Obstructive sleep apnoea and anaesthesia

Obstructive sleep apnoea (OSA) is the most prevalent sleep disorder, affecting up to 5% of the population. It can have a considerable impact upon perioperative morbidity and mortality. Patients require thorough preoperative assessment including a detailed history, the use of scoring systems to assess severity (such as the STOP-Bang questionnaire and the B-APNEIC score) and physical examination, with particular attention to airway assessment. Elective surgical patients who are deemed to be of high risk for OSA should be referred for polysomnography and implementation of continuous positive airway pressure therapy prior to surgery if indicated. Those patients deemed to be of low risk may be suitable for day surgery. Intraoperative anaesthesia management may include regional anaesthesia, local anaesthetic infiltration, or general anaesthesia depending on both patient and surgical factors. Particular attention should be paid to the potential for difficult airway management and avoidance of sedative agents and opioids where possible. Patients with OSA have an increased risk of cardiovascular and respiratory postoperative complications. Postoperative management should be guided by the severity of OSA, the occurrence of adverse respiratory events in the post anaesthesia care unit and the requirement for opioid analgesia.     

Principles of anaesthesia in urological surgery

Anaesthesia for urological surgery poses particular challenges for the anaesthetist related to the patient population and procedure type. The aim of this article is to cover the general principles of anaesthesia, with dedicated sections relevant to practising urological surgeons. This represents vast amounts of knowledge that cannot be covered in one article. We will focus upon preoperative preparation for surgery and anaesthesia, perioperative management including monitoring and analgesia, and postoperative management including fluid balance, critical care and recovery. Significant proportions of urological surgical patients have some degree of renal failure and this may be related to the surgery required. Anaesthetic care of patients with chronic renal impairment and transplant surgery will be covered in a future review.     

Regional anaesthesia with sedation protocol to safely debride sacral pressure ulcers

A treatment challenge for patients with sacral pressure ulcers is balancing the need for adequate surgical debridement with appropriate anaesthesia management. We are functioning under the hypothesis that regional anaesthesia has advantages over general anaesthesia. We describe our regional anaesthesia protocol for perioperative and postoperative management.     

General anaesthesia in end-of-life care: extending the indications for anaesthesia beyond surgery

In this article, we describe an extension of general anaesthesia – beyond facilitating surgery – to the relief of suffering during dying. Some refractory symptoms at the end of life (pain, delirium, distress, dyspnoea) might be managed by analgesia, but in high doses, adverse effects (e.g. respiratory depression) can hasten death. Sedation may be needed for agitation or distress and can be administered as continuous deep sedation (also referred to as terminal or palliative sedation) generally using benzodiazepines. However, for some patients these interventions are not enough, and others may express a clear desire to be completely unconscious as they die. We summarise the historical background of an established practice that we refer to as ‘general anaesthesia in end-of-life care’. We discuss its contexts and some ethical and legal issues that it raises, arguing that these are largely similar issues to those already raised by continuous deep sedation. To be a valid option, general anaesthesia in end-of-life care will require a clear multidisciplinary framework and consensus practice guidelines. We see these as an impending development for which the specialty should prepare. General anaesthesia in end-of-life care raises an important debate about the possible role of anaesthesia in the relief of suffering beyond the context of surgical/diagnostic interventions.     

McArdle's disease and anaesthesia: case reports. Review of potential problems and association with malignant hyperthermia

BACKGROUND: McArdle's disease of isolated deficiency in glycogen degradation in skeletal muscles has the potential of creating perioperative anaesthesiological problems; such as hypoglycaemia, rhabdomyolysis, myoglobinuria, acute renal failure and possibly malignant hyperthermia. METHODS: Eight patients with McArdle's disease were asked about previous surgery, anaesthesia and perioperative problems, and available hospital records were reviewed. Existing literature was reviewed for reports on McArdle's disease and anaesthesia. RESULTS: The eight patients had 35 anaesthesias (23 general anaesthesias, three regional anaesthesias and nine local anaesthesias). Perioperative problems of a non-specific nature were mentioned in three cases of general anaesthesia: two with postoperative nausea/vomiting, and one with an episode of tachycardia and low blood pressure. Three patients were tested for malignant hyperthermia (MH) using the in vitro contracture test (IVCT); two of them with a positive result. The literature search revealed seven case reports of McArdle's disease and anaesthesia. Apart from one report of hyperthermia, pulmonary oedema and rhabdomyolysis; probably not associated with MH, no problems were encountered from the literature search. CONCLUSION: McArdle's disease does not seem to cause severe perioperative problems in routine anaesthetic care. However, measures for preventing muscle ischaemia and rhabdomyolysis should be kept in mind, as well as the potential for these patients to develop postoperative fatigue, myoglobinuria and renal failure. Although no clinical association with malignant hyperthermia has been established, many of these patients can have a positive in vitro contracture test, and simple prophylactic measures, as with malignant hyperthermia, may be recommended if otherwise not contraindicated.     

Perioperative management of infant inguinal hernia surgery; a review of the recent literature

Inguinal hernia surgery is one of the most common electively performed surgeries in infants. The common nature of inguinal hernia combined with the high-risk population involving a predominance of preterm infants makes this a particular area of interest for those concerned with their perioperative care. Despite a large volume of literature in the area of infant inguinal hernia surgery, there remains much debate amongst anesthetists, surgeons and neonatologists regarding the optimal perioperative management of these patients. The questions asked by clinicians include; when should the surgery occur, how should the surgery be performed (open or laparoscopic), how should the anesthesia be conducted, including regional versus general anesthesia and airway devices used, and what impact does anesthesia choice have on the developing brain? There is a paucity of evidence in the literature on the concerns, priorities or goals of the parents or caregivers but clearly their opinions do and should matter. In this article we review the current clinical surgical and anesthesia practice and evidence for infants undergoing inguinal hernia surgery to help clinicians answer these questions.     

Regional anaesthesia for orthopaedic procedures

Regional anaesthetic techniques are fundamental in the anaesthetic care of orthopaedic patients. They may be used as the primary anaesthetic technique or to provide postoperative pain relief. Compared to general anaesthesia alone, regional techniques can provide superior perioperative analgesia, fewer systemic drug adverse effects such as nausea, vomiting and confusion, and earlier mobilization which can reduce nosocomial complications and facilitate expedited hospital discharge. Disadvantages include block failure, nerve injury, unrecognised injury to the anaesthetised limb, prolonged motor blockade and local anaesthetic toxicity. Preoperative assessment should identify contraindications, document pre-existing neurological deficits, and clarify surgical and perioperative aims. Informed consent should be obtained after a clear explanation of the procedure, its risks, and potential complications. Serious and long-term neurological complications are rare and may be reduced by an awake regional technique, sonographic guidance, regular aspiration and by ensuring low pressure injections. Postoperative follow-up is essential and suspicious neurological findings should be detected, investigated, and managed in an early and timely manner.     

Shorter discharge time after regional or intravenous anaesthesia in combination with laryngeal mask airway compared with balanced anaesthesia with endotracheal intubation

BACKGROUND AND OBJECTIVE: The efficiency of operating room times can be significantly improved using rapid changes between operative procedures. We performed a retrospective analysis using electronic anaesthesia charts that compared anaesthesia-related times between the three most frequently performed types of anaesthesia (for orthopaedic surgery) to evaluate the potential for a quicker turn-around between cases. METHODS: A total of 5614 anaesthetic procedures in trauma-related orthopaedic surgery were performed from 1997 to 1999. All were documented with an automatic record-keeping system. Data were compared for intravenous anaesthesia with the laryngeal mask airway, balanced anaesthesia with tracheal intubation and regional anaesthesia. The primary outcome measure was the time needed for emergence from anaesthesia after the end of surgery. Statistical evaluation was performed with matched triples for all three types of anaesthesia (155 triples for ambulatory surgery, 249 triples for in-patient care). RESULTS: For ambulatory surgery, the induction time was significantly shorter for general anaesthesia (23.7 min for intravenous anaesthesia, 22.7 min for balanced anaesthesia techniques) compared with regional anaesthesia (27.2 min). The time from the end of the surgical procedure to transfer of the patient out of the operating room was shortest for regional anaesthesia (6.3 min) compared with intravenous anaesthesia (9.0 min) and balanced anaesthesia (12.5 min) techniques. Results were comparable for in-patients: regional anaesthesia required significantly longer for its induction, but less time for patient discharge from the operating room. CONCLUSIONS: The use of a regional anaesthesia technique or one involving intravenous anaesthesia in combination with the laryngeal mask airway may lead to a reduction in discharge time compared with a balanced anaesthesia technique with endotracheal intubation. Thus, improved use of resources may be achieved.     

General anaesthesia for ophthalmic surgery

The majority of ophthalmic surgeries are performed as day cases under topical or regional anaesthesia with or without intravenous sedation. However, general anaesthesia is necessary in certain circumstances e.g. local anaesthetic allergy or patients who are unable to cooperate or to lie flat or still. Patients for ophthalmic surgery are frequently elderly with multiple comorbidities, such as diabetes and hypertension. Patients with rare genetic syndromes may present for eye surgery. Therefore adequate preoperative evaluation and preparation will minimize perioperative complications. The goals of general anaesthesia are smooth induction and emergence, with stable intra-ocular pressure (IOP) and akinesia of the globe. These can be achieved with a combination of intravenous and inhalational agents with or without muscle relaxants and opiates. Use of the laryngeal mask airway has the advantage of causing a smaller rise in IOP on insertion and less coughing on emergence. Total intravenous anaesthesia with propofol and remifentanil has the advantages of causing less postoperative nausea and vomiting (PONV), reduced stress response to airway intervention, rapid recovery and smooth emergence. Some eye procedures require special consideration, for example, strabismus and vitreoretinal surgery involves traction of the rectus muscles producing a higher incidence of oculocardiac reflex and PONV. Most ophthalmic surgery produces mild to moderate pain amenable to non-opioid analgesics. Intraoperative topical and regional anaesthesia reduce postoperative pain and opiate requirement. Open globe injury and a full stomach present unique challenges to prevent increase in IOP as well as protecting the airway.     

General anaesthesia for ophthalmic surgery

The majority of ophthalmic surgeries are performed as day cases under topical or regional anaesthesia with or without intravenous sedation. However, general anaesthesia is necessary in certain circumstances e.g. local anaesthetic allergy or patients who are unable to cooperate or to lie flat or still. Patients for ophthalmic surgery are frequently elderly with multiple comorbidities, such as diabetes and hypertension. Patients with rare genetic syndromes may present for eye surgery. Therefore adequate preoperative evaluation and preparation will minimize perioperative complications. The goals of general anaesthesia are smooth induction and emergence, with stable intra-ocular pressure (IOP) and akinesia of the globe. These can be achieved with a combination of intravenous and inhalational agents with or without muscle relaxants and opiates. Use of the laryngeal mask airway has the advantage of causing a smaller rise in IOP on insertion and less coughing on emergence. Total intravenous anaesthesia with propofol and remifentanil has the advantages of causing less postoperative nausea and vomiting (PONV), reduced stress response to airway intervention, rapid recovery and smooth emergence. Some eye procedures require special consideration, for example, strabismus and vitreoretinal surgery involves traction of the rectus muscles producing a higher incidence of oculocardiac reflex and PONV. Most ophthalmic surgery produces mild to moderate pain amenable to non-opioid analgesics. Intraoperative topical and regional anaesthesia reduce postoperative pain and opiate requirement. Open globe injury and a full stomach present unique challenges to prevent increase in IOP as well as protecting the airway.     

Relaxing intraoperative natural sound blunts haemodynamic change at the emergence from propofol general anaesthesia and increases the acceptability of anaesthesia to the patient

BACKGROUND: It is known that auditory input, such as comforting music or sound, blunts the human response to surgical stress in conscious patients under regional anaesthesia. As auditory perception has been demonstrated to remain active under general anaesthesia, playing comforting sounds to patients under general anaesthesia might also modulate the response of these patients to surgical stress. METHODS: Fifty-nine patients scheduled for laparoscopic cholecystectomy were anaesthetized with propofol general anaesthesia in combination with epidural anaesthesia. Natural sounds, chosen preoperatively by each patient as being comforting, were played to 29 patients using headphones during surgery (S group) and the remainder of the patients (n = 30) were fitted with dummy open-type headphones (N group). We compared the haemodynamic change during anaesthesia and the acceptability of anaesthetic practice between the two groups in a randomized double-blind design. RESULTS: There were no differences in haemodynamics between the S and N groups during surgery. During the emergence from anaesthesia, the mean blood pressure and heart rate gradually increased; both parameters were significantly higher in the N group than in the S group. Postoperatively, patients in the S group perceived the experience of anaesthesia as significantly more acceptable than did those in the N group. CONCLUSION: These findings indicate that allowing patients comforting background sounds during general anaesthesia may blunt haemodynamic changes upon emergence from general anaesthesia and increase the acceptability of the experience of anaesthesia.     

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.     

Three episodes of gracilis free muscle transfer under epidural anaesthesia.

The use of regional anaesthesia in major surgery is associated with a lower risk of complications. However, recent evidence suggests that a vascular steal phenomenon may result in a reduction of free flap blood flow in such patients. We report three cases of free gracilis transfer under epidural anaesthesia in patients who were considered high risk for general anaesthesia. Our experience suggests that there remains an important role for epidural anaesthesia in the management of patients undergoing lower limb free flap reconstruction. The inability to undergo general anaesthesia does not preclude free flap surgery in carefully selected patients.     

General anaesthesia for dentistry

Although general anaesthesia is used to reduce the pain and anxiety associated with dental treatment, most dental procedures can be managed with good local anaesthesia, with or without conscious sedation. Since the 1960s there has been a progressive fall in the use of general anaesthesia for dentistry and in the mortality associated with it. However, between 1996 and 1999, eight people died as a result of dental anaesthesia, five of them were children. Investigations and inquiries into these deaths were critical of the standard of care provided in areas such as preoperative assessment, perioperative monitoring, resuscitation and transfer to a critical care facility. In response to these concerns, the General Dental Council (GDC), the Royal College of Anaesthetists (RCA) and the Department of Health (DOH) have issued closely linked guidelines for standards of care in dental general anaesthesia. Since 1 January 2002, general anaesthesia for dentistry has been confined to a hospital setting with critical care facilities. This article summarizes the guidelines, with particular reference to the status of the anaesthetist, the indications for general anaesthesia, patient referral and assessment, the definition of a hospital setting, peroperative monitoring and resuscitation, and management of the emergency; it also reviews the technique of dental anaesthesia in current use.     

Combined regional and general anaesthesia

Combining regional and general anaesthesia can have many advantages, particularly in patients undergoing major thoracic, abdominal or orthopaedic surgery. The use of regional anaesthetic techniques in anaesthetized children is an accepted standard of care, because needle and procedure phobias are very common and can result in severe anxiety, an inability to cooperate and sudden unpredictable movement. Epidural local anaesthetics have the potential of attenuating sympathetic hyperactivity, maintaining bowel peristalsis, sparing the use of opioids, and facilitating postoperative feeding and out-of-bed activity. Catheter techniques allow excellent and prolonged postoperative analgesia using epidural or peripheral nerve blocks. However, the superiority of regional techniques for hip fracture surgery and carotid endarterectomy has been disputed in several recent studies. As part of the combination technique, epidural block may in fact decrease blood flow in free flap surgery by a steal phenomenon, and increase intrapulmonary shunting during one-lung ventilation. The present review focuses on the use of a combination of regional and general anaesthesia for a variety of surgical procedures. It also compares the two anaesthetic techniques in elderly patients. The review is based on studies published during the past year.     

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.     

Epidural anaesthesia in ambulatory surgery

There is a growing demand for the performance of more surgical procedures on a day care basis. Regional anaesthetic techniques allow early and painless return of function after surgery. In 1991 and 1992 we used epidural anaesthesia for day care surgery in 180 patients and we reviewed the merits and problems involved with this regional technique.     

Blood glucose and insulin levels during epidural anaesthesia in children receiving dextrose-free solutions

Summary
This study was designed to evaluate the hyperglycaemic response to surgery in two groups of children undergoing minor surgical procedures and receiving dextrose-free solutions during the perioperative period. Twenty-four unpremedicated children of less than eight years of age were randomly assigned to receive either general anaesthesia using halothane, vecuronium and narcotics (GA group, n = 12) or general anaesthesia (halothane, vecuronium) combined with caudal anaesthesia (RA group, n = 12). In both groups blood glucose and insulin concentrations were measured during inhalational induction (T0), at the end of surgery (T1) and 30, 60, 120 min after surgery (T2, T3, T4). A significant hyperglycaemic response to surgery was observed in the GA group, while no changes in blood glucose were observed in the RA group. The maximal blood glucose value was observed 30 min after completion of surgery. Insulin changes followed closely changes in blood glucose values. This study demonstrates that epidural anaesthesia was effective in reducing the hyperglycaemic response to surgery in children scheduled for minor surgical procedures. The lack of increase in blood glucose values under epidural anaesthesia suggests that blood glucose levels should be monitored during the perioperative period, especially after a prolonged fasting time and when oral intake might be delayed.     

Regional anaesthesia in the obese patient: lost landmarks and evolving ultrasound guidance

Obesity is associated with a number of anaesthetic-related risks. Regional anaesthesia offers many potential advantages for the obese surgical patient. Advantages include a reduction in systemic opioid requirements and their associated side effects, and possible avoidance of general anaesthesia in select circumstances, with a lower rate of complications. Historically, performing regional anaesthesia procedures in the obese has presented challenges due to difficulty in identifying surface landmarks and availability of appropriate equipment. Ultrasound guidance may aid the regional anaesthesia practitioner with direct visualisation of underlying anatomic structures and real-time needle direction. Further research is needed to determine optimal regional anaesthesia techniques, local anaesthetic dosage and perioperative outcomes in obese patients.