Effects of intrathecal ketamine added to bupivacaine for spinal anaesthesia

Abstract

We prospectively studied 30 healthy female patients undergoing intracavitory brachytherapy applicator insertion for carcinoma of the cervix under spinal anaesthesia. Patients were randomly allocated to receive either intrathecal bupivacaine 10 mg alone or bupivacaine 7.5 mg combined with preservative-free ketamine 25 mg. Spinal block onset, maximum sensory level, duration of blockade, haemodynamic variables, postoperative analgesic requirements and adverse events were recorded. Onset of sensory and motor block and duration of spinal analgesia were comparable between groups. Duration of motor blockade was shorter (p 0.0416) and requirement for intravenous fluids in the peri-operative period was less (p 0.0159) in the ketamine group. Significantly more patients in the ketamine group had adverse events, such as sedation, dizziness, nystagmus,`strange feelings' and postoperative nausea and vomiting. Although the addition of ketamine to spinal bupivacaine had local anaesthetic sparing effects, it did not provide extended postoperative analgesia or decrease the postoperative analgesic requirements. Moreover, the central adverse effects of ketamine limit its spinal application. Reducing the dose of bupivacaine used in spinal anaesthesia helps to achieve rapid anaesthetic recovery but may result in anaesthetic failure [1]. Intrathecal adjuncts, such as opioids [2], vasoconstrictors [3], alpha-2 agonists [4], and neostigmine [5] are often added to enhance spinal anaesthesia. Even though these adjuncts are effective in improving the efficacy of low-dose spinal anaesthesia, their use is limited because of side-effects [2±5].Ketamine is an anaesthetic agent with potent analgesic properties. Its mode of action includes noncompetitive antagonism at N-methyl d-aspartate (NMDA) receptors and a local anaesthetic effect [6]. Intrathecal ketamine has been evaluated as a sole anaesthetic agent [7,8], but psychomimetic disturbances and inadequate analgesia precluded its use for this purpose. In this study, we evaluated the effects of intrathecal ketamine added to a small dose of spinal bupivacaine in patients with carcinoma of the cervix undergoing intracavitory brachytherapy applicator insertion. MethodsAfter obtaining approval from our Institutional Ethics Committee and informed patient consent, we enrolled 60 female, ASA physical status I or II patients with carcinoma of the cervix undergoing intracavitory brachytherapy implants (ovoids and tandems) insertion under spinal anaesthesia. Patients were randomly allocated to receive q 2000 Blackwell Science Ltd 899 either intrathecal hyperbaric bupivacaine 10 mg alone (0.5% Sensorcaine in 8.25% dextrose; Astra-IDL, India) or bupivacaine 7.5 mg with preservative-free ketamine 25 mg (Aneket 5%, Neon Laboratories, India). The patients and the doctor who observed the patients in the recovery room were blinded to the treatment.The Verbal Numerical Scores (VNS) system for assessment of pain was explained during the pre-operative visit. Patients were fasted for 6 h pre-operatively and premed...

Evaluation of Addition of Low Dose Midazolam to a Mixture of Low Dose Ketamine and Hyperbaric Bupivacaine Given in Subarachnoid Block in Patients Undergoing Lower Limb Orthopaedic Surgery

“…All the patients in both group attained Bromage grade 3. Our result is comparable with those of TM Krishna et al (2008), Kathirvel et al (2000) and Bharti N et al (2003). Duration of motor block in our study was in consonance with that of TM Krishna et al (2008) who also showed prolongation of motor block in midazolam-ketamine-bupivacaine group as compared to ketamine-bupivacaine group.…”

“…N Bharti et al (2003) showed that changes in blood pressure and pulse rate were comparable between midazolambupivacaine and bupivacaine alone group. Kathirvel et al (2000) also showed that patients in ketamine-bupivacaine group had significantly higher systolic and diastolic blood pressure after induction of spinal anaesthesia and also volume of intravenous fluid required to maintain blood pressure was lower in ketamine-bupivacaine group. Kaliyani et al (2001) in their study also showed that intrathecally administered ketamine caused dose dependent mild increase in pulse rate and systolic blood pressure.…”

“…Bharti N et al (2003) in their study also showed prolongation of motor block with addition of midazolam to bupivacaine. Kathirvel et al (2000) in their study showed that duration of motor blockade was shorter in ketamine-bupivacaine group as compared to bupivacaine alone. Spinal anaesthesia produce sensory, motor and sympathetic blockade.…”

“…The duration of sensory block in our study was in resemblance to that of TM Krishna et al (2008) who also noticed significant prolongation of sensory block in midazolam-ketaminebupivacaine group as compared to ketaminebupivacaine group. Kathirvel et al (2000) in their study showed that no significant difference occur in duration of sensory block with addition of ketamine to bupivacaine while Bharti N et al (2003) and Mia JY et al (2007) in their study showed that significant prolongation in duration of sensory block occur with addition of midazolam to bupivacaine. Reason for short duration of sensory block in Group K may be due to shorter duration action of ketamine as compared to bupivacaine.…”

COMPARISON OF INTRATHECAL BUPIVACAINE (17.5mg) WITH PRESERVATIVE FREE MIDAZOLAM (1mg) VERSUS INTRATHECAL BUPIVACAINE (17.5mg) FOR POSTOPERATIVE PAIN RELIEF IN LOWER LIMB SURGERIES.

“…However, they provide a very limited postoperative duration of action. In order to overcome this problem and to maximise the duration of analgesia, many adjuvants, for example opioids 4 , neostigmine 4 , ketamine 5 and clonidine 6 ,have been tried increasingly in the last two decades to relieve postoperative pain. However, side-effects in the postoperative period such as nausea, vomiting, pruritus, urinary retention and respiratory depression, render most adjuvants as less than ideal.…”