PROcedure-SPECific postoperative pain management guideline for laparoscopic colorectal surgery: A systematic review with recommendations for postoperative pain management.

Colorectal cancer is the second most common cancer diagnosed in women and third most common in men. Laparoscopic resection has become the standard surgical technique worldwide given its notable benefits, mainly the shorter length of stay and less postoperative pain. The aim of this systematic review was to evaluate the current literature on postoperative pain management following laparoscopic colorectal surgery and update previous procedure-specific pain management recommendations. The primary outcomes were postoperative pain scores and opioid requirements. We also considered study quality, clinical relevance of trial design, and a comprehensive risk-benefit assessment of the analgesic intervention. We performed a literature search to identify randomised controlled studies (RCTs) published before January 2022. Seventy-two studies were included in the present analysis. Through the established PROSPECT process, we recommend basic analgesia (paracetamol for rectal surgery, and paracetamol with either a nonsteroidal anti-inflammatory drug or cyclo-oxygenase-2-specific inhibitor for colonic surgery) and wound infiltration as first-line interventions. No consensus could be achieved either for the use of intrathecal morphine or intravenous lidocaine; no recommendation can be made for these interventions. However, intravenous lidocaine may be considered when basic analgesia cannot be provided.

Chronic post amputation pain: pathophysiology and prevention options for a heterogenous phenomenon.

PURPOSE OF REVIEW: Chronic postamputation pain (cPAP) remains a clinical challenge, and current understanding places a high emphasis on prevention strategies. Unfortunately, there is still no evidence-based regimen to reliably prevent chronic pain after amputation. RECENT FINDINGS: Risk factors for the development of phantom limb pain have been proposed. Analgesic preventive interventions are numerous and no silver bullet has been found. Novel techniques such as neuromodulation and cryoablation have been proposed. Surgical techniques focusing on reimplantation of the injured nerve might reduce the incidence of phantom limb pain after surgery. SUMMARY: Phantom limb pain is a multifactorial process involving profound functional and structural changes in the peripheral and central nervous system. These changes interact with individual medical, psychosocial and genetic patient risk factors. The patient collective of amputees is very heterogeneous. Available evidence suggests that efforts should focus on prevention of phantom limb pain, since treatment is notoriously difficult. Questions as yet unanswered include the evidence-base of specific analgesic interventions, their optimal "window of opportunity" where they may be most effective, and whether patient stratification according to biopsychosocial risk factors can help guide preventive therapy.

Procedure-specific acute pain trajectory after elective total hip arthroplasty: systematic review and data synthesis.

BACKGROUND: For most procedures, there is insufficient evidence to guide clinicians in the optimal timing of advanced analgesic methods, which should be based on the expected time course of acute postoperative pain severity and aimed at time points where basic analgesia has proven insufficient. METHODS: We conducted a systematic search of the literature of analgesic trials for total hip arthroplasty (THA), extracting and pooling pain scores across studies, weighted for study size. Patients were grouped according to basic anaesthetic method used (general, spinal), and adjuvant analgesic interventions such as nerve blocks, local infiltration analgesia, and multimodal analgesia. Special consideration was given to high-risk populations such as chronic pain or opioid-dependent patients. RESULTS: We identified and analysed 71 trials with 5973 patients and constructed pain trajectories from the available pain scores. In most patients undergoing THA under general anaesthesia on a basic analgesic regimen, postoperative acute pain recedes to a mild level (<4/10) by 4 h after surgery. We note substantial variability in pain intensity even in patients subjected to similar analgesic regimens. Chronic pain or opioid-dependent patients were most often actively excluded from studies, and never analysed separately. CONCLUSIONS: We have demonstrated that it is feasible to construct procedure-specific pain curves to guide clinicians on the timing of advanced analgesic measures. Acute intense postoperative pain after THA should have resolved by 4-6 h after surgery in most patients. However, there is a substantial gap in knowledge on the management of patients with chronic pain and opioid-dependent patients.

Ultrasound-guided supraclavicular vs. retroclavicular block of the brachial plexus: comparison of ipsilateral diaphragmatic function: A randomised clinical trial.

BACKGROUND: The ultrasound-guided retroclavicular block (RCB) is a recently described alternative approach to brachial plexus blockade at the level of the cords. Although more distal blockade of the brachial plexus is thought to be associated with a lower incidence of phrenic nerve block, the impact of RCB on ipsilateral diaphragmatic function has not been formally investigated. OBJECTIVE: To compare the effects of supraclavicular and retroclavicular brachial plexus block on diaphragmatic function. SETTING: A single tertiary hospital, study period from December 2017 to May 2019. DESIGN: Double-blinded, randomised study. PATIENTS: A total of 40 patients undergoing upper extremity surgery below the axilla. Exclusion criteria included significant pulmonary disease, BMI more than 40 and contra-indication to peripheral nerve block. INTERVENTIONS: Patients were randomised to supraclavicular or retroclavicular brachial plexus block with ropivacaine 0.5%. OUTCOME MEASURES: Phrenic block was assessed by measuring changes in diaphragmatic excursion using M-mode ultrasound, and maximum inspiratory volume on incentive spirometry from baseline, at 15 and 30 min postblock, and postoperatively. Comparative assessment of block characteristics included timing and distribution of sensory and motor block onset in the upper extremity, and scanning and block performance times. RESULTS: The incidence of phrenic block in the supraclavicular group was higher by ultrasound imaging (70 vs. 15%) and also by pulmonary function testing (55 vs. 5%), with both diaphragmatic excursion and maximum inspiratory volume decreasing to a greater extent after supraclavicular block (SCB) compared with RCB at 15, 30 min and postoperative time points (repeated measures analysis of variance, P < 0.001). There was no difference in timing and extent of distal arm block, but suprascapular and axillary nerves were more consistently blocked after SCB than after RCB. CONCLUSION: The current study confirms the hypothesis that a RCB is significantly less likely to affect ipsilateral diaphragmatic function than a SCB. TRIAL REGISTRATION: Clinicaltrials.gov identifier: NCT02631122.

Risk of Major Complications After Perioperative Norepinephrine Infusion Through Peripheral Intravenous Lines in a Multicenter Study.

BACKGROUND: Continuous infusions of norepinephrine to treat perioperative hypotension are typically administered through a central venous line rather than a peripheral venous catheter to avoid the risk of localized tissue necrosis in case of drug extravasation. There is limited literature to estimate the risk of skin necrosis when peripheral norepinephrine is used to counteract anesthesia-associated hypotension in elective surgical cases. This study aimed to estimate the rate of occurrence of drug-related adverse effects, including skin necrosis requiring surgical management when norepinephrine peripheral extravasation occurs. METHODS: This retrospective cohort study used the perioperative databases of the University Hospitals in Amsterdam and Utrecht, the Netherlands, to identify surgical patients who received norepinephrine peripheral intravenous infusions (20 µg/mL) between 2012 and 2016. The risk of drug-related adverse effects, including skin necrosis, was estimated. Particular care was taken to identify patients who needed plastic surgical or medical attention secondary to extravasation of dilute, peripheral norepinephrine. RESULTS: A total of 14,385 patients who received norepinephrine peripheral continuous infusions were identified. Drug extravasation was observed in 5 patients (5/14,385 = 0.035%). The 95% confidence interval (CI) for infusion extravasation was 0.011%-0.081%, indicating an estimated risk of 1-8 events per every 10,000 patients. There were zero related complications requiring surgical or medical intervention, resulting in a 95% CI of 0%-0.021% and indicating a risk of approximately 0-2 events per 10,000 patients. CONCLUSIONS: In the current database analysis, no significant association was found between the use of peripheral intravenous norepinephrine infusions and adverse events.

The demographics of persistent opioid consumption following limb amputation.

BACKGROUND: Patients who have limb amputation are at risk of chronic pain, including phantom limb pain that can be challenging to treat. The aim of this study was to describe the incidence of pre-operative opioid usage and the incidence and risk factors for new persistent post-operative opioid usage in opioid-naïve patients after limb amputation. METHODS: A retrospective study of all patients 18 years and older underwent upper or lower extremity amputations in Landspitali University Hospital between 2005 and 2015. Patients were considered to use opioids pre-operatively if they filled an opioid prescription 1-6 months prior to amputation and were considered to have persistent opioid use if opioid prescriptions were filled between post-operative months four to twenty-four. In addition to incidence estimate, uni- and multivariate analysis was performed to identify risk factors for persistent post-operative opioid usage. RESULTS: Of 328 total patients, 216 (66%) were opioid naïve and 112 (34%) were chronic opioid users. Of the opioid-naïve patients surviving more than 3 months 40 (20%) developed persistent post-operative opioid usage. In multivariate analysis, factors independently associated with persistent post-operative opioid usage were younger age, male gender, pre-operative use of neuropathic medications or benzodiazepines and lower (opposed to upper) extremity amputation. CONCLUSION: Opioid naïve patients undergoing major amputation had a 20% chance of having a persistent opioid requirement following surgery. This could represent new-onset phantom limb pain or other chronic pain. Our findings should encourage perioperative multimodal efforts to reduce the burden of chronic pain after limb amputations.

Haematoma, abscess or meningitis after neuraxial anaesthesia in the USA and the Netherlands: A closed claims analysis.

BACKGROUND: Severe complications after neuraxial anaesthesia are rare but potentially devastating. OBJECTIVE: We aimed to identify characteristics and preventable causes of haematoma, abscess or meningitis after neuraxial anaesthesia. DESIGN: Observational study, closed claims analysis. SETTING: Closed anaesthesia malpractice claims from the USA and the Netherlands were examined from 2007 until 2017. PATIENTS: Claims of patients with haematoma (n = 41), abscess (n = 18) or meningitis (n = 14) associated with neuraxial anaesthesia for labour, acute and chronic pain that initiated and closed between 2007 and 2017 were included. There were no exclusions. MAIN OUTCOME MEASURES: We analysed potential preventable causes in patient-related, neuraxial procedure-related, treatment-related and legal characteristics of these complications. RESULTS: Patients experiencing spinal haematoma were predominantly above 60 years of age and using antihaemostatic medication, whereas patients with abscess or meningitis were middle-aged, relatively healthy and more often involved in emergency interventions. Potential preventable causes of unfavourable sequelae constituted errors in timing/prescription of antihaemostatic medication (10 claims, 14%), unsterile procedures (n = 10, 14%) and delay in diagnosis/treatment of the complication (n = 18, 25%). The number of claims resulting in payment was similar between countries (USA n = 15, 38% vs. the Netherlands n = 17, 52%; P = 0.25). The median indemnity payment, which the patient received varied widely between the USA (&OV0556;285 488, n = 14) and the Netherlands (&OV0556;31 031, n = 17) (P = 0.004). However, the considerable differences in legal systems and administration of expenses between countries may make meaningful comparison of indemnity payments inappropriate. CONCLUSIONS: Claims of spinal haematoma were often related to errors in antihaemostatic medication and delay in diagnosis and/or treatment. Spinal abscess claims were related to emergency interventions and lack of sterility. We wish to highlight these potential preventable causes, both when performing the neuraxial procedure and during postprocedural care of patients.

Insights into postoperative respiration by using continuous wireless monitoring of respiratory rate on the postoperative ward: a cohort study.

Change of respiratory rate (RespR) is the most powerful predictor of clinical deterioration. Brady- (RespR ≤ 8) and tachypnea (RespR ≥ 31) are associated with serious adverse events. Simultaneously, RespR is the least accurately measured vital parameter. We investigated the feasibility of continuously measuring RespR on the ward using wireless monitoring equipment, without impeding mobilization. Continuous monitoring of vital parameters using a wireless SensiumVitals® patch was installed and RespR was measured every 2 mins. We defined feasibility of adequate RespR monitoring if the system reports valid RespR measurements in at least 50% of time-points in more than 80% of patients during day- and night-time, respectively. Data from 119 patients were analysed. The patch detected in 171,151 of 227,587 measurements valid data for RespR (75.2%). During postoperative day and night four, the system still registered 68% and 78% valid measurements, respectively. 88% of the patients had more than 67% of valid RespR measurements. The RespR's most frequently measured were 13-15; median RespR was 15 (mean 16, 25th- and 75th percentile 13 and 19). No serious complications or side effects were observed. We successfully measured electronically RespR on a surgical ward in postoperative patients continuously for up to 4 days post-operatively using a wireless monitoring system. While previous studies mentioned a digit preference of 18-22 for RespR, the most frequently measured RespR were 13-16. However, in the present study we did not validate the measurements against a reference method. Rather, we attempted to demonstrate the feasibility of achieving continuous wireless measurement in patients on surgical postoperative wards. As the technology used is based on impedance pneumography, obstructive apnoea might have been missed, namely in those patients receiving opioids post-operatively.

Preperitoneal or Subcutaneous Wound Catheters as Alternative for Epidural Analgesia in Abdominal Surgery: A Systematic Review and Meta-analysis.

OBJECTIVE: To assess whether the location of wound catheters (ie, preperitoneal vs. subcutaneous) impacts outcomes, when compared with alternatives such as epidural analgesia. BACKGROUND: Continuous wound infiltration is an alternative for epidural analgesia in abdominal surgery but studies have shown conflicting results. This difference could be explained by different efficacy of preperitoneal versus subcutaneous placement of the infiltrative catheters. METHODS: A systematic review and meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines until April 3, 2017. Primary endpoints were pain scores in rest and when moving at 24 hours postoperatively. Secondary endpoints included postoperative pain scores at 12 and 48 hours, functional recovery, pain treatment-related complications, and patient satisfaction. RESULTS: After screening 2283 studies, 29 randomized controlled trials (RCTs) with 2059 patients were included. Methodological quality of these RCTs ranged from moderate to high. In the one direct comparison (60 patients), preperitoneal catheters led to better pain control than subcutaneous catheters. Superiority of preperitoneal compared with subcutaneous placement was confirmed indirectly in placebo-controlled RCTs. Preperitoneal wound catheters provided comparable pain control compared with active controls, such as epidural analgesia. Recovery parameters, opioid consumption, incidence of hypotension, and patient satisfaction seemed to be in favor of preperitoneal wound catheters compared with active alternatives, as well as placebo. CONCLUSION: Continuous wound infiltration with preperitoneal wound catheters is an effective pain modality in abdominal surgery. Pain control is as effective as epidural analgesia, but could be favored based upon recovery parameters and patient satisfaction.

Benefit of regional anaesthesia on postoperative pain following mastectomy: the influence of catastrophising.

BACKGROUND: Previous studies suggest that truncal regional anaesthesia (TRA), including techniques such as paravertebral block, may contribute significantly to analgesia after mastectomy. However, the severity and impact of postoperative pain varies markedly amongst individuals, making the identification of patients who would benefit most from TRA a potentially important step toward personalised perioperative care. METHODS: In this prospective observational study, mastectomy patients (n=122) were recruited and systematically assessed for psychosocial characteristics including pain catastrophising before surgery, and either received preoperative TRA (n=57) or no block (n=65). RESULTS: Age, baseline pain, and psychosocial traits did not differ between these groups. TRA was associated with lower overall pain scores and opioid consumption perioperatively, with a larger proportion of patients without block (50% vs 28%) reporting moderate-severe pain (more than three/10) on the day of surgery. Mixed model analysis of variance revealed a significant interaction between catastrophising and TRA, such that amongst patients with high baseline catastrophising, TRA was associated with substantially lower pain severity score (58% lower), while amongst patients with low baseline catastrophising, TRA was associated with only 18% lower pain severity. At 2 weeks, this interaction between baseline catastrophising and TRA was also observed when examining surgical pain burden, with higher baseline catastrophising patients who had received TRA reporting lower pain and less frequent opioid use (40% vs 70% of patients). CONCLUSIONS: TRA provided immediate analgesic benefit for patients undergoing mastectomy on the day of surgery, but this effect appeared more pronounced and sustained amongst patients with higher baseline catastrophising. CLINICAL TRIAL REGISTRATION: NCT02329574.

Molecular mechanisms of action of systemic lidocaine in acute and chronic pain: a narrative review.

Systemic administration of the local anaesthetic lidocaine is antinociceptive in both acute and chronic pain states, especially in acute postoperative and chronic neuropathic pain. These effects cannot be explained by its voltage-gated sodium channel blocking properties alone, but the responsible mechanisms are still elusive. This narrative review focuses on available experimental evidence of the molecular mechanisms by which systemic lidocaine exerts its clinically documented analgesic effects. These include effects on the peripheral nervous system and CNS, where lidocaine acts via silencing ectopic discharges, suppression of inflammatory processes, and modulation of inhibitory and excitatory neurotransmission. We highlight promising objectives for future research to further unravel these antinociceptive mechanisms, which subsequently may facilitate the development of new analgesic strategies and therapies for acute and chronic pain.

Comparison of perioperative glucose regulation in patients with type 1 vs type 2 diabetes mellitus: A retrospective cross-sectional study.

BACKGROUND: Most perioperative diabetes mellitus (DM) guidelines do not distinguish between patients with type 1 (DM1) and type 2 (DM2). We hypothesised that similar treatment of DM1 and DM2 patients leads to differences in their perioperative glucose control. METHODS: We performed a retrospective cross-sectional study, of all DM patients undergoing surgery between May 2013 and November 2015 in a Dutch university hospital. We compared DM1 with DM2 patients, treated according to the same perioperative glucose protocol. Our primary outcome was the incidence of hyperglycaemia (glucose ≥10 mmol/L). Secondary outcomes were short-term glycaemic control (glucose before surgery and peak glucose perioperatively), long-term glycaemic control (HbA1c in 90 days before and after surgery) and the incidence of hypoglycaemia (glucose <4 mmol/L). RESULTS: We included 2259 patients with DM, 216 (10%) of which had DM1. The calculated incidences in our population were 7 out of 1000 patients with DM1 and 69 out of 1000 patients with DM2. Compared to those with DM2, patients with DM1 were younger, had a lower BMI, a higher glucose concentration before surgery, and a higher perioperative peak glucose concentration (11.0 [8.2-14.7] vs 9.4 [7.7-11.7], P < 0.001). The incidence of the primary endpoint, perioperative hyperglycaemia, was significantly higher in DM1 compared to DM2 patients (63% vs 43%, P < 0.001). Hypoglycaemia occurred more often in the DM1 population (7.1% vs 1.3%, P < 0.001). CONCLUSION: Providing similar perioperative treatment to patients with DM1 and DM2 is associated with poorer short-term and long-term glycaemic control in DM1 throughout the perioperative period as well as an increased risk of hypoglycaemia.

Paracetamol versus other analgesia in adult patients with minor musculoskeletal injuries: a systematic review.

OBJECTIVES: Pain treatment in acute musculoskeletal injuries usually consists of paracetamol, non-steroidal antiinflammatory drugs (NSAIDs) or opioids. It would be beneficial to determine whether paracetamol is as effective as other analgesics. The objective of this study was to evaluate available evidence regarding efficacy of paracetamol in these patients. METHODS: Embase, MEDLINE, Cochrane and relevant trial registers were searched from inception to 14 February 2018 by two independent reviewers to detect all randomised studies with adult patients with acute minor musculoskeletal injuries treated with paracetamol as compared with other analgesics. There were no language or date restrictions. Two independent reviewers evaluated risk of bias and quality of evidence. Primary outcome was decrease in pain scores during the first 24 hours, and secondary outcomes included pain decrease beyond 24 hours, need for additional analgesia and occurrence of adverse events. RESULTS: Seven trials were included, evaluating 2100 patients who were treated with paracetamol or NSAIDs or the combination of both as comparisons, of which only four studies addressed the primary outcome. No studies were found comparing paracetamol with opioids. There were no differences in analgesic effectiveness within and beyond 24 hours, nor in need for additional analgesia and occurrence of adverse events. Overall, quality of evidence was low. Because of methodological inconsistencies, a meta-analysis was not possible. CONCLUSIONS: Based on available evidence, paracetamol is as effective as NSAIDs or the combination of both in treating pain in adult patients with minor musculoskeletal injuries in the acute setting. The quality of evidence is low.

Pharmacodynamics and Pharmacokinetics of Lidocaine in a Rodent Model of Diabetic Neuropathy.

BACKGROUND: Clinical and experimental data show that peripheral nerve blocks last longer in the presence of diabetic neuropathy. This may occur because diabetic nerve fibers are more sensitive to local anesthetics or because the local anesthetic concentration decreases more slowly in the diabetic nerve. The aim of this study was to investigate both hypotheses in a rodent model of neuropathy secondary to type 2 diabetes. METHODS: We performed a series of sciatic nerve block experiments in 25 Zucker Diabetic Fatty rats aged 20 weeks with a neuropathy component confirmed by neurophysiology and control rats. We determined in vivo the minimum local anesthetic dose of lidocaine for sciatic nerve block. To investigate the pharmacokinetic hypothesis, we determined concentrations of radiolabeled (C) lidocaine up to 90 min after administration. Last, dorsal root ganglia were excised for patch clamp measurements of sodium channel activity. RESULTS: First, in vivo minimum local anesthetic dose of lidocaine for sciatic nerve motor block was significantly lower in diabetic (0.9%) as compared to control rats (1.4%). Second, at 60 min after nerve block, intraneural lidocaine was higher in the diabetic animals. Third, single cell measurements showed a lower inhibitory concentration of lidocaine for blocking sodium currents in neuropathic as compared to control neurons. CONCLUSIONS: We demonstrate increased sensitivity of the diabetic neuropathic nerve toward local anesthetics, and prolonged residence time of local anesthetics in the diabetic neuropathic nerve. In this rodent model of neuropathy, both pharmacodynamic and pharmacokinetic mechanisms contribute to prolonged nerve block duration.

Acetaminophen or Nonsteroidal Anti-Inflammatory Drugs in Acute Musculoskeletal Trauma: A Multicenter, Double-Blind, Randomized, Clinical Trial.

STUDY OBJECTIVE: We determine whether pain treatment with acetaminophen was not inferior to nonsteroidal anti-inflammatory drugs or the combination of both in minor musculoskeletal trauma. METHODS: The Paracetamol or NSAIDs in Acute Musculoskeletal Trauma Study was a double-blind, randomized, clinical trial conducted in 2 general practices and 2 emergency departments in the Netherlands. A total of 547 adults, aged 18 years and older, with acute blunt minor musculoskeletal extremity trauma were randomly assigned in a 1:1:1 ratio to acetaminophen 4,000 mg/day, diclofenac 150 mg/day, or acetaminophen 4,000 mg/day+diclofenac 150 mg/day during 3 consecutive days. Patients, health care staff, and outcome assessors were blinded for treatment allocation. Follow-up for each patient was 30 days. Primary outcome measures were between-group differences in mean numeric rating scale (NRS) pain scores in rest and with movement at 90 minutes after initial drug administration compared with baseline pain scores with a predefined noninferiority margin of 0.75 NRS points. Secondary outcomes included NRS pain scores during 3 consecutive days and need for additional analgesia. RESULTS: One hundred eighty-two patients were treated with acetaminophen, 183 with diclofenac, and 182 with combination treatment. Intention-to-treat analysis revealed mean NRS reduction in rest -1.23 (95% confidence interval [CI] -1.50 to -0.95) and -1.72 (95% CI -2.01 to -1.44) with movement, both for acetaminophen at 90 minutes compared with baseline. Pairwise comparison in rest with diclofenac showed a difference of -0.027 (97.5% CI -0.45 to 0.39) and -0.052 (97.5% CI -0.46 to 0.36) for combination treatment. With movement, these numbers were -0.20 (97.5% CI -0.64 to 0.23) and -0.39 (97.5% CI -0.80 to 0.018), respectively. All differences were well below the predefined noninferiority margin. CONCLUSION: Pain treatment with acetaminophen was not inferior to that with diclofenac or the combination of acetaminophen and diclofenac in acute minor musculoskeletal extremity trauma, both in rest and with movement.

The Science of Local Anesthesia: Basic Research, Clinical Application, and Future Directions.

Local anesthetics have been used clinically for more than a century, but new insights into their mechanisms of action and their interaction with biological systems continue to surprise researchers and clinicians alike. Next to their classic action on voltage-gated sodium channels, local anesthetics interact with calcium, potassium, and hyperpolarization-gated ion channels, ligand-gated channels, and G protein-coupled receptors. They activate numerous downstream pathways in neurons, and affect the structure and function of many types of membranes. Local anesthetics must traverse several tissue barriers to reach their site of action on neuronal membranes. In particular, the perineurium is a major rate-limiting step. Allergy to local anesthetics is rare, while the variation in individual patient's response to local anesthetics is probably larger than previously assumed. Several adjuncts are available to prolong sensory block, but these typically also prolong motor block. The 2 main research avenues being followed to improve action of local anesthetics are to prolong duration of block, by slow-release formulations and on-demand release, and to develop compounds and combinations that elicit a nociception-selective blockade.

Trends in practice and safety measures of epidural analgesia: Report of a national survey.

BACKGROUND: The clinical use of epidural analgesia has changed over past decades. Minimally invasive surgery and emergence of alternative analgesic techniques have led to an overall decline in its use. In addition, there is increasing awareness of the patient-specific risks for complications such as spinal haematoma and abscess. Local guidelines for management of severe neurological complications during or after epidural analgesia, ie, "epidural alert systems", have been introduced in hospitals to coordinate and potentially streamline early diagnosis and treatment. How widely such protocols have been implemented in daily practice is unknown. METHODS: We conducted a survey to analyse trends in practice, key indications, safety measures, safety reporting, and management of complications of epidural analgesia in the Netherlands. Data were gathered using a web-based questionnaire and analysed using descriptive statistics. RESULTS: Questionnaires from 85 of all 94 Dutch hospitals performing epidural analgesia were collected and analysed, a 90% response rate. Fifty-five percent reported a trend towards decreased use of perioperative epidural analgesia, while 68% reported increasing use of epidural analgesia for labour. Reported key indications for epidural analgesia were thoracotomy, upper abdominal laparotomy, and abdominal cancer debulking. An epidural alert system for neurological complications of epidural analgesia was available in 45% of hospitals. CONCLUSIONS: This national audit concerning use and safety of epidural analgesia demonstrates that a minority of Dutch hospitals have procedures to manage suspected neurological complications of epidural analgesia, whereas in the remaining hospitals responsibilities and timelines for management of epidural emergencies are determined on an ad hoc basis.

NMDA Receptor Antagonist Ketamine Distorts Object Recognition by Reducing Feedback to Early Visual Cortex.

It is a well-established fact that top-down processes influence neural representations in lower-level visual areas. Electrophysiological recordings in monkeys as well as theoretical models suggest that these top-down processes depend on NMDA receptor functioning. However, this underlying neural mechanism has not been tested in humans. We used fMRI multivoxel pattern analysis to compare the neural representations of ambiguous Mooney images before and after they were recognized with their unambiguous grayscale version. Additionally, we administered ketamine, an NMDA receptor antagonist, to interfere with this process. Our results demonstrate that after recognition, the pattern of brain activation elicited by a Mooney image is more similar to that of its easily recognizable grayscale version than to the pattern evoked by the identical Mooney image before recognition. Moreover, recognition of Mooney images decreased mean response; however, neural representations of separate images became more dissimilar. So from the neural perspective, unrecognizable Mooney images all "look the same", whereas recognized Mooneys look different. We observed these effects in posterior fusiform part of lateral occipital cortex and in early visual cortex. Ketamine distorted these effects of recognition, but in early visual cortex only. This suggests that top-down processes from higher- to lower-level visual areas might operate via an NMDA pathway.

Perioperative Anesthesia Care and Tumor Progression.

This narrative review discusses the most recent up-to-date findings focused on the currently available "best clinical practice" regarding perioperative anesthesia care bundle factors and their effect on tumor progression. The main objective is to critically appraise the current literature on local anesthetics, regional outcome studies, opioids, and nonsteroidal anti-inflammatory drugs (NSAIDs) and their ability to decrease recurrence in patients undergoing cancer surgery. A brief discussion of additional topical perioperative factors relevant to the anesthesiologist including volatile and intravenous anesthetics, perioperative stress and anxiety, nutrition, and immune stimulation is included. The results of several recently published systematic reviews looking at the association between cancer recurrences and regional anesthesia have yielded inconclusive data and provide insufficient evidence regarding a definitive benefit of regional anesthesia. Basic science data suggests an anti tumor effect induced by local anesthetics. New refined animal models show that opioids can safely be used for perioperative pain management. Preliminary evidence suggests that NSAIDs should be an essential part of multimodal analgesia. Volatile anesthetics have been shown to increase tumor formation, whereas preclinical and emerging clinical data from propofol indicate tumor protective qualities. The perioperative period in the cancer patient represents a unique environment where surgically mediated stress response leads to immune suppression. Regional anesthesia techniques when indicated in combination with multimodal analgesia that include NSAIDs, opioids, and local anesthetics to prevent the pathophysiologic effects of pain and neuroendocrine stress response should be viewed as an essential part of balanced anesthesia.