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- Volume 14, Issue 1, 2008
Southern African Journal of Anaesthesia and Analgesia - Volume 14, Issue 1, 2008
Volumes & issues
Volume 14, Issue 1, 2008
Source: Southern African Journal of Anaesthesia and Analgesia 14 (2008)More Less
Author Christina LundgrenSource: Southern African Journal of Anaesthesia and Analgesia 14 (2008)More Less
This issue of the SAJAA celebrates the World Congress of Anaesthesiologists (WCA), and the first time that this event has been held on the African continent. It is indeed a privilege and very exciting to be able to publish many of the lecture texts from the 2008 SASA refresher course, which precedes the World Congress, being held here in Cape Town, South Africa.
Author A.I. LevinSource: Southern African Journal of Anaesthesia and Analgesia 14, pp 7 –12 (2008)More Less
"If ever there were a perfect marriage of drug with disease it might be between statins and atherosclerosis. At first the relationship was simple: statins inhibited synthesis of the cholesterol that contributed to atheroma, and less cholesterol meant less atheroma. Just as married couples often adapt to each other, so it is with statins and atheroma, or to be more precise, an increased understanding of their relationship has revealed an apparent adaptation."
Author J.W. SearSource: Southern African Journal of Anaesthesia and Analgesia 14, pp 14 –17 (2008)More Less
Diabetes mellitus (DM) is the most common non-communicable disease worldwide. Presently there are about 150 million diabetics; it affects between 1 and 2% of the population in the United Kingdom (UK), and about 10% of the population in the United States of America (USA). There may also be an equal number of undiagnosed patients. Diabetes affects about 1 in 6 patients over the age of 65 years, and 1 in 4 over the age of 85 years; over 90% of patients are non-insulin dependent (type 2) diabetics.
Author H. Van AkenSource: Southern African Journal of Anaesthesia and Analgesia 14, pp 19 –20 (2008)More Less
Thoracic - but not lumbar - epidural anaesthesia provides relevant clinical advantages compared with general anaesthesia, improving patients' morbidity and mortality after major surgical procedures. These advantages are excellent perioperative neuraxial analgesia and effective attenuation of the perioperative stress response by a reversible blockade of sympathetic afferents and efferents. In particular the attenuation of sympathetic tone prevents perioperative myocardial ischaemia and improves global and regional left ventricular function, pulmonary function and gastrointestinal perfusion. Thus, thoracic epidural anaesthesia is more than simply an anaesthetic regimen; it also has therapeutic options, especially in high-risk patients who underwent major cardiac, thoracic or abdominal surgical procedures.
Author J.H. CamposSource: Southern African Journal of Anaesthesia and Analgesia 14, pp 22 –26 (2008)More Less
Recent advances in surgical techniques for thoracic, cardiac, and oesophageal surgery have led to an increased use of lung separation techniques. Currently, double-lumen endotracheal tubes (DLT) and bronchial blockers (an Arndt wire-guided endobronchial blocker, a Cohen Flexitip endobronchial blocker, or the Fuji Uniblocker) are used. Achieving successful lung separation relies on knowledge of the anatomical distances of the airway, flexible fibreoptic bronchoscopy techniques, and familiarity with left and right-sided DLTs and bronchial blockers.
In general, lung isolation techniques are designed to: facilitate surgical exposure for cases involving the thoracic cavity, to prevent contamination of the contralateral lung in cases where pus or haemorrhage is present, and to establish airway continuity such as in a patient who presents with bronchopleural fistula and requires mechanical ventilation. Specific indications with bronchial blockers include: patients with difficult airways, patients with tracheostomy that require lung separation, selective lobar blockade, or whenever postoperative mechanical ventilation is contemplated.
This review focuses on the current methods used to achieve lung separation. The objectives include: selecting the proper size device, intubation issues, optimal positioning with the use of a flexible fibreoptic bronchoscope, potential complications, and the management of lung isolation devices and what to do when they do not work.
Author J. SwanevelderSource: Southern African Journal of Anaesthesia and Analgesia 14, pp 28 –30 (2008)More Less
Quantification of ventricular function, and in particular contractility, is the holy grail of intraoperative haemodynamic assessment. Over the past twenty-five years echocardiography technology has improved tremendously and intra-operative transoesophageal echocardiography (TOE) has become the gold standard cardiac monitor and diagnostic tool. There is a perception that intra-operative TOE provides valuable information that significantly influences clinical management and improves patient outcome. A TOE examination may provide vital information quicker and less invasive than the pulmonary artery catheter or any other haemodynamic monitor. Systolic and diastolic function of the left and right ventricles can visually be evaluated. Many echocardiography indices have been validated to also quantify function in a more objective way. Valvular and any other cardiac pathology can be excluded during a routine TOE examination. Ventricular wall motion abnormalities have been shown to be a highly sensitive indicator of regional myocardial ischaemia. A regional wall motion abnormality appears almost instantly after the onset of ischaemia in a specific segment and is detectable by echocardiography. As with many interventions, a full understanding of the limitations and possible artefacts is required. In future newer modalities like tissue Doppler imaging, strain rate, and contrast echocardiography will play an important role in the intraoperative assessment of ventricular function. 3D TOE is another brand new and exciting introduction to our perioperative practice. Perioperative echocardiography is here to stay and will fulfil a vital role for today's anaesthetist.
Author B. BrandstrupSource: Southern African Journal of Anaesthesia and Analgesia 14, pp 32 –37 (2008)More Less
Perioperative fluid therapy is the subject of much controversy, and the existing evidence seems contradictory. The aim of this paper is to present the (missing) evidence supporting the current standard fluid therapy, as well as the original trials examining the effects of fluid therapy on outcome of surgery.
To emphasise the fluid loss that actually occurs during surgery, the literature examining the evaporation from the abdominal wound, the fluid accumulations in the traumatised tissues, as well as the postulated changes in functional extracellular volume (i.e. the 'loss to third space') is briefly presented and critically analysed.
An attempt is made to evaluate all the trials examining the influence of fluid volume on outcome of surgery. The trials of goal-directed fluid therapy can be divided into two categories: the trials that examine the effect of zero fluid balance and the goal of normal bodyweight (the original restricted fluid trials), and the trials examining the effect of giving fluid to a target physiological value measured with either a pulmonary artery catheter or with an ultrasound Doppler device placed in the oesophagus. In addition to the goal-directed trials, the trials examining the effect of fixed volume fluid therapy will be presented. These 'fixed volume trials' concern mostly patients undergoing minor surgical procedures in an outpatient surgical setting.
The following conclusions are reached: current fluid therapy is not at all evidence based. The fluid losses that actually occur during surgery are highly overestimated. The perspiration from the surgical wound as well as the fluid accumulated in traumatised tissue is very small in elective surgery. The 'loss to third space' is based on flawed methodology and most probably does not exist.
The results of the goal-directed trials examining the effect of fluid therapy guided by a catheter in the pulmonary artery have not been unanimous, and the most exhaustive of these trials including 1 999 patients failed to show any benefit. The trials giving fluid to a maximal stroke volume guided by a Doppler in the oesophagus have several weaknesses, making the results of the trials very difficult to interpret, yet the method seems promising.
The trials focusing on zero fluid balance with the goal of normal body weight have shown that fluid overload with crystalloids causes harm, and avoidance of this fluid overload convincingly improves the outcome. This approach is confirmed by the trials giving a fixed volume of fluid during outpatient surgery, showing improved postoperative recovery by replacing the deficit caused by fasting. Patients undergoing major surgery should not be treated with a fixed fluid volume.
Source: Southern African Journal of Anaesthesia and Analgesia 14, pp 39 –43 (2008)More Less
Background: The dilemma of what to do if blood is unavailable (or in very short supply) when a patient is bleeding heavily has confronted all clinicians who work in the pre-hospital setting, operating room, intensive care unit or emergency department. This article reviews methods that are currently available and under investigation for bleeding control and resuscitation, including artificial oxygen carriers (AOCs), tourniquets, elevation / gravity, pro-coagulant technologies, haemostatic agents and minimisation of further blood loss by non-operative and minimally invasive surgical interventions.
Methods: The MEDLINE literature database, textbooks and the authors' 56 combined years of experience in anaesthesia, critical care and bloodless medicine associated with the Shock Trauma Center, Baltimore, Maryland, the Englewood Hospital and Medical Center and other hospitals with major blood use were resorted to in evaluating the management strategies described.
Results: A multitude of strategies and options are available. Infusions of AOCs will enhance oxygen carriage and can also be used for volume expansion. Haemoglobin-based oxygen carriers (HBOCs) are a major group of AOCs. HBOC therapy should include monitoring daily plasma haemoglobin (Hb) and haematocrit levels. HBOCs have limited half-life and decreasing plasma Hb, in the context of decreasing total Hb, indicates the need for re-dosing with HBOC. Total Hb, not haematocrit, is used for the assessment of anaemia, because haemodilution by the cell-free Hb solutions can cause haematocrit to be proportionally unrelated to total Hb. HBOCs can make patients appear jaundiced due to metabolism of free Hb. Interferences with laboratory and oximetry monitoring technology should also be considered. HBOCs, like erythropoietin, can act as haematinics and provide added benefits by stimulating erythropoiesis. There are still challenges that need to be resolved regarding the safety and efficacy of these products.
The application of external pressure (e.g. using tourniquets to occlude bleeding from arterial and venous sites and inflatable splints or compression bandages as a temporising means of haemorrhage control for major pelvic fractures) can minimise bleeding. Intra-abdominal packing is an excellent means of salvage when haemorrhage is profuse (e.g. from a major liver laceration) and blood is unavailable.
Intra-operatively, minimally invasive techniques and reduction of blood pressure can reduce surgical blood loss. Cell salvage technology and acute normovolaemic haemodilution will enable some vital surgeries to be completed with fewer transfusions or completely without blood. The use of pro-coagulant technologies, such as fibrin bandages, ChitoFlex dressing, and zeolitebased products (e.g. QuikClot®), can stop arterial and venous bleeding in a few minutes. Haemostatic agents such as recombinant Factor VIIa (rFVIIa) can reduce intra-abdominal bleeding (e.g. liver lacerations). The use of percutaneous screw fixation to stabilise orthopaedic fractures enables the reduction of bleeding that would normally be uncontrolled. Trauma patients have impaired erythropoiesis and a hypoferric state secondary to a complex network of bleeding and inflammatory mediators appearing within 12 hours of injury and lasting more than nine days. Erythropoietin therapy in this population may improve survival. If bleeding occurs intra-operatively, high FIO2, maintaining sedation, neuromuscular paralysis and intubation with mechanical ventilation will minimise oxygen consumption. The maintenance of normovolaemia with crystalloids and colloids and the initiation of blood conservation techniques described above are recommended.
Conclusions: External pressure, abdominal packing or insufflation, haemostatic technologies (bandages, rFVIIa), early orthopaedic fracture reduction with external fixation, interventional radiological embolisation, and minimally invasive percutaneous surgery are effective management strategies for managing bleeding without blood. AOCs function as both oxygen-carrying and volume-expanding tools to bridge the loss of oxygen delivery of blood during the first 10 days after injury until intrinsic reticulocytosis regenerates native red cell production. Used in combination with other resuscitation measures, these techniques and strategies can significantly reduce transfusion requirement and prove to be life saving in cases of severe bleeding where no transfusion is available.
Author T.H. StanleySource: Southern African Journal of Anaesthesia and Analgesia 14, pp 46 –50 (2008)More Less
There is a great deal of data to indicate that better knowledge of diseases, better preoperative preparations, better monitoring and better anaesthetics have significantly reduced mortality during general and regional anaesthesia in the past 60 years. Anaesthetic death rates of approximately one in 1000 in the 1940s were reduced to one in 10 000 in the 1970s, and are now estimated to be as low as one in 250 000 to one in 400 000 in 2008. This is about 250 times better that it was just 60 years ago. This paper will focus on the improvements in anaesthetic and analgesic agents and their delivery in the past 20 years and speculate on how these drugs and drug delivery systems will continue to get better in the future.
Author A. MilnerSource: Southern African Journal of Anaesthesia and Analgesia 14, pp 52 –57 (2008)More Less
Penetrating neck injury was first described 5 000 years ago on a piece of papyrus. Hugh Munro closed a longitudinal tracheal laceration in 1792 by using external straps. Horizontal lesions were sutured over a stent and the patientâ??s neck remained in the flexed position while the wound was allowed to heal.
Author K.M. KuczkowskiSource: Southern African Journal of Anaesthesia and Analgesia 14, pp 59 –62 (2008)More Less
Trauma in pregnancy is currently a leading cause of non-pregnancy-related maternal death, and maternal death remains the most common cause of foetal demise. The most common aetiologies of trauma in pregnancy include transportation accidents, falls, violent assaults and burn injuries. Head and neck injuries and haemorrhagic shock account for most maternal deaths secondary to trauma. Women of childbearing age are among the population at greatest risk for trauma. The pregnant trauma victim presents a unique spectrum of challenges to the healthcare team. Expeditious maternal resuscitation is the most effective method of foetal resuscitation. The management of pregnant trauma victims requires the anaesthesiologist, the obstetrician and the trauma surgeon to consider and understand the unique changes in anatomy and physiology that take place during pregnancy. This article reviews the current considerations for the optimal perioperative management of pregnant trauma victims.
Source: Southern African Journal of Anaesthesia and Analgesia 14, pp 63 –69 (2008)More Less
The experimental delivery of spinal anaesthetics to the desired heights in the body, even above the termination of the spinal cord (thoracic level), has been shown to be potentially very valuable. Since there is no blockade of the lower extremities, little caudal spread, a significantly larger portion of the body experiences no venal dilation, and may offer a compensatory buffer to adverse changes in blood pressure intra-operatively. Further, the dosing of the anaesthetic is exceedingly low, given the highly specific block to only certain nerve function along a section of the cord. Thirdly, the degree of muscle relaxation achievable without central or peripheral respiratory or circulatory depression is superior to that with general anaesthesia.
Results from Magnetic Resonance Imaging (MRI) studies indicate that the spinal cord lies anteriorly within its thecal boundaries in the apex of the thoracic curve. Intrathecal injections, therefore, at thoracic levels may have a greater absolute margin of error before needle contact with neural tissue - although the consequences of inadvertent contact are possibly more disastrous.
The thoracic CSE technique has been practised in twelve patients with cardiovascular and / or pulmonary problems. Despite bad haemodynamic situations and / or severe end-stage lung problems, abdominal surgery (i.e. cholecystectomy, bowel and vascular surgery) could be performed successfully with the thoracic CSE method, with low impact on the patient. Anaesthetic care of the patients would have been more difficult, with consequently larger impacts on haemodynamic and pulmonary function, should these surgeries have occurred under general anaesthesia - the usual anaesthetic technique of choice.
CSE techniques can be used in the thoracic region in patients who otherwise would receive general anaesthesia. High risk patients, with limited cardio-respiratory reserves, present challenges to the anaesthesiologist. Using the thoracic CSE technique in the thoracic space is extending the boundaries of regional anaesthesia.
Author J.A. DiNardoSource: Southern African Journal of Anaesthesia and Analgesia 14, pp 70 –72 (2008)More Less
SARS, bird flu and other scares - epidemic and pandemic preparedness in intensive care : SASA refresher textSource: Southern African Journal of Anaesthesia and Analgesia 14, pp 74 –78 (2008)More Less
Intensive care units are expensive facilities and as a consequence intensive care units are usually maximally utilised. An additional requirement for intensive care facilities is likely to occur during an epidemic. Any additional requirement has the potential to overwhelm existing intensive care resources and therefore it may become necessary to rapidly increase the capability of existing intensive care facilities. The lack of preparedness and proper procedures to facilitate urgent expansion of intensive care unit (ICU) facilities during severe acute respiratory syndrome (SARS) was exposed during the outbreak, and several lessons have been learned. Recommendations for adequate expansion are made on the basis that a reasonable standard of ICU care will be maintained. An assessment of the need for additional staff is made, however, it is unlikely that expansion beyond an additional 60% of current capacity will be possible, based primarily on the necessity for suitably qualified nurses. There is a requirement for prospective training of anticipated additional staff, as well as the establishment of infection control procedures, good communication procedures and the resolution of anticipated ethical dilemmas. Certain other preparations for expansion should also be completed in advance. These specifically include the fit testing of negative pressure respirators, sourcing of material and designs that will allow physical modifications to the ICU and additional equipment supply sourcing, bearing in mind that supply companies will be under pressure from more than one end-user.
Anaesthesia in the radiological suite (remote location) on an outpatient basis : SASA refresher textAuthor R.S. HannallahSource: Southern African Journal of Anaesthesia and Analgesia 14, pp 79 –80 (2008)More Less
The recent advances in diagnostic radiology and imaging studies have made these techniques an important part of the preoperative work-up of surgical patients. Today, most preoperative examinations are scheduled and performed on an outpatient basis. Most of these examinations are brief and cause no discomfort, but some are long and require immobility for a prolonged period.
Author A.T. BosenbergSource: Southern African Journal of Anaesthesia and Analgesia 14, pp 81 –83 (2008)More Less
Regional anaesthesia for children of all ages continues to develop since its re-introduction into clinical practice over 25 years ago. The need for improved postoperative pain management in children has been the driving force behind its continued growth in popularity worldwide. However, the analgesia so provided must be balanced against the risk of the regional technique. Improved equipment more suitable for children, the publication of large audits, and the introduction of portable ultrasound have all influenced clinical practice
Source: Southern African Journal of Anaesthesia and Analgesia 14, pp 84 –86 (2008)More Less
It has been estimated that 0.8% of children born in the United States will be diagnosed to have some form of congenital heart disease. (CHD) Many of these children will require surgery for noncardiac conditions that are commonly encountered during childhood (e.g. inguinal hernia, dental caries, or chronic tonsillitis). Moreover, many children with CHD have other associated noncardiac (e.g. orthopedic or genitourinary) congenital anomalies that require surgical repair. Many of these procedures are performed in general hospitals by noncardiac anesthesiologists. It is therefore essential that the anesthesiologist be knowledgeable, not only of the basics of pediatric anesthesia, but also of the pathophysiology of the cardiac lesions.
The world we live in - how should simulation be part of continuing professional education? : SASA refresher textAuthor W.B. MurraySource: Southern African Journal of Anaesthesia and Analgesia 14, pp 87 –89 (2008)More Less
At present, continuing professional development (also known as continuing medical education or CME) is expressed as "hours of training attended" and not as knowledge and / or skills attained. This is an insufficient and unsatisfactory method of ensuring that clinicians remain up to date with knowledge, skills and attitudes. There are several initiatives afoot to actually measure and evaluate clinicians to ensure they are able to perform their duties, albeit in a simulated environment. I believe an hour spent on active learning with simulation provides better professional development than a passive learning hour listening to a lecture.