Anaesthesia for endovascular aneurysm repair

The surgical management of an abdominal aortic aneurysm (AAA) can be undertaken via an open or endovascular approach. The use of an endovascular approach has benefits for the patient by being less invasive with initially lower mortality and morbidity and a shorter hospital stay, although the long-term outcomes match open techniques. The endovascular technique requires more specialist resources, including stents and imaging equipment. In the UK, endovascular techniques are usually performed in specialist hospitals with specialist teams of interventional radiologists, vascular surgeons and anaesthetists. Patients requiring endovascular repair of their AAA can present the anaesthetist with a range of complex comorbidities that require specific management and optimization preoperatively. The intraoperative management of the patient can vary, depending on patient, surgical and anaesthetic factors and from local, regional or general anaesthesia techniques. The postoperative complications are generally minimal, but patients require lifelong follow up making the procedure more expensive than an open operation.     

Local anaesthesia for dacryocystorhinostomy

Dacryocystorhinostomy is a surgical procedure for correction of chronic tearing. While it has been performed most frequently on inpatients under general anaesthesia in the past, it can be performed very well as an outpatient procedure under regional anaesthesia, using minimal amounts of sedation. Although some practitioners have used a variety of local infiltration methods in the past, thorough knowledge of the anatomy of the innervation of the operative field allows the anaesthetist to block specific areas in order to achieve maximal effects. The method of regional anaesthesia described provides solid anaesthesia and excellent intranasal haemostasis for the operation. This technique employs an infra-orbital nerve block, medial canthal peribulbar block, lacrimal canal infiltration, infiltration of the lateral nasal wall and intranasal packing with anaesthetic-soaked sponges, in order to ensure complete anaesthesia. The technique is easy to master and can be performed rapidly once learned. The author also discusses sedation techniques that can be used to allow anaesthetic injections to be performed with minimal discomfort to the patient.     

Anaesthesia for endovascular aneurysm repair

A patient with an abdominal aortic aneurysm can have surgical management through either an open or endovascular approach. The use of an endovascular approach has benefits for the patient by being a less invasive approach with initially lower mortality and morbidity and lower lengths of hospital stay, although longer term outcomes match open techniques. The endovascular technique requires more specialist equipment, including stents and imaging equipment. In the UK they are usually performed in specialist hospitals with teams of interventional radiologists, vascular surgeons and anaesthetists working together. Patients presenting for endovascular repair of their abdominal aortic aneurysm can present the anaesthetist with range of complex comorbidities which require specific management and optimization pre-operatively. The intraoperative management of the patient can vary, depending on patient, surgical and anaesthetic factors, from local anaesthetic, regional techniques or general anaesthesia. The postoperative complications are generally minimal, but the patients require lifelong follow up, making the procedure more expensive than an open procedure.     

Systems Theory and the Anaesthetist

The application of the various aspects of systems theory has increased steadily over the last 10 years and has proved useful in such diverse fields as surgical services (Spratt et al. 1974), public health (Haas 1974), education (Harrington 1966), nephrology (Bigelow et al. 1973), medical information (Davis 1973), behavior (Shooster 1974), internal medicine (Guyton et al. 1972), metaphysics (Gayer 1972), and sociology (Attinger & Millendorfer 1968). More recently, rystems analysis has been applied to anaesthetic systems in the engineering literature (Smith & Schwede: 1972) and has begun to appear in the anaesthesia literature (Brows 1973). The anaesthetist in the operating room is part of a complex system. In its simplest form the latter involves the anaesthetist, the anaesthesia delivery system, the patient and the surgeon. This discussion is intended to introduce the anaesthetist to some of the terminology and techniques common to the systems analysis approach. Examples have been drawn from biological aystems in man which have proved useful to describe in feedback control terms. Where possible, the examples used are those most relevant to anaesthesiology.     

Pre-operative assessment of cardiac patients for non-cardiac surgery

Non-cardiac surgery presents significant risks to patients with cardiac diseases. With the improvement in anaesthetic techniques and intensive care facilities, many cardiac patients who in the past would have been considered as being at too great a risk are now being considered for non-cardiac surgery. Smaller centres must still practise strict selection of patients if they do not possess an intensive care unit with facilities for full haemodynamic monitoring. We present a review of the recent literature and current practice at our hospital to assist clinicians in assessing these patients for anaesthesia. However, the final decision whether the patient is fit for anaesthesia still rests with the anaesthetist.     

Epidural anesthesia

In epidural anaesthesia, the anaesthetist injects one or more drugs into the epidural space bordering on the spinal dura mater to achieve a "central" and/or "neuraxial" block. It is one of the earliest techniques in anaesthesia, originally performed exclusively with local anaesthetic agents. Adding other drugs and combining epidural with general anaesthesia or adapting the technique to the needs of children has extended the list of indications. Continuous epidural analgesia is an important tool in postoperative pain management. More and more often, the increasing proportion of patients who have comorbidities or are permanently taking medication that modulates the clotting system demands that the anaesthesiologist balance the individual risks and benefits before inducing epidural anaesthesia.     

Periduralanästhesie

In epidural anaesthesia, the anaesthetist injects one or more drugs into the epidural space bordering on the spinal dura mater to achieve a “central” and/or “neuraxial” block. It is one of the earliest techniques in anaesthesia, originally performed exclusively with local anaesthetic agents. Adding other drugs and combining epidural with general anaesthesia or adapting the technique to the needs of children has extended the list of indications. Continuous epidural analgesia is an important tool in postoperative pain management. More and more often, the increasing proportion of patients who have comorbidities or are permanently taking medication that modulates the clotting system demands that the anaesthesiologist balance the individual risks and benefits before inducing epidural anaesthesia.     

Circumcision of neonates and children without appropriate anaesthesia is unacceptable practice

Circumcision is painful surgery and appropriate intraoperative anaesthesia and postoperative analgesia is required. This is recognised in the policies of the Royal Australasian College of Physicians and the majority of Australian State Health Departments. Nevertheless, anecdotal evidence exists that neonatal circumcision continues to be performed in Australia with either no anaesthesia or with inadequate anaesthesia. This paper presents the evidence that neonatal circumcision is painful and reviews the available anaesthetic techniques. The authors conclude that general anaesthesia is arguably the most reliable way of ensuring adequate anaesthesia, although this may mean deferment of the procedure until the child is older. Local or regional anaesthesia for neonatal circumcision ideally requires a separate skilled anaesthetist (other than the proceduralist) to monitor the patient and intervene if the anaesthesia is inadequate. Topical anaesthesia with lignocaine-prilocaine cream is insufficient.     

Anaesthesia for neuroimaging and neurointerventional radiology

Neuroradiology is an expanding field and likely to involve increasing input from the anaesthetist. Many patients need careful anaesthesia and preoperative care during procedures carried out in sites remote from the normal operating theatre or ICU. As the number and complexity of imaging techniques increases it becomes difficult for the anaesthetist to be aware of all the potential hazards involved. In this article the basic principles of imaging techniques and interventional procedures are discussed with reference to safety, monitoring and anaesthesia. The concerns regarding exposure to ionizing radiation and safety within powerful magnetic fields during magnetic resonance imaging and spectroscopy are discussed. The standard of care in terms of conducting anaesthesia and monitoring patients during imaging and interventional procedures in remote and hostile environments is presented.     

Paediatric cardiac catheterization: innovations

In recent years interventional procedures have been introduced to the field of paediatric cardiac catheterization. These procedures continue to develop in complexity and increasingly are being applied to patients with reduced cardiovascular reserve, as an alternative to cardiac surgery or when cardiac surgery with cardiopulmonary bypass is contraindicated. More frequently anaesthetists are being called upon to provide support in sedating, anaesthetizing or/and resuscitating these patients. The purpose of this review is to give a comprehensive update of the interventional procedures and to review the anaesthetic management techniques as they apply to the catheterization laboratory. We will discuss possible complications and management strategies from our own experience and the experience of others. We have observed that as more complicated procedures are performed the anaesthetist plays a pivotal role in the management of the patient from arrival to departure from the cardiac catheterization laboratory, and in preventing mortality and major morbidity. Although the economic consequences of interventional cardiological techniques remain unclear, the field continues to expand and more complex procedures are continually being introduced.     

Anaesthesia for endoscopic surgery

Anaesthesia for endoscopic airway surgery involves unique challenges. The anaesthetist and surgeon are working in close anatomical proximity and the concept of shared airway is never more relevant. Understanding the planned procedure and the needs of the surgeon for access to the surgical field will enable the provision of anaesthesia and airway management using a variety of techniques. Planning for safe induction, maintenance and emergence of anaesthesia will also be guided by the specific pathology and patient characteristics and requires effective communication between the surgeon and anaesthetist.     

Anaesthesia for endoscopic surgery

Anaesthesia for endoscopic ear, nose and throat surgery involves unique challenges. The anaesthetist and surgeon must work in close anatomical proximity, and the concept of the ‘shared airway’ is never more relevant. The anaesthetist requires a thorough understanding of the planned procedure and the specific requirements of the surgery in order to maximize accessibility to the surgical field whilst also providing safe airway management and maintenance of anaesthesia using a variety of specialist techniques. Planning for safe induction, maintenance and emergence from anaesthesia is guided by the underlying pathology and individual patient characteristics, and requires effective communication between the multidisciplinary team.     

Anaesthesia for endoscopic surgery

Anaesthesia for endoscopic airway surgery involves unique challenges. The anaesthetist and surgeon are working in close anatomical proximity and the concept of shared airway is never more relevant. Understanding the planned procedure and the needs of the surgeon for access to the surgical field will enable the provision of anaesthesia and airway management using a variety of techniques. Planning for safe induction, maintenance and emergence of anaesthesia will also be guided by the specific pathology and patient characteristics and requires effective communication between the surgeon and anaesthetist.     

From Clover to computer

The control of depth of anaesthesia has been viewed as a control-system problem the solution of which can involve both feedback and feedforward techniques. The nature of the problem in Clover's day and the solutions he found have been examined. A similar analysis has been made in respect of the modern anaesthetist. Finally, the way in which computers may aid the anaesthetist in his task has been illustrated by reference to various attempts reported from around the world and, in particular, by describing the development in Cardiff of a system which should produce, in the brain of the patient, any tension of an inhaled anaesthetic which the anaesthetist chooses to specify.     

Anaesthesia for interventional vascular radiology

Interventional vascular radiology is a rapidly expanding field, but can broadly be split into embolization and stent-grafting techniques. Frequently these can be performed percutaneously with local anaesthetic infiltration and do not require the involvement of an anaesthetist. Some procedures, particularly endovascular aneurysm repair (EVAR) require surgical access to the vasculature, necessitating anaesthesia. Solid organ embolization can be painful and patients for haemorrhage control may also require our input to manage ongoing resuscitation and stabilization. Each procedure is different and communication and team working is essential to understand the planned procedure and the requirements for anaesthesia and operating conditions.This article will discuss the different procedures performed (excluding neurological and cardiological interventions) with a focus on EVAR, and the anaesthetic implications of them.     

Anaesthesia for living-donor renal transplant

Living-donor nephrectomy is a relatively new surgical procedure. Unlike most other surgical procedures it exposes a healthy subject to the risks of a major surgical procedure entirely for the benefit of another individual. The main task for the anaesthetist is to provide safe anaesthesia for the donor, and ensure optimal conditions for both the donated and the remaining kidney. Several surgical techniques exist, and their impacts with respect to anaesthesia are discussed.     

Sedation for vitreoretinal surgery: a comparison of anaesthetist-administered midazolam and patient-controlled sedation with propofol

Local anaesthesia is increasingly being used for vitreoretinal surgery, but the optimal technique for sedation remains unclear. Anaesthetist-administered midazolam, which is often used, was compared in this study to patient-controlled sedation with propofol in 43 patients undergoing 50 vitreoretinal procedures. A variety of patient, anaesthetist and surgical endpoints were measured. There were no significant outcome differences between the two agents except that midazolam produced more amnesia for the local anaesthetic eye block. However, several outcomes and the observations in patients who experienced both agents showed a trend in favour of propofol for intraoperative sedation. We conclude that both approaches are safe and that patient-controlled sedation with propofol is at least as satisfactory as anaesthetist-administered midazolam.     

Anaesthesia and minimally invasive surgery

Minimally invasive surgery is commonly performed because of various advantages such as reduced postoperative pain, faster recovery, and reduced postoperative pulmonary complications. However, anaesthesia for laparoscopy can be difficult and potentially hazardous in long, complex surgical procedures and in sick patients. Establishment of CO₂ pneumoperitoneum produces adverse pathophysiological changes due to increased intra-abdominal pressure and hypercapnia, and these are further altered by postural changes. Laparoscopy is also associated with potential complications such as extraperitoneal gas insufflation and pneumothorax. It is important for the anaesthetist to understand the advantages and potential risks. General anaesthesia with endotracheal intubation is the most common anaesthetic technique, but supraglottic airway devices can sometimes be used. Neuroaxial anaesthesia has been used in some laparoscopic procedures as the sole anaesthetic technique. This article will focus on the pathophysiological changes caused by CO₂ pneumoperitoneum, the anaesthetic management for patients undergoing laparoscopy, and potential complications.     

Ultrasonographic control of the puncture level for lumbar neuraxial block in obstetric anaesthesia

BACKGROUND: Errors in the judgement of puncture level during neuraxial anaesthesia can lead to significant complications. The aim of this study was to assess, in obstetric anaesthesia, the accuracy of clinical determination of the lumbar spinal interspace level, using surface ultrasound imaging as control. METHODS: At the anaesthesia follow-up visit, women who had received lumbar neuraxial anaesthesia during labour were prospectively included. The intervertebral level of needle insertion, located by the needle scar position, was identified by ultrasonography and compared with the clinical level reported on the chart by the anaesthetist who performed the block. RESULTS: Ninety-nine women were studied. The clinical puncture level was accurate in 36.4% of patients. Ultrasound examination showed the puncture level to be more cephalad than the level noted in the anaesthetic record in almost 50% of patients. In 15% of patients, the puncture level was more caudad than the anaesthetist had assessed. Factors including type of anaesthesia, indication, time period, level of anaesthetic experience, BMI, and spinal pathology did not seem to influence the frequency of errors. CONCLUSIONS: The observed differences between clinical and ultrasonic identification of spinal puncture level highlight the potential for serious complications associated with the performance of neuraxial blocks above the spinous process of L3 in the parturient. With the increase in popularity of techniques involving puncture of the dura mater for labour anaesthesia, we feel that awareness of this risk is important.     

Anaesthesia for spinal surgery

Patients with and without spinal disease are at risk of neurological damage during anaesthesia, even when the surgery is not directed at the spine. Certain types of spinal surgery carry a substantial risk. Reports of spinal cord damage due to direct laryngoscopy are unconvincing. Evoked potential spinal cord monitoring is used increasingly during anaesthesia, and successful recording of potentials requires the co-operation of the anaesthetist. Airway problems are common in cervical spine disease, particularly if the disease affects the upper three vertebrae. Anterior surgical approaches to the craniocervical junction involve extensive surgery, with implications for airway management and nutrition.