AARC Clinical Practice Guideline: Spontaneous Breathing Trials for Liberation From Adult Mechanical Ventilation

Despite prior publications of clinical practice guidelines related to ventilator liberation, some questions remain unanswered. Many of these questions relate to the details of bedside implementation. We, therefore, formed a guidelines committee of individuals with experience and knowledge of ventilator liberation as well as a medical librarian. Using Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methodology, we make the following recommendations: (1) We suggest that calculation of a rapid shallow breathing index is not needed to determine readiness for a spontaneous breathing trial (SBT) (conditional recommendation; moderate certainty); (2) We suggest that SBTs can be conducted with or without pressure support ventilation (conditional recommendation, moderate certainty); (3) We suggest a standardized approach to assessment and, if appropriate, completion of an SBT before noon each day (conditional recommendation, very low certainty); and (4) We suggest that FIO2 should not be increased during an SBT (conditional recommendation, very low certainty). These recommendations are intended to assist bedside clinicians to liberate adult critically ill patients more rapidly from mechanical ventilation.

How to Write an Effective Discussion

Explaining the meaning of the results to the reader is the purpose of the discussion section of a research paper. There are elements of the discussion section that should be included and pitfalls that should be avoided. Always write the discussion section for the reader. Remember that the focus is to help the reader understand the study and that the focus should be on the study data.

Observational Studies

Studies can be observational or experimental. With an observational study, the investigator does not determine the assignment of subjects, and there might not be a control group. If there is a control group, assignment of the independent variable (exposure or intervention) is not under the control of the investigator. Observational studies can be rigorously conducted, but the lack of random assignment of the exposure/intervention introduces confounding and bias. Thus, the quality of evidence resulting from observational studies is lower than that of experimental randomized controlled trials (RCTs). An observational study might be performed if an RCT is unethical, impractical, or outside the control of the investigator. There are many types of prospective and retrospective observational study designs. However, an observational study design should be avoided if an experimental study is possible. Sophisticated statistical approaches can be used, but this does not elevate an observational study to the level of an RCT. Regardless of quality, an observational study cannot establish causality.

Analysis of shared cognitive tasks in the application of non-invasive ventilation to patients with COPD exacerbation

Interprofessional teamwork plays a key role in the uptake of evidence-based interventions, such as noninvasive ventilation (NIV) for patients with exacerbated Chronic Obstructive Pulmonary Disease (COPD). We aimed to identify the shared cognitive tasks in interprofessional teams using NIV for patients with COPD exacerbation. We used a cognitive task analysis approach (CTA) to engage nurses, rapid response team members, respiratory therapists, and physicians involved in the use of NIV to treat patients with COPD exacerbation. Clinicians participated in a semi-structured interview (n = 21) that elicited cognitions needed to treat COPD exacerbation. Three shared cognitive tasks were identified: Complete a thorough assessment, Formulate a care plan, and Continuously monitor patient status. Findings attest to the importance of having access to up-to-date information and expertise necessary to make accurate clinical inferences for patient assessment. Shared understanding of the formulated care plan among all members of the care team was important to its execution. Continuous monitoring was crucial; however, this cognitive task relied on patient assessment skills and ongoing collaboration within the clinical care team. Application of NIV for patients with COPD exacerbation may require enhancing collaboration through nontechnical skills and interprofessional training.

Respiratory Care Management of COPD Exacerbations

A COPD exacerbation is characterized by an increase in symptoms such as dyspnea, cough, and sputum production that worsens over a period of 2 weeks. Exacerbations are common. Respiratory therapists and physicians in an acute care setting often treat these patients. Targeted O₂ therapy improves outcomes and should be titrated to an S_pO2 of 88-92%. Arterial blood gases remain the standard approach to assessing gas exchange in patients with COPD exacerbation. The limitations of arterial blood gas surrogates (pulse oximetry, capnography, transcutaneous monitoring, peripheral venous blood gases) should be appreciated so that they can be used wisely. Inhaled short-acting bronchodilators can be provided by nebulizer (jet or mesh), pressurized metered-dose inhaler (pMDI), pMDI with spacer or valved holding chamber, soft mist inhaler, or dry powder inhaler. The available evidence for the use of heliox for COPD exacerbation is weak. Noninvasive ventilation (NIV) is standard therapy for patients who present with COPD exacerbation and is supported by clinical practice guidelines. Robust high-level evidence with patient important outcomes is lacking for the use of high-flow nasal cannula in patients with COPD exacerbation. Management of auto-PEEP is the priority in mechanically ventilated patients with COPD. This is achieved by reducing airway resistance and decreasing minute ventilation. Trigger asynchrony and cycle asynchrony are addressed to improve patient-ventilator interaction. Patients with COPD should be extubated to NIV. Additional high-level evidence is needed before widespread use of extracorporeal CO₂ removal. Care coordination can improve the effectiveness of care for patients with COPD exacerbation. Evidence-based practices improve outcomes in patients with COPD exacerbation.

Research and Publication in Respiratory Care

The evidence that informs respiratory care practice arises from research that generates facts based on the scientific method. A simple definition of research is that it is a method for finding answers to questions. The Common Rule establishes guidelines related to human subjects research, but there are many types of research not subject to the Common Rule. Although conducting research can elevate the stature of investigators, more importantly, it is an essential attribute of a profession to generate research to support clinical practice.

Exploring the Patient Experience with Noninvasive Ventilation: A Human-Centered Design Analysis to Inform Planning for Better Tolerance

BACKGROUND

This study brings a human-centered design (HCD) perspective to understanding the patient experience when using noninvasive ventilation (NIV) with the goal of creating better strategies to improve NIV comfort and tolerance.

METHODS

Using an HCD motivational approach, we created a semi-structured interview to uncover the patients' journey while being treated with NIV. We interviewed 16 patients with chronic obstructive pulmonary disease (COPD) treated with NIV while hospitalized. Patients' experiences were captured in a stepwise narrative creating a journey map as a framework describing the overall experience and highlighting the key processes, tensions, and flows. We broke the journey into phases, steps, emotions, and themes to get a clear picture of the overall experience levers for patients.

RESULTS

The following themes promoted NIV tolerance: trust in the providers, the favorable impression of the facility and staff, understanding why the mask was needed, how NIV works and how long it will be needed, immediate relief of the threatening suffocating sensation, familiarity with similar treatments, use of meditation and mindfulness, and the realization that treatment was useful. The following themes deterred NIV tolerance: physical and psychological discomfort with the mask, impaired control, feeling of loss of control, and being misinformed.

CONCLUSIONS

Understanding the reality of patients with COPD treated with NIV will help refine strategies that can improve their experience and tolerance with NIV. Future research should test ideas with the best potential and generate prototypes and design iterations to be tested with patients.

Noninvasive respiratory support for COVID-19 patients: when, for whom, and how?

The significant mortality rate and prolonged ventilator days associated with invasive mechanical ventilation (IMV) in patients with severe COVID-19 have incited a debate surrounding the use of noninvasive respiratory support (NIRS) (i.e., HFNC, CPAP, NIV) as a potential treatment strategy. Central to this debate is the role of NIRS in preventing intubation in patients with mild respiratory disease and the potential beneficial effects on both patient outcome and resource utilization. However, there remains valid concern that use of NIRS may prolong time to intubation and lung protective ventilation in patients with more advanced disease, thereby worsening respiratory mechanics via self-inflicted lung injury. In addition, the risk of aerosolization with the use of NIRS has the potential to increase healthcare worker (HCW) exposure to the virus. We review the existing literature with a focus on rationale, patient selection and outcomes associated with the use of NIRS in COVID-19 and prior pandemics, as well as in patients with acute respiratory failure due to different etiologies (i.e., COPD, cardiogenic pulmonary edema, etc.) to understand the potential role of NIRS in COVID-19 patients. Based on this analysis we suggest an algorithm for NIRS in COVID-19 patients which includes indications and contraindications for use, monitoring recommendations, systems-based practices to reduce HCW exposure, and predictors of NIRS failure. We also discuss future research priorities for addressing unanswered questions regarding NIRS use in COVID-19 with the goal of improving patient outcomes.

Update to the study protocol for an implementation-effectiveness trial comparing two education strategies for improving the uptake of noninvasive ventilation in patients with severe COPD exacerbation

BACKGROUND

There is strong evidence that noninvasive ventilation (NIV) improves the outcomes of patients hospitalized with severe COPD exacerbation, and NIV is recommended as the first-line therapy for these patients. Yet, several studies have demonstrated substantial variation in NIV use across hospitals, leading to preventable morbidity and mortality. In addition, prior studies suggested that efforts to increase NIV use in COPD need to account for the complex and interdisciplinary nature of NIV delivery and the need for team coordination. Therefore, our initial project aimed to compare two educational strategies: online education (OLE) and interprofessional education (IPE), which targets complex team-based care in NIV delivery. Due to the impact of the COVID-19 pandemic on recruitment and planned intervention, we had made several changes in the study design, statistical analysis, and implementation strategies delivery as outlined in the methods.

METHODS

We originally proposed a two-arm, pragmatic, cluster, randomized hybrid implementation-effectiveness trial comparing two education strategies to improve NIV uptake in patients with severe COPD exacerbation in 20 hospitals with a low baseline rate of NIV use. Due to logistical constrains and slow recruitment, we changed the study design to an opened cohort stepped-wedge design with three steps which will allow the institutions to enroll when they are ready to participate. Only the IPE strategy will be implemented, and the education will be provided in an online virtual format. Our primary outcome will be the hospital-level risk-standardized NIV proportion for the period post-IPE training, along with the change in rate from the period prior to training. Aim 1 will compare the change over time of NIV use among patients with COPD in the step-wedged design. Aim 2 will explore the mediators' role (respiratory therapist autonomy and team functionality) on the relationship between the implementation strategies and effectiveness. Finally, in Aim 3, through interviews with providers, we will assess the acceptability and feasibility of the educational training.

CONCLUSION

The changes in study design will result in several limitation. Most importantly, the hospitals in the three cohorts are not randomized as they enroll based on their readiness. Second, the delivery of the IPE is virtual, and it is not known if remote education is conducive to team building. However, this study will be among the first to test the impact of IPE in the inpatient setting carefully and may generalize to other interventions directed to seriously ill patients.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04206735 . Registered on December 20, 2019.

Optimal Noninvasive Medicare Access Promotion: Patients with Thoracic Restrictive Diseases A Technical Expert Panel Report from the American College of Chest Physicians, the American Association for Respiratory Care, the American Academy of Sleep Medicine, and the American Thoracic Society

The existing coverage criteria for Non-Invasive Ventilation (NIV) do not recognize the benefits of early initiation of NIV for those with Thoracic Restrictive Disease (TRD) and do not address the unique needs for daytime support as the patient's progress to ventilator dependence. This document summarizes the work of the Thoracic Restrictive Disease Technical Expert Panel working group. The most pressing current coverage barriers identified were: 1) Delays in implementing NIV treatment 2) Lack of coverage for many non-progressive Neuro-Muscular Disease (NMD) and 3) Lack of clear policy indications for Home -Mechanical Ventilation (HMV) Support in TRD. To best address these issues we make the following key recommendations: 1) Given the need to encourage early initiation of NIV with Bi-level Positive Airway Pressure (BPAP) devices, we recommend that symptoms be considered as a reason to initiate therapy even at mildly reduced FVC's.; 2) Broaden CO2 measurements to include surrogates such as transcutaneous, end-tidal or Venous Blood Gas (VBG); 3) Expand the diagnostic category to include Phrenic Nerve injuries and Disorders of Central Drive; 4) Allow a BPAP device to be advanced to an HMV when the VC is <30% or to address severe daytime respiratory symptoms; 5) Provide an additional HMV when the patient is ventilator dependent with use >18 hours/ day. Adoption of these proposed recommendations would result in the right device, at the right time, for the right type of patients with hypoventilation syndromes.

Evidence-Based Respiratory Care

Evidence-based medicine is the integration of individual clinical expertise with the best available research and the patient's values and expectations. The efficient approach to finding the best evidence is to identify systematic reviews or evidence-based clinical practice guidelines. Respiratory therapies that are supported by evidence include lung-protective ventilation and noninvasive ventilation for individuals with COPD. Evidence does not support postoperative incentive spirometry or intermittent mandatory ventilation. The principles of evidence-based medicine are a valuable approach to respiratory care practice.

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 Pa_CO2 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.

A phase I trial of low-dose inhaled carbon monoxide in sepsis-induced ARDS

BACKGROUND

Acute respiratory distress syndrome (ARDS) is a prevalent disease with significant mortality for which no effective pharmacologic therapy exists. Low-dose inhaled carbon monoxide (iCO) confers cytoprotection in preclinical models of sepsis and ARDS.

METHODS

We conducted a phase I dose escalation trial to assess feasibility and safety of low-dose iCO administration in patients with sepsis-induced ARDS. Twelve participants were randomized to iCO or placebo air 2:1 in two cohorts. Four subjects each were administered iCO (100 ppm in cohort 1 or 200 ppm in cohort 2) or placebo for 90 minutes for up to 5 consecutive days. Primary outcomes included the incidence of carboxyhemoglobin (COHb) level ≥10%, prespecified administration-associated adverse events (AEs), and severe adverse events (SAEs). Secondary endpoints included the accuracy of the Coburn-Forster-Kane (CFK) equation to predict COHb levels, biomarker levels, and clinical outcomes.

RESULTS

No participants exceeded a COHb level of 10%, and there were no administration-associated AEs or study-related SAEs. CO-treated participants had a significant increase in COHb (3.48% ± 0.7% [cohort 1]; 4.9% ± 0.28% [cohort 2]) compared with placebo-treated subjects (1.97% ± 0.39%). The CFK equation was highly accurate at predicting COHb levels, particularly in cohort 2 (R2 = 0.9205; P < 0.0001). Circulating mitochondrial DNA levels were reduced in iCO-treated participants compared with placebo-treated subjects.

CONCLUSION

Precise administration of low-dose iCO is feasible, well-tolerated, and appears to be safe in patients with sepsis-induced ARDS. Excellent agreement between predicted and observed COHb should ensure that COHb levels remain in the target range during future efficacy trials.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02425579.

FUNDING

NIH grants P01HL108801, KL2TR002385, K08HL130557, and K08GM102695.

Aerosol Delivery Devices for Obstructive Lung Diseases

Drug delivery by inhalation is the principal strategy to treat obstructive lung diseases, which affect about 15% of the population in the United States. Aerosol delivery devices have evolved over more than 60 years from the basic pressurized metered-dose inhaler and nebulizer to numerous types of inhalers and devices, including valved holder chambers, dry powder inhalers, soft mist inhalers, as well as smart inhalers and nebulizers. Although these devices improve a patient's ability to self-administer medication, many problems with optimal delivery still exist. Appropriate selection and repeated patient education can help lessen the problems with these devices. Aerosol science is evolving, with methods of measurement that include radio-scintigraphy and magnetic resonance imaging, to provide a better understanding of aerosol delivery and effects. Understanding the science and clinical application of aerosol drug delivery can substantially aid clinicians in optimizing these therapies for their patients.

Clinical Effectiveness of Incentive Spirometry for the Prevention of Postoperative Pulmonary Complications

Incentive spirometry (IS) is commonly prescribed to reduce pulmonary complications, despite limited evidence to support its benefits and a lack of consensus on optimal protocols for its use. Although numerous studies and meta-analyses have examined the effects of IS on patient outcomes, there is no clear evidence establishing its benefit to prevent postoperative pulmonary complications. Clinical practice guidelines advise against the routine use of IS in postoperative care. Until evidence of benefit from well-designed clinical trials becomes available, the routine use of IS in postoperative care is not supported by high levels of evidence.

Cost and Utility of Microbiological Cultures Early After Intensive Care Unit Admission for Intracerebral Hemorrhage

BACKGROUND

Fever is common among intensive care unit (ICU) patients. Clinicians may use microbiological cultures to differentiate infectious and aseptic fever. However, their utility depends on the prevalence of infection; and false-positive results might adversely affect patient care. We sought to quantify the cost and utility of microbiological cultures in a cohort of ICU patients with spontaneous intracerebral hemorrhage (ICH).

METHODS

We performed a secondary analysis of a cohort with spontaneous ICH requiring mechanical ventilation. We collected baseline data, measures of systemic inflammation, microbiological culture results for the first 48 h, and daily antibiotic usage. Two physicians adjudicated true-positive and false-positive culture results using standard criteria. We calculated the cost per true-positive result and used logistic regression to test the association between false-positive results with subsequent antibiotic exposure.

RESULTS

Overall, 697 subjects were included. A total of 233 subjects had 432 blood cultures obtained, with one true-positive (diagnostic yield 0.1 %, $22,200 per true-positive) and 11 false-positives. True-positive urine cultures (5 %) and sputum cultures (13 %) were more common but so were false-positives (6 and 17 %, respectively). In adjusted analysis, false-positive blood and sputum results were associated with increased antibiotic exposure.

CONCLUSIONS

The yield of blood cultures early after spontaneous ICH was very low. False-positive results significantly increased the odds of antibiotic exposure. Our results support limiting the use of blood cultures in the first two days after ICU admission for spontaneous ICH.

Respiratory Compromise as a New Paradigm for the Care of Vulnerable Hospitalized Patients

Acute respiratory compromise describes a deterioration in respiratory function with a high likelihood of rapid progression to respiratory failure and death. Identifying patients at risk for respiratory compromise coupled with monitoring of patients who have developed respiratory compromise might allow earlier interventions to prevent or mitigate further decompensation. The National Association for the Medical Direction of Respiratory Care (NAMDRC) organized a workshop meeting with representation from many national societies to address the unmet needs of respiratory compromise from a clinical practice perspective. Respiratory compromise may arise de novo or may complicate preexisting lung disease. The group identified distinct subsets of respiratory compromise that present similar opportunities for early detection and useful intervention to prevent respiratory failure. The subtypes were characterized by the pathophysiological mechanisms they had in common: impaired control of breathing, impaired airway protection, parenchymal lung disease, increased airway resistance, hydrostatic pulmonary edema, and right-ventricular failure. Classification of acutely ill respiratory patients into one or more of these categories may help in selecting the screening and monitoring strategies that are most appropriate for the patient's particular pathophysiology. Standardized screening and monitoring practices for patients with similar mechanisms of deterioration may enhance the ability to predict respiratory failure early and prevent its occurrence.

A Comparative Analysis of Pulmonary and Critical Care Medicine Guideline Development Methodologies

RATIONALE

The Institute of Medicine (IOM) standards for guideline development have had unintended negative consequences. A more efficient approach is desirable.

OBJECTIVES

To determine whether a modified Delphi process early during guideline development discriminates recommendations that should be informed by a systematic review from those that can be based upon expert consensus.

METHODS

The same questions addressed by IOM-compliant pulmonary or critical care guidelines were addressed by expert panels using a modified Delphi process, termed the Convergence of Opinion on Recommendations and Evidence (CORE) process. The resulting recommendations were compared. Concordance of the course of action, strength of recommendation, and quality of evidence, as well as the duration of recommendation development, were measured.

MEASUREMENTS AND MAIN RESULTS

When 50% agreement was required to make a recommendation, all questions yielded recommendations, and the recommended courses of action were 89.6% concordant. When 70% agreement was required, 17.9% of questions did not yield recommendations, but for those that did, the recommended courses of action were 98.2% concordant. The time to completion was shorter for the CORE process (median, 19.3 vs. 1,309.0 d; P = 0.0002).

CONCLUSIONS

We propose the CORE process as an early step in guideline creation. Questions for which 70% agreement on a recommendation cannot be achieved should go through an IOM-compliant process; however, questions for which 70% agreement on a recommendation can be achieved can be accepted, avoiding a lengthy systematic review.

Inhaled Carbon Monoxide: From Toxin to Therapy

Carbon monoxide (CO) is usually recognized as a toxic gas that can be used to assess lung function in the pulmonary function laboratory. The toxicity of CO relates to its high affinity for hemoglobin and other heme molecules, producing carboxyhemoglobin (HbCO). Despite that blood HbCO levels are commonly measured in patients with CO poisoning, the clinical presentation often does not correlate with the HbCO level, and clinical improvement in the patient's condition does not correlate with HbCO clearance. In patients with CO poisoning, administration of 100% O₂ is standard practice. If available, hyperbaric O₂ can be used, although this is controversial. Measurement of exhaled CO might be useful to estimate HbCO, such as in smoking cessation programs, but assessment of HbCO using pulse oximetry can be misleading. Endogenous CO is generated as the result of heme oxygenase activity. It is becoming increasingly recognized that the results of heme oxygenase activity, specifically CO production, might have important physiologic functions. These include effects on vascular function, inflammation, apoptosis, cell proliferation, and signaling pathways. Given the abundance of basic science supporting a therapeutic role for CO, clinical trials are exploring this potential.

Update in Management of Severe Hypoxemic Respiratory Failure

Mortality related to severe-moderate and severe ARDS remains high. We searched the literature to update this topic. We defined severe hypoxemic respiratory failure as Pao₂/Fio₂ < 150 mm Hg (ie, severe-moderate and severe ARDS). For these patients, we support setting the ventilator to a tidal volume of 4 to 8 mL/kg predicted body weight (PBW), with plateau pressure (Pplat) ≤ 30 cm H₂O, and initial positive end-expiratory pressure (PEEP) of 10 to 12 cm H₂O. To promote alveolar recruitment, we propose increasing PEEP in increments of 2 to 3 cm provided that Pplat remains ≤ 30 cm H₂O and driving pressure does not increase. A fluid-restricted strategy is recommended, and nonrespiratory causes of hypoxemia should be considered. For patients who remain hypoxemic after PEEP optimization, neuromuscular blockade and prone positioning should be considered. Profound refractory hypoxemia (Pao₂/Fio₂ < 80 mm Hg) after PEEP titration is an indication to consider extracorporeal life support. This may necessitate early transfer to a center with expertise in these techniques. Inhaled vasodilators and nontraditional ventilator modes may improve oxygenation, but evidence for improved outcomes is weak.

High-flow oxygen therapy and other inhaled therapies in intensive care units

In this Series paper, we review the current evidence for the use of high-flow oxygen therapy, inhaled gases, and aerosols in the care of critically ill patients. The available evidence supports the use of high-flow nasal cannulae for selected patients with acute hypoxaemic respiratory failure. Heliox might prevent intubation or improve gas flow in mechanically ventilated patients with severe asthma. Additionally, it might improve the delivery of aerosolised bronchodilators in obstructive lung disease in general. Inhaled nitric oxide might improve outcomes in a subset of patients with postoperative pulmonary hypertension who had cardiac surgery; however, it has not been shown to provide long-term benefit in patients with acute respiratory distress syndrome (ARDS). Inhaled prostacyclins, similar to inhaled nitric oxide, are not recommended for routine use in patients with ARDS, but can be used to improve oxygenation in patients who are not adequately stabilised with traditional therapies. Aerosolised bronchodilators are useful in mechanically ventilated patients with asthma and chronic obstructive pulmonary disease, but are not recommended for those with ARDS. Use of aerosolised antibiotics for ventilator-associated pneumonia and ventilator-associated tracheobronchitis shows promise, but the delivered dose can be highly variable if proper attention is not paid to the delivery method.

Aerosol Therapy During Noninvasive Ventilation or High-Flow Nasal Cannula

Noninvasive ventilation (NIV) and high-flow nasal cannula (HFNC) are increasingly used for patients with acute respiratory failure. Some patients receiving these therapies might also benefit from inhaled drug delivery. Thus, it is attractive to combine aerosol therapy with NIV or HFNC. The purpose of this paper is to review the available evidence related to the use of inhaled aerosols with NIV or HFNC. Available evidence supports the delivery of aerosols during NIV. Inhaled bronchodilator response might be improved with the use of NIV in acute asthma, but the evidence is not sufficiently mature to recommend this as standard therapy. Evidence does support aerosol delivery without discontinuation of NIV. Clinical studies on aerosol delivery during HFNC are needed, and based on the available in vitro evidence, it is not possible to make a recommendation for or against aerosol delivery during HFNC.

Regional Ventilation and Aerosol Deposition with Helium-Oxygen in Bronchoconstricted Asthmatic Lungs

BACKGROUND

Theoretical models suggest that He-O2 as carrier gas may lead to more homogeneous ventilation and aerosol deposition than air. However, these effects have not been clinically consistent and it is unclear why subjects may or may not respond to the therapy. Here we present 3D-imaging data of aerosol deposition and ventilation distributions from subjects with asthma inhaling He-O2 as carrier gas. The data are compared with those that we previously obtained from a similar group of subjects inhaling air.

METHODS

Subjects with mild-to-moderate asthma were bronchoconstricted with methacholine and imaged with PET-CT while inhaling aerosol carried with He-O2. Mean-normalized-values of lobar specific ventilation sV* and deposition sD* were derived and the factors affecting the distribution of sD* were evaluated along with the effects of breathing frequency (f) and regional expansion (FVOL).

RESULTS

Lobar distributions of sD* and sV* with He-O2 were not statistically different from those previously measured with air. However, with He-O2 there was a larger number of lobes having sV* and sD* closer to unity and, in those subjects with uneven deposition distributions, the correlation of sD* with sV* was on average higher (p < 0.05) in He-O2 (0.84 ± 0.8) compared with air (0.55 ± 0.28). In contrast with air, where the frequency of breathing during nebulization was associated with the degree of sD*-sV* correlation, with He-O2 there was no association. Also, the modulation of f on the correlation between FVOL and sD*/sV* in air, was not observed in He-O2.

CONCLUSION

There were no differences in the inter-lobar heterogeneity of sD* or sV* in this group of mild asthmatic subjects breathing He-O2 compared with patients previously breathing air. Future studies, using these personalized 3D data sets as input to CFD models, are needed to understand if, and for whom, breathing He-O2 during aerosol inhalation may be beneficial.

The Regulation of Proresolving Lipid Mediator Profiles in Baboon Pneumonia by Inhaled Carbon Monoxide

Strategies for the treatment of bacterial pneumonia beyond traditional antimicrobial therapy have been limited. The recently discovered novel genus of lipid mediators, coined "specialized proresolving mediators" (SPMs), which orchestrate clearance of recruited leukocytes and restore epithelial barrier integrity, have offered new insight into the resolution of inflammation. We performed lipid mediator (LM) metabololipidomic profiling and identification of LMs on peripheral blood leukocytes and plasma from a baboon model of Streptococcus pneumoniae pneumonia. Leukocytes and plasma were isolated from whole blood of S. pneumoniae-infected (n = 5-6 per time point) and control, uninfected baboons (n = 4 per time point) at 0, 24, 48, and 168 hours. In a subset of baboons with pneumonia (n = 3), we administered inhaled carbon monoxide (CO) at 48 hours (200-300 ppm for 60-90 min). Unstimulated leukocytes from control animals produced a proresolving LM signature with elevated resolvins and lipoxins. In contrast, serum-treated, zymosan-stimulated leukocytes and leukocytes from baboons with S. pneumoniae pneumonia produced a proinflammatory LM signature profile with elevated leukotriene B4 and prostaglandins. Plasma from baboons with S. pneumoniae pneumonia also displayed significantly reduced LM-SPM levels, including eicosapentaenoic acid-derived E-series resolvins (RvE) and lipoxins. CO inhalation increased levels of plasma RvE and lipoxins relative to preexposure levels. These results establish the leukocyte and plasma LM profiles biosynthesized during S. pneumoniae pneumonia in baboons and provide evidence for pneumonia-induced dysregulation of these proresolution programs. Moreover, these SPM profiles are partially restored with inhaled low-dose CO and SPM, which may shorten the time to pneumonia resolution.

Recruitment Maneuvers and PEEP Titration

The injurious effects of alveolar overdistention are well accepted, and there is little debate regarding the importance of pressure and volume limitation during mechanical ventilation. The role of recruitment maneuvers is more controversial. Alveolar recruitment is desirable if it can be achieved, but the potential for recruitment is variable among patients with ARDS. A stepwise recruitment maneuver, similar to an incremental PEEP titration, is favored over sustained inflation recruitment maneuvers. Many approaches to PEEP titration have been proposed, and the best method to choose the most appropriate level for an individual patient is unclear. A PEEP level should be selected that balances alveolar recruitment against overdistention. The easiest approach to select PEEP might be according to the severity of the disease: 5-10 cm H2O PEEP in mild ARDS, 10-15 cm H2O PEEP in moderate ARDS, and 15-20 cm H2O PEEP in severe ARDS. Recruitment maneuvers and PEEP should be used within the context of lung protection and not just as a means of improving oxygenation.

Effects of inhaled CO administration on acute lung injury in baboons with pneumococcal pneumonia

Inhaled carbon monoxide (CO) gas has therapeutic potential for patients with acute respiratory distress syndrome if a safe, evidence-based dosing strategy and a ventilator-compatible CO delivery system can be developed. In this study, we used a clinically relevant baboon model of Streptococcus pneumoniae pneumonia to 1) test a novel, ventilator-compatible CO delivery system; 2) establish a safe and effective CO dosing regimen; and 3) investigate the local and systemic effects of CO therapy on inflammation and acute lung injury (ALI). Animals were inoculated with S. pneumoniae (10(8)-10(9) CFU) (n = 14) or saline vehicle (n = 5); in a subset with pneumonia (n = 5), we administered low-dose, inhaled CO gas (100-300 ppm × 60-90 min) at 0, 6, 24, and/or 48 h postinoculation and serially measured blood carboxyhemoglobin (COHb) levels. We found that CO inhalation at 200 ppm for 60 min is well tolerated and achieves a COHb of 6-8% with ambient CO levels ≤ 1 ppm. The COHb level measured at 20 min predicted the 60-min COHb level by the Coburn-Forster-Kane equation with high accuracy. Animals given inhaled CO + antibiotics displayed significantly less ALI at 8 days postinoculation compared with antibiotics alone. Inhaled CO was associated with activation of mitochondrial biogenesis in the lung and with augmentation of renal antioxidative programs. These data support the feasibility of safely delivering inhaled CO gas during mechanical ventilation and provide preliminary evidence that CO may accelerate the resolution of ALI in a clinically relevant nonhuman primate pneumonia model.

Year in Review 2014: Patient Safety

The topic of patient safety has received much attention in recent years. There are a number of areas in which the subject of patient safety impacts respiratory care practice. This paper focuses on articles published in 2014 related to pressure injury, handoffs, protocols and multidisciplinary teams, perioperative obstructive sleep apnea, and readmissions.

Respiratory care year in review 2013: neonatal respiratory care, pulmonary function testing, and pulmonary rehabilitation

Respiratory care practice includes neonatal respiratory care, pulmonary function testing, and pulmonary rehabilitation. The purpose of this paper is to review the recent literature related to these topics in a manner that is most likely to have interest to the readers of Respiratory Care.

Developing a New, National Approach to Surveillance for Ventilator-Associated Events: Executive Summary

This article is an executive summary of a report from the Centers for Disease Control and Prevention Ventilator-Associated Pneumonia Surveillance Definition Working Group, entitled “Developing a new, national approach to surveillance for ventilator-associated events” and published in Critical Care Medicine. The full report provides a comprehensive description of the Working Group process and outcome.

In September 2011, the Centers for Disease Control and Prevention (CDC) convened a Ventilator-Associated Pneumonia (VAP) Surveillance Definition Working Group to organize a formal process for leaders and experts of key stakeholder organizations to discuss the challenges of VAP surveillance definitions and to propose new approaches to VAP surveillance in adult patients (Table 1).

Respiratory care year in review 2012: Asthma and sleep-disordered breathing

Asthma has long been recognized as a common respiratory disease, and the recognition of sleep-disordered breathing is becoming more prevalent. Patients with these disorders are commonly seen by clinicians caring for patients with respiratory disease. There is also much academic interest in asthma and sleep-disordered breathing. The purpose of this paper is to review the recent literature related to asthma and sleep-disordered breathing in a manner that is most likely to have interest to the readers of Respiratory Care.

Noninvasive ventilation for acute respiratory failure

Noninvasive ventilation (NIV) for acute respiratory failure has gained much academic and clinical interest. Despite this, NIV is underutilized. The evidence strongly supports its use in patients presenting with an exacerbation of COPD and in patients with acute cardiogenic pulmonary edema. As reviewed in this paper, there is now evidence supporting or not supporting the use of NIV in various other presentations of acute respiratory failure. It is important not only to know when to initiate NIV, but also when this therapy is failing. Whether NIV in the setting of acute respiratory failure can be managed appropriately outside the ICU setting is controversial. Although a variety of interfaces are available, the oronasal mask is the best initial interface in terms of leak prevention and patient comfort. Some critical care ventilators have NIV modes that compensate well for leaks, but as a group the ventilators that are designed specifically for NIV have better leak compensation. NIV should be part of the armamentarium of all clinicians caring from patients with acute respiratory failure.

Respiratory Care year in review 2012: invasive mechanical ventilation, noninvasive ventilation, and cystic fibrosis

For the busy clinician, educator, or manager, it is becoming an increasing challenge to filter the literature to what is relevant to one's practice and then update one's practice based on the current evidence. The purpose of this paper is to review the recent literature related to invasive mechanical ventilation, noninvasive ventilation, and cystic fibrosis. These topics were chosen and reviewed in a manner that is most likely to have interest to the readers of Respiratory Care.

Respiratory therapy organizational changes are associated with increased respiratory care utilization

BACKGROUND

The effect of the respiratory therapist (RT)/patient ratio and RT organizational factors on respiratory resource utilization is unknown. We describe the impact of a multi-component intervention that called for an increase in RT/patient ratio (1:14 to 1:10), improved RT orientation, and formation of a core staffing model on best practice, including spontaneous breathing trials (SBTs) and catheter and bronchoscopically directed lower respiratory tract cultures, or bronchoalveolar lavage (BAL), in both ventilated and non-ventilated patients in the ICU.

METHODS

We conducted a single center, quasi-experimental study comparing 651 patients with single and first admissions between April 19, 2005 and April 18, 2006 before the RT services reorganization with 1,073 patients with single and first admissions between September 16, 2007 and September 4, 2008. Baseline characteristics were compared, along with SBTs, BAL use, lower respiratory tract cultures, and chest physiotherapy.

RESULTS

Patients in the 2 groups were similar in terms of age (52.9 ± 15.8 y vs 53.9 ± 16.4 y, P = .23), comorbidity as measured by Charlson score (2.8 ± 2.6 vs 2.8 ± 2.7, P = .56), and acuity of illness as measured by the Case Mix Index (3.2 ± 3.9 vs 3.3 ± 4.1, P = .47). Mechanically ventilated patients had similar prevalences of respiratory diseases (24.2% vs 25.1%, P = .61). There was an increase in SBTs (0.5% vs 73.1%, P < .001), chest physiotherapy (7.4% vs 21.6%, P < .001), BALs (24.0% vs 41.4%, P < .001), and lower respiratory tract cultures (21.5% vs 38.0%, P < .001) in mechanically ventilated patients post-intervention.

CONCLUSIONS

A multi-component intervention, including an increase in RT/patient ratio, improved RT orientation, and establishment of a core staffing model, was associated with increased respiratory resource utilization and evidence-based practice, specifically BALs and SBTs.

Tracheostomy tube change before day 7 is associated with earlier use of speaking valve and earlier oral intake

BACKGROUND

Presence of a tracheostomy tube often decreases the patient's ability to communicate and to tolerate oral intake. The initial tracheostomy tube change is often recommended between day 7 and 14 post insertion. Local guidelines permit tracheostomy tube change 5 days after insertion.

OBJECTIVE

We hypothesized that changing tracheostomy tubes before day 7 is associated with earlier use of a speaking valve as well as earlier oral intake, compared to changing tracheostomy tubes after 7 days.

METHODS

We prospectively enrolled 130 admitted subjects, after tracheostomy placement to a respiratory care unit between July 2008 and May 2010. Subject data were recorded from the electronic medical record. The primary end point was the time from tracheostomy tube placement to tolerating speaking valve. The secondary end point was the time from tracheostomy tube placement to tolerating oral intake. Complications of tracheostomy tube change were recorded.

RESULTS

Thirty-eight subjects had the first tracheostomy tube change before 7 days (early group), and 92 subjects had the first tracheostomy tube change after 7 days (late group). The early group tolerated a speaking valve significantly sooner than the late group (7 d vs 12 d, P = .001). The early group also tolerated oral intake significantly sooner (10 d vs 20 d, P = .04). After change of the tracheostomy tube, the time to tolerating oral feeding was 5.5 days in both groups. There was no significant difference in time to decannulation between the groups. The early group had a shorter respiratory care unit stay (11 d vs 17 d, P = .001) and a shorter hospital stay (P = .05) than the late group. There was no difference in survival. There were no complications associated with tracheostomy tube change.

CONCLUSIONS

Tracheostomy tube change before day 7 is associated with earlier ability to tolerate speaking valve and oral intake. In this series, early tracheostomy tube change was not associated with an increased rate of complications.

Developing a new, national approach to surveillance for ventilator-associated events

This article is an executive summary of a report from the Centers for Disease Control and Prevention Ventilator-Associated Pneumonia Surveillance Definition Working Group, entitled "Developing a New, National Approach to Surveillance for Ventilator-Associatied Events," published in Critical Care Medicine, by Magill SS, Klompas M, Balk R, Burns SM, Deutschman CS, et al. 2013;41(11):2467-2475. The full report provides a comprehensive description of the Working Group's process and outcome.

Examination of patterns in intubation by an emergency airway team at a large academic center: higher frequency during daytime hours

BACKGROUND

Emergency airway management represents an event with high acuity but unpredictable frequency and therefore presents a challenge for adequate staffing. Given circadian and seasonal variations, we hypothesized that the majority of emergency airway events happen after normal working hours and during the winter months.

METHODS

A retrospective analysis of 1,482 intubations by an emergency airway team over a 3-y period was performed. The data were obtained from hospitalized patients who required emergency airway management in a large academic medical center. A database of emergency airway consultations was analyzed for intubation time and date information, as well as geographic location within the hospital.

RESULTS

A greater percentage of emergency intubations occurred during day shift hours (7 am to 7 pm) compared with night shift hours, 57% and 43%, respectively (P < .01). The monthly frequency of intubations was not uniformly distributed across the year (P < .01). The greatest percentage of intubations was performed in February (10.9%), with the lowest being recorded in August (4.7%).

CONCLUSIONS

Emergency airway service utilization is highest during daytime hours, with seasonal variations composed of higher consults in the winter and lower consults in the summer.