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Intelligent Ventilation newsletter articles
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Applied physiology at the bedside: Volumetric capnography23.04.2019
Volumetric capnography is the graphical representation of the partial pressure of carbon dioxide (CO2) versus exhaled volume. This measurement is made noninvasively at every breath by a combination of flow and CO2 sensors, which are positioned together at the Y-piece of the ventilator circuit and well synchronized. Volumetric capnography provides much more information than time capnography, primarily about the metabolism, cardiovascular function, ventilation, and ventilation/perfusion (V̇/Q̇) ratio.
volumetric capnography, CO2, PETCO2, ventilation perfusion, ventilation perfusion ratio, ventilation perfusion mismatching, deadspace, cardiovascular function, metabolism, VDaw, alveolar ventilation, CO2 production, VCO2, V'CO2
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Test your IntelliVence (Vol 16 Issue 2)23.04.2019
The volumetric capnography loop displayed is from a passive patient ventilated in PC mode. What does its shape tell us?
volumetric capnography, airway deadspace, PEEP, ventilation perfusion ratio, airway resistance, ventilation perfusion mismatching
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Bedside tip: Using volumetric capnography to set PEEP23.04.2019
PEEP is used to keep the lung aerated and prevent lung collapse at the end of expiration. However, PEEP may over-distend the normally aerated lung and impair lung perfusion. Therefore, any change in PEEP may affect the overall ventilation/perfusion ratio in an unpredictable way.
volumetric capnography, setting PEEP, PEEP, ventilation perfusion ration, recruitment, VeCO2
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Bedside tip: Achieving effective ventilation using volumetric capnography18.02.2019
Ventilation is effective when it removes CO2 at a rate that maintains a normal or a targeted pH.
effective ventilation, volumetric capnography, paco2, petco2, co2 production, co2 elimination, minute ventilation, tidal volume, dead space, alveolar ventilation, V'alv, V'CO2
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Tidal volume and lung-protective strategy in non-ARDS patients18.02.2019
Mechanical ventilation is a lifesaving technique, but one that potentially has important complications. According to several experimental and clinical studies, mechanical ventilation has great potential to augment and initiate injury to the lungs and respiratory muscles (1, 2).
low tidal volumes, lung protection, lung-protective ventilation, non-ARDS, non-injured lung, VILI, lung injury, driving pressure, tidal volume, lung stress, lung strain
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Test your IntelliVence (Vol 16 Issue 1)18.02.2019
The patient is being ventilated in volume assist control mode. What does the change of shape of the pressure curve represent?
flow starvation, inspiratory pressure, flow, pressure curve, inspiratory effort, decrease
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Test your IntelliVence (Vol 15 Issue 6)07.01.2019
This intubated patient is being ventilated in PSIMV+ mode. What kind of asynchrony is visible in the breath marked by the cursor?
Delayed cycling, cycling, flow curve, asynchrony, PSIMV
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Bedside tip: Initial settings for the most important NIV parameters in children19.12.2018
The success of NIV depends on the right choice of equipment and adjustment of the settings to suit each individual child. In this Bedside Tip, we show you the initial settings for the most important parameters when applying NIV therapy in children.
NIV, parameters, pediatric, peak pressure, ETS, pressure support, TI, PEEP, inspiratory trigger, ramp
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NIV for acute respiratory distress in children19.12.2018
In children, it is not uncommon that the rapid progression of respiratory failure with decompensation of the gas exchange may lead to a life-threatening situation. If applied early enough, noninvasive ventilation (NIV) can help stop this progression and thus avoid intubation with invasive mechanical ventilation and the complications that come with it.
NIV, pediatric, PARDS, acute respiratory failure, HFNC, children, PICU, pneumonia, bronchiolitis
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What are we assessing with esophageal pressure measurement19.10.2018
Esophageal pressure measurement is an advanced form of monitoring for mechanically ventilated patients in order to assess transpulmonary pressure and the risk of ventilator-induced lung injuries (VILI), as well as optimize ventilator settings (1, 2). However, there have been concerns about the validity of esophageal pressure to assess pleural pressure (3).
esophageal pressure, measurement, pleural pressure, esophageal balloon, VILI, end-inspiratory, end-expiratory, balloon insertion, inflation, esophageal catheter, transpulmonary pressure, lung stress
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Bedside Tip: How to measure esophageal pressure correctly19.10.2018
A recent physiological study demonstrated that esophageal pressure estimates the pleural pressure at mid-thorax at all levels of PEEP. Therefore, an absolute measurement of esophageal pressure is useful for setting PEEP and monitoring transpulmonary pressure.
esophageal pressure measurement, how to measure, positioning, esophageal balloon, esophageal catheter, inflation, balloon filling, verification, occlusion test
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Test your IntelliVence (Vol 15 Issue 5)19.10.2018
This intubated patient is ventilated in pressure-support mode. What is the explanation for the sudden increase in esophageal pressure?
quiz, esophageal pressure, esophageal contraction, peristalsis, catheter placement, balloon inflation, pressure, esophageal pressure measurement
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Monitoring respiratory mechanics in the prone position14.08.2018
Esophageal pressure measurement can be used to guide ventilator management in severe ARDS patients, and this strategy has been shown to improve oxygenation, lung compliance and possibly survival when compared with standard practice.
prone position, esophageal pressure, measurement, pes, peso, VILI, respiratory mechanics, oxygenation, PEEP, transpulmonary pressure measurement, TPM
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Test your IntelliVence (Vol 15 Issue 4)08.08.2018
Why is the current volumetric capnogram loop different from the reference loop?
pulmonary embolism, capnography, volumetric capnography, dead space, VDalv, PetCO2, capnogram
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Bedside tip: Assessing lung recruitability08.08.2018
The percentage of potentially recruitable lung varies widely among ARDS patients, and zones of collapsed and consolidated alveoli in the most dependent lung frequently require airway opening pressures of more than 35–40 cmH2O to recruit (1).
recruitment, recruitability, hysteresis, assessing, assessment, p/v curve, pressure volume, recruitment maneuver, supine, prone, prone position, PEEP
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Bedside tip: Using measured airway mechanics in pediatrics12.06.2018
The expiratory time constant (RCexp) is measured breath-by-breath on all Hamilton Medical ventilators. As RCexp is the product of compliance and resistance, this single variable gives us an overview of the overall respiratory mechanics.
Rcexp, respiratory mechanics, compliance, resistance, time constant, settings, flow interruption, restriction, obstructive condition, mixed disease, pediatric
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Recommendations for mechanical ventilation of critically ill children12.06.2018
Common clinical practice in pediatric mechanical ventilation is largely based on personal experience or what has been adopted from adult and neonatal studies. There is a fundamental lack of clinical evidence to support the daily practice of pediatric mechanical ventilation, due in part to the extensive variability in lung size, maturity and range of acute and chronic respiratory conditions existing in all age groups of children.
pediatrics, airway mechanics, respiratory system, oxygenation, targets, inspiratory time, frequency, pressure, tidal volume, PEEP, guideline
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Monitoring respiratory mechanics in mechanically ventilated patients30.04.2018
The term respiratory mechanics describes the mechanical properties of the respiratory system that is inflated during mechanical ventilation. Monitoring respiratory mechanics is useful for diagnosing the lung condition, assessing the evolution and severity of the lung impairment, and adjusting ventilator settings.
respiratory mechanics, monitoring, time constant, rcexp, expiratory time constant,
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Test your IntelliVence (Vol 15 Issue 2)25.04.2018
This patient is passive and ventilated in pressure-control mode. Why is the flow curve shaped this way?
pressure control mode, flow limitation, COPD, expiratory flow, bicompartmental expiration, choke point, brochospasm
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Bedside tip: How to use the expiratory time constant25.04.2018
The expiratory time constant (RCEXP) is a dynamic measurement of respiratory mechanics measured breath-by-breath on all Hamilton Medical ventilators.
rcexp, time constant, expiratory time constant, compliance, resistance, monitoring, respiratory mechanics
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Test your IntelliVence (Vol 15 Issue 1)20.03.2018
Why is the flow shape different for the second breath? The patient is ventilated in pressure-support mode with no backup respiratory rate (RR).
auto triggering, inspiratory effort, esophageal pressure, pressure, flow, slope, inspiratory flow, asynchrony, mechanical breath
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Bedside tip: How to set expiratory trigger sensitivity (ETS)22.02.2018
Optimal patient-ventilator synchrony is of prime importance, as asynchronies lead to increased work of breathing and patient discomfort, and are also associated with higher mortality and prolonged mechanical ventilation (1, 2, 3).
ets, expiratory trigger, inspiratory trigger, expiratory trigger sensitivity, asynchrony, delayed cycling, late cycling, trigger adjustment, double triggering, IntelliSync
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Clinical practice guidelines for use of noninvasive ventilation for acute respiratory failure22.02.2018
The use of noninvasive ventilation (NIV) has increased considerably over the last two decades and is now widespread in the acute-care setting for management of acute respiratory failure (ARF). A guideline committee selected 11 questions relating to the clinical application of NIV for various etiologies of ARF based on their perceived clinical importance, and assessed the evidence currently available to develop corresponding recommendations [1].
NIV, guidelines, acute respiratory failure, ARF, noninvasive, noninvasive ventilation, weaning, asthma, post-extubation, respiratory failure, chest trauma, palliative care, post-operative, de novo ARF, immunocompromised, cardiogenic pulmonary edema, pulmonary edema, hypercapnia, hypercapnic, COPD exacerbation, respiratory acidosis
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Test your IntelliVence (Vol 14 Issue 5)19.12.2017
Why is the end-expiratory flow positive (above baseline)?
NIV, noninvasive ventilation, leak compensation, end-expiratory flow, leak rate
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High flow oxygen therapy after planned extubation19.12.2017
Oxygenation and ventilation impairment after planned extubation is frequent. Post-extubation respiratory management aims to decrease the risk of early acute respiratory failure and reintubation, which is associated with a poor prognosis (1).
high flow oxygen therapy, HFOT, extubation, oxygenation impairment, reintubation, post-extubation respiratory failure, high-risk patients, NIV, non invasive ventilation
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Bedside tip: How to set high flow oxygen therapy15.12.2017
High flow oxygen therapy combines several physiological effects: Oxygenation, PEEP, an increase in the end-expiratory lung volume (EELV), a lower respiratory rate (RR), a decrease in intrinsic PEEP and work of breathing, lower PaCO2, and improved humidification and comfort (1, 2). The optimal flow setting depends on the indications and the desired physiological effect.
high flow oxygen therapy, HFOT, settings, oxygenation, PEEP, flow
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Test your IntelliVence (Vol 14 Issue 4)02.10.2017
What causes this temporary stop in breathing?
Cheyne stokes, CSR, apnea, stop breathing
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Bedside tip: How to perform a recruitment maneuver02.10.2017
A recruitment maneuver (RM) is a transient increase in transpulmonary pressure applied to reaerate the collapsed lung.
recruitment, recruitment maneuver, ARDS, PEEP, sustained inflation, PV Tool
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Clinical practice guidelines for mechanical ventilation in adult patients with ARDS02.10.2017
Acute respiratory distress syndrome (ARDS) is characterized by an inflammatory pulmonary edema resulting in severe hypoxemia. The recent LUNG SAFE study showed that ARDS is common in the ICU, occurring in 10% of all patients admitted (1).
ARDS, VILI, guideline, mechanical ventilation, mortality, tidal volume, inspiratory pressure, prone positioning, HFOV, PEEP, recruitment maneuvers, ECMO, recruitment
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Bedside tip: How to select SpO2 targets30.08.2017
In mechanically ventilated patients, SpO2 targets are selected according to the previous lung condition and the actual severity of the disease.
spo2, spo2 targets, ARDS, normal lung, hypercapnia, brain injury, PEEP
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Bedside tip: How to measure driving pressure30.08.2017
Airway driving pressure is associated with clinical outcomes in ARDS, post-surgical, and normal-lung patients, and is a measure of the strain applied to the respiratory system and the risk of ventilator-induced lung injuries. Evidence suggests we should keep driving pressure below 14 cmH2O. But how can we measure it?
driving pressure, hold maneuver, end-expiratory, end-inspiratory, plateau pressure, PEEP, ASV
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Bedside tip: How to wean with ASV®30.08.2017
The American Thoracic Society and the American College of Chest Physicians recently provided recommendations to help optimize liberation from mechanical ventilation in adult ICU patients (1). They suggest using a ventilator liberation protocol and performing spontaneous breathing trials (SBTs) with modest inspiratory pressure support (5-8 cmH2O). So how do we implement these recommendations using the Adaptive Support Ventilation (ASV) mode?
weaning, wean, ASV, recommendations, liberation, protocol, criteria, readiness-to-wean
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Test your IntelliVence (Vol 14 Issue 3)29.08.2017
What causes the distortions of pressure and flow during the second breath?
triggering, reverse triggering, muscle contractions, insufflation, double inspiration
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Test your IntelliVence (Vol 14 Issue 2)29.08.2017
Why are there oscillations in the pressure and flow waveforms?
oscillations, pressure waveform, flow waveform, proximal airways, distal airways, secretions
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Clinical practice guidelines for weaning critically ill adult patients from mechanical ventilation29.08.2017
Due to the complications associated with mechanical ventilation, clinicians should implement strategies to liberate patients from mechanical ventilation as soon as the underlying cause for mechanical ventilation has sufficiently improved, and the patient is able to maintain spontaneous breathing unassisted.
Weaning, guidelines, liberate, liberation, recommendations, protocol, mechanical, ventilation
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Findings from the "Lung Safe" ARDS Epidemiology Study29.08.2017
The Lung Safe study Epidemiology, Patterns of Care, and Mortality for Patients With Acute Respiratory Distress Syndrome in Intensive Care Units in 50 Countries (1) evaluated the recognition, incidence, mortality and management of ARDS in 450 ICU’s in 50 countries. The results of the study may be somewhat surprising in comparison to common perceptions.
ARDS, study, epidemiology, lung safe, criteria
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Acute Respiratory Distress Syndrome In the Adult and Pediatric Population29.08.2017
Acute Respiratory Distress Syndrome (ARDS) is a potentially devastating clinical disorder, affecting critically ill patients of all ages. Hypoxemic respiratory failure is a common characteristic, requiring invasive or non-invasive mechanical ventilation. Mechanical ventilation provides critical support while clinical interventions and recovery time allow potential resolution of the acute disease process. However, clinically inappropriate techniques utilizing mechanical ventilation can further precipitate lung injury and possibly delay or prevent recovery.
ALI, acute lung injury, ARDS, distress syndrome
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Driving pressure in ARDS patients29.08.2017
ARDS is characterized by lung collapse and consolidation leaving just a small portion of aerated lung remaining, which is at risk of ventilator-induced lung injuries (baby-lung concept).
driving pressure, lung safe, limiting driving pressure, hospital mortality, ARDS
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Hyperoxemia in the ICU29.08.2017
Hyperoxemia can be defined as an increase in arterial oxygen partial pressure (PaO2) to a level greater than 120 mmHg (16 kPa) (1, 2). It is considered to be moderate for levels ranging between 120 and 200 mmHg, and severe if PaO2 exceeds 200 mmHg (27 kPa) (3). Hyperoxemia is caused by hyperoxia (an increase in oxygen) and occurs in 22% to 50% of mechanically ventilated patients in the ICU (1, 3-6).
hyperoxemia, hypoxia, hyperoxia, mortality, PaO2, SpO2, pulse oximetry, oxygenation, closed loop, Intellivent
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Test your IntelliVence (Vol 14 Issue 1)13.07.2017
What does this small bump at the beginning of expiration represent?
expiration, premature, cycling, cycles, inspiratory, effort, insufflation, trigger sensitivity
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