Use of an Anesthesia Information Management System (AIMS) to Evaluate the Physiologic Effects of Hypnotic Agents Used to Induce Anesthesia

Objective: The aim of this study was to utilize an anesthesia information management system (AIMS) in investigating the effects of hypnotic agents used to induce anesthesia on blood pressure, heart rate and arterial oxygen saturation. The characteristics of these agents, known from previous studies, were compared to the effects documented in this study during routine clinical use.

Methods: During the years 1997 and 1998, all relevant data from anesthetic procedures were recorded online using the automated anesthesia information system NarkoData. The data from 8,078 general anesthesia procedures using endotracheal intubation were exported via "structured query language" (SQL) from the AIMS database into a statistics program after excluding children (age < 14), patients who received atropine during induction and procedures with use of extracorporeal circulation. The effects of drug administration on systolic, diastolic and mean arterial blood pressure (SBP, DBP, MBP), heart rate (HR) and arterial oxygen saturation (SpO2) were analyzed prior to induction and at 5, 10 and 15 minutes following bolus administration of the hypnotic agent. The data were classified into three groups based on the induction agent used: thiopental, etomidate or propofol and further separated into two groups based on ASA status (ASA < or = II and ASA > II). The mean and standard deviations were calculated for each parameter at each point in time. Statistical comparisons were performed to determine whether the results for each time point differed from the previous time point.

Results: There was a significant decrease in blood pressure (MAP, SBP, DBP) after bolus administration of all three hypnotics in all of the 8,078 procedures analyzed. The decrease was greater in patients of ASA class > II than in those of ASA class < or = II. Propofol caused the greatest drop in blood pressure whereas etomidate caused the least. During the observation period the HR also fell in each group, except for thiopental where an initial rise of the HR could be observed. An initial rise of SpO2 was recorded in each group with no differences observed between the individual hypnotics.

Conclusions: The effects of the induction hypnotic agents thiopental, etomidate and propofol on blood pressure and heart rate as documented by an AIMS corresponded to those found in clinical studies. An AIMS with the corresponding documentation, software and database structure is suitable for collecting and evaluating data for dinical investigations.