Non-Invasive Ventilation of the Restricted Thorax: Effects of Ventilator Modality on Quality of Life The North Study Lorna Cummins RRT, Pat Hanly MD, Andrea Loewen MD, Karen Rimmer MD Raymond Tye RRT, Kristin Fraser MD
Financial Interest Disclosure Lorna Cummins RRT I have no conflict of interest.
Objectives To increase awareness of newer options for the non- invasive ventilation (NIV) of patients with restricted chests To share the results of a pilot study To consider future directions for application of newer NIV modalities to special respiratory populations
Outline Background and terminology Study Objectives Study design Challenges Results Next steps
Background There has been an international movement towards the use of newer, emerging modes of NIV In 2012, The Alberta government funding for NIV began supplying bi- level machines with more options and modes A couple of advanced- stage NM patients attended the clinic and they reported dramatic improvements when changed from traditional Bi-Level S/T to (now available)bi-level PC mode
Background Until recently, Bi-Level S/T was the only mode on our Bi-level machines that was available for patients requiring either of: 1) a back up rate 2) time cycled breath in order to optimize ventilation Next four slides will explain the difference between these 2 modes I have made reference to
Bi-Level S/T Spontaneous (S) : flow cycled breath -Patient triggers the breath -Patient controls cycling to expiration (predetermined drop in peak inspiratory flow is felt to represent end of patient respiratory effort) From Rabec C et al. Thorax 2011;66:170-178
Bi-Level S/T Timed (T) machine cycled breath -Machine triggers the breath -Machine controls cycling to expiration determined by preset inspiratory time. From Rabec C et al. Thorax 2011;66:170-178
Bi-Level S/T often two types of breaths in one patient Variable Effects on comfort, synchrony, ventilation From Rabec C et al. Thorax 2011;66:170-178
Pressure/Control Mode machine time cycled breath The PC mode delivers all breaths as a machine time-cycled breath. The PC mode is a pressure limited, time cycled mode, regardless of whether the breath is patient or machine triggered.
Pressure/Control Mode for the restricted chest Advantages: Achieve set IPAP Improved Vt by controlling Ti ( lower RR) Consistent Breathing, all breaths are similar Spontaneous breaths can still occur but with a consistent Ti, don t have to overdrive respirations
Objectives To identify restricted patients- neuromuscular or chest wall disease- that were not being optimally ventilated with the standard flow cycled Bi-Level S/T mode NIV To determine if they could be more effectively treated with a time cycled P/C mode NIV The primary outcome was change in Quality of Life Score, measured by the Sleep Apnea Quality of Life Index ( SAQLI) The secondary outcomes were: adherence, ventilation, comfort, blood gases.
Study Design This was an pre, post- interventional study
Methods We planned to recruit 20 patients at two sites in Calgary during annual BiLevel follow-up visits. Inclusions Chronic NM or Chest wall restrictive disease On Bi-level -S/T mode for more than three months, and stable Medically stable FVC < 80% Exclusions COPD, haemoptysis, pneumothorax, increased intracranial pressure, decreased LOC, pleural effusion, impaired swallowing, current tracheostomy
Methods: Finding Eligible Patients
Shallow Breathing Index (SBI) SBI= f/vt where f = average respiratory rate and Vt = average tidal volume in ml Derived from RSBI used in ICU as a parameter to measure work of breathing during a trial of spontaneous breathing during weaning- predicts success arsbi has been calculated for those on NIV during acute respiratory failure to predict impending respiratory failure Anecdotally, SBI has been used for assessment of adequacy of NIV in Chronic Respiratory failure but to date has not been validated for this use. SBI = Work of Breathing High WOB fatigued muscles +/- Poor sleep poor daytime function QOL
Methods-Measurements Eligible patients were asked for informed consent At First visit: SAQLI administered by RRT 1-2 hour daytime trial of time cycled (PC) mode Initiated on new settings, PC mode ±AVAPS Clinical Follow up at 14 days SAQLI and download parameters collected at 3 months
Why QOL as primary outcome Our impression is that titration of NIV in those with Chronic Respiratory Failure is complex and issues include QOL is affected by the disease and the therapy Comfort awake must be balanced against optimal sleep titration Compliance is affected by settings and synchrony Titrating to Ideal ABG might not result in overall compliance/ better sleep QOL measure will capture many/all of these issues and their interactions
Sleep Apnea Quality of Life Index (SAQLI)-short version The Calgary Sleep Apnea Quality of Life Index (SAQLI) is a diseasespecific HRQOL tool developed and validated for use in Sleep Apnea populations SAQLI evaluates five domains :(A) Daily functioning (B) social interactions (C) emotional functioning (D) symptoms and (E) treatment-related symptoms. The SAQLI is designed for interviewer administration. Subjects respond on a seven-option Likert scale. It has been shown to be valid for sleep apnea patients in western countries and also has been validated after translation into both Cantonese and French It is more responsive to treatment interventions than other available QOL tools- the meaningful clinically important difference is 1 unit
Daytime Trial 1-2 hours Sleep Physician and RRT guided trial Location: Sleep Centre bedroom continuous oximetry (SpO2) transcutaneous CO2 monitoring (TcPCO2) HR RR Mask Fit Clinical examination of respiratory comfort and work of breathing Bi-Level feedback re: Vt, RR, VE On home settings then switched to Pressure control mode Goals: tidal volume ( 4-8 ml/kg ideal body weight) RR<20 and comfortable for patient Synchrony with NIV Comfort re: rise time and Ti SaO2 and TcCO2 optimization
Challenges Multiple medical co-morbidities Some had to be convinced that we might be able to do better felt OK before Poor mobility of some, limited access to our centre so we limited follow up to 2 visits, and focused outcomes on QOL
Comments-Next Day Patients were called the next day and they had already experienced more consolidated sleep, slept longer, headaches were gone and SpO2 was higher than usual upon awakening
Comments-Two weeks Alert, awake, feels better, can t describe why More energy, less fatigue Can take a deeper breath Good consolidated sleep Nasal congestion gone, bi-level not blowing her head off Can walk to mail box to get mail! Download, clinical assessment and changes to bi-level done at this visit
Comments-Three months Can now shower, increase energy, goes for walks, amazed and excited about life Back in choir, singing in church One found in her yard singing One patient could no longer sleep as long so had to adjust her time in bed Download, SAQLI, ABG and clinical assessment done at this last visit
Results
Results There was a trend towards improvement in Tidal Volumes PaCO2 Minute Ventilation Hours of adherence % of night adherent >4hours
Result by patient SAQLI SBI
Conclusions We identified so far 8 patients with restricted ventilation on chronic NIV who were not optimally treated Overall, patients with restricted chests converted from flow- cycled ventilation to time-cycled ventilation showed significant improvement in QOL SBI dropped significantly suggesting that this might be a reasonable parameter for measuring response in this group Trends towards improved gas exchange (ABG and Vt), reports of improved NIV comfort and improved sleep quality suggest that the QOL improvement relates to many of these factors
Future Directions The availability of new modes of ventilation for NIV has fuelled a need for: Better ways to identify those that are not optimally treated Studies to assess optimal modalities for the subgroups of those on NIV (OHS, ALS, chest wall vs. neuromuscular) Consideration of the best outcome measure in these complex patients : Focus on QOL outcomes Multidisciplinary care that includes nocturnal PSG technologists, Respiratory therapists in clinic and at home, and improved communication strategies