British Journal of Anaesthesia 1996;77:550–552 Extradural anaesthesia for Caesarean section in a patient with moyamoya disease W. D. NGAN KEE AND C. D. GOMERSALL Summary We report a case of moyamoya disease in a patient presenting for Caesarean section at 37 weeks’ gestation. Extradural anaesthesia was administered using 0.5% bupivacaine and pethidine 25 mg. A stable haemodynamic state was produced using left lateral uterine displacement, i.v. crystalloids and an i.v. infusion of ephedrine. The patient suffered no neurological deficit and there was no significant intraoperative decrease in cerebral oxygenation measured by near infrared spectroscopy. (Br. J. Anaesth. 1996;77:550– 552) Key words Anaesthesia, obstetric. Anaesthetic techniques, extradural. Complications, moyamoya disease. Moyamoya disease is a rare occlusive disease of the large intracranial arteries. Patients are at risk of cerebral ischaemia and haemorrhage, and neurological deterioration may occur during pregnancy. Delivery by Caesarean section has been recommended but the optimal anaesthetic technique is not known and monitoring of cerebral perfusion or oxygenation during anaesthesia has not been described. We report the use of extradural anaesthesia in a term parturient with moyamoya disease, with continuous monitoring of cerebral oxygenation by near infrared spectroscopy. Case Report The patient, a 36-yr-old, para-1, gravida-4 woman, was admitted at 28 weeks’ gestation for observation with a plan for elective Caesarean delivery at 37 weeks’ gestation. She had been diagnosed angiographically to have moyamoya disease 4 yr previously after a spontaneous left temporal intracerebral haematoma. Treatment had been conservative and she had made a good recovery with a residual right visual field defect but no other neurological deficit. She had had one normal delivery 13 yr previously. On this admission, there were no abnormal neurological findings other than the visual field defect. Arterial pressure was in the range 100–120/ 60–80 mm Hg. We planned extradural anaesthesia with invasive haemodynamic monitoring and continuous measurement of cerebral oxygenation by near infrared spectroscopy (NIRS). The patient remained well for the remainder of the pregnancy, but went into spontaneous labour 4 days before the date of planned surgery and was scheduled to the emergency operating list. She was premedicated with ranitidine 50 mg i.v. and 0.3 mol litre91 sodium citrate 30 ml orally. On arrival in the labour ward, her cervix was 5 cm dilated and pethidine 100 mg i.m. was given for analgesia by the obstetric team. Standard monitoring was applied and 35% oxygen was given by face mask. A radial artery cannula and central venous catheter (via the antecubital fossa) were inserted. Intrathoracic placement of the central venous catheter was confirmed by observation of fluctuations in central venous pressure with respiration. Bifrontal regional cerebral oxygen saturation was measured continuously by NIRS using the Invos 3100 (Somanetics Corp., Troy, MI, USA) and NIRO 500 (Hamamatsu Photonics KK, Hamamatsu City, Japan) (fig. 1). Unfortunately, because the time of operation out of normal hours, there was a delay in preparing the equipment and recordings could only be started after commencement of anaesthesia. After i.v. preload with lactated Ringer’s solution 1000 ml, an extradural catheter was placed in the L2–3 interspace with the patient in the lateral position. She was then turned supine with left lateral tilt. Incremental injections of 3 ml of 0.5% bupivacaine (plain) were given at 4–5-min intervals, followed by pethidine 25 mg via the extradural catheter. I.v. infusion of ephedrine 100–500 ␮g min91 was titrated throughout the anaesthetic to maintain arterial pressure as near as possible to preoperative values. After 27 ml of bupivacaine, the level of sensory analgesia to pinprick was T6 and surgery was started. A healthy 2.61-kg male infant was delivered with Apgar scores of 9 (1 min) and 10 (5 min). Arterial umbilical cord blood gas tensions were pH 7.294, PCO2, 6.6 kPa and PO2 1.6 kPa, and venous umbilical cord blood gas tensions were pH 7.297, PCO2 6.6 kPa and PO2 1.8 kPa. Oxytocin 10 u. was given i.v. over 15 min after delivery. Blood loss was approximately 300 ml. A total of 1500 ml of lactated Ringer’s solution was given in the perioperative period. To maintain normothermia, all i.v. fluids were warmed, the operating theatre temperature was increased to 22 ⬚C and the patient’s upper body was covered with blankets. Continuous temperature monitoring was not available because of technical problems, but the patient’s sublingual temperature measured by mercury ther- WARWICK D. NGAN KEE, FANZCA, CHARLES D. GOMERSALL, FRCA, Department of Anaesthesia and Intensive Care, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong. Accepted for publication: May 24, 1996. Extradural anaesthesia in moyamoya disease Figure 1 551 Invos 3100 and NIRO 500 near infrared cerebral oximeters in place on a model. mometer at the end of the procedure was 36.7 ⬚C. Verbal contact was maintained throughout and bilateral hand grip was checked intermittently. The intraoperative record of arterial pressure, heart rate and cerebral oxygenation is shown in fig. 2. Slight decreases in arterial pressure occurred after establishment of extradural block and after delivery, the latter episode coinciding with administration of oxytocin, but this was not associated with changes in mental state or hand grip and no significant concurrent change in cerebral oxygenation was detected by either spectrometer. A slight increase in deoxyhaemoglobin concentration occurred shortly after skin incision which was matched by an increase in total haemoglobin concentration and no change in cytochrome oxidase redox state. After operation, the patient was observed in the high dependency area of the labour ward for 24 h where oxygen, pulse oximetry and direct arterial pressure and ECG monitoring were continued. Analgesia was provided by patient-controlled extradural analgesia using pethidine 10 mg ml91 (bolus 20 mg, lockout 10 min). Subsequent progress was uneventful with no new neurological signs and no respiratory depression. The patient was discharged 4 days after delivery. ischaemia4. However, there are risks of difficult tracheal intubation, aspiration of stomach contents and neonatal depression. The hypertensive response to intubation may precipitate intracerebral haemorrhage and although this response may be obtunded by the use of adjuvant drugs such as vasodilators, sympathomimetic antagonists and rapidly acting opioids, care must be taken to avoid hypotension and Discussion Moyamoya disease is a rare disease named after the Japanese word describing the characteristic “puff of smoke” appearance that is seen on cerebral angiography. It has most often been reported in the Japanese, is more common in children and females and there may be a familial predisposition1. Elective Caesarean section has been recommended for the pregnant patient with moyamoya disease to avoid possible deleterious effects of pain, hyperventilation and bearing-down during labour2. Although the principles of anaesthesia in moyamoya disease have been described previously1, the optimal technique during pregnancy is unknown. General anaesthesia has been used3 and has the potential advantages of decreasing the cerebral metabolic rate for oxygen which may confer some protection against Figure 2 Intraoperative recordings of mean arterial pressure (MAP) (!) and heart rate (HR) (!) (top), regional cerebral haemoglobin (Hb) saturation measured by the Invos 3100 (middle) and changes in oxyhaemoglobin (▲), total haemoglobin (●), deoxyhaemoglobin (䉭) and cytochrome oxidase redox state (!) measured by the NIRO 500 (bottom). 552 consequent cerebral ischaemia. Hypocapnia may cause neurological deficit5 so use of capnography during controlled ventilation is mandatory. Regional anaesthesia avoids these risks but the associated sympathetic block may lower cerebral perfusion pressure causing ischaemia distal to the stenotic vessels. Spinal anaesthesia was associated with convulsions and hemiparesis in a child6. Sharma and colleagues7 used extradural anaesthesia for Caesarean section in a parturient at 31 weeks’ gestation and reported advantages that included continuous monitoring of conscious level and cerebral function in an awake patient. They emphasized the need to avoid hypotension but relied solely on crystalloid preload and uterine displacement to negate the effects of sympathetic block and did not provide details of haemodynamic changes. Because the parturient at term is particularly susceptible to hypotension during extradural anaesthesia8 more active management may be necessary to maintain cerebral perfusion. However, large upward swings in arterial pressure should also be avoided because of the potential for intracerebral haemorrhage. In our patient we found, using an infusion of ephedrine in addition to fluids and lateral tilt, arterial pressure was well maintained without marked fluctuations. The absence of signs of cerebral insufficiency in our awake patient in the intraoperative period and the absence of a neurological deficit after operation make it unlikely that significant cerebral ischaemia occurred. However, in the presence of extradural block, signs of transient ischaemia in the anterior cerebral territory may be masked. Anterior cerebral artery occlusion, in the absence of the inconstant recurrent artery of Heubner, leads to flaccid paralysis and cortical sensory loss in the legs, incontinence of urine, and intellectual and memory deficit9. However, the level of block required for Caesarean section precludes assessment of neurological function of the legs and bladder. Therefore, we used NIRS to confirm adequacy of oxygenation in the anterior cerebral artery territory. NIRS uses spectral analysis of reflected infrared light to measure cerebral oxygenation10. It has been used to assess cerebral haemoglobin oxygen saturation in both adults11 and neonates12, and has been described as a monitor of cerebral oxygenation during carotid endarterectomy13. The Invos 3100 gives an absolute value of regional haemoglobin saturation while the NIRO 500 displays changes in regional oxyhaemoglobin, deoxyhaemoglobin, total haemoglobin and cytochrome oxidase redox state. Both monitors are simply and non-invasively applied using probes attached to the patient’s forehead. As the maximal distance that can be penetrated by infrared spectrometers is approximately 8 cm14, the regions of the brain monitored in our patient would have been predominantly within the territory of the anterior cerebral arteries. Although there was a slight British Journal of Anaesthesia increase in deoxyhaemoglobin concentration after skin incision, the concurrent increase in total haemoglobin concentration suggests that any decrease in cerebral oxygenation was likely to be minimal and the absence of a change in cytochrome oxidase redox state shows this did not lead to a change in oxygen delivery at a cellular level. A disadvantage of using near infrared spectroscopy in emergency surgery is the time required to prepare the equipment: approximately 30 min was required for the lasers of the NIRO 500 to warm up to operating temperature which precluded measurement of cerebral oxygenation before the start of anaesthesia. Acknowledgement Purchase of the Hamamatsu NIRO 500 was partially funded by a grant from the University and Polytechnics Grant Committee, Hong Kong. References 1. Brown SC, Lam AM. Moyamoya disease—a review of clinical experience and anaesthetic management. Canadian Journal of Anaesthesia 1987; 34: 71–75. 2. Miyakawa I, Lee HC, Haruyama Y, Mori N, Mikura T, Kinoshita K. Occlusive disease of the internal carotid arteries with vascular collaterals (moyamoya disease) in pregnancy. Archives of Gynecology 1986; 237: 175–180. 3. Venkatesh B, Taggart PCM. Anaesthetic management of a patient with Moyamoya disease for Caesarean section. Canadian Journal of Anaesthesia 1994; 41: 79–80. 4. Smith AL, Wollman H. Cerebral blood flow and metabolism: effects of anesthetic drugs and techniques. Anesthesiology 1972; 36: 378–400. 5. Sumikawa K, Nagai H. Moyamoya disease and anesthesia. Anesthesiology 1983; 58: 204–205. 6. Yasukawa K, Akagawa S, Nakagawa Y, Miyasaka K. Convulsions and temporary hemiparesis following spinal anesthesia in a child with moyamoya disease. Anesthesiology 1988; 69: 1023. 7. Sharma SK, Wallace DH, Gajraj NM, Willis C, Sidawi E. Epidural anesthesia for a patient with moyamoya disease presenting for cesarean section. Anesthesia and Analgesia 1994; 79: 183–185. 8. Wright RG, Shnider SM. Hypotension and regional anesthesia in obstetrics. In: Shnider SM, Levinson G, eds. Anesthesia for Obstetrics. Baltimore: Williams and Wilkins, 1993; 397–406. 9. Patten J. Neurological Differential Diagnosis. London: Harold Starke, 1977; 86–98. 10. Harris DNF. Near infra–red spectroscopy. Anaesthesia 1995; 50: 1015–1016. 11. Hampson NB, Camporesi EM, Stolp BW, Moon RE, Shook JE, Griebel JA, Piantadosi CA. Cerebral oxygen availability by NIR spectroscopy during transient hypoxia in humans. Journal of Applied Physiology 1990; 69: 907–913. 12. Wyatt JS. Noninvasive assessment of cerebral oxidative metabolism in the human newborn. Journal of the Royal College of Physicians of London 1994; 28: 126–132. 13. Duncan LA, Ruckley CV, Wildsmith JAW. Cerebral oximetry: a useful monitor during carotid artery surgery. Anaesthesia 1995; 50: 1041–1045. 14. Burcher HU. Detection of cellular hypoxia by monitoring cytochrome oxidase with near infrared spectrophotometry. In: Ehrly AM, Fleckenstein W, Landgraf M, eds. Clinical Oxygen Pressure Measurement III. Berlin: Blackwell Wissenschaft, 1992; 15–24.