Evaluation of the Mediseus epidural simulator.

The demand for increased patient safety has led to greater use of simulation training of health professionals performing medical procedures. The study aim was to evaluate the usefulness of the Mediseus® Epidural Simulator in teaching basic epidural needle-handling skills. Three groups of 15 anaesthetists (Novice=zero to two year anaesthesia trainees; Intermediate=three- to five-year anaesthesia trainees; Expert=consultants and regional-specialist anaesthetists) from three different medical centres participated. Each participant performed 20 simulated epidural needle insertions and was scored on several parameters (e.g. time, success of the insertion, bone collisions). Following familiarisation with the simulator and the needle insertions, participants answered seven questions on the applicability of the simulator to the teaching of basic epidural needle-handling skills. There was a clear learning effect with regard to the simulation procedure time, this decreasing throughout the experiment (P=0.037). There was no significant influence of either group or experience with the simulator in the study on the number or type of errors made. The quality of the simulation was scored 2.3 out of 5.0 (for bone simulation) and 4.7 (for loss-of-resistance simulation). All groups considered that the simulator was best suited for training prospective anaesthetists. Each group rated the usefulness of the simulator for training novices at greater than 3.0 out of 5.0. The Mediseus® Epidural Simulator seems to be an appropriate training device for an introduction to epidural needle insertion. For medical professionals with procedural knowledge, the simulation is not realistic enough and the simulator did not distinguish between the groups based on the errors made.

The effects of sevoflurane on isolated gravid human myometrium.

The volatile anaesthetic agents are known to influence uterine muscle tone. All of the agents studied to date have been found to produce uterine relaxation. This property has been used to produce therapeutic uterine relaxation for difficult obstetric deliveries and the Ex Utero Intrapartum Treatment (EXIT) procedure. This study describes the effects of sevoflurane on isolated human myometrium at concentrations of 0.1, 0.25, 0.5, 0.75, 1.0, 1.5, 2.5 and 3.5 MAC. Sevoflurane produces dose-dependent depression of uterine muscle contractility with an ED50 of 0.94 MAC. Frequency of contraction was increased at concentrations of 2.5 MAC and greater. At concentrations of 3.5 MAC and above, uterine activity was virtually abolished.

Airway management on placental support (AMPS)--the anaesthetic perspective.

Neonatal airway obstruction has been reported to have a high mortality. Antenatal diagnosis of this condition is now possible. Anaesthetic and surgical techniques have been developed that allow neonatal airway obstruction to be managed at delivery, while the fetus remains oxygenated via the placental circulation. Three case studies are presented, and the anaesthetic issues for mother and fetus/neonate are discussed with reference to previously published cases of airway management on placental support. In particular, techniques for uterine relaxation and maintenance of placental circulation are explored. The history of these procedures and issues of planning and logistics are also discussed.

The in-vitro effects of sevoflurane and desflurane on the contractility of pregnant human uterine muscle.

The effect of desflurane and sevoflurane on the contractility of the uterus was examined in vitro on strips of human myometrium obtained at the time of elective cesarean section. Small strips (1 mm x 2 mm x 10 mm) of muscle were prepared and suspended in an organ bath containing oxygenated physiological saline. Force of contraction was recorded continuously using an isometric tension transducer. Following the onset of regular spontaneous contractions, baseline measurements were obtained and the strips were exposed to varying concentrations of sevoflurane or desflurane corresponding to 0.5, 1.0 and 1.5 minimum alveolar concentration (MAC). Sevoflurane depressed contractility to 72 +/- 18% of control at 0.5 MAC, 37 +/- 15% at 1.0 MAC and 27 +/- 16% at 1.5 MAC compared with 65 +/- 14 of control at 0.5 MAC, 43 +/- 18% at 1.0 MAC and 22 +/- 11% at 1.5 MAC for desflurane. The degree of depression of uterine muscle contractility produced by both these agents was significantly different from control at all concentrations. In conclusion, both sevoflurane and desflurane depress the contractility of isolated pregnant human myometrium at concentrations of 0.5, 1.0 and 1.5 MAC. These agents produce a similar degree of depression of uterine muscle contractility.

A standardized, uniform and universal dental chart for documenting state of dentition before anaesthesia.

It is vital to have adequate and precise documentation of the condition of a patient's dentition before commencing an anaesthetic. The incidence of dental damage during anaesthesia is not low. To the authors' knowledge, there is no standardized method used by anaesthetists to document the state of a patient's dentition. We propose the introduction of a standardized uniform dental chart to enable anaesthetists to accurately document the condition of their patients' teeth. This vital information can be easily obtained during the preanaesthetic assessment. With the increase in medical litigation and demands for adequate documentation, we believe this chart can become an invaluable part of every hospital's preanaesthetic assessment form. The dental chart is to be offered as a service to anaesthetists in the form of a copyright-free "Freeware" computer diskette or adhesive sticker and will be downloadable from the internet.

Epidural abscess in an obstetric patient.

Epidural abscess is a rare complication of epidural block and occasionally presents in the post partum period. A case is described where a thoracolumbar abscess presented with backache and headache 10 days after an apparently uneventful block for labour and caesarean section. The abscess was treated medically with a satisfactory outcome. The literature is reviewed in order to assess several recent reports of infectious complications of epidural block in obstetric patients.

Clinical management of established pre-eclampsia and gestational hypertension: an anaesthetist's perspective.

Expert and aggressive pre-operative preparation of the woman with severe pre-eclampsia will ultimately determine her intraoperative outcome. Such considerations as the effect of endotracheal manipulation on intracranial pressure, of thrombocytopenia on the potential to produce a compressive epidural haematoma following epidural or combined spinal-epidural neuraxial block and of adequacy of invasive monitoring for Caesarean section loom large in the eyes of an anaesthetist preparing such a patient for surgery. Time spent pre-operatively in fluid volume optimization, in assessment of ventricular function, filling pressures and systemic vascular resistance, on aspiration pneumonitis and seizure prophylaxis, on control of hypertension, on correction of coagulopathy and on attenuation of pressor responses is time well spent and will have profound effects on the peri-operative course. The choice of agents and techniques for control of hypertension and reduction of vascular resistance, for induction and maintenance of general anaesthesia, for eclampsia prophylaxis and for regional anaesthesia or analgesia for operative or spontaneous delivery is, likewise, important and, at times, problematic.

Administration of a crystalloid fluid preload does not prevent the decrease in arterial blood pressure after induction of anaesthesia with propofol and fentanyl.

Anaesthesia was induced in 58 women (ASA I or II) undergoing elective gynaecological procedures, using propofol 2.5 mg kg-1 and fentanyl 1.5 micrograms kg-1. Patients were allocated to receive 20 ml kg-1 of crystalloid fluid preload over 20 min or to receive no fluids before induction of anaesthesia. A significant decrease in systolic arterial pressure (< 75% of baseline value) occurred in both the fluid-loaded and the control groups, and was similar in both groups. Administration of a fluid preload did not attenuate the decrease in systolic arterial pressure after induction of anaesthesia with propofol and fentanyl.

Potential intrathecal leakage of solutions injected into the epidural space following combined spinal epidural anaesthesia.

A combined spinal epidural anaesthetic (CSE), by design, produces a deliberate multicompartment block across a breached dural membrane. Since the lateral holes of the epidural catheter may lie in close proximity to the dural puncture site, a bolus solution of drug injected via the epidural catheter has the potential to leak through the dural puncture into the subarachnoid space. The aim of this study was to determine the incidence of intrathecal leak by performing an epidurogram. Fifteen patients undergoing surgery with a CSE anaesthetic using a 16 gauge Tuohy/26 gauge pencil point needle were studied. Within three hours of catheter insertion, 12 ml of contrast (iohexol 300 mg/ml) was injected via the epidural catheter under fluoroscopic control with screen recording and exposure of lateral and anteroposterior X-ray plates. All films were later reviewed for evidence of intrathecal spread. We did not observe any evidence of intrathecal spread of contrast. However, caution should be observed during administration of an intraoperative bolus dose of analgesic agent via a catheter inserted as part of a combined spinal epidural anaesthetic technique, particularly with the use of hydrophilic opiods.

Neonatal outcome and mode of delivery after epidural analgesia for labour with ropivacaine and bupivacaine: a prospective meta-analysis.

In this prospective meta-analysis, we have evaluated the effect of epidural analgesia with ropivacaine for pain in labour on neonatal outcome and mode of delivery compared with bupivacaine. In six randomized, double-blind studies, 403 labouring women, primigravidae and multiparae, received epidural analgesia with ropivacaine or bupivacaine 2.5 mg ml-1. The drugs were administered as intermittent boluses in four studies and by continuous infusion in two. Apgar scores, neurological and adaptive capacity scores (NACS), degree of motor block and mode of delivery were recorded. The studies were designed prospectively to fit meta-analysis of the pooled results. Results showed similar pain relief and consumption of the two drugs. In the vaginally delivered neonates, NACS scores were approximately equal for both groups at 2 h, but at 24 h there were fewer infants with NACS less than 35 in the ropivacaine compared with the bupivacaine group (2.8% vs 7.6%; P < 0.05). Spontaneous vaginal deliveries occurred more frequently overall with ropivacaine than with bupivacaine (58% vs 49%; P < 0.05) and instrumental deliveries (forceps and vacuum extraction) less frequently (27% vs 40%; P < 0.01), while the frequency of Caesarean section was similar between groups. The intensity of motor block was lower with ropivacaine. There were no significant differences in adverse events.

Epidural catheters for obstetrics. Terminal hole or lateral eyes?

BACKGROUND AND OBJECTIVES: Controversy exists over the choice of the ideal epidural catheter for obstetric use, particularly whether the catheter should have a single terminal hole or three lateral eyes. METHODS: A randomized single-blind study of 200 obstetric patients undergoing epidural block for analgesia in labor or for cesarean delivery was undertaken, using either a catheter with a terminal hole or three lateral eyes. The extent and quality of the block was recorded, as well as the presence of any complications. RESULTS: The study was abandoned after 102 patients had been assessed, as the incidence of unsatisfactory blocks with terminal eye catheters was found to be unacceptably high (32%), when compared with the lateral eye catheters (12%) (P < .05). Four of the terminal eye catheters (8%) had to be resited compared with one of the lateral eye catheters (2%). One case of intravascular injection (2%) occurred through a terminal eye catheter, despite repeated negative attempts at aspiration. CONCLUSIONS: The use of terminal eye epidural catheters in our obstetric patients has led to an unacceptably high incidence of both unsatisfactory blocks and catheter replacement. Lateral eye catheters produced better results in our circumstances.