Nasotracheal fibreoptic intubation: a randomised controlled trial comparing the GlideRite® (Parker-Flex® Tip) nasal tracheal tube with a standard pre-rotated nasal RAE™ tracheal tube

In a randomised controlled study, we compared the ease of railroading a GlideRite® nasal tracheal tube over a fibrescope with that of a pre-rotated RAE™ nasal tracheal tube. We studied 110 anaesthetised patients with no known airway difficulties undergoing elective dental or maxillofacial surgery. Impingement was more common with the GlideRite tubes (11/55 (20%)) compared with the pre-rotated RAE tubes (3/55 (5%); p=0.02). The median (IQR [range]) time to intubation (GlideRite 7.6 (4.7-10.8 [3.0-46.2]) s; RAE 8.0 (6.2-10.7 [2.4-30.0]) s) and postoperative sore throat numerical ratings (GlideRite 2 (0-3 [0-10]); RAE 2 (0-5 [0-8])) were similar. A 90° anticlockwise pre-rotation of a standard nasal RAE tube has a higher initial rate of successful railroading at first attempt and is therefore superior to a GlideRite nasotracheal tube during nasal fibreoptic intubation.

Normal urine output after elective caesarean section: an observational study

BACKGROUND

When monitoring postoperative urine output there is no guidance specific to obstetrics. Factors such as peri-operative oxytocin infusions add further complexity. Our aim was to determine a normal range for urine output after elective caesarean section under neuraxial anaesthesia.

METHODS

Sixty women were recruited and for 24h from the time of urethral catheterisation, we recorded urine output and fluid input. We also measured intra-operative blood loss, use of prophylactic oxytocin infusion and markers of renal function. Data were compared with Mann-Whitney U-tests or paired t tests.

RESULTS

Oxytocin infusions were used in 45 women (75%). Median (95% CI) urine output in the first 6h was 0.8 (0.4-1.9) mL kg(-1)h(-1) in women receiving oxytocin compared to 1.4 (0.7-2.2)mL kg(-1)h(-1) in those who did not (P=0.02). Urine output for all women at 12 and 18 h was 2.0 (0.7-5.7) and 1.9 (0.5-4.5)mL kg(-1)h(-1). Blood loss was 0.4 (0.2-0.8)L in women with oxytocin infusions and 0.3 (0.1-0.4)L in those without (P=0.003). Mean (SD) pre- and postoperative urine osmolality was 622.5 (185.7) and 293.0 (135.1) mosm/kg, respectively (P<0.0001).

CONCLUSIONS

Urine output varied widely between subjects, especially after the first 6h and was further reduced by the use of oxytocin infusion. This may have been a direct effect or related to increased blood loss in this group. Oxytocin use should be accounted for when setting a minimum postoperative urine output. We also found high pre-operative urine osmolalities suggesting significant dehydration.

Forces required to remove bougies from tracheal tubes

Following a critical incident on our labour ward, we investigated the forces required to remove different bougies from different tracheal tubes and the effect of lubrication on ease of removal. Two studies were conducted: firstly examining the differences between six different bougies with a standard tracheal tube, and secondly examining the differences between four different tracheal tubes with a standard bougie. The forces varied amongst both the different bougies (p < 0.0001) and the different tracheal tubes (p < 0.0001). Removal was generally easier with lubrication but when corrected for multiple comparisons this did not reach statistical significance.

Outreach in obstetric critical care

The present chapter considers the evolving role of critical care outreach in the general hospital setting and applied to obstetric patients, the mechanics of transferring critically ill obstetric patients to critical care and radiology areas, the scoring systems in use in critical care, and the difficulties in applying these scoring systems to obstetric patients.

Detection of inner tube defects in co-axial circle and Bain breathing systems: a comparison of occlusion and Pethick tests

The performance of the occlusion and Pethick tests in detecting faulty inner tubes in co-axial circle and Bain systems was compared. Twelve co-axial circle and 12 Bain anaesthetic breathing systems were tested using the occlusion and the Pethick tests. For each system, three tubes were intact, and the remaining nine had a defect deliberately created in the inner tube (three proximal, three middle and three distal). The investigators were blinded to which of the tubes were defective, and to each other's results. The results showed 100% specificity for both tests. The sensitivity of the occlusion test for detecting faulty breathing systems was found to be good (98%). Our results suggest that the occlusion test should be performed in preference to the Pethick test when testing co-axial circle and Bain systems.

Cell salvage in obstetrics

The safety of cell salvage in obstetrics has been questioned because of the presumed risk of precipitating amniotic fluid embolism and, to a lesser extent, maternal alloimmunisation. For these reasons, experience in this field is limited and has lagged far behind that in other surgical specialties. There has, however, been renewed interest in its use over recent years, mainly as a result of problems associated with allogeneic blood transfusion. Our aim was to review the medical literature to ascertain the principles of cell salvage, the ability of the process to remove contaminants, and its safety profile in the obstetric setting. The search engines PubMed and Google Scholar were used and relevant articles and websites hand searched for further references. Existing cell salvage systems differ in their ability to clear contaminants and all require the addition of a leucocyte depletion filter. Although large prospective trials of cell salvage with autotransfusion in obstetrics are lacking, to date, no single serious complication leading to poor maternal outcome has been directly attributed to its use. Cell salvage in obstetrics has been endorsed by several bodies based on current evidence. Current evidence supports the use of cell salvage in obstetrics, which is likely to become increasingly commonplace, but more data are required concerning its clinical use.

Epidural lidocaine-bicarbonate-adrenaline vs levobupivacaine for emergency Caesarean section: a randomised controlled trial

Epidural mixtures containing lidocaine with or without additives are commonly used to convert epidural analgesia in labour to anaesthesia for emergency Caesarean section, but direct comparisons with alternative, single agents in this situation are few. In a prospective double-blinded trial, we compared a freshly prepared lidocaine-bicarbonate-adrenaline mixture (final concentrations 1.8%, 0.76% and 1:200,000, respectively) with our standard agent, levobupivacaine 0.5%, for extending epidural blockade for emergency Caesarean section. Using a sequential analysis technique, with data analysed in blocks of 40, women receiving epidural analgesia in labour who required top-up for Caesarean section were randomly assigned to receive 20 ml of epidural solution over 3 min. The first analysis (n = 40) indicated that the study should be stopped, as significant differences were found in our primary outcome data. Median (IQR [range]) times to reach a block to touch to T5 and cold to T4 were, respectively, 7 (6-9 [5-17]) min and 7 (5-8 [4-17]) min for lidocaine-bicarbonate-adrenaline, and 14 (10 -17 [9-31]) min and 11 (9-14 [6-30]) min for levobupivacaine (p = 0.00004 and 0.001, respectively). Pre- and intra-operative supplementation/pain, maternal side-effects and neonatal outcomes (excluding five women who underwent instrumental delivery) were similar between the groups. Intra-operative maternal sedation (scored by the mother on a 10-point scale) was greater with lidocaine-bicarbonate-adrenaline (4.5 (3-8 [1-9])) than with levobupivacaine (3 (1-4 [1-7])), but not significantly so (p = 0.07). We conclude that epidural lidocaine-bicarbonate-adrenaline halves the onset time when extending epidural analgesia for Caesarean section although there is a possibility of increased maternal sedation.