摘要
The purpose of this study is to assess the effects of propacetamol on attenuating hemodynamic responses subsequent laryngoscopy and tracheal intubation compared to lidocaine. In this randomized clinical trial, 62 patients with the American Anesthesiologists Society (ASA) class I/II who required laryngoscopy and tracheal intubation for elective surgery were assigned to receive propacetamol 2ˋg/I.V./infusion (group P) or lidocaine 1.5ˋmg/kg (group L) prior to laryngoscopy. Systolic and diastolic blood pressures (SBP, DBP), mean arterial pressure (MAP), and heart rate (HR) were recorded at baseline, before laryngoscopy and within nine minutes after intubation. In both groups P and L, MAP increased after laryngoscopy and the changes were statistically significant ( ). There were significant changes of HR in both groups after intubation ( ), but the trend of changes was different between two groups ( ). In group L, HR increased after intubation and its change was statistically significant within 9 minutes after intubation ( ), while in group P, HR remained stable after intubation ( ). Propacetamol 2ˋgr one hour prior intubation attenuates heart rate responses after laryngoscopy but is not effective to prevent acute alterations in blood pressure after intubation. 1. Introduction Propacetamol [4-(acetamido)phenyl N,N-diethylglycinate] is a prodrug, which is quickly hydrolyzed by plasma esterase to vigorous paracetamol; 1ˋgr propacetamol metabolized to 500ˋmg paracetamol [1]. It has an onset of about half an hour to an hour, has a half-life of one to four hours, and has duration effect of six to eight hours. Its optimal effects appear about one hour after injection and its maximum recommended dose in adults is 4 grams per day. This drug inhibits prostaglandins synthesis in the central nervous system and also blocks pain impulses peripherally and has antipyretic effects through hypothalamus [2]. This drug is safe, cost effective and its beneficial effects for pain management and reducing opioids amounts have been confirmed in patients who underwent dental, orthopaedic and gynaecologic surgeries [3每8]. Laryngoscopy and tracheal intubation are among the most painful processes carried out on the human body which are associated with acute hemodynamic responses, lasting for at least ten minutes [3每9]. Sympathoadrenal stimulation and subsequent catecholamine release may partially contribute to this hemodynamic instability, which is typically signified by an increase in heart rate (HR) and blood pressure (BP) [10]; however, the main mechanism is not clearly defined.