Efficacy of Preemptive Single Dose Intravenous Ketamine Hydrochloride on Postoperative Analgesia after Lower Abdominal Surgery

Abstract

Many mi11ions of patients orldwide undergo surgery eaCh year and

most aspects of modem surgical ircatmenL Alihough eiTective pain control is essential for op mai care of surgical patientsand despite advances in knowledge of pathophysiology, pha.'1llacology of analgesics, a.1d the development of more eiTectiYe techniques for perioperative analgesia, many patients continue to experience distre.ssing pain.

proYokes !\Yo kinds of modif1cation in responsi-reness of the ner>:ous systen1; peripheral sensitization \Yith reduction n thre hc1d of noc ceptor aft .ren1 per phera1 termina1s and c-entral

neurons. contribute parn

in the response t(.i noxious slirnul! and. a decrease in lhe pain threshold.. both

at sie of 1rj ury and .in the surrounding w"'11nj ured iissues.

Expen.mentaJ da.la Indicate that I'-i-methyl-D-aspartic acid (NMDA)

.receptors are irnportru1t in sustaining and n1agnifying excitability of neurons in the spinal cord. NMDA receptor antagonists have been shmYn to prevent the in(!uction of central sensitization and abolish the hypersensitiyity once it is established.