Toxicity of local anaesthetics

The complications of failure, neural injury and local anaesthetic toxicity are common to all regional anaesthetic techniques, and individual techniques are associated with specific complications. All potential candidates for regional anaesthesia should be thoroughly evaluated and informed of potential complications. Central neural blockades still account for more than 70% of regional anaesthesia procedures. Permanent neurological injury is 0.02-0.07%. Pain on injection and paraesthesias while performing regional anaesthesia are danger signals of potential injury and must not be ignored. The incidence of systemic toxicity to local anaesthetics has significantly decreased in the past 30 years, from 0.2 to 0.01%. Peripheral nerve blocks are associated with the highest incidence of systemic toxicity (7.5 per 10,000) and the lowest incidence of serious neural injury (1.9 per 10,000).     

近红外光谱监测在先天性心脏病患儿围术期应用的研究进展

先天性心脏病是儿童最常见的心脏病,大部分先天性心脏病患儿需及时进行手术治疗矫正畸形。然而,术后脑损伤和神经发育不良一直是心肺转流下先天性心脏病手术后常见的神经系统并发症,严重影响患儿的预后。有效的监测手段对于积极预防、尽早发现和及时处理神经系统并发症至关重要。应用近红外光谱(NIRS)监测局部脑组织氧饱和度(rScO₂),或联合其他脑神经功能监测手段进行多模式监测,有助于及时发现脑缺血缺氧不良事件,进而循序调整影响因素进行干预,有利于降低术后神经损伤的发生率,改善患儿预后。本文就NIRS的原理、影响因素及其在先天性心脏病患儿围术期单独应用和与其他监测方法联合应用进行综述,旨在为先天性心脏病患儿围术期脑神经功能监测提供参考。     

Perioperative management of familial dysautonomia: a systematic review

BACKGROUND AND OBJECTIVE: Familial dysautonomia (FD), a rare genetic disorder, is characterized by autonomic instability, pulmonary infections, oesophageal dysmotility, spinal abnormalities and episodic "dysautonomic crisis" characterized by rash, vomiting, sweating and hypertension. Frequent anaesthetic complications have been reported. METHODS: We performed a comprehensive literature search of perioperative management of FD using an OVID-based search strategy. Identified reports were reviewed to identify perioperative complications as well as anaesthetic techniques and perioperative management strategies developed to minimize or prevent these complications. RESULTS: Eighteen case reports or series of perioperative management of FD were identified in the literature for a total of 179 patients undergoing 290 anaesthetics. Intraoperative cardiovascular lability, including cardiac arrests and postoperative pulmonary complications were commonly reported. Preoperative hydration, minimizing the use of volatile anaesthetic agents, postoperative ventilation, use of regional anaesthesia and minimally invasive surgical techniques reduced the incidence of these complications. CONCLUSIONS: While patients with FD are reported to have a relatively high rate of various perioperative complications, a full understanding of its pathophysiology can be used to develop a perioperative management strategy to anticipate and prevent many of these complications.     

Intraoperative neurological changes in 1665 regional anaesthetic carotid endarterectomies predicts postoperative stroke

BACKGROUND: To maximize the benefit of carotid endarterectomy (CEA) in stroke prevention its complication rate must be minimized. The purpose of this study was to report the outcomes of a large series of CEA carried out under regional anaesthesia with selective shunting, with particular emphasis on identifying predictors for perioperative stroke and mortality. METHODS: Between 1987 and 2003 the data for 1665 consecutive regional anaesthetic CEA carried out in 1495 patients were collected prospectively; awake neurological testing facilitated selective shunting. Preoperative data, intraoperative events and postoperative in-hospital complications were recorded and analysed. RESULTS: There were 38 non-fatal strokes (2.3%) and 10 deaths (0.6%), giving a combined stroke and mortality rate of 2.9%. Only patients who needed shunting were found to have significantly higher rate of postoperative stroke and mortality (7.0 vs 1.9%, P < 0.001). Patient characteristics, comorbidities, indication for operation (P = 0.34) and the degree of stenosis of the contralateral carotid artery (P = 0.65) were not found to be predictive of perioperative stroke or mortality, although the latter two were found to be predictive of the need for shunting (P < 0.001 and P = 0.002). CONCLUSION: Regional anaesthetic CEA is a safe and effective technique with excellent morbidity and mortality rates. The technique can be undertaken safely regardless of the indication for endarterectomy or the status of the contralateral carotid artery. Patients who developed intraoperative neurological changes requiring shunting are identified as high risk for perioperative stroke or mortality and should therefore be carefully monitored postoperatively.     

Spinal anaesthesia for spinal surgery

Spinal anaesthesia for spinal surgery is becoming increasingly more popular because this anaesthetic technique allows the patient to self-position and avoid neurological injury that may occur with prone positioning under general anaesthesia. Spinal anaesthesia reduces intraoperative surgical blood loss, improves perioperative haemodynamic stability and reduces pain in the immediate postoperative period. This leads to a reduced need for analgesics and a reduction in the incidence of nausea and vomiting in the postoperative setting. Spinal anaesthesia for lumbar spine surgery also decreases the incidence of lower extremity thrombo-embolic complications and does not increase the occurrence of problems with micturition. These benefits increase the patient's satisfaction, and they expedite discharge of the patient from the hospital. Combination anaesthetic techniques, using both subarachnoid and epidural dosing schemes, may be beneficial for improving postoperative pain control and add further to the benefit of spinal anaesthesia for lumbar spine surgical procedures.     

区域阻滞麻醉与老年患者术后神经系统功能、病死率关系的研究进展

背景 区域阻滞麻醉应用于老年患者手术日益增多,其对老年患者术后神经系统功能、病死率的影响有待总结. 目的 通过文献综述,分析区域阻滞麻醉对老年患者术后神经系统、病死率的影响. 内容 讨论区域阻滞麻醉与老年患者术后神经系统功能,包括术后谵妄、认知功能障碍、脑卒中以及与病死率之间的关系. 趋向 区域阻滞麻醉可以减少老年患者术后肺部并发症,减少术后早期认知功能障碍,与全身麻醉相比,具有一定优势.区域阻滞麻醉是否能降低老年患者术后病死率、心血管并发症发生率、谵妄发生率、围手术期脑卒中发生率尚有待于进一步研究.     

Complications of regional anaesthesia

Complications of regional anaesthesia can be divided into those specific to central neuraxial blockade, those specific to peripheral nerve blockade, and those that pertain to both. Fortunately, severe complications, namely spinal cord damage, vertebral cord haematoma and epidural abscess are rare. Here we have given an overview of these complications, with reference to incidences available following the 3rd National Audit Project of the Royal College of Anaesthetists. A thorough knowledge of anatomy and pharmacology, and a meticulous, unhurried technique are key to reducing the risk of such complications. When considering the use of a regional anaesthetic technique, the risks and benefits for the individual patient should be assessed on a case-by-case basis, and set against the risks and benefits of alternatives.     

Strategies in the patient with compromised respiratory function

Respiratory diseases are commonly divided into restrictive or obstructive lung diseases. For anaesthesiological considerations restrictive lung diseases appear as a static condition with minimal short-term development. Overall, restrictive lung diseases don't lead to acute exacerbations due to the choice of anaesthetic techniques or the choice of anaesthesia-specific agents. Compared to restrictive lung diseases, obstructive lung diseases such as asthma or chronic obstructive lung diseases have a high prevalence and are one of the four most frequent causes of death. Obstructive lung diseases can be significantly influenced by the choice of anaesthetic technique and anaesthetic agent. Basically, the severity of the chronic obstructive pulmonary disease (COPD) and the degree of bronchial hyperreactivity will determine the perioperative anaesthetic risk. This risk has to be assessed by a thorough preoperative evaluation and will provide the rationale on which to decide the adequate anaesthetic technique. In particular, airway instrumentation can cause severe reflex bronchoconstriction. The use of regional anaesthesia alone or in combination with general anaesthesia can help to avoid airway irritation and even leads to reduced postoperative complications. Prophylactic anti-obstructive treatment, volatile anaesthetics, propofol, opioids, and an adequate choice of muscle relaxants minimize the anaesthetic risk when general anaesthesia is required. If intraoperative bronchospasm occurs, despite all precautions, deepening of anaesthesia, repeated administration of β₂-adrenergic agents and parasympatholytics, and a single systemic dose of corticosteroids are the main treatment options.     

Complications of regional anaesthesia

Complications of regional anaesthesia can be divided into those specific to central neuraxial blockade, those specific to peripheral nerve blockade, and those that pertain to both. Fortunately, severe complications, namely spinal cord damage, vertebral cord haematoma and epidural abscess, are rare. Here we have given an overview of these complications, with reference to incidences available following the Third National Audit Project of the Royal College of Anaesthetists. A thorough knowledge of anatomy and pharmacology, and a meticulous, unhurried technique are key to reducing the risk of such complications. When considering the use of a regional anaesthetic technique, the risks and benefits for the individual patient should be assessed on a case-by-case basis, and set against the risks and benefits of alternatives.     

Neurological conditions in the perioperative period

The wide spectrum of neurological disorders and their effects on the function of the central and peripheral nervous system can cause an extensive array of symptoms and significant morbidity and mortality. Morbidity and mortality are often amplified in the perioperative period with an elevated risk of anaesthetic complications and adverse events. However, the number of patients with neurological disease requiring surgery is unlikely to diminish, and therefore this anaesthetic risk needs to be met and managed effectively. Here we aim to examine a range of different neurological conditions, exploring the possible complications and complexities encountered in the perioperative period, in addition to discussing strategies to minimize the risk of adverse outcomes and ensure the delivery of safe anaesthesia and good perioperative care.     

Anaesthesia for patients with intracranial hypertension due to cerebral oedema

The main objective for anaesthesia in patients with intracranial hypertension (ICH) is to maintain the cerebral perfusion pressure (CPP). Before the operation, the assessment of the level of intracranial pressure relies on the Glasgow coma score and the signs of ICH on the CT-scan. In the perioperative period, repeated transcranial Doppler examinations may help in determining the adequate CPP. Haemodynamic and respiratory complications are common after subarachnoid haemorrhage or head injury. Careful preoperative screening of the cardiovascular and respiratory system is mandatory before anaesthesia. There is no recommended anaesthetic technique for patients with ICH. Nitrous oxide should be avoided in patients with severe ICH or during emergency surgery. Theoretically, intravenous anaesthesia is a better choice than inhalation anesthesia because of the cerebral vasodilatation induced by inhalation agents. In the most severe cases thiopental is the only anaesthetic agent to consider. Treatment of hypovolaemia with fluid loading and the early use of vasoactive agents can be recommended to maintain CPP. Before intracranial surgery, large doses of mannitol have been demonstrated to improve neurological recovery in brain injured patients. The urinary losses due to the infusion of mannitol should be replaced with isotonic saline. Emergence and extubation are best performed in the intensive care unit under close systemic and cerebral haemodynamic control.     

Perioperative tumour dissemination. 1. Influence of perioperative factors

There has been growing concern in the last few years on the effect of anaesthetic drugs used during oncological surgery could have on tumour progression in the long-term, as well as the influence of other perioperative factors. Although much of the available data has weak evidence, the role of the surgery itself, pain, transfusion of blood derivatives, etc., have been assessed in several studies. How some substances used during the anaesthetic process can influence tumour immune surveillance, cell proliferation or tumour angiogenesis processes have been observed in laboratory studies. The possible relevance of the anaesthetic technique used as regards the long-term tumour progression and survival is still to be determined. However, based on retrospective studies, it seems that those anaesthetic techniques combined with the use of regional anaesthesia and analgesia could be beneficial compared to those that are maintained on opioid use. Further research should help to elucidate the long-term clinical relevance of the perioperative procedures, including the anaesthetic, during oncological surgery.     

Neurological conditions in the perioperative period

The wide spectrum of neurological disorders and their effects on the function of the central and peripheral nervous system can cause an extensive array of symptoms and significant morbidity and mortality. This morbidity and mortality is often amplified in the perioperative period with an elevated risk of anaesthetic complications and adverse events. However, the number of patients with neurological disease requiring surgery is unlikely to diminish, and therefore this anaesthetic risk needs to be met and managed effectively. Here we aim to examine a range of different neurological conditions, exploring the possible complications and complexities encountered in the perioperative period, in addition to discussing strategies to minimize the risk of adverse outcomes and ensure the delivery of safe anaesthesia and good perioperative care.     

Complications of spinal and epidural anesthesia

In conclusion, major complications after neuraxial techniques are rare but can be devastating to the patient and the anesthesiologist. Prevention and management begin during the preoperative visit with a careful evaluation of the patient's medical history and appropriate preoperative discussion of the risks and benefits of the available anesthetic techniques. Alternative anesthetic techniques, such as peripheral regional techniques or general anesthesia, should be considered for patients at increased risk for neurologic complications following neuraxial block. The decision to perform a regional anesthetic technique on an anesthetized patient must be made with care, as these patients are unable to report pain on needle placement or injection of local anesthetic. Efforts should also be made to decrease neural injury in the operating room through careful patient positioning. Postoperatively, patients must be followed closely to detect potentially treatable sources of neurologic injury, including expanding spinal hematoma or epidural abscess, constrictive dressings, improperly applied casts, and increased pressure on neurologically vulnerable sites. New neurologic deficits should be evaluated promptly by a neurologist, or neurosurgeon, to document formally the patient's evolving neurologic status, arrange further testing or intervention, and provide long-term follow-up.     

Regional anaesthesia for orthopaedic procedures

Regional anaesthesia is apposite for orthopaedic surgery for anatomical reasons and to reduce complications from general anaesthesia. A reduction in pain scores, drowsiness and nausea can improve postoperative mobility and facilitate earlier hospital discharge. Disadvantages include block failure, nerve injury, possible loss of motor function and proprioception and local anaesthetic toxicity. Complications are rare but may be reduced by the use of ultrasound and nerve stimulation, performing the block on a conscious patient and stopping injection if there is pain or high resistance. Patients should be assessed preoperatively to rule out contraindications such as local infection or coagulopathy, and clear explanations of the procedure and any possible complications should be given. Patients should also be assessed postoperatively and any suspicious findings investigated promptly and followed up until there is complete resolution.     

Future of regional anaesthesia

The development and refinement of regional anaesthetic techniques for various types of surgery, mainly obstetric, ophthalmic and orthopaedic surgery, and of continuous regional analgesia continues. Suitable analgesic drug mixtures, and concentrations, will be further tested in order to find the ideal analgesic regimen for each type of surgery and for the individual patient. No new local anaesthetics or equipment for clinical use are expected in the near future. Improvement therefore depends much on how the anaesthesiologists use the present drugs, needles, nerve detection devices, catheters and pumps. During training in regional anaesthesia for the speciality of anaesthesiology and intensive care medicine, it may suffice to concentrate only on certain common techniques such as epidural block, spinal block, axillary brachial plexus block, intravenous regional anaesthesia and femoral nerve block. Rare regional anaesthetic blocks and invasive techniques should be mastered and taught by specially trained regional anaesthesiology experts. In chronic pain, regional anaesthetic blocks with local anesthetics are not expected to play any major therapeutic role. However, nerve blocks can be useful for diagnostic purposes and in order to facilitate rehabilitation in chronic pain syndromes.     

Continuous spinal anaesthesia for abdominal surgery in a patient receiving amiodarone

The perioperative management of a 57-yr-old patient receiving chronic amiodarone therapy with a continuous spinal anaesthetic for a low anterior resection of the colon is discussed. The most appropriate anaesthetic technique for patients receiving chronic amiodarone therapy remains controversial, but the avoidance of general anaesthesia may be beneficial because of the risk of postoperative pulmonary failure. In this patient continuous spinal anaesthesia was slowly titrated to the desired level, coincident haemodynamic alterations were easily treated as they developed, and high serum local anaesthetic concentrations which occur with other regional anaesthetic techniques were avoided.     

区域麻醉或镇痛联合全麻的临床应用与争议

背景近年全麻手术中加入区域阻滞的应用日益增多。尽管有证据支持区域阻滞比全麻具有更好的镇痛作用,但其对总体术后转归的改善仍未完全清楚。目的评价区域阻滞对患者中长期术后转归的影响以及实施区域阻滞的风险和争议。内容硬膜外阻滞减少血管大手术或高危患者的心血管并发症;尽管区域阻滞对早期术后康复有一定改善,但对长期术后康复的影响不...     

Anaesthetic considerations for patients with a pre‐existing neurological deficit: are neuraxial techniques safe?

Pre-existing neurological and muscular disease may be a specific concern for anaesthetists as they need to consider the effect of anaesthesia upon the disease, vice versa, and the interaction of anaesthesia with the medication taken by the patient. Despite a lack of controlled studies, many anaesthetists, being afraid of a claim, will prefer general rather than regional anaesthesia in these patients. Nevertheless regional anaesthesia certainly merits its place because it offers undeniable advantages. A good pre-operative examination is very important while patients should also be informed about peri-operative implications of anaesthesia, surgery and stress. Paraesthesias, epinephrine and high concentrations of local anaesthetics should be avoided in the majority of the diseases. Some diseases may benefit from epidural anaesthesia while for others a spinal technique may be the technique of preference. Special attention should be paid to patients with spinal stenosis despite recent reassuring reports with respect to safety of regional anaesthetic techniques. Anaesthetists should not automatically take all responsibility in case of progressive or new deficit after the procedure.