Southern African Journal of Anaesthesia and Analgesia - Volume 18, Issue 6, November 2012

During the course of 1997, deaths during pregnancy, childbirth and the puerperium were made notifiable events in South Africa in terms of the National Policy Health Act (number 116 of 1990) of South Africa. This was done in recognition of the need to reduce maternal mortality, which is considered a basic health indicator that reflects the adequacy of health care. The exact maternal death rate in South Africa was not known at the time, because of a lack of accurate record-keeping. However, the World Health Organization (WHO) had estimated that almost 600 000 women were dying worldwide annually as a result of pregnancy-related conditions, particularly in the developing world.

The National Committee on Confidential Enquiries into Maternal Deaths (NCCEMD) has assessed maternal deaths in South Africa since 1997. Reports have been produced since 1999, culminating in the latest triennial report (2008-2010). The anaesthetic chapter from this report is published in SAJAA to improve dissemination of the information.

The number of reported deaths due to anaesthesia continues to increase. There were 121 reported this triennium. This represents 2.5% of all maternal deaths and 5.4% of deaths directly related to complications of pregnancy. One hundred and eighteen of these were available for review and 92 were assessed as being directly due to anaesthesia. Spinal anaesthesia accounted for 73 (79%) of the deaths and general anaesthesia 16 (17%). Two deaths were associated with sedation and one with epidural anaesthesia. The percentage of deaths caused by spinal anaesthesia increased in this triennium to 79%. Again, two thirds of these deaths resulted from poor treatment of well-recognised complications of spinal anaesthesia (hypotension and high motor block). The most common cause of death following general anaesthesia was difficult or failed intubation, which occurred in 50% of cases. Lack of basic skills in anaesthesia, including assessment and resuscitation, were identified. As in previous triennia, most anaesthesia-related deaths occurred at level 1 hospitals (70%). This reflects the need for skilled qualified anaesthetic care at these hospitals.

Biomarkers are important in diagnosis, assessment of disease severity, risk stratification and therapeutic decision-making. Recent studies strongly suggest that there is a role for B-type natriuretic peptide (BtNP) as a powerful prognostic predictor in both the preoperative and postoperative setting. An understanding is required of the specific statistical methodology that is used to assess the value of biomarkers. The main aim of this paper was to discuss the current role that BtNP plays in perioperative risk prediction.

Objectives : The cost of various anaesthetic techniques fluctuates and is seldom transparent, because of complicated anaesthetic protocols. The theoretical costs of different anaesthetic techniques were compared in this study.

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Design : This comparative study utilised protocols that determined the cost of inhalational anaesthesia, based on evidence from relevant literature. Propofol target-controlled infusion (TCI) was used as the intravenous protocol [Alaris® PK syringe pump (Schnider model), Cardinal Health, UK].

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Setting and subjects : No patients were involved in this theoretical cost analysis.

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Outcome measures : The calculated costs of high- vs. low-flow inhalational anaesthesia and inhalation vs. intravenous anaesthesia with propofol, with or without N2O, and procedures of a longer and shorter duration were compared.

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Results : Trends were noted. High-flow inhalational anaesthesia tended to be more expensive than low-flow inhalational anaesthesia. The savings that were gained by implementing low-flow anaesthesia increased with the duration of procedure. The savings were greater when less soluble inhaled anaesthetics were used. Isoflurane and halothane anaesthesia cost more when N2O was added. Inhalational anaesthesia with isoflurane was the most cost-effective option consistently. Anaesthesia with desflurane was always the most expensive option. Propofol TCI was less expensive than sevoflurane for long procedures.

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Conclusion : Anaesthetic drugs account for only 3-4% of the total cost of a surgical procedure, but economic use thereof frees up resources for other essentials in financially challenging times. Isoflurane should be used widely. N2O should probably be used conservatively as it increases the anaesthetic cost and contributes to pollution and ozone depletion. Propofol TCI can be considered instead of sevoflurane inhalational anaesthesia for longer procedures.

Background : Knee replacement surgery is an operation that is performed on older patients, with a few exceptions. Many of these patients have co-existing diseases and have had previous surgery, of which lumbar spinal surgery is of particular relevance. Neuraxial anaesthesia is the anaesthetic of choice.

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Method : This study offers a practical approach to how anterioposterior and lateral X-rays of the lumbar spine contribute to the ease and safety of the neuraxial anaesthesia procedure. The study group comprised 100 patients, scheduled for knee replacement surgery. The patients had to have undergone previous lumbar spinal surgery. This was the only prerequisite.

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Results : The success rate of neuraxial anaesthesia improved progressively during the study. It became clear that specific clinical aspects had potential for future application in this particular group of patients. Only four of a total of 23 combined spinal epidural procedures were not successful. There were three dural taps without any post-dural puncture headaches being experienced. Spinal blocks totalled 77, of which two were incomplete and five complete failures.

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Conclusion : Calculated performance of neuraxial anaesthesia on patients who had undergone previous lumbar spinal surgery set the scene for a more predictable and largely atraumatic outcome.

Objectives : The aim of this study was to describe the effect of dexmedetomidine on haemodynamic stability in the intraoperative period, as well as on the pressor response to intubation and extubation and the requirement of inhalation anaesthetics and recovery.

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Design : A simple descriptive study.

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Settings and subjects : The study was conducted in a tertiary hospital in India from June 2010-June 2011. The 81 American Society of Anesthesiologists classification I and II patients who were enrolled in the study were given a loading dose of dexmedetomidine 1 µg/kg, followed by a continuous infusion of 0.5 µg/kg/hour. Supplementation with end-tidal sevoflurane 1-2% was considered when heart rate (HR) and mean arterial pressure exceeded 20% of baseline values. On completion of surgery, the time taken to discontinue dexmedetomidine infusion and the extubation time were recorded.

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Outcome measures : Changes in haemodynamic variables from baseline and a comparison of means were analysed by paired t-test for each time interval.

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Results : There was significant reduction in HR and systolic blood pressure following the loading dose of dexmedetomidine (12.31% and 8.82% respectively), in the intraoperative period (17.71% and 16.5% respectively), and during intubation and extubation (p-value < 0.001). None of the patients required supplementary doses of analgesics in the intraoperative period. Only 13 patients required end-tidal sevoflurane of 1% during the study. Seventy per cent of patients could be extubated within five minutes of discontinuing the infusion.

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Conclusion : Dexmedetomidine provided a stable haemodynamic profile in the perioperative period and a blunted pressor response to intubation and extubation. With its use, there was a minimal requirement for analgesics and inhalational agents. It had an acceptable recovery profile.

Objectives : To determine the effect of different levels of positive end-expiratory pressure (PEEP) on pulse pressure variation (PPV).

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Design : An observational study.

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Setting : Operating theatres of a tertiary training hospital.

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Subjects : Ventilated patients who required intra-arterial blood pressure monitoring.

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Outcome measures : PPV during different levels of PEEP.

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Method : Patients were anaesthetised by means of a standard technique and ventilated with a tidal volume of 9 ml/kg ideal body mass. The PPV was calculated at PEEP levels of 2, 5, 8 and 10 cmH2O. PPV was compared at the various PEEP levels.

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Results : PPV at a PEEP of 8 cmH2O and 10 cmH2O was significantly larger than that at 2 cmH2O (p-value < 0.001). PPV at a PEEP of 10 cmH2O was significantly larger than that at 8 cmH2O (p-value < 0.001). PPV at a PEEP of 8 cmH2O was larger than that at 5 cmH2O (p-value = 0.002). PPV at a PEEP of 2 and 5 cmH2O did not differ significantly (p-value = 0.194).

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Conclusion : We have demonstrated that, in patients with normal lungs, PEEP has a significant influence on PPV. PPV may be overestimated if PEEP ≥ 8 cmH2O is applied in patients who are ventilated with a tidal volume of 9 ml/kg. It is recommended that in patients with healthy lungs PPV should be measured at a standardised PEEP of ≤ 5 cmH2O.

Objective : Postanaesthetic shivering is a recognised complication of general and regional anaesthesia. Pharmacological and nonpharmacological methods have been used to prevent shivering. This study was conducted to determine the efficacy of ketamine when compared with pethidine and placebo for the prevention of postanaesthetic shivering.

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Design : A randomised, double-blind study was conducted.

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Setting and subjects : This study was conducted on 90 American Society of Anesthesiologists (ASA) I and II patients of both genders, aged 18-70 years, who were to undergo surgery under general anaesthesia. Patients were randomised into three equal groups: Group S received a saline placebo, Group P received pethidine 20 mg and Group K received ketamine 0.5 mg/kg. The study medication was given within 20 minutes of the estimated end of surgery.

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Outcome measures : Haemodynamic parameters were noted before, during and after anaesthesia. Tympanic temperature was recorded during the intraoperative period, on arrival in the recovery room (T0) and subsequently at 10 minutes (T10), 20 minutes (T20) and 30 minutes (T30). Shivering was graded on a four-point scale. Pain was assessed and recorded by means of a visual analogue scale. Any untoward side-effects were also noted.

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Results : The demographic profile of the patients was similar. The number of patients shivering at T0 and subsequently at T10 and T20 was significantly less in Group K and Group P than in Group S (p-value < 0.005). However, there was no difference between Group P and Group K (p-value > 0.005). Thirty minutes after the end of the anaesthetic, there was no difference between the groups (p-value > 0.005). Haemodynamic parameters were similar throughout. The incidence of adverse effects was similar.

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Conclusion : Ketamine was found to be as effective as pethidine in preventing postanaesthetic shivering without increasing the risk of side-effects.

A 50-year-old male [American Society of Anesthesiologists (ASA) grade II] was scheduled for lower limb orthopaedic surgery. The subarachnoid space was localised with difficulty at L3/4 interspace and 3 ml of hyperbaric bupivacaine was given. Within a few minutes, the patient developed aphasia with a very high sensory block extending to C2 dermatome, followed by apnoea. The patient remained haemodynamically stable throughout surgery and respiration resumed within five minutes. Inadvertent subdural deposition of local anaesthetic was speculated to be the cause of this unusual presentation.

Recently, I became aware of a practice whereby patients are routinely evaluated by specialist physicians prior to undergoing anaesthesia and surgery. The anaesthesiologists concerned subsequently paid a very brief visit to their patients immediately before surgery and examined the patients cursorily. I am unsure if this practice is widespread. Nevertheless, I am aware of a number of such cases.

We report on the occlusion of the bronchus of a non-ventilated lung by a bronchial carcinoid tumour. This prevented the collapse and atelectasis of the corresponding lung. Lung collapse was facilitated by guiding an epidural catheter past the lesion.

Steph Potgieter was born on 22 September 1928 and passed away on 9 April 2012. He studied medicine at the University of Pretoria, where he received his MBChB in 1951. After internship in Bloemfontein, he participated in general practice from 1952-1956 in the city. He trained in anaesthesiology at Karl Bremer Hospital from 1956-1959 and received the qualification of MMed Anaesthesiology from Stellenbosch University.

Patrick Anthony Foster died peacefully at his home in Hershey, Pennsylvania, on 23 April 2012, aged 86 years. Pat was born in London of English and South African parents and went to school in both countries. He received his South African schooling at St Andrew's College in Grahamstown. Having matriculated at the age of 14, he did a post-matric year. However, he was obliged to obtain special permission to study medicine at such a young age. He received an MBChB degree from the University of Cape Town and did his internship at Groote Schuur Hospital in orthopaedics and neuropsychiatry.