Intravenous Low Dose Ketamine Infusion for Labour Analgesia: A Prospective Interventional Clinical Trial

Anita Shirley Joselyn, - (2007) Intravenous Low Dose Ketamine Infusion for Labour Analgesia: A Prospective Interventional Clinical Trial. Masters thesis, Christian Medical College, Vellore.

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Abstract

INTRODUCTION: Pain during labour and delivery is intense, although there is considerable variability in its perception. The commonly employed methods of pain relief in labour include systemic analgesics, inhalational anaesthetics, and regional techniques. Pethidine is the most commonly used systemic analgesic which provides moderate analgesia, but it causes sedation, nausea and vomiting in the mother and respiratory depression in the neonate. Inhalation of a mixture of nitrous oxide and oxygen (Entonox) provides analgesia, but it requires good maternal co-operation to be effective. An epidural local anaesthetic with opioids provide good relief of pain during labour, but is associated with prolongation of the second stage of labour and an increased incidence of instrumental vaginal delivery. It is also relatively expensive and needs an expert to initiate the block. Ketamine is a short acting anesthetic with excellent analgesic property, and has been widely used for short surgical procedures like wound suturing and dressing in the out patient department. It has been safely used in obstetrics as an induction agent for caesarean section, manual removal of placenta, and for forceps delivery. It has been shown that in low doses, intravenous ketamine provides good intraoperative and postoperative analgesia. This prospective interventional study was an effort to evaluate the efficacy of low dose ketamine as a labour analgesic, thereby providing a safe and inexpensive alternative, especially for the developing countries with limited resources and economical constraints. AIM OD THE STUDY: The aims of this study are: 1. To evaluate the efficacy of low dose intravenous ketamine in providing analgesia during labour. 2. To assess the safety of low dose intravenous ketamine on the parturient and the fetus, and its effect on the progress of labour. 3. To standardise a “low dose ketamine” regimen for labour analgesia. PATIENTS AND METHODS: This interventional study was a prospective evaluation conducted in the labour room of a tertiary referral hospital after obtaining approval from the Research and Ethics committee of the institution. METHODOLOGY: Parturients with no antenatal risk factors and expected to have normal vaginal delivery were eligible to be included in the study. Women with known cardiac disease, gestational hypertension, epilepsy or known psychiatric disorder were excluded, as were parturients with multifetal pregnancy, suspected cephalopelvic disproportion and those who have had previous caesarean section. Study Intervention: All the parturients eligible for the study were explained about the procedure and a written consent obtained from the volunteers. A 20G intravenous cannula was inserted into the forearm which was used only for the infusion of ketamine. Racemic ketamine (Aneket®, Neon Laboratories) was loaded in a 50ml syringe in a concentration of 2mg.ml-1and connected to this intravenous cannula. A bolus dose of 0.1mg.kg-1 of ketamine was administered. This was followed by an infusion of ketamine at the rate of 0.2mg.kg-1.hr-1. The rate of the infusion was adjusted according to the pain perceived by the parturient during the uterine contraction and was altered as and when required. The infusion was stopped after the baby was delivered. STATISTICS: Since, continuous infusion of low dose ketamine has not been used during labour before, this pilot study was undertaken to assess its efficacy as a labour analgesic and to standardise a regimen. It was decided to do the initial evaluation on 30 parturients, and then ratify the dose regimen in a larger population, if ketamine was found to be effective. The results of the pilot study on 30 patients are presented. The statistical analysis was done using the Statistics Package for Social Sciences (SPSS® version 11). CONCLUSION: Although, systemic opioids, inhalational analgesia and regional techniques are widely used, effective control of labour pain with a technique which has minimal side effects on the parturient, the fetus and the progress of labour is yet to be found. Ketamine, a NMDA receptor antagonist, is shown to be an excellent analgesic. Although it is associated with unpleasant side effects, these can be minimised when ketamine is administered slowly in very low doses (0.1-0.2mg.kg-1.hr-1) while retaining its analgesic property. In this study, ketamine was administered as a bolus of 0.1mg.kg-1, followed by an infusion of 0.2mg.kg-1.hr-1 to parturients in active labour and was found to provide effective analgesia with minimal side effects. This technique was found to be acceptable both to the parturient and the obstetrician. However, minor modification to this technique, namely, a loading dose of 0.4mg.kg-1.hr-1 given over a period of 30minutes followed by an infusion of 0.15-0.2mg.kg-1.hr-1, would ensure rapid onset of analgesia while minimizing the side effects due to the bolus administration of the loading dose. Since, the efficacy and safety of low dose intravenous ketamine as a labour analgesic has been established, a regimen, with slight modification, would be ratified on a larger population, before being recommended as a standard technique of labour analgesia.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Intravenous Low Dose Ketamine Infusion ; Labour Analgesia ; Prospective Interventional Clinical Trial.
Subjects: MEDICAL > Anaesthesiology
Depositing User: Subramani R
Date Deposited: 30 Apr 2018 02:51
Last Modified: 30 Apr 2018 02:51
URI: http://repository-tnmgrmu.ac.in/id/eprint/7307

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