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- Volume 16, Issue 1, 2010
Southern African Journal of Anaesthesia and Analgesia - Volume 16, Issue 1, 2010
Volumes & issues
Volume 16, Issue 1, 2010
Author P.R. PenfoldSource: Southern African Journal of Anaesthesia and Analgesia 16, pp 79 –80 (2010)More Less
Some diseases have become so common in our practice that they tend to pass by unnoticed, after a while. HIV infection is one of these, While most HIV-positive patients cause us no reason for concern, a regular revisiting of some of disease-related issues is certainly worthwhile.
Parturients are a fascinating group: seemingly young and healthy women present for procedures that aren't even necessary as a result of pathology, and robust physiology aids them in passing through our hands relatively unscathed. However, when unusual things start happening, this sense of security can vanish frighteningly quickly.
Author Z. FarinaSource: Southern African Journal of Anaesthesia and Analgesia 16 (2010)More Less
Author H. Van RooyenSource: Southern African Journal of Anaesthesia and Analgesia 16, pp 83 –88 (2010)More Less
Local anaesthetic agents reversibly block the action potentials responsible for nerve conduction. This action is demonstrable in any part of the nervous system and on every type of nerve fibre.
The Na+ selective transmembrane pore of the channel is presumed to reside in the centre of a nearly symmetrical structure formed by the four homologous domains of a 300 kDa protein complex. A change in the transmembrane potential towards the threshold value induces conformational changes in the molecule, which cause the Na+ channel to open. This gives rise to a rapid influx of Na+ with further depolarisation of the cell membrane. After it opens, the Na+ channel inactivates within a few milliseconds due to closure of an inactivation gate.
Source: Southern African Journal of Anaesthesia and Analgesia 16, pp 89 –90 (2010)More Less
Paediatric sedation guidelines : where we came from, where we are now, and current drug controversies : sedationAuthor C.J. CoteSource: Southern African Journal of Anaesthesia and Analgesia 16, pp 92 –95 (2010)More Less
The American Academy of Pediatrics (AAP) became interested in sedation disasters in 1983 when three children died in a single dental office. The AAP asked the Section on Anesthesiology to help develop guidelines for monitoring children sedated by non-anaesthesiologists. I had the good fortune to co-author this first sedation guideline in 1985. Subsequently, the AAP recognised that the guideline was being ignored by general paediatric practitioners, particularly those in the emergency room, radiology, and other areas where sedation is widely used. Therefore, the guideline was revised in 1992 with a new title, and emphasis was placed on "systems issues". A major source of confusion was the definition of "conscious sedation", which was defined as "a purposeful response to either a painful stimulus or a verbal command." Some practitioners interpreted reflex withdrawal to pain as being consistent with "conscious sedation", and this led to a number of accidents. This term is contradictory to what really happens to children, and is misleading.
Author A.M. TraversSource: Southern African Journal of Anaesthesia and Analgesia 16, pp 96 –100 (2010)More Less
The ICU is a hostile environment, and while pain is often the root cause of distress experienced by the patient in the unit, anxiety, dyspnoea, delirium and sleep deprivation may be additive or synergistic. Factors that provoke these components of distress include underlying medical conditions, acute medical / surgical illness, and "routine" critical care practices like mechanical ventilation, the presence of indwelling tubes and catheters, iatrogenic illness, medication side effects, turning and suctioning, and excessive noise and light in the ICU.
Author P. KrugerSource: Southern African Journal of Anaesthesia and Analgesia 16, pp 101 –103 (2010)More Less
Dexmedetomidine (Precedex®) is a selective alpha-2-receptor agonist that has been available for clinical use since 1999. Dexmedetomidine is currently registered in South Africa for post-operative sedation, after cardiac surgery, for 24 hours. The off label use of dexmedetomidine, for indications and duration of use other than registered, is widely published and accepted.
Author J.A. RoelofseSource: Southern African Journal of Anaesthesia and Analgesia 16, pp 105 –106 (2010)More Less
Currently, there is an increased demand for travelling sedationists working outside the operating room, for various reasons. One of these is that more procedures are being performed outside the operating room. In the United Kingdom, general anaesthesia for dental procedures outside the operating room has been prohibited, leading to an increased demand for sedation. It is also clear from evidence based studies that there is a low incidence of adverse events, not only during the sedation, but also in the postoperative period. The ultimate question still is, what does the travelling sedationist require in order to be a safe and effective sedationist? Obviously, the safety of the patient can never be compromised.
Author G. LamacraftSource: Southern African Journal of Anaesthesia and Analgesia 16, pp 108 –110 (2010)More Less
Why some patients develop chronic pain after an acutely painful event remains an enigma. For example, over 90% of the population will experience acute back pain at some time in their lives. In most cases this resolves but, in a few, it does not, even though these patients have radiologic pathology similar to those in whom the pain does improve.
Similarly, there are few people who escape the hands of the surgeon. What is becoming increasingly apparent is that those who do experience the sharp end of the scalpel frequently experience persistent pain as a result of the damage caused by this instrument. The reasons for this chronic post-surgical pain are discussed in this presentation, as are possible preventative strategies.
Author C.L. OdendaalSource: Southern African Journal of Anaesthesia and Analgesia 16, pp 111 –114 (2010)More Less
"Pain" can be defined as an unpleasant sensory and emotional experience associated with true or potential tissue damage, or described in terms of such damage. Pain is always subjective.
According to the Stedman's Medical Dictionary, "analgesia" : is a condition in which nociceptive stimuli are perceived but are not interpreted as pain. This is usually accompanied by sedation without loss of consciousness.
An analgesic, therefore, is a compound capable of producing analgesia, i.e. one that relieves pain by altering perception of nociceptive stimuli without producing loss of consciousness. Analgesics mostly function as central nervous system depressants. Specific receptors play a role in this regard, namely mu-receptors. Drugs acting on these receptors are classified as analgesics and include morphine, pethidine and codeine. They are also referred to as narcotic or opioid analgesics. Tramadol is only partly an opioid analgesic, i.e. ± 30%. The rest have a mono-aminergic function.
Non-steroidal anti-inflammatory (NSAIDs) are drugs with analgesic effects, but are not classified as narcotic analgesics. Their mechanism of action is totally different from that of the opioid narcotics.
Author R.V. PuruggananSource: Southern African Journal of Anaesthesia and Analgesia 16, pp 116 –120 (2010)More Less
Purpose of refresher course This refresher course reviews the rationale for using intravenous anaesthesia for thoracic operations and the drugs and equipment required.
Recent findings Recent studies examining whether intravenous anaesthesia offers a physiological advantage over inhalational anaesthesia for thoracic surgery remain inconclusive. Nevertheless, intravenous anaesthesia is inarguably preferable for certain thoracic procedures incompatible with effective delivery of inhalational anaesthetics. Additionally, TIVA offers advantages in procedures conducted in non-ideal environments, such as offsite or austere scenarios.
Summary TIVA is indicated for procedures in which inhalational anaesthetics may not be safely or effectively delivered, including endobronchial procedures using flexible or rigid bronchoscopy and proximal airway-disrupting surgeries. TIVA may also be beneficial in lung volume reduction surgery, lung transplantation, and thymectomy. In addition, TIVA is safer and more practical for thoracic procedures performed outside of the operating room, such as offsite locations, in the military field, or impoverished areas of the world. Propofol, dexmedetomidine, ketamine, and remifentanil may be used in combination with anaesthetic depth monitoring to execute an effective TIVA regimen. Target controlled infusion may improve the delivery of TIVA and is a focus for future research.
Author G. WilsonSource: Southern African Journal of Anaesthesia and Analgesia 16, pp 124 –126 (2010)More Less
Total intravenous anaesthesia (TIVA) has grown rapidly in popularity over the last two decades in both adult and paediatric anaesthesia. This rapid increase in popularity is in part due to the widespread availability of drugs with favourable pharmacological properties and the development of new concepts in pharmacokinetic modelling, as well as advances in computer technology that have allowed the development of sophisticated anaesthetic delivery systems. This has led to refinements in blood plasma concentration targeting and dosing adjustments. A target controlled infusion (TCI) is an infusion controlled by a real time pharmacokinetic model that achieves a user defined blood or tissue concentration of a drug.
Author A.Y. SchureSource: Southern African Journal of Anaesthesia and Analgesia 16, pp 127 –129 (2010)More Less
In these times of highly subspecialised medicine, many anaesthesiologists in the US think of neonatal resuscitation as the sole responsibility of neonatologists and paediatricians. But does this role assignment really release anaesthesiologists from the obligation to know how to perform an effective resuscitation of a newborn in the delivery room?
The rational use of recombinant factor VIIa in the treatment of major intractable bleeding in the trauma patient : resuscitation updateAuthor J. StrydomSource: Southern African Journal of Anaesthesia and Analgesia 16, pp 130 –133 (2010)More Less
Background : The off-label use of recombinant factor VIIa (rFVIIa / Eptacog Alfa / NovoSeven®) in trauma patients with massive haemorrhage has increased since 1999. Some clinicians see its role as a prophylactic drug to prevent major blood loss, while others use it as a rescue drug in life-threatening haemorrhage. There has been much debate regarding its clinical application, effectiveness, thromboembolic potential and cost / benefit ratio. A literature review was done to attempt to clarify some of these issues.
Methods : An electronic literature search of Medline and Pubmed databases was conducted applying keywords: NovoSeven, rFVIIa, recombinant FVIIa, Eptacog Alfa, trauma, major blood loss.
Results : rFVIIa has been used off-label in a variety of clinical settings either to prevent blood loss, or to treat intractable major haemorrhage. This includes several case reports and cohort studies in the trauma setting. Unfortunately there are only two randomised clinical trials (RCT) available regarding the use of rFVIIa in trauma. These RCTs were small and did not show significant benefit in favour of rFVIIa. There is still not sufficient level 1 evidence to support the routine use of rFVIIa in trauma patients, either prophylactically or as first line treatment for major haemorrhage. It also seems that the drug has a higher potential to cause thromboembolic complications than initially reported. It is very expensive and therefore has an unfavourable cost / benefit ratio. In the absence of good evidence of benefit, expert opinion regards rFVIIa as drug to be used only in life-threatening major haemorrhage where conventional treatment has failed.
Source: Southern African Journal of Anaesthesia and Analgesia 16, pp 135 –137 (2010)More Less
Survival after out-of-hospital cardiac arrest is linked to the rapid provision of effective external cardiac compressions, defibrillation and appropriate post-resuscitation advanced cardiac life support. Effective provision of these interventions requires strong links in the chain from pre-hospital to hospital based systems. Transport of the patient during resuscitation efforts to emergency departments, and interfacility transfer of patients post-resuscitation for definitive care, have not been demonstrated to increase survival.
This article will explore some of these issues, in a South African, pre-hospital context.