Michelle Housey

Intraoperative Lung-Protective Ventilation Trends and Practice Patterns: A Report from the Multicenter Perioperative Outcomes Group.

BACKGROUND:The use of an intraoperative lung-protective ventilation strategy through tidal volume (TV) size reduction and positive end-expiratory pressure (PEEP) has been increasingly investigated. In this article, we describe the current intraoperative lung-protective ventilation practice patterns and trends. METHODS:By using the Multicenter Perioperative Outcomes Group database, we identified all general endotracheal anesthetics from January 2008 through December 2013 at 10 institutions. The following data were calculated: (1) percentage of patients receiving TV > 10 mL/kg predicted body weight (PBW); (2) median initial and overall TV in mL/kg PBW and; (3) percentage of patients receiving PEEP ≥ 5 cm H2O. The data were analyzed at 3-month intervals. Interinstitutional variability was assessed. RESULTS:A total of 330,823 patients met our inclusion criteria for this study. During the study period, the percentage of patients receiving TV > 10 mL/kg PBW was reduced for all patients (26% to 14%) and in the subpopulations of obese (41% to 25%), short stature (52% to 36%), and females (39% to 24%; all P values <0.001). There was a significant reduction in TV size (8.90–8.20 mL/kg PBW, P < 0.001). There was also a statistically significant but clinically irrelevant difference between initial and overall TV size (8.65 vs 8.63 mL/kg PBW, P < 0.001). Use of PEEP ≥ 5 cm H2O increased during the study period (25%–45%, P < 0.001). TV usage showed significant interinstitutional variability (P < 0.001). CONCLUSIONS:Although decreasing, a significant percentage of patients are ventilated with TV > 10 mL/kg PBW, especially if they are female, obese, or of short stature. The use of PEEP ≥ 5 cm H2O has increased significantly. Creating awareness of contemporary practice patterns and demonstrating the efficacy of lung-protective ventilation are still needed to optimize intraoperative ventilation.

Influence of Ventilation Strategies and Anesthetic Techniques on Regional Cerebral Oximetry in the Beach Chair Position: A Prospective Interventional Study with a Randomized Comparison of Two Anesthetics.

Background:Beach chair positioning during general anesthesia is associated with cerebral oxygen desaturation. Changes in cerebral oxygenation resulting from the interaction of inspired oxygen fraction (FIO2), end-tidal carbon dioxide (PETCO2), and anesthetic choice have not been fully evaluated in anesthetized patients in the beach chair position. Methods:This is a prospective interventional within-group study of patients undergoing shoulder surgery in the beach chair position that incorporated a randomized comparison between two anesthetics. Fifty-six patients were randomized to receive desflurane or total intravenous anesthesia with propofol. Following induction of anesthesia and positioning, FIO2 and minute ventilation were sequentially adjusted for all patients. Regional cerebral oxygenation (rSO2) was the primary outcome and was recorded at each of five set points. Results:While maintaining FIO2 at 0.3 and PETCO2 at 30 mmHg, there was a decrease in rSO2 from 68% (SD, 12) to 61% (SD, 12) (P < 0.001) following beach chair positioning. The combined interventions of increasing FIO2 to 1.0 and increasing PETCO2 to 45 mmHg resulted in a 14% point improvement in rSO2 to 75% (SD, 12) (P <0.001) for patients anesthetized in the beach chair position. There was no significant interaction effect of the anesthetic at the study intervention points. Conclusions:Increasing FIO2 and PETCO2 resulted in a significant increase in rSO2 that overcomes desaturation in patients anesthetized in the beach chair position and that appears independent of anesthetic choice.

Incidence and Prevalence of Systemic Lupus Erythematosus Among Arab and Chaldean Americans in Southeastern Michigan: The Michigan Lupus Epidemiology and Surveillance Program

OBJECTIVES We assessed the burden of systemic lupus erythematosus (SLE) among Arab and Chaldean Americans residing in southeast Michigan. METHODS For those meeting SLE criteria from the Michigan Lupus Epidemiology and Surveillance Registry, we determined Arab or Chaldean ethnicity by links with demographic data from birth certificates and with a database of Arab and Chaldean names. We compared prevalence and incidence of SLE for Arab and Chaldean Americans with estimates for non-Arab and non-Chaldean American Whites and Blacks. RESULTS We classified 54 individuals with SLE as Arab and Chaldean Americans. The age-adjusted incidence and prevalence estimates for Arab and Chaldean Americans were 7.6 and 62.6 per 100 000, respectively. Arab and Chaldean Americans had a 2.1-fold excess SLE incidence compared with non-Arab and non-Chaldean American Whites. Arab and Chaldean American women had both significantly higher incidence rates (5.0-fold increase) and prevalence estimates (7.4-fold increase) than did Arab and Chaldean American men. CONCLUSIONS Recognizing that Arab and Chaldean Americans experience different disease burdens from Whites is a first step toward earlier diagnosis and designing targeted interventions. Better methods of assigning ethnicity would improve research in this population.

Risk of Epidural Hematoma after Neuraxial Techniques in Thrombocytopenic Parturients : A Report from the Multicenter Perioperative Outcomes Group

Background: Thrombocytopenia has been considered a relative or even absolute contraindication to neuraxial techniques due to the risk of epidural hematoma. There is limited literature to estimate the risk of epidural hematoma in thrombocytopenic parturients. The authors reviewed a large perioperative database and performed a systematic review to further define the risk of epidural hematoma requiring surgical decompression in this population. Methods: The authors performed a retrospective cohort study using the Multicenter Perioperative Outcomes Group database to identify thrombocytopenic parturients who received a neuraxial technique and to estimate the risk of epidural hematoma. Patients were stratified by platelet count, and those requiring surgical decompression were identified. A systematic review was performed, and risk estimates were combined with those from the existing literature. Results: A total of 573 parturients with a platelet count less than 100,000 mm–3 who received a neuraxial technique across 14 institutions were identified in the Multicenter Perioperative Outcomes Group database, and a total of 1,524 parturients were identified after combining the data from the systematic review. No cases of epidural hematoma requiring surgical decompression were observed. The upper bound of the 95% CI for the risk of epidural hematoma for a platelet count of 0 to 49,000 mm–3 is 11%, for 50,000 to 69,000 mm–3 is 3%, and for 70,000 to 100,000 mm–3 is 0.2%. Conclusions: The number of thrombocytopenic parturients in the literature who received neuraxial techniques without complication has been significantly increased. The risk of epidural hematoma associated with neuraxial techniques in parturients at a platelet count less than 70,000 mm–3 remains poorly defined due to limited observations.

Intraoperative medications associated with hemodynamically significant anaphylaxis

STUDY OBJECTIVE To facilitate the identification of drugs and patient factors associated with hemodynamically significant anaphylaxis. DESIGN Using an existing database containing complete perioperative records, instances of hemodynamically significant anaphylaxis were identified using a physiologic and treatment-based screening algorithm. All cases were manually reviewed by 2 clinicians, with a third adjudicating disagreements, and confirmed cases were matched 3:1 with control cases. Intraoperative medications given in instances of hemodynamically significant anaphylaxis and patient risk factors were compared with control cases. SETTING University of Michigan Hospital, a large, tertiary care hospital. PATIENTS All adult patients undergoing surgery between January 1, 2004, and January 5, 2015. INTERVENTIONS None. MEASUREMENTS Incidence of hemodynamically significant anaphylaxis during anesthesia. Patient risk factors and intraoperative medications associated with hemodynamically significant anaphylaxis. MAIN RESULTS Hemodynamically significant anaphylaxis occurred in 55 of 461 986 cases (1 in 8400). Hemodynamically significant anaphylaxis occurred in 52 patients, with 1 patient experiencing 3 instances and another patient 2 instances. Only 1 drug was associated with an increased risk of hemodynamically significant anaphylaxis: protamine (odds ratio, 11.78; 95% confidence interval, 1.40-99.26; P=.0233). No category of drugs was associated with increased risk. Of patient risk factors, only personal history of anaphylaxis was associated with an increased risk (odds ratio, 77.1; 95% confidence interval, 10.46-567.69; P=<.0001). Postoperative follow-up and evaluation of patients were low at our institution. A serum tryptase level was sent in only 49% of cases, and 41% of levels were positive, an overall positive rate of 20% of cases. Following instances of hemodynamically significant anaphylaxis, only 29% of patients were seen and evaluated by an allergist at our institution. CONCLUSIONS Hemodynamically significant anaphylaxis is a rare complication of anesthesia, with an incidence consistent with the existing literature. Contrary to most existing literature, only protamine was associated with increased risk. A personal history of anaphylaxis appears to best predict risk of hemodynamically significant anaphylaxis.

A Survey of Simulation Utilization in Anesthesiology Residency Programs in the United States.

Given the evolution of competency-based education and evidence supporting the benefits of incorporating simulation into anesthesiology residency training, simulation will likely play an important role in the training and assessment of anesthesiology residents. Currently, there are little data available regarding the current status of simulation-based curricula across US residency programs. In this study, we assessed simulation-based training and assessment in US anesthesiology programs using a survey designed to elicit information regarding the type, frequency, and content of the simulation courses offered at the 132 Accreditation Council of Graduate Medical Education-certified anesthesiology training programs. The response rate for the survey was 66%. Although most of the responding programs offered simulation-based courses for interns and residents and during CA-1 orientation, the curriculum varied greatly among programs. Approximately 40% of responding programs use simulation for resident assessment and remediation. The majority of responding programs favored standard simulation-based training as part of residency training (89%), and the most common perceived obstacles to doing so were time, money, and human resources. The results from this survey highlight that there are currently large variations in simulation-based training and assessment among training programs. It also confirms that many program directors feel that standardizing some components of simulation-based education and assessment would be beneficial. Given the positive impact simulation has on skill retention and operating room preparedness, it may be worthwhile to consider developing a standard curriculum.

Alarm Limits for Intraoperative Drug Infusions: A Report from the Multicenter Perioperative Outcomes Group

BACKGROUND: Continuous medication infusions are commonly used during surgical procedures. Alarm settings for infusion pumps are considered important for patient safety, but limits are not created in a standardized manner from actual usage data. We estimated 90th and 95th percentile infusion rates from a national database for potential use as upper limit alarm settings. METHODS: We extracted infusion rate data from 17 major hospitals using intraoperative records provided by Multicenter Perioperative Outcomes Group for adult surgery between 2008 and 2014. Seven infusions were selected for study: propofol, remifentanil, dexmedetomidine, norepinephrine, phenylephrine, nitroglycerin, and esmolol. Each dosage entry for an infusion during a procedure was included. We estimated the 50th, 90th, and 95th percentile levels for each infusion across institutions, and performed quantile regression to examine factors that might affect the percentiles rates, such as use in general anesthesia versus sedation. RESULTS: The median 90th and 95th percentile infusion rates (with interquartile range) for propofol were 150 (140–150) and 170 (150–200) &mgr;g/kg/min. Quantile regression demonstrated higher 90th and 95th percentile rates during sedation for gastrointestinal endoscopy than for all surgical procedures performed under general anesthesia. For selected vasoactive medications, the corresponding median 90th and 95th percentile rates (with interquartile range) were norepinephrine 14.0 (9.8–18.1) and 18.3 (12.6–23.9) &mgr;g/min, and phenylephrine 60 (55–80) and 80 (75–100) &mgr;g/min. CONCLUSIONS: Alarm settings based on infusion rate percentile limits would be triggered at predictable rates; ie, the 95th percentile would be exceeded and an alarm sounded during 1 in 20 infusion rate entries. As a result, institutions could establish pump alarm settings consistent with desired alarm frequency using their own or externally validated usage data. Further study will be needed to determine the optimal percentile for infusion alarm settings.

Assessing anesthesiology residents’ out-of-the-operating-room (OOOR) emergent airway management

BackgroundAt many academic institutions, anesthesiology residents are responsible for managing emergent intubations outside of the operating room (OOOR), with complications estimated to be as high as 39%. In order to create an OOOR training curriculum, we evaluated residents’ familiarity with the content and correct adherence to the American Society of Anesthesiologists’ Difficult Airway Algorithm (ASA DAA).MethodsResidents completed a pre-simulation multiple-choice survey measuring their understanding and use of the DAA. Residents then managed an emergent, difficult OOOR intubation in the simulation center, where two trained reviewers assessed performance using checklists. Post-simulation, the residents completed a survey rating their behaviors during the simulation. The primary outcome was comprehension and adherence to the DAA as assessed by survey responses and behavior in the simulation.ResultsSixty-three residents completed both surveys and the simulation. Post-survey responses indicated a shift toward decreased self-perceived familiarity with the DAA content compared to pre-survey responses. During the simulation, 22 (35%) residents were unsuccessful with intubation. Of these, 46% placed an LMA and 46% prepared for cricothyroidotomy. Nineteen residents did not attempt intubation. Of these, only 31% considered LMA placement, and 26% initiated cricothyroidotomy.ConclusionsMany anesthesiology residency training programs permit resident autonomy in managing emergent intubations OOOR. Residents self-reported familiarity with the content of and adherence to the DAA was higher than that observed during the simulation. Curriculum focused on comprehension of the DAA, as well as improving communication with higher-level physicians and specialists, may improve outcomes during OOORs.

Maternal leukocytosis after antenatal corticosteroid administration: a systematic review and meta-analysis*

Abstract Although it is known that corticosteroid administration causes leukocytosis, the magnitude and length of time this leukocytosis persists is unknown during pregnancy. This study aimed to establish the expected range of maternal leukocytosis in healthy pregnant women at risk for preterm delivery after antenatal corticosteroid administration. PubMed, Embase and ClinicalTrials.gov were searched to identify the studies in healthy women at risk for preterm delivery without signs of clinical infection that reported white blood cell values preceding and after antenatal corticosteroid administration. The inverse variance weighting technique was used to calculate the weighted means and the standard deviation from the mean for each time period. Six studies met inclusion criteria and included 524 patients and 1406 observations. Mean ± standard deviation maternal white blood cell count values prior to antenatal corticosteroid administration and up to 24, 48, 72 and 96 hours after corticosteroid administration were 10.4 ± 2.4, 13.6 ± 3.6, 12.1 ± 3.0, 11.5 ± 2.9 and 11.1 ± 2.5 × 109/L, respectively. Leukocytosis in healthy, non-infected women is expected to peak 24 hours after antenatal corticosteroid administration and the magnitude of increase is small. Impact statement What is already known on this subject: While it is well known that administration of antenatal corticosteroids causes leukocytosis, it is currently unknown the magnitude and length of time the leukocytosis persists. What the results of this study add: This study establishes the expected range and the temporal progression and regression with antenatal corticosteroid administration in healthy pregnant women at risk for preterm delivery without clinical signs of infection. What the implications are of these findings for clinical practice and/or further research: Clinicians may wish to consider further investigation into the clinical cause, whether infectious or non-infectious, for absolute values and changes outside this range. Graphical Abstract