A Lower Tidal Volume Regimen during One-lung Ventilation for Lung Resection Surgery Is Not Associated with Reduced Postoperative Pulmonary Complications.

BACKGROUND: Protective ventilation may improve outcomes after major surgery. However, in the context of one-lung ventilation, such a strategy is incompletely defined. The authors hypothesized that a putative one-lung protective ventilation regimen would be independently associated with decreased odds of pulmonary complications after thoracic surgery. METHODS: The authors merged Society of Thoracic Surgeons Database and Multicenter Perioperative Outcomes Group intraoperative data for lung resection procedures using one-lung ventilation across five institutions from 2012 to 2016. They defined one-lung protective ventilation as the combination of both median tidal volume 5 ml/kg or lower predicted body weight and positive end-expiratory pressure 5 cm H2O or greater. The primary outcome was a composite of 30-day major postoperative pulmonary complications. RESULTS: A total of 3,232 cases were available for analysis. Tidal volumes decreased modestly during the study period (6.7 to 6.0 ml/kg; P < 0.001), and positive end-expiratory pressure increased from 4 to 5 cm H2O (P < 0.001). Despite increasing adoption of a "protective ventilation" strategy (5.7% in 2012 vs. 17.9% in 2016), the prevalence of pulmonary complications did not change significantly (11.4 to 15.7%; P = 0.147). In a propensity score matched cohort (381 matched pairs), protective ventilation (mean tidal volume 6.4 vs. 4.4 ml/kg) was not associated with a reduction in pulmonary complications (adjusted odds ratio, 0.86; 95% CI, 0.56 to 1.32). In an unmatched cohort, the authors were unable to define a specific alternative combination of positive end-expiratory pressure and tidal volume that was associated with decreased risk of pulmonary complications. CONCLUSIONS: In this multicenter retrospective observational analysis of patients undergoing one-lung ventilation during thoracic surgery, the authors did not detect an independent association between a low tidal volume lung-protective ventilation regimen and a composite of postoperative pulmonary complications.

Considerations for Integration of Perioperative Electronic Health Records Across Institutions for Research and Quality Improvement: The Approach Taken by the Multicenter Perioperative Outcomes Group.

Use of the electronic health record (EHR) has become a routine part of perioperative care in the United States. Secondary use of EHR data includes research, quality, and educational initiatives. Fundamental to secondary use is a framework to ensure fidelity, transparency, and completeness of the source data. In developing this framework, competing priorities must be considered as to which data sources are used and how data are organized and incorporated into a useable format. In assembling perioperative data from diverse institutions across the United States and Europe, the Multicenter Perioperative Outcomes Group (MPOG) has developed methods to support such a framework. This special article outlines how MPOG has approached considerations of data structure, validation, and accessibility to support multicenter integration of perioperative EHRs. In this multicenter practice registry, MPOG has developed processes to extract data from the perioperative EHR; transform data into a standardized format; and validate, deidentify, and transfer data to a secure central Coordinating Center database. Participating institutions may obtain access to this central database, governed by quality and research committees, to inform clinical practice and contribute to the scientific and clinical communities. Through a rigorous and standardized approach to ensure data integrity, MPOG enables data to be usable for quality improvement and advancing scientific knowledge. As of March 2019, our collaboration of 46 hospitals has accrued 10.7 million anesthesia records with associated perioperative EHR data across heterogeneous vendors. Facilitated by MPOG, each site retains access to a local repository containing all site-specific perioperative data, distinct from source EHRs and readily available for local research, quality, and educational initiatives. Through committee approval processes, investigators at participating sites may additionally access multicenter data for similar initiatives. Emerging from this work are 4 considerations that our group has prioritized to improve data quality: (1) data should be available at the local level before Coordinating Center transfer; (2) data should be rigorously validated against standardized metrics before use; (3) data should be curated into computable phenotypes that are easily accessible; and (4) data should be collected for both research and quality improvement purposes because these complementary goals bolster the strength of each endeavor.

Sugammadex versus Neostigmine for Reversal of Neuromuscular Blockade and Postoperative Pulmonary Complications (STRONGER): A Multicenter Matched Cohort Analysis.

BACKGROUND: Five percent of adult patients undergoing noncardiac inpatient surgery experience a major pulmonary complication. The authors hypothesized that the choice of neuromuscular blockade reversal (neostigmine vs. sugammadex) may be associated with a lower incidence of major pulmonary complications. METHODS: Twelve U.S. Multicenter Perioperative Outcomes Group hospitals were included in a multicenter observational matched-cohort study of surgical cases between January 2014 and August 2018. Adult patients undergoing elective inpatient noncardiac surgical procedures with general anesthesia and endotracheal intubation receiving a nondepolarizing neuromuscular blockade agent and reversal were included. Exact matching criteria included institution, sex, age, comorbidities, obesity, surgical procedure type, and neuromuscular blockade agent (rocuronium vs. vecuronium). Other preoperative and intraoperative factors were compared and adjusted in the case of residual imbalance. The composite primary outcome was major postoperative pulmonary complications, defined as pneumonia, respiratory failure, or other pulmonary complications (including pneumonitis; pulmonary congestion; iatrogenic pulmonary embolism, infarction, or pneumothorax). Secondary outcomes focused on the components of pneumonia and respiratory failure. RESULTS: Of 30,026 patients receiving sugammadex, 22,856 were matched to 22,856 patients receiving neostigmine. Out of 45,712 patients studied, 1,892 (4.1%) were diagnosed with the composite primary outcome (3.5% sugammadex vs. 4.8% neostigmine). A total of 796 (1.7%) patients had pneumonia (1.3% vs. 2.2%), and 582 (1.3%) respiratory failure (0.8% vs. 1.7%). In multivariable analysis, sugammadex administration was associated with a 30% reduced risk of pulmonary complications (adjusted odds ratio, 0.70; 95% CI, 0.63 to 0.77), 47% reduced risk of pneumonia (adjusted odds ratio, 0.53; 95% CI, 0.44 to 0.62), and 55% reduced risk of respiratory failure (adjusted odds ratio, 0.45; 95% CI, 0.37 to 0.56), compared to neostigmine. CONCLUSIONS: Among a generalizable cohort of adult patients undergoing inpatient surgery at U.S. hospitals, the use of sugammadex was associated with a clinically and statistically significant lower incidence of major pulmonary complications.

Intraoperative glycemic control in patients undergoing Orthotopic liver transplant: a single center prospective randomized study.

BACKGROUND: Perioperative hyperglycemia is associated with poor outcomes yet evidence to guide intraoperative goals and treatment modalities during non-cardiac surgery are lacking. End-stage liver disease is associated with altered glucose homeostasis; patients undergoing liver transplantation display huge fluctuations in blood glucose (BG) and represent a population of great interest. Here, we conduct a randomized trial to compare the effects of strict versus conventional glycemic control during orthotopic liver transplant (OLT). METHODS: Following approval by the Institutional Review Board of the University of Michigan Medical School and informed consent, 100 adult patients undergoing OLT were recruited. Patients were randomized to either strict (target BG 80-120 mg/dL) or conventional (target BG 180-200 mg/dL) BG control with block randomization for diabetic and nondiabetic patients. The primary outcomes measured were 1-year patient and graft survival assessed on an intention to treat basis. Graft survival is defined as death or needing re-transplant (www.unos.org). Three and 5-year patient and graft survival, infectious and biliary complications were measured as secondary outcomes. Data were examined using univariate methods and Kaplan-Meir survival analysis. A sensitivity analysis was performed to compare patients with a mean BG of ≤120 mg/dL and those > 120 mg/dL regardless of treatment group. RESULTS: There was no statistically significant difference in patient survival between conventional and strict control respectively;1 year, 88% vs 88% (p-0.99), 3 years, 86% vs 84% (p- 0.77), 5 years, 82% vs 78. % (p-0.36). Graft survival was not different between conventional and strict control groups at 1 year, 88% vs 84% (p-0.56), 3 years 82% vs 76% (p-0.46), 5 years 78% vs 70% (p-0.362). CONCLUSION: There was no difference in patient or graft survival between intraoperative strict and conventional glycemic control during OLT. TRIAL REGISTRATION: Clinical trial number and registry: www.clinicaltrials.gov NCT00780026. This trial was retrospectively registered on 10/22/2008.

Preoperative Risk and the Association between Hypotension and Postoperative Acute Kidney Injury.

BACKGROUND: Despite the significant healthcare impact of acute kidney injury, little is known regarding prevention. Single-center data have implicated hypotension in developing postoperative acute kidney injury. The generalizability of this finding and the interaction between hypotension and baseline patient disease burden remain unknown. The authors sought to determine whether the association between intraoperative hypotension and acute kidney injury varies by preoperative risk. METHODS: Major noncardiac surgical procedures performed on adult patients across eight hospitals between 2008 and 2015 were reviewed. Derivation and validation cohorts were used, and cases were stratified into preoperative risk quartiles based upon comorbidities and surgical procedure. After preoperative risk stratification, associations between intraoperative hypotension and acute kidney injury were analyzed. Hypotension was defined as the lowest mean arterial pressure range achieved for more than 10 min; ranges were defined as absolute (mmHg) or relative (percentage of decrease from baseline). RESULTS: Among 138,021 cases reviewed, 12,431 (9.0%) developed postoperative acute kidney injury. Major risk factors included anemia, estimated glomerular filtration rate, surgery type, American Society of Anesthesiologists Physical Status, and expected anesthesia duration. Using such factors and others for risk stratification, patients with low baseline risk demonstrated no associations between intraoperative hypotension and acute kidney injury. Patients with medium risk demonstrated associations between severe-range intraoperative hypotension (mean arterial pressure less than 50 mmHg) and acute kidney injury (adjusted odds ratio, 2.62; 95% CI, 1.65 to 4.16 in validation cohort). In patients with the highest risk, mild hypotension ranges (mean arterial pressure 55 to 59 mmHg) were associated with acute kidney injury (adjusted odds ratio, 1.34; 95% CI, 1.16 to 1.56). Compared with absolute hypotension, relative hypotension demonstrated weak associations with acute kidney injury not replicable in the validation cohort. CONCLUSIONS: Adult patients undergoing noncardiac surgery demonstrate varying associations with distinct levels of hypotension when stratified by preoperative risk factors. Specific levels of absolute hypotension, but not relative hypotension, are an important independent risk factor for acute kidney injury.

An observational study of end-tidal carbon dioxide trends in general anesthesia.

PURPOSE: Despite growing evidence supporting the potential benefits of higher end-tidal carbon dioxide (ETCO2) levels in surgical patients, there is still insufficient data to formulate guidelines for ideal intraoperative ETCO2 targets. As it is unclear which intraoperative ETCO2 levels are currently used and whether these levels have changed over time, we investigated the practice pattern using the Multicenter Perioperative Outcomes Group database. METHODS: This retrospective, observational, multicentre study included 317,445 adult patients who received general anesthesia for non-cardiothoracic procedures between January 2008 and September 2016. The primary outcome was a time-weighted average area-under-the-curve (TWA-AUC) for four ETCO2 thresholds (< 28, < 35, < 45, and > 45 mmHg). Additionally, a median ETCO2 was studied. A Kruskal-Wallis test was used to analyse differences between years. Random-effect multivariable logistic regression models were constructed to study variability. RESULTS: Both TWA-AUC and median ETCO2 showed a minimal increase in ETCO2 over time, with a median [interquartile range] ETCO2 of 33 [31.0-35.0] mmHg in 2008 and 35 [33.0-38.0] mmHg in 2016 (P <0.001). A large inter-hospital and inter-provider variability in ETCO2 were observed after adjustment for patient characteristics, ventilation parameters, and intraoperative blood pressure (intraclass correlation coefficient 0.36; 95% confidence interval, 0.18 to 0.58). CONCLUSIONS: Between 2008 and 2016, intraoperative ETCO2 values did not change in a clinically important manner. Interestingly, we found a large inter-hospital and inter-provider variability in ETCO2 throughout the study period, possibly indicating a broad range of tolerance for ETCO2, or a lack of evidence to support a specific targeted range. Clinical outcomes were not assessed in this study and they should be the focus of future research.

RéSUMé: OBJECTIF: Malgré une accumulation de données probantes suggérant des avantages de taux plus élevés de dioxyde de carbone en fin d'expiration (ETCO2) chez les patients chirurgicaux, nous ne disposons pas encore d'assez de données pour formuler des lignes directrices sur les cibles peropératoires idéales de l'ETCO2. Comme nous ne savons effectivement pas avec certitude quels taux peropératoires d'ETCO2 sont actuellement utilisés et si ces taux ont changé au fil du temps, nous avons étudié l'évolution de la pratique en utilisant la base de données du MPOG (Multicenter Perioperative Outcomes Group). MéTHODES: Cette étude multicentrique rétrospective observationnelle a inclus 317 445 patients adultes ayant reçu une anesthésie générale pour des procédures non cardiothoraciques entre janvier 2008 et septembre 2016. Le critère d'évaluation principal était une aire sous la courbe moyenne pondérée en fonction du temps (ASC-mT) pour quatre seuils d'ETCO2 (< 28, < 35, < 45 et > 45 mmHg). De plus, une ETCO2 médiane a été étudiée. Un test de Kruskal-Wallis a permis d'analyser les différences entre les années. Des modèles de régression logistique multifactorielle à effet aléatoire ont été construits pour étudier la variabilité. RéSULTATS: L'ASC-mT et l'ETCO2 médiane ont montré une augmentation minime de l'ETCO2 au fil du temps, avec une valeur médiane [plage interquartile] de l'ETCO2 de 33 [31,0 à 35,0] mmHg en 2008 et 35 [33,0 à 38,0] mmHg en 2016 (P < 0,001). Une grande variabilité entre les hôpitaux et prestataires de l'ETCO2 a été observée après ajustement pour les caractéristiques des patients, les paramètres de ventilation et la pression artérielle peropératoire (coefficient de corrélation intracatégorie : 0,36; intervalle de confiance à 95 % : 0,18 à 0,58). CONCLUSIONS: Entre 2008 et 2016, les valeurs peropératoires de l'ETCO2 n'ont pas varié d'une manière importante sur le plan clinique. Il est intéressant de noter que nous avons trouvé une grande variabilité de l'ETCO2 entre hôpitaux et prestataires tout au long de la période d'étude témoignant peut-être d'une vaste plage de tolérance de l'ETCO2 ou d'un manque de données probantes pour soutenir une valeur cible spécifique. L'évolution clinique n'a pas été analysée au cours de cette étude et elle devra être le centre d'intérêt de futures recherches.

Airway Management and Clinical Outcomes in External Laryngeal Trauma: A Case Series.

External laryngeal trauma is a rare but potentially fatal event that presents several management challenges. This retrospective observational case series conducted at a level-1 trauma center over a 12-year period consists of 62 cases of acute external laryngeal trauma. Patient demographics, mode and mechanisms of injury, presenting signs and symptoms, initial imaging results, airway management, time to surgical management, and 6-month outcomes including airway status, deglutition status, and voice quality were investigated. No difference was found in mortality or 6-month outcomes between patients requiring surgical repair and/or tracheostomy versus patients with less severe injuries managed conservatively.

Intraoperative hyperglycemia is independently associated with infectious complications after non-cardiac surgery.

BACKGROUND: Perioperative hyperglycemia and its associated increase in morbidity and mortality have been well studied in the critical care and cardiac surgery literature. However, there is little data regarding the impact of intraoperative hyperglycemia on post-operative infectious complications in non-cardiac surgery. METHODS: All National Surgery Quality Improvement Program patients undergoing general, vascular, and urological surgery at our tertiary care center were reviewed. After integrating intraoperative glucose measurements from our intraoperative electronic health record, we categorized patients as experiencing mild (8.3-11.0 mmol/L), moderate (11.1-16.6 mmol/L), and severe (≥ 16.7 mmol/L) intraoperative hyperglycemia. Using multiple logistic regression to adjust for patient comorbidities and surgical factors, we evaluated the association of hyperglycemia with the primary outcome of postoperative surgical site infection, pneumonia, urinary tract infection, or sepsis within 30 days. RESULTS: Of 13,954 patients reviewed, 3150 patients met inclusion criteria and had an intraoperative glucose measurement. 49% (n = 1531) of patients experienced hyperglycemia and 15% (n = 482) patients experienced an infectious complication. Patients with mild (adjusted odds ratio 1.30, 95% confidence interval [1.01 to 1.68], p-value = 0.04) and moderate hyperglycemia (adjusted odds ratio 1.57, 95% confidence interval [1.08-2.28], p-value = 0.02) had a statistically significant risk-adjusted increase in infectious complications. The model c-statistic was 0.72 [95% confidence interval 0.69-0.74]. CONCLUSIONS: This is one of the first studies to demonstrate an independent relationship between intraoperative hyperglycemia and postoperative infectious complications. Future studies are needed to evaluate a causal relationship and impact of treatment.

Impact of a Novel Multiparameter Decision Support System on Intraoperative Processes of Care and Postoperative Outcomes.

BACKGROUND: The authors hypothesized that a multiparameter intraoperative decision support system with real-time visualizations may improve processes of care and outcomes. METHODS: Electronic health record data were retrospectively compared over a 6-yr period across three groups: experimental cases, in which the decision support system was used for 75% or more of the case at sole discretion of the providers; parallel controls (system used 74% or less); and historical controls before system implementation. Inclusion criteria were adults under general anesthesia, advanced medical disease, case duration of 60 min or longer, and length of stay of two days or more. The process measures were avoidance of intraoperative hypotension, ventilator tidal volume greater than 10 ml/kg, and crystalloid administration (ml · kg · h). The secondary outcome measures were myocardial injury, acute kidney injury, mortality, length of hospital stay, and encounter charges. RESULTS: A total of 26,769 patients were evaluated: 7,954 experimental cases, 10,933 parallel controls, and 7,882 historical controls. Comparing experimental cases to parallel controls with propensity score adjustment, the data demonstrated the following medians, interquartile ranges, and effect sizes: hypotension 1 (0 to 5) versus 1 (0 to 5) min, P < 0.001, beta = -0.19; crystalloid administration 5.88 ml · kg · h (4.18 to 8.18) versus 6.17 (4.32 to 8.79), P < 0.001, beta = -0.03; tidal volume greater than 10 ml/kg 28% versus 37%, P < 0.001, adjusted odds ratio 0.65 (0.53 to 0.80); encounter charges $65,770 ($41,237 to $123,869) versus $69,373 ($42,101 to $132,817), P < 0.001, beta = -0.003. The secondary clinical outcome measures were not significantly affected. CONCLUSIONS: The use of an intraoperative decision support system was associated with improved process measures, but not postoperative clinical outcomes.

Propofol Drug Shortage Associated With Worse Postoperative Nausea and Vomiting Outcomes Despite a Mitigation Strategy.

Drug shortages negatively affect patient care and outcomes. Postoperative nausea and vomiting (PONV) can be mitigated using risk assessment and prophylaxis. A 2012 propofol shortage provided an opportunity to study the impact of using prophylactic antiemetics and changing the technique from a propofol infusion to inhaled agents in an ambulatory surgery setting. We retrospectively collected data for 2,090 patients regarding PONV risk factors, anesthetic management, and PONV outcomes for periods before, during, and after the shortage. Patients during the propofol shortage experienced a higher incidence of PONV (11% vs 5% before the shortage), greater need for rescue antiemetics (3% vs 1%), and longer duration of stay (mean [SD] = 124 [115] minutes vs 118 [108] minutes). More patients in this group reported PONV at home (14% vs 7%), and 2 required unplanned admission or return to the hospital. During the shortage, patients had a 2-fold increase in the odds of PONV when adjusted for all risk factors. Antiemetics moderated the association between gender and PONV but did not change the effect of the shortage. Findings suggest that despite mitigation efforts, the inability to use propofol infusion was associated with worse PONV outcomes.

Influence of non-invasive blood pressure measurement intervals on the occurrence of intra-operative hypotension.

The American Society of Anesthesiologists Standards for Basic Monitoring recommends blood pressure (BP) measurement every 5 min. Research has shown distractions or technical factors can cause prolonged measurement intervals exceeding 5 min. We investigated the relationship between prolonged non-invasive BP (NIBP) measurement interval and the incidence of hypotension, detected post-interval. Our secondary outcome was to determine independent predictors of these prolonged NIBP measurement intervals. Retrospective data were analyzed from 139,509 general anesthesia cases from our institution's Anesthesia Information Management System (AIMS). Absolute hypotension (AH) was defined a priori as a systolic BP < 80 mmHg and relative hypotension (RH) was defined as a 40% decrease in systolic BP from the preoperative baseline. Odds ratios (OR) with 95% confidence intervals and Pearson's Chi square Test reported the association of prolonged NIBP measurement intervals on hypotension detected post-NIBP measurement interval. Logistic regression models were developed to determine independent predictors of NIBP measurement intervals. The analysis revealed that NIBP measurement intervals greater than 6 and 10 min are associated with an approximately four times higher incidence of a patient transitioning into hypotension (AH/RH > 6 min OR 4.0 / 3.6; AH/RH > 10 min OR 4.3 / 3.9; p < 0.001). A key finding was that the "> 10-minute AH model" indicated that age 41-80, increased co-morbidity profile, obesity and turning (repositioning) of the operative room table were significant predictors of prolonged NIBP measurement intervals (p < 0.001). While we do not suggest NIBP measurement intervals cause hypotension, intervals greater than 6 and 10 min are associated with a fourfold increase in the propensity of an undetected transition into both RH or AH. These data support current monitoring guidelines.

Management of 1-Lung Ventilation-Variation and Trends in Clinical Practice: A Report From the Multicenter Perioperative Outcomes Group.

BACKGROUND: Lung-protective ventilation (LPV) has been demonstrated to improve clinical outcomes in surgical patients. There are very limited data on the current use of LPV for patients undergoing 1-lung ventilation (1LV) despite evidence that 1LV may be a particularly important setting for its use. In this multicenter study, we report trends in ventilation practice for patients undergoing 1LV. METHODS: The Multicenter Perioperative Outcomes Group database was used to identify patients undergoing 1LV. We retrieved and calculated median initial and overall tidal volume (VT) for the cohort and for high-risk subgroups (female sex, obesity [body mass index >30 kg/m], and short stature), percentage of patients receiving positive end-expiratory pressure (PEEP) ≥5 cm H2O, LPV during 1LV (VT ≤ 6 mL/kg predicted body weight [PBW] and PEEP ≥5 cm H2O), and ventilator driving pressure (ΔP; plateau airway pressure - PEEP). RESULTS: Data from 5609 patients across 4 institutions were included in the analysis. Median VT was calculated for each case and since the data were normally distributed, the mean is reported for the entire cohort and subgroups. Mean of median VT during 1LV for the cohort was 6.49 ± 1.82 mL/kg PBW. VT (mL/kg PBW) for high-risk subgroups was significantly higher; 6.86 ± 1.97 for body mass index ≥30 kg/m, 7.05 ± 1.92 for female patients, and 7.33 ± 2.01 for short stature patients. Mean of the median VT declined significantly over the study period (from 6.88 to 5.72; P < .001), and the proportion of patients receiving LPV increased significantly over the study period (from 9.1% to 54.6%; P < .001). These changes coincided with a significant decrease in ΔP during the study period, from 19.4 cm H2O during period 1 to 17.3 cm H2O in period 12 (P = .003). CONCLUSIONS: Despite a growing awareness of the importance of protective ventilation, a large proportion of patients undergoing 1LV continue to receive VT PEEP levels outside of recommended thresholds. Moreover, VT remains higher and LPV less common in high-risk subgroups, potentially placing them at elevated risk for iatrogenic lung injury.

Postoperative Respiratory Complications in Patients at Risk for Obstructive Sleep Apnea: A Single-Institution Cohort Study.

BACKGROUND: Obstructive sleep apnea (OSA) is a prevalent condition that is associated with early postoperative respiratory complications (PRCs). As the majority of patients with OSA are undiagnosed, preoperative screening remains the most efficient method to identify suspected OSA. METHODS: This retrospective study was performed on patients undergoing anesthesia in a single academic medical center. We assigned OSA risk class retrospectively to all patients in the study by using the Perioperative Sleep Apnea Prediction (PSAP) score. We evaluated the relationship between PSAP categories and early postoperative invasive airway placement after adjusting for several preoperative and intraoperative factors (including surgical risk) previously associated with PRC occurrence. RESULTS: A total of 108,479 patients were included in the final analysis with an incidence of PRC was 0.3% (n = 280). High PSAP score was associated with postoperative intubation (adjusted odds ratio, 2.3; 95% confidence interval, 1.5-3.7). Several risk factors reflecting anesthetic agents, neuromuscular blocking agents, and opioids were also independently associated with early PRC. CONCLUSIONS: We report that suspected OSA based on the PSAP score is independently associated with increased risk of early PRC. Specific anesthetic agents are independently associated with early PRC, pointing to the potential for examining risk modification through these exposures in future studies.

Retrospective observational evaluation of postoperative oxygen saturation levels and associated postoperative respiratory complications and hospital resource utilization.

INTRODUCTION: The clinical importance of postoperative episodic hypoxemia is still unclear, and therefore largely under-studied. As a result, there is limited understanding of its relationship with early postoperative respiratory complications (PRC, defined as intubation within three days of surgery) and hospital resource utilization. MATERIALS AND METHODS: This single center study was performed using a retrospective observational design. We described population based definitions of desaturation from continuous SpO2 monitoring data captured in the post anesthesia care unit (PACU), namely median SpO2 in PACU, duration of desaturation below median, nadir desaturation, and length of oxygen therapy relative to PACU duration. These measures were evaluated against the occurrence of early PRC in logistic regression models. Measures that were independently associated with early PRC were accepted as the primary study exposures. Stratified logistic regression models were planned if significant interaction occurred with high risk surgical procedures. Models were adjusted by including several patient conditions, procedural, and anesthesia risk factors. Propensity matching on desaturation occurrence was planned to evaluate the relationship with postoperative resource utilization. RESULTS: Among 125,740 patients included in the univariate analyses, 351 patients (0.3%) developed early PRC. Nadir desaturation <89% [14.3% of patients; adjusted odds ratio 2.02; 95% CI 1.52, 2.68; p<0.001] and PACU oxygen therapy requirements greater than 60 min [adjusted odds ratio 1.92 (>60 min) to 3.04 (>90 min); p<0.001] were identified as independent predictors of early PRC occurrence. A modest interaction was observed between desaturation and higher surgical risk. Propensity matching for postoperative oxygen requirement was performed in 37,354 matched patients. Matched analysis demonstrated significant increase in day of surgery charges, respiratory charges, total charges, hospital length of stay, reintubation and use of invasive or non-invasive ventilatory support. CONCLUSIONS: In summary, we report that prolonged PACU oxygen therapy and nadir desaturation <89% in PACU as captured in a retrospective database are independently associated with early PRC. This study describes resource implications of PACU desaturation in a large academic medical center in North America.

Preoperative ß-blockade and hypertension in the first hour of functional endoscopic sinus surgery.

OBJECTIVES/HYPOTHESIS: Local anesthetic with epinephrine is commonly injected into the nasal mucosa during functional endoscopic sinus surgery (FESS). Systemic absorption of epinephrine following local injection may occur, resulting in a mild sympathetic response. This study seeks to determine whether an exaggerated sympathetic response to epinephrine is demonstrated in patients undergoing FESS treated preoperatively with established pharmacologic beta (ß) adrenoceptor blockade. STUDY DESIGN: A retrospective analysis of adult patients undergoing FESS at a tertiary care university hospital. METHODS: The primary outcome was the occurrence of an exaggerated hypertensive response within the first hour of surgical time defined by a relative increase (>20%) in the first measured intraoperative systolic blood pressure (SBP) prior to induction of anesthesia, or a single SBP value above 200 mm Hg. A mixed effects logistic regression model was developed to identify independent predictors of an exaggerated hypertensive response and describe the variance in the outcome attributable to the surgeon and anesthesiologist. RESULTS: There were 2,051 patients identified. Independent predictors of an exaggerated intraoperative hypertensive event included: preoperative ß-blocker use (adjusted odds ratio [AOR]: 3.33), female gender (AOR: 1.92), body mass index (AOR: 1.03), lower baseline SBP (AOR: 0.93), and advanced age (AOR: 1.03). The C statistic for the model was 0.8881. CONCLUSIONS: Preoperative ß-blocker use is an independent predictor of an exaggerated hypertensive response within the first hour of operative time. An exaggerated hypertensive effect should be anticipated in patients presenting for FESS with established pharmacologic ß-blockade, and caution should be applied to use of epinephrine-containing solutions. LEVEL OF EVIDENCE: 4. Laryngoscope, 127:1496-1505, 2017.

Frequency of inadequate neuromuscular blockade during general anesthesia.

STUDY OBJECTIVE: We used electronic health record data to define frequency of inadequate intraoperative neuromuscular blockade (NMB). DESIGN: Retrospective observational study using electronic health record data. SETTING: Operating room in a tertiary care academic hospital. PATIENTS: A total of 129,209 adult patients with American Society of Anesthesiologists physical status 1 to 5 undergoing general anesthesia in an outpatient or inpatient setting who received nondepolarizing NMB. We excluded patients intubated before arrival to the operating room, patients undergoing a liver transplant or cardiac surgery, and patients who remained intubated at the end of the operation. INTERVENTIONS: None. MEASUREMENTS: The primary outcomes were inadequate NMB defined by (1) documentation of patient movement and (2) documentation of surgical request for additional NMB, followed by NMB agent administration. MAIN RESULTS: A total of 1261 patients (1.0%) demonstrated either intraoperative movement (369 or 0.29%) or prompted surgical request for additional NMB agent (921 or 0.71%). Trend analysis showed a variation in the annual rate of inadequate NMB, with an increase from 2004 to 2013 for criteria 1 and 2. CONCLUSIONS: Nearly 1% of all general anesthetic procedures involving NMB exhibit inadequate relaxation resulting in procedural interruption. These data suggest that current use of neuromuscular blocking drugs and NMB monitoring expose patients to inadequate blockade. The risk of this phenomenon warrants further study.

Arterial Pressure Variation in Elective Noncardiac Surgery: Identifying Reference Distributions and Modifying Factors.

BACKGROUND: Assessment of need for intravascular volume resuscitation remains challenging for anesthesiologists. Dynamic waveform indices, including systolic and pulse pressure variation, are demonstrated as reliable measures of fluid responsiveness for mechanically ventilated patients. Despite widespread use, real-world reference distributions for systolic and pulse pressure variation values have not been established for euvolemic intraoperative patients. The authors sought to establish systolic and pulse pressure variation reference distributions and assess the impact of modifying factors. METHODS: The authors evaluated adult patients undergoing general anesthetics for elective noncardiac surgery. Median systolic and pulse pressure variations during a 50-min postinduction period were noted for each case. Modifying factors including body mass index, age, ventilator settings, positioning, and hemodynamic management were studied via univariate and multivariable analyses. For systolic pressure variation values, effects of data entry method (manually entered vs. automated recorded) were similarly studied. RESULTS: Among 1,791 cases, per-case median systolic and pulse pressure variation values formed nonparametric distributions. For each distribution, median values, interquartile ranges, and reference intervals (2.5th to 97.5th percentile) were, respectively, noted: these included manually entered systolic pressure variation (6.0, 5.0 to 7.0, and 3.0 to 11.0 mmHg), automated systolic pressure variation (4.7, 3.9 to 6.0, and 2.2 to 10.4 mmHg), and automated pulse pressure variation (7.0, 5.0 to 9.0, and 2.0 to 16.0%). Nonsupine positioning and preoperative ß blocker were independently associated with altered systolic and pulse pressure variations, whereas ventilator tidal volume more than 8 ml/kg ideal body weight and peak inspiratory pressure more than 16 cm H2O demonstrated independent associations for systolic pressure variation only. CONCLUSIONS: This study establishes real-world systolic and pulse pressure variation reference distributions absent in the current literature. Through a consideration of reference distributions and modifying factors, the authors' study provides further evidence for assessing intraoperative volume status and fluid management therapies.

Success of Intubation Rescue Techniques after Failed Direct Laryngoscopy in Adults: A Retrospective Comparative Analysis from the Multicenter Perioperative Outcomes Group.

BACKGROUND: Multiple attempts at tracheal intubation are associated with mortality, and successful rescue requires a structured plan. However, there remains a paucity of data to guide the choice of intubation rescue technique after failed initial direct laryngoscopy. The authors studied a large perioperative database to determine success rates for commonly used intubation rescue techniques. METHODS: Using a retrospective, observational, comparative design, the authors analyzed records from seven academic centers within the Multicenter Perioperative Outcomes Group between 2004 and 2013. The primary outcome was the comparative success rate for five commonly used techniques to achieve successful tracheal intubation after failed direct laryngoscopy: (1) video laryngoscopy, (2) flexible fiberoptic intubation, (3) supraglottic airway as part of an exchange technique, (4) optical stylet, and (5) lighted stylet. RESULTS: A total of 346,861 cases were identified that involved attempted tracheal intubation. A total of 1,009 anesthesia providers managed 1,427 cases of failed direct laryngoscopy followed by subsequent intubation attempts (n = 1,619) that employed one of the five studied intubation rescue techniques. The use of video laryngoscopy resulted in a significantly higher success rate (92%; 95% CI, 90 to 93) than other techniques: supraglottic airway conduit (78%; 95% CI, 68 to 86), flexible bronchoscopic intubation (78%; 95% CI, 71 to 83), lighted stylet (77%; 95% CI, 69 to 83), and optical stylet (67%; 95% CI, 35 to 88). Providers most frequently choose video laryngoscopy (predominantly GlideScope [Verathon, USA]) to rescue failed direct laryngoscopy (1,122/1,619; 69%), and its use has increased during the study period. CONCLUSIONS: Video laryngoscopy is associated with a high rescue intubation success rate and is more commonly used than other rescue techniques.

Recognition and Management of Perioperative Stroke in Hospitalized Patients.

We sought to characterize stroke management and outcomes in a postoperative population. By using the electronic medical records, we identified 39 patients suffering perioperative stroke after noncardiac and nonneurosurgical procedures for whom documentation of management and outcomes was available. Thirty-three strokes occurred during admission, whereas 6 occurred after discharge and were recognized upon return to the hospital. Perioperative stroke was associated with delayed recognition, infrequent intervention, and significant rates of morbidity and mortality, suggesting the need for improved screening and more rapid treatment. There may be disparities in care and outcomes between in-hospital and out-of hospital stroke patients, though further study is warranted.

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.