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Peripartum care of parturients has contributed a great deal to the development of modern anaesthesia during the past 150 years. The introduction of general and regional anaesthesia provided new options of relieving pain during delivery and preventing suffering. However,provision of effective labor analgesia gave and still gives rise to controversy as to whether interfering with natural events such as delivery was justifiable on a religious,moral or ideological level. A new era of obstetric pain relief was initiated when a study design was devised to define the Minimum Local Analgesic Concentration (MLAC) needed for epidural analgesia. Using the MLAC model as a scientifically based pharmacodynamic measure of analgesia, empirically developed "recipes" can be compared and validated. The importance of this clinical model will be put into a pharmacological context including issues such as the up-down sequential allocation technique, dose-response curves and differential nerve blockade.

Question: This survey investigated the common practice of obstetric analgesia and anaesthesia in Swiss hospitals and evaluated the influence of the Swiss interest group for obstetric anaesthesia., Methods: In March 1999 we submitted 145 questionnaires to all Swiss hospitals providing an obstetric service., Results: The rate of epidural analgesia (EA) was higher in large hospitals (> 1,000 births/year) than in small services. EA was maintained by continuous infusion techniques in 53% of the responding hospitals. For elective caesarean section, spinal anaesthesia (SA) and EA were performed in 77% and 16% of the patients, respectively. General anaesthesia (5%) was only used in small hospitals (< 500 births/year). Emergency caesarean section was performed under SA in 75% of all hospitals and only in 25% was a general anaesthesia used. An already existing EA for labour analgesia was continued for anaesthesia for caesarean section in 63% of Swiss hospitals., Conclusions: Regional anaesthesia was most commonly used for obstetric anaesthesia in Swiss hospitals. Epidemiological studies, recommendations of the Swiss interest group for obstetric anaesthesia, as well as the expectations of pregnant women, increased the numbers of regional anaesthesia compared with the first survey in 1992.

In 1900, Oskar Kreis (1872-1958), a gynecologist and obstetrician who received his training at the Basle University Women's Hospital, pioneered the use of spinal anaesthesia in six parturients for labour pain relief. Cocaine was used as a local anaesthetic, which had previously been shown to be effective for spinal anaesthesia by August Bier in 1898. This important advance in anaesthetic care was not widely acknowledged for a long period of time and it has only been during the past few decades that spinal anaesthesia was rediscovered as an important technique available for obstetric anaesthesia.

The interactions of alpha(2)-adrenoceptor agonists with anaesthetics, analgesics and local anaesthetics are not only of practical importance in many areas of anaesthesia and pain therapy, but also of significant theoretical interest. Laboratory investigations and animal research allow us to study the pharmacological mechanisms of these drug interactions by using the tools of molecular biology. This may lead to the establishment of a scientific basis allowing the definition of rational drug therapies. In the first part of this overview, recent data on local anaesthetic effects of alpha(2)-adrenoceptor agonists on peripheral nerve conduction and their interaction with local anaesthetics are presented. Some important experimental work focusing on additive and synergistic spinal interactions of alpha(2)-adrenoceptor agonists with opioids and some other agents are then discussed. Finally, there is a brief reference to the central role of the spinal cord in mediating and controlling nociception.