Pulse Oximetry and Race in Critically Ill Adults.

For critically ill adults, oxygen saturation is continuously monitored using pulse oximetry (Spo2) as a surrogate for arterial oxygen saturation (Sao2). Skin pigmentation may affect accuracy of Spo2 by introducing error from statistical bias, variance, or both. We evaluated relationships between race, Spo2, Sao2, and hypoxemia (Sao2 < 88%) or hyperoxemia (Pao2 > 150 mm Hg) among adults receiving mechanical ventilation in a medical ICU. DESIGN: Single-center, observational study. SETTING: Medical ICU at an academic medical center. PATIENTS: Critically ill adults receiving mechanical ventilation from July 2018 to February 2021, excluding patients with COVID-19, with race documented as Black or White in the electronic medical record, who had a pair of Spo2 and Sao2 measurements collected within 10 minutes of each other. INTERVENTIONS: None. MEASUREMENTS: We included 1,024 patients with 5,557 paired measurements within 10 minutes, of which 3,885 (70%) were within 1 minute. Of all pairs, 769 (14%) were from Black patients and 4,788 (86%) were from White patients. In analyses using a mixed-effects model, we found that across the range of Spo2 values of 92-98%, the associated Sao2 value was approximately 1% point lower for Black patients compared with White patients. Among patients with a Spo2 value between 92% and 96%, Black patients were more likely to have both hypoxemia (3.5% vs 1.1%; p = 0.002) and hyperoxemia (4.7% vs 2.4%; p = 0.03), compared with White patients. CONCLUSIONS: Among patients with a measured Spo2 of 92-96%, greater variation in Sao2 values at a given Spo2 resulted in a higher occurence rate of both hypoxemia and hyperoxemia for Black patients compared with White patients.

Advances in Sepsis Care.

This review article summarizes current scientific evidence regarding the treatment of sepsis. We highlight recent advances in sepsis management with a focus on antibiotics, fluids, vasopressors, and adjunctive therapies such as corticosteroids and renal replacement therapy.

Effect of Use of a Bougie vs Endotracheal Tube With Stylet on Successful Intubation on the First Attempt Among Critically Ill Patients Undergoing Tracheal Intubation: A Randomized Clinical Trial.

Importance: For critically ill adults undergoing emergency tracheal intubation, failure to intubate the trachea on the first attempt occurs in up to 20% of cases and is associated with severe hypoxemia and cardiac arrest. Whether using a tracheal tube introducer ("bougie") increases the likelihood of successful intubation compared with using an endotracheal tube with stylet remains uncertain. Objective: To determine the effect of use of a bougie vs an endotracheal tube with stylet on successful intubation on the first attempt. Design, Setting, and Participants: The Bougie or Stylet in Patients Undergoing Intubation Emergently (BOUGIE) trial was a multicenter, randomized clinical trial among 1102 critically ill adults undergoing tracheal intubation in 7 emergency departments and 8 intensive care units in the US between April 29, 2019, and February 14, 2021; the date of final follow-up was March 14, 2021. Interventions: Patients were randomly assigned to use of a bougie (n = 556) or use of an endotracheal tube with stylet (n = 546). Main Outcomes and Measures: The primary outcome was successful intubation on the first attempt. The secondary outcome was the incidence of severe hypoxemia, defined as a peripheral oxygen saturation less than 80%. Results: Among 1106 patients randomized, 1102 (99.6%) completed the trial and were included in the primary analysis (median age, 58 years; 41.0% women). Successful intubation on the first attempt occurred in 447 patients (80.4%) in the bougie group and 453 patients (83.0%) in the stylet group (absolute risk difference, -2.6 percentage points [95% CI, -7.3 to 2.2]; P = .27). A total of 58 patients (11.0%) in the bougie group experienced severe hypoxemia, compared with 46 patients (8.8%) in the stylet group (absolute risk difference, 2.2 percentage points [95% CI, -1.6 to 6.0]). Esophageal intubation occurred in 4 patients (0.7%) in the bougie group and 5 patients (0.9%) in the stylet group, pneumothorax was present after intubation in 14 patients (2.5%) in the bougie group and 15 patients (2.7%) in the stylet group, and injury to oral, glottic, or thoracic structures occurred in 0 patients in the bougie group and 3 patients (0.5%) in the stylet group. Conclusions and Relevance: Among critically ill adults undergoing tracheal intubation, use of a bougie did not significantly increase the incidence of successful intubation on the first attempt compared with use of an endotracheal tube with stylet. Trial Registration: ClinicalTrials.gov Identifier: NCT03928925

Linear Association Between Hypoalbuminemia and Increased Risk of Acute Respiratory Distress Syndrome in Critically Ill Adults.

We hypothesized that low serum albumin would contribute to pulmonary edema formation, thereby independently increasing the risk of developing acute respiratory distress syndrome in critically ill patients. DESIGN: Retrospective analysis of prospective cohort. SETTING: Medical, surgical, and cardiovascular ICUs at Vanderbilt University Medical Center. PATIENTS: Patients (n = 993) with serum albumin measured for clinical reasons within 24 hours of study enrollment on ICU day 2 were included. MEASUREMENTS AND MAIN RESULTS: The primary outcome was presence of acute respiratory distress syndrome at any time during the first 4 days in the ICU, as defined by the Berlin definition. Secondary outcomes included ventilator-free days and ICU length of stay. In an unadjusted analysis, lower serum albumin levels were associated with a higher occurrence rate of acute respiratory distress syndrome (p < 0.001). In a multivariable analysis controlling for prespecified confounders, lower serum albumin was independently associated with an increased risk of acute respiratory distress syndrome (odds ratio, 1.48 per 1-g/dL decrease in albumin; 95% CI, 1.14-1.94; p = 0.004). Additionally, lower serum albumin was associated with increased mortality (odds ratio, 1.56 per 1-g/dL decrease in albumin; 95% CI, 1.19-2.04; p = 0.001), increased ICU length of stay (incidence rate ratio, 1.19; 95% CI, 1.15-1.23; p < 0.001), higher Sequential Organ Failure Assessment score (p < 0.001), and fewer ventilator-free days (incidence rate ratio, 1.21; 95% CI, 1.19-1.24; p < 0.001). CONCLUSIONS: Among adult ICU patients, lower serum albumin was independently associated with increased risk of acute respiratory distress syndrome after controlling for severity of illness and potential confounders. These findings support the hypothesis that low plasma oncotic pressure contributes to pulmonary edema formation in patients at risk for acute respiratory distress syndrome, independent of severity of illness.

Protocolized Postextubation Respiratory Support to Prevent Reintubation: A Randomized Clinical Trial.

Rationale: Respiratory support (noninvasive ventilation or high-flow nasal cannula) applied at the time of extubation has been reported to reduce reintubation rates, but concerns regarding effectiveness have limited uptake into practice.Objectives: To determine if providing postextubation respiratory support to all patients undergoing extubation in a medical ICU would decrease the incidence of reintubation.Methods: We conducted a pragmatic, two-armed, cluster-crossover trial of adults undergoing extubation from invasive mechanical ventilation between October 1, 2017, and March 31, 2019, in the medical ICU of an academic medical center. Patients were assigned to either protocolized postextubation respiratory support (a respiratory therapist-driven protocol in which patients with suspected hypercapnia received noninvasive ventilation and patients without suspected hypercapnia received high-flow nasal cannula) or usual care (postextubation management at the discretion of treating clinicians). The primary outcome was reintubation within 96 hours of extubation.Measurements and Main Results: A total of 751 patients were enrolled. Of the 359 patients assigned to protocolized support, 331 (92.2%) received postextubation respiratory support compared with 66 of 392 patients (16.8%) assigned to usual care, a difference driven by differential use of high-flow nasal cannula (74.7% vs. 2.8%). A total of 57 patients (15.9%) in the protocolized support group experienced reintubation compared with 52 patients (13.3%) in the usual care group (odds ratio, 1.23; 95% confidence interval, 0.82 to 1.84; P = 0.32).Conclusions: Among a broad population of critically ill adults undergoing extubation from invasive mechanical ventilation at an academic medical center, protocolized postextubation respiratory support, primarily characterized by an increase in the use of high-flow nasal cannula, did not prevent reintubation compared with usual care.Clinical trial registered with www.clinicaltrials.gov (NCT0328831).

Effect of balanced crystalloids versus saline on urinary biomarkers of acute kidney injury in critically ill adults.

BACKGROUND: Recent trials have suggested use of balanced crystalloids may decrease the incidence of major adverse kidney events compared to saline in critically ill adults. The effect of crystalloid composition on biomarkers of early acute kidney injury remains unknown. METHODS: From February 15 to July 15, 2016, we conducted an ancillary study to the Isotonic Solutions and Major Adverse Renal Events Trial (SMART) comparing the effect of balanced crystalloids versus saline on urinary levels of neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1) among 261 consecutively-enrolled critically ill adults admitted from the emergency department to the medical ICU. After informed consent, we collected urine 36 ± 12 h after hospital admission and measured NGAL and KIM-1 levels using commercially available ELISAs. Levels of NGAL and KIM-1 at 36 ± 12 h were compared between patients assigned to balanced crystalloids versus saline using a Mann-Whitney U test. RESULTS: The 131 patients (50.2%) assigned to the balanced crystalloid group and the 130 patients (49.8%) assigned to the saline group were similar at baseline. Urinary NGAL levels were significantly lower in the balanced crystalloid group (median, 39.4 ng/mg [IQR 9.9 to 133.2]) compared with the saline group (median, 64.4 ng/mg [IQR 27.6 to 339.9]) (P < 0.001). Urinary KIM-1 levels did not significantly differ between the balanced crystalloid group (median, 2.7 ng/mg [IQR 1.5 to 4.9]) and the saline group (median, 2.4 ng/mg [IQR 1.3 to 5.0]) (P = 0.36). CONCLUSIONS: In this ancillary analysis of a clinical trial comparing balanced crystalloids to saline among critically ill adults, balanced crystalloids were associated with lower urinary concentrations of NGAL and similar urinary concentrations of KIM-1, compared with saline. These results suggest only a modest reduction in early biomarkers of acute kidney injury with use of balanced crystalloids compared with saline. TRIAL REGISTRATION: ClinicalTrials.gov number: NCT02444988 . Date registered: May 15, 2015.

Effect of Early Balanced Crystalloids Before ICU Admission on Sepsis Outcomes.

BACKGROUND: Studies suggest that using balanced crystalloids (lactated Ringer's solution or Plasma-Lyte A) rather than saline (0.9% sodium chloride) may improve outcomes for patients with sepsis in the ED and ICU. RESEARCH QUESTION: What is the relative impact on sepsis outcomes of fluid composition during early resuscitation in the ED vs after ICU admission? STUDY DESIGN AND METHODS: We performed a secondary analysis of the Isotonic Solutions and Major Adverse Renal Events Trial (SMART) data set, examining medical ICU patients with a diagnosis of sepsis (n = 1,641). SMART was a cluster-crossover trial comparing balanced crystalloids vs saline among critically ill adults. During the first 7 months of SMART, fluid choice was controlled only in the ICU ("ICU-only period"). In the final 15 months, fluid choice was coordinated between the ED and ICU ("ED and ICU period"). We performed logistic regression modeling for 30-day in-hospital mortality with an interaction term between randomized group (balanced crystalloids vs saline) and study period (ICU-only period vs ED and ICU period). RESULTS: Three hundred and sixty-seven patients with sepsis were enrolled during the ICU-only period and 1,274 were enrolled during the ED and ICU period. Thirty-day in-hospital mortality occurred in 47 of 142 patients (33.1%) in the balanced crystalloid group vs 74 of 225 patients (32.9%) in the saline group during the ICU-only period (OR, 1.14; 95% CI, 0.70-1.88) and in 170 of 682 patients (24.9%) in the balanced crystalloid group vs 181 of 592 patients (30.6%) in the saline group in the ED and ICU period (OR, 0.68; 95% CI, 0.52-0.89) (P value for interaction, .07), consistent with a beneficial effect of balanced crystalloid primarily in the ED and ICU period. INTERPRETATION: Among patients with sepsis, the effect of balanced crystalloids vs saline on mortality was greater among patients for whom fluid choice was controlled starting in the ED compared with starting in the ICU.

Advances in Rotorcraft Crashworthiness - Trends Leading to Improved Survivability.

This paper documents progress in rotorcraft crashworthiness research and development that has been realized during the past forty years. Trends are presented in several categories including: facilities and equipment for conducting crash testing, updated crash certification requirements, the application of crash modeling and simulation techniques, and rotorcraft structural design for improved crash performance focusing on the application of advanced composite materials. Likely one of the most important advances is the ability to rapidly simulate crash impacts and to see the effects of design changes on the impact response. Enhanced dynamic computer simulations have greatly improved automotive safety today and are making inroads in the aerospace community. Consequently, a detailed discussion of advances in crash modeling and simulation is presented. The paper concludes with a list of suggested recommendations, such that the progress made to date can be continued into the future.

Patch-Burn Grazing Effects on the Ecological Integrity of Tallgrass Prairie Streams.

Conversion to agriculture, habitat fragmentation, and the loss of native grazers have made tallgrass prairie one of the most endangered ecosystems. One management option for the remaining prairie parcels, patch-burn grazing (PBG), applies a controlled burn to a portion of the prairie to attract cattle, creating a mosaic of more- and less-grazed patches. Although beneficial to cattle and grassland birds, the potential impacts of PBG on streams have not been studied, and a holistic approach is needed to ensure against adverse effects. We used a Before-After-Control-Impact design to assess potential impacts of PBG with and without riparian protection on tallgrass prairie headwater streams. We sampled stream macroinvertebrates and benthic organic matter 2 yr before and 2 yr during PBG treatments on two grazed watersheds with riparian fencing (fenced), two unfenced grazed watersheds (unfenced), and two ungrazed (control) watersheds. Very fine benthic organic matter increased significantly (51%) in unfenced streams compared with controls ( < 0.007), and fine particulate organic matter (<1 mm and >250 µm) increased 3-fold in the unfenced streams compared with controls ( = 0.008). The contribution of fine inorganic sediments to total substrata increased 28% in unfenced streams during PBG, which was significantly different from controls ( = 0.03). Additionally, the abundance of Ephemeroptera, Plecoptera, and Trichoptera taxa decreased from 7635 to 687 individuals m in unfenced streams, which was significantly lower than in control streams ( = 0.008). Our results indicate that PBG adversely influences prairie streams through sediment inputs and reductions in sensitive invertebrate taxa, but riparian fencing can alleviate these impacts.

Ecosystem characteristics of remnant, headwater tallgrass prairie streams.

North America has lost >95% of its native tallgrass prairie due to land conversion, making prairie streams one of the most endangered ecosystems. Research on the basic ecosystem characteristics of the remaining natural prairie streams will inform conservation and management. We examined the structure and function of headwater streams draining tallgrass prairie tracts at Osage Prairie in Missouri and the Konza Prairie Biological Station in Kansas and compared those values with literature values for streams draining agricultural watersheds in the region. We quantified physicochemical and biological characteristics for 2 yr. Streams at Osage and Konza were characterized by low nutrients and low suspended sediments (substantially lower than impacted sites in the region), slight heterotrophic status, and high temporal variability. Suspended sediments and nutrient concentrations were generally low in all prairie streams, but storms increased concentrations of both by 3- to 12-fold. Spring prescribed burns were followed by a slight increase in chlorophyll and decreased nutrients, potentially due to greater light availability. Benthic macroinvertebrate communities at Osage showed seasonal patterns that were probably linked to variable hydrology. We found nine amphibian species using the Osage streams as habitat or breeding sites, but little usage at Konza was probably due to dry conditions and low discharge. Our study indicates that two remnant tallgrass prairie streams along a longitudinal gradient are fairly similar in terms of physicochemical features and have good water quality relative to agricultural watersheds but can differ considerably in macroinvertebrate and amphibian abundance.

The Sisters Network: A National African American Breast Cancer Survivor Advocacy Organization.

Founded in 1994 by an African American woman who was diagnosed with breast cancer only a few months earlier, the Sisters Network advocacy organization today has nearly 3,000 members in 35 chapters throughout the country.