Spinal anaesthesia

Spinal anaesthesia involves the injection of local anaesthetic solution into the intrathecal space. It is a widely practised anaesthetic technique that can provide surgical anaesthesia for procedures below the umbilicus. Due to the proximity of the central nervous system, safe practice is of paramount importance and requires a good understanding of relevant anatomy, physiology and pharmacology. Complications are rare but need to be recognized and managed rapidly and appropriately.     

Spinal anaesthesia

Spinal anaesthesia is the injection of local anaesthetic into the subarachnoid space. It is a simple technique that can be used to provide surgical anaesthesia for procedures involving the abdomen, pelvis and lower limbs. To perform the technique safely it is important to understand the physiology of the block and the pharmacology of the drugs commonly used. Although serious complications are rare, they must be recognized and managed quickly.     

Anaesthetic practice for groin hernia repair--a nation-wide study in Denmark 1998-2003

BACKGROUND: Recent scientific data suggest that local infiltration anaesthesia for inguinal hernia surgery may be preferable compared to general anaesthesia and regional anaesthesia, since it is cheaper and with less urinary morbidity. Regional anaesthesia may have specific side-effects and is without documented advantages on morbidity in this small operation. METHODS: To describe the use of the three anaesthetic techniques for elective open groin hernia surgery in Denmark from January 1st 1998 to December 31st 2003, based on the Danish Hernia Database collaboration. RESULTS: In a total of 57,505 elective open operations 63.6% were performed in general anaesthesia, 18.3% in regional anaesthesia and 18.1% in local anaesthesia. Regional anaesthesia was utilized with an increased rate in elderly and hospitalized patients. Outpatient surgery was most common with local infiltration anaesthesia. CONCLUSION: Use/choice of anaesthesia for groin hernia repair is not in accordance with recent scientific data. Use of spinal anaesthesia should be reduced and increased use of local anaesthesia is recommended to enhance recovery and reduce costs.     

Total spinal anaesthesia as a complication of local anaesthetic test-dose administration through an epidural catheter

We describe a case of total spinal anaesthesia, which occurred after a 3-ml lignocaine (20 mg ml(-1)) test dose was administered through an epidural catheter in a 79-year-old patient scheduled for gastrectomy under combined general and epidural anaesthesia. The surgery was postponed, and the patient required admission to the intensive therapy unit. Spinal MRI from the total spinal cord did not reveal any pathology. During the next 24 h the patient recovered and after 11 days was successfully operated on under general anaesthesia. No late complications followed. We presume that during placement, the epidural catheter had migrated to the spinal canal as a result of technical difficulties. Although controversial, we consider that administering a standard test dose of local anaesthetic via an epidural catheter is recommended, especially in high-risk patients and when epidural space identification or catheter placement poses technical difficulties. A test dose of local anaesthetic does not fully prevent complications.     

Regional anaesthesia for caesarean section and what to do if it fails

Regional anaesthetic techniques are the most frequently used type of anaesthetic used for caesarean deliveries. They have a better safety profile than general anaesthesia in the pregnant woman. The choice of whether to use a spinal, epidural or combined spinal–epidural technique will depend on patient and surgical factors. Particular care is required in those receiving therapeutic anticoagulation or with clotting abnormalities. Women should be provided with information regarding the risks and intended benefits of the different techniques to make an informed choice regarding mode of anaesthesia. All women having caesarean deliveries must have vital sign monitoring, antacid prophylaxis and intraoperative venous thromboembolic prophylaxis. A left lateral tilt must be maintained until delivery of the baby to reduce the effects of aortocaval compression. Adequate anaesthesia must be confirmed prior to commencing surgery and strategies for managing failed spinal anaesthesia should be considered. Breakthrough pain during caesarean delivery is a distressing complication and must be addressed. General anaesthesia should be offered and, if declined, the woman's pain must be adequately managed with alternative analgesic methods. These include nitrous oxide, opioids and local anaesthetic infiltration.     

Regional anaesthesia for caesarean birth and what to do if it fails

Regional anaesthetic techniques are the most frequently used type of anaesthetic for caesarean births. They have a better safety pro?le than general anaesthesia in the pregnant woman. The choice of whether to use a spinal, epidural or combined spinal–epidural technique will depend on patient and surgical factors. Particular care is required in those receiving therapeutic anticoagulation or with clotting abnormalities. Women should be provided with information regarding the risks and intended bene?ts of the different techniques to make an informed choice regarding mode of anaesthesia. All women having caesarean births must have vital sign monitoring, antacid prophylaxis and intraoperative venous thromboembolic prophylaxis. A left lateral tilt must be maintained until delivery of the baby to reduce the effects of aortocaval compression. Adequate anaesthesia must be con?rmed prior to commencing surgery and strategies for managing failed spinal anaesthesia should be defined in local guidelines. Breakthrough pain during caesarean birth is a distressing complication and must be addressed. General anaesthesia should be offered and, if declined, the woman's pain must be adequately managed with alternative analgesic methods. These include nitrous oxide, opioids and local anaesthetic in?ltration.     

Spinal anaesthesia in infants and children

Every anaesthetist who deals with paediatric patients should have the expertise to perform spinal anaesthesia. Often, children undergoing surgery in the lower part of the body have contraindications for general anaesthesia; in these children spinal anaesthesia is a convenient option.The aim of anaesthesia is to provide good operating conditions for the surgeon while avoiding any harmful psychological sequelae for the child. In addition, the anaesthetist's goal is to lessen the physiological stress response to surgery and to prevent post-operative morbidity. In children, spinal anaesthesia produces a dense intra-operative analgesia and, when combined with general anaesthesia, it reduces the requirements for anaesthetic agents and opioids intra-operatively. Spinal anaesthesia allows a fast return to a bright and alert status, and a rapid return of normal appetite. Following spinal anaesthesia, analgesia continues into the early post-operative period, and nausea and vomiting are uncommon. Consequently, ambulation and discharge are not delayed.Some children develop complications following spinal anaesthesia—for example, a post-lumbar puncture headache and transient neurological symptoms. In young children these symptoms may be difficult to perceive if parents are not informed. When long-lasting, these symptoms may surpass the benefits of spinal anaesthesia and should therefore be identified and treated appropriately.     

Fundamentals and innovations in regional anaesthesia for infants and children

Regional anaesthesia in children has evolved rapidly in the last decade. Although it previously consisted of primarily neuraxial techniques, the practice now incorporates advanced peripheral nerve blocks, which were only recently described in adults. These novel blocks provide new avenues for providing opioid-sparing analgesia while minimising invasiveness, and perhaps risk, associated with older techniques. At the same time, established methods, such as infant spinal anaesthesia, under-utilised in the last 20 years, are experiencing a revival. The impetus has been the concern regarding the potential long-term neurocognitive effects of general anaesthesia in the young child. These techniques have expanded from single shot spinal anaesthesia to combined spinal/epidural techniques, which can now effectively provide surgical anaesthesia for procedures below the umbilicus for a prolonged period of time, thereby avoiding the need for general anaesthesia. Continuous 2-chloroprocaine infusions, previously only described for intra-operative regional anaesthesia, have gained popularity as a means of providing prolonged postoperative analgesia in epidural and continuous nerve block techniques. The rapid, liver-independent metabolism of 2-chloroprocaine makes it ideal for prolonged local anaesthetic infusions in neonates and small infants, obviating the increased risk of local anaesthetic systemic toxicity that occurs with amide local anaesthetics. Debate continues over certain practices in paediatric regional anaesthesia. While the rarity of complications makes comparative analyses difficult, data from large prospective registries indicate that providing regional anaesthesia to children while under general anaesthesia appears to be at least as safe as in the sedated or awake patient. In addition, the estimated frequency of serious adverse events demonstrates that regional blocks in children under general anaesthesia are no less safe than in awake adults. In infants, the techniques of direct thoracic epidural placement or caudal placement with cephalad threading each have distinct advantages and disadvantages. As the data cannot support the safety of one technique over the other, the site of epidural insertion remains largely a matter of anaesthetist discretion.     

Coloured chlorhexidine cotton pads may help to identify cerebrospinal fluid during epidural or spinal anaesthesia

BACKGROUND: During complicated technical conditions in epidural or spinal anaesthesia, it may be difficult to safely identify the epidural space. The confirmation or exclusion of the presence of cerebrospinal fluid (CSF) during the procedure of regional anaesthesia is helpful to determine the position of the epidural needle in order to proceed with the anaesthetic block. METHODS: We have examined how CSF and different anaesthetic solutions change the colour of yellowish phenol red absorbed in cotton pads. RESULTS: Sodium chloride and local anaesthetic agents do not change the colour of yellowish phenol red. However, CSF immediately changes the colour from yellow to pink or red. Letting a drop of fluid from the epidural/spinal needle fall on to the cleaning pads filled with phenol red will enable the anaesthesiologist to immediately confirm the presence or absence of CSF. The higher pH of CSF relative to that of sodium chloride and local anaesthetic agents explains the different colour reaction. CONCLUSION: This colour reaction quickly identifies the presence of CSF and thus the intradural space during the procedure of spinal or epidural anaesthesia.     

Neuraxial anaesthesia in paediatrics

Neuraxial anaesthesia is a valuable tool in the practice of paediatric anaesthesia. Spinal and epidural blockade are used for a variety of surgical cases as the sole anaesthetic or as an adjunct to general anaesthesia, and confer significant postoperative analgesia. Caudal epidural anaesthesia is used extensively for lower abdominal, urological, and orthopaedic procedures in the setting of outpatient surgery. Lumbar and thoracic epidural infusions via a catheter can provide analgesia for chest and upper abdominal procedures. The potential complications associated with neuraxial anaesthesia can be minimized by prudent technique and careful management. The use of the ultrasound for real-time visualization during paediatric neuraxial blocks may improve safety, success rate, and pain control after surgery.     

Neuraxial anaesthesia in paediatrics

Neuraxial anaesthesia is a valuable aid in the practice of paediatric anaesthesia. Spinal and epidural blockade are used as either the sole anaesthetic or as an adjunct to general anaesthesia, and often confer significant postoperative analgesia. Caudal epidural anaesthesia is used extensively for lower abdominal, urological and orthopaedic procedures in the setting of outpatient surgery. Lumbar and thoracic epidural infusions via a catheter can provide analgesia for chest and upper abdominal procedures. Major complications related to neuraxial catheter placement are uncommon in paediatric anaesthesia, even though block placement is typically after the patient is anesthetized. The use of the ultrasound for real-time visualization during paediatric neuraxial blocks provides an opportunity for observing final catheter position or confirming successful injection into the epidural space.     

Change in anaesthetic practice for Caesarean section in Germany

BACKGROUND: Initial data from 1996 revealed that in contrast to several other countries general anaesthesia was the preferred anaesthetic technique for Caesarean section in Germany. However, anaesthetic practice for Caesarean section has changed during the last decades world-wide. This investigation was performed to obtain more actual data on anaesthetic procedures in obstetric patients in German hospitals. METHODS: Questionnaires on the practice of anaesthesia for Caesarean section were mailed to 918 German departments of anaesthesiology. Furthermore, the survey evaluated severe perioperative complications in obstetric patients. RESULTS: The 397 completed replies in this survey represent 41.3% of all German deliveries in 2002. Spinal anaesthesia is now the most common technique (50.5%) for elective Caesarean section. In case of urgent and emergency Caesarean, delivery figures decrease to 34.6% and 4.8%, respectively. Epidural anaesthesia is performed in 21.6% of scheduled and 13.2% and 1.0% of non-scheduled urgent or emergency Caesarean sections, respectively. Four maternal deaths and several non-fatal episodes of gastric content aspiration were reported by the respondents. CONCLUSIONS: Compared to data obtained 6 years ago a significant increase in regional anaesthesia for Caesarean section has developed, with spinal anaesthesia being the preferred technique. Surveys can help to initiate discussion and improve current practice of anaesthetic care.     

The principles and conduct of anaesthesia

Anaesthesia is one of the younger specialties of medicine and has made immense advancement since its inception. The development of modern anaesthesia techniques, drugs, and monitoring methods has facilitated the development and advancement of surgical practice, which benefits patients. In this article, we provide an overview of the pharmacology and the conduct of a general anaesthetic. Regional anaesthesia has always been an integral part of the practice of anaesthesia and surgery. We discuss the essential components of the practice of neuraxial anaesthesia and peripheral nerve blocks. It is known that many surgical trainees are deficient in the knowledge of safe administration of local anaesthetics which we have tried to address in this article.     

The principles and conduct of anaesthesia

Anaesthesia is one of the younger specialties of medicine and has made immense advancement since its inception. The development of modern anaesthesia techniques, drugs, and monitoring methods has facilitated the development and advancement of surgical practice, which benefits patients. In this article, we provide an overview of the pharmacology and the conduct of a general anaesthetic. Regional anaesthesia has always been an integral part of the practice of anaesthesia and surgery. We discuss the essential components of the practice of neuraxial anaesthesia and peripheral nerve blocks. It is known that many surgical trainees are deficient in the knowledge of safe administration of local anaesthetics, which we have tried to address in this article.     

Neuraxial anaesthesia in paediatrics

Neuraxial anaesthesia is a valuable aid in the practice of paediatric anaesthesia. Spinal and epidural blockade are used as either the sole anaesthetic or as an adjunct to general anaesthesia, and often confer significant postoperative analgesia. Caudal epidural anaesthesia is used extensively for lower abdominal, urological and orthopaedic procedures in the setting of outpatient surgery. Lumbar and thoracic epidural infusions via a catheter can provide analgesia for chest and upper abdominal procedures. Thoracic paravertebral blocks provide analgesia equivalent to thoracic epidurals but with fewer side effects. Their use in thoracic surgery have helped reduce the incidence of chronic thoracotomy pain. Major complications related to neuraxial catheter placement are uncommon in paediatric anaesthesia, even though block placement is typically after the patient is anaesthetized to ensure immobility during puncture. Available evidence suggest that it is safe to place regional blocks in children during general anaesthesia. Ultrasound is an excellent imaging modality for identifying the dura mater as the dura appears highly echogenic on ultrasound scans. Ultrasound imaging help estimate the location and level of spinous interspaces and may be useful in children with obesity, prior surgical instrumentation or scoliosis. The use of the ultrasound for real-time visualization during paediatric neuraxial blocks provides an opportunity for observing final catheter position or confirming successful injection into the epidural space.     

A survey of antenatal and peripartum provision of information on analgesia and anaesthesia

Pregnant women should receive information about what they might expect to experience during their delivery. Despite this, research shows many women are inadequately prepared for anaesthetic interventions during labour. We surveyed 903 postnatal women across 28 Greater London hospitals about: the analgesic and anaesthetic information that they recalled receiving during pregnancy and delivery; their confidence to make decisions on analgesia; and their satisfaction with the analgesia used. Wide variation was observed between hospitals. Overall, 67 of 749 (9.0%) women recalled receiving antenatal information covering all aspects of labour analgesia, and 108 of 889 (12.1%) covering anaesthesia for caesarean section. Regarding intrapartum information, 256 of 415 (61.7%) respondents recalled receiving thorough information before epidural insertion for labour analgesia, and 102 of 370 (27.6%) before anaesthesia for caesarean section. We found that 620 of 903 (68.7%) women felt well enough informed to be confident in their analgesic choices, and 675 of 903 (74.8%) stated that their analgesia was as expected or better. Receiving information verbally, regardless of provider, was the factor most strongly associated with respondents recalling receiving full information: odds ratio (95%CI) for labour analgesia 20.66 (8.98–47.53; p < 0.0001); epidural top-up for caesarean section 5.93 (1.57–22.35; p = 0.01); and general anaesthesia for caesarean section 12.39 (2.18–70.42; p = 0.01). A large proportion of respondents did not recall being fully informed before an anaesthetic intervention. Collaboration with current antenatal service providers, both in promoting information delivery and providing resources to assist with delivery, could improve the quality of information offered and women's retention of that information.     

Characteristics of children less than 2 years of age undergoing anaesthesia in Denmark 2005–2015: a national observational study

There are few data available that describe the current anaesthetic management of children. We have analysed anaesthetic practice and peri‐operative complications for children in Denmark aged less than two years. We conducted a population‐based observational cohort study using the Danish Anaesthesia Database to identify children who received anaesthesia in hospital from 1 January 2005 until 31 December 2015. Data were combined with that from the Danish National Patient Registry and the Danish Civil Registration System. Age, sex, height, weight, ASA physical status, days in hospital before anaesthesia, number of anaesthetics per child, indications for anaesthesia, methods of anaesthesia, airway management and complications were all recorded. A total of 17,436 children (64% of whom were male) received 27,653 anaesthetics during the study period. In 58% of cases, the child had an ASA physical status score of 1. Thirty‐seven percent had a previous anaesthetic episode. Seventy‐nine percent were anaesthetised at a university hospital. The indications for anaesthesia were surgery (70%), diagnostic radiology (16%), non‐surgical care (11%) and other indications (3%). General anaesthesia combining intravenous and inhalational agents was the most common approach for surgery (68%) and diagnostic radiology (47%). For non‐surgical care, general anaesthesia using inhalational agents was the most common method (42%). Neuraxial blocks were used infrequently. The most common regional anaesthetic nerve block was an infraclavicular brachial plexus block (11%). Peri‐operative complications occurred in 1.71% of cases. A large proportion of anaesthetics were conducted in children with comorbidities. Non‐surgical indications for anaesthesia were frequent and peri‐operative complications were rare.     

Does regional anaesthesia improve outcome after surgery?

There is conclusive evidence that regional anaesthesia provides better postoperative analgesia than systemic opioid techniques. Regional anaesthesia also has the potential to improve the functional outcome from surgery, although proving this in a clinically relevant way is challenging; many studies are inconclusive with methodological weaknesses making comparison difficult and offering conflicting evidence. Systematic reviews offer better evidence that regional anaesthesia improves outcome but both anaesthetic and surgical practice have evolved over time, so older data may not be relevant to current practice. Regional anaesthesia improves outcome only when incorporated into a structured postoperative rehabilitation and recovery programme (Enhanced Recovery), using the effective analgesia provided to achieve specific targets. These targets include early mobilization, active physiotherapy and early return to enteral nutrition. Other benefits of regional anaesthesia (reduced blood loss, lower risk of thromboembolic events and duration of ileus) also contribute to a reduction in postoperative morbidity. However, unless the postoperative recovery programme is modified to incorporate these benefits into a patient's recovery, the full impact of regional anaesthesia on surgical outcome will not be realized.     

The use of processed electroencephalography (pEEG) in obstetric anaesthesia: a narrative review

Accidental awareness under general anaesthesia (AAGA) remains a major complication of anaesthesia. The incidence of AAGA during obstetric anaesthesia is high relative to other specialities. The use of processed electroencephalography (pEEG) in the form of “depth of anaesthesia” monitoring has been shown to reduce the incidence of AAGA in the non-obstetric population.The evidence for using pEEG to prevent AAGA in the obstetric population is poor and requires further exploration. Furthermore, pregnancy and disease states affecting the central nervous system, such as pre-eclampsia, may alter the interpretation of pEEG waveforms although this has not been fully characterised.National guidelines exist for pEEG monitoring with total intravenous anaesthesia and for “high-risk” cases regardless of technique, including the obstetric population. However, none of the currently available guidelines relates specifically to obstetric anaesthesia.Using pEEG monitoring for obstetric anaesthesia may also provide additional benefits beyond a reduction in risk of AAGA. These potential benefits include reduced postoperative nausea and vomiting, reduced anaesthetic agent use, and a shorter post-anaesthetic recovery stay. In addition, pEEG acts as a surrogate marker of cerebral perfusion, and thus as an additional monitor for impending cardiovascular collapse, as seen in amniotic fluid embolism.The subtle physiological and pathological changes in EEG activity that may occur during pregnancy are an unexplored research area in the context of anaesthetic pEEG monitors. We believe that the direction of clinical practice is moving towards greater use of pEEG monitoring and individualisation of anaesthesia.