C. Beattie

Double-masked randomized trial comparing alternate combinations of intraoperative anesthesia and postoperative analgesia in abdominal aortic surgery

Background Improvement in patient outcome and reduced use of medical resources may result from using epidural anesthesia and analgesia as compared with general anesthesia and intravenous opioids, although the relative importance of intraoperative versus postoperative technique has not been studied. This prospective, double-masked, randomized clinical trial was designed to compare alternate combinations of intraoperative anesthesia and postoperative analgesia with respect to postoperative outcomes in patients undergoing surgery of the abdominal aorta. Methods One hundred sixty-eight patients undergoing surgery of the abdominal aorta were randomly assigned to receive either thoracic epidural anesthesia combined with a light general anesthesia or general anesthesia alone intraoperatively and either intravenous or epidural patient-controlled analgesia postoperatively (four treatment groups). Patient-controlled analgesia was continued for at least 72 h. Protocols were used to standardize perioperative medical management and to preserve masking intraoperatively and postoperatively. A uniform surveillance strategy was used for the identification of prospectively defined postoperative complications. Outcome evaluation included postoperative hospital length of stay, direct medical costs, selected postoperative morbidities, and postoperative recovery milestones. Results Length of stay and direct medical costs for patients surviving to discharge were similar among the four treatment groups. Postoperative outcomes were similar among the four treatment groups with respect to death, myocardial infarction, myocardial ischemia, reoperation, pneumonia, and renal failure. Epidural patient-controlled analgesia was associated with a significantly shorter time to extubation (P = 0.002). Times to intensive care unit discharge, ward admission, first bowel sounds, first flatus, tolerating clear liquids, tolerating regular diet, and independent ambulation were similar among the four treatment groups. Postoperative pain scores were also similar among the four treatment groups. Conclusions In patients undergoing surgery of the abdominal aorta, thoracic epidural anesthesia combined with a light general anesthesia and followed by either intravenous or epidural patient-controlled analgesia, offers no major advantage or disadvantage when compared with general anesthesia alone followed by either intravenous or epidural patient-controlled analgesia.

Control of blood pressure and heart rate in patients randomized to epidural or general anesthesia for lower extremity vascular surgery

STUDY OBJECTIVE To examine the degree of success at maintaining patients randomized to epidural or general anesthesia for peripheral vascular surgery within predetermined blood pressure (BP) and heart rate (HR) limits. To investigate associations between such hemodynamic control and intraoperative myocardial ischemia and postoperative major cardiac morbidity. DESIGN Prospective randomized clinical trial. SETTING University-affiliated hospital. PATIENTS 100 patients undergoing elective lower extremity revascularization for atherosclerotic peripheral vascular disease. INTERVENTIONS Patients were randomized to receive either epidural anesthesia or general anesthesia. Blood pressure and HR limits were determined prior to randomization. Hemodynamic monitoring and management of anesthesia was standardized. Myocardial ischemia and major cardiac morbidity were diagnosed by a blinded cardiologist, based on continuous ambulatory ECG monitoring, cardiac enzymes, and 12 lead ECGs. Intraoperative BP and HR date were analyzed by investigators masked to the type of anesthesia given. MEASUREMENTS AND MAIN RESULTS A greater percentage of patients randomized to general anesthesia had intraoperative BPs more above their limit (95% vs 72%, p = 0.002) and/or more rapid changes in HR (75% vs 48%, p = 0.008) or BP (100% vs 93%, p = 0.04) than those randomized to epidural anesthesia. Intraoperative ischemia and major cardiac morbidity were similar in the two anesthesia groups. Patients experiencing intraoperative ischemia, regardless of anesthetic type, more frequently had BPs greater than 10% above their upper limit (90% vs 60% p = 0.04) and/or more rapid HR changes (90% vs 58%, p = 0.03) compared with patients without ischemia. These vital sign abnormalities, however, were not necessarily temporally related to the ischemic episodes. Patients experiencing subsequent major cardiac morbidity were not different from other patients with respect to excursions out of BP on HR limits. CONCLUSIONS Prevention of elevated intraoperative BP and/on rapid changes in BP or HR may be more successful with epidural than with general anesthesia. Such vital sign abnormalities may occur more frequently in patients who have had intraoperative ischemia or are at risk for having it later in the procedure.

A Proposed Method for the Measurement of Anesthetist Care Variability

Objective.Some critical events in anesthesiology occur as seemingly preventable misadventures, their exact origins indeterminable. In experienced anesthetists, anesthesia machine malfunctions, lack of vigilance and human error inevitably initiate some incidents [1]. Anesthesia training improves recognition and decision-making. Avoiding crisis initiation andamelioration of those that do occur is one role of the consultant anesthesiologist [2]. Safe patient care requires medical and procedural knowledge, technical expertise, and control of resources in a complex milieu [3]. Anesthesia simulators are clinical laboratories where anesthetists can sharpen both cognitive and manual skills [4, 5, 13]. Dynamic scenarios allow opportunities for anesthetists to explore and experience crises as they develop and apply their knowledge while attempting to manage these events [6]. Simulator-based scenarios are reproducible and large amounts of useful data can be collected and saved [7]. The authors hypothesize these data can be utilized to compare performance of anesthetists and to measure improvement of individual anesthetists over time. Methods.We have designed “StableAnesthesia,” a prototypic scenario to test anesthetists’capabilities under the stress of performance guidelines. Three subjects performed anesthesia using the simulator and this protocol. Data from the simulator were archived by the system and analyzed by the authors. Results.A simple mathematical analysis gave good separation of data from three subjects of different training level. Conclusions.It is suggested that the use of the techniques mentioned here may be of value in the development of a standardized testing protocol for anesthetists.