Narrative Review of Prolonged Times to Tracheal Extubation After General Anesthesia With Intubation and Extubation in the Operating Room.

This narrative review summarizes research about prolonged times to tracheal extubation after general anesthesia with both intubation and extubation occurring in the operating room or other anesthetizing location where the anesthetic was performed. The literature search was current through May 2023 and included prolonged extubations defined either as >15 minutes or at least 15 minutes. The studies showed that prolonged times to extubation can be measured accurately, are associated with reintubations and respiratory treatments, are rated poorly by anesthesiologists, are treated with flumazenil and naloxone, are associated with impaired operating room workflow, are associated with longer operating room times, are associated with tardiness of starts of to-follow cases and surgeons, and are associated with longer duration workdays. When observing prolonged extubations among all patients receiving general anesthesia, covariates accounting for most prolonged extubations are characteristics of the surgery, positioning, and anesthesia provider's familiarity with the surgeon. Anesthetic drugs and delivery systems routinely achieve substantial differences in the incidences of prolonged extubations. Occasional claims made that anesthesia drugs have unimportant differences in recovery times, based on medians and means of extubation times, are misleading, because benefits of different anesthetics are achieved principally by reducing the variability in extubation times, specifically by decreasing the incidence of extubation times sufficiently long to have economic impact (ie, the prolonged extubations). Collectively, the results show that when investigators in anesthesia pharmacology quantify the rate of patient recovery from general anesthesia, the incidence of prolonged times to tracheal extubation should be included as a study end point.

Relationship Between Glottic View and Intubation Force During Macintosh and Airtraq Laryngoscopy and Intubation.

BACKGROUND: Because intubation-mediated cervical spine and spinal cord injury are likely determined by intubation force magnitude, understanding the determinants of intubation force magnitude is clinically relevant. With direct (Macintosh) laryngoscopy, when glottic view is less favorable, anesthesiologists apply greater force. We hypothesized that, when compared with direct (Macintosh) laryngoscopy, intubation force with an optical indirect laryngoscope (Airtraq) would be less dependent on glottic visualization. METHODS: Using data obtained in a prior clinical study, we tested whether the slope of the intubation force versus glottic view relationship differed between intubations performed in 14 patients who were intubated twice, once with a Macintosh and once with an Airtraq videolaryngoscope. Slopes were compared using least-squares linear regression and robust regression. RESULTS: The slope of the intubation force (N) versus glottic view (%) relationship with the Macintosh (-0.679 [standard error {SE}, 0.147]) was significantly more negative than that of the Airtraq (-0.076 [SE, 0.246]). The least-squares regression difference in slopes was -0.603 (SE, 0.287); P = .046. The robust regression difference in slopes was -0.747 (SE, 0.187); P = .0005. Thus, when compared with the Macintosh, intubation force magnitude with Airtraq laryngoscopy was less dependent on glottic visualization. CONCLUSIONS: Previously, we reported that intubation force with the Airtraq was less in magnitude compared with the Macintosh. Our current study adds that intubation force also is less dependent on glottic view with Airtraq compared with the Macintosh.

Intubation Biomechanics: Clinical Implications of Computational Modeling of Intervertebral Motion and Spinal Cord Strain during Tracheal Intubation in an Intact Cervical Spine.

BACKGROUND: In a closed claims study, most patients experiencing cervical spinal cord injury had stable cervical spines. This raises two questions. First, in the presence of an intact (stable) cervical spine, are there tracheal intubation conditions in which cervical intervertebral motions exceed physiologically normal maximum values? Second, with an intact spine, are there tracheal intubation conditions in which potentially injurious cervical cord strains can occur? METHODS: This study utilized a computational model of the cervical spine and cord to predict intervertebral motions (rotation, translation) and cord strains (stretch, compression). Routine (Macintosh) intubation force conditions were defined by a specific application location (mid-C3 vertebral body), magnitude (48.8 N), and direction (70 degrees). A total of 48 intubation conditions were modeled: all combinations of 4 force locations (cephalad and caudad of routine), 4 magnitudes (50 to 200% of routine), and 3 directions (50, 70, and 90 degrees). Modeled maximum intervertebral motions were compared to motions reported in previous clinical studies of the range of voluntary cervical motion. Modeled peak cord strains were compared to potential strain injury thresholds. RESULTS: Modeled maximum intervertebral motions occurred with maximum force magnitude (97.6 N) and did not differ from physiologically normal maximum motion values. Peak tensile cord strains (stretch) did not exceed the potential injury threshold (0.14) in any of the 48 force conditions. Peak compressive strains exceeded the potential injury threshold (-0.20) in 3 of 48 conditions, all with maximum force magnitude applied in a nonroutine location. CONCLUSIONS: With an intact cervical spine, even with application of twice the routine value of force magnitude, intervertebral motions during intubation did not exceed physiologically normal maximum values. However, under nonroutine high-force conditions, compressive strains exceeded potentially injurious values. In patients whose cords have less than normal tolerance to acute strain, compressive strains occurring with routine intubation forces may reach potentially injurious values.

Reliability and Validity of Performance Evaluations of Pain Medicine Clinical Faculty by Residents and Fellows Using a Supervision Scale.

BACKGROUND: Annual and/or semiannual evaluations of pain medicine clinical faculty are mandatory for multiple organizations in the United States. We evaluated the validity and psychometric reliability of a modified version of de Oliveira Filho et al clinical supervision scale for this purpose. METHODS: Six years of weekly evaluations of pain medicine clinical faculty by resident physicians and pain medicine fellows were studied. A 1-4 rating (4 = "Always") was assigned to each of 9 items (eg, "The faculty discussed with me the management of patients before starting a procedure or new therapy and accepted my suggestions, when appropriate"). RESULTS: Cronbach α of the 9 items equaled .975 (95% confidence interval [CI], 0.974-0.976). A G coefficient of 0.90 would be expected with 18 raters; the N = 12 six-month periods had mean 18.8 ± 5.9 (standard deviation [SD]) unique raters in each period (median = 20).Concurrent validity was shown by Kendall τb = 0.45 (P < .0001) pairwise by combination of ratee and rater between the average supervision score and the average score on a 21-item evaluation completed by fellows in pain medicine. Concurrent validity also was shown by τb = 0.36 (P = .0002) pairwise by combination of ratee and rater between the average pain medicine supervision score and the average operating room supervision score completed by anesthesiology residents.Average supervision scores differed markedly among the 113 raters (η = 0.485; CI, 0.447-0.490). Pairings of ratee and rater were nonrandom (Cramér V = 0.349; CI, 0.252-0.446).Mixed effects logistic regression was performed with rater leniency as covariates and the dependent variable being an average score equaling the maximum 4 vs <4. There were 3 of 13 ratees with significantly more averages <4 than the other ratees, based on P < .01 criterion; that is, their supervision was reliably rated as below average. There were 3 of 13 different ratees who provided supervision reliably rated as above average.Raters did not report higher supervision scores when they had the opportunity to perform more interventional pain procedures. CONCLUSIONS: Evaluations of pain medicine clinical faculty are required. As found when used for evaluating operating room anesthesiologists, a supervision scale has excellent internal consistency, achievable reliability using 1-year periods of data, concurrent validity with other ratings, and the ability to differentiate among ratees. However, to be reliable, routinely collected supervision scores must be adjusted for rater leniency.

Association between leniency of anesthesiologists when evaluating certified registered nurse anesthetists and when evaluating didactic lectures.

Daily evaluations of certified registered nurse anesthetists' (CRNAs') work habits by anesthesiologists should be adjusted for rater leniency. The current study tested the hypothesis that there is a pairwise association by rater between leniencies of evaluations of CRNAs' daily work habits and of didactic lectures. The historical cohorts were anesthesiologists' evaluations over 53 months of CRNAs' daily work habits and 65 months of didactic lectures by visiting professors and faculty. The binary endpoints were the Likert scale scores for all 6 and 10 items, respectively, equaling the maximums of 5 for all items, or not. Mixed effects logistic regression estimated the odds of each ratee performing above or below average adjusted for rater leniency. Bivariate errors in variables least squares linear regression estimated the association between the leniency of the anesthesiologists' evaluations of work habits and didactic lectures. There were 29/107 (27%) raters who were more severe in their evaluations of CRNAs' work habits than other anesthesiologists (two-sided P < 0.01); 34/107 (32%) raters were more lenient. When evaluating lectures, 3/81 (4%) raters were more severe and 8/81 (10%) more lenient. Among the 67 anesthesiologists rating both, leniency (or severity) for work habits was not associated with that for lectures (P = 0.90, unitless slope between logits 0.02, 95% confidence interval -0.34 to 0.30). Rater leniency is of large magnitude when making daily clinical evaluations, even when using a valid and psychometrically reliable instrument. Rater leniency was context dependent, not solely a reflection of raters' personality or rating style.

Anesthetic Management of Emergency Endovascular Thrombectomy for Acute Ischemic Stroke, Part 1: Patient Characteristics, Determinants of Effectiveness, and Effect of Blood Pressure on Outcome.

In the United States, stroke ranks fifth among all causes of death and is the leading cause of serious long-term disability. The 2018 American Heart Association stroke care guidelines consider endovascular thrombectomy to be the standard of care for patients who have acute ischemic stroke in the anterior circulation when arterial puncture can be made within 6 hours of symptom onset or within 6-24 hours of symptom onset when specific eligibility criteria are satisfied. The aim of this 2-part review is to provide practical perspective on the clinical literature regarding anesthesia care of patients treated with endovascular thrombectomy. Part 1 (this article) reviews the development of endovascular thrombectomy and the determinants of endovascular thrombectomy effectiveness irrespective of method of anesthesia. The first aim of part 1 is to explain why rapid workflow and maintenance of blood pressure are necessary to help support the ischemic brain until, as a result of endovascular thrombectomy, reperfusion is accomplished. The second aim of part 1, understanding the nonanesthesia factors determining endovascular thrombectomy effectiveness, is necessary to identify numerous biases present in observational reports regarding anesthesia for endovascular thrombectomy. With this background, in part 2 (the companion to this article), the observational literature is briefly summarized, largely to identify its weaknesses, but also to develop hypotheses derived from it that have been recently tested in 3 randomized clinical trials of sedation versus general anesthesia for endovascular thrombectomy. In part 2, these 3 trials are reviewed both from a functional outcomes perspective (meta-analysis) and a methodological perspective, providing specifics regarding anesthesia and hemodynamic management. Part 2 concludes with a pragmatic approach to anesthesia decision making (sedation versus general anesthesia) and acute phase anesthesia management of patients treated with endovascular thrombectomy.

Anesthetic Management of Emergency Endovascular Thrombectomy for Acute Ischemic Stroke, Part 2: Integrating and Applying Observational Reports and Randomized Clinical Trials.

The 2018 American Heart Association stroke care guidelines consider endovascular thrombectomy to be the standard of care for patients who have acute ischemic stroke in the anterior circulation when arterial puncture can be made: (1) within 6 h of symptom onset; or (2) within 6-24 h of symptom onset when specific eligibility criteria are satisfied. The aim of this 2-part review is to provide practical perspective on the clinical literature regarding anesthesia care of endovascular thrombectomy patients. In the preceding companion article (part 1), the rationale for rapid workflow and maintenance of blood pressure before reperfusion were reviewed. Also in part 1, the key patient and procedural factors determining endovascular thrombectomy effectiveness were identified. In this article (part 2), the observational literature regarding anesthesia for endovascular thrombectomy is summarized briefly, largely to identify its numerous biases, but also to develop hypotheses regarding sedation versus general anesthesia pertaining to workflow, hemodynamic management, and intra- and post-endovascular thrombectomy adverse events. These hypotheses underlie the conduct and outcome measures of 3 recent randomized clinical trials of sedation versus general anesthesia for endovascular thrombectomy. A meta-analysis of functional outcomes from these 3 trials show, when managed according to trial protocols, sedation and general anesthesia result in outcomes that are not significantly different. Details regarding anesthesia and hemodynamic management from these 3 trials are provided. This article concludes with a pragmatic approach to real-time anesthesia decision-making (sedation versus general anesthesia) and the goals and methods of acute phase anesthesia management of endovascular thrombectomy patients.

Perioperative Temperature Measurement Considerations Relevant to Reporting Requirements for National Quality Programs Using Data From Anesthesia Information Management Systems.

BACKGROUND: Perioperative hypothermia may increase the incidences of wound infection, blood loss, transfusion, and cardiac morbidity. US national quality programs for perioperative normothermia specify the presence of at least 1 "body temperature" ≥35.5°C during the interval from 30 minutes before to 15 minutes after the anesthesia end time. Using data from 4 academic hospitals, we evaluated timing and measurement considerations relevant to the current requirements to guide hospitals wishing to report perioperative temperature measures using electronic data sources. METHODS: Anesthesia information management system databases from 4 hospitals were queried to obtain intraoperative temperatures and intervals to the anesthesia end time from discontinuation of temperature monitoring, end of surgery, and extubation. Inclusion criteria included age >16 years, use of a tracheal tube or supraglottic airway, and case duration ≥60 minutes. The end-of-case temperature was determined as the maximum intraoperative temperature recorded within 30 minutes before the anesthesia end time (ie, the temperature that would be used for reporting purposes). The fractions of cases with intervals >30 minutes between the last intraoperative temperature and the anesthesia end time were determined. RESULTS: Among the hospitals, averages (binned by quarters) of 34.5% to 59.5% of cases had intraoperative temperature monitoring discontinued >30 minutes before the anesthesia end time. Even if temperature measurement had been continued until extubation, averages of 5.9% to 20.8% of cases would have exceeded the allowed 30-minute window. Averages of 8.9% to 21.3% of cases had end-of-case intraoperative temperatures <35.5°C (ie, a quality measure failure). CONCLUSIONS: Because of timing considerations, a substantial fraction of cases would have been ineligible to use the end-of-case intraoperative temperature for national quality program reporting. Thus, retrieval of postanesthesia care unit temperatures would have been necessary. A substantive percentage of cases had end-of-case intraoperative temperatures below the 35.5°C threshold, also requiring postoperative measurement to determine whether the quality measure was satisfied. Institutions considering reporting national quality measures for perioperative normothermia should consider the technical and logistical issues identified to achieve a high level of compliance based on the specified regulatory language.

Operating Room Anesthesia Subspecialization Is Not Associated With Significantly Greater Quality of Supervision of Anesthesia Residents and Nurse Anesthetists.

BACKGROUND: Supervision of anesthesia residents and nurse anesthetists is a major responsibility of faculty anesthesiologists. The quality of their supervision can be assessed quantitatively by the anesthesia residents and nurse anesthetists. Supervision scores are an independent measure of the contribution of the anesthesiologist to patient care. We evaluated the association between quality of supervision and level of specialization of anesthesiologists. METHODS: We used two 6-month periods, one with no feedback to anesthesiologists of the residents' and nurse anesthetists' evaluations, and the other with feedback. Supervision scores provided by residents and nurse anesthetists were considered separately. Sample sizes among the 4 combinations ranged from n = 51 to n = 62 University of Iowa faculty. For each supervising anesthesiologist and 6-month period, we calculated the proportion of anesthetic cases attributable to each anesthesia Current Procedural Terminology code. The sum of the square of the proportions, a measurement of diversity, is known as the Herfindahl index. The inverse of this index represents the effective number of common procedures. The diversity (degree of specialization) of each faculty anesthesiologist was measured attributing each case to: (1) the anesthesiologist who supervised for the longest total period of time, (2) the anesthesiologist who started the case, or (3) the anesthesiologist who started the case, limited to cases started during "regular hours" (defined as nonholiday Monday to Friday, 07:00 AM to 02:59 PM). Inferential analysis was performed using bivariate-weighted least-squares regression. RESULTS: The point estimates of all 12 slopes were in the direction of greater specialization of practice of the evaluated faculty anesthesiologist being associated with significantly lower supervision scores. Among supervision scores provided by nurse anesthetists, the association was statistically significant for the third of the 6-month periods under the first and second ways of attributing the cases (uncorrected P < .0001). However, the slopes of the relationships were all small (eg, 0.109 ± 0.025 [SE] units on the 4-point supervision scale for a change of 10 common procedures). Among supervision scores provided by anesthesia residents, the association was statistically significant during the first period for all 3 ways of attributing the case (uncorrected P < .0001). However, again, the slopes were small (eg, 0.127 ± 0.027 units for a change of 10 common procedures). CONCLUSIONS: Greater clinical specialization of faculty anesthesiologists was not associated with meaningful improvements in quality of clinical supervision.

Content analysis of resident evaluations of faculty anesthesiologists: supervision encompasses some attributes of the professionalism core competency.

BACKGROUND: Anesthesiology departments need an instrument with which to assess practicing anesthesiologists' professionalism. The purpose of this retrospective analysis of the content of a cohort of resident evaluations of faculty anesthesiologists was to investigate the relationship between a clinical supervision scale and the multiple attributes of professionalism. METHODS: From July 1, 2013 to the present, our department has utilized the de Oliveira Filho unidimensional nine-item supervision scale to assess the quality of clinical supervision of residents provided by our anesthesiologists. The "cohort" we examined included all 13,664 resident evaluations of all faculty anesthesiologists from July 1, 2013 through December 31, 2015, including 1,387 accompanying comments. Words and phrases associated with the core competency of professionalism were obtained from previous studies, and the supervision scale was analyzed for the presence of these words and phrases. RESULTS: The supervision scale assesses some attributes of anesthesiologists' professionalism as well as patient care and procedural skills and interpersonal and communication skills. The comments that residents provided with the below-average supervision scores included attributes of professionalism, although numerous words and phrases related to professionalism were not present in any of the residents' comments. CONCLUSIONS: The de Oliveira Filho clinical supervision scale includes some attributes of anesthesiologists' professionalism. The core competency of professionalism, however, is multidimensional, and the supervision scale and/or residents' comments did not address many of the other established attributes of professionalism.

Measurement of faculty anesthesiologists' quality of clinical supervision has greater reliability when controlling for the leniency of the rating anesthesia resident: a retrospective cohort study.

BACKGROUND: Our department monitors the quality of anesthesiologists' clinical supervision and provides each anesthesiologist with periodic feedback. We hypothesized that greater differentiation among anesthesiologists' supervision scores could be obtained by adjusting for leniency of the rating resident. METHODS: From July 1, 2013 to December 31, 2015, our department has utilized the de Oliveira Filho unidimensional nine-item supervision scale to assess the quality of clinical supervision provided by faculty as rated by residents. We examined all 13,664 ratings of the 97 anesthesiologists (ratees) by the 65 residents (raters). Testing for internal consistency among answers to questions (large Cronbach's alpha > 0.90) was performed to rule out that one or two questions accounted for leniency. Mixed-effects logistic regression was used to compare ratees while controlling for rater leniency vs using Student t tests without rater leniency. RESULTS: The mean supervision scale score was calculated for each combination of the 65 raters and nine questions. The Cronbach's alpha was very large (0.977). The mean score was calculated for each of the 3,421 observed combinations of resident and anesthesiologist. The logits of the percentage of scores equal to the maximum value of 4.00 were normally distributed (residents, P = 0.24; anesthesiologists, P = 0.50). There were 20/97 anesthesiologists identified as significant outliers (13 with below average supervision scores and seven with better than average) using the mixed-effects logistic regression with rater leniency entered as a fixed effect but not by Student's t test. In contrast, there were three of 97 anesthesiologists identified as outliers (all three above average) using Student's t tests but not by logistic regression with leniency. The 20 vs 3 was significant (P < 0.001). CONCLUSIONS: Use of logistic regression with leniency results in greater detection of anesthesiologists with significantly better (or worse) clinical supervision scores than use of Student's t tests (i.e., without adjustment for rater leniency).

Work Habits Are Valid Components of Evaluations of Anesthesia Residents Based on Faculty Anesthesiologists' Daily Written Comments About Residents.

BACKGROUND: In our department, faculty anesthesiologists routinely evaluate the resident physicians with whom they worked in an operative setting the day before, providing numerical scores to questions. The faculty can also enter a written comment if so desired. Because residents' work habits are important to anesthesiology program directors, and work habits can improve with feedback, we hypothesized that faculty comments would include the theme of the anesthesia resident's work habits. METHODS: We analyzed all 6692 faculty comments from January 1, 2011, to June 30, 2015. We quantified use of the theme of Dannefer et al.'s work habit scale, specifically the words and phrases in the scale, and synonyms to the words. RESULTS: Approximately half (50.7% [lower 99.99% confidence limit, 48.4%]) of faculty comments contained the theme of work habits. Multiple sensitivity analyses were performed excluding individual faculty, residents, and words. The lower confidence limits for comments containing the theme were each >42.7%. CONCLUSIONS: Although faculty anesthesiologists completed (numerical) questions based on the American College of Graduate Medical Education competencies to evaluate residents, an important percentage of written comments included the theme of work habits. The implication is that the theme has validity as one component of the routine evaluation of anesthesia residents.

Written Comments Made by Anesthesia Residents When Providing Below Average Scores for the Supervision Provided by the Faculty Anesthesiologist.

BACKGROUND: Anesthesia residents in our department evaluate the supervision provided by the faculty anesthesiologist with whom they worked the previous day. What advice managers can best provide to the faculty who receive below-average supervision scores is unknown. METHODS: The residents provided numerical answers (1 "never," 2 "rarely," 3 "frequently," or 4 "always") to each of the 9 supervision questions, resulting in a total supervision score. A written comment could also be provided. RESULTS: Over 2.5 years, the response rate to requests for evaluation was 99.1%. There were 13,664 evaluations of 76 faculty including 1387 comments. There were 25 evaluations with a comment of disrespectful behavior. For all 25, the question evaluating whether "the faculty treated me respectfully" was answered <4 (i.e., not "always"). The supervision scores were less than for the other evaluations with comments (P < 0.0001). Each increase in the faculty's number of comments of being disrespectful was associated with a lesser mean score (P = 0.0002). A low supervision score (<3.00; i.e., less than "frequent") had an odds ratio of 85 for disrespectful faculty behavior (P < 0.0001). The predictive value of the supervision score not being low for absence of a comment of disrespectful behavior was 99%. That finding was especially useful because 94% of scores below average (<3.80) were not low (≥3.00). There were 6 evaluations with a comment of insufficient faculty presence. Those evaluations had lesser scores than the other evaluations with comments (P < 0.0001). The 6 faculty with 1 such comment had lesser mean scores than the other faculty (P = 0.0071). There were 34 evaluations with a comment about poor-quality teaching. The evaluations related to poor teaching had lesser scores than the other evaluations with comments (P < 0.0001). The faculty who each received such a comment had lesser mean scores than the other faculty (P < 0.0001). Each increase in the faculty's number of comments of poor-quality teaching was associated with a lesser mean score (P = 0.0002). The 9 supervision questions were internally consistent (Cronbach α = 0.948). A faculty with a comment about poor-quality teaching had significant odds of also having a comment about insufficient presence (P = 0.0044). A comment with negative sentiment had significant odds of being about poor-quality teaching rather than being about insufficient presence (odds ratio, 6.00; P < 0.0001). CONCLUSIONS: A faculty who has insufficient presence cannot be providing good teaching. Furthermore, there was negligible correlation between supervision scores and faculty clinical assignments. Thus, insufficient faculty presence accounted for a small proportion of below-average supervision scores and low-quality supervision. Furthermore, scores ≥3 have a predictive value for the absence of disrespectful behavior ≅99%. Approximately 94% of the faculty supervision scores that were below average were still ≥3. Consequently, for the vast majority of the faculty-resident-days, quality of teaching distinguished between below- versus above-average supervision scores. This result is consistent with our prior finding of a strong correlation between 6-month supervision scores and assessments of teaching effectiveness. Taken together, when individual faculty anesthesiologists are counseled about their clinical supervision scores, the attribute to emphasize is quality of clinical teaching.

Quantifying the Diversity and Similarity of Surgical Procedures Among Hospitals and Anesthesia Providers.

In this Statistical Grand Rounds, we review methods for the analysis of the diversity of procedures among hospitals, the activities among anesthesia providers, etc. We apply multiple methods and consider their relative reliability and usefulness for perioperative applications, including calculations of SEs. We also review methods for comparing the similarity of procedures among hospitals, activities among anesthesia providers, etc. We again apply multiple methods and consider their relative reliability and usefulness for perioperative applications. The applications include strategic analyses (e.g., hospital marketing) and human resource analytics (e.g., comparisons among providers). Measures of diversity of procedures and activities (e.g., Herfindahl and Gini-Simpson index) are used for quantification of each facility (hospital) or anesthesia provider, one at a time. Diversity can be thought of as a summary measure. Thus, if the diversity of procedures for 48 hospitals is studied, the diversity (and its SE) is being calculated for each hospital. Likewise, the effective numbers of common procedures at each hospital can be calculated (e.g., by using the exponential of the Shannon index). Measures of similarity are pairwise assessments. Thus, if quantifying the similarity of procedures among cases with a break or handoff versus cases without a break or handoff, a similarity index represents a correlation coefficient. There are several different measures of similarity, and we compare their features and applicability for perioperative data. We rely extensively on sensitivity analyses to interpret observed values of the similarity index.

Diversity and Similarity of Anesthesia Procedures in the United States During and Among Regular Work Hours, Evenings, and Weekends.

BACKGROUND: Anesthesiologists providing care during off hours (ie, weekends or holidays, or cases started during the evening or late afternoon) are more likely to care for patients at greater risk of sustaining major adverse events than when they work during regular hours (eg, Monday through Friday, from 7:00 AM to 2:59 PM). We consider the logical inconsistency of using subspecialty teams during regular hours but not during weekends or evenings. METHODS: We analyzed data from the Anesthesia Quality Institute's National Anesthesia Clinical Outcomes Registry (NACOR). Among the hospitals in the United States, we estimated the average number of common types of anesthesia procedures (ie, diversity measured as inverse of Herfindahl index), and the average difference in the number of common procedures between 2 off-hours periods (regular hours versus weekends, and regular hours versus evenings). We also used NACOR data to estimate the average similarity in the distributions of procedures between regular hours and weekends and between regular hours and evenings in US facilities. Results are reported as mean ± standard error of the mean among 399 facilities nationwide with weekend cases. RESULTS: The distributions of common procedures were moderately similar (ie, not large, <.8) between regular hours and evenings (similarity index .59 ± .01) and between regular hours and weekends (similarity index, .55 ± .02). For most facilities, the number of common procedures differed by <5 procedures between regular hours and evenings (74.4% of facilities, P < .0001) and between regular hours and weekends (64.7% of facilities, P < .0001). The average number of common procedures was 13.59 ± .12 for regular hours, 13.12 ± .13 for evenings, and 9.43 ± .13 for weekends. The pairwise differences by facility were .13 ± .07 procedures (P = .090) between regular hours and evenings and 3.37 ± .12 procedures (P < .0001) between regular hours and weekends. In contrast, the differences were -5.18 ± .12 and 7.59 ± .13, respectively, when calculated using nationally pooled data. This was because the numbers of common procedures were 32.23 ± .05, 37.41 ± .11, and 24.64 ± .12 for regular hours, evenings, and weekends, respectively (ie, >2x the number of common procedures calculated by facility). CONCLUSIONS: The numbers of procedures commonly performed at most facilities are fewer in number than those that are commonly performed nationally. Thus, decisions on anesthesia specialization should be based on quantitative analysis of local data rather than national recommendations using pooled data. By facility, the number of different procedures that take place during regular hours and off hours (diversity) is essentially the same, but there is only moderate similarity in the procedures performed. Thus, at many facilities, anesthesiologists who work principally within a single specialty during regular work hours will likely not have substantial contemporary experience with many procedures performed during off hours.

Intubation Biomechanics: Laryngoscope Force and Cervical Spine Motion during Intubation in Cadavers-Cadavers versus Patients, the Effect of Repeated Intubations, and the Effect of Type II Odontoid Fracture on C1-C2 Motion.

BACKGROUND: The aims of this study are to characterize (1) the cadaver intubation biomechanics, including the effect of repeated intubations, and (2) the relation between intubation force and the motion of an injured cervical segment. METHODS: Fourteen cadavers were serially intubated using force-sensing Macintosh and Airtraq laryngoscopes in random order, with simultaneous cervical spine motion recorded with lateral fluoroscopy. Motion of the C1-C2 segment was measured in the intact and injured state (type II odontoid fracture). Injured C1-C2 motion was proportionately corrected for changes in intubation forces that occurred with repeated intubations. RESULTS: Cadaver intubation biomechanics were comparable with those of patients in all parameters other than C2-C5 extension. In cadavers, intubation force (set 2/set 1 force ratio = 0.61; 95% CI, 0.46 to 0.81; P = 0.002) and Oc-C5 extension (set 2 - set 1 difference = -6.1 degrees; 95% CI, -11.4 to -0.9; P = 0.025) decreased with repeated intubations. In cadavers, C1-C2 extension did not differ (1) between intact and injured states; or (2) in the injured state, between laryngoscopes (with and without force correction). With force correction, in the injured state, C1-C2 subluxation was greater with the Airtraq (mean difference 2.8 mm; 95% CI, 0.7 to 4.9 mm; P = 0.004). CONCLUSIONS: With limitations, cadavers may be clinically relevant models of intubation biomechanics and cervical spine motion. In the setting of a type II odontoid fracture, C1-C2 motion during intubation with either the Macintosh or the Airtraq does not appear to greatly exceed physiologic values or to have a high likelihood of hyperextension or direct cord compression.

Quality of Supervision as an Independent Contributor to an Anesthesiologist's Individual Clinical Value.

BACKGROUND: Although the clinical (operating room) production of individual anesthesiologists has been measured in multiple related ways (e.g., hours of direct clinical care), the same is not true for the quality of that effort. In our study, we consider the quality of clinical supervision provided by anesthesiologists who are supervising anesthesia residents and nurse anesthetists. The quality of the daily supervision can be measured reliably and validly using the scale developed by de Oliveira Filho et al. If clinical production and supervisory quality were not positively correlated, then it would be important for departments to measure the quality of clinical supervision because, essentially, the clinical value provided by an anesthesiologist would be correlated with, but not necessarily proportional to, their clinical hours. METHODS: Our department sends daily e-mail requests to anesthesia residents and nurse anesthetists to evaluate the supervision provided by each anesthesiologist with whom they worked the previous day in an operating room setting. We compared anesthesiologists' clinical activity (total operating room hours) and supervision scores obtained during the first (July 1, 2013 to December 31, 2013) and last (July 1, 2014 to December 31, 2014) of 3 consecutive 6-month periods. During the first 6 months, anesthesiologists received no feedback regarding the supervision scores. During the last 6 months, there was feedback to all anesthesiologists regarding their individual supervision scores and comments provided by residents (during the preceding 6 months) and nurse anesthetists (during the preceding 12 months). RESULTS: Anesthesiologists' mean supervision scores were not positively correlated with their total (weekly) hours of clinical activity. For the first 6 months, the correlations were r = -0.18 among scores provided by residents (P = 0.92 for positive correlation, N = 57 anesthesiologists) and r = -0.04 among scores provided by nurse anesthetists (P = 0.70, N = 61). For the last 6 months, the correlations were r = -0.28 (P = 0.98) and r = -0.10 (P = 0.79), respectively. Pairwise by anesthesiologist, the mean supervision scores provided by residents increased by 0.08 ± 0.01 points (P < 0.0001, N = 44). The mean supervision scores provided by nurse anesthetists increased by 0.28 ± 0.02 points (P < 0.0001, N = 49). CONCLUSIONS: When anesthesiologists supervise anesthesia residents and nurse anesthetists, the amount of clinical work performed and the quality of the supervision provided do not necessarily follow one another. Thus, faculty supervision scores serve as an independent measure of the contribution of an individual anesthesiologist to the care of the patient. Furthermore, when supervision quality is monitored and feedback is provided to anesthesiologists, quality can increase. The results suggest that anesthesiology department managers should not only be monitoring (and perhaps reporting) the quality of their departments' level of supervision, but also establishing processes so that individual anesthesiologists can learn about the quality of supervision they provide.

Anesthesia residents' global (departmental) evaluation of faculty anesthesiologists' supervision can be less than their average evaluations of individual anesthesiologists.

BACKGROUND: Faculty anesthesiologists' supervision of anesthesiology residents is required for both postgraduate medical education and billing compliance. Previously, using the de Oliveira Filho et al. supervision question set, De Oliveira et al. found that residents who reported mean department-wide supervision scores <3.0 ("frequent") reported a significantly more frequent occurrence of mistakes with negative consequences to patients, as well as medication errors. In our department, residents provide daily evaluations of the supervision received by individual faculty. Using a survey study, we compared relationships between residents' daily supervision scores for individual faculty anesthesiologists and residents' supervision scores for the entire department (comprised these faculty). METHODS: We studied all anesthesiology residents in clinical years 1, 2, and 3 (i.e., neither in the "base year" nor in fellowship). There were daily evaluations of individual faculty supervision of operative anesthesia for 36 weeks. Residents clicked a hyperlink on the invitation e-mail taking them to a secure Web page to provide their global (departmental) assessment of faculty supervision. We calculated the ratio of each resident's global (departmental) faculty supervision score (i.e., mean among 9 questions × 1 evaluation) to the same resident's daily evaluations of individual faculty (i.e., mean among 9 questions × many evaluations). RESULTS: All 39 of 39 residents chose to participate. The mean departmental supervision score was significantly less (P < 0.0001) than the mean of individual faculty scores. The median ratio of scores was 86% (95% confidence interval, 83%-89%). Kendall's rank correlation between global and (mean) individual faculty scores was τb = 0.34 ± 0.11 (P = 0.0032). The ratios were uniformly distributed (P = 0.64) between the observed minimums and maximums; were not correlated with the mean value of individual faculty scores previously provided by each resident (P = 0.64); were not correlated with the number of individual faculty evaluations previously provided by each resident (P = 0.49); and did not differ among the first, second, or third year residents (P = 0.37). CONCLUSIONS: Residents' perceptions of overall (departmental) faculty supervision were less than overall averages of their perceptions of individual faculty supervision. This should be considered when interpreting national survey results (e.g., of patient safety), residency program evaluations, and individual faculty anesthesiologist performance.