A prospective study to select and evaluate anesthesiology residents: phase I, the critical incident technique.

STUDY OBJECTIVE: To develop categories of behavior that define an applicant's aptitude for anesthesia, and to attempt to determine the relative importance of these behaviors to successful residency performance. DESIGN: Prospective open study. SETTING: Anesthesia residencies at three midwest university teaching hospitals. INTERVENTIONS: Using a structured interview format known as the critical incident technique, faculty anesthesiologists were asked to describe examples of effective and ineffective behaviors observed among anesthesia residents during the twelve months prior to the interview. MEASUREMENTS AND MAIN RESULTS: Interviews initially held with 34 anesthesiologists generated 172 incidents. These incidents formed the basis for a categorization analysis performed by two anesthesiologists. Six categories were developed: preparedness, interpersonal skills, response to teaching, data monitoring, technical skills, and emergency situations. Validation of these categories was confirmed with three subsequent interviews, in which 92 anesthesiologists generated 475 incidents. Most incidents were found to conform to the previously defined categories using a reallocation index with a range of 0.70 to 0.80. The category "technical skills" fell below the defined range. Over 60 percent of the incidents involved noncognitive personal attributes: preparedness, interpersonal skills, and response to teaching. CONCLUSION: Effective behavior in six categories identifies an applicant's aptitude for anesthesia. Selection of residents may be enhanced by routinely assessing noncognitive characteristics.

Assessment of an interactive learning system with "sensorized" manikin head for airway management instruction.

An interactive, self-study learning system for airway management instruction that utilizes a "sensorized" manikin head (Actronics Inc., Pittsburgh, PA) was compared to didactic instruction from anesthesiologists during third-year medical student anesthesia rotations. Before students were allowed to participate in airway management on anesthetized patients, they were randomly separated into two groups. One group received instruction from the learning system, and the other group was given a lecture with guided practice on a standard tracheal intubating manikin. Differences between groups were then assessed using 22 separate variables as all students performed actual airway management on patients undergoing general anesthesia. Anesthesia faculty, residents, and nurse anesthetists, blinded to group, served as assessors. There were 48 and 49 students in the didactic instruction and learning system groups, respectively. Beginning experience level of students with respect to airway management was similar between groups before the anesthesia rotations. There were 185 and 188 evaluation forms completed to assess the didactic instruction and learning system groups, respectively. Demographic data regarding patients were recorded. Patients in the learning system group on whom students performed airway management were older, had a larger average body mass index, and their airways more frequently received higher Mallampati classifications (glottic structures more difficult to visualize). No difference in the quality of airway management efforts or in students' appraisal of their own performances was seen between groups. Neither group demonstrated more rapid development of psychomotor skills. Students were equally satisfied with both methods of instruction.(ABSTRACT TRUNCATED AT 250 WORDS)

Continuous enteral feeding and short fasting periods enhance perioperative nutrition in patients with burns.

Both retrospective and prospective analyses of the effects of various fasting regimens were carried out on the achievement of calculated caloric needs of patients with severe burns. The records of patients who received enteral feedings while undergoing burn debridements were divided into three groups and retrospectively analyzed to determine the effect that duration of fasting had an achievement of caloric needs and on the risks of aspiration. Patients in two other groups were prospectively studied to determine the safety and efficacy of stopping continuous enteral feedings 1 and 4 hours before surgery, respectively. Techniques of airway management and anesthetic induction were left to the discretion of the attending anesthesiologist. In the retrospective analysis, patients in group I, who fasted for 2 hours achieved 28% of their calculated 24-hour caloric goals compared with 11% in those who fasted for 2 to 8 hours (group II) and 6% in those who fasted for more than 8 hours (group III) before surgery (p less than 0.001). In the prospective portion of the study, patients who fasted for 1 hour before anesthesia was induced achieved 30% of their caloric needs, whereas those who fasted for 4 hours achieved 15% of their target nutritional needs (p = 0.0001). No patient had evidence of pulmonary aspiration. We conclude that controlled enteral feedings and shortened preoperative fasting periods can safely enhance nutritional support in patients with burns.

Changes in plasma potassium and neuromuscular blockade following suxamethonium in patients pre-treated with terbutaline.

Plasma potassium, heart rate, systolic and diastolic blood pressure were measured in adult surgical patients pre-treated with either terbutaline 1.25 mg (n = 10) or normal saline (n = 10) prior to and during general anaesthesia which included suxamethonium 1 mg kg-1. Neuromuscular blockade was then measured using a train-of-four technique. Plasma potassium was significantly lower before and during general anaesthesia in those patients who had received terbutaline but the rise following suxamethonium (measured at 1, 3, 5, 7, 10, 12, 15, 30 and 180 min after suxamethonium) was similar in both groups. Heart rate increased significantly in the treatment group both over time and compared to the control group. Onset time to maximum neuromuscular blockade and duration of blockade was shorter in the terbutaline-treated group.

Anesthesia for craniotomy: a double-blind comparison of alfentanil, fentanyl, and sufentanil.

Using a prospective, randomized, and double-blind study design, alfentanil (n = 15), fentanyl (n = 14), or sufentanil (n = 16), in combination with N2O, were administered to patients undergoing craniotomy for supratentorial tumor resection. Physicians were given two syringes, one of which was labeled as "load" for the initial loading dose and the other as "maintenance" for continuous infusion. The concentration of drug in each syringe was adjusted to permit administration on a milliliter per kilogram basis. The target loading doses for alfentanil, fentanyl, and sufentanil were 75, 10, and 1 microgram/kg, respectively, and initial infusion rates were 33.5, 2.0, and 0.3 microgram.kg-1.h-1, respectively. Additional supplementary boluses and changes in maintenance infusion rate were made according to predetermined guidelines. Isoflurane, in increasing 0.2% inspired increments, was used only when the maximum allowed opioid dose had been given (i.e., supplementary bolus doses equal to 75% of the calculated loading dose or supplementary bolus doses equal to 50% of the calculated loading dose combined with a 50% increase in the maintenance infusion rate). Opioid infusions were stopped at the time of bone flap replacement. Antihypertensive medications and naloxone were subsequently given at the discretion of the anesthesiologist. Group demographics were not different. Total volumes of drug were similar among groups indicating equipotent preparations. Administration of isoflurane, antihypertensive medications, and naloxone were not different among groups. Although decreases in blood pressure seen with induction were similar among groups, alfentanil-treated patients received ephedrine more frequently before intubation. Thirty minutes after entry into the postanesthesia recovery area, respiratory rate and pH were lowest in sufentanil-treated patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Neuromuscular and cardiovascular effects of mivacurium chloride (BW B109OU) during nitrous oxide-narcotic, nitrous oxide-halothane and nitrous oxide-isoflurane anesthesia in surgical patients.

One hundred seventeen adult surgical patients were studied to compare neuromuscular and cardiovascular effects of mivacurium chloride during nitrous oxide-narcotic (BAL, n = 45) nitrous oxide-halothane (HAL, n = 27) and nitrous oxide-isoflurane (ISF, n = 45) anesthesia. Anesthesia was maintained with nitrous oxide (60%-70%) and oxygen (30%-40%) with end-tidal concentrations of halothane or isoflurane to yield a total MAC of approximately 1.25, or with supplemental fentanyl and thiopental as clinically indicated. Twitch response of the adductor pollicis muscle was elicited by supramaximal square wave pulses of 0.2 msec duration at a frequency of 0.15 Hz (Grass S44 stimulator) to the ulnar nerve and quantitated by a Grass FT10 transducer. Nine patients in each of the HAL and ISF groups received one of four doses of mivacurium (0.03, 0.05, 0.10 or 0.15 mg/kg). Ninety patients in the balanced anesthesia group received one of seven doses of mivacurium (0.03, 0.04, 0.05, 0.08, 0.15, 0.20, 0.25 mg/kg). The ED50, ED75 and ED95 of mivacurium in each group were estimated from linear regression plots of log dose versus probit of maximum percentage depression of twitch height. The ED50, ED75 and ED95 for halothane and isoflurane are 0.040, 0.053 and 0.081 and 0.037, 0.043 and 0.053, respectively. The ED50, ED75, and ED95 for the balanced group are 0.039, 0.050, and 0.073 mg/kg respectively. There was no significant difference between the slopes of the HAL and BAL inhalation anesthetic dose-response curves. The slope of the ISF group was significantly than the slope of the BAL group. Intercepts of the HAL and BAL curves were not different. The isoflurane curve's intercept was significantly less than the other groups' intercepts, lying above the halothane curve, but below the BAL curve. For the 0.05 mg/kg dose, maximum block was greater in the ISF group (89.1 +/- 2.7%, n = 9) than in the HAL (70.3 +/- 7.6%, n = 9) or BAL (67.7 +/- 6.4%, n = 9) groups. At higher doses of mivacurium, isoflurane produces a greater potentiation of neuromuscular block than halothane or balanced anesthesia. There were no significant cardiovascular changes seen in any group following mivacurium doses up to 0.15 mg/kg (approximately 2xED95).

Effects of alfentanil and lidocaine on the hemodynamic responses to laryngoscopy and tracheal intubation.

This study was undertaken to determine whether lidocaine and/or alfentanil can effectively abolish or attenuate the increase in mean arterial pressure (MAP), heart rate (HR), and rate pressure product (RPP) associated with rapid sequence induction of anesthesia. Sixty patients were randomly divided into four groups. Group 1 received saline 10 ml, group 2 received lidocaine 2 mg/kg, group 3 received alfentanil 15 micrograms/kg, and group 4 received alfentanil 30 micrograms/kg. All patients were induced with sodium thiopental 4 mg/kg and succinylcholine 1.5 mg/kg to facilitate tracheal intubation. The study drug was given after sodium thiopental was administered, and the investigator was blinded to it. Blood pressure (BP) and HR were recorded at the following times: before induction; after induction but before laryngoscopy and intubation; and 1, 3, and 5 minutes after intubation. Alfentanil 15 and 30 micrograms/kg given in rapid sequence fashion with thiopental and succinylcholine effectively blunted the hemodynamic responses to laryngoscopy and tracheal intubation. Lidocaine 2 mg/kg and saline were found to be ineffective in blunting these same responses.

Neuromuscular and cardiovascular effects of mivacurium chloride (BW B1090U) during nitrous oxide-fentanyl-thiopentone and nitrous oxide-halothane anaesthesia.

Seventy-two adult surgical patients were studied to compare neuromuscular and cardiovascular effects of mivacurium chloride during nitrous oxide-fentanyl-thiopentone (BAL group) or nitrous oxide-halothane (HAL group) anaesthesia. Eighteen patients in the BAL group received an initial bolus of mivacurium, either the ED25 (n = 9) or the ED50 (n = 9) (0.03 and 0.05 mg kg-1). These doses were based on the assumption that the slope of the dose-response curve during nitrous oxide-opioid anaesthesia would be approximately the same as the slope of the neuromuscular response from the first human studies with mivacurium. Twenty-seven additional patients were allocated to subgroups of nine patients to receive mivacurium 0.04, 0.08 or 0.15 mg kg-1. Twenty-seven patients in the HAL group were allocated also to subgroups of nine patients to receive mivacurium 0.03, 0.04 or 0.15 mg kg-1. During stable anaesthesia, mean endtidal halothane concentrations were maintained at 0.49 +/- 0.01%. The estimated ED50, ED75 and ED95 for BAL and HAL groups were 0.039, 0.05 and 0.073 mg kg-1 and 0.040, 0.053 and 0.081 mg kg-1, respectively. Halothane did not potentiate maximum block or time to maximum block. Halothane did affect spontaneous recovery. With the 0.15-mg kg-1 dose, time to 95% recovery was prolonged significantly in the HAL group (30.0 (SEM 1.4) min) compared with the BAL group (24.1 (1.5) min). Recovery index from 25% to 75% recovery was also prolonged significantly in the HAL group (7.0 (0.4) min) compared with the BAL group (5.4 (0.4) min). There were no significant haemodynamic changes in groups given mivacurium doses up to and including 2 x ED95 by bolus i.v. administration.

Operating room management: the role of the anesthesiologist.

Operating room management structures and interrelationships both within the operating suite and with other departments in the hospital can be extremely complex. Several different professional and support groups are represented that often have infrastructures of their own that may compete or conflict with the operating room's management hierarchy. Often, there really is little actual management of the operating suite as an entity. Because the units must interact effectively to provide a high level of patient care, it is important that areas of conflict be resolved. Many problems can be averted by implementation of specific policies and procedures, after appropriate action by the medical staff outlining operating room goals and objectives, and the establishment of realistic lines of authority and communication. More important than the actual structure of the management components in developing an efficient and successful operating room is the ability of key management personnel to understand the dynamics of people and situations as they evolve. Management must also continually monitor and objectively evaluate the system so that areas of deficiency of conflict may be identified and policies or procedures adapted to adequately meet the changing needs of staff and patients. Anesthesiologists are in unique positions to deal with many of these problems and should play an active role in their resolution. As physicians and consultants, we have an understanding of the burden faced by surgeons relative to patient care. Because the majority of our working time is spent in the operating room, we have an opportunity to develop an effective working relationship with nursing staff.(ABSTRACT TRUNCATED AT 250 WORDS)

Serum potassium concentrations following succinylcholine in patients undergoing beta-adrenoceptor blocking therapy.

Efflux of serum potassium following succinylcholine was compared in surgical patients undergoing low-dose, long-term beta 1-adrenoceptor or beta 1,2-adrenoceptor blocking therapy and in those receiving neither of these therapies. There were no significant differences in serum potassium concentration prior to, and over a study period of, 2 hours following succinylcholine administration among the three groups of patients.

Ventilatory frequency influences accuracy of end-tidal CO2 measurements. Analysis of seven capnometers.

An accurate high-frequency response is mandatory when end-tidal CO2 (PETCO2) is monitored during pediatric general anesthesia. The purpose of this study was to assess the accuracy of six infrared-based capnometers and one multiplexed mass spectrometer available at our institution at increasing frequency. Capnometers studied were the Datascope Accucap, Hewlett-Packard 47210A capnometer, Narkomed 3 Capnomed, Novametrix Capnogard model 1250, Perkin-Elmer Advantage, Puritan-Bennett Datex CO2 monitor, and Traverse Medical Monitor model 2200 capnometer. Changes in CO2 concentration were generated by a solenoid valve switching between 100% O2 and 7% CO2 in O2. Frequencies, 8-101 cycles/min were chosen to stimulate a range that might be generated by children during general endotracheal anesthesia. At every rate the displayed PETCO2 was recorded. Differences in displayed PETCO2 from known CO2 ranged from -16.4 to +6.6. At or below frequencies of 31 cycles/min, four capnometers overreported and three underreported PETCO2. At frequencies above 31 cycles/min, six capnometers underreported and one overreported PETCO2. Errors may be clinically significant if they influence ventilator settings for patients.