Perioperative Mortality of the COVID-19 Recovered Patient Compared to a Matched Control: A Multicenter Retrospective Cohort Study.

BACKGROUND: Surgical procedures performed on patients with recent exposure to COVID-19 infection have been associated with increased mortality risk in previous studies. Accordingly, elective surgery is often delayed after infection. The study aimed to compare 30-day hospital mortality and postoperative complications (acute kidney injury, pulmonary complications) of surgical patients with a previous COVID-19 infection to a matched cohort of patients without known previous COVID-19. The authors hypothesized that COVID-19 exposure would be associated with an increased mortality risk. METHODS: In this retrospective observational cohort study, patients presenting for elective inpatient surgery across a multicenter cohort of academic and community hospitals from April 2020 to April 2021 who had previously tested positive for COVID-19 were compared to controls who had received at least one previous COVID-19 test but without a known previous COVID-19-positive test. The cases were matched based on anthropometric data, institution, and comorbidities. Further, the outcomes were analyzed stratified by timing of a positive test result in relation to surgery. RESULTS: Thirty-day mortality occurred in 229 of 4,951 (4.6%) COVID-19-exposed patients and 122 of 4,951 (2.5%) controls. Acute kidney injury was observed in 172 of 1,814 (9.5%) exposed patients and 156 of 1,814 (8.6%) controls. Pulmonary complications were observed in 237 of 1,637 (14%) exposed patients and 164 of 1,637 (10%) controls. COVID-19 exposure was associated with an increased 30-day mortality risk (adjusted odds ratio, 1.63; 95% CI, 1.38 to 1.91) and an increased risk of pulmonary complications (1.60; 1.36 to 1.88), but was not associated with an increased risk of acute kidney injury (1.03; 0.87 to 1.22). Surgery within 2 weeks of infection was associated with a significantly increased risk of mortality and pulmonary complications, but that effect was nonsignificant after 2 weeks. CONCLUSIONS: Patients with a positive test for COVID-19 before elective surgery early in the pandemic have an elevated risk of perioperative mortality and pulmonary complications but not acute kidney injury as compared to matched controls. The span of time from positive test to time of surgery affected the mortality and pulmonary risk, which subsided after 2 weeks.

Postconceptual Neonatal Dating by Transmastoid Ultrasound of Transcerebellar Diameter-Comparison to Crown Rump Length Measurement: A Proof of Concept Paper.

OBJECTIVES: Transcerebellar diameter (TCD) has been utilized prenatally as a tool to estimate gestational age (GA) when fetal growth aberrations are suspected. Traditionally, first trimester ultrasound (1TUS) has been the gold standard of dating a pregnancy in spontaneous pregnancies. We sought to determine if neonatal TCD measurement was as accurate as 1TUS in the estimation of postconceptual gestational age (PCGA). METHODS: A retrospective cohort from a registry of high-quality transmastoid views of consecutive patients from July 2019 to November 2020, delivered from 24 to 34 weeks GA, and with a 1TUS were included. The reference PCGA was the sum of the GA at delivery by 1TUS and day of life. The PCGA by TCD was calculated from Chang et al for GA by TCD. Reference and experimental values were compared by correlation, agreement within 7 days, and Bland-Altman analysis. RESULTS: Of the 154 individual patients in the registry of high-quality transmastoid views during the study period, 62 met inclusion and exclusion criteria. PCGA by 1TUS and TCD were highly correlated (r = 0.86, P < .001; κ = 47% agreement within 7 days of PCGA). The bias of PCGA by TCD was 4.6 days earlier than the PCGA by 1TUS (95% confidence interval of agreement: -29.2, 20). CONCLUSIONS: PCGA estimation by neonatal transmastoid TCD was highly correlated with that of 1TUS. It generally underestimates GA by 4.6 days. This relationship warrants further investigation to determine if this method of estimating PCGA in undated gestations is generalizable.

Membrane-Electrolyte System Approach to Understanding Ionic Conductivity and Crossover in Alkaline Flow Cells.

Membrane transport properties are crucial for electrochemical devices, and these properties are influenced by the composition and concentration of the electrolyte in contact with the membrane. We apply this general membrane-electrolyte system approach to alkaline flow batteries, studying the conductivity and ferricyanide crossover of Nafion and E-620. We report undetectable crossover for as-received Nafion and E-620 after both sodium and potassium exchange but high ferricyanide permeability of 10-7 to 10-8 cm2 s-1 for Nafion subjected to pretreatment prevalent in the flow battery literature. We show how the electrolyte mass fraction in hydrated membranes regulates the influence of ion concentration on membrane conductivity, identifying that increasing electrolyte concentration may not increase membrane conductivity even when it increases electrolyte conductivity. To illustrate this behavior, we introduce a new metric, the membrane penalty, as the ratio of the conductivity of the electrolyte to that of the membrane equilibrated with the electrolyte. We discuss the trade-off between flow battery volumetric capacity and areal power density that arises from these findings. Finally, we apply insights from this approach to provide recommendations for use of membranes in alkaline flow cells and electrochemical reactors in general.

Reversible CO2 Capture and On-Demand Release by an Acidity-Matched Organic Photoswitch.

Separation of carbon dioxide (CO2) from point sources or directly from the atmosphere can contribute crucially to climate change mitigation plans in the coming decades. A fundamental practical limitation for the current strategies is the considerable energy cost required to regenerate the sorbent and release the captured CO2 for storage or utilization. A directly photochemically driven system that demonstrates efficient passive capture and on-demand CO2 release triggered by sunlight as the sole external stimulus would provide an attractive alternative. However, little is known about the thermodynamic requirements for such a process or mechanisms for modulating the stability of CO2-derived dissolved species by using photoinduced metastable states. Here, we show that an organic photoswitchable molecule of precisely tuned effective acidity can repeatedly capture and release a near-stoichiometric quantity of CO2 according to dark-light cycles. The CO2-derived species rests as a solvent-separated ion pair, and key aspects of its excited-state dynamics that regulate the photorelease efficiency are characterized by transient absorption spectroscopy. The thermodynamic and kinetic concepts established herein will serve as guiding principles for the development of viable solar-powered negative emission technologies.

Adverse maternal outcomes associated with major fetal malformations after singleton live birth.

BACKGROUND: Major fetal malformations complicate 2% to 5% of live births. It is unclear what effect fetal malformations have on severe maternal morbidity. OBJECTIVE: This study aimed to compare maternal outcomes between individuals with a fetus with major or minor fetal malformations and those with a fetus without major or minor fetal malformations. STUDY DESIGN: This was a secondary analysis of the Consortium on Safe Labor database. Our study was limited to the current analysis of pregnant individuals with a singleton live birth. Major fetal malformations based on the Centers for Disease Control and Prevention's criteria were defined. Fetal malformations that did not meet the criteria for major fetal malformations were categorized as minor fetal malformations. Our primary maternal outcome was severe maternal morbidity as defined by the Centers for Disease Control and Prevention. Missing values were imputed by multiple imputation using the k-nearest neighbor imputation method. Poisson regression with robust error variance was used to obtain adjusted relative risks with 95% confidence intervals, controlling for confounders. RESULTS: Of 216,881 deliveries, there were 201,860 cases (93.1%) with no congenital malformation, 12,106 cases (5.6%) with minor fetal malformations, and 2845 cases (1.3%) with major fetal malformations. Compared with individuals with no fetal malformation, those with major fetal malformations were more likely to have severe maternal morbidity (0.7% vs 1.2%; adjusted relative risk, 1.51; 95% confidence interval, 1.07-2.12), postpartum hemorrhage (3.6% vs 6.9%; adjusted relative risk, 1.76; 95% confidence interval, 1.50-2.06), preeclampsia (5.1% vs 8.3%; adjusted relative risk, 1.48; 95% confidence interval, 1.31-1.67), and cesarean delivery (26.7% vs 42.3%; adjusted relative risk, 1.51; 95% confidence interval, 1.45-1.58). Compared with individuals with no fetal malformation, those with minor fetal malformations were more likely to have severe maternal morbidity (0.7% vs 1.4%; adjusted relative risk, 1.73; 95% confidence interval, 1.48-2.02), maternal death (0.01% vs 0.03%; adjusted relative risk, 4.50; 95% confidence interval, 1.18-17.19), postpartum hemorrhage (3.6% vs 6.1%; adjusted relative risk, 1.54; 95% confidence interval, 1.41-1.68), preeclampsia (5.1% vs 8.6%; adjusted relative risk, 1.50; 95% confidence interval, 1.41-1.60), superimposed preeclampsia (1.2% vs 2.4%; adjusted relative risk, 1.25; 95% confidence interval, 1.14-1.38), cesarean delivery (26.7% vs 39.6%; adjusted relative risk, 1.38; 95% confidence interval, 1.35-1.41), chorioamnionitis (3.0% vs 4.7%; adjusted relative risk, 1.41; 95% confidence interval, 1.29-1.53), and postpartum endometritis (0.6% vs 1.0%; adjusted relative risk, 1.58; 95% confidence interval, 1.31-1.90). CONCLUSION: Major and minor congenital fetal malformations are independent risk factors for severe maternal morbidity and other pregnancy complications.

Pro-Con Debate: Videolaryngoscopy Should Be Standard of Care for Tracheal Intubation.

In this Pro-Con commentary article, we discuss whether videolaryngoscopy (VL) should be the standard of care for tracheal intubation. Dr Aziz makes the case that VL should be the standard of care, while Dr Berkow follows with a challenge of that assertion. In this debate, we explore not only the various benefits of VL, but also its limitations. There is compelling evidence that VL improves first-pass success rates, reduces the risk of intubation failure and esophageal intubation, and has benefits in the difficult airway patient. But VL is not without complications and does not possess a 100% success rate. In the case of failure, it is important to have back-up plans for airway management. While transition of care from direct laryngoscopy (DL) to VL may result in improved airway management outcomes, the reliance on VL may degrade other important clinical skills when they are needed most. If VL is adapted as the standard of care, airway managers may no longer practice and retain competency in other airway techniques that may be required in the event of VL failure. While cost is a barrier to broad implementation of VL, those costs are normalizing. However, it may still be challenging for institutions to secure purchase of VL for every intubating location, as well as back-up airway devices. As airway management care increasingly transitions from DL to VL, providers should be aware of the benefits and risks to this practice change.

Prolonged Opioid Use and Pain Outcome and Associated Factors after Surgery under General Anesthesia: A Prospective Cohort Association Multicenter Study.

BACKGROUND: There is insufficient prospective evidence regarding the relationship between surgical experience and prolonged opioid use and pain. The authors investigated the association of patient characteristics, surgical procedure, and perioperative anesthetic course with postoperative opioid consumption and pain 3 months postsurgery. The authors hypothesized that patient characteristics and intraoperative factors predict opioid consumption and pain 3 months postsurgery. METHODS: Eleven U.S. and one European institution enrolled patients scheduled for spine, open thoracic, knee, hip, or abdominal surgery, or mastectomy, in this multicenter, prospective observational study. Preoperative and postoperative data were collected using patient surveys and electronic medical records. Intraoperative data were collected from the Multicenter Perioperative Outcomes Group database. The association between postoperative opioid consumption and surgical site pain at 3 months, elicited from a telephone survey conducted at 3 months postoperatively, and demographics, psychosocial scores, pain scores, pain management, and case characteristics, was analyzed. RESULTS: Between September and October 2017, 3,505 surgical procedures met inclusion criteria. A total of 1,093 cases were included; 413 patients were lost to follow-up, leaving 680 (64%) for outcome analysis. Preoperatively, 135 (20%) patients were taking opioids. Three months postsurgery, 96 (14%) patients were taking opioids, including 23 patients (4%) who had not taken opioids preoperatively. A total of 177 patients (27%) reported surgical site pain, including 45 (13%) patients who had not reported pain preoperatively. The adjusted odds ratio for 3-month opioid use was 18.6 (credible interval, 10.3 to 34.5) for patients who had taken opioids preoperatively. The adjusted odds ratio for 3-month surgical site pain was 2.58 (1.45 to 4.4), 4.1 (1.73 to 8.9), and 2.75 (1.39 to 5.0) for patients who had site pain preoperatively, knee replacement, or spine surgery, respectively. CONCLUSIONS: Preoperative opioid use was the strongest predictor of opioid use 3 months postsurgery. None of the other variables showed clinically significant association with opioid use at 3 months after surgery.

Has the time really come for universal videolaryngoscopy?

Recent evidence, highlighted in this editorial, creates a strong argument for universal use of videolaryngoscopy in anaesthesia to improve efficiency and safety of tracheal intubation. In a recent study published in the British Journal of Anaesthesia, the authors implemented widespread (66%) use of videolaryngoscopy as first choice in one hospital and compared this with a control hospital, in which this was not implemented. Increased videolaryngoscopy use was associated with a significant fall in the rate of difficult airways, use of airway rescue techniques, and operator-reported difficulty, whilst in the control hospitals no such changes were seen. Locations outside the operating theatre might also benefit from universal laryngoscopy, but the evidence base is less robust, most notably in pre-hospital emergency medicine. The extent to which variation in results in different locations is attributable to different patient factors or organisational and operator factors is considered.

Unrecognised oesophageal intubation: time for action.

Patients worldwide die every year from unrecognised oesophageal intubation, which is an avoidable complication of airway management usually resulting from human error. Unrecognised oesophageal intubation can occur in any patient of any age whenever intubation occurs regardless of the seniority or experience of the airway practitioner or others involved in the patient's airway management. The tragic fact is that it continues to happen despite improvements in monitoring, airway devices, and medical education. We review these improvements with strategies to eliminate this problem.

Carbon Dioxide, Blood Pressure, and Perioperative Stroke: A Retrospective Case-Control Study.

BACKGROUND: The relationship between intraoperative physiology and postoperative stroke is incompletely understood. Preliminary data suggest that either hypo- or hypercapnia coupled with reduced cerebrovascular inflow (e.g., due to hypotension) can lead to ischemia. This study tested the hypothesis that the combination of intraoperative hypotension and either hypo- or hypercarbia is associated with postoperative ischemic stroke. METHODS: We conducted a retrospective, case-control study via the Multicenter Perioperative Outcomes Group. Noncardiac, nonintracranial, and nonmajor vascular surgical cases (18 yr or older) were extracted from five major academic centers between January 2004 and December 2015. Ischemic stroke cases were identified via manual chart review and matched to controls (1:4). Time and reduction below key mean arterial blood pressure thresholds (less than 55 mmHg, less than 60 mmHg, less than 65 mmHg) and outside of specific end-tidal carbon dioxide thresholds (30 mmHg or less, 35 mmHg or less, 45 mmHg or greater) were calculated based on total area under the curve. The association between stroke and total area under the curve values was then tested while adjusting for relevant confounders. RESULTS: In total, 1,244,881 cases were analyzed. Among the cases that screened positive for stroke (n = 1,702), 126 were confirmed and successfully matched with 500 corresponding controls. Total area under the curve was significantly associated with stroke for all thresholds tested, with the strongest combination observed with mean arterial pressure less than 55 mmHg (adjusted odds ratio per 10 mmHg-min, 1.17 [95% CI, 1.10 to 1.23], P < 0.0001) and end-tidal carbon dioxide 45 mmHg or greater (adjusted odds ratio per 10 mmHg-min, 1.11 [95% CI, 1.10 to 1.11], P < 0.0001). There was no interaction effect observed between blood pressure and carbon dioxide. CONCLUSIONS: Intraoperative hypotension and carbon dioxide dysregulation may each independently increase postoperative stroke risk.

In situ electrochemical recomposition of decomposed redox-active species in aqueous organic flow batteries.

Aqueous organic redox flow batteries offer a safe and potentially inexpensive solution to the problem of storing massive amounts of electricity produced from intermittent renewables. However, molecular decomposition represents a major barrier to commercialization-and although structural modifications can improve stability, it comes at the expense of synthetic cost and molecular weight. Now, utilizing 2,6-dihydroxy-anthraquinone (DHAQ) without further structural modification, we demonstrate that the regeneration of the original molecule after decomposition represents a viable route to achieve low-cost, long-lifetime aqueous organic redox flow batteries. We used in situ (online) NMR and electron paramagnetic resonance, and complementary electrochemical analyses to show that the decomposition compound 2,6-dihydroxy-anthrone (DHA) and its tautomer, 2,6-dihydroxy-anthranol (DHAL) can be recomposed to DHAQ electrochemically through two steps: oxidation of DHA(L)2- to the dimer (DHA)24- by one-electron transfer followed by oxidation of (DHA)24- to DHAQ2- by three-electron transfer per DHAQ molecule. This electrochemical regeneration process also rejuvenates the positive electrolyte-rebalancing the states of charge of both electrolytes without introducing extra ions.

Low energy carbon capture via electrochemically induced pH swing with electrochemical rebalancing.

We demonstrate a carbon capture system based on pH swing cycles driven through proton-coupled electron transfer of sodium (3,3'-(phenazine-2,3-diylbis(oxy))bis(propane-1-sulfonate)) (DSPZ) molecules. Electrochemical reduction of DSPZ causes an increase of hydroxide concentration, which absorbs CO2; subsequent electrochemical oxidation of the reduced DSPZ consumes the hydroxide, causing CO2 outgassing. The measured electrical work of separating CO2 from a binary mixture with N2, at CO2 inlet partial pressures ranging from 0.1 to 0.5 bar, and releasing to a pure CO2 exit stream at 1.0 bar, was measured for electrical current densities of 20-150 mA cm-2. The work for separating CO2 from a 0.1 bar inlet and concentrating into a 1 bar exit is 61.3 kJ molCO2-1 at a current density of 20 mA cm-2. Depending on the initial composition of the electrolyte, the molar cycle work for capture from 0.4 mbar extrapolates to 121-237 kJ molCO2-1 at 20 mA cm-2. We also introduce an electrochemical rebalancing method that extends cell lifetime by recovering the initial electrolyte composition after it is perturbed by side reactions. We discuss the implications of these results for future low-energy electrochemical carbon capture devices.

Frequency and Risk Factors for Difficult Intubation in Women Undergoing General Anesthesia for Cesarean Delivery: A Multicenter Retrospective Cohort Analysis.

BACKGROUND: Estimates for the incidence of difficult intubation in the obstetric population vary widely, although previous studies reporting rates of difficult intubation in obstetrics are older and limited by smaller samples. The goals of this study were to provide a contemporary estimate of the frequency of difficult and failed intubation in women undergoing general anesthesia for cesarean delivery and to elucidate risk factors for difficult intubation in women undergoing general anesthesia for cesarean delivery. METHODS: This is a multicenter, retrospective cohort study utilizing the Multicenter Perioperative Outcomes Group database. The study population included women aged 15 to 44 yr undergoing general anesthesia for cesarean delivery between 2004 and 2019 at 1 of 45 medical centers. Coprimary outcomes included the frequencies of difficult and failed intubation. Difficult intubation was defined as Cormack-Lehane view of 3 or greater, three or more intubation attempts, rescue fiberoptic intubation, rescue supraglottic airway, or surgical airway. Failed intubation was defined as any attempt at intubation without successful endotracheal tube placement. The rates of difficult and failed intubation were assessed. Several patient demographic, anatomical, and obstetric factors were evaluated for potential associations with difficult intubation. RESULTS: This study identified 14,748 cases of cesarean delivery performed under general anesthesia. There were 295 cases of difficult intubation, with a frequency of 1:49 (95% CI, 1:55 to 1:44; n = 14,531). There were 18 cases of failed intubation, with a frequency of 1:808 (95% CI, 1:1,276 to 1:511; n = 14,537). Factors with the highest point estimates for the odds of difficult intubation included increased body mass index, Mallampati score III or IV, small hyoid-to-mentum distance, limited jaw protrusion, limited mouth opening, and cervical spine limitations. CONCLUSIONS: In this large, multicenter, contemporary study of more than 14,000 general anesthetics for cesarean delivery, an overall risk of difficult intubation of 1:49 and a risk of failed intubation of 1:808 were observed. Most risk factors for difficult intubation were nonobstetric in nature. These data demonstrate that difficult intubation in obstetrics remains an ongoing concern.

Intensive care unit observation after pancreatectomy: Treating the patient or the surgeon?

BACKGROUND: Routine intensive care unit admission (ICUA) is commonplace following pancreatectomy, particularly pancreaticoduodenectomy. The value of this practice in avoiding failure-to-rescue is poorly studied. METHODS: We queried our institutional National Surgical Quality Improvement Project database for patients undergoing pancreatectomy from 2013 to 2020. Postoperative dispositions, ICU courses, and hospital cost data in United States Dollars (USD) were captured. Data were analyzed with multivariable logistic regression. RESULTS: Six-hundred-thirty-seven patients were identified; 404 (63%) underwent pancreaticoduodenectomy. Postoperatively, 398 (99%) pancreaticoduodenectomies and 110 (47%) distal pancreatectomies had ICUA; two-thirds (n = 318, 63%) did not require immediate postoperative ICU-level interventions at ICUA. Of these, 17 (5.3%) subsequently required ICU-level interventions during initial ICUA, most commonly antiarrhythmic infusion (n = 12). Thirty-day and 90-day mortality in patients requiring immediate ICU-level interventions was 5% (n = 10) and 8% (n = 16) versus 0.3% (n = 1) and 1.2% (n = 4) in those without, respectively. Hospital length of stay was significantly longer with initial ICU-level interventions (median 11 vs. 9 days, p < 0.001), as were total ICU costs (mean 8683 vs. 14611 USD, p < 0.001). CONCLUSION: At high-volume pancreas centers, patients without immediate postoperative ICU-level interventions are very low risk for failure-to-rescue. Ward admission with a low threshold for care escalation presents a significant opportunity for cost-savings and un-burdening ICUs.

Birthweight and Apgar at 5 minutes of life for the prediction of severe neonatal outcomes in preterm prelabor rupture of membranes.

OBJECTIVE: The aim of our study was to investigate the predictive accuracy of clinical variables available after delivery for severe neonatal outcomes (SNO) in pregnancies complicated by PPROM. MATERIALS AND METHODS: This was a secondary analysis of a prospective cohort of pregnancies complicated by PPROM. We included expectant mothers from 13-46 years of age who were between 23 and 36 6/7 weeks of gestation. We excluded multiple gestations, complex fetal anomalies, those with fetal demise and outborn infants. Our primary outcome was a composite of SNO (respiratory distress syndrome, necrotizing enterocolitis, Intra-ventricular hemorrhage, sepsis, and death). The variables assessed where gestational age at delivery, birthweight, Apgar score at 5 min of life, Apgar <7 at 5 min of life, small for gestational age, sex, umbilical artery pH, and mode of delivery. Logistic regression was performed to evaluate the predictive accuracy of each of these variables. Stepwise multivariable logistic regression was utilized to assess the effect of variables with univariate analysis p value <.10 and those baseline characteristics with a statistically significant association with our composite score. RESULTS: We included 108 infants. SNO was diagnosed in 44 (41%) neonates. The Apgar score at 5 min (AUC = 0.89; p= <.001), the birthweight (AUC = 0.88; p= <.001), gestational age at delivery (AUC = 0.87; p= <.001), and the Apgar score < 7 at 5 min (AUC = 0.73; p= <0.001) were statistical significant predictors of SNO. Sex (p=.15), mode of delivery (p=.15), umbilical artery Ph (p=.28), SGA (p=.85) were not statistically significant predictors of SNO. After stepwise multivariable logistic regression only the Apgar at 5 min and birth weight remained statistically significant predictors for SNO (AUC = 0.94). CONCLUSIONS: In pregnancies complicated by PPROM the birthweight and the Apgar at 5 min of life are accurate predictors of a composite score of SNO. We acknowledge the need for larger and more diverse studies to corroborate our findings. BRIEF RATIONALE: We assessed the predictive accuracy of clinical variables available after delivery for severe neonatal outcomes in pregnancies complicated by PPROM. We found that the birthweight and the Apgar score at 5 min were accurate predictors of such outcomes in this population. Our results may aid providers in the counseling of premature infants born after PPROM.

Alkalinity Concentration Swing for Direct Air Capture of Carbon Dioxide.

The alkalinity concentration swing (ACS) is a new process for direct air capture of carbon dioxide driven by concentrating an alkaline solution that has been exposed to the atmosphere and loaded with dissolved inorganic carbon. Upon concentration, the partial pressure of CO2 increases, allowing for extraction and compression. Higher concentration factors result in proportionally higher outgassing pressure, and higher initial alkalinity concentrations at the same concentration factor outgas a higher concentration of CO2 . Two desalination technologies, reverse osmosis and capacitive deionization, are examined as possible ACS implementations, and two corresponding energy models are evaluated. The ACS is compared to incumbent technologies and estimates for water, land, and energy requirements for capturing one million tonnes of CO2 per year are made. Estimates for the lower end of the energy range for both approaches compare favorably to other approaches, such as solid sorbent and calcining methods.

Expert Consensus Statement on the Perioperative Management of Adult Patients Undergoing Head and Neck Surgery and Free Tissue Reconstruction From the Society for Head and Neck Anesthesia.

The perioperative care of adult patients undergoing free tissue transfer during head and neck surgical (microvascular) reconstruction is inconsistent across practitioners and institutions. The executive board of the Society for Head and Neck Anesthesia (SHANA) nominated specialized anesthesiologists and head and neck surgeons to an expert group, to develop expert consensus statements. The group conducted an extensive review of the literature to identify evidence and gaps and to prioritize quality improvement opportunities. This report of expert consensus statements aims to improve and standardize perioperative care in this setting. The Modified Delphi method was used to evaluate the degree of agreement with draft consensus statements. Additional discussion and collaboration was performed via video conference and electronic communication to refine expert opinions and to achieve consensus on key statements. Thirty-one statements were initially formulated, 14 statements met criteria for consensus, 9 were near consensus, and 8 did not reach criteria for consensus. The expert statements reaching consensus described considerations for preoperative assessment and optimization, airway management, perioperative monitoring, fluid management, blood management, tracheal extubation, and postoperative care. This group also examined the role for vasopressors, communication, and other quality improvement efforts. This report provides the priorities and perspectives of a group of clinical experts to help guide perioperative care and provides actionable guidance for and opportunities for improvement in the care of patients undergoing free tissue transfer for head and neck reconstruction. The lack of consensus for some areas likely reflects differing clinical experiences and a limited available evidence base.

Difficult Airway Management in Adult Coronavirus Disease 2019 Patients: Statement by the Society of Airway Management.

The coronavirus disease 2019 (COVID-19) disease, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), often results in severe hypoxemia requiring airway management. Because SARS-CoV-2 virus is spread via respiratory droplets, bag-mask ventilation, intubation, and extubation may place health care workers (HCW) at risk. While existing recommendations address airway management in patients with COVID-19, no guidance exists specifically for difficult airway management. Some strategies normally recommended for difficult airway management may not be ideal in the setting of COVID-19 infection. To address this issue, the Society for Airway Management (SAM) created a task force to review existing literature and current practice guidelines for difficult airway management by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway. The SAM task force created recommendations for the management of known or suspected difficult airway in the setting of known or suspected COVID-19 infection. The goal of the task force was to optimize successful airway management while minimizing exposure risk. Each member conducted a literature review on specific clinical practice section utilizing standard search engines (PubMed, Ovid, Google Scholar). Existing recommendations and evidence for difficult airway management in the COVID-19 context were developed. Each specific recommendation was discussed among task force members and modified until unanimously approved by all task force members. Elements of Appraisal of Guidelines Research and Evaluation (AGREE) Reporting Checklist for dissemination of clinical practice guidelines were utilized to develop this statement. Airway management in the COVID-19 patient increases HCW exposure risk. Difficult airway management often takes longer and may involve multiple procedures with aerosolization potential, and strict adherence to personal protective equipment (PPE) protocols is mandatory to reduce risk to providers. When a patient's airway risk assessment suggests that awake tracheal intubation is an appropriate choice of technique, and procedures that may cause increased aerosolization of secretions should be avoided. Optimal preoxygenation before induction with a tight seal facemask may be performed to reduce the risk of hypoxemia. Unless the patient is experiencing oxygen desaturation, positive pressure bag-mask ventilation after induction may be avoided to reduce aerosolization. For optimal intubating conditions, patients should be anesthetized with full muscle relaxation. Videolaryngoscopy is recommended as a first-line strategy for airway management. If emergent invasive airway access is indicated, then we recommend a surgical technique such as scalpel-bougie-tube, rather than an aerosolizing generating procedure, such as transtracheal jet ventilation. This statement represents recommendations by the SAM task force for the difficult airway management of adults with COVID-19 with the goal to optimize successful airway management while minimizing the risk of clinician exposure.

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.