Muscle Recruitment During Neck Flexion and Inspiratory Muscle Training

Summary

Respiratory muscle dysfunction is highly prevalent in patients with prolonged weaning from mechanical ventilation and is strongly associated with weaning failure. Efforts to strengthen the respiratory muscles, aimed at reversing or minimizing the impact of respiratory muscle weakness on clinical outcomes, have generally focused on the diaphragm with specific inspiratory muscle training (IMT) exercises. However, the effectiveness of these exercises and impact on clinical outcomes are not current practice in the majority of ICUs, as they are hardly feasible in ICU patients who often cannot be disconnected from the ventilator and cannot fully cooperate.

Promising results have been published concerning non-respiratory training techniques, which can also target the accessory muscles, particularly important in the presence of increased load to the respiratory system, as in the case of the weaning phase. These non-respiratory training techniques would have the advantage of not entailing disconnection of the patient from the ventilator. In particular, in healthy subjects, a quasi-isometric neck contraction, called neck flexion, appeared to generate greater or comparable recruitment of some principal and accessory muscles of respiration, when compared to conventional IMT. However, this has not been studied in patients requiring prolonged mechanical ventilation, for whom IMT with threshold loading devices remains the primary recommended rehabilitation strategy.

Therefore, the primary aim of the investigators is to assess the feasibility, tolerability, and safety of neck flexion and to compare them with IMT technique in patients with difficult and prolonged weaning from mechanical ventilation. Secondary aims are: i) to characterize which respiratory muscles are recruited and their level of activation at different levels of ventilatory assistance and ii) to assess which respiratory muscles are recruited and their level of activation during the two techniques and to compare these findings.

The hypothesis of the investigators is that neck flexion will be feasible (more than conventional IMT), well tolerated, and safe in patients with difficult and prolonged weaning. The investigators also hypothesize that, reducing the level of assistance and during unassisted breathing, a progressively increasing activation of the diaphragm, neck and trunk respiratory muscles, reflecting increased ventilatory load, will be fund. Finally, the hypothesis of the investigators is that the level of muscle activation/recruitment during neck flexion will be comparable or even greater to that occurring during IMT, as found in healthy subjects.

Finding a new and highly feasible rehabilitative technique, able to recruit and train the respiratory muscles (including accessory muscles), will have the potential to promote patients' weaning and improve all related clinical outcomes, and therefore to dramatically shift the paradigm about the role of rehabilitation in ICU.

Conditions

• Mechanical Ventilator Weaning
• Respiratory Muscle Training

Interventions

OTHER

Quasi-Isometric Neck Flexion

Patients will be asked to minimally lift their head from the pillow generating a quasi-isometric neck contraction (2 sets of 6-10 flexions).

OTHER

Inspiratory Muscle Training

Patients will be asked to complete 2 sets of 6-10 breaths through a POWERbreathe device, which applies a variable resistance provided by an electronically controlled valve (variable flow resistive load). During each IMT and neck flexion maneuver ultrasound measurements will be performed (measurements of the diaphragm, sternocleidomastoid, parasternal intercostal, internal oblique \[IO\], external oblique \[EO\], transversus abdominis \[TrA\] and rectus abdominis \[RA\] will be taken) and, during the entire period, sEMG monitoring of the target muscles (diaphragm, sternocleidomastoid, parasternal intercostal and EO) will be continued.

Sponsors & Collaborators

• Unity Health Toronto

  lead OTHER

Study Design

Allocation

RANDOMIZED

Purpose

OTHER

Masking

SINGLE

Model

CROSSOVER

Eligibility

Min Age

16 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2023-02-09

Primary Completion

2025-11-15

Completion

2025-11-15

Countries

• Canada

Study Locations