Near-infrared spectroscopy in adults

Sir,—We thank Dr Sinton for his detailed comments on our case report. The combined spinal-extradural was used to provide analgesia for vaginal examination and rupture of membranes in this woman with a known low lying placenta. In our experience, this technique provides excellent sacral analgesia without motor block, which is obviously undesirable in early labour. We apologize that full details were not given; the extradural catheter was resited only after attempts to produce bilateral analgesia had failed. The second extradural catheter placement also afforded unsatisfactory analgesia and another subarachnoid block was the only alternative to a general anaesthetic for the emergency Caesarcan section. The patient had expressed a desire to remain awake during delivery. It is our practice to offer extradural blood patch early in the treatment of post-dural puncture headache if simple analgesics and non-steroidals have failed and the patient desires further treatment. Extradural blood patches have been used since 1960 [1] with a very low incidence of serious complications [2]. We do not feel that comparison of the combined spinalextradural technique with micro-spinal catheters is appropriate. Micro-spinal catheters of 27-gauge or less were withdrawn in the USA in 1992 (not the early 1980s) after 11 cases of cauda equina syndrome were reported [3, 4]. All patients have the right to fully informed consent before agreeing to any medical procedure. Our firm intention, as with all other doctors, is to do no harm to our patients.