A. Kindler1, L. Müller2, J.C. Schefold2, S. Eggmann1
1Inselspital, Bern University Hospital, Department of Physiotherapy, Insel Group, Bern, Switzerland, 2Inselspital, Bern University Hospital, University of Bern, Department of Intensive Care Medicine, Bern, Switzerland
Background: Diaphragm weakness is a frequent complication of mechanical ventilation resulting in weaning failure and increased mortality. Inspiratory muscle training (IMT) may increase diaphragm strength, thus reducing duration of mechanical ventilation and improving functional outcomes. IMT is considered safe in critically ill patients but has not been established for tracheotomised patients.
Purpose: This study aimed to evaluate the feasibility and safety of IMT in tracheotomised, critically ill adults. Secondary endpoints were maximum inspiratory pressure (MIP) and respiratory function measured with the Chelsea Critical Care Physical Assessment Tool (CPAx) from baseline to intensive care unit (ICU) discharge.
Methods: STRONGER is a prospective observational study conducted in an interdisciplinary ICU of an academic centre. From January to September 2019 all newly tracheotomised patients were included for evaluation of IMT. According to our pre-existing protocol, IMT was not performed in patients with a cervical spinal-cord-injury, a pre-existing diaphragmatic paresis, a tracheotomy due to an upper airway issue, patients receiving palliative care or in pregnant women. IMT was performed daily with 2 times 6 repetitions against a threshold resistance of 30% of the measured MIP regardless of the ability to follow commands. Intensity, feasibility and adverse events were documented by the treating physiotherapist. Data were analysed descriptively.
Results: Over the nine-month study period, 104 patients were tracheotomised of whom 85 were eligible for IMT. These participants had a mean age of 63±12 years, an APACHE-II score of 30±8 and were predominantly male (56[66%]). Reasons for tracheotomy included weaning failure 48(56%), reduced alertness 28(33%) or dysphagia 9(11%). Overall, 287 possible sessions were evaluated and 223(78%) IMT-sessions were performed per protocol with a median (IQR) of 2(2-4) sessions per patient. Main reasons for missing a training were controlled ventilation (15[23%]), tachypnoea (>30) (10[16%]), surgery (9[14%]), other therapeutical priorities (9[14%]), forgotten by the physiotherapist (4[6%]) or refused by the patient (2[3%]). There were no serious adverse events, but 10(4.5%) training sessions were discontinued. Reasons included failure to open the valve (5[50%]), increase in respiratory rate (>35) 2(20%), patient refusal (1[10%]), patient agitation (1[10%]) or an increase in blood pressure (1[10%]). All incidences resolved upon therapy-discontinuation and were of no further consequences. The median (IQR) of the MIP was 11.5(6.25-19.75) at baseline and 19.5(10.25-28.75) at ICU discharge, which equals a statistically significant increase (Wilcoxon test: p<0.001, n=50). Similarly, respiratory function of the CPAx increased significantly from baseline (3[2-3]) to ICU discharge (3[3-5], p<0.001, n=57).
Conclusion(s): The use of a standardised IMT-protocol by physiotherapists was feasible and safe in tracheotomised, critically ill adults. Overall, 78% of possible trainings were performed without any adverse events. This included participants with a reduced alertness who were unable to follow commands. IMT was discontinued in 4.5% of all trainings without further consequences.
Implications: IMT in tracheotomised patients was feasible and safe when implemented by certified physiotherapists in clinical practice. The applied intensity (2x6 repetitions, 30% of MIP, once daily) can therefore be recommended for safe implementation. IMT may further be useful in patients with a reduced vigilance. Nevertheless, more research is needed on the efficacy of IMT.
Funding, acknowledgements: No.
Keywords: Inspiratory muscle training, ventilator-induced diaphragmatic dysfunction, weaning
Topic: Critical care
Did this work require ethics approval? Yes
Institution: Inselspital, Bern University Hospital, Bern, Switzerland
Committee: Ethics Committee of Bern, Switzerland
Ethics number: Original study number: ID 2018-01888 (approved on December 11, 2018)
All authors, affiliations and abstracts have been published as submitted.
