Just Say NO: Inhaled Nitric Oxide Effect on Respiratory Parameters Following Traumatic Brain Injury in Humans and a Porcine Model.

INTRODUCTION: The mechanism of post-traumatic brain injury (TBI) hypoxemia involves ventilation/perfusion mismatch and loss of pulmonary hypoxic vasoconstriction. Inhaled nitric oxide (iNO) has been studied as an adjunct treatment to avoid the use of high positive end-expiratory pressure and inspired oxygen in treatment-refractory hypoxia. We hypothesized that iNO treatment following TBI would improve systemic and cerebral oxygenation via improved matching of pulmonary perfusion and ventilation. METHODS: Thirteen human patients with isolated TBI were enrolled and randomized to receive either placebo or iNO with measured outcomes including pulmonary parameters, blood gas data, and intracranial pressure (ICP) /perfusion. To complement this study, a porcine model of TBI (including 10 swine) was utilized with measured outcomes of brain tissue blood flow and oxygenation, ventilator parameters, and blood gas data both after administration and following drug removal and clearance. RESULTS: There were no clinically significant changes in pulmonary parameters in either the human or porcine arm following administration of iNO when compared to either the placebo group (human arm) or the internal control (porcine arm). Analysis of pooled human data demonstrated the preservation of alveolar recruitment in TBI patients. There were no clinically significant changes in human ICP or cerebral perfusion pressure following iNO administration compared to controls. CONCLUSIONS: iNO had no significant effect on clinically relevant pulmonary parameters or ICPs following TBI in both human patients and a porcine model. The pressure-based recruitment of the human lungs following TBI was preserved. Further investigation will be needed to determine the degree of utility of iNO in the setting of hypoxia after polytrauma.

The Reviewer Academy of the Society of Critical Care Medicine: Key Principles and Strategic Plan.

The Society of Critical Care Medicine (SCCM) Reviewer Academy seeks to train and establish a community of trusted, reliable, and skilled peer reviewers with diverse backgrounds and interests to promote high-quality reviews for each of the SCCM journals. Goals of the Academy include building accessible resources to highlight qualities of excellent manuscript reviews; educating and mentoring a diverse group of healthcare professionals; and establishing and upholding standards for insightful and informative reviews. This manuscript will map the mission of the Reviewer Academy with a succinct summary of the importance of peer review, process of reviewing a manuscript, and the expected ethical standards of reviewers. We will equip readers to target concise, thoughtful feedback as peer reviewers, advance their understanding of the editorial process and inspire readers to integrate medical journalism into diverse professional careers.

Antimicrobial Coating Prevents Ventilator-Associated Pneumonia in a 72 hour Large Animal Model.

BACKGROUND: The primary goal of this study was to demonstrate that endotracheal tubes coated with antimicrobial lipids plus mucolytic or antimicrobial lipids with antibiotics plus mucolytic would significantly reduce pneumonia in the lungs of pigs after 72 hours of continuous mechanical ventilation compared to uncoated controls. MATERIALS AND METHODS: Eighteen female pigs were mechanically ventilated for up to 72 hours through uncoated endotracheal tubes, endotracheal tubes coated with the antimicrobial lipid, octadecylamine, and the mucolytic, N-acetylcysteine, or tubes coated with octadecylamine, N-acetylcysteine, doxycycline, and levofloxacin (6 pigs per group). No exogenous bacteria were inoculated into the pigs, pneumonia resulted from the pigs' endogenous oral flora. Vital signs were recorded every 15 minutes and arterial blood gas measurements were obtained for the duration of the experiment. Pigs were sacrificed either after completion of 72 hours of mechanical ventilation or just prior to hypoxic arrest. Lungs, trachea, and endotracheal tubes were harvested for analysis to include bacterial counts of lung, trachea, and endotracheal tubes, lung wet and dry weights, and lung tissue for histology. RESULTS: Pigs ventilated with coated endotracheal tubes were less hypoxic, had less bacterial colonization of the lungs, and survived significantly longer than pigs ventilated with uncoated tubes. Octadecylamine-N-acetylcysteine-doxycycline-levofloxacin coated endotracheal tubes had less bacterial colonization than uncoated or octadecylamine-N-acetylcysteine coated tubes. CONCLUSION: Endotracheal tubes coated with antimicrobial lipids plus mucolytic and antimicrobial lipids with antibiotics plus mucolytic reduced bacterial colonization of pig lungs after prolonged mechanical ventilation and may be an effective strategy to reduce ventilator-associated pneumonia.

Long-Term Noninvasive Ventilation in Chronic Stable Hypercapnic Chronic Obstructive Pulmonary Disease. An Official American Thoracic Society Clinical Practice Guideline.

Background: Noninvasive ventilation (NIV) is used for patients with chronic obstructive pulmonary disease (COPD) and chronic hypercapnia. However, evidence for clinical efficacy and optimal management of therapy is limited.Target Audience: Patients with COPD, clinicians who care for them, and policy makers.Methods: We summarized evidence addressing five PICO (patients, intervention, comparator, and outcome) questions. The GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) approach was used to evaluate the certainty in evidence and generate actionable recommendations. Recommendations were formulated by a panel of pulmonary and sleep physicians, respiratory therapists, and methodologists using the Evidence-to-Decision framework.Recommendations:1) We suggest the use of nocturnal NIV in addition to usual care for patients with chronic stable hypercapnic COPD (conditional recommendation, moderate certainty); 2) we suggest that patients with chronic stable hypercapnic COPD undergo screening for obstructive sleep apnea before initiation of long-term NIV (conditional recommendation, very low certainty); 3) we suggest not initiating long-term NIV during an admission for acute-on-chronic hypercapnic respiratory failure, favoring instead reassessment for NIV at 2-4 weeks after resolution (conditional recommendation, low certainty); 4) we suggest not using an in-laboratory overnight polysomnogram to titrate NIV in patients with chronic stable hypercapnic COPD who are initiating NIV (conditional recommendation, very low certainty); and 5) we suggest NIV with targeted normalization of PaCO2 in patients with hypercapnic COPD on long-term NIV (conditional recommendation, low certainty).Conclusions: This expert panel provides evidence-based recommendations addressing the use of NIV in patients with COPD and chronic stable hypercapnic respiratory failure.

Coronavirus Disease 2019 Pandemic Measures: Reports From a National Survey of 9,120 ICU Clinicians.

IMPORTANCE: Recent reports identify that among hospitalized coronavirus disease 2019 patients, 30% require ICU care. Understanding ICU resource needs remains an essential component of meeting current and projected needs of critically ill coronavirus disease 2019 patients. OBJECTIVES: This study queried U.S. ICU clinician perspectives on challenging aspects of care in managing coronavirus disease 2019 patients, current and anticipated resource demands, and personal stress. DESIGN, SETTING, AND PARTICIPANTS: Using a descriptive survey methodology, an anonymous web-based survey was administered from April 7, 2020, to April 22, 2020 (email and newsletter) to query members of U.S. national critical care organizations. MEASUREMENTS AND MAIN RESULTS: Through a 16-item descriptive questionnaire, ICU clinician perceptions were assessed regarding current and emerging critical ICU needs in managing the severe acute respiratory syndrome coronavirus 2 infected patients, resource levels, concerns about being exposed to severe acute respiratory syndrome coronavirus 2, and perceived level of personal stress. A total of 9,120 ICU clinicians responded to the survey, representing all 50 U.S. states, with 4,106 (56.9%) working in states with 20,000 or more coronavirus disease 2019 cases. The 7,317 respondents who indicated their profession included ICU nurses (n = 6,731, 91.3%), advanced practice providers (nurse practitioners and physician assistants; n = 334, 4.5%), physicians (n = 212, 2.9%), respiratory therapists (n = 31, 0.4%), and pharmacists (n = 30, 0.4%). A majority (n = 6,510, 88%) reported having cared for a patient with presumed or confirmed coronavirus disease 2019. The most critical ICU needs identified were personal protective equipment, specifically N95 respirator availability, and ICU staffing. Minimizing healthcare worker virus exposure during care was believed to be the most challenging aspect of coronavirus disease 2019 patient care (n = 2,323, 30.9%). Nurses report a high level of concern about exposing family members to severe acute respiratory syndrome coronavirus 2 (median score of 10 on 0-10 scale). Similarly, the level of concern reached the maximum score of 10 in ICU clinicians who had provided care to coronavirus disease 2019 patients. CONCLUSIONS: This national ICU clinician survey identifies continued concerns regarding personal protective equipment supplies with the chief issue being N95 respirator availability. As the pandemic continues, ICU clinicians anticipate a number of limited resources that may impact ICU care including personnel, capacity, and surge potential, as well as staff and subsequent family members exposure to severe acute respiratory syndrome coronavirus 2. These persistent concerns greatly magnify personal stress, offering a therapeutic target for professional organization and facility intervention efforts.

Development and Reporting of Prediction Models: Guidance for Authors From Editors of Respiratory, Sleep, and Critical Care Journals.

Prediction models aim to use available data to predict a health state or outcome that has not yet been observed. Prediction is primarily relevant to clinical practice, but is also used in research, and administration. While prediction modeling involves estimating the relationship between patient factors and outcomes, it is distinct from casual inference. Prediction modeling thus requires unique considerations for development, validation, and updating. This document represents an effort from editors at 31 respiratory, sleep, and critical care medicine journals to consolidate contemporary best practices and recommendations related to prediction study design, conduct, and reporting. Herein, we address issues commonly encountered in submissions to our various journals. Key topics include considerations for selecting predictor variables, operationalizing variables, dealing with missing data, the importance of appropriate validation, model performance measures and their interpretation, and good reporting practices. Supplemental discussion covers emerging topics such as model fairness, competing risks, pitfalls of "modifiable risk factors", measurement error, and risk for bias. This guidance is not meant to be overly prescriptive; we acknowledge that every study is different, and no set of rules will fit all cases. Additional best practices can be found in the Transparent Reporting of a multivariable prediction model for Individual Prognosis Or Diagnosis (TRIPOD) guidelines, to which we refer readers for further details.

Ketamine versus hydromorphone patient-controlled analgesia for acute pain in trauma patients.

BACKGROUND: It is unknown whether ketamine administered via patient-controlled analgesia (PCA) provides adequate analgesia while reducing opioid consumption in the traumatically injured patient. Differences in opioid consumption, pain scores, and adverse effects between ketamine and hydromorphone PCA were studied. MATERIALS AND METHODS: This is an investigator-initiated, single-center, double-blinded, randomized, pilot trial conducted from 2014 to 2016 at a level 1 trauma center. Nonintubated trauma patients in intensive care, who were receiving PCA, were randomized to ketamine or hydromorphone PCA plus opioid analgesics for breakthrough pain. RESULTS: Twenty subjects were randomized. There was no difference in median daily breakthrough opioid use (10 [0.63-19.38] mg versus 10 [4.38-22.5] mg, P = 0.55). Subjects in the ketamine group had lower median cumulative opioid use on therapy day 1 than the hydromorphone group (4.6 [2.5-15] mg versus 41.8 [31.8-50] mg, P < 0.001), as well as in the first 48 h (10 [3.3-15] mg versus 48.5 [32.1-67.5] mg, P < 0.001) and first 72 h (10 [4.2-15] mg versus 42.5 [31.7-65.2] mg, P < 0.001) of therapy. Daily oxygen supplementation requirements were lower in the ketamine group (0.5 [0-1.5] L/min versus 2 [0.5-3] L/min, P = 0.020). Hallucinations occurred more frequently in the ketamine group (40% versus 0%, P = 0.090). CONCLUSIONS: Ketamine PCA led to lower cumulative opioid consumption and lower oxygen supplementation requirements, though hallucinations occurred more frequently with use of ketamine. Additional studies are needed to investigate the tolerability of ketamine as an alternative to traditional opioid-based PCA.

An Official American Thoracic Society/European Society of Intensive Care Medicine/Society of Critical Care Medicine Clinical Practice Guideline: Mechanical Ventilation in Adult Patients with Acute Respiratory Distress Syndrome.

BACKGROUND: This document provides evidence-based clinical practice guidelines on the use of mechanical ventilation in adult patients with acute respiratory distress syndrome (ARDS). METHODS: A multidisciplinary panel conducted systematic reviews and metaanalyses of the relevant research and applied Grading of Recommendations, Assessment, Development, and Evaluation methodology for clinical recommendations. RESULTS: For all patients with ARDS, the recommendation is strong for mechanical ventilation using lower tidal volumes (4-8 ml/kg predicted body weight) and lower inspiratory pressures (plateau pressure < 30 cm H2O) (moderate confidence in effect estimates). For patients with severe ARDS, the recommendation is strong for prone positioning for more than 12 h/d (moderate confidence in effect estimates). For patients with moderate or severe ARDS, the recommendation is strong against routine use of high-frequency oscillatory ventilation (high confidence in effect estimates) and conditional for higher positive end-expiratory pressure (moderate confidence in effect estimates) and recruitment maneuvers (low confidence in effect estimates). Additional evidence is necessary to make a definitive recommendation for or against the use of extracorporeal membrane oxygenation in patients with severe ARDS. CONCLUSIONS: The panel formulated and provided the rationale for recommendations on selected ventilatory interventions for adult patients with ARDS. Clinicians managing patients with ARDS should personalize decisions for their patients, particularly regarding the conditional recommendations in this guideline.

Chiropractic Integrated Care Pathway for Low Back Pain in Veterans: Results of a Delphi Consensus Process.

OBJECTIVE: The purpose of this study was to develop an integrated care pathway for doctors of chiropractic, primary care providers, and mental health professionals who manage veterans with low back pain, with or without mental health comorbidity, within Department of Veterans Affairs health care facilities. METHODS: The research method used was a consensus process. A multidisciplinary investigative team reviewed clinical guidelines and Veterans Affairs pain and mental health initiatives to develop seed statements and care algorithms to guide chiropractic management and collaborative care of veterans with low back pain. A 5-member advisory committee approved initial recommendations. Veterans Affairs-based panelists (n = 58) evaluated the pathway via e-mail using a modified RAND/UCLA methodology. Consensus was defined as agreement by 80% of panelists. RESULTS: The modified Delphi process was conducted in July to December 2016. Most (93%) seed statements achieved consensus during the first round, with all statements reaching consensus after 2 rounds. The final care pathway addressed the topics of informed consent, clinical evaluation including history and examination, screening for red flags, documentation, diagnostic imaging, patient-reported outcomes, adverse event reporting, chiropractic treatment frequency and duration standards, tailored approaches to chiropractic care in veteran populations, and clinical presentation of common mental health conditions. Care algorithms outlined chiropractic case management and interprofessional collaboration and referrals between doctors of chiropractic and primary care and mental health providers. CONCLUSION: This study offers an integrative care pathway that includes chiropractic care for veterans with low back pain.

Association of Spinal Manipulative Therapy With Clinical Benefit and Harm for Acute Low Back Pain: Systematic Review and Meta-analysis.

IMPORTANCE: Acute low back pain is common and spinal manipulative therapy (SMT) is a treatment option. Randomized clinical trials (RCTs) and meta-analyses have reported different conclusions about the effectiveness of SMT. OBJECTIVE: To systematically review studies of the effectiveness and harms of SMT for acute (≤6 weeks) low back pain. DATA SOURCES: Search of MEDLINE, Cochrane Database of Systematic Reviews, EMBASE, and Current Nursing and Allied Health Literature from January 1, 2011, through February 6, 2017, as well as identified systematic reviews and RCTs, for RCTs of adults with low back pain treated in ambulatory settings with SMT compared with sham or alternative treatments, and that measured pain or function outcomes for up to 6 weeks. Observational studies were included to assess harms. DATA EXTRACTION AND SYNTHESIS: Data extraction was done in duplicate. Study quality was assessed using the Cochrane Back and Neck (CBN) Risk of Bias tool. This tool has 11 items in the following domains: randomization, concealment, baseline differences, blinding (patient), blinding (care provider [care provider is a specific quality metric used by the CBN Risk of Bias tool]), blinding (outcome), co-interventions, compliance, dropouts, timing, and intention to treat. Prior research has shown the CBN Risk of Bias tool identifies studies at an increased risk of bias using a threshold of 5 or 6 as a summary score. The evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) criteria. MAIN OUTCOMES AND MEASURES: Pain (measured by either the 100-mm visual analog scale, 11-point numeric rating scale, or other numeric pain scale), function (measured by the 24-point Roland Morris Disability Questionnaire or Oswestry Disability Index [range, 0-100]), or any harms measured within 6 weeks. FINDINGS: Of 26 eligible RCTs identified, 15 RCTs (1711 patients) provided moderate-quality evidence that SMT has a statistically significant association with improvements in pain (pooled mean improvement in the 100-mm visual analog pain scale, -9.95 [95% CI, -15.6 to -4.3]). Twelve RCTs (1381 patients) produced moderate-quality evidence that SMT has a statistically significant association with improvements in function (pooled mean effect size, -0.39 [95% CI, -0.71 to -0.07]). Heterogeneity was not explained by type of clinician performing SMT, type of manipulation, study quality, or whether SMT was given alone or as part of a package of therapies. No RCT reported any serious adverse event. Minor transient adverse events such as increased pain, muscle stiffness, and headache were reported 50% to 67% of the time in large case series of patients treated with SMT. CONCLUSIONS AND RELEVANCE: Among patients with acute low back pain, spinal manipulative therapy was associated with modest improvements in pain and function at up to 6 weeks, with transient minor musculoskeletal harms. However, heterogeneity in study results was large.

Evaluation of Intensive Care Unit Ventilators at Altitude.

INTRODUCTION: Devices may forgo US military air worthiness and safety testing in an attempt to expedite the availability of critical assets such as mechanical ventilators with a waiver for one-time use in extenuating circumstances. METHODS: We evaluated two Intensive Care Unit (ICU) level ventilators: Drager Evita XL and Puritan Bennett (PB) 840 in an altitude chamber at sea level and altitudes of 8,000 and 16,000 feet. RESULTS: Altitude affected delivered tidal volumes (VTs) in volume control mode (VCV) and Pressure Regulated Volume Controlled (PRVC) mode at altitude with the Evita XL but the differences were not considered clinically important with the PB 840. Sixty-seven percent of the VTs were outside the ASTM standard of ± 10% of set VT with the Evita XL at altitude. CONCLUSION: The PB 840 did not deliver VTs that were larger than the ASTM standard up to an altitude of 16,000 feet while the majority of the delivered VTs with the Därger XL were greater than the ASTM standard. This could present a patient safety issue. Caregivers must be aware of the capabilities and limitations of ICU ventilators when utilized in a hypobaric environment in order to provide safe care.

Evaluation of a volume targeted NIV device: bench evaluation of the Breathe Technologies non-invasive open ventilation system (NIOV™).

PURPOSE: Early ambulation in the ventilated patient is gaining wider acceptance. We evaluated a new portable (1 lb), gas powered, volume ventilator designed for NIV via a proprietary nasal pillows interface (Breathe Technologies, CA). METHODS: We developed a model to approximate a patient's nose, upper airway and trachea. The model was connected to a test lung (ASL5000, Ingmar Medical, Pittsburgh, PA) via 22 mm ID corrugated tubing. The nasal pillows were adjusted in the nares using a lanyard. The ASL was set to represent a normal patient, a COPD patient, and a patient with interstitial lung disease (ILD). The Breathe ventilator was set at delivered volumes of 100 mL, 150 mL, 200 mL, and 250 mL. Baseline data was also collected without the appliance connected. Delivered volume, inspired oxygen concentration (FIO2), inspiratory flow (V), and peak inspiratory pressure (PIP) were recorded for each breath. Data for 10 breaths were used to calculate the mean at each condition (± SD). RESULTS: The Breathe volume ventilator delivered an augmented simulated patient tidal volume of 362 to 823 mL, augmenting the simulated patient's spontaneous volume by up to 459 mL, depending on ventilator settings and ASL lung conditions. Delivered FIO2 ranged from 0.36 to 0.45 and was also dependent on ventilator settings and ASL lung conditions. CONCLUSIONS: The PIP, delivered tidal volumes, and measured FIO2 support the hypothesis that this system can augment minute ventilation and supply supplemental oxygen in spontaneously breathing patients with a simple, non-invasive interface.

Evaluation of a Rebreathing System for Use with Portable Mechanical Ventilators.

INTRODUCTION: Maximizing the capabilities of available lowflow oxygen is key to providing adequate oxygen to prevent/treat hypoxemia and conserve oxygen. We designed a closed-circuit system that allows rebreathing of gases while scrubbing carbon dioxide (CO2) in conjunction with portable mechanical ventilators in a bench model. METHODS: We evaluated the system using two portable mechanical ventilators currently deployed by the Department of Defense-Zoll 731 and AutoMedx SAVe II-over a range of ventilator settings and lung models, using 1 and 3L/min low-flow oxygen into a reservoir bag. We measured peak inspired oxygen concentration (FiO2), CO2-absorbent life, gas temperature and humidity, and the effect of airway suctioning and ventilator disconnection on FiO2 on ground and at altitude. RESULTS: FiO2 was =0.9 across all ventilator settings and altitudes using both oxygen flows. CO2-absorbent life was >7 hours. Airway humidity range was 87%-97%. Mean airway temperature was 25.4°C (SD 0.5°C). Ten-second suctioning reduced FiO2 22%-48%. Thirtysecond ventilator disconnect reduced FiO2 29%-63% depending on oxygen flow used. CONCLUSION: Use of a rebreathing system with mechanical ventilation has the potential for oxygen conservation but requires diligent monitoring of inspired FiO2 and CO2 to avoid negative consequences.

Evaluation of Inhaled Nitric Oxide Generation Systems at Altitude.

INTRODUCTION: Inhaled nitric oxide (INO) is a selective pulmonary vasodilator delivered from compressed gas cylinders filled to 2,200 psig (137.8 bar) with 800 ppm of NO in a balance of nitrogen. NO is currently FDA-approved for use in term or near-term infants with hypoxemia and signs of pulmonary hypertension in the absence of cardiac disease. INO has also been shown to improve oxygenation in adults with refractory hypoxemia. Current doctrine precludes the use of NO during military aeromedical transport owing to the requirement for large compressed gas cylinders. We performed a bench evaluation of 2 delivery systems that create NO from room air without the need for pressurized cylinders. MATERIALS AND METHODS: We evaluated 2 portable nitric oxide INO generation systems (LungFit PH, Beyond Air Inc, Garden City, NJ and a prototype NO generator, Odic Inc, Littleton, MA) at ground level, 8,000, and 14,000 feet (2,437 and 4,267 meter) simulated altitude in an altitude chamber. The output from each device was injected into the inspiratory limb of the ventilator circuit that was attached to a test lung. A 731 ventilator (Zoll Medical, Chelmsford, MA) and T1 (Hamilton Medical, Reno, NV) were used employing 24 combinations of ventilator settings each repeated in duplicate. An INOmax DS IR was used to measure delivered INO and NO2 via a sampling line attached in the ventilator circuit inspiratory limb. A fast response oxygen analyzer (O2CAP, Oxigraf Inc, Sunnyvale, CA) was used to measure inspired FiO2. Target INO concentration was 20 ppm. RESULTS: Across all ventilator settings, the LungFit device delivered INO was 19.8 ± 1.6 ppm, 16.1 ± 1.9 ppm, and 11.6 ± 1.7 ppm at ground level, 8,000 ft (2,437 meter), and 14,000 ft (4,267 meter), respectively. The Odic device delivered INO dose was 20.6 ± 1.4 ppm, 21.3 ± 5.5 ppm, and 20.4 ± 9.1 ppm at ground level, 8,000 ft (2,437 meter), and 14,000 ft (4,267 meter), respectively. CONCLUSIONS: Both devices delivered a reliable INO dose at ground level. Altitude significantly affected INO delivery accuracy at 14,000 ft (4,267 meter) (P < 0.01) with both devices and at 8,000 ft (2,437 meter) (P < 0.01) with LungFit. Differences in INO dosage were not statistically significant with the Odic device at 8,000 ft (2,437 meter)(P > 0.05) although there were large variations with selected ventilator settings. With careful monitoring, devices creating INO from room air without cylinders could be used during aeromedical transport without the need for pressurized cylinders.