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Respiratory Care Jan 2022Mechanical ventilators display detailed waveforms which contain a wealth of clinically relevant information. Although much has been written about interpretation of...
Mechanical ventilators display detailed waveforms which contain a wealth of clinically relevant information. Although much has been written about interpretation of waveforms and patient-ventilator interactions, variability remains on the nomenclature (multiple and ambiguous terms) and waveform interpretation. There are multiple reasons for this variability (legacy terms, language, multiple definitions). In addition, there is no widely accepted systematic method to read ventilator waveforms. We propose a standardized nomenclature and taxonomy along with a method to interpret mechanical ventilator displayed waveforms.
Topics: Humans; Respiration, Artificial; Ventilators, Mechanical; Patients
PubMed: 34470804
DOI: 10.4187/respcare.09316 -
Respiratory Care Aug 2019Airway management techniques are aimed at reducing complications associated with artificial airways and mechanical ventilation, such as retained secretions. The impact... (Review)
Review
Airway management techniques are aimed at reducing complications associated with artificial airways and mechanical ventilation, such as retained secretions. The impact of airway management techniques on ventilator-associated events (VAEs) varies considerably by modality. Closed-suction techniques are generally recommended but have limited, if any, impact on VAEs. Normal saline instillation during suctioning is not recommended. Devices designed specifically to remove biofilm from the inside of endotracheal tubes appear to be safe, but their role in VAE prevention is uncertain. Subglottic secretion clearance by artificial cough maneuvers is promising, but more research is needed to assess its clinical feasibility. Continuous cuff-pressure management appears to be effective in reducing microaspiration of subglottic secretions.
Topics: Airway Management; Humans; Iatrogenic Disease; Intubation, Intratracheal; Pneumonia, Ventilator-Associated; Respiration, Artificial; Suction; Ventilators, Mechanical
PubMed: 31346073
DOI: 10.4187/respcare.07107 -
Respiratory Care Nov 2020Mechanical ventilation is a supportive treatment commonly applied in critically ill patients. Whenever the patient is spontaneously breathing, the pressure applied to... (Review)
Review
Mechanical ventilation is a supportive treatment commonly applied in critically ill patients. Whenever the patient is spontaneously breathing, the pressure applied to the respiratory system depends on the sum of the pressure generated by the respiratory muscles and the pressure generated by the ventilator. Patient-ventilator interaction is of utmost importance in spontaneously breathing patients, and thus the ventilator should be able to adapt to patient's changes in ventilatory demand and respiratory mechanics. Nevertheless, a lack of coordination between patient and ventilator due to a mismatch between neural and ventilator timing throughout the respiratory cycle may make weaning difficult and lead to prolonged mechanical ventilation. Therefore, appropriate monitoring of asynchronies is mandatory to improve the applied strategies and thus improve patient-ventilator interaction. We conducted a literature review regarding patient-ventilator interaction with a focus on the different kinds of inspiratory and expiratory asynchronies, their monitoring, clinical implications, possible prevention, and treatment. We believe that monitoring patient-ventilator interaction is mandatory in spontaneously breathing patients to understand, by using the available technologies, the type of asynchrony and consequently improve the adaptation of the ventilator to the patient's needs. Asynchronies are relatively frequent during mechanical ventilation in critically ill patients, and they are associated with poor outcomes. This review summarizes the different types of asynchronies and their mechanisms, consequences, and potential management. The development and understanding of monitoring tools are necessary to allow a better appraisal of this area, which may lead to better outcomes for patients.
Topics: Humans; Respiration; Respiration, Artificial; Respiratory Mechanics; Respiratory Muscles; Ventilators, Mechanical
PubMed: 32665426
DOI: 10.4187/respcare.07284 -
Respiratory Care Jun 2020Ventilator graphic monitoring is common in ICUs. The graphic information provides clinicians with immediate clues regarding patient-ventilator interaction and ventilator... (Review)
Review
Ventilator graphic monitoring is common in ICUs. The graphic information provides clinicians with immediate clues regarding patient-ventilator interaction and ventilator function. These display tools are aimed at reducing complications associated with mechanical ventilation, such as patient-ventilator asynchrony. It is also useful to assess respiratory mechanics in mechanically ventilated patients using both scalar and plot displays on the ventilator. Additional information can be gained by observing secondary ventilator measures including stress index, inflection points, and work of breathing. Ventilator graphics impact mechanical ventilation management through optimizing effectiveness of patient care and enhancing promptness of clinician response. Despite being a valuable asset in providing high-quality patient care, many bedside clinicians do not have a thorough understanding of ventilator graphics. Mastery of ventilator graphics interpretation is key in managing patients who are receiving ventilatory support.
Topics: Humans; Intensive Care Units; Monitoring, Physiologic; Respiration, Artificial; Respiratory Mechanics; Respiratory Physiological Phenomena; Ventilators, Mechanical
PubMed: 32457168
DOI: 10.4187/respcare.07805 -
Respiratory Care Nov 2014The American Association for Respiratory Care has declared a benchmark for competency in mechanical ventilation that includes the ability to "apply to practice all... (Review)
Review
The American Association for Respiratory Care has declared a benchmark for competency in mechanical ventilation that includes the ability to "apply to practice all ventilation modes currently available on all invasive and noninvasive mechanical ventilators." This level of competency presupposes the ability to identify, classify, compare, and contrast all modes of ventilation. Unfortunately, current educational paradigms do not supply the tools to achieve such goals. To fill this gap, we expand and refine a previously described taxonomy for classifying modes of ventilation and explain how it can be understood in terms of 10 fundamental constructs of ventilator technology: (1) defining a breath, (2) defining an assisted breath, (3) specifying the means of assisting breaths based on control variables specified by the equation of motion, (4) classifying breaths in terms of how inspiration is started and stopped, (5) identifying ventilator-initiated versus patient-initiated start and stop events, (6) defining spontaneous and mandatory breaths, (7) defining breath sequences (8), combining control variables and breath sequences into ventilatory patterns, (9) describing targeting schemes, and (10) constructing a formal taxonomy for modes of ventilation composed of control variable, breath sequence, and targeting schemes. Having established the theoretical basis of the taxonomy, we demonstrate a step-by-step procedure to classify any mode on any mechanical ventilator.
Topics: Humans; Respiration, Artificial; Ventilators, Mechanical
PubMed: 25118309
DOI: 10.4187/respcare.03057 -
Respiratory Care Aug 2019In 2013, the United States Centers for Disease Control and Prevention redefined surveillance for quality of care in ventilated patients by shifting from... (Review)
Review
In 2013, the United States Centers for Disease Control and Prevention redefined surveillance for quality of care in ventilated patients by shifting from ventilator-associated pneumonia (VAP) definitions to ventilator-associated event (VAE) definitions. VAE definitions were designed to overcome many of the limitations of VAP definitions, including their complexity, subjectivity, limited correlation with outcomes, and incomplete capture of many important and morbid complications of mechanical ventilation. VAE definitions broadened the focus of surveillance from pneumonia alone to the syndrome of nosocomial complications in ventilated patients, as marked by sustained increases in ventilator settings after a period of stable or decreasing ventilator settings. Qualitative studies suggest that most VAEs are caused by pneumonia, fluid overload, ARDS, and atelectasis. Only about 40% of clinically diagnosed VAPs meet VAE criteria, likely because the VAE requirement for a sustained increase in ventilator settings sets a threshold effect that selects for patients with severe disease. VAEs are associated with a doubling of the risk of death compared to patients without VAEs and compared to patients who meet traditional VAP criteria. Risk factors for VAEs include sedation with benzodiazepines or propofol, volume overload, high tidal-volume ventilation, high inspiratory driving pressures, oral care with chlorhexidine, blood transfusions, stress ulcer prophylaxis, and patient transport. Potential strategies to prevent VAEs include minimizing sedation, paired daily spontaneous awakening and breathing trials, early mobility, conservative fluid management, conservative transfusion thresholds, and low tidal-volume ventilation. A limited number of studies that have tested subsets of these interventions have reported substantial decreases in VAEs; no group, however, has thus far assessed the impact of a fully optimized VAE prevention bundle that includes all of these interventions upon VAE rates and other outcomes.
Topics: Centers for Disease Control and Prevention, U.S.; Humans; Iatrogenic Disease; Respiration, Artificial; Risk Factors; Terminology as Topic; United States; Ventilators, Mechanical
PubMed: 31346070
DOI: 10.4187/respcare.07059 -
Respiratory Care Aug 2011The use of ventilatory assistance can be traced back to biblical times. However, mechanical ventilators, in the form of negative-pressure ventilation, first appeared in...
The use of ventilatory assistance can be traced back to biblical times. However, mechanical ventilators, in the form of negative-pressure ventilation, first appeared in the early 1800s. Positive-pressure devices started to become available around 1900 and today's typical intensive care unit (ICU) ventilator did not begin to be developed until the 1940s. From the original 1940s ventilators until today, 4 distinct generations of ICU ventilators have existed, each with features different from that of the previous generation. All of the advancements in ICU ventilator design over these generations provide the basis for speculation on the future. ICU ventilators of the future will be able to integrate electronically with other bedside technology; they will be able to effectively ventilate all patients in all settings, invasively and noninvasively; ventilator management protocols will be incorporated into the basic operation of the ventilator; organized information will be presented instead of rows of unrelated data; alarm systems will be smart; closed-loop control will be present on most aspects of ventilatory support; and decision support will be available. The key term that will be used to identify these future ventilators will be smart!
Topics: Equipment Design; History, 18th Century; History, 19th Century; History, 20th Century; History, 21st Century; Humans; Respiration, Artificial; Ventilators, Mechanical
PubMed: 21801579
DOI: 10.4187/respcare.01420 -
Respiratory Care Mar 2021
Topics: Humans; Respiratory Distress Syndrome; Respiratory Insufficiency; Ventilators, Mechanical
PubMed: 33632790
DOI: 10.4187/respcare.08939 -
Respiratory Care Aug 2020Secretion management in mechanically ventilated patients is a paramount task for clinicians. A better understanding of the mechanisms of flow bias and airway dynamic... (Review)
Review
Secretion management in mechanically ventilated patients is a paramount task for clinicians. A better understanding of the mechanisms of flow bias and airway dynamic compression during airway clearance therapy may enable a more effective approach for this population. Ventilator hyperinflation, expiratory rib cage compression, a PEEP-ZEEP maneuver, and mechanical insufflation-exsufflation are examples of techniques that can be optimized according to such mechanisms. In addition, novel technologies, such as electric impedance tomography, may help improve airway clearance therapy by monitoring the consequences of regional secretion displacement on lung aeration and regional lung mechanics.
Topics: Humans; Insufflation; Lung; Respiration, Artificial; Respiratory Physiological Phenomena; Ventilators, Mechanical
PubMed: 32712584
DOI: 10.4187/respcare.07904 -
European Respiratory Review : An... Jun 2023There is a well-recognised importance for personalising mechanical ventilation settings to protect the lungs and the diaphragm for each individual patient. Measurement... (Review)
Review
There is a well-recognised importance for personalising mechanical ventilation settings to protect the lungs and the diaphragm for each individual patient. Measurement of oesophageal pressure ( ) as an estimate of pleural pressure allows assessment of partitioned respiratory mechanics and quantification of lung stress, which helps our understanding of the patient's respiratory physiology and could guide individualisation of ventilator settings. Oesophageal manometry also allows breathing effort quantification, which could contribute to improving settings during assisted ventilation and mechanical ventilation weaning. In parallel with technological improvements, monitoring is now available for daily clinical practice. This review provides a fundamental understanding of the relevant physiological concepts that can be assessed using measurements, both during spontaneous breathing and mechanical ventilation. We also present a practical approach for implementing oesophageal manometry at the bedside. While more clinical data are awaited to confirm the benefits of -guided mechanical ventilation and to determine optimal targets under different conditions, we discuss potential practical approaches, including positive end-expiratory pressure setting in controlled ventilation and assessment of inspiratory effort during assisted modes.
Topics: Humans; Respiration, Artificial; Lung; Respiratory Mechanics; Ventilators, Mechanical; Monitoring, Physiologic
PubMed: 37197768
DOI: 10.1183/16000617.0186-2022