Evaluation of efficacy of low dose ketamine in relieving intraoperative post child birth pain in lower segment caesarean section: a prospective, randomised, double-blind case control study

­­­­A reasonable proportion of parturients undergo Caesarean delivery, due to varied indications. A good fraction of the caesarean deliveries takes place under the subarachnoid/spinal anaesthesia. This anaesthesia is considered the gold standard because it allows the woman to see the newborn intraoperatively, can provide good postoperative analgesia, and obviates need for airway manipulation. A potentially devastating complication of spinal anaesthesia for Caesarean Delivery is intraoperative pain also described as Pain during caesarean delivery (PDCD). The incidence of intra operative pain is around 11.9% in the population undergoing the surgery.Intraoperative pain can cause long term psychological and physical consequences. Significant pain during caesarean may affect the patient experience and has been associated as an independent risk factor for postpartum post-traumatic stress disorder. Pain associated with caesarean section may occur before the delivery of baby, after delivery of baby or may be present throughout the procedure. Preoperative anxiety may contribute to a pain sensation in initial duration of the procedure. Pain following child birth can be attributed to the use of oxytocin, uterus exteriorization, peritoneal or mesenteric pull, amniotic fluid embolism. Parturient may experience different types of pain and discomfort following birth, including cramping pain (often called after-birth pain) associated with uterine involution, where the uterus contracts to reduce blood loss and return the uterus to its non pregnant size.

Ketamine is an N-methyl-d-aspartate (NMDA) receptor inhibitor that causes analgesia by desensitization of stimulated N-methyl-d-aspartate receptor, thereby blocking pain signal in central nervous system. . Ketamine has a minimal effect on the central respiratory drive if given slowly, although rapid iv injection can cause transient apnoea. Ketamine may provoke imaginative, dissociative states and psychotic symptoms resembling schizophrenia due to its NMDA-antagonistic action, as well as severely impairing semantic and episodic memory. Subanaesthetic doses of ketamine prevent central sensitization, development of acute opioid tolerance, and hyperalgesia. Low-dose ketamine also decline the activity of brain structures that respond to noxious stimuli. It has effects on opioid receptors and stimulates monoaminergic descending inhibitory pathways at supraspinal sites causing in antinociception, all of which mediate analgesic effects. Ketamine is used increasingly in sub-anaesthetic doses as an adjuvant to local anaesthetics and opioids in multimodal pain therapy for acute pain management.

The study aims at evaluation of the effect of intraoperative Ketamine administration in relieving the pain during caesarean section, as well as post operatively.