Anaesthesia for Caesarean section. The potential for regional block

Similar onset time of 2-chloroprocaine and lidocaine + epinephrine for epidural anesthesia for elective Cesarean section

BACKGROUND

The use of regional anesthesia for elective Cesarean section has been demonstrated to be safe for both the mother and new-born. In parturients with an epidural catheter placed previously for labor analgesia, extension of the epidural block may be the preferred option, provided that adequate speed of onset and adequate surgical anesthesia are obtained. We therefore performed a prospective, randomized, double-blind trial to examine the speed of onset and anesthetic quality of 2-chloroprocaine vs. a solution of lidocaine with one additive, epinephrine 5 microg/ml.

METHODS

Forty ASA I patients, scheduled for elective Cesarean section, were randomly assigned to two groups: the 2-chloroprocaine group received 2-chloroprocaine 30 mg/ml and the lidocaine group received the same amount (ml) of lidocaine 20 mg/ml with 5 microg/ml epinephrine. The speed of onset was defined as the time taken to loss of cold sensation from 70% ethanol application at thoracic dermatome level 5 (Th5).

RESULTS

The time to achieve loss of cold sensation at Th5 was similar in both groups: median of 8 min (range, 4-13 min) in the 2-chloroprocaine group vs. 5 min (range, 2-22 min) in the lidocaine group (NS). Epidural anesthesia was successful for surgery in all but one patient (lidocaine group). There was no significant difference in the need for supplemental intravenous alfentanil between the two groups: 30% vs. 20% of patients in the 2-chloroprocaine and lidocaine groups, respectively; the pain scores (visual analog scale) were also similar. Intra-operative complications occurred with similar frequency, and none was serious. In the patients in the 2-chloroprocaine group, 11 (55%) had episodes of systolic blood pressure less than 90 mmHg vs. 15 (75%) in the lidocaine group (NS).

CONCLUSION

Both 2-chloroprocaine and lidocaine have a rapid onset of effect and are suitable local anesthetic agents for Cesarean section. In view of the time taken for preparation and the potential for logistic problems when an additive is used, a pre-prepared solution, such as 2-chloroprocaine, may be preferred.

A survey of anaesthetic techniques used for caesarean section in the UK in 1997

A prospective survey of anaesthesia for caesarean section was performed for the year 1 January to 31 December, 1997. Two hundred and fifty maternity hospitals were sent questionnaires from which 129 responses were obtained. The data provided information on anaesthesia for 60 455 caesarean sections. Overall 78% of sections were performed with regional anaesthesia: 47% single shot spinal; 22% epidural; 9% combined spinal epidural (CSE); 22% general anaesthesia. For elective caesarean sections (39% of all sections) regional anaesthesia was used for 87% of cases: 68% single shot spinal; 3% epidural; 15% CSE; 13% general anaesthesia. For emergency procedures regional anaesthesia was used for 72% of cases: 34% single shot spinal; 34% epidural; 4% CSE; 28% general anaesthesia. There was a wide range of regional anaesthesia use among the units, varying from an overall rate of 95% at one extreme to 41% at the other. Similarly, there was a wide range of conversion of regional anaesthesia to general anaesthesia, varying from 0% to 88%. Overall, 10.6% of the general anaesthetics were the result of regional to general anaesthesia conversion.

Anaesthesia for caesarean section--a German survey

BACKGROUND

Anaesthetic practice for caesarean section has changed during the last decades. There is a world-wide shift in obstetric anaesthetic practice in favour of regional anaesthesia. Current data concerning anaesthetic practice in patients undergoing caesarean section from Germany are not available. A comparison with figures from the UK, USA, Norway and other European countries might be of general interest.

METHODS

Questionnaires on the practice of anaesthesia for caesarean section and anaesthetic coverage of the obstetric units were sent to 1178 university, tertiary care, district, community and private hospitals in Germany.

RESULTS

The 532 completed replies of this survey represent 46.9% of the German obstetric units. Most hospitals (42.3%) have delivery rates between 500 and 1000 per year. General anaesthesia is the most common anaesthetic technique for elective (61%), urgent (83%) and emergency caesarean section (98%). Epidural anaesthesia is performed in 23% of scheduled and 5% of non-scheduled caesarean sections, and spinal anaesthesia in 14% and 10% respectively. Acid aspiration prophylaxis before elective caesarean section is used in 68.7% of the departments. The majority of the departments provide a 24-hour anaesthetic coverage; however, in only 6.2% of the units, this service is assigned to obstetric anaesthesia, exclusively.

CONCLUSION

Compared to data from 1978, anaesthetic practice for caesarean section has changed with an increase in regional anaesthesia. However, German anaesthetists prefer general anaesthesia for caesarean section. In contrast, anaesthetists in other countries predominantly use regional techniques, and the difference to German practice is striking. International consensus discussion and recommendations as well as comparable European instruments of quality control in obstetric anaesthesia are desirable.

Extending epidural blockade for emergency caesarean section Evaluation of 2% lignocaine with adrenaline

Pre-existing epidural analgesia was rapidly extended in 36 consecutive patients presenting for emergency caesarean section by using 20 ml of 2% lignocaine + 1/200,000 adrenaline freshly prepared given by slow bolus injection. Despite a wide range of initial analgesic sensory levels the technique produced blocks that were dense with adequate anaesthesia for surgery in all patients within 12.5 min. The plasma local anaesthetic concentrations were well below the toxic range. Neonatal condition was good.

Anaesthesia for emergency caesarean section

The Report on Confidential Enquiries into Maternal Deaths in England and Wales 1982-84 (Department of Health 1989) recommends early involvement of the anaesthetist in women having emergency caesarean sections and the use of epidural anaesthesia in preference to general anaesthesia. In an observational prospective study the need for emergency abdominal delivery could be anticipated in 87% of 360 consecutive emergency caesarean sections. Early establishment of epidural analgesia allowed extension, to an appropriate level for the surgery, in 70%. The duty anaesthetist accompanying the obstetric team on three wardrounds a day could be forewarned of anticipated problems in most women who are eventually delivered abdominally.

Epidural versus general anaesthesia for elective caesarean section. Effect on Apgar score and acid-base status of the newborn

Elective Caesarean section deliveries over a 5-year period were studied to compare the effect of epidural block with general anaesthesia on the condition of the infant at birth. The Apgar score and umbilical arterial acid-base status were used as determinants of the latter. Epidural block was used in 139 (22.8%) mothers while 471 (77.2%) were performed under general anaesthesia. No babies in the epidural group were severely depressed (Apgar less than 4), compared with 6.2% in the general anaesthesia group. Only 4.3% of the epidural sections were moderately depressed (Apgar 4-6), compared with 15.4% of the others. These differences remained highly significant when infants of less than 2500 g were excluded, and when matched groups were compared. Mean umbilical arterial pH was similar within the two groups (pH 7.28), and was not consistent with asphyxia in almost 90% of the depressed infants. The findings suggest that general anaesthesia, rather than asphyxia or aortocaval compression, is responsible for most of the depressed infants born by elective Caesarean section. This may involve over 20% of babies delivered in this manner, so greater use of epidural block for elective Caesarean section is recommended. Further investigations are required to improve results with general anaesthesia.

Obstetric epidural test doses. A reappraisal

A number of obstetric fatalities related to epidural anaesthesia have been reported recently. In each case catheter or needle misplacement had resulted in a lethal intrathecal or intravascular injection. In this review these cases and a number of other similar but nonfatal reports are examined. In many cases, essential safety checks such as the aspiration test and the test dose had not been performed before the epidural injection but in others one or both of these tests had been used and had failed to predict the complication. Safety test failures generally occurred because ineffective tests were used or because effective tests were inadequately interpreted. This is not surprising because although textbooks recommend a bewildering variety of test doses, they seldom give precise details as to how they should be conducted. A detailed test dose protocol is recommended, which will safely warn of epidural catheter and needle misplacement in the most effective manner possible. If the protocol is used, accidental subarachnoid and intravascular injections can be reduced to a minimum, but they will still occur. It is emphasised that these complications should not cause fatalities if trained personnel and adequate resuscitation facilities are available.

Neonatal advantage of epidural anesthesia in elective and emergency cesarean sections: a report of 531 cases

In 147 elective and 384 non-elective cesarean sections, the need for neonatal respiratory assistance at birth was significantly greater for babies born under general anesthesia compared to epidural anesthesia, and the differences could not be explained by differences in pre-operative risk factors. For 114 babies on whom blood gas data were gathered prospectively, a greater proportion born under general anesthesia were acidemic and hypercarbic. Our results complement a growing body of retrospective and clinical data suggesting that epidural anesthesia is preferable to general in all but a few cesarean sections. Ideally, this suggestion should be tested in a randomized clinical trial.

Anaesthetic morbidity following caesarean section under epidural or general anaesthesia

To find out whether morbidity in the first postoperative week is affected by type of anaesthetic technique, healthy patients who had caesarean sections under epidural anaesthesia were compared with those who were given a general anaesthetic. Epidural anaesthesia was associated with less pain (p less than 0.00001) and discomfort in the immediate postoperative period. By the second day fewer epidural patients had gastrointestinal stasis, pyrexia (p less than 0.05), and coughing (p less than 0.00001). Breastfeeding and mobilisation started earlier. Fewer mothers were coughing (p less than 0.005), had fever (p less than 0.01), or felt tired and depressed (p less than 0.005) by the sixth postoperative day after epidural caesarean section. The epidemiology of anaesthetic morbidity needs to be assessed in other surgical patients.