Inertial Motion Capture-Based Whole-Body Inverse Dynamics.

Inertial Motion Capture (IMC) systems enable in situ studies of human motion free of the severe constraints imposed by Optical Motion Capture systems. Inverse dynamics can use those motions to estimate forces and moments developing within muscles and joints. We developed an inverse dynamic whole-body model that eliminates the usage of force plates (FPs) and uses motion patterns captured by an IMC system to predict the net forces and moments in 14 major joints. We validated the model by comparing its estimates of Ground Reaction Forces (GRFs) to the ground truth obtained from FPs and comparing predictions of the static model's net joint moments to those predicted by 3D Static Strength Prediction Program (3DSSPP). The relative root-mean-square error (rRMSE) in the predicted GRF was 6% and the intraclass correlation of the peak values was 0.95, where both values were averaged over the subject population. The rRMSE of the differences between our model's and 3DSSPP predictions of net L5/S1 and right and left shoulder joints moments were 9.5%, 3.3%, and 5.2%, respectively. We also compared the static and dynamic versions of the model and found that failing to account for body motions can underestimate net joint moments by 90% to 560% of the static estimates.

Evaluating Delivery of Low Tidal Volume Ventilation in Six ICUs Using Electronic Health Record Data.

OBJECTIVES: Mechanical ventilation with low tidal volumes is recommended for all patients with acute respiratory distress syndrome and may be beneficial to other intubated patients, yet consistent implementation remains difficult to obtain. Using detailed electronic health record data, we examined patterns of tidal volume administration, the effect on clinical outcomes, and alternate metrics for evaluating low tidal volume compliance in clinical practice. DESIGN: Observational cohort study. SETTING: Six ICUs in a single hospital system. PATIENTS: Adult patients who received invasive mechanical ventilation more than 12 hours. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Tidal volumes were analyzed across 1,905 hospitalizations. Although mean tidal volume was 6.8 mL/kg predicted body weight, 40% of patients were exposed to tidal volumes greater than 8 mL/kg predicted body weight, with 11% for more than 24 hours. At a patient level, exposure to 24 total hours of tidal volumes greater than 8 mL/kg predicted body weight was associated with increased mortality (odds ratio, 1.82; 95% CI, 1.20-2.78), whereas mean tidal volume exposure was not (odds ratio, 0.87/1 mL/kg increase; 95% CI, 0.74-1.02). Initial tidal volume settings strongly predicted exposure to volumes greater than 8 mL/kg for 24 hours; the adjusted rate was 21.5% when initial volumes were greater than 8 mL/kg predicted body weight and 7.1% when initial volumes were less than 8 mL/kg predicted body weight. Across ICUs, correlation of mean tidal volume with alternative measures of low tidal volume delivery ranged from 0.38 to 0.66. CONCLUSIONS: Despite low mean tidal volume in the cohort, a significant percentage of patients were exposed to a prolonged duration of high tidal volumes which was correlated with higher mortality. Detailed ventilator records in the electronic health record provide a unique window for evaluating low tidal volume delivery and targets for improvement.

Fatigue Detection Using Phase-Space Warping.

A novel application of phase-space warping (PSW) method to detect fatigue in the musculoskeletal system is presented. Experimental kinematic, force, and physiological signals are used to produce a fatigue metric. The metric is produced using time-delay embedding and PSW methods. The results showed that by using force and kinematic signals, an overall estimate of the muscle group state can be achieved. Further, when using electromyography (EMG) signals the fatigue metric can be used as a tool to evaluate muscles activation and load sharing patterns for individual muscles. The presented method will allow for fatigue evolution measurement outside a laboratory environment, which open doors to applications such as tracking the physical state of players during competition, workers in a plant, and patients undergoing in-home rehabilitation.

Ventilator discontinuation protocols.

Mechanical ventilation is a life-saving supportive therapy, but it can also cause lung injury, diaphragmatic dysfunction, and lung infection. Ventilator liberation should be attempted as soon as clinically indicated, to minimize morbidity and mortality. The most effective method of liberation follows a systematic approach that includes a daily assessment of weaning readiness, in conjunction with interruption of sedation infusions and spontaneous breathing trials. Protocols and checklists are decision support tools that help ensure consistent application of key elements of evidence-based practice. A majority of studies of weaning protocols applied by non-physician healthcare providers suggest faster weaning and shorter duration of ventilation and ICU stay, and some suggest reduced failed extubation and ventilator-associated pneumonia rates. Checklists can be used to reinforce application of the protocol, or possibly in lieu of one, particularly in environments where the caregiver-to-patient ratio is high and clinicians are well versed in and dedicated to applying evidence-based care. There is support for integrating best-evidence rules for weaning into the mechanical ventilator so that a substantial portion of the weaning process can be automated, which may be most effective in environments with low caregiver-to-patient ratios or those in which it is challenging to consistently apply evidence-based care. This paper reviews evidence for ventilator liberation protocols and discusses issues of implementation and ongoing monitoring.

Respiratory care year in review 2011: long-term oxygen therapy, pulmonary rehabilitation, airway management, acute lung injury, education, and management.

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 long-term oxygen therapy, pulmonary rehabilitation, airway management, acute lung injury and acute respiratory distress syndrome, respiratory care education, and respiratory care management. These topics were chosen and reviewed in a manner that is most likely to have interest to the readers of Respiratory Care.

Advanced ventilator modes and techniques.

In addition to improving gas exchange by mechanical ventilation, minimizing iatrogenic lung injury and making the patient comfortable are important goals. This article reviews advanced ventilator modes and techniques that might help to accomplish these goals. Small tidal volumes (VT) and low ventilation pressure minimize ventilator-induced lung injury. Airway pressure release ventilation and high-frequency oscillatory ventilation may provide lung-protective ventilation in certain patients with refractory hypoxemia. Adaptive support ventilation (ASV) automatically adjusts VT and rate on the basis of the patient's respiratory mechanics to provide "safe" settings. When ventilator output does not match patient respiratory center timing, patient-ventilator asynchrony occurs. Proportional assist ventilation and neutrally adjusted ventilatory assist are unique modes of ventilation that provide ventilatory support in direct proportion to patient effort and therefore may be able to better match patient need and improve comfort. Weaning protocols reduce duration of ventilation and intensive care unit stay. Certain ventilator modes purport to automate part of the ventilator discontinuance process. The ASV progressively reduces support as the patient's lung condition improves, while SmartCare/pressure support (Dräger, Lübeck, Germany) reduces support and then initiates a spontaneous breathing trial. Further research is required to determine the proper place these new modes have in the intensive care unit.

Automated notification of suspected obstructive sleep apnea patients to the perioperative respiratory therapist: a pilot study.

BACKGROUND: Obstructive sleep apnea (OSA) increases the risk of central and obstructive apneas after anesthesia, but the vast majority of patients with OSA are undiagnosed preoperatively. Current guidelines promote the use of postoperative continuous positive airway pressure (CPAP) in patients with OSA. Owing to the complex postoperative requirements of these patients, respiratory therapists (RTs) could substantially improve these patients' clinical management in the immediate postoperative period. We describe a system that identifies patients with suspected or documented OSA and automatically alerts the perioperative RT. METHODS: Patients who presented for surgery were preoperatively assessed, and if the patient had a diagnosis of OSA or OSA risk factors, the perioperative RT automatically received a paging alert, after the surgery. The RT reviewed the patient postoperatively and instituted CPAP or bi-level positive airway pressure (BiPAP), as indicated. We collected data on triggers for the automated alerts and utilization of CPAP and BiPAP. We reviewed risk-management data to analyze the effect of this intervention on postsurgical sudden-onset acute respiratory compromise. RESULTS: Of 7,422 patients who presented for surgery over a 5-month period, 766 had an OSA diagnosis or OSA risk factors. There were an average of 7-8 alerts per work day (range 2-18 alerts per day). On average, 2 patients per day were treated with CPAP/BiPAP in the post-anesthesia care unit or the postoperative general ward as a result of the alerts. The median paging alert time was 10:30 am. There were no episodes of sudden-onset postoperative acute respiratory compromise after institution of the OSA alert system. CONCLUSIONS: As part of a hospital-wide postoperative policy, our automated OSA alert and perioperative RT system helped prevent sudden-onset acute respiratory compromise in postoperative patients with OSA or at risk of OSA.

A definition framework for building adaptation projects.

Building adaptation encompasses a range of construction activities that improve existing building conditions and extend the effective lives of buildings. The scopes of building adaptation projects vary, and may include rehabilitating failing structures, improving environmental performances, and changing functional uses. In order to address multiple aspects of building adaptation, different terminologies are used in the literature and in practice, including refurbishment, retrofitting, rehabilitation, renovation, restoration, modernization, conversion, adaptive reuse, material reuse, conservation, and preservation, amongst others. These terminologies are often used interchangeably with overlapping definitions, causing a lack of clarity in the addressed scope of work. An extensive literature review of terminologies related to building adaptation was conducted and the most common and applicable terminologies were identified. Recent definitions, applications, and scope for the identified terminologies are reviewed. Based on this classification, a definition framework is developed enabling precise categorization of building adaptation projects, and application is demonstrated in multiple case studies. The proposed definition framework is a valuable reference for future researchers and practitioners to clearly and consistently define the scope of work in their building adaption projects, and thus avoiding the high costs arising from codes, specifications, and project descriptions that confuse these definitions.

Adequacy of the Provider Workforce for Persons With Cardiopulmonary Disease.

BACKGROUND: Access and quality of health care for cardiopulmonary disease in the United States ranks poorly compared with economically similar nations. No recent comprehensive assessment of the cardiopulmonary workforce is available. This systematic review was conducted to evaluate current published evidence about the workforce caring for persons with cardiopulmonary disease. METHODS: This systematic review followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Structured searches of medical databases were conducted to find studies published from 2006 through 2016. Because of the paucity of quantitative data retrieved, a qualitative synthesis was conducted. Thematic analyses were performed on 15 identified articles through a process of open and axial coding. RESULTS: There is published evidence of current and projected workforce shortages in all clinical settings where care of persons with cardiopulmonary disease occurs. Advanced practice providers complete much of their cardiopulmonary training on the job. The aging population and the advent of new medical interventions are projected to increase growth in health-care demand. Some physicians limit hiring of advanced practice providers because of a deficiency in formal cardiopulmonary training. CONCLUSIONS: There is a gap in care between the needs of persons with cardiopulmonary disease and cardiopulmonary providers. Strategies resolving this problem may include one or more approaches that reduce the administrative burden associated with current care and assure the availability of suitably trained providers.

Training and Deployment of Medical Students as Respiratory Therapist Extenders during COVID-19.

Background: Early experience during the coronavirus disease (COVID-19) pandemic and predictive modeling indicate that the need for respiratory therapists (RTs) will exceed the current supply. Objective: We present an implemented model to train and deploy medical students in the novel role of "respiratory therapist extender" (RTE) to address respiratory therapist shortage during the COVID-19 pandemic. Methods: The RTE role was formulated through discussions with respiratory therapists. A three-part training, with both online and in-person components, was developed and delivered to 25 University of Michigan Medical Students. RTEs were trained in basic respiratory care, documentation, equipment preparation, and equipment processing for clinically stable patients. They operate in a tiered staffing model in which RTEs report to a single RT, thereby extending his/her initial capacity. Results: The first cohort of safely trained RTEs was deployed to provide patient care within 1 week of volunteer recruitment. Conclusion: Our experience has demonstrated that healthcare professionals, including medical students, can be quickly trained and deployed in the novel RTE role as a surge strategy during the COVID-19 pandemic. Because we urgently developed and implemented the RTE role, we recognize the need for ongoing monitoring and adaptation to ensure patient and volunteer safety. We are sharing the RTE concept and training openly to help address RT shortages as the pandemic evolves.

Airway clearance applications in the elderly and in patients with neurologic or neuromuscular compromise.

Respiratory compromise is the leading cause of morbidity and mortality in patients with neuromuscular and neurologic disease, and in elderly patients, who have a reduced pulmonary reserve from deterioration of the respiratory system associated with the normal aging process. Although the otherwise healthy older patient is normally asymptomatic, their pulmonary reserve is further compromised during stressful situations such as surgery, pneumonia, or exacerbation of a comorbid condition. The inability to effectively remove retained secretions and prevent aspiration contribute to this compromise. Although no secretion-management therapies are identified as having specific application to the elderly, clinicians must be attentive and understand the needs of the elderly to prevent the development of respiratory compromise. Patients with neuromuscular disease often can not generate an effective cough to mobilize and evacuate secretions. Respiratory muscle training, manual cough assistance, mechanical cough assistance, high-frequency chest wall compression, and intrapulmonary percussive ventilation have each been suggested as having potential benefit in this population. Although strong evidence supporting the benefit of these therapies is lacking, clinicians must be guided as to whether there is a pathophysiologic rationale for applying the therapy, whether adverse effects are associated with the therapy, the cost of therapy, and whether the patient prefers a given therapy.

AARC Clinical Practice Guideline: Effectiveness of Pharmacologic Airway Clearance Therapies in Hospitalized Patients.

Aerosolized medications are used as airway clearance therapy to treat a variety of airway diseases. These guidelines were developed from a systematic review with the purpose of determining whether the use of these medications to promote airway clearance improves oxygenation and respiratory mechanics, reduces ventilator time and ICU stay, and/or resolves atelectasis/consolidation compared with usual care. Recombinant human dornase alfa should not be used in hospitalized adult and pediatric patients without cystic fibrosis. The routine use of bronchodilators to aid in secretion clearance is not recommended. The routine use of aerosolized N-acetylcysteine to improve airway clearance is not recommended. Aerosolized agents to change mucus biophysical properties or promote airway clearance are not recommended for adult or pediatric patients with neuromuscular disease, respiratory muscle weakness, or impaired cough. Mucolytics are not recommended to treat atelectasis in postoperative adult or pediatric patients, and the routine administration of bronchodilators to postoperative patients is not recommended. There is no high-level evidence related to the use of bronchodilators, mucolytics, mucokinetics, and novel therapy to promote airway clearance in these populations.

Inhaled nitric oxide to improve oxygenation for safe critical care transport of adults with severe hypoxemia.

BACKGROUND: Inhaled nitric oxide (iNO) is a rescue treatment for severe hypoxemia in the intensive care unit setting. OBJECTIVE: To evaluate the effectiveness and safety of iNO in adult patients with severe hypoxemia before and during transport to a tertiary care center. METHODS: Prospective data were examined in a retrospective cohort study. Patients with severe hypoxemia and cardiopulmonary failure (n=139) at referring hospitals in whom conventional therapy was unsuccessful were treated with iNO in the intensive care units in anticipation of transfer to a tertiary center. Treatment wih iNO was initiated by the critical care transport team in 114 patients and continued in 25 patients. Arterial blood gas analysis was done before and after iNO treatment. RESULTS: Patients treated with iNO had significant improvement in oxygenation: mean (SD) for PaO2 increased from 60.7 (20.2) to 72.3 (40.6) mm Hg (P=.008), and mean (SD) for ratio of PaO2 to fraction of inspired oxygen (P:F) increased from 62.4 (26.1) to 73.1 (42.6) (P= .03). Use of iNO was continued through transport in 102 patients, all of whom were transported without complication. The P:F continued to improve, with a mean (SD) of 109.7 (73.8) from 6 to 8 hours after arrival at the tertiary center (P< .001 relative to values both before and after treatment). Among patients treated with iNO, 60.2% survived to discharge. In 35 nonresponders, iNO was discontinued, and 15 patients could not be transferred owing to life-threatening hypoxemia; 2 were later transferred on extracorporeal membrane oxygenation. Of 18 patients transported without iNO, 9 (50%) survived. CONCLUSIONS: Use of iNO significantly improves oxygenation of patients with severe hypoxemia and allows safe transfer to a tertiary care center.

Lung protective mechanical ventilation in acute respiratory distress syndrome.

The evidence supports the idea that mechanical ventilation can potentially cause further lung injury. The only ventilator manipulation that so far has been shown definitively to reduce injury and improve mortality is the reduction of VT to 6 mL/kg PBW or lower and targeting Pplat to 30 cm H2O or lower. Much research is needed to provide further guidance in applying ventilatory support techniques.

Intrahospital transport of the adult mechanically ventilated patient.

As the diagnosis and treatment of critically ill patients continues to advance, the frequency of intrahospital transport of ventilator-dependent patients increases. Once the risks and benefits of transport are established, even the sickest ICU patient can be transported safely when adequate time is taken and preparations are made before beginning the transport. Patients should be stabilized as much as possible and monitored before, during, and after transport. Those responsible for the patient should be trained to provide a safe outcome. This necessitates that caregivers receive education in patient evaluation, potential risks, complications, interventions, equipment operation, and troubleshooting that may be necessary when caring for ventilated patients outside the ICU. All members of the transport team should communicate effectively and be aware of their roles in the transport process to minimize delays and mishaps during transport and at the final destination. Written policies that define the level of personnel, level of training, level of support, and equipment necessary can facilitate the transport process. When choosing a device to provide ventilation, the patient's clinical condition should be determine which method is used for transport.

Endotracheal tubes: old and new.

The development and evolution of the endotracheal tube (ETT) have been closely related to advances in surgery and anesthesia. Modifications were made to accomplish many tasks, including minimizing gross aspiration, isolating a lung, providing a clear facial surgical field during general anesthesia, monitoring laryngeal nerve damage during surgery, preventing airway fires during laser surgery, and administering medications. In critical care management, ventilator-associated pneumonia (VAP) is a major concern, as it is associated with increased morbidity, mortality, and cost. It is increasingly appreciated that the ETT itself is a primary causative risk for developing VAP. Unfortunately, contaminated oral and gastric secretions leak down past the inflated ETT cuff into the lung. Bacteria can also grow within the ETT in biofilm and re-enter the lung. Modifications to the ETT that attempt to prevent bacteria from entering around the ETT include maintaining an adequate cuff pressure against the tracheal wall, changing the material and shape of the cuff, and aspirating the secretions that sit above the cuff. Attempts to reduce bacterial entry through the tube include antimicrobial coating of the ETT and mechanically scraping the biofilm from within the ETT. Studies evaluating the effectiveness of these modifications and techniques demonstrate mixed results, and clear recommendations for which modification should be implemented are weak.

AARC clinical practice guideline: effectiveness of nonpharmacologic airway clearance therapies in hospitalized patients.

Airway clearance therapy (ACT) is used in a variety of settings for a variety of ailments. These guidelines were developed from a systematic review with the purpose of determining whether the use of nonpharmacologic ACT improves oxygenation, reduces length of time on the ventilator, reduces stay in the ICU, resolves atelectasis/consolidation, and/or improves respiratory mechanics, versus usual care in 3 populations. For hospitalized, adult and pediatric patients without cystic fibrosis, 1) chest physiotherapy (CPT) is not recommended for the routine treatment of uncomplicated pneumonia; 2) ACT is not recommended for routine use in patients with COPD; 3) ACT may be considered in patients with COPD with symptomatic secretion retention, guided by patient preference, toleration, and effectiveness of therapy; 4) ACT is not recommended if the patient is able to mobilize secretions with cough, but instruction in effective cough technique may be useful. For adult and pediatric patients with neuromuscular disease, respiratory muscle weakness, or impaired cough, 1) cough assist techniques should be used in patients with neuromuscular disease, particularly when peak cough flow is < 270 L/min; CPT, positive expiratory pressure, intrapulmonary percussive ventilation, and high-frequency chest wall compression cannot be recommended, due to insufficient evidence. For postoperative adult and pediatric patients, 1) incentive spirometry is not recommended for routine, prophylactic use in postoperative patients, 2) early mobility and ambulation is recommended to reduce postoperative complications and promote airway clearance, 3) ACT is not recommended for routine postoperative care. The lack of available high-level evidence related to ACT should prompt the design and completion of properly designed studies to determine the appropriate role for these therapies.

Current knowledge of acute lung injury and acute respiratory distress syndrome.

Acute lung injury/acute respiratory distress syndrome (ALI/ARDS) continues to be a major cause of mortality in adult and pediatric critical care medicine. This article discusses the pulmonary sequelae associated with ALI and ARDS, the support of ARDS with mechanical ventilation, available adjunctive therapies, and experimental therapies currently being tested. It is hoped that further understanding of the fundamental biology, improved identification of the patient's inflammatory state, and application of therapies directed at multiple sites of action may ultimately prove beneficial for patients suffering from ALI/ARDS.

Mechanical ventilation with lung protective strategies: what works?

Essentially all patients with acute lung injury or acute respiratory distress syndrome require mechanical ventilatory assistance to support gas exchange and reduce the work of breathing associated with the lung impairment. Unfortunately, this life-sustaining support may actually cause further lung damage and possibly lead to increased mortality. This article reviews strategies that may help minimize ventilator-induced lung injury.