The effect of extradural ketamine on onset time and sensory block in extradural anaesthesia with bupivacaine

Abstract

SummaryIn a randomised, double blind study of 30patients, we have compared two regimens for extradural anaesthesia: 20 ml bupiuacaine 0.5%, 25mg (0.5ml) ketamine, I in 200000adrenaline; and20ml bupivacaine 0.5%, 0.5mlO.9% saline, 1 in 200000adrenaline.The main outcome measures were onset time to acceptable bilateral anaesthesia and postoperative analgesic duration. The time to onset of anaesthesia was reduced by 8 min in the bupivacaine-ketamine group compared with the bupivacaine alone group. In addition, the anaesthetic levels were two segments higher in the bupivacaine-ketamine group (TI oersus T9). Side effects were similar in both groups and there was no significant diflerence in postoperative analgesic requirements between the two groups. The addition of ketamine to bupivacaine given epidurally appears to be useful in the reduction of onset time to blockade. Key wordsAnaesthetic techniques; extradural. Analgesics; ketamine. Anaesthetics, local; bupivacaine.Extradural block provides satisfactory anaesthesia for many orthopaedic, gynaecological and urological procedures. However, the technique has a number of disadvantages [ 11; variation in the degree of sensory, motor and sympathetic nerve blockade may lead to painful intervals, variable muscle power and cardiovascular instability. In addition, extradural anaesthesia is associated with a slow onset time [2]. Adrenaline has been shown to improve the efficacy of extradural block [3], whilst the addition of opioids to local anaesthetics administered extradurally has been shown to improve analgesia, but not significantly to reduce the onset time [2].Ketamine has well-known analgesic properties and animal experiments have shown that intrathecal administration of ketamine, with benzethonium chloride preservative, has no neurotoxic effects [4]. In some clinical studies, the extradural administration of ketamine has provided a potent and safe method for postoperative analgesia and has been proposed as an alternative to local anaesthetics and opioids [5, 61. This double-blind study was designed to compare the effects of extradural bupivacaine-adrenaline or bupivacaine-adrenaline-ketamine mixtures, on onset time of anaesthesia and the degree of sensory and motor block. MethodsThe study was approved by the local ethics committee and written informed consent was obtained from all participants. Thirty patients, ASA 1 or 2 physical status, who were to undergo elective orthopedic, urological or lower abdominal surgery were recruited. Patients were not studied if they had a history of neurological, mental and spinal diseases or had a bleeding diathesis.No premedication was given. An intravenous infusion of compound sodium lactate solution 500 ml was started prior to extradural placement. Patients were randomly allocated to one of two groups. Neither the patient, nor the anaesthetist was aware of the group allocation. Two solutions were used for extradural anaesthesia: group 1 received 20 ml bupivacaine 0.5%, 1 in 200 000 adrenaline and 0.5 ml 0.9% saline; group 2 receiv...

Effect of i.v. ketamine in combination with epidural bupivacaine or epidural morphine on postoperative pain and wound tenderness after renal surgery

“…[3][4][5] Experimental and clinical studies have demonstrated that block of the NMDA receptor before or during injury may prevent or reduce the development of central sensitization [6][7][8][9][10][11][12][13][14][15] and NMDA receptor block after injury can reduce or abolish central sensitization that has already been established. 16 Previous studies indicate that NMDA receptor antagonists potentiate the effects of other analgesics, such as morphine, [17][18][19][20] local anaesthetics [21][22][23][24] and NSAID. 25 The mechanism of this potentiation may include reduced development of tolerance to opioids 26 and reduced tachyphylaxis to local anaesthetics.…”

Effects of Intravenous Small Dose Ketamine and Midazolam on Postoperative Pain Following Knee Arthroscopy

“…There have been a number of studies concerning the effect of intrathecal ketamine on postoperative pain 4,7–10,25–32 . The results of these studies have been conflicting.…”

“…Ketamine also has been administered intraspinally, where its effect enhances the effect of epidural anesthesia. It has been used alone or in combination with other drugs, such as morphine and midazolam 3,4,7–10 . Fewer studies have shown that administration of intravenous ketamine improved postoperative analgesia after both spinal and epidural anesthesia 11,12 …”

Epidural ketamine for postoperative analgesia

“…Epidural ketamine may have an adjuvant effect when added to epidural morphine s or local anaesthetic agents. 9 Wong et al s administered 10 mg ketamine and 0.5 mg morphine epidurally to patients scheduled for major joint replacement. The kelanainc/morphine combination produced the same degree of analgesia (with movement) as did 2 mg epidural morphine alone.…”

“…Dans cette &ude, 10% des patients ont present6 des effets psychotomimttiques n&essitant traltement. Yanli et al 9, dans une &ude contr61&, ont ajout6 25 mg de k&anfine/t une solution de bupivacai'ne 0,5% adrc3nalin& ~ 1:200,000 et ont administr~ par vole 6pidurale 20 ml de la solution ~ des patients pour des chirurgies abdominales basses ou orthoptdiques. Le groupe k&amine a pr&ent6 un d~but d'anesth&ie 16gtrement mals significativement plus rapide et un bloc segmentaire 16g~rement plus haut.…”