely obese patients. In this advisory, we synthesize current knowledge and make best practice recommendations for perioperative care and pain management in WLS patients. These recommendations require periodic review as further medical knowledge and evidence evolve.

Genetic variability and clinical efficacy of morphine

The individual variability of opioid pharmacology suggests that the patients' genetic disposition influences the response to opioids. Given the complexity of morphine pharmacology, variability may be caused by several genes. We review data which shows that variability in genes coding the enzyme metabolizing morphine (UGT2B7 gene), mu-opioid receptors (OPRM gene) and blood-brain barrier (BBB) transport of morphine by multidrug resistance transporters (MDR1 gene) influences the clinical efficacy of morphine. Furthermore, variability in an enzyme degrading catecholamines (COMT gene) alters the efficacy of morphine demonstrating that genetic variability in non-opioid systems may indirectly influence the clinical efficacy from morphine. Thus, results obtained so far strongly argue that opioid efficacy is partly related to inborn properties caused by genetic variability.

Advantages and disadvantages of adrenaline in regional anaesthesia

Adrenaline has been added to local anaesthetic solutions for more than a century. The aim has been to delay the absorption of the local anaesthetic drug and to prolong and enhance its anaesthetic effect, both in peripheral and central neuraxial blockades. The intention in this chapter has been to give up-to-date knowledge about adrenaline as an adjuvant to local anaesthetics and/or opioids in clinical peripheral and central blockades. My own research has focused on optimizing postoperative epidural analgesia by adding adrenaline and/or fentanyl to an epidural mixture with dilute bupivacaine or ropivacaine. The main part of this chapter will therefore focus on the advantages and disadvantages of adrenaline in epidural analgesia. However, recent knowledge about adrenaline in peripheral blockade will also be covered, together with some pharmaceutical comments on the shelf-life of local anaesthetic mixtures containing adrenaline.

Enhanced recovery after surgery: a consensus review of clinical care for patients undergoing colonic resection

BACKGROUND & AIMS

Clinical care of patients undergoing colonic surgery differs between hospitals and countries. In addition, there is considerable variation in rates of recovery and length of hospital stay following major abdominal surgery. There is a need to develop a consensus on key elements of perioperative care for inclusion in enhanced recovery programmes so that these can be widely adopted and refined further in future clinical trials.

METHODS

Medline database was searched for all clinical studies/trials relating to enhanced recovery after colorectal resection. Relevant papers from the reference lists of these articles and from the authors' personal collections were also reviewed. A combination of evidence-based and consensus methodology was used to develop the resulting enhanced recovery after surgery (ERAS) clinical care protocol.

RESULTS AND CONCLUSIONS

Within traditional perioperative practice there is considerable evidence supporting a range of manoeuvres which, in isolation, may improve individual aspects of recovery after colonic surgery. The present manuscript reviews these issues in detail. There is also growing evidence that an integrated multimodal approach to perioperative care can result in an overall enhancement of recovery. However, effects on major morbidity and mortality remain to be determined. A protocol is presented which is in current use by the ERAS Group and may provide a standard of care against which either current or future novel elements of an enhanced recovery approach can be tested for their effect on outcome.

Impact of Acute Pain and Its Management for Thoracic Surgical Patients

Perioperative analgesia for thoracotomy has evolved in concert with increasing knowledge of the impact of pain on recovery, the origin of this pain, and new methods for treating it. Thoracic surgery is one of the few areas where there is more general agreement between surgeons and anesthesiologists as to the importance of aggressive pain management, often with an indwelling epidural catheter left in place until after thoracostomy tube removal. The reasons for this agreement is that it has become increasingly clear to both specialties that pain puts patients with decreased pulmonary reserve who undergo thoracotomy at greater risk for morbidity. Future studies need to examine drugs or drug combinations that can lead to further reductions in the often intense pain that patients receiving aggressive epidural analgesia still experience. Studies directed at finding interventions capable of reducing the rate of long-term postthoracotomy pain still need to be performed.

Stability of an epidural analgesic admixture containing epinephrine, fentanyl and bupivacaine

The addition of epinephrine to solutions containing fentanyl and bupivacaine for epidural infusion has been shown to improve the quality of analgesia. However, this admixture is not available commercially in the United Kingdom. Moreover, stability data applicable to UK practice for this admixture are limited. This study investigated the stability of fentanyl 2 microg.ml(-1) plus bupivacaine 1 mg.ml(-1) in PVC bags with and without epinephrine 2 microg.ml(-1) over a period of 184 days both at room temperature and at 4 degrees C. All infusions were found to be stable over the study period (> 90% remaining) using stability-indicating High Performance Liquid Chromatography (HPLC) methods, with no changes in physical appearance or pH (range 4.5-4.2). The infusions were prepared using standard pharmaceutical products, so facilitating the batch preparation of epinephrine, fentanyl and bupivacaine epidural solutions by hospital pharmacy departments.