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Methoxyflurane As an Obstetric Analgesic: a Comparison with on 26 September 2021 by Guest 1554 24 December 1966 Working-time in General Practice-Eimerl and Pearson BREDICALTJSH, A Logan, R. F. L., and Eimerl, T. S. (1965). Millbank memn. Fd Quart., Peterson, 0. L., Andrews, L. T., Spain, R. F., and Greenberg, B. G. 43, No. 2, Pt. 2, pp. 302-310. (1956). 7. med. Educ., 31, No. 12, Pi. 2. pp. 1-165. Br Med J: first published as 10.1136/bmj.2.5529.1554 on 24 December 1966. Downloaded from Logan, W. P. D., and Cushion, A. A. (1958). G.R.O. Stud. on Med. and Querido, A. (1963). The Efficiency of Medical Cjie. Stenfert-Kroese. Pop. Sub;. No. 14, vol. 1, Morbidity Statistics from General Leiden. Practice. H.M.S.O., London. van der Wielen, V. (1960). M.D. Thesis: " The General Practitioner M\inistry of Healch (1965). Annual Report for 1964. H.M.S.O., London. and the Effectiveness of his Share in the Care of Health." Leiden. Appendix I nsiructions There is a separate form for each day ; please note the day Day of Week in the marked space on both sides of each form. Please note in the appropriate " box " the times of starting and of finishing a consulting session, round of visits, a particular visit-for VISITS example, night call, other work. To indicate number of patients seen during a session please mark the numerals (1-50 for that From K] to session) as each patient consults ; follow the same procedure for home visits. From L ] to Li Day of W CONSULTING-ROOM From L to [ Morning Afternoon Evening From Li to 1 26 f 1 26 1 26 2 27 L- 2 27 2 27 Time of 3 28 Time of 3 28 Time of 3 28 1 11 21 starting 4 29 starring 4 29 starting 4 29 2 12 22 5 30 5 30 5 30 3 13 23 6 31 6 31 6 31 4 14 24 7 32 7 32 7 32 5 15 25 8 33 8 33 8 33 6 16 26 9 34 9 34 9 34 7 17 27 10 35 10 35 10 35 8 18 28 11 36 11 36 11 36 9 19 29 12 37 12 37 12 37 10 20 30 13 38 13 38 13 38 14 39 14 39 14 39 HOSPITAL OR OTHER SESSIONS 15 40 15 40 15 40 16 41 16 41 16 41 17 42 17 42 17 42 From L to L 18 43 18 43 18 43 19 44 19 44 19 44 20 45 20 45 20 45 From Li to L 21 46 21 46 21 46 22 47 22 47 22 47 OTHER PROFESSIONAL DUTIES 23 48 23 48 23 48 Total time spent on other professional duties (other than that W I 24 49 fl 24 49 24 49 included above), e.g. telephoning, correspondence, contact with 25 50 L.-i25 50 j 25 50 other health workers. Time of Time of Time of finishing finishing finishing minutes http://www.bmj.com/ Side I of Appendix. Side 2 of Appendix. Methoxyflurane as an Obstetric Analgesic: a Comparison with on 26 September 2021 by guest. Protected copyright. Trichloroethylene VALERIE MAJOR,*t F.F.A. R.C.S.; AM. ROSEN, B F.F.A. R.C.S.; WILLIAM W. MUSHIN,* F.F.A. R.C.S. Brit. med. J., 1966, 2, 1554-1561 The search for new methods and drugs to provide relief of addition to these methods or as the sole means of providing pain in childbirth continues. From the large number of new pain relief. Inhalational agents fulfil a particular role because techniques advocated (Lamaze, 195S ; Bullough, 1959 ; Heyns, of their evanescent effects and because they can be self- 1959; Cahal et al., 1961 ; Hingson et al., 1961 ; Davidson, administered. 1962 ; Crawford, 1963) it is clear that none is ideal and there The two inhalational agents widely used, nitrous oxide and is yet room for improvement. Some methods, such as psycho- trichloroethylene, are of great value, though both possess certain prophylaxis, depend on adequate preparation in the antenatal disadvantages. Since this is so, any new inhalational agent period; others, such as caudal block, require the facilities of a deserves to be examined as a possible improvement. Preliminary hospital and the presence of a specially skilled doctor during clinical reports (Boisvert and Hudon, 1962 ; Romagnoli and labour-conditions which are unlikely to be fulfilled on all Korman, 1962; Johnstone, 1963) suggest that methoxyflurane occasions. Analgesic drugs are still widely used, either in is a useful and safe obstetric analgesic, though these reports do not show whether methoxyflurane has any advantage over the * Department of Anaesthetics, Welsh National Schoo! of Medicine, established agents. Our own trial was therefore designed to Cardiff. t Abbott Research Fellow. compare methoxyflurane with trichloroethylene. Trichloro- BRITISH 24 December 1966 Methoxyflurane-Major et al. MEDICAL JOURNAL 1555 ethylene was chosen because it is an already familiar analgesic, with constant flows of 8 litres per minute or more there was with physical characteristics somewhat similar to those of negligible lag between a change in the vaporizer setting and Br Med J: first published as 10.1136/bmj.2.5529.1554 on 24 December 1966. Downloaded from methoxyflurane. the change in the inhaled concentration. All concentrations given in this paper refer to actual inhaled concentrations and Administration of the Drugs not to vaporizer-scale settings. As well as adjusting the concentration of the vapour the A trial of a new drug usually requires two steps: the anaesthetist made continuous clinical observations and assess- optimum dose of the drug is determined, and then its effects ments, which were recorded immediately on a tape recorder. are compared with those of some other known drug. A com- parison between inhalational agents administered intermittently in fixed concentrations presents a particular problem. The Assessment dose the patient receives depends not only on the inspired con- centration but also very largely on what fraction the inter- The effects of the drugs were separately assessed by the mittent periods form of the whole duration of the inhalation. anaesthetist, by the midwife, and by the mother. These factors have made it necessary in previous trials to study large numbers of patients in order to obtain reliable results. We administered methoxyflurane and trichloroethylene con- Observations by Anaesthetist tinuously to avoid the difficulty presented by differences in the If an analgesic is to prove satisfactory, not only to the mother duration of intermittent inhalations. This method also enabled but also to the midwife and to the doctor, then other factors us to carry out two steps of the investigation simultaneously besides pain relief must be studied. They include the mother's in the following manner. The concentration of both vapours motor and emotional response to contractions, her motor and was varied according to the judgement of an experienced emotional reactivity between contractions, and her general level anaesthetist, with the aim of giving each patient the maximum of consciousness. These three factors provide the ingredients analgesia possible without causing undesirable side-effects. The of "good " analgesia. Each of them was separately and con- concentrations necessary to maintain this state must have been tinuously assessed by the anaesthetist throughout the period of those which were optimum for each patient. From a knowledge inhalation. The grading used for each was chosen during a of these concentrations the concentration likely to be suitable preliminary trial. All the assessments included in the results for intermittent inhalation might be predicted. This method were made by one anaesthetist. In practice it was not difficult also provides a basis for the comparison between the drugs, to choose a grade ; two of us scored some patients independently because it produces the most favourable response for each drug with complete agreement. These grades were further and therefore provides the highest number of satisfactory results grouped into "satisfactory " and "unsatisfactory "-terms which are in each of the groups. precisely defined below. Since the assessment of new analgesics is always difficult, and 1. Mother's Response to Contractions.-This provided objective the are results in obstetrics greatly influenced by the environ- evidence of the mother's behaviour during a contraction, and gives ment, antenatal care, and the personality of both mother and some indication of the pain felt. The grades used were: attendants, the drugs were compared under identical circum- stances. No response: lies quietly and shows no, The patients were divided into two groups by previously distress. These were regarded Slight response : grimaces, clenches her as satisfactory. randomizing the days for which each drug was used. The fists, or moves slightly on the bed.) http://www.bmj.com/ trial was carried out in two hospitals, each with several labour larked response: groans, cries out, or rooms; many midwives were involved, making it difficult for them to identify the pattern of the experiment. Inhalation moves marKedly. These were regarded Uncontrolled response: cries, tosses as unsatisfactory. was started at the midwife's request, usually towards the end about, and is uncontrollable during of the first stage of labour. The patients in the trial were a contraction. chosen by the midwives but did not include any who had 2. Level of Consciousness.-This was graded as: attended classes in psychoprophylaxis or hypnosis. In addition Alert: eyes open, looks around, or holdsA the midwives tended to reserve the straightforward cases for a spontaneous conversation. teaching their pupils about inhalational analgesia. For these on 26 September 2021 by guest. Protected copyright. but when rerde Drowsy: lies quietly responds aThese reasons a cases high proportion of unbooked and difficult spoken to, talks with a normal voice, as satisfactory.
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