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- Volume 14, Issue 6, 2008
Southern African Journal of Anaesthesia and Analgesia - Volume 14, Issue 6, 2008
Volume 14, Issue 6, 2008
Author Christina LundgrenSource: Southern African Journal of Anaesthesia and Analgesia 14 (2008)More Less
As 2008 draws to a close we present you with our final edition for this year. We have two articles on peri-operative pain management, something which we as anaesthesiologists do not seem to manage terribly well. The first article is a study from Tunisian colleagues comparing paravertebral block with continuous intercostal nerve block after thoracotomy, and the second is a practical and comprehensive review by Jenny Thomas on peri-operative pain management, particularly in children.
Charcoal-roasted plantain and fish vendors in Port Harcourt : a potential anaesthetic high risk group? : scientific letterSource: Southern African Journal of Anaesthesia and Analgesia 14, pp 7 –9 (2008)More Less
A survey of charcoal-roasted plantain and fish (CRPF) vendors in Port Harcourt, Nigeria was carried out to determine if they were a potential anaesthetic high risk group. Questionnaires which contained vendor's biodata and educational qualification including information on hours of exposure as well as number of years in the business and respiratory symptoms if present were filled by the authors in the presence of the vendors. Oxygen saturation and heart rate were recorded using the Nonnin 9250 portable battery-operated oximeter. Results were programmed into Microsoft EXCEL work sheet and data analysed.
A total of 102 vendors were visited at their place of work over a three month period. Two declined to be interviewed leaving 100 vendors. All vendors were women aged 16 to 60 years (mean 34.3 years). More than half of the vendors (52%) had secondary level education. Seventeen per cent were part-time vendors while 83% were full-time. Number of years of exposure ranged from 1 to 30 years (Mean 6.4 years). The daily duration of exposure ranged from 4 to 14 hours (mean 7.7 hours). Mean oxygen saturation was 97%, while mean pulse rate was 85bpm. There were no significant respiratory symptoms.
We conclude from this survey that outdoor cooking or roasting with charcoal less than 14 hours daily for less than 10 years may not be enough to cause respiratory problems or pose any significant anaesthetic risk.
Author J. ThomasSource: Southern African Journal of Anaesthesia and Analgesia 14, pp 11 –17 (2008)More Less
Acute injuries, which include surgical operations, cause a number of physiological changes. Peripheral sensitisation occurs after injury to a nerve (cut skin, surgery to tissue) when an increase in response to stimuli by the peripheral nervous system takes place. Nerve fibres, which do not usually transmit pain, are now more sensitive, and do send painful stimuli. This will impact on the central nervous system, where increased noxious input causes a number of different responses. These include muscle spasms and increased sympathetic stimulation. The resultant increased oxygen and calorie consumption will impact particularly on the growth of neonates and infants.
A prospective, randomised comparison of continuous paravertebral block and continuous intercostal nerve block for post-thoracotomy pain : original researchSource: Southern African Journal of Anaesthesia and Analgesia 14, pp 19 –23 (2008)More Less
Background : This study aimed to compare paravertebral block and continuous intercostal nerve block after thoracotomy.
Methods : Forty-six adult patients undergoing elective posterolateral thoracotomy were randomised to receive either a continuous intercostal nerve blockade or a paravertebral block. Opioid consumption and postoperative pain were assessed for 48 hours. Pulmonary function was assessed by forced expiratory volume in 1 s (FEV1) recorded at 4 hours intervals.
Results : With respect to the objective visual assessment (VAS), both techniques were effective for post thoracotomy pain. The average VAS score at rest was 29±10mm for paravertebral block and 31.5±11mm for continuous intercostal nerve block. The average VAS score on coughing was 36±14mm for the first one and 4 ±14mm for the second group. Pain at rest was similar in both groups. Pain scores on coughing were lower in paravertebral block group at 42 and 48 hours. Post-thoracotomy function was better preserved with paravertebral block. No difference was found among the two groups for side effects related to technique, major morbidity or duration of hospitalisation.
Conclusion : We found that continuous intercostal nerve block and paravertebral block were effective and safe methods for post-thoracotomy pain.
A comparison of induction of anaesthesia using two different propofol preparations : original researchSource: Southern African Journal of Anaesthesia and Analgesia 14, pp 25 –29 (2008)More Less
Background : Investigators have reported inter-patient variability with regard to propofol dosage for induction of anesthesia, since early dose finding studies. With the arrival of generic formulations of propofol, questions have arisen regarding further variability in dose requirements. Various studies have confirmed that generic propofol preparations are pharmacokinetically and pharmacodynamically equivalent to Diprivan®. Nevertheless a number of practitioners are under the impression that certain generic propofol preparations require greater doses for induction of anaesthesia than does Diprivan®.
Methods : 20 female patients of ASA status I-II, between the ages of 18-55 years, scheduled for routine surgery were randomly allocated to two groups to undergo induction of anaesthesia using two different propofol formulations; Diprivan® and Propofol 1% Fresenius®. Either preparation was administered using a target-controlled infusion of propofol (STEL-TCI) targeting the plasma (central) compartment at a concentration of 6 µg.ml-1, employing the pharmacokinetic parameters of Marsh et al. A processed EEG (bispectral index) was continuously recorded. Loss of consciousness (LOC) was regarded as the moment at which the patient could not keep her eyes open and was confirmed by the absence of an eyelash reflex. At this point propofol administration was discontinued and data were recorded for a further two minutes, before administering an appropriate opioid and / or nitrous oxide / volatile agent and / or muscle relaxant to maintain anaesthesia. Time to LOC after start of propofol administration, and the dose of propofol administered during induction were annotated.
Results : There were no demographic differences between the groups. There were no differences between the groups with regard to the mean dose for LOC, time to LOC and to the mean BIS values obtained at the following stages: awake, at LOC, at 1 and 2 minutes after LOC as well as the lowest recorded value.
Conclusions : Our results confirm that the two propofol formulations that we studied, are pharmacologically equivalent with regard to induction of anaesthesia. Other mechanisms can explain the variability in clinical response to bolus administration of propofol. The most important is the recirculatory or "front-end" kinetics of propofol in which cardiac output plays a major role, as well as the rate of drug administration. Emulsion degradation can also influence dose-response and in this regard it should be noted that the addition of foreign substances such as lignocaine, can result in rapid deterioration of the soyabean emulsion.
Source: Southern African Journal of Anaesthesia and Analgesia 14, pp 31 –36 (2008)More Less
Background : The re-usable Classic laryngeal mask airway (LMA®) is widely used. There are concerns regarding the transmission of pathogens. Disposable airway devices provide a cost-effective alternative. We performed a side by side clinical comparison of these devices applicable to the South African context.
Methods : Adult ASA 1-3 patients (30 - 100 kg) presenting for elective peripheral surgery in Tygerberg Academic Hospital were randomised to receive the gold standard Classic LMA®, or one of four disposable devices. They all received a standardised anaesthetic with propofol, fentanyl and isoflurane in 40% O2 / N2O. Insertion technique, mask sizes and maximum cuff volumes were per manufacturer's instructions. The cuff was inflated to achieve an adequate airway seal (no audible leak at an airway pressure of 20cm H2O), or to the maximum recommended volume. Cuff and airway pressures were measured continuously. A protocol was followed for repeated or failed attempts. 115 of the proposed 130 patients were recruited. Categorical data was analysed using Chi squared tests, and one-way ANOVA was performed on parametric data. An alpha level of 0.05 was accepted.
Results : The patients were of comparable age, weight, ASA grade and airway grading. There were no statistical differences in the number of times the airway device size had to be changed (p = 0.627), ease of insertion (p = 0.357) or insertion attempts (p = 0.909). Only the Cobra PLA was graded as "Grade 4 : impossible to establish an airway" in 10% of cases, and the insertion time with this device was prolonged (p = 0.018). The Cobra PLA predictably differed from the other groups in cuff volumes (p = 0.001). Cuff pressures were significantly higher in the Ambu and LMA Unique (p = 0.001). Maximum airway pressure attainable after 5 minutes was significantly higher in the Ambu (p = 0.036). Airway trauma as graded by visible blood on the device was low, and similar between groups (p = 0.237). Secretions were negligible in 67.8% patients and there was no difference in the amount of suctioning required (p = 0.094). Patient comfort was exceptional and comparable, achieving similar visual analogue scores for sore throat (p = 0.742), dysphagia (p = 0.760) and hoarseness (p = 0.258). No complications were noted.
Conclusions : We found no difference in routine clinical practice between the Classic LMA®, LMA Unique, Portex Soft Seal, Ambu and Cobra PLA in terms of ease of insertion, number of attempts, size changes, patient comfort or airway trauma. The Ambu device allowed an airway seal at higher pressures. The Cobra devices had a prolonged average insertion time. The Cobra devices were the only ones found impossible to achieve a satisfactory airway after 3 attempts in 10% of cases, although this did not reach statistical significance.
Antiemetic prophylaxis with promethazine or ondansetron in major gynaecological surgery : original researchSource: Southern African Journal of Anaesthesia and Analgesia 14, pp 39 –42 (2008)More Less
Background : Postoperative nausea and vomiting remain a significant cause of morbidity among patients undergoing general anaesthesia. The optimal strategy for prevention, however, remains controversial. This study evaluated the efficacy of ondansetron 8 mg compared with promethazine 25 mg or placebo for the prevention of nausea and vomiting in patients undergoing elective major gynaecological surgery.
Methods : Seventy-five patients received intravenous injection of the study medication (ondansetron-25, promethazine-25 or placebo-25) immediately before the induction of anaesthesia. Nausea and vomiting were assessed over a 24-hour postoperative period.
Results : Nausea occurred in 20%, 40% and 72% of the promethazine, ondansetron and placebo groups respectively (p = 0.001). The overall incidence of vomiting was 12%, 16%, and 60% (p = 0.000) for promethazine, ondansetron and the placebo respectively. Postoperative drowsiness was prominent in the promethazine group. There was no significant difference in effectiveness between promethazine and ondansetron.
Conclusions : Promethazine 25 mg was significantly more effective than ondansetron 8 mg in the prevention of postoperative nausea and vomiting. Promethazine is inexpensive and the cost of drugs is of importance in developing African countries. Drowsiness was a significant side-effect with promethazine, and this will be a disadvantage in ambulatory surgery.
Evaluation of gabapentin in attenuating pressor response to direct laryngoscopy and tracheal intubation : original researchSource: Southern African Journal of Anaesthesia and Analgesia 14, pp 43 –46 (2008)More Less
Background : To evaluate effect of gabapentin in attenuation of haemodynamic responses to direct laryngoscopy and tracheal intubation.
Methods : Hundred patients undergoing elective surgery were randomly allocated to two groups of 50 patients each. Patients in group A received gabapentin 800 mg and patients in group B received placebo capsules the night before and on the morning of surgery. Anaesthesia was induced with propofol and vecuronium. Systolic, diastolic, mean arterial blood pressures (SAP, DAP, MAP) and heart rate (HR) were recorded before and after the induction of anesthesia and 0, 1, 3, 5 and 10 min after tracheal intubation.
Results : SAP was significantly lower in the gabapentin as compared to the control group 0, 1, 3, 5 and 10 min after intubation [121 vs 135 ( P<0.001), 117 vs 132 (P<0.001), 112 vs 124 (P<0.001), 110 vs 118 (P<0.05) and 107 vs 112 ( P<0.05) respectively]. DAP also was lower in the gabapentin group 0, 1, 3, and 5 min after intubation [77 vs 87 (P<0.001), 74 vs 84 (P<0.001), 70 vs 78 (P<0.001) and 68 vs 74 (P<0.05)]. MAP also was lower in the gabapentin group 0, 1, 3, and 5 min after intubation [92 vs 103 (P<0.001), 88 vs 100 (P<0.001), 84 vs 93 (P<0.001) and 82 vs 88 (P<0.05)]. HR also was lower in the gabapentin group 0, 1 and 3 min after intubation [90 vs 98 (P<0.05), 88 vs 95 (P<0.001) and 84 vs 90 (P<0.05)].
Conclusion : Gabapentin, under the present study design attenuates the pressor response associated with laryngoscopy and tracheal intubation but tachycardiac response is not completely eliminated.
Source: Southern African Journal of Anaesthesia and Analgesia 14, pp 47 –49 (2008)More Less
Assessment of QT interval changes in vascular surgery
Can an aerobic exercise training programme improve fitness in patients awaiting aortic surgery?
Carotid endarterectomy and gender: differences in health-related quality of life perception
Dexmedetomidine infusion vs magnesium infusion as an adjuvant in total intravenous anaesthesia for patients undergoing femoropopliteal bypass surgery
Influence of anaesthsia type on outcome after thoracic endovascular aneurysm repair
Ultrasound evaluation of the anatomical characteristics of the internal jugular vein and carotid artery : for facilitation of internal jugular vein cannulation