Subarachnoid anaesthesia for Caesarean section

Abstract

We read with interest the report by A.R. Michie e f nl. (ilnnesrhesia 1988; 43: 9 6 9 ) . Subarachnoid anaesthesia has been used recently in our hospital for Caesarean sections with very satisfactory results. Our practice differs from that of the authors in several respects. We preload our patients with 500 ml compound sodium lactate solution and 500 ml modified gelatin (Gelofusine) before the subarachnoid block is established. Intramuscular ephedrine 30 mg is given prophylactically 15-30 minutes before the spinal block. The patient is placed in the left lateral position and 1.5-2.0 ml 0.5% hcavy bupivacaine are injected at L, or L3-, interspace through a 26-G spinal needle, using minimal barbotage.The patient is placed supine immediately with right lateral tilt and the extent of the block assessed with ethyl chloride spray. The table is then tilted to obtain a block to T, and thc table returned to a left lateral tilt when surgery starts.This technique has been used on 40 patients with satisfactory analgesia in all cases. Hypotension (systolic 100 mmHg or symptomatic) in 23% of patients was rapidly corrected with intravenous increments of ephedrine; in two patients the hypotension was serious. Postoperative headache was minimised by taking great care to ensure that thcre was only a single puncture of the dura and keeping the patients flat for 12 hours after the Caesarean section.We considcr subarachnoid anaesthesia to have significant advantages over epidural anaesthesia for Caesarean section. in particular because of the rapid onset of action and the more profound analgesia produced. Thank you for the opportunity to reply. We are pleased that the authors have successfully used subarachnoid anaesthesia for Caesarean sections. We continue to givc crystalloid alone for preload, but in addition we add 30 mg cphcdrine to the third 500-ml bag of Ringer-lactate solution. This is started immediately after subarachnoid injection, in anticipation of hypotension rather than in response to it. We consider that using intramuscular ephedrine, as the authors suggest, may be inappropriate if there is difficulty or protracted dclay in establishing blockade.It is also pertinent to point out that in the most recent Data sheet for Gelofusine (1988). it is stated: 'Anaphylactoid reactions are exceedingly rare, but may be likely to occur if Gelofusine solution is given rapidly to normovolaemie patients, in common with other plasma substitutes. It should not be used to prevent falls in arterial pressure, consequent on spinal or epidural analgesia'.The authors' efforts to reduce the incidence of headache are admirable, but in practice it is not always possiblc to guarantee a single dural puncture in every case, especially with obese or oedematous patients. There is also great resistance from some nursing mothers, at the requirement to lie flat. even for 12 hours postoperatively. Allowing these women to sit up and feed their infants, should not substantially alter the incidence of headachc. We agree in general terms however, that subar...