Saving mothers' lives: reviewing maternal deaths to make motherhood safer: 2006-8: a review.

This review of the eighth report of the United Kingdom Enquiries into Maternal Deaths, Saving Mothers' Lives, is written primarily for anaesthetists and critical care specialists involved in both maternity and gynaecology services. Direct maternal deaths from systemic sepsis secondary to infection of the genital tract have increased. Systemic sepsis requires early recognition, immediate treatment and multidisciplinary management involving anaesthetists and critical care specialists. The incidence of deaths related to anaesthesia remains unchanged at seven in the three year period. Airway related problems unfortunately still cause maternal death. The role of early communication between obstetricians and anaesthesia and intensive care specialists is highlighted. The review summarizes the recommendations relating to anaesthesia and intensive care.

Anaesthesia chapter from Saving mothers' lives; reviewing maternal deaths to make pregnancy safer.

This chapter concerning maternal mortality due to anaesthesia, reprinted with permission from Saving Mothers' Lives, is the 18th in a series of reports within the Confidential Enquiries into Maternal and Child Health (CEMACH) in the UK. In the years 2003-05 there were six women who died from problems directly related to anaesthesia, which is the same as the 2000-02 triennium. Obesity was a factor in four of these women who died. Two of these deaths were in women in early pregnancy, who received general anaesthesia for gynaecological surgery by inexperienced anaesthetists who failed to manage the airway and ventilation adequately. When trainee anaesthetists are relatively inexperienced their consultants must know the limits of their competence and when close supervision and help may be needed. One death was due to bupivacaine toxicity due to a drug administration error when a bag of dilute local anaesthetic was thought to be intravenous fluid. In a further 31 cases poor perioperative management may have contributed to death. Obesity was again a relevant factor. Other cases could be categorized into poor recognition of women being sick and poor clinical management of haemorrhage, sepsis and of pre-eclampsia. Early warning scores of vital signs may help identify the mother who is seriously ill. Learning points are highlighted in relation to the clinical management of these obstetric complications.

Acute colonic pseudo-obstruction after caesarean section.

A 32-year-old patient developed pseudo-obstruction of the large bowel following elective caesarean section. The association of this rare postoperative complication with anaesthesia is discussed. Pseudo-obstruction of the large bowel (Ogilvie's Syndrome), is characterised by an adynamic mechanically unobstructed bowel which may progress to marked dilatation of the caecum. The reported mortality varies from 14-30% rising to 40-50% if there is caecal perforation. The underlying mechanism is thought to be an imbalance of the autonomic nervous system.

Backache and epidural analgesia: a retrospective survey of mothers 1 year after childbirth.

A questionnaire was sent to 2065 mothers 1 year after delivery as part of a larger study into patient satisfaction with all aspects of their obstetric care. The response rate adjusted for non-delivered mail was 67.1%. There was a high incidence of new long-term backache in mothers who had received epidural analgesia (26.2% at one year) compared to the mothers who had not (1.7%). Further analysis of the data revealed no other significant associated factor.

A comparison of non-invasive methods of blood pressure measurement in normotensive and hypertensive pregnant women.

We compared two types of automatic non-invasive blood pressure measuring device with sphygmomanometey in 47 normotensive and 38 hypertensive women in the third trimester of pregnancy. An automatic oscillometric device (Accutor) and a volume-clamp device (Finapres) significantly underestimated the diastolic pressure as measured by the fourth Korotkoff sound using a Hawksley random zero sphygmomanometer. The mean difference between the sphygmomanometer and Accutor measurement of diastolic blood pressure was +3.1 mmHg in the normotensive women and +8.3 mmHg in the hypertensive women (P = 0.001). The mean difference between the sphygmomanometer and Finapres measurement of diastolic blood pressure was +6.1 mmHg in the normotensive women and +11.5 mmHg in hypertensive women (P = 0.003). The increased use of continuous non-invasive devices to monitor blood pressure in women with hypertension should be accompanied by sound knowledge of their limitations in this group of patients.

Maternal deaths from anaesthesia. An extract from Why Mothers Die 2000-2002, the Confidential Enquiries into Maternal Deaths in the United Kingdom: Chapter 9: Anaesthesia.

This is the first of two extracts from Why Mothers Die 2000-2002, issued on 12 November 2004 by the Confidential enquiry into Maternal and Child Health (CEMACH), reproduced with permission. The full report can be accessed via their web site: http://www.cemach.org.uk/

Arnold-chiari malformation in pregnancy.

We report the case of a 30-year-old pregnant woman with an Arnold-Chiari malformation, who presented with severe pregnancy-induced hypertension at 30 weeks gestation. She was known to have had a difficult tracheal intubation during a previous general anaesthetic. Caesarean section was performed under an incremental epidural anaesthetic block.

Quantitative assessment of motor block in labouring women receiving epidural analgesia.

The assessment of motor block associated with epidural analgesia is traditionally performed using the modified Bromage Score. However, it is a qualitative and quantitative measurement of both spread and intensity of motor block in the lower limbs, and it has been adapted from Bromage's original use as an assessment of the adequacy of epidural anaesthesia for abdominal surgery. A number of quantitative assessment methods exist but these are either laboratory based and/or impracticable in the clinical situation of labour. We therefore set out to devise a quantitative assessment method which would be easy to use and acceptable to labouring women receiving epidural analgesia. A force transducer was modified to enable power of hip adduction to be assessed quantitatively before and after epidural analgesia was established. These results were compared with the modified Bromage Scale and an extended scale which further subdivided the scores between 0 and 1. Our results show that there is a large variation in the quantitative measurement of motor block (as measured by adductor strength) that may not be detected by the sole use of the modified Bromage Score. We suggest that future studies to assess motor block in the clinical setting use an additional quantitative method of assessment.

Pharmacokinetic and clinical study of ropivacaine and bupivacaine in women receiving extradural analgesia in labour.

We have compared, in a randomized, double-blind study, the pharmacokinetics of ropivacaine and bupivacaine during labour. Total and free plasma concentrations of ropivacaine and bupivacaine were measured after the first of two extradural doses. The main dose was 20 mg (test dose) and 30 mg, with a top-up dose of 25 mg when requested. After the main dose, Cpmax (total) of ropivacaine (0.50 mg litre-1) was similar to that of bupivacaine (0.48 mg litre-1). At 20 min, Cpmax (free) of ropivacaine (0.04 mg litre-1) was higher than that of bupivacaine (0.02 mg litre-1) (P = 0.0025). The clinical effectiveness of the block was similar in both groups.

Comparison of single, end-holed and multi-orifice extradural catheters when used for continuous infusion of local anaesthetic during labour.

Single, end-holed and multi-orifice extradural catheters were compared in terms of efficacy and complications when used for infusion of 0.1% bupivacaine during labour. In this study of 364 patients there was no difference in unilateral block after an initial bolus dose (18 (11.5%) for single, end-holed and 16 (10.9%) for multi-orifice catheters). Unilateral block recurred with seven (4.0%) single, end-holed and with eight (4.8%) multi-orifice catheters. Unilateral blocks, arising for the first time during infusion of local anaesthetic, occurred significantly more frequently when single, end-holed catheters were used (29 (16.4%)) compared with multi-orifice catheters (14 (8.4%)) (P < 0.05).

Comparison of the i.v. administration of midazolam and diazepam as sedation during spinal anaesthesia.

Midazolam hydrochloride and diazepam in emulsion were compared as i.v. sedatives for spinal anaesthesia. Mean doses of midazolam 12 mg and diazepam 27 mg were required to induce sleep and provide good or adequate sedation throughout surgery of approximately 1 h duration. Neither drug caused loss of the airway or significant cardiorespiratory changes. The frequency of drowsiness after operation was greater following sedation with diazepam, but objective testing of recovery with the Trieger test showed no significant difference between the two drugs. The frequency of amnesia was greater following midazolam.

Effect of glucose concentration on the intrathecal spread of 0.5% bupivacaine.

We have studied the effects of intrathecal injection of 0.5% bupivacaine in solutions containing different concentrations of glucose (0.33%, 0.83% and 8%) in three groups of 10 patients. The mean maximum extent of sensory block was significantly higher with 8% glucose (T3.6) than with 0.83% glucose (T7.2) or 0.33% glucose (T9.5). Administration of solutions containing 0.33% glucose produced a greater variability in upper level of sensory block (11 dermatomes) than the two other concentrations (six dermatomes each). The rate of onset of sensory block to T12 was fastest with solutions containing 8% glucose. Complete motor block of the legs was produced in every patient.

Clinical evaluation of a spinal catheter technique in femoro-popliteal graft surgery.

The use of a 24-gauge catheter for continuous spinal anaesthesia was evaluated in 20 patients undergoing femoro-popliteal graft surgery for occlusive disease. The catheter was inserted through either a Tuohy or Quincke-tip needle and isobaric amethocaine used for the initial injection. In five patients identification of the subarachnoid space was not straightforward, but clear difficulty with catheter insertion was encountered in only one. The range of blocks seen was wider than expected, but it was adequate for surgery 15 minutes after injection in 16 of the 20 patients. In another three the injection of a small dose of hyperbaric bupivacaine produced the necessary extension of block. Two patients (10%) required a general anaesthetic, one because of grossly inadequate spread of solution, the other because the catheter kinked and prevented injection of a second dose after the start of surgery.

Repeated unilateral epidural blockade.

Unilateral epidural analgesia occurring in a parturient three times in successive pregnancies is reported. Possible causes are reviewed, and clinical and radiological evidence in support of the most likely explanation are presented.

Plain bupivacaine: an unpredictable spinal anaesthetic agent.

Plain bupivacaine 0.5% or 0.75% was injected intrathecally in four groups of 10 patients. Group A received 0.75% bupivacaine 2.7 ml at L3/4, group B 0.5% bupivacaine 4 ml at L3/4, group C 0.75% bupivacaine 2.7 ml at L2/3 and group D 0.75% bupivacaine 2 ml at L3/4. A very wide range of height of block was found in each group and because of this there were few statistically significant differences between the groups. The mean height of anaesthetic blockade was significantly higher when 20 mg (group C) was injected compared with 15 mg (group D). Decreasing the volume of injection from 4 ml (group B) to 2.7 ml (group A) did not decrease this variability. By injecting at L2/3 spinal space (group C) the mean maximum level of anaesthesia (T7) was four segments higher than group A (T11) injected at L3/4, and this was reflected in a greater incidence of arterial hypotension.

Haemodynamic effects of diaspirin crosslinked haemoglobin (DCLHb) given before abdominal aortic aneurysm surgery.

We studied 34 patients undergoing elective repair of an abdominal aortic aneurysm under combined general anaesthesia and epidural block to evaluate the acute effects of diaspirin crosslinked haemoglobin (DCLHb) 50, 100 and 200 mg kg-1 i.v. Haemodynamic variables were measured continuously using pulmonary and radial artery catheters, and oxygen delivery and consumption were calculated at regular intervals. DCLHb was shown to be vasoactive, producing an increase in mean arterial pressure of approximately 25% with each dose, with small decreases in cardiac index and calculated oxygen delivery. These effects persisted beyond the end of infusion and provided a degree of cardiovascular stability during the operative procedure. The effects of DCLHb on oxygen consumption at these doses were minimal.

Comparison of ropivacaine and bupivacaine in extradural analgesia for the relief of pain in labour.

Forty women having requested extradural analgesia for labour were allocated randomly to receive 0.5% ropivacaine or bupivacaine 10 ml as the main dose. When a top-up was requested, 0.25% ropivacaine or bupivacaine 10 ml was given (the same drug as the main dose). The study ended when a second top-up was requested or delivery of the baby occurred. Pain from two contractions was assessed before extradural block by visual analogue scoring and thereafter with every contraction. Sensory block and motor block were assessed at intervals. The only significant difference between the groups was a shorter onset of pain relief after the main dose of bupivacaine; there were no other significant differences in duration, onset of pain relief after top-up, quality of analgesia, spread of sensory block and motor block between the groups. Cardiovascular changes and neonatal outcome were similar in the two groups.

Continuous subarachnoid infusion of local anaesthetic.

We observed the sensory, motor and cardiovascular changes occurring during subarachnoid infusion of bupivacaine 0.125% at 15 ml.h-1 in six patients. After 1 h, motor block and lower sensory levels were consistent and predictable but upper sensory levels were variable. There was a moderate decrease in systolic blood pressure. Regular assessments of motor block are more likely to detect accidental subarachnoid infusion than assessments of upper sensory level or measurements of blood pressure.