Improving the Quality of Home Mechanical Ventilation
As part of our ongoing commitment to education, Breas Medical were proud to sponsor two symposia at the 2018 JIVD conference in Lyon.
It is our belief that innovation stems from understanding the real-world problems in treating respiratory disorders. Through our continued support to provide free education to respiratory clinicians, Breas aims to improve outcomes for patients from hospital to home.
New technology now makes it possible to monitor your patients that receive home mechanical ventilation. This symposium gave insight into the causes and impact of patient-ventilator asynchrony (PVA). Additionally, delegates learned how to use standard and advanced monitoring tools that are included in the newest generation of ventilators to detect, classify and correct the different types of PVA. Furthermore, the symposium covered the current and future role of telemonitoring that may help to reinforce the way that monitoring is likely to change the organisation of care.
Classification and Clinical Impact of Patient Ventilator Asynchrony: Annalisa Carlucci, Pavia, Italy
In her lecture, Annalisa Carlucci told us that good interaction between patient and ventilator occurs when the patient and the ventilator start a breath at the same time and the breath lasts the same amount of time.
What is poor interaction?
- Ineffective effort
- Double triggering
- Auto triggering
- Late cycling
- Premature cycling
Current evidence tells us that 25% of patients receiving invasive ventilation experience major patient-ventilator asynchrony of >10% of their respiratory efforts (Arnaud et al 2006) and that asynchronies during mechanical ventilation are linked to ICU and hospital mortality (Blanch et al 2015).
Dr Carlucci went on to talk about asynchrony in non-invasive ventilation and stated that there are links between reduced quality of life and patient/ventilator asynchrony. Furthermore, there are proven links between morning dyspnoea in COPD patients and patient-ventilator asynchrony and by improving patient/ventilator synchrony, it is possible to reduce morning dyspnoea (Alder 2012). Sleep, arousals and SaO2 are also improved with improved patient-ventilator asynchrony as shown by Fanfulla and co-workers in 2005.
In some studies, over 50% of patients are not well ventilated during nocturnal NIV. And this poor ventilation with asynchronies may:
- Reduce tolerance and adherence to therapy
- Worsen the quality of sleep
- Cause persistence of alteration or further worsening of nocturnal gas exchange
- Effect long-term outcomes in a subgroup of patients
Dr Carlucci outlined a proposal for a systematic analysis of polygraphy for identifying asynchrony during non-invasive ventilation put forward by an international consensus group called the SOMNONIV Group. The proposal (free download from SPLF: https://bit.ly/2xhI0eC) is to use a combined measure of flow, pressure as well as abdominal and chest movement combined with an algorithm to identify patient/ventilator asynchrony.
Solutions to detect patient ventilator asynchrony; Pay attention to the screen: Jean-Michel Arnal, Toulon, France
Dr Arnal began by outlining how to detect patient-ventilator asynchronies in an easy and general way:
- Observe the patient
- Listen to the ventilator
- Feel the respiratory muscles
- Ask simple questions
- Interpret ventilator waveforms for
- Unintentional leaks
- Upper airway obstruction
- Patient ventilator synchrony
He went on and gave some tips & tricks on how to use the ventilator software while looking for asynchronies.
1. Where to look?
Different asynchronies can be identified at different spots on the ventilator waveform. Inspiratory trigger delay, ineffective effort and autotriggering can be seen at the start of inspiration, flow starvation and overshoot occur during the inspiratory phase while premature cycling, double triggering and delayed cycling can be identified at the end of inspiration.
He went on and gave some tips & tricks on how to use the ventilator software while looking for asynchronies.
2. Use the Time Scale
- Use the overview of the full session to identify leaks
- Use a 5-min scale to look for upper airway obstructions
- Zoom in to a 1-min scale when you suspect patient-ventilator asynchrony
3. Use available sources of information
It can be useful to check the mask information, this describes the expected level of intentional leak based on the prescribed pressures. Check if the value is greater than it should be according to the mask information – this would suggest the presence of unintentional leak.
Dr Arnal also detailed several setting changes that can help to improve certain patient-ventilator asynchronies when they occur:
1. Too much effort needed or ineffective effort to trigger
Increase the inspiratory trigger sensitivity.
Increase PEEP (if a COPD patient then consider intrinsic PEEP).
Decrease the pressure support.
2. Auto triggering
Check for unintentional leak.
Decrease the inspiratory trigger sensitivity.
3. Early Cycling
Prolong the expiratory trigger sensitivity.
Increase Ti Max.
4. Double triggering
Prolong the expiratory trigger sensitivity.
Increase Ti Max.
5. Delayed cycling
Shorten the expiratory trigger sensitivity.
Decrease Ti max.
6. Flow overshoot
Decrease the pressure rise time
7. Flow too low/Flow starvation
Increase the pressure support.
Dr Arnal concluded that often patient-ventilator asynchronies can be detected using waveforms. It has the advantage that it is a non-invasive tool to assess the quality of ventilation. It is however limited as the amount of patient effort is not assessed within the waveforms.
Tighten Your Belts: Advanced Solutions to Diagnose Patient Ventilator Asynchrony: Manuel Lujan, Barcelona, Spain
The lecture from Dr Lujan began by pointing out that there are limitations in built-in ventilator software alone to identify patient-ventilator asynchrony as the information on the patient effort is very limited or even absent. The usage of thoracoabdominal effort belts supplies the clinician with additional and accurate information about the patient’s effort. The basis of inductance plethysmography technique combines Faraday’s and Lenz’s law to create a tracing that reflects the patient’s effort.
So, abdominal and thoracic effort belts reflect the patient’s breathing, whereas inbuilt ventilator software only shows what the ventilator is doing. It is suggested as an additional tool to add to the patient assessment when exploring treatment outcomes.
Information from the ventilator built in software is based only on pressure and flow and therefore has limitations when patients have upper airway events or more complex asynchronies.
Dr Lujan show a comprehensive overview on how the effort belts can add to the differential diagnosis in case a periodic flow reduction is noticed:
| Type | Site (s) | Belts |
| Upper airway obstruction with effort | Oropharynx (AHS) – Fixed anatomical structure – Mask induced | Efforts. Belts out of phase Controlled cycles and effortare not coincidental |
| Upper airway obstruction without effort | Glottic closure | Silence |
| Decrease in ventilatory command | No obstruction | Controlled cycles and belts movements are synchronous |
The use of effort belts offers more information about what is actually happening with the patient during events and asynchronies.
Additionally, effort belts can provide an assessment of thoracoabdominal synchrony.
Following up Your Patients at Home: Telemonitoring Now and in the Future:
Jésus Gonzalez, Paris, France
Dr Gonzalez opened by reminding us of the intended goals of NIV as laid out by Janssens et al in 2011:
- Clinical improvement and reduction in daytime PaCO2
- Mean nocturnal SpO2 >90% for more than 90% of the recording time with no residual SpO2 oscillations
- Create a report from NIV software to validate:
- >4 hours usage per night
- onfirm comfort through no fragmented use
There is evidence to reinforce the importance of obtaining these goals too. Increased leaks can lead to increased mortality (Gonzalez et al 2013). Increased obstructions or less than four hours usage and can also lead to increased mortality (Georges et al 2016) (Borel et al 2015). Changes in daily use can predict exacerbations (Borel et al 2015).
With many feature packed, modern ventilators, monitoring patients at home to ensure they achieve these goals is possible. There is, however, conflicting evidence to suggest whether it may be useful.
Pinto (2010) showed that telemonitoring at home reduced healthcare utilisation and cost. But, Chatwin (2016) found that telemonitoring showed negative results in terms of healthcare costs for patients with home oxygen.
A national project in France is putting homecare providers first with the physician at the end of the pathway where telemonitoring is used to check for ventilator usage, leaks and back-up rate. Three subgroups are monitored: one for the detection of COPD exacerbations, another for nightly compliance of less than four hours and another for discontinuation of treatment in less than one week’s use.
Dr Gonzalez also informed the audience about the upcoming Rescue2-Monitor (R2M) study. R2M is the REspiratory Support in COPD patients after acUte Exacerbation with monitoring the quality of support trial. It is hoped that this trial will show a beneficial outcome for COPD patients and that including polygraphy in the NIV protocol allows to achieve this.
In conclusion, monitoring of home NIV shows to be promising.This monitoring can be done remotely with some devices but better organisation in using these tools is required. Finally, more evidence-based medicine is needed to prove that monitoring home NIV is really useful.
