EFFECTIVENESS OF INSPIRATORY MUSCLE TRAINING AND HIGH FLOW NASAL CANNULA OXYGEN THERAPY ON PHYSIOTHERAPY OUTCOME MEASURES IN DIFFICULT WEANING PATIENTS

A. Christakou^1,2, D. Tsimouris³, A. Skoura⁴, A. Xatzimina³, E. Patsaki^1,2, M. Papadopoulos¹, A. Kouvarakos¹, M. Katartzi¹, E. Grammatopoulou², N. Koulouris⁵, S. Zakynthinos⁶, E. Ischaki⁷

Background: Difficult to be weaned off the mechanical ventilation (MV) patients have a prolonged intensive care unit (ICU) stay with detrimental effects on muscle strength and functional ability. Inspiratory muscle training (IMT) has been proved to be an effective physiotherapy intervention for the prevention of inspiratory muscle weakness. Additionally, High Flow Nasal Cannula (HFNC) oxygen therapy has been shown to support oxygenation and prevent re-intubation of critically ill patients.

Purpose: To investigate the efficacy of combining IMT and HFNC on physiotherapy outcome measures e.g., maximal inspiratory and expiratory strength, endurance of respiratory muscles, peripheral muscle strength, functional ability in patients at high-risk for weaning failure.

Methods: This study is part of an ongoing prospective randomized controlled trial, where 225 consecutive mechanical ventilated ICU patients were recorded from March 2019 to April 2020. 36 difficult weaning patients with failed first spontaneous breathing trial had one of the following characteristics: >65 years, BMI> 35kg/m2, weak cough, heart and lung comorbidities, hypercapnia, > 72hours on MV. The sample was randomly assigned to: IMT - HFNC group and IMT - Venturi mask group. From the beginning of weaning, IMT (5 sets of 10 breaths) was administered twice a day and for the weekends once a day. Loading was set at the 30% of the initial Μaximum Ιnspiratory Pressure value (MIP) with an increase of 10% daily. Inspiratory muscle strength was estimated through measurement of MIP and Maximum Expiratory Pressure (MEP) at three time points: awaking, extubation and ICU discharge. Fatigue Resistance Index (FRI) was used to assess respiratory muscle endurance at awaking, extubation and ICU discharge. Medical Research Council Scale (MRC) was used to measure peripheral muscle strength at four time points: awaking, extubation, ICU and hospital discharge. Functional Independence Measurement (FIM) was used to evaluate functional ability at two time points:  ICU and hospital discharge. For the present study, differences were examined for the whole sample across time.

Results: The sample of 36 patients (20 men, 16 women; age 60.3 ± 17.8 years, SOFA 6.6 ± 2.4, APACHE II, 13.0 ± 5.0, length of stay in ICU 12.8 ± 5.9 days, MV duration 7.5 ± 5.1 days) were eligible for the study. Across time, and for the total sample: a) statistical significance was found for MRC and FIM (p<0.0001), and b) no statistically significant differences were found for MIP, MEP, FRI and MRC.

Conclusion(s): The present study showed some preliminary data for the total sample. However, no conclusion can be drawn regarding the effectiveness of the combination of IMT and HFNC on physiotherapy outcome measures yet in difficult weaning patients. Data between groups of this ongoing trial will draw safer conclusions.

Implications: The present study might contribute on physiotherapy treatment of difficult weaning patients.

Funding, acknowledgements: No external funding

Keywords: Inspiratory Muscle Training, Difficult weaning, Strength and functional ability

Topic: Critical care

Did this work require ethics approval? Yes

Institution: General Hospital of Athens 'Evaggelismos'

Committee: General Hospital of Athens 'Evaggelismos'

Ethics number: ClinicalTrials. govID: NCT03908658